quote Originally posted by fierofan25: You also have to consider time. you can complete a 3800 build in about a week, some do it faster than that.Cost of a 3800 build can very from 1200$ to 3000$ depending on what you want it to look like when your done. As a DD it would be a great. Also 3800 engine are very strong and reliable.

If you know what you're doing, and either want to stick with an autoamtic, or already have everything else done to convert to manual, just waiting for an engine to bolt to it, then I might agree with that. But it's not as easy as you think, especially for people who have other responsibilities to deal with as well. Of course, you can ship your car off to someone who has done the install before, and pay them to do it, but your out-of-pocket will have doubled too.

quote Originally posted by Steel: Wouldn't a turbocharged motor be more efficient than the N/A because it's utilizing the exhaust energy (heat and flow) that's wasted on non turbocharged N/A motors?

Turbos are more efficient than superchargers. Putting a turbo onto an otherwise stock N/A engine doesn't make it more efficient. Now, let's say you custom built an N/A engine to put out the same amount of power as a stock engine with a turbo puts out. The "stock" engine with the turbo would probably get better fuel economy than the custom built one because the custom built one would probably need to be running a much bigger (than stock) camshaft and other performance parts in order to get that engine to produce the same amount of power as the turbocharged engine that has "stock" internals.

dratts: Concerning the durability question, I've seen a couple of Grand Prix GXPs around plus one or two that came thru my buddy's tranny shop that have turbo kits on otherwise stock LS4 engines. The turbo kits haven't been on these cars long and the engines are all starting to show signs of failing (massive blow-by, making noises, etc). So I don't think slapping a turbo on a stock LS4 is going to = what I consider to be a durable engine. Depends on how much boost you put on it, how good your tune is, and how much you beat on it. I'm going to say if you beat on it a lot, even if you are only running 6psi of boost or so, I wouldn't think it is going to last long. These engines just aren't designed for boost duty, and like everything else made by GM that is N/A from the factory, they used the cheapest parts they could get away with and ran very tight clearances to keep the emissions in-check. And neither of these are things you want when you put boost on an engine. But good luck to you and I hope you don't have any problems.

-ryan

Darth, sounds as though you've been around more of them than I have. Sure hope you're wrong though! Were the boosted ls4s that you are referring to using the cartuning kit? I was feeling a bit safer using a kit that has been installed on a couple of hundred cars and as far as I knew, no failures. Any information on a cartuning kit failure would be of great interest to me even though it might be a bit late.

[This message has been edited by dratts (edited 08-07-2011).]

quote Originally posted by dratts: Darth, sounds as though you've been around more of them than I have. Sure hope you're wrong though! Were the boosted ls4s that you are referring to using the cartuning kit? I was feeling a bit safer using a kit that has been installed on a couple of hundred cars and as far as I knew, no failures. Any information on a cartuning kit failure would be of great interest to me even though it might be a bit late.

The last Grand Prix GXP I saw with a turbo kit on it had a bone stock LS4 in it (as far as I was made aware) and it had a (then) "prototype" STS (at least I think it was STS) rear mount turbo kit on it. The engine produced tons of blow-by when it was just sitting there idling, and was starting to make some noises deep inside too. Not that many miles had been put on it with the turbo setup. But I was told it had been "pushed" a lot with the turbo.

The biggest problem with these stock engines is how the clearances are set up from the factory. GM has a habit of setting up all their engines with the tightest clearances (piston ring end gap, piston to cylinder bore, etc) as they can get away with because it improves emissions. The problem is when you put boost on one of these engines, you are exposing the pistons and rings to a lot more heat than they would normally see. And this increased heat will make those parts expand more than GM accounted for when they set up the clearances, which can give you problems (possible piston ring and piston ring land failure, possible piston scuffing the cylinder wall failure, etc).

