The base: '87 Fiero GT - owned for about 4 years and used as a daily driver just untill some a$$hole vandalised the car !
The mods allready undertaken: RDickman ball-joint lowered front, homemade coilover rear, big brake booster conversion, 7730 ECM (no longer needed as I'll be going 3800), modified Fiero intake and a few other little mods to make the 2.8 breath (again no longer needed).
The major works underway: Total body panel off respray - all painted now in two tone Maserati Green. I won't be putting the panels back on untill the engine swap is finished. 3800 series 2 engine (to be prepared) and big(ish) GT 3776 turbo.
Concerning the 3800 engine, I would like some feedback from you "guys-n-gals" because you're the greatest 3800 experts and I love all your write-ups on your engine swaps !
I won't go into how difficult it is to find a (good) series 2 engine in Europe! Let's just say I learn't very quickly the difference between a series 1 and series 2 !! (DarthFiero knows what I'm talking about !! --> I should write a book: "Engine ID for dummies" !!) Well after a 3600km round trip to northern Germany, I am the proud owner of an '98 series 2 N/A 3800 with only 5K miles on it ! (Ex Chevy Lumina staff car used on a now decommissioned US military base - don't ask me how the locals got hold of the staff cars after the base was vacated? All I know is that this engine is spotless ! No wear at all !)
So what do you think ? What should I do in order to make a good reliable high output turbo motor? Just to let you know, I don't have limited budget (within reason!), but I don't want to spend mega Euros on things that won't really help make this a good fast road going Fiero. I want to be able to "sting" a few Porches on the Nürburgring but this is not going to be an all out stripped down race car.
Here is what I think needs to be done: S/C rods and forged pistons. Off the shelf turbo cam (Stage 2, XP or eqivalent) with stock ratio rockers. Custom stainless steel exhaust headers in order to mount the turbo at equal distance from the two banks. (Will be homemade as I'm a very good welder.) Light head work just to port and polish the runners. Necessary mods to fuel system - 60# injectors, good fuel pump etc... Intercooler - thinking of a water/air unit with a secondary radiator up in the front. Big oil cooler.
As I said earlier, I am looking for feedback/experience from those that have allready gone this way?
I will put up some photos as soon as I have remembered where my photobucket account is ??!
The 3800 motor as it was on Sunday afternoon before dismanteling:
And the motor 4 or 5 hours later after the strip down:
Here is the turbo - brand new, never used and bought for 1/2 price!
And to finish, here are some of the body panels being painted by my local garage:
So there it is for the moment. I will post a few more photos tomorrow of the balance shaft removal and oil hole plug (got the day off work - yeah!). I will also be drilling a few more oil return holes in the valley.
First of all, good luck on this project. It should be a great project, but will be hampered by access to parts.
One of the first things I would suggest is to find a series II N/A intake manifold from a Camaro or Firebird on Ebay and have it shipped to you. You should be able to find one for around $125 or so. This intake manifold is made of aluminum and should hold up better for your application. It also would point the throttle body in the direction of the normal battery mount.
The second thing I would suggest is to go with a direct air to air heat exchanger for the intercooler. While the water cooled ones work they are first of all less effective because you have two boundaries to transfer heat across. The first one is the front radiator so you have an air to water interface which can only cool to a few degrees above ambient. Then you will have another heat transfer boundary at the water to air intercooler, which will also have a delta T or difference in temperature across it. If you use a direct air to air intercooler you will have lower Delta T and better cooling of the charged air. DarthFiero has been very effective in mounting the intercooler under the car just in front of the engine, with a bit of ducting to guide the air over the intercooler.
The reason I know anything at all about this is that I have been considering doing this too. However, for now it is on hold.
There are a lot of other people out there that can give you more specifics about a turbo installation.
Rafe, it sounds like you are pretty much on-track for what you are wanting to build here. I think the forged pistons and stock S/C rods are a good idea; just make sure your machine shop does a good balance job on the complete rotating assembly when you do the build.
I will echo what MadMark said and suggest the use of a 95-98 Camaro/Firebird 3800 intake since it is all-aluminum (99-02 F-body 3800 intakes can also be used but had a different throttle body and different angle of mounting it on the intake). If you get the valve covers off of one of these engines those are metal too so you can have them powdercoated. Using this 95-98 F-body intake in a Fiero points the throttle body at the stock Fiero battery location which means you'll need to move the battery and remove the battery tray; but makes charge air pipe routing from an air-to-air intercooler mounted under the car (in front of the cradle) a snap.
