im stuck between choosing a 3800 and a 4.9 im leaning towards the 4.9 just because its a v8 and all aluminum and im more of a handling person and i would like ot do some auto xing ive seen that someone turboed a 4.9 and of course if i did go 3.8 it would have to be turbo just for the efficency now some say 4.9s any where between flat 15 to almost a flat 14 and with a turbo so i guess input on handling for those who own (and honesty not bias and be nice lol) and which one will be cheaper and easier seems as though from what i read its going to be easier for the 4.9 i will have ot have most of the stuff fabbed mounts i should be able to do though and will be using what should be the getrag 5spd any input would be appreciated thanks

Its funny you say 4.9 or 3800 turbo because there was a thread a few months ago reversing the 2, because a 4.9 is really nothing compared to a 3800SC. The 3800 has efficency out the butt, and runs circles around any 4.9 out there, after a very slight amount of modding, the turbo 4.9 would have serious problems keeping up.

Do a search for the 4.9 turbo vs 3800 sc thread.

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[16:58] davepettinelli: mine's got a court-apponted psychiatrist
[16:58] davepettinelli: yay girls
[16:59] GTPimpin: mine whines alot
[16:59] GTPimpin: her name is fiero


Ultimate 3800 swap thread

3800 TURBO~!!! Ftw.

i actually did read it the guy ran a 12.2 in a 4.9 turbo i forget his name now but also take into consideration weight balance which i want to keep or even gain a lil front to rear and which one will be easier to install the 4.9 seems easier so more input welcome also ill get some pics here in about 15 minutes or so

Always the 4.9 haters, it's a shame.

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88 Coupe: Modded 4.9L V8 5 speed
87 Coupe: 4 Cyl 5 Speed
84 Coupe: 4 Cyl 4 speed
01 BMW 525i
www.geocities.com/fast88fiero

ya with all the v8 hating you would think its a honda forum any answers from those who own both and whats more complicated to put in

The person who did the 4.9 turbo is PBJ here on the forum. Keep in mind they never reached the limit of the boost. They stopped it a 8psi because they were already hitting low 12's and to go any faster would have required a rollcage. That was not an option so that is as far as the 4.9 has gone so far. Here is the build thread for it.
https://www.fiero.nl/forum/A...060206-1-023354.html

Here is a 4.9 performance rebuild thread.
https://www.fiero.nl/forum/Forum2/HTML/061613.html

Here is a list of SC3800 threads.
https://www.fiero.nl/forum/Forum2/HTML/079560.html

Stop hatin' on the 4.9. Especially if you dont own one. Its a good, reliable motor and still hasn't reached its full potential.

stock for stock they are pretty close in performance. Up to 60mph the edge goes to the 4.9. After that the SC3800 takes it. The 3800 is ~ 100 lbs heavier so take that into consideration if you like to corner. 4.9 fiero=quick and numble, 3800=high speed screamer that never stops pulling

Drag motor- 3800
stoplight to stoplight- 4.9
Road course- 3800
low speed windy road/ autocross- 4.9
A turbo 4.9 is a whole other monster and I wont go into it. You can imagine an V8 with a nice lope, turbo wine, and a blow off valve.

This is my opinion and if you have a problem with something I said take it up in a PM to me and leave it out of this thread. There are enough trash can threads over this subject already.

[This message has been edited by Fieroseverywhere (edited 07-25-2007).]

quote Originally posted by Fieroseverywhere: The person who did the 4.9 turbo is PBJ here on the forum. Keep in mind they never reached the limit of the boost. They stopped it a 8psi because they were already hitting low 12's and to go any faster would have required a rollcage. That was not an option so that is as far as the 4.9 has gone so far. Here is the build thread for it. https://www.fiero.nl/forum/A...060206-1-023354.html Here is a 4.9 performance rebuild thread. https://www.fiero.nl/forum/Forum2/HTML/061613.html Here is a list of SC3800 threads. https://www.fiero.nl/forum/Forum2/HTML/079560.html Stop hatin' on the 4.9. Especially if you dont own one. Its a good, reliable motor and still hasn't reached its full potential. stock for stock they are pretty close in performance. Up to 60mph the edge goes to the 4.9. After that the SC3800 takes it. The 3800 is ~ 100 lbs heavier so take that into consideration if you like to corner. 4.9 fiero=quick and numble, 3800=high speed screamer that never stops pulling Drag motor- 3800 stoplight to stoplight- 4.9 Road course- 3800 low speed windy road/ autocross- 4.9 A turbo 4.9 is a whole other monster and I wont go into it. You can imagine an V8 with a nice lope, turbo wine, and a blow off valve. This is my opinion and if you have a problem with something I said take it up in a PM to me and leave it out of this thread. There are enough trash can threads over this subject already.

