SpeedBump

98 octane is the equivalent of 93 octane in the states so not a huge jump. I believe 91 is the max in places like California without searching for someplace carrying race gas

Carl Fausett

Yes, its quite possible that the 944 S2 would have greater before-and-after gains (if thats what you are looking for) but maybe not higher numbers ultimately.

H2

So, am I hearing that the variocam is deactivated for the supercharged engine? I assume this would be for the same reason that Porsche didn't use the Variocam on their turbo 968. BTW, what is the reason the Variocam head isn't used?

There's a guy on the 928 Forum (Sterling) that retrofitted 968 Variocam heads to his 928.

H2

jthomson

Hi all,

I stumbled onto this thread a few days ago and as a new '94 968 cab owner( Gawd, I LOVE m'car!), am very excited about Karl's (if I may) s/c! As someone who is not that technically or even mechanically oriented my question is; will stock components esp., trans, clutch and head take the increased performance w/o mods?

Thanks, JT

Airflite40

co carl is saying that he left the variocam working as stock.

sterling's car isnt supercharger and its a stroker iirc.

Carl Fausett

Yes, the Variocam is functioning as normal on that dyno pull.

Someone mentioned chips.... I looked up the Excellence Magazine, May 2006 where they chipped a 968. They only got 12 HP.

Here is a little video I just posted about this kit:
http://www.youtube.com/watch?v=nr1F_z8bi1I

Damian in NJ

JT, welcome to the best and most open, well moderated 968site. Tell us about your car in new thread, we love to welcome new owners here.

Mark944na86

Yes, this is what I was thinking of.

FRporscheman

Without doing anything fancy with variocam tuning, the best thing to do is disable the variocam so there's no valve overlap. Instead of a new chip, how about we just unplug it ourselves? I'd be interested to see the results of this SC kit with disabled variocam.

Also, it occured to me the intake manifold (which was designed to resonate for the NA induction) may be detrimental with forced induction. I'd also be interested to see the results with an S2 intake though I don't expect this to actually happen, because the typical 968 owner won't want to change an intake manifold.

Either way, superb work Carl, and thank you for your dedication.

Duke

I'm not sure why you are so concerned that the varicam would be negative in this application?
The boost is low and since it's not a turbocharger there is no additonal back pressure so gas reversion should not be a problem either.
My last 968 turbo engine (16v) was dynoed by the prev. owner to 495 rwhp at 1.3 bar boost with stock head and variocam in stock configuration.

FRporscheman

I'm just curious, did you ever dyno it without variocam?

I'm just looking at the timing chart where it shows valve overlap with variocam on. It seems to me like boost can escape during the overlap. I'm no engine tuner so I'm not claiming anything, just sharing my thoughts. The bottom line is that it's another variable, and very simple to toggle, so it should be tried. We can sit and discuss why or why not VC is good or bad with a supercharger but nothing will be as definitive as a dyno run.

Riff

Looks great!!!! Hope the price is workable.

Any ideas what will be needed (other than MAF conversion) to run this on a S2?

RajDatta

Arash, 944S2 intakes do have resonance/pulse charge as well.

http://auto.howstuffworks.com/porsch....htm/printable

A quote from the website:
A revised intake system gave a “pulse charge” effect for more high-end power (it was noticed above 4,000 rpm) and a catalytic converter moved closer to the engine to shorten warm-up time for reduced emissions. An adaptive knock sensor and the addition of an on-board diagnostic system to allow tracing any intermittent faults in the Bosch Motronic engine computer rounded out the improvements. With all this, the big four now delivered 208 horsepower at 5,800 rpm in U.S. tune and 207 pounds/feet of torque peaking at a usefully low 4,100. And that was on regular gas, despite tight 10.9:1 compression.



Raj

Carl Fausett

I'm going to take the car back to the dyno tomorrow.

I want to get a dyno pull with the Variocam unplugged and see how it might differ.

Drives fine that way, seems a bit more linear and preictable, but the dyno will confirm or deny my assometer.

savvas944

tried chips for the 968 ,a weltmeister custom job to go with a kn filter, and was definetly imrovement over the std set up. the next one was a promax 7100 which seemed to have a bit more low down to 4500 rpm ,pull over the Welt meister chip.
the last one is a promax 7700 RT row chip which seemed to make a sudden jump in performance over the others., with power and torque way up through out the rev range and all the way to the red line.the claim that adds 22 bhp, was easily believed.

Carl--on the subject of the h.p figures and as an attempt to make more , is there possipility or uefullness to add an intercooler on the LHS of the car similar to the ones that Nissans s13-s15 use with turbo engines and massage the fuelling to match?

At the same time it may add some longevity to the engine . if it has to operate in high ambient temps for long periods of time.
these intercoolers are compact , and easily placed insid the available space.you may need to relocate the horns.