968workaholic

Didnt want to hijack the other thread, but was curious to hear what "sacrifices" you speak of with performance cams? Unless more power is considered a "sacrifice"?

968workaholic

Nothing?????? Figures........

Stephenwz968

Who is actually running a different grind on the 16V head? I know they're "available", but has anyone used them with success on an N/A 968?
Steve

Fox944

really no sacrifices, with the exception of using more fuel. more power accross the entire range, especially mid & top end.

Cams make as big a diff as intake/header/exhaust combined.

StewHatch

Am I correct to assume a high perf. cam setup may require an improved header / exhaust/ intake to fully realize it's potential? My guess is that changing cams will give you a more noticeable performance gain simply because the sum total of all the additional improvements would be greater. How much HP / TQ can you expect by installing a streetable grind and the appropriate additions? I always thought that just adding aftermarket exh / header might get you an extra 5-10 hp depending on the setup you choose. I honestly don't know for sure. Can you just swap cams and get similar gains without changing anything else?

rdhayward

I'm not an authority by any means, but for engines I've built the considerations for cams are usually: (a) What is the intended power range - is it for a screamer or a rock-crawler? (b) How much smooth idle are you wiling to sacrifice - is it for a daily driver (DD) or a designated toy (DT)?

Fox944

Stew, you are correct in assuming that you would require basic bolt ons to realize he full potential of cams. You will also need a remapped ECU. Likewise with the basic bolt on's (will need a remapped ecu to realize all the potential). Once your car has a header/full exhaust/intake, Cams are the next step. There are other modifications you can have done, but they wont give you nearly the same gain cams will. All depends how much power you want to make and how much money you want to spend.

The diff btwn a car with header/exhaust/intake and one with with all that plus cams is similiar to the diff btwn a car with no modifications and one with header/exhaust/intake (in regards to power).

Damian in NJ

http://www.jmengines.com/index.htm

Milledge products are available from no-one else, he designs, manufactures, and tests the products in house and has a stellar reputation in our Porsche world.

Stephenwz968

I'm really not trying to be a jerk, but has anyone actually installed cams on our cars, and what were the results? Seems like a lot of talking about what they would do, but nobody has actually posted anything thing that they have done, or observed first hand.

Lemming

I believe that Fox and Pablo are both running "performance" cams.

Damian in NJ

I had Milledge cams on my 944 and saw 14 hp gains, as I remember torque went up as well. I'd imagine that similar percentage gains would be seen for the 968 motor.

Just remember any of these mods won't perform as well on a tired motor-as learned over on the uk board, 968 heads really respond from a refreshing at pretty low miles-75K seems to be the mileage mentioned as I recall. Read the bit below taken from the uk board.


A lot of people have been asking about doing 944S2s and 968
models recently. As always I have been giving an honest
answer as regards doing these cars and it goes like this:-

There is a very considerable performance-sapping issue with
these engines and that is one of dynamic valve seat leakage
The valve guides are very short indeed and the valve head is
a long way away from the guide. This means that only a very
small amount of valve guide wear causes a lot of axial
movement which knocks the corners off the valve seats. This
causes the valve to 'rattle' around on the seats as they
close and this causes a considerable amount of compression
loss and disrupts the next charge in the intake port.

This shows up on the dyno as a loss of power, and slightly high
hydrocarbons particularly at higher RPM, and can be as much
as 30bhp. Our race 968s all had their heads removed and the guides
and seats done half way through the race season to keep them
fresh and on maximum allowed power.

Due to the above, it is far better to make sure that your
engine is in tip-top fettle before considering having the
chip mapped. I know that it is not in my best interests
commercially to say this, but I would rather you knew before
hand than have you say to me afterwards that I might have
mentioned the valve seat thing sooner! Honesty is the best
policy but not the most profitable!

Wayne Schofield

Fox944

Stephen; I have RS Barn's latest performance cams in my car, my observations (mentioned in the posts above) are first hand.

968workaholic

Link edited Bob R

Another source for performance cams as well as Milledge.

Stephen, every car that I have put cams in has had no problems and has increased hp and torque.

Stew, any internal modification would produce more of a gain if the means by which the air/fuel goes into and escapes the motor is more efficent.

Damian, its true that the best thing to do before going the performance route with anything is to make sure that the motor is in the best condition that it can be in.

The point of the thread was to address what sacrifices that some were concerned about as well as for everyone to gain some knowledge on the topic of cams in general. Porsche couldn't make the engine as powerful as it can be because the mpg would be terrible, and most people would want to buy a huge gas guzzler off the lot. For some that are tired of the same power and want some more pep cams as well as bolt on mods are an option.