I am currently building a turbocharger system for my 1988 GTA 350 TPI and was looking at the Car Tech FMU's. I was on their website and was wondering which FMU would fit. Any help is appreciated. TIA

Aftermarket Turbo and Supercharger (1/8 NPT) CAR-2025
Hi-Flow Aftermarket Turbo and Supercharger (1/4 NPT) CAR-2027

 

Mike from Car Tech just emailed me back:

Either one of those will work for your application. The 2027 has a larger inlet and outlet port.

Mike

Can anyone elighten me on this??

Which one is close to the size of the TPI return line??

 

I hope someone helps ya too . I need to learn more about the FMU's and stuff.

 

Im using a Malpassi fuel reg on the strong recommendation from the import crowd. Very happy with it so far.

 

I've been very happy with the Cartech FMU I've been running in my Z24. Its been daily driven for over 2 years and almost 28k miles with no problems. However, I did damage the first FMU by overtightening the center screw during tuning, which cracked the stainless diaphragm and caused constant high fuel pressure- but that was my fault, not a parts defect (FWIW, you can get a new SS diapragm from Cartech for a dollar or two). I wouldn't adjust the onset screw (center screw) to more than ~50psi to avoid this mistake I made. I have the Vortech Super FMU in my IROC, and I'll take the Cartech over the Vortech SFMU any day of the week.

Which size inlet/outlet? I'd just get the bigger one. Other than the outlet ports, they are identical. The reason you would want the bigger one is to allow a more serious fuel delivery system (pump) to be used. For instance, if you had a huge fuel pump that provided a lot of fuel, much of that fuel delivered by the pump would need to be bypassed back to the tank at idle to keep the fuel pressure in specs (very little of the fuel is going through the injectors at idle, so a large portion of the fuel put out by the pump needs to bypass through the return line and FMU back to the tank). If the fittings are too small on the FMU, they can restrict the fuel flow back to the tank through the return line, causing you to have excessive fuel pressure at idle (creating a rich condition). Personally, I see no reason to use the smaller fittings. I have the 1/4NPT fittings on my Z24 (PN 2027).

The Cartech instructions that come with the unit are great. FWIW, they are writen by Corky Bell, author of Maximum Boost (I believe Corky Bell owns Cartech- I talked to him one time when I called them).

 

Awesome!! Thanks for the great advice!! The 2027 is on it's way!