1/4 Mile Problems...Question?

[SAVANNAHAUTOAIR]

Hi, a friend of mine is having trouble with his GN...basic goal is to get it into the 12's. Below is the text he sent me, and my opinion, is that he needs to get the boost up a little above 20psi, and he'll be where he wants to be.

The main thing that bothers me is that he says it is shifting into OD...

Thanks, Brett

Here's what he sent me:

The list of mods are as follows:ta-49,009 injectors,rjc powerplate,adj. fuel reg,adj. wastegate,atr headers and 3 inch downpipe with dump,2 3/4 inch exhaust,fred brown trans and 2800 converter,turbo tweak chip,vdo guages.

There was some type of cold air kit on the car that located the air filter under the bumper but I took that off on Saturday and installed a cone filter behind the headlight.

I use a scanmaster 2.1.Some of the mods were on the car when i bought it(headers,adj reg and wastegate,trans and exhaust).My first pass with the car got me 13.70 @ 97 mph.Now the car goes 13.5 @ 98 mph.All runs were made on street tires so I wasnt able to build boost on the line.

Opening the dump didnt add or take anything away.I also installed a rjc boost controller because my boost wouldnt go above 15psi.Well it still goes to 15psi it just gets there faster.

Also because of the non lock up i have to let the car shift into 4th on the track.My scanmaster readings show no knock and O2s are 720-790.

I just want to be able to get the car in the high 12s in order to keep up with my friends.I dont want a bruiser because Ive already got one(88 Mustang LX with a blown 331 stroker).

 

[Red Regal T]

ALCOHOL INJECTION

 

[Louie L.]

Well ive seen plenty of stockers with TA 49s go 12s on street tires. Like you said he has to get the boost up. 20-24 will get it done. But it has the potential to go much faster if all else is there , like a good race chip with some timing, race gas and slicks or drack radials.Of course alky would work too.

 

[SAVANNAHAUTOAIR]

True, but he says it's shifting into 4th at the end of the 1320...kinda strange, don't you think?

 

[XLR8]

More boost - about 20# with good gas (100UL) or alky and some good tires - drag radials at least. And keep it in drive.

 

[SAVANNAHAUTOAIR]

I didn't think to mention to him to leave it in "D".....don't really think he has anything wrong with his car, just more boost!!

 

[Phatman]

Not that it's going to make any big difference, but I found that after running the ATR headers on a lightly modded car, I actually got better performance out of ported stock headers.

He's got them I'd keep them, and turn up the boost...

Fuel, chip, tires and gittyup.

 

[steve davis]

1/4 mile

i had almost the same set up last year on my t type i went 11.82 and their a lot of guys with the same setups running a tenth or two faster.nitto drag radals.25# of boost and leave it in drive 3

 

[scottyb]

Those mods are a waste at 15psi. He needs more octane or alcohol and boost!

 

[SAVANNAHAUTOAIR]

I wonder why he can't get the boost above 15psi?

Brett

 

[BLACK6PACK]

He may have the Y hose hooked up backwards on the turbo.

 

[SAVANNAHAUTOAIR]

I thought about that, but I also thought you would only boost up to about 10-11psi with the Y hooked backwards.

Brett

 

[UNGN]

With stock heads, you'll need 17-18 psi before a TA49 is any faster than a stock turbo. Below this, it's wash/slower than stock.

 

[dsa87gn]

Originally posted by UNGN
With stock heads, you'll need 17-18 psi before a TA49 is any faster than a stock turbo. Below this, it's wash/slower than stock.

wow..is that correct ?

I had always thought the number was much higher 21-22psi

 

[UNGN]

Originally posted by dsa87gn
wow..is that correct ?

I had always thought the number was much higher 21-22psi

It depends on the car. At TA49 works great at 20 psi and above (where the stocker is running out of steam), but the better your heads flow, the lower the crossover point.

I was running 12.20-30's with my stock turbo at 18 psi, bolted on a TA49 thinking I was going to set the world on fire, set it on 17 psi , ran 12.80's. Set it on 18 psi, ran 12.40's. It wasn't until 20-21 psi that it would dramatically pull away from a stock turbo (.2 or more quicker) and by 23-24 psi, it should be at least .4 quicker.