turboing 86 fiero gt

[robertisaar]

buy, borrow or steal it... cost me $35, but goddamn, i learned a lot.

I'm already going to deal with lag if I run that much pipin its going to add a bit more. Look at acura nsx's and toyota mr2s running a rear mount with a diffuser catches plenty of air to cool also remember I have an alky injection setup for it as well

robertisaar is correct and that's the point I was trying to get across that side by side a long distance intercooler system compared to a long distance turbo system all else the same will build boost quicker in part because of how far the energy that spools the turbo has to travel and the loss of effective spooling due to the cooling of the exhaust gases along the way causing them to contract. This phenomena has the opposite and positive effect on intake charge air over the same distance.

I didn't notice any increased lag with my front mount intercooler and I made it a point to do the math before conducting the experiment, I believe my results are in my build thread but the time to throttle body increase was such a small amount compared to what I stood to gain it was not a problem. My inlet air temps are now about 100 deg farenheit at ~8 psi on mid grade fuel down from 212 deg without an IC, that's good for about a 10% increase in power.

I'm going to convert it to rear IC because I don't have room for the proper pipe diameter to run the intended 15 psi over that distance and because I want to simplify the entire system for dependability, so I'll be moving away from the twin turbo setup also to a T72 or T76 single turbo with a .96 or more if necessary turbine housing. I also have a water/meth kit that hasn't been installed yet as well as 60 lb/hr injectors which is another area I forgot to mention to you may be a problem on a 2.8L if you can't pulse them low enough to avoid flooding the motor at idle since they are more than 3 times the flow ability of the stock injectors.
Although you mentioned other engines using the setup or similar to your plans, I believe all of them were more powerful and efficient than the 2.8L which means you are more likely to have too much supply for your engines demand which can be a problem.


Here is my car now with the front mount intercooler and cripplingly advanced camshaft that is likely cutting output by as much as 100 hp if CNCguy's estimate of 20 deg advance and my Dyno simulators estimate is correct. I'm going to degree it in to fix that.

Hope you succeed at what you have planned.

http://videos.streetfire.net/video/Testing-with-without_680592.htm

Proof of the front mount intercooler

http://www.fiero.nl/forum/Forum2/HTML/084972-5.html

[robertisaar]

lag is not the same as boost threshold. more piping will increase the threshold. lag is entirely dependant on engine tune and the turbo. retarding the spark 15* will spool the shit out of a turbo to get it up to speed. that's reducing lag.

[kikinz24]

I'm already going to deal with lag if I run that much pipin its going to add a bit more. Look at acura nsx's and toyota mr2s running a rear mount with a diffuser catches plenty of air to cool also remember I have an alky injection setup for it as well

im planning on pushing as much as the motor can handle . if it scatters ill tear it apart and rebuild it again. honestly my main goal it to attempt close to 500hp . plus fmic on a rear engine vehicle would not be efficient at all. honstly dont know the breaking point of this motor but if i could hook anywhere near 500 ill be the happest camper out there lol

Why wouldn't a front mount intercooler be efficient keeping in mind rear mount turbo systems and the advantage a front mount intercooler has over that distance compared to a rear mount turbo since heat loss from intake charge is a good thing unlike heat loss on the exhaust side over the same distance.

[kikinz24]

im planning on pushing as much as the motor can handle . if it scatters ill tear it apart and rebuild it again. honestly my main goal it to attempt close to 500hp . plus fmic on a rear engine vehicle would not be efficient at all. honstly dont know the breaking point of this motor but if i could hook anywhere near 500 ill be the happest camper out there lol

[kikinz24]

http://www.squirrelpf.com/turbocalc/graph.php?version=4&pr0=1&pr1=1.05&pr2=1.59&pr3=2.12&pr4=2.12&pr5=2.12&pr6=2.12&pr7=2.12&airflow0=4.3&airflow1=13.6&airflow2=23.9&airflow3=36.3&airflow4=41.9&airflow5=45.2&airflow6=50.3&airflow7=53.4&product_id=124

this is approx what it looks like on there kinda generic but i guess it works. i know the ic dont change too too much but im still running it bc u dnt see it out there. also as i said in the past i got the turbo for only 400 dollars i cant even touch a brand new gt30-32 for that which is what i would originally go with size wise. so as it may be considered overkill it will definitly do the job properly. at hell 1/3 of the cost of the turbo i was going to go with.

goin with alot of port work to the heads. im running high boost its not guna be a daily driver of no means. i culd care less if i have to buy cam 2 for each run. i jus want this little car with a huge turbo. and yes i know its overkill. but itll be ok lol. anyhow all the turbo setups people are running are going non i/c im running a rear mount ic. with alky injection. i like doing what people tell me i cant do. i ran a super 60 on a 97z24 nobody said it would run. and if you ask anyone around town that car was f***N wicked. theres a guy on the fbody forums running a 72trim on a 2.8 and its pushing 412 hp. i know it is possible and plan on doing it. because i like the attention of HOLY S**T that turbo is HUGE. hell i got it jus chillen in the engine bay and my friends are like dude ur guna kill urself.....

i will make it fast or die tryin!