The 3800 Series 3 N/A FWD (L26) engine did also have an all-aluminum intake but the throttle body points at the passenger side of the car. And if you are going to mount your turbo over the transmission - this won't leave you with very much room over there for charge air piping if you plan on running any intercooler.
In addition to what Mark said about the water-to-air coolers, keep in mind they do add considerable weight and complexity to the car; plus you have to run a pair of water lines for it up to the front of the car which you really don't have room for under the Fiero. Another drawback of that system is you don't know if it is working or not unless you have some kind of temp sensor mounted in the charge air cooler portion to tell you if it is cooling the charge air effectively or not. I've seen several people toast engines that had air-to-water charge cooling systems because the pump failed or some other situation occured in the system that caused the coolant to stop flowing (such as an air pocket). An air-to-air intercooler is much more simple and it just works. The only way it stops working is if it gets clogged up by excessive road debris (like paper, plastic, trash, etc) or a dead animal. But I'm sure you're going to know if you run over something big enough to cause a problem.
Truth be told in all the years I've driven my car with the IC mounted under it; I've never had anything clog it up - and I have run over some animals (dead or otherwise).
-ryan
------------------ OVERKILL IS UNDERRATED Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com
Originally posted by MadMark: The second thing I would suggest is to go with a direct air to air heat exchanger for the intercooler. While the water cooled ones work they are first of all less effective because you have two boundaries to transfer heat across. The first one is the front radiator so you have an air to water interface which can only cool to a few degrees above ambient. Then you will have another heat transfer boundary at the water to air intercooler, which will also have a delta T or difference in temperature across it. If you use a direct air to air intercooler you will have lower Delta T and better cooling of the charged air. DarthFiero has been very effective in mounting the intercooler under the car just in front of the engine, with a bit of ducting to guide the air over the intercooler.
I have to constructively disagree here. It sounds logical in theory but without documented results I don't believe this to be true in a Fiero based on my experience with the subject in a Fiero. I mounted an intercooler just ahead of the cradle and went a step further by having it hang about 2" below the cradle so that it would partially receive direct exposure to the expected air stream under the car.
The end result proved to be a waste of time and effort, the amount of air flowing under the car toward the intercooler was not sufficient enough for me to note any significant difference in the air inlet temps on the datalog when comparing the before and after install temps. In the process I scored a direct hit over a dead animal in the road so in a way I was punished for my efforts with having to clean that crap out of the core afterwards.
Further more, with such little air flow underneath the car, I'd expect a fan setup sufficient enough to do a proper job would consist of some serious shielding and shrouding work to prevent the same kind of hot air recirculation that can occur up front with the coolant fan if you remove the upper and lower dam system as well as some very good fans/motors and not the ebay type 7-10" fans where the center disc takes up about half the diameter. Until someone shows data that proves different from what I experienced. The air to water intercooler will very likely perform very well as long as the radiator is up front and in the air stream.
I don't buy the poor efficiency theory due to the dual exhcange cores at all, especially when you consider how well the little heater core a number of times smaller than a proper sized liquid air cooler heats up the car. If that little heater core can put out air hot enough to make it difficult to hold your hand close to the vent (mine does), a liquid to air intercooler should have very good heat exchange ability provided the radiator is sized correctly. Having mounted an intercooler in the front of the car and in the rear, I don't see an air to air cooler in front of the cradle besting a good liquid to air setup even with fans and so far no one with either system in a Fiero has posted datalog numbers to give any further insight.
The plastic L36 intake has been proven to be a great performing intake... and pressure tests to well over 100PSI without issue.
I have ran a plastic intake on multiple turbo cars for years now without a single issue, and dyno proven power.... I dont see why these wannabees are coming into this thread saying you need to have an aluminum one.
Good input from all of you. However, I'm a couple of months away from buying any of the intake system - so we'll talk plastic, aluminium, left/right facing, air/water, air/air, mounting position etc... once the engine is back on the subframe (cradle).
What are your ideas about compression ratio? Bearing in mind that in Europe I can fill my car with 95 or 98 grade fuel, should I consider going to the highest comp ratio pistons available? The 9.5:1 ones. Is this pushing it a bit with iron heads ? What are you running ? 8:1? 8.5:1? 9.5:1? Yes I know we'll come back to the inter-cooler question, but lets just say that there will be good inter-cooling.
