Am posting this for a friend of mine. He was planning to reach about 400whp on his 94 RX7. He got himself a 13b with low miles and td06 turbo. He had the motor street ported and polished. Also, he put some apex seals. Computer was swapped to a T-12 computer. Extra injectors (secondry or whatever, i dont know much about rotaries anyway) were installed but not hooked to the fuel line. Thats pretty much all what is done to the car so far. Now, after swapping the other motor and installing everything, it was time for a dyno run. SURPRISE. 173rwhp @ 11psi. That was SO disappointing. I think that something is wrong with the fuel system. Specifically the fuelpump. As he steps on the gas, the fuel pressure drops to about 30psi.

Could the fuelpump be the reason why the car dynoed that low?

Are there any other things that might cause the car to run that poorly?

Any comments, inputs or suggistions on mods that would help reach 400rwhp are greatly appreciated.

Al

 

TDO6-20G OR 25G ?

Full GReddy turbo kit or pieces ? I'd check for fuel line blockage , change the fuel filter and pump and regulator . Make sure the FPR's vaccum source si good .

A street ported FD with a TD06 Should have no problem putting down 400RWHP with fuel and correct tunning ..

What computer is a T12 ? I'd get something more reliable like a Power FC or Microtech/Haltech .... Be sure to have someone knowledgeable tune it as well many rotaries blow do to poor tunning ...

 

Am not sure if its 20G or 25G, by its a full greddy kit. Sorry, i meant that the computer is an LT-12, which is made by microtech. Ive heard that the walbro 255 is decent pump and could support up to 400hp. Are there any other pumps to put into concideration?

 

A stock Supra TT pump would be better than a Walbro . I've heard of adn had some bad experiences with them .

They are are good solution if you need a pump ASAP thoiugh . Or else I would go Aeromotive or Supra TT ...

 

from what i've seen, the TT supra pump is pretty much the same as the rx7. i have a tII rx7 with microtech, upgraded turbo, etc. I am using one of the big bosch pumps, which is what i would recommend using, it pumps a lot more then the walbro, and it can still be mounted in the tank and everything. i had a problem with fuel pressure dropping at high rpm under boost. i put a relay back by the pump and ran a bigger guage wire right off the power lug on the starter to the relay so the pump now gets way more voltage. it picked up 10 psi of fuel pressure where it was dropping before, and the pump is audibly like twice as loud.

 

Yea , I deinfatelly think you guys are having a fuel problem .

Fuel starvation and boost in rotaries arent 2 things I would recomend combining either .

The large Bosch pumps would be an ideal solution . but an Aeromotive will also work .

 

yeah its def a fuel problem. But is it the only problem that is suppressing the horse power? i mean the dyno #s were almost half of what we expected to see. Ill be very surprised if it dyno 350+whp after changing the pump.

 

If your not getting enough fuel pressure then yes ... Your injectors therefore cant push enough fuel for you to safely go into the higher #'s..

Once you get the fuel pressure up the injectors will then be able to pulse at full length adn spray and give you better , faster , cleaner combustion ..

 

supra TT pump is 296lph, FD3S fuel pump is 190lph...

 

I HEARD that the RX7 turbo fuel pump runs on a voltage system, that increases power to the pump as boost increases, and I have seen these guys wire the pumps up directly and avoid this..