I don't believe anyone intends to discourage you, and there's nothing wrong with being different, it's just the numbers are not within reason for what you are planning to do. You purchased the turbo because it was an excellent deal, not because it is optimal for what you are trying to accomplish, that in itself is counter productive. 72 trim on a 2.8L doesn't say a lot without all of the specs. A super 60 is a T3 turbo which is what's being suggested. What are your power goals?

Why not put the intercooler in the front of the car for the best cooling ability.

[robertisaar]

squirrelpf.com/turbocalc

enter your setup in there and you'll see exactly why what you are trying to accomplish is a very bad way to do it.

there are LS motors using smaller turbos than the GT42... now something displacing twice as much volume and able to spin just as fast, but they use a smaller one, why do you think that is? its not because they're not running a I/C or any other reason: its the optimal turbo for the application.

[kikinz24]

have you ever seen the face of a 6 year old kid when a crotch rocket rolls by on 1 wheel. thats the look i go for with every one of my rides

[kikinz24]

goin with alot of port work to the heads. im running high boost its not guna be a daily driver of no means. i culd care less if i have to buy cam 2 for each run. i jus want this little car with a huge turbo. and yes i know its overkill. but itll be ok lol. anyhow all the turbo setups people are running are going non i/c im running a rear mount ic. with alky injection. i like doing what people tell me i cant do. i ran a super 60 on a 97z24 nobody said it would run. and if you ask anyone around town that car was f***N wicked. theres a guy on the fbody forums running a 72trim on a 2.8 and its pushing 412 hp. i know it is possible and plan on doing it. because i like the attention of HOLY S**T that turbo is HUGE. hell i got it jus chillen in the engine bay and my friends are like dude ur guna kill urself.....

i will make it fast or die tryin!

[robertisaar]

it is gigantic, it s a damn T6 framed turbo... i'm lining up a T3 for my 3900 plans and thats just BARELY undersized...

im completly aware that it is a extremly large turbo . and the motor is in no way stock. im using a 3.1 out of a 92 z24 total tear down. custom cam, p&p heads, lt1 springs. all forged lower end. 60# injectors walbro 255 adj fpr.. ill basicaly put it this way the turbo was on a vehicle for 3 weeks. a friend of mines truck he traded it in with the stock parts on it. i got the turbo for 400 bux and brand new it cost 2300. so i wasnt passing it up. been doing alot of reading and a vw with a 2.8 vr6 can get it to spool 15 psi at 3200 and 20 psi at 4100-4200. i know it sounds absloutly crazy to play with a 3.1 when i can upgrade to something else but im tryin to keep the car as stock looking as possible. im not running a evap system or egr system and i removed the cruise control setup. so i have the room for the turbo suprisingly. but its a toy for me and ive built a wicked 3.1 n/a in the past.

A chevy 2.8L is no VR6 by a long shot (especially moded) at about 20 hp less than the VR6 stock. If you plan on using cast iron heads that's another handicap. The GM 2.8L just doesn't move enough air under practical boost levels and unless you intend to run extremely high boost levels for a 2.8L the GT40 is to much turbo especially for around town daily driving. You will have to push it pretty hard before boost sets in and that's no good fun factor wise for around town driving. Let me get this straight, you want to keep the car as stock looking as possible with that GT40 tumor attached to it :-).

Quite a bit of turbocharging has gone on over at the Fiero Forum, you'll be the first I've ever heard of put a turbo that size on a 2.8L in a Fiero or 3.1L for that matter. A good example would be Dennis Legrua; 3.4L iron head motor, cammed possible light head work with a custom T3/T4 turbo probably putting out about 310 hp. He used to offer a kit at one time. At least start with a 3500 bottom end, it's already forged. I've lost count of how many 2.8L turbo Fieros I've built and can tell you first hand, change the turbo or the motor and save yourself an I told you so.

[TiredGXP]

Still seems like a big turbo for a gen II 3.1. The GT42 was what I may eventually use for the LS4...

[kikinz24]

im completly aware that it is a extremly large turbo . and the motor is in no way stock. im using a 3.1 out of a 92 z24 total tear down. custom cam, p&p heads, lt1 springs. all forged lower end. 60# injectors walbro 255 adj fpr.. ill basicaly put it this way the turbo was on a vehicle for 3 weeks. a friend of mines truck he traded it in with the stock parts on it. i got the turbo for 400 bux and brand new it cost 2300. so i wasnt passing it up. been doing alot of reading and a vw with a 2.8 vr6 can get it to spool 15 psi at 3200 and 20 psi at 4100-4200. i know it sounds absloutly crazy to play with a 3.1 when i can upgrade to something else but im tryin to keep the car as stock looking as possible. im not running a evap system or egr system and i removed the cruise control setup. so i have the room for the turbo suprisingly. but its a toy for me and ive built a wicked 3.1 n/a in the past.