ok i have a couple of questions i am in the process of installing the nelson paxton s/c on my 88 convertible i have the walboro high flow fuel pump and 550cc injectors in both primaries and secondaries,i am getting the rising rate cartech fuel pressure regulator with a fuel pressure guage.what should i be adjusting the fuel pressure to i just need a general idea to get me to the dyno for tuning i also have the Apexi S-AFC so i can adjust it a little bit with that,what kind of ratio should the FPR be?thanks,Dave

 

How much boost are you planning on running? Unless you are keeping it pretty low (<10 psi) you might need to upgrade the injectors.

Sorry I can't answer your question on the pressure though.

 

the injectors are already upgraded to 550 in pri. and sec. this is a NA thats going S/C i will probably only hit 12psi. max boost. the 550 in all four is just a safety measurement i can always tune it down with the s-afc.

 

Does your cartech unit have the allen keyed stud with a nut on the top center and a a little bleed off valve on the top side with vacuum connection on the other top side?

 

I havent ordered it yet im ordering it in the morning it will be the latest one that cartech makes part# car-2025 its the fourth generation of the cartech FPR its at http://www.cartech.net/fmu2020.htm

 

When you start adding up the price of this unit and a s-afc then figuring out how to modiffy the timing under boost, you realize why many of us are running after market engine management systems. The prices of used units are now under a thousand dollars. There are many units out there such as WOLF, TEC #, Haltech, Micotech and more. Every year they are coming out with newer and better units and you will see older units turning up at bargain prices.

 

yes i would love to upgrade to a haltech but the lack of experience with one and dont know anyone who has one and also rewiring the car.I already had the S-AFC,i just ordered the cartech rising rate FPR i may really not need it but when i rebuild the motor and s/c i ifgure i will probably want more boost,i rather be safe than sorry,i will upgrade to a haltech one day just not now.Thanks,Dave

 

I love the haltech units. You would need a laptop. There are other units. There is an older unit out there that would work real well with your boost range and you would not need a laptop. All you would probably need is a pair of bigger injectors and I assume you allready have a fuel pump. This is a "Wolf 3D verion 3". There was a member on this list running 10s with this unit on a street turboII over 3 yrs ago.

Info on Cartech:
The cartech unit is made to work on the return line coming from the stock unit. Make sure you set the big nut on the vortech such that the pressure is bellow the stock unit. This will allow the stock unit to maintain the correct fuel pressure during not boost driving. The small bleeder valve should be totalling locked on your first try in the boost condition pulling through a gear. You want it to be rich. If it is not rich , then either your fuel pump is not up to the task of the injectors are still to small. If it is too rich you can adjust the bleeder to lean it out.

Good luck.