Your 4.9 might seem fast, and have plenty of torque at 3000 RPM, but you are not going to spank any real Vettes with it.
I have had very few people in a C5/6 even look my way sitting at a light. Its not that don't like to race, your just not worth the time. Kind of like when a beat up import pulls up beside you
Heck they wont even give me a wave when I am driving the C4
I have the actual chart on my home computer. Unfortunately I do not have and will not install the picture uploader.
That's great. But none of those charts I posted are hosted on fiero.nl either. I just found them in google image search. You can use http://myfiero.com/imagehost.php to upload it instead of installing the VB app. Or you can upload it to imageshack/photobucket/dropbox/ubuntuone/wherever else you prefer instead. Not sure why you think the app is required to show pictures on this site.
Dobey you really make an art out of making useless points.
quote
You can see how much broader/flatter the torque curve is on the 3800. If you take your 4.9 car, and a stock L67 Fiero, and raced them from a roll at 3000 RPM, the L67 car would leave you behind. You might get a quick jump forward from the higher torque output at that RPM with the 4.9, but the L67 would quickly pass and leave you.
I wasn't saying the 4.9 builds better power than the 3800sc. What I was saying is that the carb'd 4.9 has a different power curve, and more power because it is not set up for emissions. I don't know what the hp is.
Generally speaking, if you are racing any NA engine against a boosted engine and you start at 3000 rpm, the boosted engine will have its best performance while the NA engine will likely have no advantage.
In the case of the stock 4.9 it does not make as much hp as the 3800sc and the performance of the two is well known.
I could have installed a 3800sc. I didn't want to. I enjoy playing with carb'd engines.
Originally posted by Jake_Dragon: I have had very few people in a C5/6 even look my way sitting at a light. Its not that don't like to race, your just not worth the time. Kind of like when a beat up import pulls up beside you
Heck they wont even give me a wave when I am driving the C4
Heh. Well, a *lot* of people have Corvettes, even if they aren't the type of people to pull off hard from a stop. Everybody and their brother around here either has a Vette, or a Mustang. I've seen so many 40-50+ year old women driving new Vettes, it's not even funny. And they're probably not going to bother racing you. And a lot of them don't want to lose the car they still haven't paid for yet, so don't want to risk getting caught street racing. In several states, it's guaranteed loss of license on the spot. Not great to have, if you've got a mortgage and a $70K car to pay for.
And my beat up import (which is still totally stock, save the muffler a previous owner put on it), is definitely faster than my 2.8 Fiero. Less TQ, but it's a lighter car, and the TQ curve is quite broad since I can spin it out to 8500 RPM, and the VTEC gives it more air after 5000.
…unless I ever get this LS4 swap finished and running.
Originally posted by Arns85GT: Dobey you really make an art out of making useless points.
I wasn't saying the 4.9 builds better power than the 3800sc. What I was saying is that the carb'd 4.9 has a different power curve, and more power because it is not set up for emissions. I don't know what the hp is.
Generally speaking, if you are racing any NA engine against a boosted engine and you start at 3000 rpm, the boosted engine will have its best performance while the NA engine will likely have no advantage.
In the case of the stock 4.9 it does not make as much hp as the 3800sc and the performance of the two is well known.
I could have installed a 3800sc. I didn't want to. I enjoy playing with carb'd engines.
The points I am making are only useless in your own little world. They are completely relevant to what the OP asked. If you would stop trying to talk past the points I'm making, it would help.
Nobody asked what you wanted to install. You've already installed what you wanted to install. The OP asked for information about some engines so that he could make a better choice about what he wants to install.
You're the one that's making the useless points in this thread. Your preference for playing with carbs is irrelevant to what will give the OP the best bang for his buck. Instead of telling the OP to just go with my preference, because it's what I prefer, I tried to ask the OP for more information about what he prefers, and provide information relevant to that data.
Dobey, Ed asked about a swap on a budget. He wanted to know whether going with 3800sc or v8 for less than $1500.
Fair enough.
I posted what I know to be the case for a carb'd 4.9. Cheaper by far than a carb'd sbc.
When you say
quote
The 4.9 valvetrain can't make the power, and starts falling short in the 4000-5000 range.
