I went down to function tuned on friday to have Dave retune my car with the new 2.87 pulley that I had installed earlier this week. A quick run through of my cars mods are as follows: Vortech tuner kit, 650cc injectors, walbro pump, test pipes, injen ses exhaust, mrev 2, 5/16" spacer, and the 3.9 final drive. I am also a 6mt. Right now I do not have a fuel return setup on my car. When Dave was tuning it origionally we ran out of fuel at 6100rpms! The 650's were at almost 100% duty cycle. BTW I have a revup motor. So after playing around with the fuel pump and removing the drilled oem pressure regulator and turbonetics modified fuel pump assembly Dave was able to get the injectors to support fuel to 6,500rpms. He then had to further play with the scaling of the injectors and timing to be able to support my 7,000rpm redline and have enough fuel to get there. My final power numbers were for that day were 364whp and 310wtq @11psi on Dave's dyno dynamics dyno. I know that I need to get the fuel return to run the injectors better and safer and I am getting on in the next month or so. My main question is, how much more power do you guys think I'll be able to squeeze outta my car once I get the fuel return? Id like to make if possible around 390-400whp on a dyno dynamics dyno like Daves. Think this is possible with my setup once the fuel return is on or should I also look towards other mods suchs as a 28th supercharger cog pulley, or maybe headers?

 

I would just go with dave,s own fuel return that is what im doing very soon to run 9psi.I dont think youll make any more power but it will stabilize the fuel pressure and let you make more power safely.

 

we have probably 20-30 cars with those same injectors with over that hp number. there is no way that they are at 100% cuty cycle UNLESS you did something or there is something wrong with the fuel pump/bucket setup.




you should be able to easily see 400-440 on that setup with a walbro and stock fuel system.

 

I didnt have anything done to it Jermey. I had the turbonetics modified setup like you told me to do when I first installed it, but then Dave replaced the drilled assembly and regulator with an oem one to help with pressure to make more power up top and that supposibly worked to a certain degree. But again Im talkin about making 400whp on a dyno dynamics dyno, not a dyno jet. If possible, what should I check to see if there is anything wrong with the setup?

 

bump?

 

On my setup I made 420hp on just rc 440c, fuel return line, and 2 fuel pumps on DD. I'm not sure what's wrong with your setup bc 550cc is plenty to get at least 400hp on a DD without stressing. U have 650cc so there should be no way u are running out of fuel up top unless u have some faulty injectors, bad pump or too big of a hole drilled into the fuel pump assembly. If u decide to get the fuel return line it still might not fix your problem unless u figure what the real reason for the lack of fuel up top.

 

I had the correct holes drilled in the fuel pump assembly, but we then took it out and replaced the assembly with an oem non drilled one. I thought that I would be fine getting to 400whp on a DD but either I was wrong or something on the car could be malfunctioning. How can I check my pump and injectors to see if they are working properly?

 

replace them

 

Ha, fun. Nothing easier?

 

Sounds like you using the OEM fuel pump? If so this is a problem...

 

No I have a Walbro 255lph pump! Anyone else?!

 

Drilling out your FPR and yellow swirl nozzle helps keep your fuel pressure closer to stock at idle and allows more flow. I think this necessary with the Walbro pump. Even with the return system, you still need to drill out the swirl nozzle to lower your fuel pressure at idle.

 

care to explain a bit more please?

 

I just posted this in another thread..

I have the Walbro and did not drill out the FPR. As a result my fuel press is around 80 psi normal non-boost conditions..Under boost the Vortech FMU/Aux fuel kicks in and press goes up and up and up..I also have 440 inj's. I have not experienced any problems with fuel delivery but 80 psi with the Vortech fuel lines up to the FMU scares me..The drilling mod brings the fuel press down to around 50 psi I believe..

 

I also have the same issue running out of fuel up top.

 

^^+1

 

check out the CJM website and look up the installation instructions. To the OP, if you don't have a RFS you need to drill out the regulator and the yellow swirl nozzle. The 650 injectors should not be at 100% duty cycle with that pulley.

 

+1..i know jeremy is right..cause im one of those cars..lol

 

I had the pump drilled and the swirl nozzel drilled and thats when it was running out of fuel at 6,000rpms. When switching back to the none drilled pump and nozzle I got more fuel up top but just barely so we had to scale the injectors. Im gonna contact jermey and ask him about this.

 

Another vortech car on Dave's DD dyno put down 390whp and the only thing it had done over me was the fuel return. Am I actually loosing out on almost 30whp because I dont have the fuel return?