Cam recommendation for 3.4 EFI

[tailwind22]

Considering a cam change for my 3.4 twin plug efi motor. Currently has SC+ cams. Looking for strong low end response and would sacrifice top end as it will not be tracked. Will be going to a GT35R turbo to get things spooling sooner. Suggestions for a grind profile? Would especially like to hear from Chris Carroll. Thanks.

[Spenny_b]

Hi, I'm running (...or will be running) 964 N/A cams in my 965 EFI project, also 3.4 with twin plugs. Like you, it's not a track car so I decided against GT2 cams, from what I read, they're just a little too hairy for what I wanted. I'm working with Chris @TurboKraft too, I know he also has his design of profile and if I knew 3yrs ago that the project would be this long, I'd have bought these, but at the time a pal of mine happened to be selling a very nice pair

The first few pages of my thread (below) has commentary from Chris that you may find useful

S

ETA my signature....original post was from phone

[turbobrat930]

Subscribing!!!

[kenikh]

What's your compression ratio?

[tailwind22]

Originally Posted by kenikh

what's your compression ratio?

7.5:1

[jpilcher]

I went with Dougherty DC13 cams. I recently finished my rebuild and conversion to EFI. I am also running a Garret GSX 61 Ball Bearing Turbo. The DC13 cams give you the best of both worlds. SC low end grunt and 964 top end. Spool is almost instantaneous, and the car pulls all the way to red line.
I would highly recommend them.

[Pat RUFBTR]

I think of installing cams 993SS, they are one of apparently better compromises for our engines 3.4L and even 3.5L. Dougherty can supply them, I have a friend who was able to order it to him in 2013.

[kenikh]

Originally Posted by Pat RUFBTR

I think of installing cams 993SS, they are one of apparently better compromises for our engines 3.4L and even 3.5L. Dougherty can supply them, I have a friend who was able to order it to him in 2013.

I just had a long conversation with John Dougherty about 993SS cams in a 3.4L 930. Per his recommendation, 993SS are generally not recommended for turbo engines under 9.0:1 (no typo) static CR at book cam timing. He said that if you advance the cams 4 degrees, 8.5:1 will work. Although he's never tried it, he expects that it might be a little laggy, especially if you're running a slower spooling turbo.

Once you're on boost, it all changes, of course.

Based on my calcs, at-idle static CR (on book timed) 993SS cams is even lower than for GT2 cams, meaning you can expect lazy performance off idle. Advancing the timing will net you a little more dynamic compression at idle, but you still shouldn't expect anything better than somewhere between 964 and GT2 performance off the line.

The OP stated he wants more off the line grunt at the expense of top end power. 993SS cams are not the solution for his problem. From his initial post, it sounds like he is running DC15 cams, which although nice, will give up a little off idle grunt compared to an SC cam.

In reality, the OP is probably best off emailing with John Dougherty to get a custom ground cam - ideally something with near stock overlap to maximize off-idle compression, with a little more lift dialed in to allow a little more top end power than the stock cams. A DC 10/12/13 may be a good option in this pursuit.

FWIW, my CIS 8.5:1 CR, 3.4L motor is now coming together with 993SS cams, K27-7006, 40I/38E ports, knock control and twin plugs. Knock control means I'll be able to run a sharper advance curve which should mitigate some of the off idle laziness. Cams will be timed w/ 4 degrees of advance. I'd of course be best served with fast spooling ball bearing turbo, but budget isn't accommodating right now. I'll let you guys know what they are like once I do.

[tailwind22]

Originally Posted by kenikh

I just had a long conversation with John Dougherty about 993SS cams in a 3.4L 930. Per his recommendation, 993SS are generally not recommended for turbo engines under 9.0:1 (no typo) static CR at book cam timing. He said that if you advance the cams 4 degrees, 8.5:1 will work. Although he's never tried it, he expects that it might be a little laggy, especially if you're running a slower spooling turbo.

Once you're on boost, it all changes, of course.

Based on my calcs, at-idle static CR (on book timed) 993SS cams is even lower than for GT2 cams, meaning you can expect lazy performance off idle. Advancing the timing will net you a little more dynamic compression at idle, but you still shouldn't expect anything better than somewhere between 964 and GT2 performance off the line.

The OP stated he wants more off the line grunt at the expense of top end power. 993SS cams are not the solution for his problem. From his initial post, it sounds like he is running DC15 cams, which although nice, will give up a little off idle grunt compared to an SC cam.

In reality, the OP is probably best off emailing with John Dougherty to get a custom ground cam - ideally something with near stock overlap to maximize off-idle compression, with a little more lift dialed in to allow a little more top end power than the stock cams. A DC 10/12/13 may be a good option in this pursuit.

