cold_beer839

Any GTS owners that can give some info on what non-stock cams they are running in their 5.4's? I think Roger and Jim had put some S3 or GT cams in theirs. Anybody running custom cams?

Gary Knox

David,

I'm still running stock cams in mine, but will take out the GTS exhaust cams and replace them with S4 exhaust cams this winter. Supposed to (according to Louis Ott and Adam Birmbaum) increase horsepower and torque.

Gary Knox

Chuck Schreiber

David,
After all my "have to's" I'll go w GT cams (Jim Mayzurk) or the ones Roger has. (Reground)

Their cars w cams and Sharktuning are CONSIDERABLY stronger than my GTS w X-pipe and RMB.

I think Jim Did 340hp at the rear wheels with the GT cams.

Jim M.

My GTS with stock GT cams dynoed 339 HP before shark tuning and before the 2.5" mandrel bent exhaust system with X-pipe. Roger has the S3 cams in his Rogerbox, but he hasn't dynoed yet, only some shark tuning.

pcar928fan

^^^^^
That is what I want to do to my '92 as well!

928mac

Has and flow testing been done for the best flow vs Ci ?
I have not looked at any post at all to see who has what for cams and the dyno specs of before and after.
There must be a range from stock to full race where a guy could pick a middle ground of lift/duration?

ROG100

Mine are the "Jim Morton" S3 cams with a "street grind".
Totally different car with the new cams.

andy-gts

I had gts cams with the base circle grind and went from 318 to 334 rwhp with sharktuning.....

then put on 5 psi and reached 426 rwhp.

I was told the lobe angle seperation was the limiting factor in the cams.

andy

IcemanG17

Tim got around 330whp with GT cams + X pipe in his GTS too....

cold_beer839

340 rwhp is a respectable N/A number in my book!!

Shark_Week

nice topic
been wondering lately of what to do next, performance wise, to the GTS. at the very least new exhaust. david which short throw shifter are you using?

Chuck Schreiber

Jim,
You and Roger Added 24# injectors as well correct?

Jim M.

Correct! We both also have 928sRus intake spacers, however the dyno didn't show any real improvement with them IIRC.

Jim Morton

FWIW, the cams I provided Roger are the same cams I ran in my own GTS and the same ones installed in Dennis Kao's S4 engine. The cam profiles used are from Dema Elgin's of Elgin Cams and were developed as a regrind profile that fits on a good set of S3 or GT cores, staying within the working range of the hydraulic lifter. As we know, 928S4's and later have 4 cams and regrinding 4 cams is a lot more labor than what's common with a pushrod V8.

The cam profiles are very streetable yet fit the flow needs of the 928 4V heads. 24# injectors are recommended if using stock fuel pressure. I tried the 30# injectors and needed to do quite a bit of re-mapping for idle and off idle transitions.

As another FWIW, there is a lot more to cam profiles than simply reducing base circles to achieve more lift or even knwoing that you need more lift as a point all in itself.

For anyone considering cam changes, know that you are altering the basic event timing governing the 4 strokes of the engine. Retuning of fuel and ignition maps should be consdered a given when doing a cam change. When these engine are retuned with revised valve event timing, valve lift values along with fuel and ignition map edits, the results can be asounding from the driver's seat as long as you know how to tune 4 strokes. For those curious, please search for Dennis' engine posts and review.

Enjoy.

mark kibort

why not just put in the intake cams from an 85? get more lift, more power and if you think the exhaus cams for the S4 are better, then stick them in too.