The reason I want to know If anyone has a gt35 size turbo running 850cc x4 injectors is because when I intially had my single turbo modification installed the shop that I took it to sold me the kit and did the install...the problem is when I bought the kit he told me that the 850cc injectors would be plenty to support my build.

First question. Does that setup seem feasible? Because after almost a year of working on my car...prepping it to get to 15 psi I run into a huge problem. So yesterday, I was finally dialing in my tune to get to 15 psi and then I hit a brick wall. My Fuel setup that they installed does not support the 15 psi. I am completely unable to get a/f's at a safe level because my injectors are maxed out...

Jacobs 1000 Igintion Box
Upgraded spark plug wires
NGK 9 series plugs
Denso 300 flow rate fuel pump
850 cc x 4 injectors
Precision Turbo GT -37 (Simular to the Garret GT-35)
Greddy Intercooler
3inch exhaust w/ no cat
HKS Bov, Exhaust Manifold, Muffler
And a few other supporting mods...

With that setup, does anyone see a problem running that much boost with that size turbo? Honestly, I am pissed that this shop sold me this kit that does not even support itself... Any advice before I call the shop? Do I even have a right to... Thanks in advance for the input on this

 

Definitely not enough fuel...

 

Does my denso pump supply enough?

 

have you rewired the pump? Do that first if you haven't. It will drop your injector duty cycles significantly... I have a Denso Supra pump and I noticed a big difference. It flowed enough fuel for 21psi on a T04S (a little bit smaller turbo than a GT35)

 

4 x 850's should be plenty of fuel. You can make 400 crank easy with those injectors. 15 psi on a 35r should be shy of 400whp. As stated make sure you rewire the fuel pump, but more importantly upgrade to either a 255 or supra pump. I made 406 whp on my r85 at 16lbs so there's no arguement that the 35r will break that...

 

I did a little number crunching and with 850's all around you have the capability to make 410whp at 80% duty cycle.

 

But in reality world, he's going to find out its not enough fuel injector and will be in the 90~99% duty cycle. The Denso is enough fuel pump wired correctly and you need a better FPR if your still stock. The GT35R can make 380~410 hp AT THE WHEELS at around 1 bar. And actually, the T04S (aka 60-1) out flows the GT35R slightly below 1 bar, so its not slightly smaller then the GT35R, but slightly bigger in flow (GT35R is more efficient above 1 bar). BTW, the PT GT37 from what specs I've read, is bigger then the GT35, GT35R.

~Mike..............

 

850cc and 1200cc would be enough for 15psi.

btw I have those 1200cc forsale

 

If you use the fd fuel system calculator it shows 80% duty cycle (some tuners don't like going over 80%) and 410whp. I've used 4 x 850's in a customers car and he's 350ish whp at about 70% duty cycle (via commander). If your tuner says that your injectors are maxed out somethings up and maybe it's time for a "reputable tuner" or a professional second opinion (not my opinion).

 

Not enough fuel. If it were me, I would send 2 injectors out to RC engineering and have them bored out to 1300cc and use those as the secondaries.

 

the physical dimensions of the compressor wheel are smaller, that was my point, but you are right that the GT35 is a lower trim and is more efficient at higher boost.

 

Could my stock FPR be keeping me from flowing enough fuel. I thought that FPR's only regulated fuel being returned, not injected? Thanks for all the info before I sound like an idoit, venting to my builder... If my stock FPR is my bottleneck, which do you guys recommend for my setup...By the way I am tuning it myself, so that in itself might be the problem..

 

By the way, how would I rewire the fuel pump, if it isn't already.. Are there any good write-ups on it?

 

Go for an Aeromotive or SARD FPR then you can up the line pressure hence more fuel, 4x850 at 1 BAR with a good pump and FPR job done

 

Actually,

arghx and jon4825, you've mentioned the GT35, not the GT35R......... the 60-1 is bigger in flow and phsyical dimensions then the gt35, were the GT35 has an inducer diameter of 54.8mm and exducer of 76mm, the 60-1 has a larger inducer of 59.03mm and exducer of 76.2mm. It is a tad smaller then the GT35R, minor being 61.4mm and Major being 82mm. The 60-1 is still more efficient and flows more @ 1 bar then both GT35, GT35R. :P

Since we're being sticklers

And yes, theres a few write ups of pump re-wire, use the search function.

