Oh no, another cam recommendation thread!: street-driven mild 3.6 EFI/ITB

[msmall215]

I've skimmed through a bevy of threads and there's a lot out there around 2.7-3.4 motors, but not as much around 3.6s that I could find. Rebuilding a '92 3.6 into a mild hot rod motor with stock P/C, leaving heads alone, but with ITBs/EFI. Planning to modify factory manifolds into a GT3 style plenum with Jenveys, similar to the Rothsport setup. Car will only see 2-3 DE track days a year, so 95% street driven. Wide power band and good low-mid range torque is paramount.

Anybody have experience/thoughts/recommendations? 20/21? DC21? 993SS?

Thanks!
-Mike

[spyerx]

My 964 engine was rebuilt to stock specs however it has stock induction and plenum, but has 993ss cams, rothsport headers, and tune to support it. The car pulls very nice.

I suspect you’ll get some gain from the induction but to make real power head work is needed.

[Nux]

Originally Posted by msmall215

I've skimmed through a bevy of threads and there's a lot out there around 2.7-3.4 motors, but not as much around 3.6s that I could find. Rebuilding a '92 3.6 into a mild hot rod motor with stock P/C, leaving heads alone, but with ITBs/EFI. Planning to modify factory manifolds into a GT3 style plenum with Jenveys, similar to the Rothsport setup. Car will only see 2-3 DE track days a year, so 95% street driven. Wide power band and good low-mid range torque is paramount.

Anybody have experience/thoughts/recommendations? 20/21? DC21? 993SS?

Thanks!
-Mike

Talk to William Knight. He has a pretty good cam for your application. You would get a better result with other pistons, but slippery slope......

[msmall215]

Originally Posted by spyerx

My 964 engine was rebuilt to stock specs however it has stock induction and plenum, but has 993ss cams, rothsport headers, and tune to support it. The car pulls very nice.

I suspect you’ll get some gain from the induction but to make real power head work is needed.

Originally Posted by Nux

Talk to William Knight. He has a pretty good cam for your application. You would get a better result with other pistons, but slippery slope......

Good call, will send him an email. And yes, very slippery slope. I thought about going 3.8, headwork, etc, but for mostly street, I think it'll be more than enough. Plus, I'll be keeping the 915 with the addition of CMS billet side plate and retainer along with a refresh, so trying to keep the numbers more reasonable.

[targa72e]

You might look over at the 964 forum on rennlist, lots of 3.6 and larger builds their. By keeping stock P&C you are limiting cam selection to stock type cams. These work best with stock type intake. To take advantage of ITB you need different pistons to support more aggressive cams. This also requires upgraded rods to take advantage of more RPM that your cams and intake support.

john

[jpnovak]

just a data point. 993SS cams, otherwise stock internals, stock plastic intake, B&B headers, 997 muffler, Steve Wong chip on Motronic.

267 to wheels on the dyno. I expect you will get more with ITBs since the system is intake limited. However, you can't really add more rpm and cam without work on the bottom end to support.

My $0.02.

[Nux]

Originally Posted by msmall215

I've skimmed through a bevy of threads and there's a lot out there around 2.7-3.4 motors, but not as much around 3.6s that I could find. Rebuilding a '92 3.6 into a mild hot rod motor with stock P/C, leaving heads alone, but with ITBs/EFI. Planning to modify factory manifolds into a GT3 style plenum with Jenveys, similar to the Rothsport setup. Car will only see 2-3 DE track days a year, so 95% street driven. Wide power band and good low-mid range torque is paramount.

Anybody have experience/thoughts/recommendations? 20/21? DC21? 993SS?

Thanks!
-Mike

If you have not allready bought the Jenveys - shoot me an email or pm. Might have something interesting for you

[plexiform]

I modified a 92 964 3.6L with Rasant Product ITBs and GT3 plenum but left the internals stock. Switched to MoTec engine management. BBE exhaust with equal length headers and kept heat. End result is slightly over 300RWHP with 260 ft lbs torque. The car is tons of fun to drive. It is a responsibly upgraded engine that makes for a great street car.

Here is a link: www.rasantproducts.com

[winders]

Andrew at Rasant is great to deal with. I bought my MoTec M130 ECU, custom wiring harness, fuel injectors, WeaponX coil on plug ignition system, and pulley for my new race engine from William Knight who sourced them from Rasant.

P.S. Are you sure that is not crank horsepower? 300 RWHP with a G50 is about 350 HP at the crank. You can't get there with stock '92 internals.

[plexiform]

Originally Posted by winders

Andrew at Rasant is great to deal with. I bought my MoTec M130 ECU, custom wiring harness, fuel injectors, WeaponX coil on plug ignition system, and pulley for my new race engine from William Knight who sourced them from Rasant.

P.S. Are you sure that is not crank horsepower? 300 RWHP with a G50 is about 350 HP at the crank. You can't get there with stock '92 internals.

Yes, that is confirmed 300 WHP. Feel free to discuss it with Andrew at Rasant as he is the one who dyno'd it. Torque is ~260 ft lb.

[K24madness]

With ITB’syou can get pretty aggressive with overlap. DC21 is a great safe choice! Slightly more aggressive than SS/RS cams. In your shoes I’d do the DC24’s though. Much better match for ITB’s & GT3 intake. Those would wind out REALLY nice!