I do have a little experience with turbo engines having raced a Renault 5 Gordini Turbo in the past. This car was not inter-cooled (draw through carburettor) and in order to boost higher, we used to decompress the engine with a thicker head gasket down to about 7.5:1. However, this made bottom end response rather sluggish. But wow did that thing fly once the engine hit 3500 rpm and the turbo really started to boost! For the Fiero, I would like to avoid burning out my tires in 4th gear at 110km/h because the turbo kicks in super hard and uncontrollably! (I remember Justin's write-up of a similar experience.)
I think that keeping a reasonably good atmospheric phase of the motor with higher compression is the way to go. Not exploding my Getrag with shock loading would also come into the equation!
Rafe
[This message has been edited by Englishrafe (edited 02-24-2012).]
Bearing in mind that in Europe I can fill my car with 95 or 98 grade fuel,
keep in mind over there gas is graded differently, so your 95-98 ratings are not even close to the US ratings. We take the high and low and avg the rating, over there they just use the high rating, FYI.
Our 95 is eqivalent to your 85 and our 98 is eqivalent to your 88. I think that comes from the RON - Research Octane Nomber and the MON - Motor Octane Number measuring methods used. Whatever, I can, in general, put higher grade fuel in my tank in Europe. Most Europeen car manufacturers make higher compression motors than their American counterparts. We have also E10 fuel which is supposed to be quite good too ? Anyway, I think that I could run higher compression ratio in this motor? Rafe
I would never mount an IC like that. I think you are asking for trouble (the real possibility of something hitting and damaging it). Did you have electric fans mounting on this IC that you had hanging on there like that?
Here's how I've set them up in my builds:
This one in particular had 2 electric fans mounted on it (on the topside) and a tall air deflector, the bottom of which originally sat about 1 inch off the ground. This forced the air coming under the car up into the intercooler because there really wasn’t any other way for the bulk of that air to go under it nor around the sides (because the sides of the deflector were relatively close to the tires). However, with the bottom of that deflector only 1" off the ground it did have a tendency to scrape the ground during normal driving so I trimmed an inch off of it to give a little more clearance. The deflector was mounted to its own bar which was mounted to the cradle so even if something hit the deflector, it would not have a chance of damaging the IC core unless it bounced up into the IC. In all the years I’ve run my (smaller) IC under my Fiero I’ve never had anything bounce up and damage the core in it. If I remember correctly, I think I got that air deflector off an 80's GM RWD car.
With a little more modification, an air-to-air IC with a larger core could probably be fitted in the same location. Is it the best location for one on a car? No. The best location would be up in front of the radiator, but there is no room to run charge air piping up to it on a Fiero unless you want to make some serious modifications to the chassis. The second problem is with the radiator and a/c condenser being up there already, it is crowded so there really isn't room for an air-to-air IC; nor a heat exchanger core for a water-to-air system…at least not enough to work as effectively as they can anyway.
Working with any Fiero is always going to be compromise. There isn’t as much room in these cars as most of us would like to be able to do the things we would like to do to them. Sure you can delete the A/C system and give yourself more room but I don’t consider that to be a viable option since I (and many other people) want working A/C. Even if you deleted the A/C, you still have an inherent airflow problem thru the radiator area due to the stock design of the front-end of the Fiero (which you cannot easy change without doing some rather radical body mods).
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Originally posted by Justinbart:
I never get more than a 16* temp rise with my air to water. That is unheard of with an air to air.
I would be curious to know exactly how you took your temperature measurements (what you used to take them and where these sensors were located) and if you also took inlet and outlet pressure readings so you could get an overall efficiency rating of the IC system you were using. Simply saying you only had a "16 deg" temp rise doesn't really tell us much. I do not doubt what you are saying but more data is needed to draw accurate conclusions.
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Originally posted by darkhorizon:
The plastic L36 intake has been proven to be a great performing intake... and pressure tests to well over 100PSI without issue.
I have ran a plastic intake on multiple turbo cars for years now without a single issue, and dyno proven power.... I dont see why these wannabees are coming into this thread saying you need to have an aluminum one.
