2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

20b fuel pump

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Old Sep 21, 2001 | 07:32 AM
  #1  
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20b fuel pump

hey.. i have a 1990 turbo rx7. i have intake,fcd, and full turbo back rb exhaust. if i put in a 20b fuel pump and rewire it, do i need a afc to tune it down?

thanks.
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Old Sep 21, 2001 | 06:56 PM
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anybody?

my situation is i got my new engine, i got the turbo rebuilt, and i dont want another blown engine. is a 20b fuel pump rewired be enough? or do i need 720cc secondaries and a afc also? i gotta make decesion by tomorrw while the engine is out still...

thanks..
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Old Sep 21, 2001 | 07:17 PM
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Get a Walbro 340 factory replacent intank fuel pump. It supports up to 600 flywheel horsepower when hot wired (larger 14 guage wire run to the fuel pump from relay. It is rated at 255lph and as the Fuel pressure rises with boost it doesn't drop off on flow like other pumps, and will be more than enough to supply your setup. You can never have to large of a fuel pump especially with a turbo rotary engine.

They are $109 brand new and I run one and have no complaints. Took 30 minutes to install taking my time. Instructions are easy to follow. 11.60's@114mph with this pump on my car.

If you need a contact where to get one I can provide you with that info.

GNX7

email me at gnx7@hotmail.com if you want the info.
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Old Sep 21, 2001 | 07:38 PM
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hey man.. thanks for the info.. so i dont need injectors and a afc with my mods?

thanks..
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Old Sep 22, 2001 | 10:27 AM
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From: Marietta, GA
couple questions

The walbro should give you enough pressure/volume for your setup, assuming your running less than 10psi. Do you have a boost gauge? If not, buy that next. If you're going over 10psi, things get tricky. Basically, with the FCD, you're telling the ECU you're ALWAYS topping out at ~8 psi, so it never increases the injector duty cycle past that. Additionally, there is some dispute among those that have reverse-engineered the factory ECU as to whether it even has maps for > 10psi. Some additional pressure/volume from the pump helps offset this, and can produce some significan flamage on decell

FWIW, a friend is running 720's (secondaries)/ Walbro/ K&N/ dp, and an SAFC on an otherwise stock '89 car. IIRC, he put down 207rwhp on the dynojet (4th gear).

One other note, if you get greedy with the boost, the fpr will increase the pressure (like it's supposed to), however, at 14psi boost for example, the walbro is trying to push max volume at 55psi (40psi + 1psi for each pound of boost). At 55psi, the walbro's volume is dropping - means fuel pressure will start to drop. So, pay attention to your boost.

All best,
Steve C.
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Old Sep 22, 2001 | 05:13 PM
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thanks.. i wont go past 10 lbs..

appreciate the info... i'll save the injectors and afc for next year.
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