[msmall215]

Originally Posted by jpnovak

just a data point. 993SS cams, otherwise stock internals, stock plastic intake, B&B headers, 997 muffler, Steve Wong chip on Motronic.

267 to wheels on the dyno. I expect you will get more with ITBs since the system is intake limited. However, you can't really add more rpm and cam without work on the bottom end to support.

My $0.02.

Somewhere around there would be optimal...993SS is probably top of the list for me at the moment.

Originally Posted by Nux

If you have not allready bought the Jenveys - shoot me an email or pm. Might have something interesting for you

Sent you a PM!

Originally Posted by plexiform

I modified a 92 964 3.6L with Rasant Product ITBs and GT3 plenum but left the internals stock. Switched to MoTec engine management. BBE exhaust with equal length headers and kept heat. End result is slightly over 300RWHP with 260 ft lbs torque. The car is tons of fun to drive. It is a responsibly upgraded engine that makes for a great street car.

Here is a link: www.rasantproducts.com

Originally Posted by winders

Andrew at Rasant is great to deal with. I bought my MoTec M130 ECU, custom wiring harness, fuel injectors, WeaponX coil on plug ignition system, and pulley for my new race engine from William Knight who sourced them from Rasant.

P.S. Are you sure that is not crank horsepower? 300 RWHP with a G50 is about 350 HP at the crank. You can't get there with stock '92 internals.

I have Andrew's kit on my 3.0 currently coupled with Al's Triumph ITBs, great system.

Originally Posted by K24madness

With ITB’syou can get pretty aggressive with overlap. DC21 is a great safe choice! Slightly more aggressive than SS/RS cams. In your shoes I’d do the DC24’s though. Much better match for ITB’s & GT3 intake. Those would wind out REALLY nice!

Another great option to consider, thanks!

[winders]

Originally Posted by plexiform

Yes, that is confirmed 300 WHP. Feel free to discuss it with Andrew at Rasant as he is the one who dyno'd it. Torque is ~260 ft lb.

With a '92 3.6L, you can't gain 90 HP at the wheels with a MoTec ECU, headers, and ITBs. I wish it were that easy....

[clutch-monkey]

300whp on stock internals LOL
american horsepower strikes again

[plexiform]

Originally Posted by winders

With a '92 3.6L, you can't gain 90 HP at the wheels with a MoTec ECU, headers, and ITBs. I wish it were that easy....

So then my dyno is incorrect? The people working on this car seemed to know what they were doing and I do not think they would give me bad information. I'm by no means an engine expert so if you have some knowledge to share, I'm all ears. FWIW the car feels very good and accelerates very hard compared to before.

[winders]

I don't know what to tell you. All I know is there is no way a stock long block '92 964 engine is going to have 350HP at the crank just by changing ECU, headers, and intake.

I am sure those numbers are correct for that dyno. But that doesn't mean those match real world numbers. It will be interesting to see what my race engine dynos at when Andrew tunes it on that same type of dyno....maybe even the exact same dyno.

[winders]

Well, there is something else to consider. The Dynapack with a Transmission Correction Factor (TCF) of 1.000 (no correction) will be somewhere in between a roller chassis dyno and an engine flywheel dyno.

Another point to consider is what transmission was used and what the actual gear ratio and final drive ratio was used as the Dynapack measures torque at the wheel which must be reduced based on the gear ratio and final drive ratio. HP is calculated from that torque so getting proper torque and HP numbers can only happen if the ratio listed on the chart is correct.

Regardless, let's say the TCF should be 1.09. That is still 328 HP at the crank. That is 81 HP over the claimed stock 247 HP at the crank. Still not really possible.....

[plexiform]

Originally Posted by winders

Well, there is something else to consider. The Dynapack with a Transmission Correction Factor (TCF) of 1.000 (no correction) will be somewhere in between a roller chassis dyno and an engine flywheel dyno.

Another point to consider is what transmission was used and what the actual gear ratio and final drive ratio was used as the Dynapack measures torque at the wheel which must be reduced based on the gear ratio and final drive ratio. HP is calculated from that torque so getting proper torque and HP numbers can only happen if the ratio listed on the chart is correct.

Regardless, let's say the TCF should be 1.09. That is still 328 HP at the crank. That is 81 HP over the claimed stock 247 HP at the crank. Still not really possible.....

I'm curious to see what your engine does on the same dyno. I only mentioned the dyno numbers because I assumed the OP would be interested in hearing about it. While HP/TQ values are cool to talk about, what is more important to me is how the car actually drives. When I got behind the wheel and really pushed the car for the first time, those numbers seemed believable to me. This car is not as quick as my 996t but its pretty darn quick. BTW my car has a 915 trans. Here's a video of it just to to add a visual. No technical info in the video.

https://www.youtube.com/watch?v=2cmpmZmUPtE

[safe]

I'm at 282 whp, stock internals except cams and a slight porting. Also stock intake minus the vane airflow sensor.

[msmall215]

Originally Posted by safe

I'm at 282 whp, stock internals except cams and a slight porting. Also stock intake minus the vane airflow sensor.

Magnus, what cams are you using?