I don't know if I would trust an original factory L36 plastic intake. They like to crack on stock non-boosted engines, and when they do, they can dump coolant into the intake (albeit from EGR operation). Granted, an updated design plastic intake was made available later that was supposed to fix this problem but the chance of finding one in a junkyard is going to be slim and it is difficult to distingush between the two designs just looking at them. I would be concerned about the durability of that plastic when it is heat cycled + sees the wild pressure swings it is going to see in a turbocharged application. Given how many problems GM had with this plastic intake makes me question how DURABLE it will be in the long run when used with a turbo. Besides that, they don't look the greatest. If someone is going to use a FWD N/A intake, I would recommend they at least use the all-aluminum L26 intake which looks better. But the Camaro/Firebird intake looks the best, in my opinion - and it works good too. Bottom line here is you are never going to need to worry about an all-aluminum intake manifold cracking. So which one is best? That's always going to be a subject for debate since nobody wants to spend the time or money to do all the testing that would be required to prove one better than the others for every possible engine operating scenario.
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Originally posted by Englishrafe:
Good input from all of you. However, I'm a couple of months away from buying any of the intake system - so we'll talk plastic, aluminium, left/right facing, air/water, air/air, mounting position etc... once the engine is back on the subframe (cradle).
What are your ideas about compression ratio? Bearing in mind that in Europe I can fill my car with 95 or 98 grade fuel, should I consider going to the highest comp ratio pistons available? The 9.5:1 ones. Is this pushing it a bit with iron heads ? What are you running ? 8:1? 8.5:1? 9.5:1? Yes I know we'll come back to the inter-cooler question, but lets just say that there will be good inter-cooling.
I do have a little experience with turbo engines having raced a Renault 5 Gordini Turbo in the past. This car was not inter-cooled (draw through carburettor) and in order to boost higher, we used to decompress the engine with a thicker head gasket down to about 7.5:1. However, this made bottom end response rather sluggish. But wow did that thing fly once the engine hit 3500 rpm and the turbo really started to boost! For the Fiero, I would like to avoid burning out my tires in 4th gear at 110km/h because the turbo kicks in super hard and uncontrollably! (I remember Justin's write-up of a similar experience.)
I think that keeping a reasonably good atmospheric phase of the motor with higher compression is the way to go. Not exploding my Getrag with shock loading would also come into the equation!
Rafe
It depends on what you want to do with your car and what kind of fuel you are going to be running. The stock 3800 SC 8.5:1 static compression ratio seems to work good with the fuels we can get here in the States. You can run a decent amount of boost on 93 octane (our rating) pump gas (with an intercooled turbo setup) and then really crank it up when you dump some 110 octane fuel in. A higher static compression ratio will give your engine better off-boost performance, but this can limit the amount of maximum boost you will be able to run for a given octane of fuel which will ultimately limit the amount of total power your engine can make.
-ryan
[This message has been edited by Darth Fiero (edited 02-24-2012).]
Originally posted by Darth Fiero: I would never mount an IC like that. I think you are asking for trouble (the real possibility of something hitting and damaging it). Did you have electric fans mounting on this IC that you had hanging on there like that?
-ryan
I put the intercooler in that position to test the validity of having an intercooler in that location, after driving nearly 500 miles with more than 90% of it on the hwy between FL and GA and seeing pretty much the same inlet temps (with my IAT sensor mounted just before the throttlebody) I saw no reason to have it on the car at all as it was a greater contribution to increased weight than intercooling. If at 70 mph there's not enough air moving underneath the car to make a significant difference, how much more moderate city driving. That 6" tall core is hanging more than 2" in the expected air stream, it's more like 4". the core is 3.5" thick and 18" long.
The core facing the expected air stream is the most effective positioning and wouldn't require fans at all which would only be effective at speeds low enough to allow them to pull more air through the core than is already flowing, after that there is a risk that they may impede flow if a speed is reached where air is attempting to pass through the core faster than the fan can pull it.
Your intercooler arrangement as well as one other I saw with the intercooler angled is what inspired me to test the arrangement. If hardly enough air is moving under the car to make an impact with the intercooler hanging directly in the theoretical air stream, I can't see where an air dam in the same location will make any difference attempting to direct already non existent air 90 degrees upward into an intercooler which is a less favorable position than what I setup temporarily and so far no one has come forward with any proof (data or experience) to the contrary.
It appears I'm the only person with an IAT sensor placed just before the throttlebody and after the intercooler in order to know for sure if such an arrangement is productive. When I mounted the intercooler up front my inlet temps dropped by at least 100 deg, I posted before and after logs of those results in my 3900 build thread. I didn't post any logs on the above arrangement because I have no reason to lie about it and the fact I removed it from the car altogether should be proof enough it was worthless in that location.