You really don't know what you are talking about. The valve train operates just fine to 6000 provided you don't increase the lift with a cam, and provided you are naturally aspirated.
When I say it pulls hard to 6000 rpm you seem to think I'm an idiot and can't tell what an engine is doing when I drive it. A car that gets lazy after 5000 rpm I know all about. This engine doesn't do that.
Sure the OE 4.9 starts falling off after 4,000 rpm. But it is not the fault of the valve train. It is the fault of the fuel delivery system and emissions equipment.
Ed wants a good solid and reliable swap. A straight up 4.9 or 3800sc with the ECM's and wiring harness will do that. So will the carb'd 4.9. Now you have to know that the carb requires a whole different approach and that may not be everybody's cup of tea. But it is a good option for a guy on a budget. For commuting though, I might stay with the EFI system for convenience, however the old EFI parts can be unreliable at times.
But I can tell you once it is running, the carb'd engine is a whole different animal to the OE 4.9
[This message has been edited by Arns85GT (edited 07-13-2013).]
You really don't know what you are talking about. The valve train operates just fine to 6000 provided you don't increase the lift with a cam, and provided you are naturally aspirated.
When I say it pulls hard to 6000 rpm you seem to think I'm an idiot and can't tell what an engine is doing when I drive it. A car that gets lazy after 5000 rpm I know all about. This engine doesn't do that.
Sure the OE 4.9 starts falling off after 4,000 rpm. But it is not the fault of the valve train. It is the fault of the fuel delivery system and emissions equipment.
If it pulls strong to 6000, then lets see the numbers. Find a dyno of a 4.9 with the only change being the conversion to carb. No valvetrain or cam changes.
Here's the one Zac88GT posted back in 2006:
It's definitely not pulling hard to 6000. A little better than stock, yes, but it's still dropping off past 5000. I'd say it'd pull ok to 5300 maybe, but definitely not to 6000. That was with a 500 cfm carb too. Maybe a smaller carb would do a bit better.
The "fuel delivery" and "emissions equipment" on the 4.9 doesn't make that much difference in power, from what you will get with a carb on the same engine. And what exactly are those "fuel delivery" problems, and "emissions equipment" that you're referring to? Please be specific. You're only knowing how to work on carbs isn't sufficient data to back up your claim. Please post actual data about what specifically is a failure on the stock motor, that somehow swapping to a carb and throwing the electronics out, solves. There is absolutely no amount of tuning you can perform on a carbed 4.9 that you can't also perform on a stock EFI 4.9.
And I guess you think Zac88GT has no idea what he's talking about either?
quote
Originally posted by Zac88GT: My carbed 4.9 pulled strong but certainly not to 6k, 4.5-5k maybe, but after that it was pretty pathetic. There must be something wrong with your centerforce clutch, mine held just fine with the carbed 4.9 and 100hp shot of nitrous.
Anyway, I'm not trying to say your 4.9 isn't fine for what you want out of the car. But I don't think it's the best match for what the OP wants out of a swap. I think the 3800 SC (L67) would be the best match for what he wants, and gives the best option for upgrading it in the future.
Like I said, I don't know if I'm going to dyno it.
The chart you posted is off a G-tech unit. I will likely be using a real dyno machine, much more accurate.
That said, I don't know if he was using a mechanical dizzy or still on the ECM. I don't know what carb setup he had either. I know the Rochester I had on it was not as peppy as the Holley I now have.
He also talked about both a Gehtrag and an auto. I don't know which he was running at the track when did this G-tech run.
I discussed the valve tree weakness with a qualified Cadillac mechanic and so far I have not opted for the Allante steel valve tree. They just don't fail all that often. I might yet, depending on finances.
Like I said, I don't know if I'm going to dyno it.
The chart you posted is off a G-tech unit. I will likely be using a real dyno machine, much more accurate.
That said, I don't know if he was using a mechanical dizzy or still on the ECM. I don't know what carb setup he had either. I know the Rochester I had on it was not as peppy as the Holley I now have.
He also talked about both a Gehtrag and an auto. I don't know which he was running at the track when did this G-tech run.
