Cam Choice

[dos531]

So my clutch started slipping, and I figure while the engine is out this would be a good time to toss a cam in there. A 964 cam is probably the correct and easy answer, but this car is about the fun experience for me and ive always wanted the idle of a big cam. It's currently running 3.4 p/c with 7.5:1, 3.2 carrera manifold, Full bay turbokraft intercooler Sequential EFI etc. Will probably set it up for flex fuel while its apart as well. Unfortunately I am still on the stock heads, and I cant spend the money to do the top end properly right now, so thats staying. Gt2 evo cams? I should probably just call turbokraft but I figured maybe somebody here has another interesting idea.

[David]

I'll vote for the 964 cams. With a set up like you have, which is very similar to what I have, it revs so fast to redline, why make that last 1,000 rpm come any faster?

[pkabush]

LMK if you decide on 964 cams. I have a nice pair that’s had the pwr steering lobe ground.
I was going to use them in my 930 but decided on SC cams.

[dos531]

Yeah a 964 cam would make sense, but wont give me the idle I'm looking for.

[dannobee]

Depending on your pistons, the GT2evo cams might need eyebrows cut in the pistons for valve clearance. You need to check the exhaust side AND the intake side. The last one I put evo cams in was awfully close on the intakes, too. 0.025" is cutting it really close on the intakes and leaves no room for error.

[Black_Hat]

contact Chris @ TurboKraft

https://www.youtube.com/watch?v=s6c50hfnKfk

[dos531]

Originally Posted by Black_Hat

contact Chris @ TurboKraft

https://www.youtube.com/watch?v=s6c50hfnKfk

Yeah thats the sound i'm looking for.

[pkabush]

That beast sounds downright mean

[RarlyL8]

Those are GT2 cams with my exhaust. Two obstacles with those, one you have to relief cut the pistons and the other is it throws the torque curve to the right, harder for the tires to bust loose when the turbo hits.

[Black_Hat]

actually they are ,TK MODIFIED 965-S GRIND CAMSHAFTS -- better street & EFI use, more torque than 964 or SC .

strong bottom end - better than stock off boost, no stall , no sputter , no flat spots

I have a RUF K-29 turbo and it still has the same boost threshold as a K-27.

it does hit very hard but my wife can drive it to get groceries.

Still CIS with a RarlyL8 adjustable WUR, modded Fuel head, headers and muffler.

I've posted these before need to make new ones , the sound gets so many complements.

https://www.youtube.com/watch?v=URADTyXSo5I

https://www.youtube.com/watch?v=DhrHoGAKG2M

[RarlyL8]

Sorry about that, I had your cams listed as GT2 in my notes, totally different. Love the loping sound!

[1Bad86]

Well when I redo my engine I know what I'm going with now. I was considering GT2's but your car sounds awesome.
I'm still on the fence about going EFI but want to keep the CIS since it's a system I kind of know (the issues I'm currently having with it non withstanding lol).
EFI would be a new learning curve but that's where the power is at.
"Horsepower is expensive, how fast do you want to go"
I figure 475-500 whp should be enough if I go EFI. A flat fan conversion sure does look sexy as well but costs more than what I'll probably spend on the rebuild.

[pdqcarrera]

Curious, how much do you gain with all of the great mods without having ported heads? Would appreciate seeing dyno sheet.

[Black_Hat]

@pdqcarrera

I have seriously welded and ported heads and intake

http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/767012-forced-deal.html

I was @ 450 whp , I have since installed a modded fuel head for more fuel.Car is tuned but not dyno.

[JW2000]

I have gt2 cams efi. It doesnt have much of a lumpy idle, no where near close to the above video. Maybe my tuner just made it smooth though.

I never did get a definite answer as far as which one is better for street/mid range between 964 and gt2 cams. Based on my past research, it seems to be split. Many say 964 is for midrange while others say gt2 is for midrange and then you got people saying gt2 is only for 700hp track cars! Even the cam grinders have conflicting opinions.

[pdqcarrera]

Originally Posted by Black_Hat

@pdqcarrera

I have seriously welded and ported heads and intake

http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/767012-forced-deal.html

I was @ 450 whp , I have since installed a modded fuel head for more fuel.Car is tuned but not dyno.

Appreciate the reply & info.
However, I was asking the original poster who noted "Unfortunately I am still on the stock heads".
My heads were ported with expectation to take full advantage of 964 cam. Still CIS though.

[TurboKraft]

Hi all,
The cams we sold to Black_Hat are as radical as we go on a CIS car.
They *do* require small valve pockets -- he sent us the pistons and we machined small valve reliefs in them.
Fun burble at idle, great midrange torque, relentless pull to redline.

They do *not* like a restrictive engine. These work best on engines with ported heads, free-flowing turbos and mufflers, good intercoolers.

[dos531]

Originally Posted by TurboKraft

Hi all,
The cams we sold to Black_Hat are as radical as we go on a CIS car.
They *do* require small valve pockets -- he sent us the pistons and we machined small valve reliefs in them.
Fun burble at idle, great midrange torque, relentless pull to redline.

They do *not* like a restrictive engine. These work best on engines with ported heads, free-flowing turbos and mufflers, good intercoolers.

Well, I have all that except the heads right now, but those will happen later. My Mahle 3.4 pistons have valve reliefs from the factory, are they big enough to clear the lift on those cams?

At this point im leaning towards just throwing some 964 cams at it until I do the full top end. Just seems silly to pull the engine for the clutch and not throw something on the engine at the same time.

[TurboKraft]

Originally Posted by dos531

Well, I have all that except the heads right now, but those will happen later. My Mahle 3.4 pistons have valve reliefs from the factory, are they big enough to clear the lift on those cams?

At this point im leaning towards just throwing some 964 cams at it until I do the full top end. Just seems silly to pull the engine for the clutch and not throw something on the engine at the same time.

Yes, they will clear the Mahle 98mm 3.4L pistons.
964 is a good profile when you have more base CR. But they will never have a lumpy idle, if that's what you want.

[dos531]

Originally Posted by TurboKraft

Yes, they will clear the Mahle 98mm 3.4L pistons.
964 is a good profile when you have more base CR. But they will never have a lumpy idle, if that's what you want.

Are those cams on your site?