There should be liquid radiator cores in appropriate dimensions available to do a great job up front depending on how much boost you intend to run and once again the heat transfer in this system should be very good even with small cores if the performance of the cars heater core mentioned earlier is any indication. I believe the fact that engines are water cooled instead of air cooled is a good indication as to how effective liquid to air cooling is as well. Ever lay on a cold water bed? I bet it'll kill you you from hypothermia if you can manage to fall asleep on one
It will be some time before I get the intended kit, install and report what I find.
[This message has been edited by Joseph Upson (edited 02-24-2012).]
I would be curious to know exactly how you took your temperature measurements (what you used to take them and where these sensors were located) and if you also took inlet and outlet pressure readings so you could get an overall efficiency rating of the IC system you were using. Simply saying you only had a "16 deg" temp rise doesn't really tell us much. I do not doubt what you are saying but more data is needed to draw accurate conclusions.
I have the IAT sensor half way between the intercooler and the TB. After several miles of driving it will read 10-12* over ambient then an additional 16* during a long run under high boost. So if its 70* outside it will say 70* and eventually clime to 82* while cruising and 98* under boost. Then it falls back to 82* after 20-30 seconds. I'm not sure if scott has any scans of the IAT. I just watch it on the Scanmaster. I don't have an IAT sensor before the intercooler but FWIW I can tell you that the hot side is too hot to touch and post intercooler is cool to the touch.
If you are only going to be running 88 (R+M)/2) octane then I wouldn't go over stock compression. I loved having 9.4:1 in the L26 engine but I was also running E85 which is 105-110 octane. ------------------ Turbo3800E85 5spd spec5 11.54@132.7
[This message has been edited by Justinbart (edited 02-24-2012).]
Originally posted by Darth Fiero: Granted, an updated design plastic intake was made available later that was supposed to fix this problem but the chance of finding one in a junkyard is going to be slim and it is difficult to distingush between the two designs just looking at them.
Actually, it was the lower intake manifold that was redesigned. It had a smaller diameter stove pipe for the egr. The smaller pipe allowed for a larger air gap between the pipe and it's recieving bore hole in the plastic upper manifold. This hole is where the manifold would get brittle, break open to a water passage behind the throttle body and induce coolant into the intake. In some cases, this would hydro-lock the engine on start-up and bend connecting rods. The larger air gap kept the hot egr stove pipe from deteriorating the plastic upper manifold.
here on Base the fuel pumps show the Germany octane rating and the US rating. German 98 octane = US 92 Octane. I'll double check this next time i fill up my tank.
It's cost more but why not top mount like a rx7 or a Subaru, it's not ideal but it should work better than putting it under the car. you would have to modify your deck lid but it would be sweet. and forgive me it's an mr2 photo
It's cost more but why not top mount like a rx7 or a Subaru, it's not ideal but it should work better than putting it under the car. you would have to modify your deck lid but it would be sweet. and forgive me it's an mr2 photo
SHUN! :P
I was thinking an efficient way to use an intercooler would be to change the way air flows through the engine compartment. it goes from bottom up, taking out the heat via the decklid vents. Instead of having air come out the vents, pump air into them via side scoops or roof scoops. Also for this to work, you must modify the rear of the car to include air vents to create a suction on your engine compartment. If you design them right, you have constant airflow through the engine compartment, and some cool looks! You however might lose some trunk space. Then you can position the intercooler(s) under the scoops to have ram air into them.
Only downside is, if you do not design the outlet vents right, you overpressure your engine compartment and underside of the rear of the car, producing some lift and also minimalizing airflow inside of the engine compartment, leading to... lots of heat.
[This message has been edited by Racing_Master (edited 02-24-2012).]
That looks cool (no pun intended!) the high mount IC. However, in France my car needs to stay fairly original looking in order not to attract too much "cop" (Gendarme) attention. I know of a '79 Firebird that got impounded during a car meeting because of it's huge hood scoop! The guy had to thumb a lift home as the Gendarmes took all the papers and imobilised the car - no way you can talk your way round a determined (mean!?) Gendarme !!
For Tweeter: Do you know of the military base near Torgelow in norhern Germany? Apparently, that's where my motor came from.
I forgot to take photos of the final drilling. Heres the finished valley area with it's 8mm holes. This is copied from what I've seen on the net concerning the preparation of these types of engines.
After which, I gave the block a "five minute" grind over to remove sharp edges, casting flashing and generally smooth out all internal areas for oil flow and the exterior just to make it look nice !
Still have to plug the balance shaft oil hole. I will probably do it with a small grub screw tapped into the block. Something for later on...