So, in reality, it doesn't matter how strong the stock parts are if the clearances are too tight for the amount of boost you are putting on it. Something is going to fail prematurely. It isn't a question of IF, but just a question of WHEN. I don't care how good the tune is or how rich you are running it or how much timing you pull out. If you are putting too much heat on these parts for the clearances they were set up with, you ARE going to have problems. And don't think that by running a 160 deg t-stat or pulling it out completely is going to completely eliminate the risk - it won't. Running the engine too cold will increase wear and cause other problems as well.

Look, I know this is probably not what you want to hear. There are a lot of vendors selling "bolt on" turbo kits for all kinds of vehicles. But how many of them warranty your engine once you install the kit? Probably not a one. I don't doubt their claims that your engine could make XXX hp with their kit. If you turn the boost up high enough, it probably will. But for how long? And if it does blow up, how much you want to bet they are going to tell you there was something wrong with your engine? They might even tell you that they have an "in house" car that has "hundreds" of passes on it and it never had a problem so there must have been a problem with YOUR engine to begin with. How could you prove them wrong?

The bottom line is the junkyard core piles are littered with blown up stock engines that were pushed too hard by an aftermarket turbo, supercharger, or nitrous kits. I've personally seen people blow up engines that they pushed too hard for what they had done to the engine. It isn't a pretty sight. And the problem is: there is no way of telling how much boost your engine will take before something goes south. It depends on a lot of factors. All I can say is the absolute least I would do to a stock LS4 that a customer brings me who wants to put a turbo on it would be to hone the cylinders and file the rings to open up the clearances a bit in those 8 holes. I still wouldn't be crazy putting boost on the stock internals, but the added clearances would give some insurance when boost is added to the mix.

All I'm saying is I would exercise caution if I were you.

-ryan

[This message has been edited by Darth Fiero (edited 08-08-2011).]

I have done an LS4 and helped do a modified 3800SC manual. The LS4 is stock and has ALL of the options that it came with from the factory in the 06 Monte Carlo. By the way this is the first swap I have done with functonal A/C, I realy never "needed" it.
The 3800 was a monster and the drone from the exhaust was bad at freeway speed.
The LS4 is PERFECT for a driver. And I have to admit I HATE automatics, but it has enough power to pull it off fine.
The 3800 is not that "practical" in a highly modified form for daily use. The first gear is worthless and the monster power can use up the harder and harder to find Getrags.

I know this is hard to compare a highly modified manual V6 and a stock auto V8, but my opinion is that they both have great advatages and draw backs. It all depends on what you want the car to do for you.

I have a 6 speed F40 tranny for it, but have no idea when or if it will ever get put in.

quote Originally posted by Darth Fiero: I still wouldn't be crazy putting boost on the stock internals, but the added clearances would give some insurance when boost is added to the mix.

This is especially true on the modern GM engines, with hyperteutectic pistons which are designed to expand. Some of the Gen III LS engines would even cause noise similar to 'piston slap' when GM was using slightly looser clearances, as the piston could move slightly side-to-side when the engine was cold.

As Darth said, it's not a matter of if, but when. If you really want to run boost and make some power, get at least some forged pistons and maybe rods as well. And that doesn't include all the other oddities on a DoD/AFM engine.

quote Originally posted by dobey: And that doesn't include all the other oddities on a DoD/AFM engine.

I dont like the DOD on my LS4, it does not get that much better MPG anway, maybe 2-3mpg. Dont go out of your way to add it or keep it.
I drive in town in 3rd to keep it from going into DOD because the sound is nasty. It is kindof like an out of tune engine. And the feel is rough, like a VERY bad out of tune engine. On the freeway it is a little better but I still dont like it. I keep it in third when I give other people a ride just so they dont think the thing is running bad. It vibrates with the hard poly mounts that I have. It should be better if you use the fluid filled mounts.

quote Originally posted by Rickady88GT: I dont like the DOD on my LS4, it does not get that much better MPG anway, maybe 2-3mpg. Dont go out of your way to add it or keep it. I drive in town in 3rd to keep it from going into DOD because the sound is nasty. It is kindof like an out of tune engine. And the feel is rough, like a VERY bad out of tune engine. On the freeway it is a little better but I still dont like it. I keep it in third when I give other people a ride just so they dont think the thing is running bad. It vibrates with the hard poly mounts that I have. It should be better if you use the fluid filled mounts.

