Dyno Results - Rebuilt SC with 9.5 JEs, 964 Cams, SSIs

mca · 11:13 AM

Well, here are the results from today’s dyno day run. This is an 82 SC with 964 cams (advanced timing on cams), 9.5 JE pistons, SSIs and a Dansk sport exhaust. The engine has just over 2500 miles on the clock.

Higher Resolution Image of Dyno Chart

Video of Dyno Run

I asked them not to exceed 6000k RPMs because I was being a wuss. Hopefully some of you can chime in and tell me if you think there was some more power on the table. You can see that the run was stopped at just under 5900k RPMs – hard to tell if the power was dropping off b/c there are a lot of little peaks. Given that this was a dyno day we were not afforded the opportunity to tune the cars.

The best run showed:
Max Power = 157.58
Max Torque = 153.45

I know it is subjective to estimate power at the flywheel, but with 15% loss I am getting 181 HP.

The AFR exhaust clamp fell out after the second run. That is why you see a flat line in the AFR results.

Kevin ran his also and we have the exact same set up except his is an earlier SC with larger intake ports. His max power was 180 (didn’t catch the torque). Very solid number.

Feedback and interpretations are welcome.

Thanks,
Craig

Buckterrier · 12-13-2008, 11:13 AM

I'm certainly no expert at all but isn't 180bhp stock for your engine? I hear ya about the rpm's!! My guy cranked it up to 6,500 rpm the 2nd run. Thought she was going to explode! My peak horsey's hit right at 6,200 @ 205 rwhp after rebuild. Were you expecting more bhp?

mca · 12-13-2008, 11:24 AM

Quote:

Originally Posted by Buckterrier

I'm certainly no expert at all but isn't 180bhp stock for your engine? I hear ya about the rpm's!! My guy cranked it up to 6,500 rpm the 2nd run. Thought she was going to explode! My peak horsey's hit right at 6,200 @ 205 rwhp after rebuild. Were you expecting more bhp?

Yea, I was hoping for somewhere between 180-200 given the mods. I plan on running it again when it is not a dyno day so that I can dial in some better performance and run it up past 6000.

I was also hoping to get dizzy advance numbers - I still haven't checked for proper advance. It is pretty hard to do with the timing gun and my wife's foot on the pedal.

VFR750 · 12-13-2008, 12:22 PM

Your torque was still holding as you reached 5900rpm, so likely you had not reached the peak HP. Jokingly, I'd say "yes" you wimped out. Redline is 6300, and a fresh rebuild should be the same. So tell the guy you run to 6500, and he'll pull to 6300.

It's tough to say for sure, because of dyno-to-dyno variation, but you seem to be low in torque for a 3.0 SC. I saw 165 ft-lbs @ 4250 rpm with stock exhaust. I would have expected 175-180 ft-lbs based on all the comments on the SSI's torque benefit. So your 153 does seem low.

~14:1 AF ratio looks too high, should be 12.7-13.1 for peak power. Might explain some of it, although the penalty is only 3%. See the chart (not sure where I got it from)

84CarreraSC · 12-13-2008, 12:24 PM

It did not sound like it was having any issues to me. I think that your tuning might just be a bit off which would leave HP on the table. You should have just had my attitude and let them run it up to the limiter! Just kidding I completely understood your holding back till she has some more miles on her. How about that GT3 Cup Car; 409 at the wheels......WOW!

don gilbert · don gilbert's Garage

most definitely air fuel ratio is off for peak power, that hp number would dissapoint me, after all your work, (followed you work, i want that configuation myself if i can ever wear my 3.0 out) i think there is way more to be had after tuning, and maybe the motor is still a little tight.

mca · 12-13-2008, 02:43 PM

Quote:

Originally Posted by don gilbert

most definitely air fuel ratio is off for peak power, that hp number would dissapoint me, after all your work, (followed you work, i want that configuation myself if i can ever wear my 3.0 out) i think there is way more to be had after tuning, and maybe the motor is still a little tight.

Yea, it is lower than I wanted. With some mixture and timing adjustments I think that I can get it right. I feel that there is a lot to be had. There is also the possibility that I have a fuel delivery problem - getting a stumble at low RPMs and I have exhausted all possibilities. I put new injectors in b/c my old injectors somehow became clogged while swapping the CIS from my old engine onto my new one. Maybe the fuel filter is clogged too - need to investigate more.

Also, because I am a baby, I want to get some more miles on it before pushing it to the limiter. Next week I will be putting another 1000 miles on it - hopefully I will get back on the dyno in early January.

mca · 12-13-2008, 02:45 PM

Quote:

Originally Posted by VFR750

~14:1 AF ratio looks too high, should be 12.7-13.1 for peak power. Might explain some of it, although the penalty is only 3%.

Thanks for sharing the chart. I looked at some other AFRs on this board and most of them are in the range you suggested. I'll take that 3%!

Jeff Alton · 12-13-2008, 03:16 PM

Do you have a "before" dyno showing the power it made before mods? If not do not worry about the number. All dyno's read differently.....

