LT's and ORY installed = 0 gain in hp?

**GottaHaveLS1** · 09-04-2007, 11:48 AM

I now have full exhaust on my TA. It has ceramic coated pacesetter Lt's, ory and magnaflow catback. At first the car was running terrible, so i got it tuned but the guy said he couldn't tune the car to maximum power because it wasn't getting enough fuel. So I replaced the fuel filter (and put in MSD wires too) and i'll probably get the additive put in my fuel to clean out injectors. Is there anything else that could be holding back fuel? I was going to bring the car back to get retuned but i'm at school now and I have a Passat as my DD.

The car ran pretty good after the tune, but there wasn't a noticeable difference in power. She sounds nasty but I only feel a very slight "seat of the pants" difference. I felt better gains after installing the magnaflow CB over stock exhaust. I don't really care for numbers (as you can see cuz i didn't get it dynoed) but I'd like the car to feel faster after spending $1400 on parts, install and tune. A full dyno tune would probably help but can you guys think of anything else?

**BlueBomber** · 09-04-2007, 12:03 PM

Bad fuel pump? just my .02

**GottaHaveLS1** · 09-04-2007, 12:22 PM

Originally Posted by BlueBomber

Bad fuel pump? just my .02

How much would a new fuel pump cost? Is it difficult to find and swap? thanks

**keliente** · 09-04-2007, 01:19 PM

Hmm I think I would go see another tuner. Unless there is something mechanically wrong with the car (doubtful as you did not mention check engine light or driveability problem) the injectors/pump will be plenty for a bolt-on car.

You should see a pretty good gain with that stuff...around 20hp. Butt dyno should definitely notice!!!

**yellowv** · 09-04-2007, 03:33 PM

With a tune you should see around 30RWHP from headers, ORY amd exhaust. Sounds like your tuner doesn't know what hes doing.

**ATCharming** · 09-04-2007, 03:47 PM

get a new tuner

**GottaHaveLS1** · 09-04-2007, 05:24 PM

The tuner said that he couldn't tune my car to the max cuz it was not getting enough fuel. he showed me on his laptop where he told the computer that the car had 17 lb/hr injectors and it didn't help. I'd like to go to the same tuner, they had a lot of nasty cars at the shop and i would have to pay for the HPtuner software again....

**INMY01TA** · 09-04-2007, 07:12 PM

Like Keliente said the stock fuel system is more than adequate to do the job. What does your tuner suggest to get more fuel?

If he's tuned F bods before he should know (bs imo) You may not feel any gains but I bet a timeslip would show some. Did the dyno show any gains?

**GottaHaveLS1** · 09-04-2007, 08:21 PM

Originally Posted by INMY01TA

Like Keliente said the stock fuel system is more than adequate to do the job. What does your tuner suggest to get more fuel?

If he's tuned F bods before he should know (bs imo) You may not feel any gains but I bet a timeslip would show some. Did the dyno show any gains?

I am pretty confident in the tuner's ability. They had a Twin Turbo C5 pushing 750 rwhp, a fully built GTO and a supercharged 347 stang at their shop. A bad fuel pump wouldn't hold back fuel... the car probably wouldn't run well or at all for the matter (as far as i know). I didn't get the car fully dyno tuned, so i don't have any numbers. It was a street tune where he drove the car around with his laptop plugged in. He deleted codes, had the fan turn on at a lower temp, and messed around with timing and A/F ratio. He said he couldn't get it to full potential because of the lack of fuel going to the motor. What would happen if the fuel pump was messed up, cuz like i said the car is running pretty good.

**ATCharming** · 09-04-2007, 08:27 PM

a bad or insufficient fuel pump will hold fuel back. i know by experience. helped a friend build a 400hp supra and the only thing that really limited our power was the fuel pump. we had to tune it wayyyyyyy down like to under 300hp till he got a new fuel pump

**BlueBomber** · 09-04-2007, 09:28 PM

Those mods don't demand that much more fuel than what the pump is already used to. Unless your fuel pump actually took a dump on ya, I'd say your mechanic was hung over that day...

**GottaHaveLS1** · 09-05-2007, 05:44 AM

If my fuel pump took a dump, would the car still run fine? I would think the car wouldn't start or run well at all but I don't know much about fuel systems.

**35thAnniZ28** · 09-05-2007, 06:51 AM

Originally Posted by ATCharming

a bad or insufficient fuel pump will hold fuel back. i know by experience. helped a friend build a 400hp supra and the only thing that really limited our power was the fuel pump. we had to tune it wayyyyyyy down like to under 300hp till he got a new fuel pump

AHHHHHHHHH YOUR AVATAR!

**BlackLT1Z28** · 09-05-2007, 11:00 AM

Originally Posted by GottaHaveLS1

The tuner said that he couldn't tune my car to the max cuz it was not getting enough fuel. he showed me on his laptop where he told the computer that the car had 17 lb/hr injectors and it didn't help. I'd like to go to the same tuner, they had a lot of nasty cars at the shop and i would have to pay for the HPtuner software again....

What the hell is your car doing with 17lb injectors anyways? Definately not stock injectors...

**Spaz** · 09-05-2007, 11:09 AM

Originally Posted by BlackLT1Z28

What the hell is your car doing with 17lb injectors anyways? Definately not stock injectors...

+1...

plus the stock injectors are far more than capable of handling what ever hp number you will put out with exhaust... hell... mine are still good for my set up... but if i cam my car i will need bigger injectors..

**GottaHaveLS1** · 09-05-2007, 11:20 AM

Originally Posted by BlackLT1Z28

What the hell is your car doing with 17lb injectors anyways? Definately not stock injectors...

I said he tricked the computer into thinking it had 17lb injectors to see if it would deliver more fuel. But it didn't help. If my fuel pump was bad, how would the car run?

**firesilver** · 09-05-2007, 12:25 PM

I think your fuel pump is probley bad. I know my friend had a bad one in his lt1 and noticed alot of power loss but it was still drivable and everything.

buy a fuel pressure gauge and attach it to the schrader valve on the fuel rail and with the key in the on position without the car running it should be between 55 and 60psi.
some other things to check are the fuel pressure regulator and fuel return line.
this is all out of my chiltons manual.

**GottaHaveLS1** · 09-05-2007, 02:06 PM

Originally Posted by firesilver

I think your fuel pump is probley bad. I know my friend had a bad one in his lt1 and noticed alot of power loss but it was still drivable and everything.

buy a fuel pressure gauge and attach it to the schrader valve on the fuel rail and with the key in the on position without the car running it should be between 55 and 60psi.
some other things to check are the fuel pressure regulator and fuel return line.
this is all out of my chiltons manual.

I'll do that but I don't feel any power loss... except i would expect the LT's to add power. The car was also perfect before the LT install. The fuel pump would have had to go the same time the LT's were installed.

I'll check into all that other stuff tomorrow when I get home, thanks for the tips.

**ATCharming** · 09-05-2007, 04:40 PM

if ur fuel pump isnt workin 100% ur car would still run fine...
a little test, get it to about 1/8 of a tank left, take a corner hard, maybe goin downhill, while braking, and go wot out of the turn

see if ur car dies or acts like it

**GottaHaveLS1** · 09-05-2007, 04:48 PM

Originally Posted by ATCharming

if ur fuel pump isnt workin 100% ur car would still run fine...
a little test, get it to about 1/8 of a tank left, take a corner hard, maybe goin downhill, while braking, and go wot out of the turn

see if ur car dies or acts like it

Alright i guess i'll try that. One question: will my fuel pressure be messed up if the fuel pump is bad. I'll be testing it tomorrow.