So how much gain or benefit are you looking at from installing this on your car? I know it's capable of delievering more fuel, but if your car's not tuned, wouldn't it defeat the purpose since the car is already running rich?

Thanks.

 

Yes, do not install it if you don't get it tuned. Mine ran like crap until tuned. Like the car was drowning in fuel, very unstable rough idle and loss of power in boost.

 

I think that it will vary from car to car. I installed mine and didn't have my computer tuned for it and my car ran fine and I'm getting better gas mileage than I was. It is probably safest to have you computer tuned for it though.

 

I put mine in when I had my exhaust, intake and MBC and it ran fine. 2 weeks after I installed it I got it tuned and it runs even better now

 

You won't see any gains (HP wise), but the benefit is more fuel delivery and lowering the injector duty cycles. There is also some risk in high temp climates of overworking the stock unit, causing it to fail and starve the car of fuel.

It's sort of like the ARP headstuds.. no gains, just safety.

 

Anyone with a Walbro have a fuel pressure gauge on their car? It sounds like the Walbro 255lph pump overruns the stock fuel pressure regulator, which is why some of you have driveability problems.

The proper way to increase the flow rate of your fuel pump is to upgrade the fuel pressure regulator at the same time as the pump to get fuel pressures back to stock specs. That way, the ECU won't need to be retuned to compensate for the offsetted fuel trims.

 

the stock regulator can handle it just matters on what type of tune you have. If you have an already rich tune then maybe t might affect it a lil bit. Other than that, the difference should be too small to notice.
if your car is completely stock i wouldnt do it. But when i did mine, i was hitting fuel cut like a *****. The car ran better and had a higher threshold for boost cut. Also i noticed much better gas mileage.

 

Can you define "can handle it"? What are base fuel pressures (with the vacuum hose off at idle) w/ the stock FPR and Walbro 255? Stock base fuel pressures are supposed to be 42-45psi according to the manual.

If you are retuning to fix driveability problems after installing a fuel pump, you are bandaiding the problem. The cause for driveability problems with an upgraded fuel pump can be caused by one of the following:
- higher than stock base fuel pressures
- non-linear rate of rise due to high flowing fuel pump overrunning the stock FPR

Increasing the fuel flow rate while maintaining the same base fuel pressure and rate of rise should not affect the injector duty cycles. The purpose of upgrading the fuel pump is to ensure that you have an adequate supply once boost is raised and demand is increased.