At the end of the day I started on one of the heads. Not too much progress, just smoothed up one combustion chamber:
Here's a close-up of the head - kind of before and after when you compare the two combustion chambers:
I think it looks pretty no ?
These heads are light-years ahead (in terms of design) of my oldsmobile heads in my Trans Am! It's going to be so easy to get them up to scratch. Only trouble is time - probably won't get to do any more before next week end now. (long sigh.......!)
I put the intercooler in that position to test the validity of having an intercooler in that location, after driving nearly 500 miles with more than 90% of it on the hwy between FL and GA and seeing pretty much the same inlet temps (with my IAT sensor mounted just before the throttlebody) I saw no reason to have it on the car at all as it was a greater contribution to increased weight than intercooling. If at 70 mph there's not enough air moving underneath the car to make a significant difference, how much more moderate city driving. That 6" tall core is hanging more than 2" in the expected air stream, it's more like 4". the core is 3.5" thick and 18" long.
First off, the way you explain you had it mounted tells me that there probably wasn't even airflow hitting a full 2" of your 6" tall IC core. So I'm not surprised at the results you got. You need to understand that there isn't much air flow right up against (or even within 1" of) the bottom of the Fiero's chassis. The bulk of the air flow is going to be more than 1" away from a given surface like this.
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The core facing the expected air stream is the most effective positioning and wouldn't require fans at all which would only be effective at speeds low enough to allow them to pull more air through the core than is already flowing, after that there is a risk that they may impede flow if a speed is reached where air is attempting to pass through the core faster than the fan can pull it.
Not true, at least not in the environment we are talking about here. You are basing your assumption on the scenario of a core mounted on the front of a vehicle – in which case you WOULD BE CORRECT in your statement. But, airflow dynamics under a car are much different than what the very front of a car encounters (see my previous paragraph). Based on the fact that less air flows under the car than what the very front of the car encounters makes the presence of a fan that more critical when an IC is mounted in back.
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Your intercooler arrangement as well as one other I saw with the intercooler angled is what inspired me to test the arrangement. If hardly enough air is moving under the car to make an impact with the intercooler hanging directly in the theoretical air stream, I can't see where an air dam in the same location will make any difference attempting to direct already non existent air 90 degrees upward into an intercooler which is a less favorable position than what I setup temporarily and so far no one has come forward with any proof (data or experience) to the contrary.
I guarantee you there is a lot of air moving under the car any time the car is in motion – at least on a Fiero that sits at or near stock ride height. Your post suggests there is very little air moving under the car and I have to say that statement is incorrect. Don’t believe me? Get some airflow sensors with remote displays and do some testing. I bet you are going to be surprised at the results.
The way you had your intercooler mounted under the car in the picture shows me it would in fact NOT be very effective. I can see in your picture that there is just too much space between the sides and bottom of the IC for air to move around it instead of thru it. The fact that you also did not have any fans at all mounted to that IC further explains why that IC didn't do a thing for you. I'm not surprised you got the results you did. I could have told you before you even put it on your car the way you did (in the picture) you would have gotten very poor results; so I could have saved you the trouble.
I think some of you people fail to understand airflow dynamics as well as what the importance of having an airdam is. If you don't understand what I am trying to explain here, then there is a simple test you can do on your own Fiero that will demonstrate what I am talking about. Go out and unplug your radiator fan and also remove the factory airdam from under the core support. Now drive the car on a 70 deg or warmer day and tell me what happens to your engine's coolant temps after some driving. I bet you are going to find your engine runs hot and probably wants to overheat regardless if you are moving down the freeway at a good clip or if you are sitting still.
The function of the airdam is 2-fold. 1) It directs some air to flow up into the area just above and ahead of it, and 2) it creates a lower pressure zone behind it that helps draw air down from the comparment above and behind it. If you go look at just about any GM car that has a small grill area, I bet you are going to see an airdam of some kind hanging under the core support. There is a reason why GM put these on their cars and I can tell you from personal experience the cooling systems in these cars do NOT work well without them.
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It appears I'm the only person with an IAT sensor placed just before the throttlebody and after the intercooler in order to know for sure if such an arrangement is productive. When I mounted the intercooler up front my inlet temps dropped by at least 100 deg, I posted before and after logs of those results in my 3900 build thread. I didn't post any logs on the above arrangement because I have no reason to lie about it and the fact I removed it from the car altogether should be proof enough it was worthless in that location.
Take the airdam off your Fiero and disable the electric fan. Then re-run your tests with your water-to-air IC and let me know what happens. I bet you are going to be surprised.
