TROLL's Supra: RPS Carbon Twin Disc clutch installed, retuning fuel now

[TROLL]

Originally Posted by mikes93

Looking good Bryan, keep up the good work and can't wait to see it. I hope you don't do so much that you would not want to drive it and just going to the shows with it.

I'll drive it I promise! Can't wait to... this whole build process is cool, but I'd rather just be behind the steering wheel already. Getting exhausted but I'm pushing through, the end is near. I'll make the effort to keep her in nice condition but the car will be driven properly, so don't worry... it'd be a waste not to.

Originally Posted by Vince@R/TTuning

Hey Bryan they have swivel hose ends that go directly to NPT that give alot more clearance then the AN fittings to an hose ends....here is what i mean:

And Vince, thanks for linking that... someone else had suggested that on SF and it was the next thing I was going to look into, but the only concern is that I cant come straight down out of the turbo or I'll hit the manifold, the line has to go to the left some before turning back toward the motor to clear the first runner on the manifold. Maybe the line itself will be able to bend around it if I make it the right length to loop a bit, I'll have to see.

If that wont work do you have any other ideas on something that will work? I was thinking a custom hard line to at least get me past the manifold and compressor housing, and weld an AN fitting on the end to do the second half of the line in braided hose.

[lagos]

Originally Posted by WKderF

the things i was wiring are relays for the fuel pumps. 2 of the relays are for fuel pumps, and there will actually be 2 extra relays pre-wired for anything that might be added or changed down the road that will require power.

Does the OEM fuel pump use a resistor pack to kick down the voltage to the fuel pumps at idle?

[TROLL]

Yes there is a fuel pump ECU to switch between 9v and 12v, but this portion of the ECU's function is bypassed with the relays. Other functions like pump priming when the key is turned and shutting off in an accident are retained.
There are a lot of different ways to set up the dual pumps, but for now I will have both running in unison. The other option would be to wire in the second pump to activate at a certain threshold like 50% throttle or 10psi or something, triggered by the engine management. I may do this in the future but I haven't heard a strong argument for or against at this point.

[lagos]

Good to know. Im using an oem supra pump on my car. They are very quiet compared to the annoying walbros and well worth the extra money.
However I noticed that with the pump running at full blast, the heater on, headlights, etc... I get too much of a dip in voltage at idle. Ive been thinking of wiring my resistor pack back in to help reduce the voltage draw from the pump at idle.

I don't know how other guys do it with dual pumps, but I would think two if them running at all times would put a bit of a drain on your electrical system at times when the extra pump is really not needed.

[Erik]

Im not familiar with supra's, nor running a duel fuel pump system, but what would the gas milage be with this setup? Im assuming its gonna be pretty low. Im sure if you wired the second pump through the management system to kick in at 50% throttle like you said, it would help with the milage right?

[lagos]

Originally Posted by Erik

Im not familiar with supra's, nor running a duel fuel pump system, but what would the gas milage be with this setup? Im assuming its gonna be pretty low. Im sure if you wired the second pump through the management system to kick in at 50% throttle like you said, it would help with the milage right?

No the extra fuel is controlled by the fuel pressure regulator. So most of it will just cycle back into the fuel tank. It really wont affect gas millage.

[TROLL]

Yeah the Supra Denso pumps do draw a lot of power but I was told it shouldn't be an issue unless I have a bunch of accessories and a system I want to run at the same time.

And Erik... the way a fuel system works is the pumps push the fuel to the front of the car, but the engine/injectors only use some of it, and the rest just circles back in the fuel return line and goes back into the tank. So mileage wont be affected at all, it'll just be cycling more fuel... the one drawback there is it raises the temperature of the fuel, and also the pumps wont last as long if they're running full time.

[russiankid]

Originally Posted by Erik

Im not familiar with supra's, nor running a duel fuel pump system, but what would the gas milage be with this setup? Im assuming its gonna be pretty low. Im sure if you wired the second pump through the management system to kick in at 50% throttle like you said, it would help with the milage right?

All fuel injected engines have a return line. Number of fuel pumps doesn't matter because the engine can only take in so much, the rest just circulates back.

[Erik]

ahh ok guys. i never really understood the fuel system entirely. I always wondered what the other hose was lol. my fault for not looking into that myself before asking the question. Thanks for the info

[TurboTagTeam]

Originally Posted by russiankid

All fuel injected engines have a return line. Number of fuel pumps doesn't matter because the engine can only take in so much, the rest just circulates back.

No they dont. Some car's systems use returnless fuel systems. The FPR is located on the fuel pump in the tank.

[russiankid]

Originally Posted by TurboTagTeam

No they dont. Some car's systems use returnless fuel systems. The FPR is located on the fuel pump in the tank.

Didn't know that. What cars have that?

[Vince@R/TTuning]

Originally Posted by russiankid

All fuel injected engines have a return line. Number of fuel pumps doesn't matter because the engine can only take in so much, the rest just circulates back.

Not entirly true...most newer cars are returnless and the more fuel u have pumping at idle just starts to heat the fuel and the hotter the fuel gets, the easier it is to cavitate...

Bryan will be OK with his set up but when you start to run dual pumps on race car set ups u typically only want one pump running at idle...

[11secdsm]

Originally Posted by russiankid

Didn't know that. What cars have that?

SRT-4, GS300, etc.

The car looks to be coming along nice Bryan. All the hard work will be well worth it in the end.

[Kevin]

Did you go with two pumps to cut down of fuel pump whine? After driving blkz06's car his football sized single fuel pump was loud as all hell at idle.

[lagos]

Originally Posted by Kevin

Did you go with two pumps to cut down of fuel pump whine? After driving blkz06's car his football sized single fuel pump was loud as all hell at idle.

He must have a Whinebro pump. The OEM supra pump is actually really quiet and flows just as much fuel as a walbro.
The reason for two pumps is usually when people feel like they will make more power then one pump can supply.

[TROLL]

thanks chris... gotta see if i can hang with that evo once i have things sorted out

and i bet blkz06 has an aeromotive pump or something external... he's supporting more hp than i am and those pumps are loud.

the walbros are pretty loud for in tank pumps but dont compare to the aeromotive external pumps.

the supra densos i'm running are quiet comparatively, and the reason i'm running 2 is because a single pump is said to only support about 500 whp comfortably, so running 2 ensures that i'll be able to sustain my fuel pressure without any worries.

edit: wait a tick kevin... please tell me that you arent confusing a fuel pump whine with a supercharger whine... hahah. i'm assuming you're not, but i'm surprised you could hear the pump over that insanely loud blower...

[Got Insulin?]

I actually run a Supra TT pump in my DSM because:
1. They are pretty easy to come by,
2. Can be had for less than a walboro of similar specs
and 3. since they are OEM, the noise is pretty low-key, which I will attest to. Plus, it's cool saying that I have Supra parts in my car. haha

[mikes93]

My wallbros are loud and the older they get the loader they became. Also when you get to 1/4 tank of gas it gets even loader. I will go back to toyota ones when its time to replace them.

[Mitsu3kgt]

The thing that makes walboros better then the denso supra pumps is that at higher pressure levels the more constant and more volume they flow. If you have the cover over the walboros they sound just like densos. I'm running twin hotwired walboros in my 3000gt and the noise doesn't bother me and isn't really that noticeable with the covers on them and the sound of my exhaust. I'm actually about to install a aeromotive a1000 inline pump to assist the twin walboros since I'm planning on running E85 this spring.

[Vr-4-Life]

my vr4 has a single 255 and its not that annoying. However my del sol has a single 255 as well. and since the pumps practicly right under the seat its very annoying at times.