I was just wondering if anybody knows the ( lph ) litres per hour of the stock fuel pump on an 88 rx7 turbo ii.

 

Anyone? Anyone? Where's that rocket when you need him?

I'd toss out a guess but my sig tells you how much experience I have with FC's or EFI!

Mario III

 

I'm on it, Mar. It's a complicated answer. This thread has pump flow data for NA & TII pumps at 12V & 13.5V.

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/measured-flow-stock-tii-pump-524944/#post9154530

If you compare the data to say a walbro 255 high flow pump:

Walbro 255: 213 lph(40psi) @ 12v
255 lph(40psi) @ 14v

Stock TII: 105 lph (40psi/2.8 bar) @ 12v
130 lph(40psi/2.8 bar) @ 13.5v

But 40psi isn't really the working pressure the pump will see under load. If you assume ~10psi loss from the pump to the fuel rails, the working pressure of the pump will be approx. 40 psi (idle) to 62 psi (@ 12 lbs. boost). For every 1 psi of manifold pressure change, the FPR increases fuel pressure by that same amount. The stock TII pump (13.5v) at about 62psi (4.3bar) flows only 86 LPH, but a walbro (13.5v) at the same pressure flows about 220 LPH. A stock FD fuel pump flows about 150 LPH at this same voltage and pressure. The crappy flow of the TII pump at this pressure is the biggest reason people blow their engines by turning up the boost alone. It flows ok at stock pressure, but takes a nose dive beyond that.

The one big draw back to a walbro is dramatically increased flow at low pressures, which will make idle very rich.

 

Dannnngggggg!!

Great stuff there! Thanks, RR!

 

Thanks for the fuel pump info.....I installed the walbro 255 lph high pressure pump yesterday hoping that it might help with my detonation problem. It did lessen the amount of occurrences but did not eliminate them. I had to retard the timing again to prevent the detonation. I wish I would have known that this would happen before I installed the racing beat exhaust. I emailed racing beat and they said the problem is most likely the pump, filter, or wiring. I replaced the pump and filter, I guess I'll have to check my voltage to the pump...

 

Pump voltage is critical, but you still don't know exactly how much boost you're making. You said the stock gauge maxes out, so you could actually be hitting 10-20 psi and not even know it. If you haven't done so yet, disconnect the FCD. You shouldn't be driving hard right now anyway, so keeping the car under 8.6psi (stock fuel cut) is not going to be a huge deal. Racingbeat's advertised ~50hp gain from the REV TII exhaust is mostly because of the boost creep it creates. They know about it, but they subscribe to the idea that an FCD will make it all better. It won't. Zero fuel (fuel cut) is much better than having too little fuel.

 

I only get the detonation in 4th and 5th but i never really get on the gas in 5th.. Anyway I dont do any freeway driving so i never really hit 4th gear(except for low rpm when cruisin around) so I'll just leave the fcd for now(hopefully I wont regret it) because I am saving for RTEK 1.7 and injectors. Also, off topic but... Im not really a handyman and was wondering if anyone know of a shop near Lake Elsinore Ca that ports wastegates and how much it cost. I have heard of Lucky 7 Racing but thats it.