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Originally posted by Justinbart:
I have the IAT sensor half way between the intercooler and the TB. After several miles of driving it will read 10-12* over ambient then an additional 16* during a long run under high boost. So if its 70* outside it will say 70* and eventually clime to 82* while cruising and 98* under boost. Then it falls back to 82* after 20-30 seconds. I'm not sure if scott has any scans of the IAT. I just watch it on the Scanmaster. I don't have an IAT sensor before the intercooler but FWIW I can tell you that the hot side is too hot to touch and post intercooler is cool to the touch.
In order to run an accurate temperature drop test you would need at least two properly calibrated IAT sensors; one installed between the turbo and IC and one between the IC and TB (it would also be best to have a 3rd mounted near your air filter between it and the turbo's inlet so incoming air temp could be measured). Just having one installed and giving you readings from one point doesn't tell us much. I've seen factory IAT sensors provide wildly inaccurate air temp readings vs. actual outside temps. I'm not saying this happened to you during your test, but it is a possibility. Also, if you want to know the efficiency rating of your IC, you would also want inlet and outlet pressure readings in addition to the charge air temp readings.
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Originally posted by Racing_Master:
the way air flows through the engine compartment. it goes from bottom up, taking out the heat via the decklid vents.
This is the natural tendency of airflow thru the engine compartment of a Fiero. My IC placement puts the IC right where air naturally wants to enter the engine compartment on a Fiero. Adding the airdam forces more air from under the car up into the engine compartment (and thru the IC core).
Actually, it was the lower intake manifold that was redesigned. It had a smaller diameter stove pipe for the egr. The smaller pipe allowed for a larger air gap between the pipe and it's recieving bore hole in the plastic upper manifold. This hole is where the manifold would get brittle, break open to a water passage behind the throttle body and induce coolant into the intake. In some cases, this would hydro-lock the engine on start-up and bend connecting rods. The larger air gap kept the hot egr stove pipe from deteriorating the plastic upper manifold.
Then why were there updated upper plastic plenums sold for L36 engines? I bought such a plenum from Napa years ago and it came with a paper explaining the design change (IE: coolant ports moved closer to EGR pipe hole and an enlarged EGR pipe hole so the actual EGR pipe was further away from the plastic - in that particular design anyway).
Originally posted by Darth Fiero: I think some of you people fail to understand airflow dynamics as well as what the importance of having an airdam is.
Not to provoke argument but, I trust my experience over your speculation here. I honestly believe this is more of a not wanting to be wrong about anything issue for you than actual fact. You have a rebuttle for everyone's concern in support of your own theory/assumption or belief here Darth. Just post some data to back it up, that'll help us all. That's the only way you'll get me to believe the intercooler and airdam arrangement you posted is actually more effective than letting the intercooler hang in the supposed air stream that your airdam is supposed to direct 90 deg upward through that intercooler. It looks great as far as the install, but I highly doubt it performs anywhere near as good as it looks. Am I to assume the factory airdam at the front of the car conditions the air in a manner to further enhance the second one you added down stream from it?
Another plus for the air to water intercooler is the fact that it was installed from the factory on the Syclone and Typhoon and the radiator for that system appears to be small enough to fit up front in the air stream in the same location I installed my intercooler out front. If I recall correctly it's also in use on at least one or more current GM muscle cars.
For the others who are "hijacking" this thread for the airflow discussion - please keep it "on topic" !
I would still like feedback on the compression ratio question - polishing the combustion chambers will take off a small amount of materiel (ie lower the comp ratio) but the smoothness (along with less carbon deposits) should help the burn caracteristics.
I will measure the cc of a polished comb chamber compared to the stock one. Then I'll dig out my comp ratio formula and do the maths. The question remains, should I buy the 9.5:1 pistons ?
Originally posted by Englishrafe: For the others who are "hijacking" this thread for the airflow discussion - please keep it "on topic" ! Rafe
Sorry about that but understand, you cause confusion when you start a thread with a question;
"Europeen style 3800 turbo swap - what do you think ?" "Intercooler - thinking of a water/air unit with a secondary radiator up in the front."
I don't think it's a hijack at all given the above, certainly not intended. The discussion is directly related and relevant given the above two quotes. If I'm wrong in my stance on the subject in question, you should probably consider the arrangment Darth posted instead of the water air unit if you're still thinking about it.
I am keeping in mind all the info on inter-coolers - just haven't got that far yet.
