Yes, the pump is overrunning your FPR, causing you to run rich, wasting gas. Get an AFPR or swap a walbro 190 pump in, then you won't need an AFPR.

weith1111 said:

Yes, the pump is overrunning your FPR, causing you to run rich, wasting gas. Get an AFPR or swap a walbro 190 pump in, then you won't need an AFPR.

Click to expand...

I'll agree for the most part, and damn your fast on the keyboard.

The only discrepancy I have is the statement regarding the 190 pump. IMO any fuel pump upgrade should have an upgraded FPR along with it. I know many will flame me but my thought is that most just take it for granted that it works fine, but I believe you should take every precaution when modifying a car to insure that everything is working to the best of it's ability in order to increase reliability. The orifice in the OEM FPR is just too small for any real pump upgrade.

FORMONTOYA said:

I'll agree for the most part, and damn your fast on the keyboard.

The only discrepancy I have is the statement regarding the 190 pump. IMO any fuel pump upgrade should have an upgraded FPR along with it. I know many will flame me but my thought is that most just take it for granted that it works fine, but I believe you should take every precaution when modifying a car to insure that everything is working to the best of it's ability in order to increase reliability. The orifice in the OEM FPR is just too small for any real pump upgrade.

Click to expand...

Point taken, it's possible you would even see benefit from an AFPR on an OEM pump, opening any restriction helps, even if you aren't pushing the limits. Deposits and such can be reducing the size of the openings, although I'm sure the engineers probably design for a certain amount of overage to begin with...

I have been told an AFPR is NEVER necessary, by EXTREMELY reputable tuners and shops, it just "makes tuning easier." I believe that to be garbage, just because you have your car running well doesn't mean it's safe and a repeatable practice. In that regard, there are many a dsm running around with no AFPR and a 190 pump, so I think it's not a requirement. But, like you said, it's better than not having it.

weith1111 said:

Point taken, it's possible you would even see benefit from an AFPR on an OEM pump, opening any restriction helps, even if you aren't pushing the limits. Deposits and such can be reducing the size of the openings, although I'm sure the engineers probably design for a certain amount of overage to begin with...

I have been told an AFPR is NEVER necessary, by EXTREMELY reputable tuners and shops, it just "makes tuning easier." I believe that to be garbage, just because you have your car running well doesn't mean it's safe and a repeatable practice. In that regard, there are many a dsm running around with no AFPR and a 190 pump, so I think it's not a requirement. But, like you said, it's better than not having it.

Click to expand...

Now I can agree with the clarification.

I'm just an anal type of guy that goes for reliability over peak/perceived performance in order to achieve longevity out of my dollars.

Just like to add to this, Ive got a 255lph walbro right now, and you KNOW the engine is running like crap, theres a pop in the exhaust at idle constantly and you can smell the fuel in the exhaust, not only that, but the fuel dilutes your oil too. I just ordered my AFPR last night, take heed.

weith1111 said:

Get an AFPR or swap a walbro 190 pump in, then you won't need an AFPR.

Click to expand...

MOST people don't have any fuel overrun issues with a 190 pump and if they do it is not as bad as the 255. The assumption that you won't need an AFPR with a 190 is not correct because some people with 190s had to get an AFPR for their car. It depends on car to car.

FYI - Oldman corrected me on this... a few weeks ago.

DGajre777 said:

MOST people don't have any fuel overrun issues with a 190 pump and if they do it is not as bad as the 255. The assumption that you won't need an AFPR with a 190 is not correct because some people with 190s had to get an AFPR for their car. It depends on car to car.

FYI - Oldman corrected me on this... a few weeks ago.

Click to expand...

Once again, NEED and BENEFIT FROM are two different things. I drove with a supra pump and no AFPR for YEARS. AND managed above 20mpg, AND managed a 13.7 timeslip on a s16g, the pump and a MBC. Was my tailpipe black? Yes. Could I manage a wicked backfire? Yes. Did I need an AFPR? Obviously not because I made it to work everyday. My car would have appreciated one though, and I could have added another 3-4 mpg and knocked a few tenths off the quarter mile.

The idea that it "depends on car to car" is not correct logic. The issue is the flow of the pump is too much for the overrun passage. So unless your 190 pump flows less than my 190 pump, or your stock FPR has a bigger hole than mine, there should be no disputing this issue. The reason an AFPR isn't NEEDED is because the overrun is minimal. Bigger the pump the more overrun is needed, that's why with the 255's it becomes a "mandatory" mod to get an AFPR.

I've had this discussion with shops/tuners before, and even though what they say actually makes sense, it is not applicable to most people: if you can use the fuel, you don't get the overly rich situations. Think about it, the only reason you are running rich is because you aren't using the flow the pump is sending. The secondary problem is the overrun passage is too small so the extra fuel goes to the injectors too. If you ran 1500cc injectors, a 190 or 255 or supra pump wouldn't cause you problems...at WOT

This is where the "not applicable to most people" comes in. My car needs to idle, so this theory isn't going to work for me. I need all that fuel I'm not going to use to bypass the injectors.