and only on 8 psi geez plus im going to only run the stock motor 1st just to get it goin before dumpin mass amounts of money in it how complicated is this ive been reading and all i see is some rewiring a different tranny/ motor mount exhaust and some cpu reprogramming btw who could i have do that what else am i missing

thanks joe

I would think for autocrossing, a 3800 would be better, I think it revs higher, and makes better power up high. A stock 4.9L does not rev very high, it makes lots of low end torque, which is good for accelerating at low speeds, but it could also break the rear wheels loose easier while cornering if you are too hard on the throttle, ending up in spinning on an autocross. I have autocrossed a few times, and having more RPM's is good so you can hold a gear longer. I have a Quad 4 HO, and at the same autocross course I did one year there was a 2.8L V6 with a 4 speed, and he was using 3 gears, while I was using 2 because I can rev 1000RPM higher, and hold a gear longer, when you are shifting you are not accelerating, so it hurts your time.

Also, with the 3800, there are more boost friendly parts out there like pistons and that, since there were factory boosted engines made. Also, since it is a V6, there will be more room in the engine bay for a turbo.

The 4.9 is an aluminum block with cast iron heads, where the 3800 is all cast iron. Wouldn't the 4.9L engine be top heavy with all the weight of the heads on top of the light block?

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84 Fiero Sport Coupe #1192 :: 86 Fiero Base Coupe Quad 4 HO :: 1998 Dodge Neon EX 2Dr 2.0L DOHC Auto

The weight difference is not that important IMO.... I think the advantages of the weight difference would the difference between a big guy and a small guy driving.

the 3800 just makes more power all over, it may peak less than a decked out 4.9, but the curves will never be close to each other IMO, mod for mod. Also, you get a small advantage of having cheap full out tunable engine manament.

I have the video of PBJ's 4.9 doing a quarter mile run and it is very impressive. There is plenty of room for a turbo with that engine because the intake feed is at the top of the engine instead of the side allowing you to move the turbo a little closer, and the shot of his engine compartment didn't appear to be any more crowded than other turbo builds I have seen.

He apparently had problems keeping an automatic transmission behind it. I know they're out there but I have not seen any 12s quarter mile posts among all of the 3800 SC Fiero swaps that have been posted on the Forum, so I don't think it's fair for the victory to go so easily to the 3800 SC that apparently would need more in the way of modifications to do what PBJ's 4.9 did. Heck among all the chevy swaps here on the forum I have not seen proof of the kind of performance he got out of that 4.9 from them either.
I believe 12.2s in the quarter makes a pretty good point in light of all the theories and assumptions.

[This message has been edited by Joseph Upson (edited 07-26-2007).]

quote Originally posted by Joseph Upson: I have the video of PBJ's 4.9 doing a quarter mile run and it is very impressive. There is plenty of room for a turbo with that engine because the intake feed is at the top of the engine instead of the side allowing you to move the turbo a little closer, and the shot of his engine compartment didn't appear to be any more crowded than other turbo builds I have seen. He apparently had problems keeping an automatic transmission behind it. I know they're out there but I have not seen any 12s quarter mile posts among all of the 3800 SC Fiero swaps that have been posted on the Forum, so I don't think it's fair for the victory to go so easily to the 3800 SC that apparently would need more in the way of modifications to do what PBJ's 4.9 did. Heck among all the chevy swaps here on the forum I have not seen proof of the kind of performance he got out of that 4.9 from them either. I believe 12.2s in the quarter makes a pretty good point in light of all the theories and assumptions.

Well my manual 4speed ran 12.6, that was completely stock with a 3.4 pulley. My perfectly identical auto swap is nearly as fast on the street, but hasnt been to the track yet.

11's would be very easy for me with this 3800 setup, possibly harder with the manual trans, I have faith in my auto that it would hold up for 11 second passes. If I put anywhere near the time and money that PBJ put into his 4.9, I dont doubt I can run circles around him.

quote Originally posted by Joseph Upson: He apparently had problems keeping an automatic transmission behind it.

