Supra fule pump on an FJ100

[cdeel]

Supra fuel pump on an FJ100

I haven't seen this mentioned yet (it is always the 80s with the supra pump) but have any supercharged 100s upgraded the fuel pump? I seem to suffer the same fuel starvation in the upper RPM bands as the 80s, and need to get more fuel in. Any thoughts or suggestions would be appreciated. Or at least pointers (no, not that one ) in the right direction

 

[DMX84]

Will the stock fuel pressure regulator handle the added fuel pressure? You may need to put an aftermarket AFPR. On my VR4 the stock FPR won’t flow enough gas to keep it at the proper setting, causing it to build up to much pressure at idle/low speeds (causing a rich condition).
The AFPR allowed me to get the pressure back to down to the proper level and w/ the larger pump gives me the added flow rate I needed at the upper RPM’s. (I’m running 660’s)
Are you measuring the fuel pressure? How low is the pressure getting?
I think if you see a lean condition at the upper RPM’s then a bigger fuel pump certainly wouldn’t hurt.
FWIW, I thought the 80 guys were adding an extra fuel injector on the manifold?

DMX

 

[cdeel]

Good points, although the 100 already has a 9th injector. I don't yet have a way to measure the fuel pressure, it is only based on descriptions from the 80 series guys, but it sounds the same. It seems the truck pulls to strong at part throttle and too weak (all sound no go) at full throttle. However, there is not a lot of chatter on the 100 series superchargers....

 

[clownmidget]

Chris, as a starting point you can get a simple mechanical style fuel pressure gauge (like a Snap-On ...borrow one) and hook it up directly after your stock FPR in the return line that goes back to the tank. You can then crimp shut the vent line and observe how high your fuel pressure goes. It's not a comprehensive test but it'll at least let you know what the approx max output from your pump is. You can also test it more conclusively by bypassing the voltage regulator so the pump is running "wide open" on full voltage and again measure the fuel pressure and see if it is even able to keep it up around 50 psi. I highly doubt the stock pump goes above 45 psi at full tilt and you are probably running into a lean condition at high boost/WOT. Do you have an EGT gauge hooked up? You'll notice it there too (the lean condition) as your EGT's will take off (>1400-deg F). All in all, there's really no substitute for having a good boost gauge, EGT gauge and fuel pressure gauge as you tune this. Once you can observe what's going on you can more accurately correct it. Throwing in a Supra TT pump and a rising rate FPR certainly will get you more fuel but the gauges will save you a bunch of time and instill more confidence in your tuning. Good luck.

 

[sleeoffroad]

I woul suggest you get a wideband o2 gauge and check what you are running in terms of mixture. You might just be feeling the typical supercharger. Good off the line but runs out of oomph high up.

With the trubo systems we have 2 extra injectors and run a Walbro higher flow / pressure pump.

For a gauge see http://www.aempower.com/ViewCategory.aspx?CategoryID=66

 

[richg]

Is it the TRD kit? Do you know what boost levels you are currently running?

You really need to get some more data as to what is happening before putting any upgraded parts on the car.

A boost gauge (if you don't have one) and a wideband as slee suggested would be the best starting points. Having worked with many of the ones on the market, personally I prefer the NGK wideband http://www.ngksparkplugs.com//products/air-fuel/index.asp?nav=19000&country=US if you already have a means for datalogging (or don't care about datalogging at all). Its only about $200 and as far as accuracy, is the best out there. If you do want to datalog the signal, it does have a 0-5V analog output. There are other systems out there that sell a standalone datalogging package (with RPM pickup, etc) but they get a good deal more expensive.

rich

 

[cdeel]

it is the TRD system, yes. I have not logged any of the air/fuel mix data yet, I was simply basing this observation on the 80 series owners that are running larger fuel pumps and seeing better results. I was also trying to find any other 100 S/C owners out there (there don't seem to be many) to see what experiences they have had. I may look into the logger, but that is getting a little farther into it than I wanted. I already have another car I am spending way too much money on .

 

[richg]

Well, do you at all know what boost level you are running? Not what its "supposed" to run, but actually what its producing. There is some posts in the archives here about the TRD chargers running too much boost, and even with plenty of fuel, it could still be enough to blow an engine.

 

[DMX84]

it is the TRD system, yes. I have not logged any of the air/fuel mix data yet, I was simply basing this observation on the 80 series owners that are running larger fuel pumps and seeing better results. I was also trying to find any other 100 S/C owners out there (there don't seem to be many) to see what experiences they have had. I may look into the logger, but that is getting a little farther into it than I wanted. I already have another car I am spending way too much money on .

Chris, you could contact Dave (Toylexmod https://forum.ih8mud.com/member.php?u=5142 )
He’s pretty knowledgeable with this stuff, and has done lots of tuning. IIRC he’s on another Toyota site more then this one. I have his number if all else fails.
DMX