Josh B

Went by that same dyno this evening with some Porsche buddies. I borrowed a friends 968 and ran it to compare with my car. Pretty similar!

His car

Both cars

BikePilot

Very cool and quite similar indeed--a good thing, suggests fairly tight tolerance control over things like cam timing etc. (to the extent a sample of two can be extrapolated to a trend anyway).

Josh B

I've got a third 968 here in Atlanta that is nearby. Hopefully I can get that car on the same dyno - would start to get interesting at that point comparing the lines

odurandina

the stock resonator/muffler combos are terrible.

mikew968

notice the blue line power and see where it dips around 5700? Any idea why? the other car does not have the dame dip. I ask as my car has the same dip with no explanation.

Joel8005

That dip was present in the race car with a stock chip and one of the" plug and play" chips, we tuned and flashed a new one to even out the power curve and eliminate that dip.

Cheers,

odb812

Do you have the AFR chart for the runs? I'd estimate it's a little rich at the dip at 5700. I can't remember, is that where variocam disengages at full load?

Lear35A

I am hoping to get my supercharged 968 on this same dyno asap too. Having these datapoints is going to be great for comparison. Thanks Josh.

Kpoeltl

You cam timing is set incorrectly,.. that is what causes the dip,.. if it is set too far in the other direction it will be a rise (not a dip) at the same point.

Karl

Cloud9...68

Yes, there's been a lot of discussion about cam timing lately on this board - your comment on the power and torque dip on the OP's friend's car is further evidence that getting the timing correct on these cars, especially if there is any wear in the variocam unit, is a tricky process. Do you use the workshop manual method, or is there another method you recommend?

mikew968

Thanks Karl...good to see you on RL! Are you posting on the Cayman build?

Kpoeltl

I use the factory method to set the timing. I was just browsing the other day and saw this post and had information on it so I thought I would try to help out. I ran into this exact dip about 10 years ago on one of my race 968's. Set the cam timing to factory spec and you won't have a problem.

I haven't given any thought about posting Cayman build info but might do it when I get a bit more into the project.

mikew968

Thanks Karl. Looking for the next race car and am strongly considering a Cayman!