I paid over $1,000 to gain 23hp...Sound right to you?

[2001BlownGT]

I got my car dynoed today. Actually I had it first dynoed a few weeks ago only to learn that I pegged the MAF and that the stock fuel pump was loosing pressure at 5,000 rpm. Here is what I had before:

-01 GT 40k miles
-Ps1c Procharger 8lbs
-2 core intercooler
-42 lbs injectors
-Stock manifolds
-Offroad Xpipe
-80mm Mass Air ------------------Made 366 hp and 352 ft/lbs
-Accufab 75mm TB
-Accufab Plenem
-Diablo Revolution Chip
-3.73 gears

Here is what I have now:

-01 GT 40k miles
-Ps1c Procharger 8lbs---added AFM power pipe
-2 core intercooler
-42 lbs injectors
-Stock manifolds...
-Offroad Xpipe
-80mm Mass Air-----added a MAFia
-Accufab 75mm TB
-Accufab Plenem
-Diablo Revolution Chip--------changed to SCT Xcal2
-3.73 gears
ADDED: focus fuel pump
Got a dyno tune..

Now the car made 391 hp and 398 ft/lbs I spent over $1,000 to gain 23 hp..Should I be getting more hp? My goal was 420hp.

My tuner says that the car is loosing voltage at 5,000 rpm and that its only has 12.3 volts after 5k rpm.. This common? He stated that I should change the alternator...You think hes right or is it common? Thanks in advance..I have a 10 lb pulley for it but he wouldnt put it on untill I fixed the voltage problem...Any other suggestions? you think Ill get 420 hp with 10lbs?

 

[DropTopPony]

you gained 23 hp without adding any power mods so what are you complaining about? maybe you should have went with a 90mm SCT MAF instead of the MAF extender thing.

 

[deftsound]

you gained 23 hp without adding any power mods so what are you complaining about? maybe you should have went with a 90mm SCT MAF instead of the MAF extender thing.

he put a powerpipe on...

 

[Stan Weiss]

>> its only has 12.3 volts after 5k rpm <<
I do not know if this is common, but the system should have higher voltage. Was the fuel pump lossing presuure at 5000 RPM becuase of the low voltage?

 

[Mossberg]

I would look at how much torque you gained instead of concentrating on the hp! That newfound torque should make you happy by itself with a centri blower.

 

[COramprat]

What were the gains throughout the band? Peak my seem low but you may have done better throughout the entire range.

 

[chuck943]

I suspect with the voltage dropping to 12.3 after 5k rpm that this is really effecting VREF voltage giving the tuner a hard time getting the timing and fuel curves he wants.

 

[Kilgore Trout]

Maybe you need KB BAP and BAS?

 

[tomustang]

I paid over $1,000 to gain 23hp...Sound right to you?

Wrong, you spent 1 grand so you don't blow your motor with FI, just cause you spent money on a dyno tune and supporting mods doesn't mean you wasted money, you could spend up to $900 on a dyno tune and gain nothing but the satisfaction that your car won't blow up

 

[04YELLOWGT]

Very true, I just spent close to $1000 on a Cobra Tank and Pumps. I didn't gain 1hp with that but I now have the fuel system to keep from maxing out my fuel pump and leaning my car out.

Also keep an eye on that MAFia I had nothing but problems with mine. My my car ran like sh**t down low, actually every where. So bad that I went from running a 12.2 to running a 11.64 by just changing that out. LOL The funny part was I lost power too when I removed it due to some tuning tweaks and still ran faster.

 

[the98stang]

Do you have a dyno sheet? I'm curious to see the AFR.....

 

[COramprat]

Wrong, you spent 1 grand so you don't blow your motor with FI, just cause you spent money on a dyno tune and supporting mods doesn't mean you wasted money, you could spend up to $900 on a dyno tune and gain nothing but the satisfaction that your car won't blow up

That too...I had mine tuned and although I gained very little in peak (the tuner actually apologized) I knew that it cleaned up the entire range. I picked up 4 tenths and 5 MPH at the track so I know it did some good.

 

[2001BlownGT]

Thanks alot for everyones answers. You guys are right...atleast I know Im safer now..The car actually did clean up real well through the entire range. It feels much smoother now..Ill post the dyno sheet up tomorrow. The A/F stayed around 11.3-11.5 untill it reaches about 5400 rpm and then it went to 12.2-12.3..Im putting an alternator on tomorrow and I'll see. At night when I hot about 5600 rpm on the street I can see my lights dim. He swear I should pick up like 10 more hp b/c of the coils not getting enough voltage...This true?...Thanks again!!

 

[the98stang]

Thanks alot for everyones answers. You guys are right...atleast I know Im safer now..The car actually did clean up real well through the entire range. It feels much smoother now..Ill post the dyno sheet up tomorrow. The A/F stayed around 11.3-11.5 untill it reaches about 5400 rpm and then it went to 12.2-12.3..Im putting an alternator on tomorrow and I'll see. At night when I hot about 5600 rpm on the street I can see my lights dim. He swear I should pick up like 10 more hp b/c of the coils not getting enough voltage...This true?...Thanks again!!

Sounds like you need a little more tuning if your hitting above 12:1 AFR. It's not good for the engine to be lean, especially at higher RPM ranges. 12.2-12.3 isn't super dangerous, but you could use a little more tuning.

I think it would be a good idea to get a new alternator if your tuner says the voltage is low.

 

[Mike97gt]

your voltage should be higher than that. Either the alternator is toast or the belt is slipping past 5k RPM's..

I would check the belt and tensioner first then go for the alternator. When the tensioner goes many times you will have belt slippage at high rpm's

 

[chuck943]

Here is an article on Boost-A-Pump, it will help explain what the voltage drop you are experiencing does to the fuel system.
http://www.kennebell.net/media/articles/Boost_That_Pump.pdf