Whipples, Pulleys, Tunes

[Yukonranger]

OK, I am at the point where I want to add more power. My driving is mostly on very open roads in MT where you can pay speeding fines on the spot and they don't go on your record and accrue points:biggrin. I DON"T want the car louder and I want it to run on 92 octane. The options seem to be:

Tune 40hp
Tune + Pulley 90hp
Whipple +150hp (or more)

The car's weak points are:

Grip
Cooling

Other concerns are:

Clutch torque capacity
Transaxle torque capacity

Given that I want don't want the car louder, is the Whipple the answer or am I going to be limited by the stock exhaust? I would be willing to install headers but am unsure what I would gain with the stock cats and muffler. A tune with or without pulley is dramatically cheaper on a /hp basis.

I am young enough to want more power but old enough to know that more power is not your friend when you don't have enough grip....

 

[jaxgt]

I had a pulley and tune done by one of our great forum sponsors. I dyno'd around 600hp. Car handles great, and I have not noticed any grip or traction issues. I haven't done an exhaust, but am considering the Borla.

Sounds fun to live in Montana ... especially this time of year

 

[Yukonranger]

Did you dyno the car before the changes? Is the 600hp rear wheel hp or has it been "corrected"?

I live in N Idaho but MT is less than 30mi from my hanger where I keep the GT.:biggrin

I had a pulley and tune done by one of our great forum sponsors. I dyno'd around 600hp. Car handles great, and I have not noticed any grip or traction issues. I haven't done an exhaust, but am considering the Borla.

Sounds fun to live in Montana ... especially this time of year

 

[Empty Pockets]

If I recall posts on this subject correctly, there seem to be no clutch issues if HP levels are kept below 700. It's when one goes over that level that pblms are more likely to occur. ( But, even then if you don't have your foot in the radiator CONSTANTLY the stock clutch should last quite a while.)

That said, I don't recall reading posts regarding ANY tranny pblms at all caused by high HP levels. The Ricardo unit itself is pretty beefy.

Regardless, as you rightly pointed out, getting the HP to the pavement is the limiting factor. 'Not really a whole lotta sense spending money to build HP levels BEYOND what tire manufacturers can glue to the road. (Unless braggin' rights are factored in, of course!!!)

Re: noise level. Most would pbly agree one of the "X" pipes would likely be the way to go.

 

[cobrar1339]

I watched some guys dyno with various adders. It pretty much matched what you suggested for power.

The P/T were slightly over 600 RWHP on a cool morning at sea level. As I recall they ranged from 612 - 625. These were pretty ideal conditions. But, all were also running 91 octane tunes. You will likely make more with a higher octane tune.

There was a tune only car that made some big numbers for a tune, right at 580ish.

All P/T A/F's were very safe and maybe too fat. But it's that last enth that get's us in trouble. The tune only was much less on the fat side in comparision, but still very safe.

As I recall, the pulley cars were all Heffner and the Tune only was Accufab. Torrie also offers a tune only that I have heard good things about.

As for exhaust, the cat backs are worth about 10rwhp from what I have seen and read. I would say Accufab may have spent the most dyno time on a system and they say 10 Rwhp for the X cat back. And the Long tubes 25-30+, but louder than your Requirement ( note they are not loud in the car just cruising), but outside they do draw attention.

 

[jaxgt]

I didn't dyno my car before the mods.
It dyno'd right at 600hp at the rear wheels on a fairly hot summer day. Work was done by one of our sponsors - Tony at HP Performance in N.Florida. One of many great folks on the forum.

 

[TEXAS GT]

The Whipple should add closer to 200 hp if you get it professionally installed and tuned with a decent x-pipe. But it's about $10 - $11000 for the full kit.

I skipped the pulley and went straight to the Whipple and never regretted it. I think most of the guys here (if they would be honest about it) would love to have the Whipple over the pulley but it all boils down to your "power to peso" ratio.

And then there's the twin turbo...:eek

 

[JTHennessey]

Twin Turbo.... Yummm....

Feel free to give us a call at Hennessey as well
http://www.hennesseyperformance.com

979-885-1300

JT

 

[Yukonranger]

Thanks for all this information. I guess an obvious question is what RWHP a stock GT makes for an apples to apples comparison? Also, how loud are the X pipes compared to the stock muffler?

I watched some guys dyno with various adders. It pretty much matched what you suggested for power.

