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Mitsu, you mention DBilas. Are you located in Germany? Are you on 928 PFF?
292.09 is 928S4 Weltweit (rest of world) intake camshaft cylinder bank 5-8.
Åke
→Ake, No I don't reside in Germany, though I used to travel to very often. Like Fraunhoffer institute etc.
So from what Dave posted above, do I have S3 cams that have been reground?
Looks like it. Measure the base circle, and then from the bottom of the base circle to the top of the lobe . . . the difference will be the lift. Pics of the stamped numbers on the end, and a pic of all the cams because one should have a mod on it to allow fitment in GTS or S4. With that info it might confirm the likely origin of the cams you have.
Hi all, I found an info. on the cams from Dbilas Dynamics Germany that I would like to share with you.
They offer regrinds for 928 32valves as in the following;① The camshafts from the S4 and the GTS are the same (inlet 254° with 9,5mm lift and exhaust 240° with 8,5mm lift)
② At 1.0ｍｍ, oemS4 have inlet 209° and exhaust 194° and Dbilas Dynamics GT spec. > inlet 222° exhaust 212°
③ They can also grind another profile:
@1,00mm
inlet 268° with 10,3mm lift 234°
exhaust 260° with 9,4mm lift 220°
I need to confirm again but they are welded cams and induction hardened ?
As soon as i confirm the details, I will ask them to regrind my cams(a set of S4 cams 271-274 00 bought from ebay) Thanks to you all, now I know how to read cam specs !
Also, I am convinced that GTS cams are the same with S4 cams. That is a piece of information I wanted to know.
Have you made further inquiry about Dbilas cams? I’m intrigued by those too.
hi, i actually had the cams made by dbias. 222°@1.00mm lift the same profile for in and exhaust. i wanted to have the base circle the same with the original, but because i used the S4 cams as base, i was not able to make the base circle the same to have the higher lift of GT profile. so the baes circle was cut down. So i decided to have inner shims on top of valve stems so that the original lash adjusters will work. cams are already installed and now i am working on the exhaust system. by the end of this year, i should be able to fire up and check the power. once i know the data, i can share my experience with you guys. if you have further questions, please feel free to ask. Cheers!
I installed GT cams in my GTS and they made a significant difference. With four hole, 24 lb. injectors it dyne'd at 339 HP to the rear wheels. The only other mod was aa x-pipe exhaust system with an RMB.
I installed GT cams in my GTS and they made a significant difference. With four hole, 24 lb. injectors it dyne'd at 339 HP to the rear wheels. The only other mod was aa x-pipe exhaust system with an RMB.
When you say GT cams, do you mean OEM Porsche GT cams, or S3 cams, or another vendors cams?
Would you mind sharing the dyno chart? I am assuming you sharktuned it as well. It would be interesting to see your sharkplots (fuel and ignition) from the runs. I am curious to understand where on the HP and Torque curves the cams are providing increases. Is it all across the RPM range or is it mostly at the top end above 5000RPM?
my GTS has a very similar setup to Jim's. When I went on the dyno with it in 2017 it had the following modifications:
Louis Ott stainless x-pipe with metal high flow cats
24 lbs four hole injectors
RMB
Sharktuned with PEMs for LH and EZK
All new ignition components (wires, rotors, caps...)
Porsche GT cams
Car ran great back then. Now even better with the EZK-S EPROM from Ken (it uses my Sharktuner mapping as a basis)
Below the results from April 2017 at the rear wheels. Biggest difference between Jim's and my GTS: mine never burned oil. I think that GTS with high oil consumption have a tendency to knock quicker and with this, EZK is retarding the ignition all the time. This will result in less power.
Although it says engine and wheel power, the curves show the power output at the rear wheels.
Barking dogs in the background, that's Romania for you . The graph above is from the third pull (minute 2:30), the sound outside with the RMB was amazing!
Last edited by Schocki; 10-25-2023 at 03:28 PM.
Reason: Video added
hi, i actually had the cams made by dbias. 222°@1.00mm lift the same profile for in and exhaust. i wanted to have the base circle the same with the original, but because i used the S4 cams as base, i was not able to make the base circle the same to have the higher lift of GT profile. so the baes circle was cut down. So i decided to have inner shims on top of valve stems so that the original lash adjusters will work. cams are already installed and now i am working on the exhaust system. by the end of this year, i should be able to fire up and check the power. once i know the data, i can share my experience with you guys. if you have further questions, please feel free to ask. Cheers!
The downside to this approach is that regardless of what the cam grinder does to the camshafts, they can not alter the lobe separation of the S4 cams to equal that of a set of GT cams.
They can, of course, remove enough material to achieve the same lift and duration, but the lobe separation issue is a huge problem and will result in less than optimum results than if you had started with an true set of GT cams.
Thanks Jim, for sharing your experience. Once i have my measurement, I will share the result. i have the headers, big throttle, EZ-k, exhaust, ported intake, so hopefully i get a similar result!
Hi Greg, yes, I searched for GT cams but they are so difficult to locate. i had to settle with S4 cams. I hope that i can keep up with latest sport vehicles.
When you say GT cams, do you mean OEM Porsche GT cams, or S3 cams, or another vendors cams?
Would you mind sharing the dyno chart? I am assuming you sharktuned it as well. It would be interesting to see your sharkplots (fuel and ignition) from the runs. I am curious to understand where on the HP and Torque curves the cams are providing increases. Is it all across the RPM range or is it mostly at the top end above 5000RPM?
My cams were Porsche GT cams. Unfortunately I gave the dyno charts to the new owner when I sold the car. Yes it was shark tuned also. From memory the added power was almost all across the power band. Mostly I remember smiling so big with the outcome.
The downside to this approach is that regardless of what the cam grinder does to the camshafts, they can not alter the lobe separation of the S4 cams to equal that of a set of GT cams.
They can, of course, remove enough material to achieve the same lift and duration, but the lobe separation issue is a huge problem and will result in less than optimum results than if you had started with an true set of GT cams.
What about the 85 cams.... as i did... seems they had near the same power, maybe 10hp less.
btw........ i have the GT cams from the holbert engine... missing a few teeth though... anyone interested?
02-04-2022, 12:55 AM
. The graph above is from the third pull (minute 2:30), the sound outside with the RMB was amazing!
