problems, problems, problems...........

[fivemustangs]

I have my 2002 mustang gt at the dyno right now, I am asking everyones advice because the numbers he is telling me seems a little off. These are my mods, borla catback, short tubes, trickflow pleminum, aluminum drivehshaft,
4:33 gears, 42lb injectors, sct big air, p1sc procharger w/3core intercooler, greddy BOV and a kenne bell boost-a-pump and tuned with a diablo preditor. The first problem is he is saying that I am leaning out st 5000rpm with the stock fuel pump w/ the boost a pump, but when I talked to KB they said it was good for 500hp with the stock pump? and the second problem is he says the power right now at 5000rpm is around 290-305? Is he doing something wrong? are these numbers right? should my pump be maxing out? could I have hooked the BAP up wrong? I live in bar harbor maine and he is the only dyno tuner in the state that I know of, please send some insight for me. He has tuned the car before without the P1sc and it had pulleys but only pulled out 230 to the wheels. It is a mustang dyno and the car is a 5speed K code.

 

[fivemustangs]

Also the supercharger has a 10psi pullie on it.

 

[trinity_gt]

4:33 gears, 42lb injectors, sct big air, p1sc procharger w/3core intercooler, greddy BOV and a kenne bell boost-a-pump and tuned with a diablo preditor. The first problem is he is saying that I am leaning out st 5000rpm with the stock fuel pump w/ the boost a pump, but when I talked to KB they said it was good for 500hp with the stock pump?

I'm running a stock GT pump and BAP on mine at 9psi and am at ~400HP at the wheels (~450-460 at the crank.)

Are you certain the BAP is functioning? Is it hard-wired to run all the time or is it on a Hobbs switch (i.e. turns on at ~4psi)?

What is the fuel pressure doing during these pulls? This info is critical.

and the second problem is he says the power right now at 5000rpm is around 290-305? Is he doing something wrong? are these numbers right?

Seems low to me. What boost pressure are you seeing? Is the BOV leaking? Are all the couplings in the intake tight?

should my pump be maxing out?

No.

Is the fuel filter reasonably new?

 

[fivemustangs]

He says the car jolts or fluxuates when he hits around 5K and the fuel pressure drops, but he didnt tell me how low it goes. I dont think the filter has been replaced in a while, could that really make the pressure drop? How do i know if the BAP is working correctly? the car runs and idles and is good throught the driving part of the dyno, just not the full throttle. But I hooked it up the way it said, cut the black/pink wire and put in the 2 red wires and the ground, I dont have the boost switch hooked up the 2 wires are spliced together. Is there anything else needed ti be done? I know mustang dyno's have low numbers but these are crazy low, I dont think I am going to gain 100hp in 1000K. can I do a voltage test on the BAP?

 

[trinity_gt]

He says the car jolts or fluxuates when he hits around 5K and the fuel pressure drops, but he didnt tell me how low it goes.

It's important to know exactly what the fuel pressure is doing for the whole run. It could be something as simple as a vacuum line not hooked up correctly on the fuel rail pressure sensor.

BTW, I would refrain from boosting until you get this sorted out. Jolts and fluctuations may indicate very lean running and misfiring and could lead to engine damage.

I dont think the filter has been replaced in a while, could that really make the pressure drop?

To be honest, I doubt it. However, every ounce of fuel the engine sees passes through it and it is easy to replace. If it's older, just do it anyway.

How do i know if the BAP is working correctly? the car runs and idles and is good throught the driving part of the dyno, just not the full throttle. But I hooked it up the way it said, cut the black/pink wire and put in the 2 red wires and the ground, I dont have the boost switch hooked up the 2 wires are spliced together. Is there anything else needed ti be done? I know mustang dyno's have low numbers but these are crazy low, I dont think I am going to gain 100hp in 1000K. can I do a voltage test on the BAP?

It's tricky to measure the output voltage of the BAP due to the PWM (pulse width modulation) drive nature of the FPDM output. You'd only really see higher voltage reading on a DVM if you are able to measure the voltage under boost (and as I've said, be careful of this...) Eliminate other possibilities first.

 

[fivemustangs]

I am going to go up there today and see if i cant figure it out for myself. If i put a meter to the non fused end of the BAP will the readings jump around up to 17 volts at full rich? I really think it might be the BAp, fuel filter or maybe the vaccum line you just said. I hooked my BOV to a line that looked to go to the rear of the car, it came from the back of the pleminum i T'd it at the plastic devider.