The P/T were slightly over 600 RWHP on a cool morning at sea level. As I recall they ranged from 612 - 625. These were pretty ideal conditions. But, all were also running 91 octane tunes. You will likely make more with a higher octane tune.

There was a tune only car that made some big numbers for a tune, right at 580ish.

All P/T A/F's were very safe and maybe too fat. But it's that last enth that get's us in trouble. The tune only was much less on the fat side in comparision, but still very safe.

As I recall, the pulley cars were all Heffner and the Tune only was Accufab. Torrie also offers a tune only that I have heard good things about.

As for exhaust, the cat backs are worth about 10rwhp from what I have seen and read. I would say Accufab may have spent the most dyno time on a system and they say 10 Rwhp for the X cat back. And the Long tubes 25-30+, but louder than your Requirement ( note they are not loud in the car just cruising), but outside they do draw attention.

 

[TEXAS GT]

My car stock was 518 hp. After the Whipple and x-pipe it's 732 hp. The twin turbo is 850 on pump gas.

One thing I've learned from reading this forum is that everyone has much different taste in exhaust sound. I tried the Borla first but it wasn't much different from the stock sound. The forum member I sold it to loves it. I've been very pleased with the X-pipe,(either Accufab or Heffner) but no one can really tell you what pipe sounds "best". Only you can determine what's best for you. The best advice I can give is to listen to as many as possible before you decide, but if that's not possible, take your best guess and be prepared to try a different system if it doesn't satisfy you.

In my opinion, anything sounds better than stock.

 

[Black GT]

Mine was 552 stone stock. Then 642rwhp pulley tune. Then 743rwhp Whipple.

 

[SteveA]

Mine was 565 stock and 680 with a pulley/tune and MMP X-pipe. The tires quickly became the week link. After a set of PSII's I became very happy with the set up.

 

[Yukonranger]

Could you tell me what pulley size or boost level you are running and also what octane and whether you live at sea level. Thanks again.

 

[SLF360]

I had a pulley and tune done by one of our great forum sponsors. I dyno'd around 600hp. Car handles great, and I have not noticed any grip or traction issues. I haven't done an exhaust, but am considering the Borla.

Sounds fun to live in Montana ... especially this time of year

Me too. HP Performance (Tony G) did it, and worked great ! Highly recommended tuner and shop

 

[SLF360]

'Not really a whole lotta sense spending money to build HP levels BEYOND what tire manufacturers can glue to the road.

EP,

... but if you are looking for fast train escape acceleration in fourth gear and beyond, extra power will go to the floor ! :biggrin

I love to let the Porsche Turbos on the highway be totally stunned by the zoom, zoom and away our GT's tuned are capable off... If wiyth a great exhaust they also get a flame in the face, when shifting down from cruisy fourth to third, trust me, spoke to one after he had me in front.... leaves impression like first time sex...:biggrin

 

[HOOKED ON GT]

From what I can gather Fords tells us the GT makes 550hp.
it seems like it's more like 600hp from the factory when looking at rear wheel HP numbers you guys are getting.
What's your thoughts on the engine power of a stock GT.

Go Whipple and your at 750 - 800hp at the fly?

 

[nota4re]

From what I can gather Fords tells us the GT makes 550hp.

Exactly. And if you remember the early literature, Ford was claiming 500HP but managed to eek out a few more ponies in the final config. My view is that this is an accurate number and if Ford could have said 600 or 650, they certainly would have loved the bragging rights.

The differences that you see cited above are differences that you typically see across different dynos. It is difficult if not impossible to compare dyno-generated HP numbers across the internet with any kind of accuracy. A dyno is a very good tool to give you a baseline number from which you can see the benefits of various modifications.

 

[HOOKED ON GT]

Has anybody tested the engine on just an engine dyno?

 

[paul b]

Has anyone found significantly different H.P. from 21 lbs. of whipple boost and 21 lbs. of twin turbo boost. Is there any dramatic parasitic loss or power gained under the curve?

 

[tmcphail]

Has anyone found significantly different H.P. from 21 lbs. of whipple boost and 21 lbs. of twin turbo boost. Is there any dramatic parasitic loss or power gained under the curve?

Yes but that is dependent on how fast you spin the blower. Average Whipple car at 19psi is 750whp my car at that same pressure 900whp.

But the whipple setup will make more power down low where the turbo's can't and the turbos will make more power up high sans the parasitic drag. It all comes down to what you want to do with the vehicle.