Upping the fuel pressure might get the job done, but keep in mind when your pressure goes up you put more strain on the injectors and fuel pump. Most start with a base fuel pressure of 40~43 PSI using a 1:1 rising rate regulator. Your best bet is to follow that with an after market reg (Aeromotive makes a quality unit), re-wire your pump and up-size your secondary injectors. Then you wont have to worry about your fueling needs running 1 bar or maybe even 18 psi (use higher octane or aux injection for more then 1 bar of boost is a safe bet).

~Mike............

 

There should be some good writeups on here for the rewire. There is several ways to do it. I have an external amp in the back so what i did is run a 4 guage wire from the battery all the way back to a distribution block which then splits it to two 8 guage wires. One goes to my amp and the other to the switched side of a 40 amp relay. I cut the original hot wire for the pump and used it to power the relay on. then ran the other switched side of the relay to the fuel pump side of the hot wire i cut. I also stripped the fp ground wire back and added a 10 guage ground to one of the studs close by sticking out of the floor. Don't forget the relay ground and to add fuses. I made sure i have a fuse at the battery and then a fuse off each side of my distribution block. My afr's were quite a bit richer after the rewire. And the voltage at the pump increased about 2 volts. You should get alot more out of your 4 850's by doing this. Whether its enough i dunno. If not then yes an aftermarket fpr will allow you to increase the fuel pressure and lower your duty cycles. Though your base pressure will be higher as well and might make it a little harder to lean the primaries out at idle. Were all your injectors professionally cleaned before you put them in? That also makes a difference. - Brent (reply by cell)

 

So my next step is going to be buying a FPR. There are the ones that I found. Any advice? Another question.... I have been reading alot about people choosing the aeromotive 6000-A, but insist that a bypass not a rising rate fuel pressure regulator? What is the difference? Will any liquid filled gauge work with these unit? Appreciate the help and responses for my application.

and by the way, that rewire seems a bit complicated from what Dude is saying... I guess I will have to read up on it..

http://www.rx7store.net/product_p/aeromotive%20fpr.htm

and

http://www.rhdjapan.com/jdm-low/SARD...te-Black-55194

and

http://twincamtech.stores.yahoo.net/sarfuelpresr.html

 

I have been reading about FPRs at

http://www.fd3s.net/fuel_pressure_regulator.html

and it seems a couple guys in here are running, multiple FPRs... running the stock regulator and a rising rate regulator. Am I just going to be replacing mine FPR? Should I use a Rising Rate Regulator or a Adjustable?

 

i would just go with a rising rate regulator 1:1. The rewire isnt that hard. it sounds more complicated then it is. it took me 20 mins. there are some other methods that are a little simpler. If you have a relocated battery its pretty easy too. For my method all you need is a relay a power wire and a short ground wire. You only end up cutting one wire that is right at the fp connector. If you under stand how a relay works u can see its very simple.

 

a picture is worth a thousand words. there are even some words in the pic to help. see its simple.

 

Is this regulator a rising rate or bypass.. or is the same thing?

http://www.rx7store.net/product_p/aeromotive%20fpr.htm

 

Thanks for the diagram. I am going to rewire my fuel pump when I get home.

 

Looking at the diagram. Does this setup take the voltage that usually goes into the fuel pump and replace it with a direct connection to the battery? If so what is the difference in voltage, since it now looks like it is going to get a straight 12 v from the battery?

 

thats a rising rate regulator.1:1 it will work good. looks identical to the one i have actually. you can also ditch the pulsation dampener with this regulator as the aeromotive are supposed to have it built in. also i think its better to take the stock regulator out entirely

 

its about 2 volts difference. you gain about half a volt from just the larger ground wire! it also bypasses the resistor circuit. all those connections with a relatively small gauge wire causes quite a drop in the voltage that the pump sees. normally the white/red wire is the +12v supply wire to the pump, but in this case it becomes the signal wire to turn the relay on.

other people do a rewire at the fuel pump relay under the hood. personally i prefer the direct approach. And as i mentioned earlier i have an amp that powers all my speakers so i ran an extra large wire and then split it, one for the amp and one for the pump. something to consider if you already have a sound system run.