1989 3.8 turbo conversion

[ghettoboat]

I have been looking around for information on converting my engine but i havent found much. i really just need to know if it is feasible and what i am going to need to make the engine and computer system work.
The engine is currently in a 1989 riviera and that is probably where it is going to stay.

 

[b4black]

You may want to look into supercharging vs turbocharging. Since the '89 3.8 is an FWD/EFI motor, you may find more info in the 3800 SC forum, instead of Before Black. I'll move it there. If they can't help, maybe the Lounge will be th right place.

 

[Darth Fiero]

actually, I believe I can be of some help...

The 3800 vin C engine would be an excellent choice to turbocharge because it shares a lot of design characteristics with the GN's 3.8 with the exception of heads and oiling system among the most important.

My suggestion to you would be to track down some rods and a crank from a 1992-1995 3800 SC engine for your swap. The SC shares the same crank as what you have but is balanced differently to compensate for the heavier, beefier connecting rods. I also believe that the intake you have now, which should be similar to the GN intake, would be better for turbochagring than the later vin L 3800 TPI engines.

When turbocharging this engine, you might run into a snag pertaining to the stock throttle-body-mounted MAF sensor -- as it may not work with boost. However, I see no reason why you couldn't run a GN computer on this engine. The 3800's DIS module differs from the GN's unit but it should still be compatible with the GN computer.

One other advantage of the 3800 vs the 3.8 turbo engine is that the 3800's heads have a better port design in stock form. Exhaust systems between the 3800 and 3.8 will NOT interchange. A big disadvantage with the 3800 series 1 engines is the fact that no one (that I know of) makes aftermarket cams for them. The stock one is a billet roller design but I have not heard of many being able to re-grind these easily.

Hope this info helps.

 

[mikergp]

Darth,
I see you Turboed a Series II motor . Was this a naturally asperated motor or the SC version (VIN K or VIN 1)? What problems have you have and which ECM are you using?
Thanks in advance,

 

[Darth Fiero]

Originally posted by mikergp
Darth,
I see you Turboed a Series II motor . Was this a naturally asperated motor or the SC version (VIN K or VIN 1)? What problems have you have and which ECM are you using?
Thanks in advance,

I have not turboed on yet but I am in the process of turbocharging the car listed in my signature (that is what the * means ). I have a complete 97 vin 1 L67 motor sitting here ready to be gone through. It has a spun rod bearing so there is some work to be done. I plan on using the block, crank, pistons, and rods from the vin 1 engine and I have a set of ported L36 heads that are going on it. I am going to be using a camaro aluminum intake on this engine because I do not believe the stock L36 composite upper will handle the pressure. My fiero is currently running a 95 PCM that still has the removable prom and there is programming available for it which I have. The nice thing is that this PCM is already compatible with the LT1 maf sensor which I plan on using before the turbo so I am not putting boost through it or thru the one in the throttle body. I will keep you posted on my progress -- should be done by late spring.

 

[mikergp]

This sounds like a very cool project. If you get the rotating assembly balanced properly you can leave the balance shaft out of that motor as well, but you must plug the oil port to the back bearing. If you would like to go with a cam or any other parts you can't find let me know I can proly hook you up right up.
Keep me advised on the progress if you would,
Thanks,
Mike Dye

 

[mikergp]

OH I forgot as long as your this far into it there's coated piston's available as well.

 

[beyerch]

project

also, if you are going to use the series ii pcm (obd-ii & obd-i), i know of some people that can reprogram it to your needs as well.

 

[Darth Fiero]

The coated pistons look nice but I can't afford the $1000 price tag. I plan on leaving the balance shaft in place because it is really only there to even out firing pulsation oddities, not to balance any mechanical aspect. Besides, this engine won't be spinning hi RPMs so how much power is that little balance shaft going to sap anyway? I think not that much. I really don't have that much money to dump into this project at this time plus I don't want to push my luck with the 4T60-E trans that I have because my OBDI computer won't run a 65-E HD unit. So, until programming comes out for the OBDII systems that I can afford, I will stick to what I have now and see what I can get out of a nearly stock L67 that is turbocharged instead of supercharged. I think this project will yeild some interesting results.