AFPR tuning

Posted By: Jakub Kowalczyk

AFPR tuning - April 23, 2005 03:12 am UTC

I just installed my new Aeromotive AFPR. I set the base pressure to 36 psi, with the vaccum disconnected. It's at 27psi at idle with the vaccum reconnected.
I went for a ride, and noticed that everything is very lean. I have 660's with keydiver chip compensating for the injectors.
With the stock fpr I had the base setting leaned out two clicks (20cc) with the MAFT.
With the new AFPR I had to richen it up 4 clicks, which is a setting for 430's.
The fuel pump is a low pressure whinebro 190.
Is that possible?
I'll try to get pics of the install, maybe I fudged it up.
Posted By: Jonathan Largon

Re: AFPR tuning - April 23, 2005 08:35 am UTC

It would make sense, sine you had higher-than-normal pressure with your stock FPR. After installing the AFPR you should *technically* get the same result uptop once you build boost since both fpr's would then work at same pressures, whereas your old one would only flood during the lower rpm. Or maybe the winebro rose the pressure across the whole rpm-range, pretty hard to check without a fuel pressure gauge.

Raising it a few psi will not throw off your tuning so you can try that if its giving your problems. Although if the AFPRS is guarenteed to be working 100% then you simply will have to re-tune since your pressures changed.
Posted By: Jakub Kowalczyk

Re: AFPR tuning - April 23, 2005 05:50 pm UTC

I think the guage needs time to adjust itself.
This morning I turned up the pressure to 40 psi and after I drove around it went back down to 36 on the guage. I car did not start running lean, so it must be the guage.
I just came back from tuning, and checked the guage, and now it's at 35psi.
Posted By: Rob Strelecki

Re: AFPR tuning - April 23, 2005 07:51 pm UTC

Is it a liquid filled gauge?

I've recently learned that liquid filled gauges use glycerine, which heats up with your engine bay, and since the heat is not vented out of the guage it will read LOWER THAN ACTUAL, by up to 6psi.

Always set and check pressure when the car is cold.

Just look at the gauge while the car is off and not run for a while, the needle should rest on 0 (not on the peg below the 0 marking).
Otherwise, you will have a false reading.

I was about to beat my AFPR with a hammer, and then I was made aware of the above.
Posted By: Jakub Kowalczyk

Re: AFPR tuning - April 23, 2005 08:28 pm UTC

It is a liquid filled one.
That explains the flactuations.
I'll check the pressure again tonight, when the car is cold.
Posted By: Tim Grechin

Re: AFPR tuning - April 24, 2005 12:48 am UTC

Quote
Originally posted by Rob Strelecki:
I've recently learned that liquid filled gauges use glycerine
Don't let the days go by. It could have been easier on you... hahah

Yeah, I suppose and actually recommend you buy yourself an in cockpit ELECTRIC fuel pressure gauge. It's KEY. I run the Stewert Warner gauge; it's only $115 new taxes in to your door. Watch the pressure raise inline with the boost You'll know if theres a malfunction in the fuel system BEFORE it causes damage to the motor.

It helped me NOT blow my motor twice.

First time when one of the external lines on the FWD was cut or knicked from outside debree I suppose. The pressure was erractic as the power to the pump was weak.

Second was when my turbo fuel pressure regulator failed. Above 10psi of boost, my fuel pressure just dropped like a brick in the ocean.
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