928ntslow

I wanted to get some kind of true increase for a GTS on paper as to what the addition of just an X-Pipe would do for a bone stock GTS. The only previous modification was an RMB.

We did a baseline a few weeks back and came up with some nice solid numbers to start with. The car made 313rwhp and 332.6 ft lbs. We did a few runs in 4th and in 5th and I seem to recall a run in 5th where the car produced 338.X ft lbs, but none the less, the numbers shown below are good enough to give an idea of where the (this particular GTS) GTS cars start from.

We were only able to pull off a run and a half before we experienced some technical difficulties which cut our time short. However, even though we got off one real recordable run, there was a decent increase for a bolt on cat swap with an X. The new numbers were 330.7rwhp with 353.6 ft lbs. Not bad for a bubble butted fat lazy pig Incidentally, even though its on rollers, I still get a kick out of watching the speedo sweep 180 before I back off the throttle.

I posted the dyno sheet below...sorry for the poor quality, we were kind of in a hurry. I think if we had more time, we could have come up with some better increases. Seems the mixture is running a wee bit rich and could bust loose a few more ponies after the A/F is dialed in...maybe Sharktuned. We'll continue this in a couple of months or so when time permits.

BTW, the flutter you see on the new curve was part of the technical difficulty we experienced. I would expect the next set of runs will look smooth again.

davek9

Wow that is easy bolt on power, please clarify "for a bolt on cat swap with an X.", did you replace the cats w/the new hi flow ones? Or are you using the stock ones?
Wonder if another ~8 hp is possible w/o the cats.

Thanks for sharing

PorKen

This screengrab shows the (5-speed, X-pipe, no cats) GTS's tire shredding torque with purdy colors!

This was with 90°+ intake temps, too - I couldn't even break 300 rw this day, with my S3 auto.

It was running way rich on top, maybe old MAF? A bit less fuel would likely take it to 340+ rwhp, I reckon.

Chuck Schreiber

Which X pipe? Roger/Dave Lomas?

pcar928fan

Both of my auto GTS's (one w/ RMB) with no tuning on them have only done 286 rwhp and 308 rwtq... How did you get that kind of power out of your GTS? Certainly the 5spd is a BIG help vs. the power robbing auto, but still I would think my numbers should have been slightly stronger. My '88 S4 w/ RMB did 266 rwhp and 267 rwtq on the same rollers and roughly the same hot days for each of those...

Peter F

I was thinking the same thing?
If the car is original it is amazingly high numbers even for a manual.

/Peter

RKD in OKC

You keep that up, you gonna make me get an x-pipe

IcemanG17

Keith
Those are GREAT numbers.....for a stock cam GTS.....maybe yours has GT cams?

ROG100

IIRC my GTS (Auto) was 285rwhp so those are amazing numbers.
Which X pipe did you use?

Ketchmi

He has one of ours...I think that there is more on the table but that is one strong GTS!

Tom. M

Louie's dyno isn't a dyno jet..but I think he can do the conversion... Were these corrected numbers? Either way...yes..likely the strongest stock GTS out there as the only other one I saw had around 305hp and 310 ft-lbs and that was done by Devek at one of their events way back. Garth Hadley (Tom Dingwalls now) was around 335 or so HP..don't remember the torque and he had x pipe and GT cams..

morganabowen

Hi keith,
Those are outstanding numbers for a GTS with minimal mods That is one sweet car you have Is you car chipped

pcar928fan

Rog, you and I are right at the same place...nearly exact. My '92 was 283 and my '94 was 286...

Ketchmi

I got Big's GTS up to 303rwhp and it's an auto...was disappointed. I was hoping for more.

cold_beer839

Dave,

I am about to buy a '93 GTS and I will be putting that X-pipe I got from you on it.

Wonder where in Raleigh I could get a dyno run before and after.