I changed to SARD fuel pressure regulator long ago for higher boost. I am now going back to 7lb boost. However, I don't have the Comptech unit anymore... So, I am wondering what is the pressure setting on Comptech unit? I will just twist it to the Comptech setting to make it work, whoever knows it or whoever has the pressure meter, would you please share, thanks..!!

 

moving to FI

 

IIRC the Comptech is stock static pressure (47-54psi). But unless you're using injectors and an E-manage or similar you need an FPR with a rising rate ratio the same as the Comptech.

I wouldn't be making changes without some A/F monitoring.

And someone had a Comptech RRFPR for sale recently in the For Sale section. Might be a better option.

 

is the comptech fpr rising rate? if so, what's the fuel/boost ratio? thanks.


Kyle R

 

Of course it is. That's it's whole purpose. I'm not sure of the ratio but it's probably somewhere between 8 and 12 to 1.

 

AusS2000- Are you sure about that? Comptech was testing the Synchronic regulator I designed and their big gripe was that it wouldn't pull fuel pressure down to 35 at full vacuum at idle. They said that they needed to pull back that much fuel pressure to pass smog.

I think that their bypass orifice diameter is just too small for the Walbro 255.

 

About the pressure, or the ratio?

The pressure I double checked with Joe Sierro at Comptech when I installed mine.

As for the regulator being rising rate, it most definitely is as it's the only form of tuning used on the Comptech kit. Once pressure gets to ambient the ESM hides the MAP signal from the ECU and additional fuel is delivered by upping the pressure in the fuel rail. It does this by using the boost pressure on the FPR with a ratio so that for every lb of boost fuel pressure rises proportionally. It's only the ratio I am unsure of.

 

the thing is, I have the SARD unit already, don't really wanna spend extra money for the Comptech FPR, so, yup, that is what I will do. However, the number I get now will be a base line for sure, I will still put the A/F gauge on it to monitor the ratio. oh!! by the way, is B18-series engine using the same O2 sensor as ours?

for the 47-54 psi, are you saying that pressure is when the car is in idle and rpm stays around 1000 rpm?

 

No, it's static pressure. You remove the vacuum line from the FPR so it is seeing ambient pressure and set it to that range. At idle (vacuum) it will actually be lower (I guess that is what synapse is referring to). In boost it will be higher.

As for economising by not buying the Comptech, there is no sense in saving $50 if it costs you an engine. But if you have a current solution using the SARD and a smaller pulley then I assume you will be able to have a safe solution with a bigger pulley.

 

correct me if I am wrong since my English ain't as good as you guys. are you saying that with same pressure setting, it might result in different story since they are 2 different units??

however, for Comptech FPR, will it change the pressure when I am in the neture-gear and try to rev it up? if it doesn't, I will try to find my original comptech FPR, cuz I thought it was broken since it didn't change the pressue.