When they installed the turbo they also installed a 4T60 with a shift kit. They did take out third gear at one point and replaced the tranny. My understanding is that they sold the 4.9 intact and never broke it. It was a very durable motor for what they used it for. This was after several seasons at the strip and hundreds of runs. Check out the last page in his build thread that I posted earlier. For those looking to do a turbo 4.9 keep in mind that they DID NOT use the stock 4.9 ECM. In fact they never used it at all. They used a 1227730 ECM. Its OK though because these ECM's are cheap, plentiful, and you can buy a wiring harness from Painless to work with it. You will also need to change out the throttle body to a type that that ECM can use.

the 4.9 defintly is more interesting to me but the fact that its been out of prouction for alost 14 yrs scares me a little and how long was it proudeced from until 94 also im not so sure about how hard it is going to be to go to obdII and whats the price difference roughly going to be and are the 3800 na still set up with boosted internals who knows i might do both eventually i have two fieros but i guess money and complicatedness (as if thats even a word lol) is big factors also and last but not least how high to i got to get the rear end to drop the motor from underneath seeing how i dont have a lift

thanks joe

quote Originally posted by fierogofast: the 4.9 defintly is more interesting to me but the fact that its been out of prouction for alost 14 yrs scares me a little and how long was it proudeced from until 94 also im not so sure about how hard it is going to be to go to obdII and whats the price difference roughly going to be and are the 3800 na still set up with boosted internals who knows i might do both eventually i have two fieros but i guess money and complicatedness (as if thats even a word lol) is big factors also and last but not least how high to i got to get the rear end to drop the motor from underneath seeing how i dont have a lift thanks joe

http://en.wikipedia.org/wiki/List_of_GM_engines
http://en.wikipedia.org/wiki/Buick_V6_engine#L26
http://en.wikipedia.org/wik..._engine#Aluminum_OHV
http://dtcc.cz28.com/
http://www.fieroaddiction.com/

[This message has been edited by Fieroseverywhere (edited 07-26-2007).]

lol thats an interesting way of doing it fieros everywhere ive also seen people put the fronts on ramps and lift the rear with a hoist ever tryed that technique before and thanks those links are pretty usefull still have to find prices on a tuned chip or ecu or piggyback style something also what do you guys got tied into your swaps the swaps dont make me that nervous till i get into boost which is kind of complicated

[This message has been edited by fierogofast (edited 07-26-2007).]

quote Originally posted by fierogofast: lol thats an interesting way of doing it fieros everywhere ive also seen people put the fronts on ramps and lift the rear with a hoist ever tryed that technique before and thanks those links are pretty usefull still have to find prices on a tuned chip or ecu or piggyback style something also what do you guys got tied into your swaps the swaps dont make me that nervous till i get into boost which is kind of complicated

Boosting is not complicated at all, boosting with a guestimated tune on a chip makes things complicated. The last I checked on a 4.9 more than a year ago I could get them in Florida for $300-350 all day long. The challenge comes with how much of the work you can do yourself. If you have all of the required tools you can do this swap rather easily and with minimal costs. It shouldn't take more than a cam regrind and a good exhaust to the turbo to get good performance from the 4.9 with a turbo. The 3800 is dealing with a supercharger and although they both make boost the dynamics are not exactly the same.

If I were forced to choose I would go with the 4.9 mainly because of the greater displacement and because of how much fuss I often see the 3800SC guys posting on the forum with troubles here and there that need to be figured out, and because to me the turbo is much easier to manage since it's not an integral part of the engine and turning up the boost a good bit does not require a pulley change, and as stated earlier, the turbo 4.9 did not fail at 8 psi, so perhaps another 2psi wouldn't compromise it any further and you'll have another 25-35 more horsepower from it.

Both are great swaps.

the actaul swap isnt going ot be the problem and i mean i can get stuff like brackets made just not flywheel stuff or anything like that if needed i know they stopped the 4.9 in 94 so how many years were they made and even if i went 3800 i prefer turbo due to the efficiency the simplicity of raising boost and the pretty little sound it makes down side is making a y pipe to fit it too so with this info what suggestions and don't u turbo4.9 guys have problems with stuff just exploding because of all the torque and is an ecu change needed for the 4.9