No, I have already deleted it for my swap, since I'm going to use an F40 behind the LS4. But the DoD/AFM hardware is quite complicated, adding a lot more potential failure points when wanting to go turbo. I would generally advise getting rid of it, if are doing any sort of performance build. It's too bad the LS4 never came with a manual. Would make swapping it with a manual easier, and would make it easier to get one without DoD.

quote Originally posted by Rickady88GT: I dont like the DOD on my LS4, it does not get that much better MPG anway, maybe 2-3mpg. Dont go out of your way to add it or keep it. I drive in town in 3rd to keep it from going into DOD because the sound is nasty. It is kindof like an out of tune engine. And the feel is rough, like a VERY bad out of tune engine. On the freeway it is a little better but I still dont like it. I keep it in third when I give other people a ride just so they dont think the thing is running bad. It vibrates with the hard poly mounts that I have. It should be better if you use the fluid filled mounts.

I don't doubt it would transmit a lot of vibration thru the chassis if you used poly mounts. I used rubber mounts in the swap I did and didn't have a vibration issue. But you are 100% correct on the exhaust note. With DoD active, it doesn't sound good.

quote The 3800 is not that "practical" in a highly modified form for daily use. The first gear is worthless and the monster power can use up the harder and harder to find Getrags.

NO engine is going to be "practical" in a "highly modified form" for daily use. Stick a big cam in your V8 and you'll have the same kind of problems.

I will agree the 3800 SC doesn't match up well with most of the available manual transmissions. But ANY engine that makes good low end torque won't match up well to a transmission that has a ridiculously low ratio for 1st gear. But that's not the engine's fault.

The LS4 swap I did had mildly ported heads, good exhaust, and good induction. With the stock auto trans, it ran a respectable 12.9 sec in the 1/4 mile. A 3800 Series 2 SC engine with an auto can do the same with a few simple bolt-ons; and at a much cheaper overall swap price than an LS4. If you want that LS4 to perform, you're going to have to tear into it and start replacing parts just like you would have to do with any other engine. And that's not cheap.

-ryan

quote Originally posted by Darth Fiero: GM has a habit of setting up all their engines with the tightest clearances (piston ring end gap, piston to cylinder bore, etc) as they can get away with because it improves emissions. The problem is when you put boost on one of these engines, you are exposing the pistons and rings to a lot more heat than they would normally see. And this increased heat will make those parts expand more than GM accounted for when they set up the clearances, which can give you problems (possible piston ring and piston ring land failure, possible piston scuffing the cylinder wall failure, etc).

That's process engineering... running as tight as the production tolerances allow for. In the aluminum block, I don't think that the piston to bore clearance is an issue, but ring end gap sure can be.
The engine's certainly not built for boost, but running it isn't necessarily the end of the world... If you keep the EGT's down and have adequate cooling system capacity, how hot can the piston possibly be? It's not the extra heat that kills the engine, it's the temperature. You can flow a lot of heat into an engine if you have the capacity to flow a lot OUT before getting the internal parts too hot.

quote Originally posted by dobey: This is especially true on the modern GM engines, with hyperteutectic pistons which are designed to expand. Some of the Gen III LS engines would even cause noise similar to 'piston slap' when GM was using slightly looser clearances, as the piston could move slightly side-to-side when the engine was cold.

Hypereutectics actually don't expand much. A "hypereutectic" piston is cast. It's cast with an alloy of aluminum that has added silicon beyond the eutectic concentration. Silicon has a lower coefficient of thermal expansion than aluminum. A high silicon aluminum alloy doesn't expand as much as a lower silicon alloy.
Fitting hypereutectic pistons to .001 in an aluminum block without having any engines blow up from piston scuff under normal use is quite a feat of process engineering. Avoidance of warranty engine replacements is one of the reasons that GM runs the clearances a little on the looser side. Inevitable production variations lead to piston slap if the clearances stack up on the loose side of the tolerance.