FWIW, my CIS 8.5:1 CR, 3.4L motor is now coming together with 993SS cams, K27-7006, 40I/38E ports, knock control and twin plugs. Knock control means I'll be able to run a sharper advance curve which should mitigate some of the off idle laziness. Cams will be timed w/ 4 degrees of advance. I'd of course be best served with fast spooling ball bearing turbo, but budget isn't accommodating right now. I'll let you guys know what they are like once I do.

Thanks, very informative.

[TurboKraft]

Hi,

If ever you need an answer more quickly, PM me and I'll get a popup email notice. 8-)

You have EFI, so you're not limited to little bitty CIS-friendly cams.
You already have SC cams, going to a DC13 would hardly be a big step up.
964 -- great all-around, but there's room to go, especially if you want more torque and are willing to forego a little peak power to get that punch.

Look at my recent post about swapping out factory SC cams for some bigger TK EFI-T camshafts in a 7.5:1 3.4L EFI 930 with a GT35R : http://forums.pelicanparts.com/8269836-post179.html
Huge torque gain by 3,000rpm, power until 6,000rpm with a flat manifold.
They would be a drop in replacement on your engine.

FWIW, we've done 600rwhp on a 3.5L stroker with these same cams, flat 930 manifold.
Fun even with CIS injection -- used in Black_Hat's C2T: http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/767012-forced-deal.html

And if you want the all-out-best-of ground camshafts, TurboKraft has partnered with Edelweiss Motorsport and offers their camshafts. Dirk's profiles include all the latest tech in the camshaft's lobe design for optimal performance and durability. Prices are comparable to new factory Motorsport camshafts, and equal in quality.

[kenikh]

^ Dirk is a bad ass.

[philip j]

I run these cams, and do not find them laggy at all. Lots of wheel spin in 1st/2nd gear.. Philip

[tailwind22]

Thanks Chris, I will be contacting you.

[kenikh]

Originally Posted by philip j

I run these cams, and do not find them laggy at all. Lots of wheel spin in 1st/2nd gear.. Philip

This is why:

87 930 GHL/Rarlyl8 dual/Garretson/GT3582R/1 Bar/Wevo shift, mounts/Meth inj/LC-1/Custom Fuchs/Carrera intake manifold/Xtreme Carrera heads P&P/3.4/DR 993SS cams/ Mahl/Carrello/JE/Niresist/ARP/twin plug coil packs/8:1/KEP stage 2/twin tials/close 2,3,4th. SDS EFI tuning always in progress. 500+ HP, BTSOMP Dyno

[TurboKraft]

Originally Posted by kenikh

^ Dirk is a bad ass.

Indeed!

[Pat RUFBTR]

Originally Posted by kenikh

I just had a long conversation with John Dougherty about 993SS cams in a 3.4L 930. Per his recommendation, 993SS are generally not recommended for turbo engines under 9.0:1 (no typo) static CR at book cam timing. He said that if you advance the cams 4 degrees, 8.5:1 will work. Although he's never tried it, he expects that it might be a little laggy, especially if you're running a slower spooling turbo.

Once you're on boost, it all changes, of course.

Based on my calcs, at-idle static CR (on book timed) 993SS cams is even lower than for GT2 cams, meaning you can expect lazy performance off idle. Advancing the timing will net you a little more dynamic compression at idle, but you still shouldn't expect anything better than somewhere between 964 and GT2 performance off the line.

The OP stated he wants more off the line grunt at the expense of top end power. 993SS cams are not the solution for his problem. From his initial post, it sounds like he is running DC15 cams, which although nice, will give up a little off idle grunt compared to an SC cam.

In reality, the OP is probably best off emailing with John Dougherty to get a custom ground cam - ideally something with near stock overlap to maximize off-idle compression, with a little more lift dialed in to allow a little more top end power than the stock cams. A DC 10/12/13 may be a good option in this pursuit.

FWIW, my CIS 8.5:1 CR, 3.4L motor is now coming together with 993SS cams, K27-7006, 40I/38E ports, knock control and twin plugs. Knock control means I'll be able to run a sharper advance curve which should mitigate some of the off idle laziness. Cams will be timed w/ 4 degrees of advance. I'd of course be best served with fast spooling ball bearing turbo, but budget isn't accommodating right now. I'll let you guys know what they are like once I do.

Hello,
It is strange, in a conversation with my friend, Dougherty told him that of the good about acc 993ss. Compared with those of Gt2/ Gt2evo they are better in the bottom and at the middle regime and then our power is not situated in 7500tr / mn.
I would be very curious to have more precision about acc Edelweiss Motorsport, I found nothing on their Web site.