Rafe
No offense taken, Darth probably does more tuning than anyone on the forum and should have data from some of the intercooled arrangements he has come in contact with to confirm what he's stating but as of yet has not posted any. We've had this discussion before and I'm still waiting to see supporting evidence because without an intercooler my inlet temps run as high as 180 deg at 7psi and that's a power loss you can feel among other side effects so the info is important. If he's correct I'll follow his lead but I doubt it in this scenario.
I believe the Supercharged Caddi and Corvette run liquid to air intercoolers in addition to the Syclone/Typhoon pioneer vehicles.
I finished one head this week-end. Here are a few photos:
Intakes, exhausts and combustion chambers nicely poilished up.
Didn't alter the exhaust port shape, just polished the conduit up to a nice finish.
Cutting a 3-angle seat - this top photo is 70° and this one's the 30° cutter. I will be fitting new valves when they arrive.
So here is one head pretty much ready and waiting for it's hardware:
That's the end of the work for this week-end. Only another 15 hours with the mini-grinder for the other head - my hands are knumb with the vibrations! How do the guys who do this for a living survive?!
That is very true, I'm sure those cast iron heads are quite heavy. I do like the idea of drilling those oil holes in the lifter valley, seems like a good idea for better oil drainage, however I'm concerned it would create an area prone to cracking under high stress loads if someone didn't counter-sink to remove the edges.
Originally posted by mattwa: I do like the idea of drilling those oil holes in the lifter valley, seems like a good idea for better oil drainage, however I'm concerned it would create an area prone to cracking under high stress loads if someone didn't counter-sink to remove the edges.
I just copied what I've seen done by professional engine builders - I'm sure they wouldn't do it if the block became weaker? By the way, the metal thickness at that point is only about 5 or 6mm and yes the holes are counter sunk. I can't imagine that these holes would set off stress fractures - it's not like you just drilled through a complex part of the casting. At least I hope not!!
[This message has been edited by Englishrafe (edited 03-04-2012).]
Originally posted by Englishrafe: I just copied what I've seen done by professional engine builders - I'm sure they wouldn't do it if the block became weaker? By the way, the metal thickness at that point is only about 5 or 6mm and yes the holes are counter sunk. I can't imagine that these holes would set off stress fractures - it's not like you just drilled through a complex part of the casting. At least I hope not!!
Yea, I understand that, guess I'm just paranoid. If I did something like that it would crack and blow-up. But I didn't know it was so thin in that area, thanks.
Yesterday I measured the combustion chambers volume. I wanted to see if my polishing had altered to a large degree the volume?
I compared the head finished last week with the one I'm working on this week-end. Here's the technique:
Put a set of valves and a sparkplug back into the finished head, then cut a piece of smooth plastic (old 5 litre can) to cover the chamber in question. Light grease as a sealant between the plastic and the head - the blue colour on the plastic.
A piece of plywood as backing held down lightly with a couple of clamps. There are two small holes drilled near the top - one to inject the water in and one that lets out the air out. Measure the amount of water injected just untill water appears from the second hole.
Do the same as before to an unfinished chamber in order to compare the difference.
My seringe is accurate to the nearest cc.
The results are as follows: Unpolished chamber volume = 60cc Polished chamber volume = 61cc
Have you guys ever measured the heads? If so, what are your readings ?
Today, I am going to finish polishing the second head. Then a bit of maths to calculate the static comp ratio.
Interesting build. I wasn't surprised to read that his series 1 had "chewed" a piston and pin. I have an ex-minivan S1 motor sitting in my basement with exactly the same symptoms! That's why I'm going S2 - can't beat floating pins for load spreading!
I've just been doing the maths to find out my effective comp ratio. I ran the numbers with the different pistons available and keeping the standard head gasket thickness.
Since I will be running this car as (nearly) a daily driver I want something that has good performances "off cam/boost". I also understand that with 95 grade fuel (available here), I don't want an effective comp ratio above 12:1 (13:1 at a pinch ). (I can always put 98 grade or some other additive in for the race day.)
I calculated that my polished combustion chambers give a static comp ratio of 9.28:1 when using off the shelf "9.5:1" pistons with 4cc dishes. So at different boost levels,I get these results: 10psi boost = 11.43:1 12psi boost = 12.28:1 15psi boost = 13.54:1 20psi boost = 15.65:1
This means that I confirm that I'm going to buy the "9.5:1" forged pistons and keep the boost "lowish" for everyday use!! Yes!!
[This message has been edited by Englishrafe (edited 03-12-2012).]
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