I discussed the valve tree weakness with a qualified Cadillac mechanic and so far I have not opted for the Allante steel valve tree. They just don't fail all that often. I might yet, depending on finances.
I seldom go to 6000 in any event.
Yes the chart is from a G-tech so the overall numbers may not be all that accurate (G-tech read 242hp with my northstar and dynod 305hp on a dynodynamics) but the shape of the graph certainly will be. That was with a mechanical distributor ~34-36* total advance, a brand new holley 2300 500cfm 2bbl, and the getrag 5 speed.
So due to the broader curve of the 3800sc it has a better top end. And with the better torque of the 4.9 it has a better low end. So for someone looking to do an autocross centered build the 4.9 sounds like the better candidate due to not really needing a huge top end on a road course? Am I right in thinking this? I would think that I don't really need to pull high rpms since the straight aways are short. This would be with an auto transmission that comes with whatever engine is swapped if that matters. I'm trying to keep the build cheap and with the 4.9 being cheaper and the ability to skip a lot of wiring with the carb, etc I would be inclined to choose it if it will achieve better course times. I'm not OP, btw.
So due to the broader curve of the 3800sc it has a better top end. And with the better torque of the 4.9 it has a better low end. So for someone looking to do an autocross centered build the 4.9 sounds like the better candidate due to not really needing a huge top end on a road course? Am I right in thinking this? I would think that I don't really need to pull high rpms since the straight aways are short. This would be with an auto transmission that comes with whatever engine is swapped if that matters. I'm trying to keep the build cheap and with the 4.9 being cheaper and the ability to skip a lot of wiring with the carb, etc I would be inclined to choose it if it will achieve better course times. I'm not OP, btw.
Thanks, -Josh
Wiring is so not an issue for either swap. It really is down to a plug and play science. Just order the right harness and call it a day. They are much cheaper now than ever before. When I did my first 4.9 swap, my harness set me back $700. Granted, it was 100% new, but still! Anyway, I can not emphasize this enough. The 4.9 has really ran its course. Its just not feasible anymore now that the 3800 is so popular. The only way I would go with a 4.9 is if I found a mint, low mileage, donor and got it for stupid money.
Originally posted by OneSlowFiero: So due to the broader curve of the 3800sc it has a better top end. And with the better torque of the 4.9 it has a better low end. So for someone looking to do an autocross centered build the 4.9 sounds like the better candidate due to not really needing a huge top end on a road course? Am I right in thinking this? I would think that I don't really need to pull high rpms since the straight aways are short. This would be with an auto transmission that comes with whatever engine is swapped if that matters. I'm trying to keep the build cheap and with the 4.9 being cheaper and the ability to skip a lot of wiring with the carb, etc I would be inclined to choose it if it will achieve better course times. I'm not OP, btw.
Thanks, -Josh
Might as well just stick with a 2.8, or go with a 3.4 pushrod swap if you want to keep the power in the low end while driving. They've got basically the same torque/power curve as a 4.9, and even easier to swap in. The 4.9 just makes a tad more torque/hp than they do.
The torque curve on the 3800 sc is broad and smooth. It doesn't mean it is good for high-end use. It means that the power doesn't just fall off a cliff soon after peak torque is hit.
An Ecotec would probably be the best swap to do, for mainly autox use. They're small and light, and can make plenty of power on a broad curve, as well.
The passions expressed here are obvious. And despite all the bias bickering, there is a lot of really useful information and opinions shared. I'm probably still leaning towards the 3800sc, and that was my original plan. There just seems to be too much info and mods available for it. I can live with the supercharger whine. And I think with the right exhaust, it will have a good sound. I just wish I could locate a decent one for about $500 - $800. LOL
I will look into the 3.4 pushrod swap. Thank you all for the information. It is to my understanding that once you do an engine swap of any kind that you are put into a higher racing class. If this is true then the 3.4 may not be enough. I have some more reading to do for sure which is fine with me because I have some money to save up
Originally posted by Zac88GT: Yes the chart is from a G-tech so the overall numbers may not be all that accurate (G-tech read 242hp with my northstar and dynod 305hp on a dynodynamics) but the shape of the graph certainly will be.
