n/a cam on a turbo

nynor · 12-01-2005, 12:35 PM

lately, i've read about this. has anyone done it? what about an 8 valve 928 cam?

Zero10 · 12-01-2005, 01:58 PM

I run a late N/A cam in my turbo. It had serious issues prior to this, and an unknown cam, but I can say for certain that the turbo spools up very quickly with the N/A cam

nynor · 12-01-2005, 02:46 PM

interesting. any thoughts on why this would be?

Zero10 · 12-02-2005, 08:07 AM

1 degree more exhaust lift, 6 or 7 degrees more exhaust duration.
Intake is the same.

nynor · 12-02-2005, 09:00 AM

so the exhaust exits the cylinders faster?

AaronM · 12-02-2005, 11:51 AM

Are there any other reprecussions from running a N/A cam in the Turbo?

Zero10 · 12-05-2005, 10:28 AM

People argue that the extra exhaust duration causes overlap, meaning lost boost. However, I have seen diagrams of the camshaft, and I don't believe there is any overlap. If there is, I sure am not having any boost problems as a result of it, nor any exhaust backfiring (which would be indicitive of this problem).
So, IMO there is no downside. And yes, the purpose is to help the exhaust leave the cylinder faster (higher exhaust velocity = quicker turbo spool) as well as force that little bit more exhaust gas out of the cylinders.

nynor · 12-05-2005, 10:41 AM

oh boy! this is going to be fun!

Zero10 · 12-06-2005, 10:05 AM

Keep in mind this is not going to be a night-and-day difference. Perhaps not even enough to really be felt in the seat of your pants, but I do notice faster spool-up, which is always a big plus

Porsche-O-Phile · Porsche-O-Phile's Garage

I've heard you can use a 928 cam as well, but I believe the firing order would be different (wouldn't it?)

AaronM · 12-06-2005, 06:01 PM

Quote:

Originally posted by Porsche-O-Phile
I've heard you can use a 928 cam as well, but I believe the firing order would be different (wouldn't it?)

Depends. If the 928 V8 was a flat-crank V8 then the firing order shouldn't be different.

hacker-pschorr · 12-07-2005, 03:27 AM

A 928 cam will not work in a 944. Many have discussed doing the opposite (944 cam in the 928) on Rennlist:

http://forums.rennlist.com/rennforums/showthread.php?t=230371

http://forums.rennlist.com/rennforums/showthread.php?t=104624

por944trs · 12-07-2005, 05:39 AM

Results improve with bigger turbo

, I did this as well when I went to a k27/8 , I noticed a difference.

Tapage · Tapage's Garage

Quote:

Originally posted by por944trs
Results improve with bigger turbo , I did this as well when I went to a k27/8 , I noticed a difference.

K27/8 is a bolt on upgrade .. direct replace for a K26/6 factory turbo, with no other modd needed in the computer or inyectors .. ?

por944trs · 12-08-2005, 09:38 AM

Lots of other mods, just including my experience with this one.

Tapage · Tapage's Garage

Quote:

Originally posted by por944trs
Lots of other mods, just including my experience with this one.

Good to know .. I'm not in this way right now ( not yet hahaha ) after my first step ( a chip ) figure some info about that ..

thanks ..

por944trs · 12-11-2005, 11:12 AM

Contact John @ Vitesse Racing when you are ready he has a great setup

Pb_Foot951 · 12-12-2005, 09:41 AM

From my research it appears the 944 turbo uses the same cam shaft as the early and mid 944 NA engines. What model year did the cam shaft change? The later cam is supposed to spool your turbo faster. Are there any aftermarket cams out there that are better for use in a street car?