 

[fivemustangs]

Ok so I went to the dyno today and took a better look at the fuel situation while we did some runs. The fuel was smooth, the pump was about 35-45% duty cycle which on a diablo tuner is about 80-90% he said. But when the engine hits 3400rpm every run (give or take a few rpms) the pump maxs out at 50% duty cycle and the car studders, the fuel pressure varies anywhere from 15-90 psi for a couple hundred rpms and then it smooths back out but the rail pressure is still a little lower then desired between 33-45 at wot. So we disconnected the BAP and connect the pump wires togeather and it still did the same thing but the pump was maxing out a lot quicker and the a\f was around 12 or 13 to 1 so anyone got any idea's?

 

[trinity_gt]

Any chance you've logged the MAF output for one of these runs?

 

[fivemustangs]

ya im sure he has, i can look tomorrow if it will help. its tuning with the diablo preditor so it logs all the engines functions. What am I looking for in the mass air data?

 

[fivemustangs]

Anyone ever have a problem like this? Im on the edge of ordering a bigger fuel pump to try and solve the problem.

 

[fivemustangs]

Ok well I am going to be installing a SVT focus pump tomorrow to try and give it some more volume. It seems like the pump just max's out for some reason at 3500 rpms and then its fine after that. I have tried it with the boost a pump and without it and its not as violent without the BAP, the preditor shows the pump is maxing out at that rpm everytime with and without the BAP. So I guess putting in a bigger pump should solve the problem, and the pump should not max out even without the BAP? I will stay posted but if anyone has any idea's? Maybe its something electrical or the fuel rail pressure sensor?

 

[fivemustangs]

Still waiting for this guy to install the pump. He recived it this past friday, he has WAY to many projects at his shop I really wish there was someone else around here that did dyno work.

 

[fivemustangs]

The new fuel pump fixed the problem, I swear kenne bell told me the stock pump was good to 500hp with the boost a pump. But now I got more room to play with!

 

[trinity_gt]

I'm running a stock GT pump and BAP on mine at 9psi and am at ~400HP at the wheels (~450-460 at the crank.)

The stock pump is good to that sort of power with a BAP. Yours may have been defective in some way.

So what are your new numbers?

BTW:

I got more room to play with

Depending on your bottom end, you may not have as much room as you think. I can make more power than is safe for my stock bottom end will take using the stock pump & BAP. Don't think that because your pump will flow 500HP worth of power that the rest of your setup (i.e. shortblock) is up to those sorts of power levels.

If your engine is built, that's a different story...

 

[fivemustangs]

I dont even want to post my numbers here......he pulled a whopping 311hp and 315tq to the wheels. Not sure how he managed to get thoughs numbers but I didnt question I just took the car and got out of there, he had my car for three weeks and thats all he came up with. My short block is stock and everything else is listed in my signature, after reading everyone elses mods and dyno numbers I figured i would be atleast close to 400whp. This guy is the only chassie dyno for 5 hours from here and he is still an hour out of the way.

 

[trinity_gt]

I dont even want to post my numbers here......he pulled a whopping 311hp and 315tq to the wheels.

You sure it's fixed?

Sounds like you need to find another tuner and/or there's still something wrong.

 

[fivemustangs]

Im not sure what he did, I can build them all day long but when it comes to the tuning part......The car is getting plenty of fuel now and it seems to be good the only complaints in the power for 1 but it also has a higher idle when i stop at a red light and it usually wont go back down from 1000rpm idle unless i turn the car off. Im fighting right now with my BOV I put a greddy type RS on it but I cant get the compressor surge to go away iv made it as soft as possible and hard as possible but it still seems to surge at part throttle and downshifting, I can hear it comming from the intake part of the procharger when I rev. it from the engine bay. I know people run the BOV's instead of the bypass but I cant figure it out. Any idea's? Trust me I am going to find a new tuner next spring, but I only have about a month left of driving before I pack her up for the winter. And the next closest chassie dyno is new hampshire.

 

[mudrun1]

I know you said you were at 300/300 on the dyno, but have you ran it? What does it feel like? Do you have a friend with a 400 hp car to test aginst? Also take it to the track. When mine ws dynod on a mustang mine made 380hp/450ft when I went to a dyno jet it made 440 and 500. Not sure if that is your problem or not. My tuner said that he loads the mustang dyno heavy and it yields better track times. I believe him, my car is quick on the street from a roll, but the numbers suck. This might not make you feel better but if you walk an ls1 then the dyno was wrong.

 

[fivemustangs]

Im not sure i'v never had a forced inducted mustang gt. My brother has a 331 stroker, aluminum heads with a weine roots blower on his 67 mustang and when his car goes......it goes. Mine goes good but its deff. different. I have 4:33 gears and I can get better traction in 1st and 2ed then I thought I would with this set up. I am going to take it to the track next weekend and see what it turns, But the track is only 1/8 mile.

 

[mudrun1]

the 1/8th still counts just focus on mph. Traction in first and second on street tires is not a good sign though. Best of luck too you.