I disagree about the shape of the graph. I ran a "Road Dyno" back in '03ish. It's a recorder that makes an audio recording of the output of an inductive pickup on a plug wire. A computer program then processed that recording to get the engine's acceleration rate. Plug in gear ratios, tire sizes and vehicle weight and it estimates power. It's like a primitive G-Tech.
HOWEVER, neither the Road Dyno nor the G-Tech have ways to *ACCURATELY* back out aerodynamic drag at high vehicle speeds. This will cause both to dramatically under report top-end power... this DOES change the shape of the graph, as it effectively convolves the horsepower and torque traces with the inverse of the aerodynamic drag trace.
The Road Dyno user's manual outlined some methods to use the road dyno to measure coast-down acceleration and attempt to back out aero drag from that. HOWEVER, that's only good for the stretch of road on which you chose to test and your test run's wind conditions.
For $1500 you can do a cheap, bare bones swap. Buy a wrecked car, use every thing from it. drive it till the wheels fall off.
Beat a vet? NO!
I have a sbc. it pulls past 6000 rpm. It sounds like a cammed up V8. It has a chevy block, rods, and dizzy. Pistons, roller cam, intake, headers, exhaust, alum heads, roller rockers, valve springs, retainers, keepers, carb ( 650 ), air cleaner, are ALL aftermarket. So it realy isn't a "Chevy V8" It is a "HOTROD V8" Way, way more than $1500. try 6 or 7 times that. My son has a 3800SC ser 2 / 4T65, 3.29 gears, ported, springs, ZZP cam, headers. He just ran 13.45. My v8 car scares him. ( when i can get it to run )
you get what you pay for
It will do that from a slow roll in 2nd also. Needs more tire. If I had to do it for $1500 I would spend your time, a lot of time, looking for the right doner car that would have every thing you need. And make the rest. Do it. drive it. Go pick on vets with the drive line after that one.
Originally posted by Will: I disagree about the shape of the graph. I ran a "Road Dyno" back in '03ish. It's a recorder that makes an audio recording of the output of an inductive pickup on a plug wire. A computer program then processed that recording to get the engine's acceleration rate. Plug in gear ratios, tire sizes and vehicle weight and it estimates power. It's like a primitive G-Tech.
HOWEVER, neither the Road Dyno nor the G-Tech have ways to *ACCURATELY* back out aerodynamic drag at high vehicle speeds. This will cause both to dramatically under report top-end power... this DOES change the shape of the graph, as it effectively convolves the horsepower and torque traces with the inverse of the aerodynamic drag trace.
The Road Dyno user's manual outlined some methods to use the road dyno to measure coast-down acceleration and attempt to back out aero drag from that. HOWEVER, that's only good for the stretch of road on which you chose to test and your test run's wind conditions.
True, the g-tech user manual recommends using the data from 2nd gear to reduce this error. The run above was taken from third gear data though so it will be a little skewed.
No, there was a thread on it a few months ago.. that thing was about as broken as you could get.
Simple fact is, you can hang with c5's vettes with a $500 3800 swap. It doesnt take much from there to mod a 3800 in a way to leave them in the dust. I refused a race with a "800whp twin turbo" vette in town just because I didnt want to hurt the poor guys feelings as he just lost a race to a lambo....
if you did the "right" SBC swap you could get close to a c5, but it wouldnt be possible for $500.
It looks like I am back to my original plan of using the 3800SC.
It sounds like the mileage isn't a concern, especially if it's from a Buick. Just need to change all the gaskets. Of course clean it up too. Might also change the Supercharger pulley, etc.
There is a guy near me that has a 3800SC series II, Transmission, Wiring harness, etc from the donor car. Says only has 60,000 miles. Pulled for a sawp and never completed it. Says has video of it running in donor car before pull. He is asking $1200 for all of it.
Just got back to thinking about V8's after having, for a while, written them off due to fuel consumption.