Cheers

wilke3169 · 12-13-2008, 03:30 PM

Find attached my dyno data from today. 3 runs, Max Power 180.38, Max Torque was 168.59.
Was the first dyno run for my car which was rebuilt, by me, approximately 3 years ago, 25,000 miles ago.
Craig also video taped my run but I haven't seen it yet.

I was pleased with the numbers, almost dead on what I expected. I actually guessed 176 HP before the runs.

Rusty Heap · Rusty Heap's Garage

I'll have to go dig up my dyno chart, Just a smidge more H.P. than yours (grins) but nothing to worry about. You did fine, it's all how fast those revs come up on the street, and I LOVE the 4000-6000 pull on the street with the cams and my SSI headers. Just like coming on the pipe on a 2 stroke ATV...........the cams AND SSI's let it breathe.......you didn't roll off too soon on the RPM so don't sweat it. It starts dropping off soon after that.

mca · 12-13-2008, 04:05 PM

Quote:

Originally Posted by wilke3169

Find attached my dyno data from today. 3 runs, Max Power 180.38, Max Torque was 168.59

Those are great numbers. Your max hp was around 5900k RPMs. Thanks for sharing your chart.

Looking at yours for comparison, it is clear that my hp should be higher at 5900 regardless of when they let off of the throttle. Had you not been there to run yours I would probably have dismissed my low numbers.

Despite my poor showing, I had a great time today. It was a great turn out with a nice variation of cars.

Kevin - is it me or do my readings seem to be all over the place compared to yours? Seems like I am getting some hefty fluctuation.

wilke3169 · 12-13-2008, 04:23 PM

Craig, I really think your issue is just a tuning problem. Not sure I know enough to say your readings are all over the place or why. Seem to be pretty close to mine actually, as far as the fluctuations.
It was a good turn out and a good day.
If the video turned out ok and you can upload it somewhere so I can view it that would be great.

Kevin

mca · 12-13-2008, 04:32 PM

Quote:

Originally Posted by wilke3169

Craig, I really think your issue is just a tuning problem. Not sure I know enough to say your readings are all over the place or why. Seem to be pretty close to mine actually, as far as the fluctuations.
It was a good turn out and a good day.
If the video turned out ok and you can upload it somewhere so I can view it that would be great.

Kevin

Gimme an hour and I will put it together. I'll post it here when I am done.

dfink · 12-13-2008, 04:41 PM

I hate to ask but have you checked to make sure the throttle is opening all the way. Also with 2300 miles on the rebuild should be ready to play. HP is a function of RPM though max torque was 5500. Looks like it was maybe starting to fade on the HP around 5900. Also agree it appears to be very lean. Did you do any changes to fuel supply to counteract the better breathing headers if not that is probably the reason for going lean.

mca · 12-13-2008, 04:50 PM

Here is Kevin's sweet ride on the dyno today!

Kevin's Dyno Video

I love how they can all sound so different too. He has a really nice car.

mca · 12-13-2008, 04:54 PM

Quote:

Originally Posted by dfink

I hate to ask but have you checked to make sure the throttle is opening all the way. Also with 2300 miles on the rebuild should be ready to play. HP is a function of RPM though max torque was 5500. Looks like it was maybe starting to fade on the HP around 5900. Also agree it appears to be very lean. Did you do any changes to fuel supply to counteract the better breathing headers if not that is probably the reason for going lean.

Great question. With the throttle pegged to the floor I still have a slight amount left at the throttle body but I think it isn't enough to make a difference. I read that the accelerator pedal should stop before the stop on the throttle body but I don't know how close they should be. Any insight?

I have not made any changes to fuel supply. Kevin has the same motor with the exception of bigger intakes and I don't think he made any changes. I pretty much follow his lead ... you can see how his turned out. I want mine to run like his!

Scott R · Scott R's Garage

you did better than me, I'm going back in a week with webers instead of CIS or EFI as I've had too many issues with both.

mca · 12-13-2008, 05:11 PM

Quote:

Originally Posted by Scott R

you did better than me, I'm going back in a week with webers instead of CIS or EFI as I've had too many issues with both.

Scott,

Hmmm ... we have very similar builds. After that run did you try tweaking anything?

I'd love to know what happens after you switch. Keep this thread bookmarked somewhere so that you can post a follow-up if you don't mind.

Sending you a PM too.

Thanks,
Craig

Scott R · Scott R's Garage

Quote:

Originally Posted by mca

Scott,

Hmmm ... we have very similar builds. After that run did you try tweaking anything?

I'd love to know what happens after you switch. Keep this thread bookmarked somewhere so that you can post a follow-up if you don't mind.

Sending you a PM too.

Thanks,
Craig

I will, due to our setups I want to see what each of us ends up with. I think in my case the 80's CIS is so restricted for emissions reasons that I just need to drop it. I have enough torque to almost lift the front end in 3rd so something is up, somewhere.