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Author Topic: New Member with questions about Rocketchip and other fueling methods  (Read 402 times)

Aus Capri

  • Newbie
  • *
  • Posts: 4
    • 1989 Capri Turbo

Hi all firstly great website, what an awesome resource to have at our fingertips!
My question is are rocketchips still available? I am very keen to acquire one for my Australian RHD 1989 Capri turbo 1.6B6T,
I see rocketman is still here so i hope.

I have a wideband 02 sensor installed into the exhaust and i have been playing around with the boost. I have the boost turned up to 16psi and to try get the air fuel ratios to stay low i completely clamp off the return fuel line to increase fuel pressure to the injectors. With 16psi and return line clamped the AFR's climb from about 11-1 to 13-1 in first and second gears and around 11-1 to 15-1 in 3rd and 4th gears. Does any one know if this is harmful to the motor or fuel regulator or ecu? after driving the car with 16psi and clamped fuel return for a while then going back to 7psi and open fuel return the afr's go high 16.1 at idle and 14-15 on boost, long term fuel trim trying to compensate maybe?

any way i want to stop doing this its a pain in the ass because every time i stop the car i have to unclamp it. (don't leave it clamped as the fuel in the rail heats up when the car is stopped and expandes and pops the fuel line off)

Im getting a vj11 next week and i would like to do it properly so rocketman if your out there please help!


  • Administrator
  • Old-Timer
  • *****
  • Posts: 5122
    • 91 BPT AWD Capri & 1991 XR2

Yes, I'm here, and still making Rocketchips. Please shoot me an email thru my website:

Yes, clamping the return is a very bad idea. You're sending way too much pressure thru the injectors and may harm the FPR. Risking popping the fuel line off is asking for a burned up car, too.
An 'old school' way of achieving what you're doing is with an "FMU": "fuel management unit" (a bit of a misnomer) which is a Rising Rate Fuel Pressure Regulator. They raise the fuel pressure X number of PSI for every pound of boost you add. (you can get them with different rates) This was a marginal solution for originally nonturbo cars running low boost pressure without getting into ECU work.

You don't want to go above 12:1 when you're under boost. Your numbers are showing dangerous conditions inside the engine. Lean conditions under load make the combustion chamber run hot, and can melt the pistons. (I have done this in the past, it was not fun) I can't explain the super lean numbers after you unclamp it, I am unaware of any temporary fuel trim in the ECU (that is more of a modern ECU thing) It's possible that your fuel pressure regulator is damaged. If you remove the vacuum line, does fuel come out?

Send me an email and we can discuss some Rocketchip options :)
1.8L Turbo All Wheel Drive Capri... the "GTXR2"