Fact is, my fathers C6 with an LS2 (no DoD) and automatic transmission consumes less fuel than my auto 2m4 at 55-65mph, if my calculations are about right. Apparently, 30+ mpg is not uncommon for modern vettes on the highway. And when you think about it, there's nothing strange about it. It's all down to transmission ratios. The C6 will do what, 1000-1500 rpm @ 65mph? And our cars, something like 2500rpm? A V8 does not necessarily need to consume more fuel (until you floor it but that's pretty much true for any car, even my 1.4 Renault), you just need the correct transmission. For automatic transmissions there seem to be good alternatives from GM, for manuals I would look closely at transmissions like those out of the volvo "DrivE" models (since they seem to run a more mpg-oriented gearing, 1500rpm@60mph if I wasn't misreading yesterday). Of course, there aren't any kits for those alternative manual transmissions but still, maybe something is available for the fiero 4- and 5-speed transmissions to alter the ratios?
Just got back to thinking about V8's after having, for a while, written them off due to fuel consumption.
Fact is, my fathers C6 with an LS2 (no DoD) and automatic transmission consumes less fuel than my auto 2m4 at 55-65mph, if my calculations are about right. Apparently, 30+ mpg is not uncommon for modern vettes on the highway. And when you think about it, there's nothing strange about it. It's all down to transmission ratios. The C6 will do what, 1000-1500 rpm @ 65mph? And our cars, something like 2500rpm? A V8 does not necessarily need to consume more fuel (until you floor it but that's pretty much true for any car, even my 1.4 Renault), you just need the correct transmission. For automatic transmissions there seem to be good alternatives from GM, for manuals I would look closely at transmissions like those out of the volvo "DrivE" models (since they seem to run a more mpg-oriented gearing, 1500rpm@60mph if I wasn't misreading yesterday). Of course, there aren't any kits for those alternative manual transmissions but still, maybe something is available for the fiero 4- and 5-speed transmissions to alter the ratios?
With the G6 F40 transmission, you're going to be at about 1800 RPM at 65 MPH on stock size tires. With the tallest final drive of the 6t75 (2.77), You'll be doing about 68 MPH at 1800 RPM in top gear. The 2.77 gear might only be available in the Ford version though, and I don't know if the Ford diff is directly swappable into the GM 6t75. You'd have to do some research on that. But the F40 is widely used in LSx swaps into Fieros, and the 6t75 has been used on one, and requires an expensive transmission controller. However, the C6 Vette also probably has a lower CD than the Fiero does, so you will see a slightly lower MPG in the Fiero than in that Vette.
Just got back to thinking about V8's after having, for a while, written them off due to fuel consumption.
Fact is, my fathers C6 with an LS2 (no DoD) and automatic transmission consumes less fuel than my auto 2m4 at 55-65mph, if my calculations are about right. Apparently, 30+ mpg is not uncommon for modern vettes on the highway. And when you think about it, there's nothing strange about it. It's all down to transmission ratios. The C6 will do what, 1000-1500 rpm @ 65mph? And our cars, something like 2500rpm?
The LS4/F40 swapped into my 88 Fiero pulls down 29 mpg at 70-75 mph and 20-22 mpg for my daily 19 mile commute. It also puts down 382 whp (about 420-430 fwhp).
With the G6 F40 transmission, you're going to be at about 1800 RPM at 65 MPH on stock size tires. With the tallest final drive of the 6t75 (2.77), You'll be doing about 68 MPH at 1800 RPM in top gear. The 2.77 gear might only be available in the Ford version though, and I don't know if the Ford diff is directly swappable into the GM 6t75. You'd have to do some research on that. But the F40 is widely used in LSx swaps into Fieros, and the 6t75 has been used on one, and requires an expensive transmission controller. However, the C6 Vette also probably has a lower CD than the Fiero does, so you will see a slightly lower MPG in the Fiero than in that Vette.
yup, the vette certainly has better aerodynamics and will have an advantage due to that, just saying that with proper gearing the bad mpg argument against the V8 can pretty much be taken out of the equation (unless we're comparing to the modern turbo-diesel engines, but we usually aren't)
The 6T75 is a very interesting alternative I'd say. With 6 gears at least the problem of never having a suitable gear is out of the way. I'm not really updated, is the 6T75 used in a FWD V8 application already? or is the LS4 + 4T-something the only factory option available at this time? Anyway, if it's not available as a complete unit it hopefully will be :-) The F40 seems to be a good alternative for those needing to stay with (or convert to) a manual transmission.
