924Board.org

[Peter]

The new issue of 911& Porsche World has an article about the Piper camshaft & camgear that was authorized by the promoters of the 924 races (forgot its official name) in Great Britain.
Basically, the promoters wanted the participants in the 924 races to have more power so they allowed the introduction of non-stock cam& gear. The article goes into duration and lift specs, along with installation procedures, with plenty of great pictures.
The designers claim an increase of 12bhp on a standard (Euro to you and me) 125bhp 924. However, to get this power the cam gear MUST be fine tuned on a dyno, otherwise you will get far less power.
The write-up seems very credible as the cam & gear is marketed directly to racers who are in the best position to debunk false claims of horsepower. Anyone want to buy a Tornado air system or slick-50, guaranteed to make 5-20 more hp?
I do not have the article, but if somebody does, maybe we can post the specs and compare them to some of the "performance" cams sold here in the States.
-Peter A. Holiat

[Richard]

I am currently researching cams for my '81 and also read the article on Piper cams. I tried contacting the so-called U.S. distributor in Nashua N.H. but they said they no longer carry them. I wrote the specs of the cam down, and boy, compared to what I see offered around the Piper cam is one hot puppy. What I'm tying to say is I can't believe it only gives 10hp or so. I mild street cam should do that easily, and they are just a little hotter than stock, say 260. The Piper cam's duration is 284!. Of course maybe the lifts where the duration is taken from is different. Anyone out there have a favorite cam? I just want to warm things up bit, keep good powerband and gas mileage. The Integral "improved stock" or "stage 1" looks promising. They are ground from new billets so you can use stock lash adjusters. Cost $330

[Richard]

Oh yeah, here are the specs:
Intake opens 34 btdc
Exhaust opens 70 bbdc
Intake closes 70 abdc
exhaust closes 34 atdc

Inlet and exhaust duration 284 (don't know at what lift) Lift .461 on inlet,.460 on exhaust, Full valve lift at 108 atdc for inlet, 108 btdc for exhaust.

I thought the article said this cam allows the 24's to run with the 44,s.

[HRK]

I have one cam grinded in Piper Cams for 931 lying in unused ported 931 head in my appartment storage, waiting for garage, car, motivation and time.
I may be able to find papers which came with cam, stating duration and other stuff.
I can measure base circle and lift from it if needed.
Idle was like stock and car was quick with stock boost, this head and intercooler.

hrk

[Vince Ponz]

Careful guys. A cam that is too hot will kill your street driving. I had a high lift cam put in about 5 years ago and I could not launch under 2k RPMS. Then it would stall at the wrong time. It was so bad on the street that my two sons refused to drive the car. I took the cam out.
On the good side RPMs from 4k to 6K took about a second. Very fast on the track but a dog on the street.
I don't think a cam gives more that 10 Hp. Add a header and maybe another 5-8. Cam gear 2-3.
After this remove weight from the car. Then go on a diet yourself. Hey, twenty lbs is 20 lbs.

[ricomartinez]

Vince,
How much is too much? Do you remember some of the numbers? Did it pass emissions?

[Joes924]

Interesting vp.. a question I have to ask I have ,Is my head gonna function in your opinion is it going to work. I have only 2 more. I ported it, the exhausts has been ported all the way thru and polished . The intakes with some port work done in the cumbustion area not polished its still rough but work has been done there,
not really recontouring mostly enlarging around the area of the guides and enlarging from the valve opening making the opening straight up to the curve to the guide and enlarging the guide area smoothing and adding area its not gonna be cc-ed or flow tested at all the curved area the short radias side was smoothed getting rid of sharpness.?:::? Is the operation going to be a succcess ..I dont know its going need to be analyzed . I post a pic when its ready to
put it together should be in 2weeks as far as the valve train.

_________________
924Porsche1979JoeD.

[ This Message was edited by: Joes924 on 2002-04-22 04:39 ]

[larso]

I agree with vince unless you are using the car as a track car. It's not very fun to have a car that stalls at the stop lights. It is even worse if the car is an automatic, because you can't control the RPM when you take off. You might just want to up your idle RPM with a new cam to solve the stall problem. But if you drive around town quite a bit then the cam is no fun. Then again these cars have manual steering LOL.

[Joes924]

Ive been thinking about that 2 grand launch thing.. that would not be good all.

[Vince Ponz]

Cam regrind was 477 288

[ricomartinez]

Is that 0.477 inch lift and 288 degrees duration (at start of lift)? Lumpy idle? Emissions? Who did the re-grind? How much? Good quality?
Rick - The inquisitor...

[Joes924]

Got mine yesterday question .470 valve lift
274 duration.