According to my data logger, my car is running lean at medium throttle and above.
It is a 350 but still has the 19 # injectors from when I had a 305.
I would like to install an AFPR, but something in the back of my mind says this will only affect wide open throttle fuel pressure.
Can anyone verify this?

Cheers

Richard

 

If you are not compensating for your smaller injectors by raising the fuel pressure, then yes, you are for sure running lean at WOT, and possibly at part throttle. The computer only can adjust so far with the stock programming, and you may be at it's limits of adjustment.

305 to 350 swaps (done correctly) need at least 3 things:

- change knock sensor to 350 one
- change the chip
- change the injectors (or raise the fuel pressure accordingly)

If you dont do these things, the car will never run to it's potential.

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Mike Metzler (Desert86Roc)[*] Check Out:SpeedWorldMotorplex.com[*] Check Out:Chevrolet F-Body Online Part & Illustration Manual[*] www.MetzlerRacing.com

Best ET @ 1250 ft[*] 15.352 @ 91.215 mph (uncorrected)

 

Thanks Mike for the reply, I purchased an AFPR and guage, and will check the normal pressure, then install, and adjust as necessary.

Thanks again

Richard

88 GTA, 350 TPI, ported plenum, small other stuff.

 

I think you will be happy. Raising the fuel pressure IMO is needed with the smaller inj. on a 350. I don't believe the computer can adjust fuel pressure, it's adusted by the vaccum line attached to it according to engine load, but you can manually raise the pressure with an AFPR. It will give you more potential for fuel at all throttle positions and should definately make it richer at WOT.

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14.62@96mph headers, muffler, chip, ghetto stuff, duct tape
89 GTA 305 TPI 5 speed 3.42 gears