Originally posted by PerKr: yup, the vette certainly has better aerodynamics and will have an advantage due to that, just saying that with proper gearing the bad mpg argument against the V8 can pretty much be taken out of the equation (unless we're comparing to the modern turbo-diesel engines, but we usually aren't)
The 6T75 is a very interesting alternative I'd say. With 6 gears at least the problem of never having a suitable gear is out of the way. I'm not really updated, is the 6T75 used in a FWD V8 application already? or is the LS4 + 4T-something the only factory option available at this time? Anyway, if it's not available as a complete unit it hopefully will be :-) The F40 seems to be a good alternative for those needing to stay with (or convert to) a manual transmission.
The 6t transaxles are not mounted behind any V8s from factory, no. There's a thread in the Construction Zone where one was used behind an LS2 in a Fiero to develop the standalone controller at PCS, though. The LS4/4t65e-hd is the only FWD LSx based V8 that was ever in a production car. There's also the Northstar+4t80e combo as well though.
With the right engine and transmission, the MPG isn't going to be too bad, but it's still a valid reason for someone to not go with a V8. Sure you might be able to get 30 MPG or so with the right combination, but with the right Ecotec and transmission combo, you can be getting 50 MPG.
Fuel economy has very little to do with the motor, and everything to do with the weight and aero dynamics of the car. A car requires xxx horsepower to push it, and as long as a 10L motor can make that little of horsepower with reasonable efficiency, its going to not require any more fuel (technically) to do so. The only factor that comes into play is the amount of friction inside of the motor while it is running that lends to high or low gas mileage.
Fuel economy has very little to do with the motor, and everything to do with the weight and aero dynamics of the car. A car requires xxx horsepower to push it, and as long as a 10L motor can make that little of horsepower with reasonable efficiency, its going to not require any more fuel (technically) to do so. The only factor that comes into play is the amount of friction inside of the motor while it is running that lends to high or low gas mileage.
By that definition, the ZR1 should be pushing 40 MPG, not barely breaking 30, on the highway. But it's not that simple. More cylinders means more rotating mass, and more friction, which means more fuel. A larger tire contact patch means more friction, and more fuel. Even the C7 with direct injection, cylinder deactivation, and a 7 speed manual is only rated at 29 MPG highway.
If you want to argue theory, then sure, the engine can be made irrelevant. But in practice, the thing consuming the fuel is indeed a large part of the equation to fuel economy. There are five things you can do to improve fuel economy:
Less weight Improve aerodynamics Reduce contact patch Gear ratios (including tire size) Tuning the engine
More cubic inches equals more pumping loss are small throttle openings, one of the larger losses with a high cubic inch engine making small power. Larry
Originally posted by dobey: With the right engine and transmission, the MPG isn't going to be too bad, but it's still a valid reason for someone to not go with a V8. Sure you might be able to get 30 MPG or so with the right combination, but with the right Ecotec and transmission combo, you can be getting 50 MPG.
definitely, it all depends on the goal of the swap and the compromises chosen. 50 MPG is fun in its own kind of way and even most fuel economy oriented swaps will have equal or better performance than what came in our cars from the factory anyway. So yes, the consumption is still a reason not to go with a V8 (depending on what swap you're comparing it to), it's just not necessarily as bad as a lot of people think. And it certainly depends on what you want out of your swap.
Originally posted by PerKr: definitely, it all depends on the goal of the swap and the compromises chosen. 50 MPG is fun in its own kind of way and even most fuel economy oriented swaps will have equal or better performance than what came in our cars from the factory anyway. So yes, the consumption is still a reason not to go with a V8 (depending on what swap you're comparing it to), it's just not necessarily as bad as a lot of people think. And it certainly depends on what you want out of your swap.
Well a carbed first gen SBC is probably going to be as bad as people think for MPG. It's a very different engine from a modern LSx engine, which is also a bit different from a Northstar, Caddy 4.9, or an Audi V8. Comparing one specific V6 engine (3800) to a whole class of widely varied engines, based on one or two numbers, is just silly in itself.
It's too bad GM doesn't offer a small displacement V8 based on a mix between the LSx and their Indy Car engine, in anything. A 3.2L turbo V8 that turns 10K RPM would be pretty wicked in a Fiero.
