Baseline Dyno 3.2SS

[clex2]

Here are my baseline numbers on my 3.2SS single plug, CIS, 964 cams, 98 mm J & E pistons and 95 mm Mahle cylinders bored to 98 mm, 9.5:1 CR, MSD ignition, motor built from a '79 SC. Limter set to 7500 rpm.



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

[lvporschepilot]

Seems low, but you are pretty lean at 6500+. There’s more power to be had once the a/f is corrected.

[Black 993]

Does seem low. I got the same power (a little more, but within the margin of error) on my old SC with 964 cams, 9.5:1 pistons, and early exhaust. CIS, stock displacement. Your AFR's aren't terrible, but they're never really in the sweet spot. They slowly climb from too rich to too lean.

[Sub8]

Holy lean afr batman!!

That needs resolving ASAP IMHO....

[Trackrash]

Now you can work on the tuning. I think you have some more HP potential.

What exhaust and muffler? Heck the right muffler can be 5 - 10 hp. What about the distributor and timing? Air cleaner? And yea the AFM.

There was a thread a while back where someone played with his cam timing on an SC motor and got some gains. Maybe someone can find that link?

[clex2]

Thanks, guys. Yup, next is adjusting the mixture to get the AFR better. Exhaust is SSI in to M&K sports muffler 2 in 1 out and K&N oiled air filter on a stock snorkel airbox with a few additional holes drilled in. Stock single plug distributer. What should I see when all things get corrected?

[mikedsilva]

Originally Posted by clex2

Thanks, guys. Yup, next is adjusting the mixture to get the AFR better. Exhaust is SSI in to M&K sports muffler 2 in 1 out and K&N oiled air filter on a stock snorkel airbox with a few additional holes drilled in. Stock single plug distributer. What should I see when all things get corrected?

On a couple motors here, we found the M&K to be restrictive. Do another run without the muffler to see if this is a potential source of restriction.

Which Muffler? Dynomax, Magnaflow, M&K - Dyno Charts

[Mixed76]

Consider starting the dyno run at 2000 rpm so you can tell more about cam behavior.

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[Black 993]

Have you verified that you're getting full throttle opening when the gas pedal is floored? On old cars, especially ones that have been worked on, it's very common that the linkages need adjustment.

[clex2]

I haven't verified the throttle is opening completely. I will check on it.

[safe]

Originally Posted by Black 993

Does seem low. I got the same power (a little more, but within the margin of error) on my old SC with 964 cams, 9.5:1 pistons, and early exhaust. CIS, stock displacement. Your AFR's aren't terrible, but they're never really in the sweet spot. They slowly climb from too rich to too lean.

Lean from 5500 I would say. But it is cis so it might be hard to correct.

[clex2]

Contemplating Franken CIS or modified WUR/FD. Anyone have any experience with that. Seeing what can be done reasonably before going to ITB/EFI.

[safe]

I looked at Franken CIS before, but I think its a kludge. Would consider it if I wanted to retain the stock/original look on special car.
If not going ITB, I would buy the specific bits from the bitzracing and combine it with a proper EFI system.

[winders]

If going ITB, I would go with AT Power ITBs. They are killer on 3.2 engine. They make big power and have incredible throttle response. I am using those on my hyper 3.6L engine along with a MoTec M130 ECU but they work great with any quality ECU.

[CBA]

Okay hope you don't mind looking at this and I'm not trying to hijack.... thought it would be interesting to see a similar Build 3.2 SS ('83 case) w/ Mahle Pistons & Cylinders 10.0:1(actual 9.8:1) Compression measured, 964 cams, MSD Ignition, 46 PMO's and SSI with 3" custom exhaust from Turbo Hoses. Single plug, 98 octane 6800 RPM's test in 3rd gear. 4th gear test HP 182 & Torque 193

[clex2]

CBA, so you know Hoover. My car was Dynoed at his shop. Correct me if I’m wrong but it appears either my CIS is doing prettty good or your ITB setup needs more tuning? Some say there is like another 30-40 hp to be had going from CIS to ITB/EFI on these 3.2SS? I need to go back and see if there is anything I can do to riches the Mixture on the CIS. I already gave a quarter turn clockwise on the fuel distribution block and I noticed the idle was smoother.

[Mixed76]

Maybe you're both being held back by SSIs.

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[CBA]

Interesting... I'm no expert at all......so anything I say can and will not be held against me I've been told by that CIS and Carbs maybe you can get 15 HP...maybe... but at the end of the day CIS can be tuned pretty darn close to carbs. Carbs are more of the fun factor, sounds a little cooler, looks cooler and maybe a little more responsive. My car was tuned without a dyno and I don't know what the timing was set at... maybe this could make a difference? Yes I know Hoover and would love to go up there and have him tune my car on his dyno just a little bit of a hike for me. The dyno guy I used said my fuel mixture looks really good across the board but their are different adjustments that could be made. My motor has about 2,000 miles on it and I really haven't tried to dial it in but I'm not sure how much more can be made. I consulted with Steve W. when I built this motor with the goal of having something reliable, single plug, and fun and he felt that 215 to 220 HP(crank) would be what I'd get out of it which seems pretty accurate based on these numbers at the wheels. I've also consulted with a handful of other builders who agreed with Steve's #' but also said if I went with more aggressive cams, timing, and dual plug I could see 230-240 HP. Not sure what your goal was when you built yours.

[CBA]

I'd be interested in hearing from some "experts" on the horsepower / torque numbers on how mine looks. My buddy is doing some testing for some new headers. I can't share the company yet but will when given permission. His 1973 911 w/ a 1989 3.2 Stock motor with CIS yesterday w/ custom 1 5/8" ID 13/4" OD headers, 2 in 2 out exhaust and his HP was 192 and torque was @ 172. We meet up today to dyno his car again He had same headers w/ Megaphones and his HP went to 198 w/ Torque @ 178. Tomorrow he is doing European style headers w/ 2 in 2 out exhaust. He will do a 4th test with Stock SSI's and 2 in & 2 out exhaust.

Fun Stuff. All in all I'm happy with what I have... I think

[targa72e]

CBA,
Your numbers indicate problems. You need some tuning or different parts. Your power falls off bad above 5K RPM.
I posted several dyno runs of well tuned stock 3.0, SSI (or headers) with stock cams and CIS in the thread below.

Air fuel ratio

I also show how bad a muffler can be even if you can see straight thru it.

The dyno below shows 3 runs on same day same care with megaphones vs early muffler (loelles) converted to sport (straight pipes out rear, loud) vs early with second outlet on end (davids) . You can see the numbers are about the same but slight change to shape. I tried a lot of mufflers (most sucked) on a stock car and early muffler with second outlet is hard to beat for power.




john