Thank you guys for all the information you're providing here. You're answering a lot of my questions and it's got to benefit other people who are trying to decide what engine to use and whether or not to boost. In my opinion a stock ls4 is a performer especially in a fiero. I've got boost because "too much horsepower is just about right".

quote Originally posted by Darth Fiero: NO engine is going to be "practical" in a "highly modified form" for daily use. Stick a big cam in your V8 and you'll have the same kind of problems. I will agree the 3800 SC doesn't match up well with most of the available manual transmissions. But ANY engine that makes good low end torque won't match up well to a transmission that has a ridiculously low ratio for 1st gear. But that's not the engine's fault. The LS4 swap I did had mildly ported heads, good exhaust, and good induction. With the stock auto trans, it ran a respectable 12.9 sec in the 1/4 mile. A 3800 Series 2 SC engine with an auto can do the same with a few simple bolt-ons; and at a much cheaper overall swap price than an LS4. If you want that LS4 to perform, you're going to have to tear into it and start replacing parts just like you would have to do with any other engine. And that's not cheap. -ryan

Maybe I should have noted that I also have four mounts around the bottom of the engine and no dogbone. The engine feels fine when it runs on all 8.
Extra mounts hold it down and in place, but maybe the dogbone keeps the harmonic vibrations in check?
Bottom line is that the engine does vibrate much more in active DOD mode, how the engine is mounted will control how much of that vibration the driver feels.
I have had the car at a GM dealer to have the ECM and all related systems tested and certified for the engine swap certification. No problems were noted and all systems functional.

[This message has been edited by Rickady88GT (edited 08-09-2011).]

quote Originally posted by Rickady88GT: Maybe I should have noted that I also have four mounts around the bottom of the engine and no dogbone. The engine feels fine when it runs on all 8. Extra mounts hold it down and in place, but maybe the dogbone keeps the harmonic vibrations in check? Bottom line is that the engine does vibrate much more in active DOD mode, how the engine is mounted will control how much of that vibration the driver feels. I have had the car at a GM dealer to have the ECM and all related systems tested and certified for the engine swap certification. No problems were noted and all systems functional.

The LS4 swap I did also had only 4 mounts (one in each corner); no dog-bone. But that was an 87 car that also had rubber cradle mounts. So there were two sets of rubber mounts there to soak up the vibrations. 1 set for the engine/trans and 1 set for the cradle. It DID help.

Running a dog-bone will make the vibrations worse, not better. That's because you'll be giving the vibrations a direct path to the chassis (they will be able to transmit directly from the engine to the chassis thru the dog-bone). Of course, if you have an 88 chassis, your cradle has no rubber mounts as it solidly bolts to the chassis, and that doesn't help with the vibration issue.

-ryan

My ls4 is 4 point solid mounted to an 87 frame. So far the only thing I notice is that my windshield rear view mirror shakes more than I would like.

quote Originally posted by dratts: My ls4 is 4 point solid mounted to an 87 frame. So far the only thing I notice is that my windshield rear view mirror shakes more than I would like.

Mine shakes as well, but only in DOD.
Is yours the same, or does it vibrate all the time?

Yeah, mine shakes the mirror all the time, even when I put my hand on it, although holding it makes it shake less. My side mirrors are ok. My dod is disabled. I've never driven it with dod enabled. You guys have convinced me that I don't want dod, and anyway I'm getting pretty good gas mileage without it.
I should add that my windshield is a 96 Nissan maxima and not a stock fiero windshield.

[This message has been edited by dratts (edited 08-09-2011).]

quote Originally posted by dratts: Yeah, mine shakes the mirror all the time, even when I put my hand on it, although holding it makes it shake less. My side mirrors are ok. My dod is disabled. I've never driven it with dod enabled. You guys have convinced me that I don't want dod, and anyway I'm getting pretty good gas mileage without it. I should add that my windshield is a 96 Nissan maxima and not a stock fiero windshield.

I dont want to change the subject, so if you will can you PM me or provide a link to a thread on the windshield?

[This message has been edited by Rickady88GT (edited 08-09-2011).]