Baseline Dyno 3.2SS

[CBA]

Originally Posted by 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

Thanks John for sharing. Really appreciate and will look into it more. Always learning here.

[Black 993]

CBA you really are down on power. Years ago I had an SC and did a build with 964 cams, 9.5:1 compression pistons, SSI's and early muffler. Stock displacement, stock CIS. Put down an honest 200 at the wheels. You should be doing better than that with more compression, more displacement, and carbs.

[Focker]

CBA, why did you use 964 cams with those pistons? Are those the CIS style pistons or the carb/EFI pistons?

You may have too high of dynamic compression with that little overlap.

[CBA]

Originally Posted by Focker

CBA, why did you use 964 cams with those pistons? Are those the CIS style pistons or the carb/EFI pistons?

You may have too high of dynamic compression with that little overlap.

Bingo. CIS Pistons w/ single plug, heads ported to 38mm, 964 cams, MSD, SSI headers, 3” exhaust( think this is too big) but it sounds so nice. Do you think headers and exhaust could change things up?

Carb/ EFI compression pistons was too high at 10:2 For single plug I was instructed .

[targa72e]

CBA, If you compare the dynos I posted with yours which were all done on the same type of dyno (dyno Jet) you are down on power. If we take the 187HP made with a 3.0 and extrapolate to a 3.2 you would have 198HP. This is with stock CIS and Stock cams. Considering that most 3.2 Carrera motors (which are smaller then your 3.2) on a dynojet make in the area of 220-230HP with stock cams and 230+ with 964 cams you are missing a lot of power. Some dyno examples below

https://www.911chips.com/dyno.html

I would think with carbs and your setup you should be in the 230-240HP at the wheels with a HP peak at 6300-6400 RPM.

You will have to do some investigation to figure out where you are loosing power. Muffler, cam timing, A/F ration and ignition timing is where I would look.

john

[jpnovak]

Originally Posted by 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.

If you look at the torque curve you will see that the carbs are making nearly 20 ft lbs more torque across most of the mid-range power band compared to your CIS. Agree that the peak numbers are nearly the same but I can guarantee that the carbs will feel much stronger accelerating.

Yes, Peak power rpm and torque drop off are steeper than I would expect on both posted graphs.

[fred cook]

Originally Posted by 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.

Franken CIS or maybe even worse! When I built a 3.3SS for my SC, I decided to keep the CIS system but modify the stew out of it! What I wound up with is an early large port air box, hardware from a 1980 system and a reconfigure to be more like the 73 1/2 system. I also did a little trick with the cold start valve. I added a push button switch and wiring so that the CS valve would be opened at wide open throttle. It is also wired to activate when starting a cold engine. I also added an A/F gauge to help with tuning. End result (after lots of tuning time!) is a system that pulls like stink all the way up to 7500 rpms where it hits the ignition interrupt. You probably need to know some more about the engine so here tis: 11:1 Mahle low dome pistons, LN Engineering slip fit cylinders, 964 cams, Carrera twin plug heads, matched ports at the head/intake runner and at the head exhaust and the SSI tubes. I had to open up the ends of the intake runners about 3mm to match the head intakes and I had to flare out the SSI exhaust tubes about the same amount to match the cylinder head exhaust ports. Compression on all cylinders runs either 160 or 161. With the 7th injector (CS Valve) the A/F ratio improves from about 14.5 to about 13.0. The airbox has the little aluminum "spider" that helps to direct fuel to all cylinders. Ignition is handled by an XDi crank fired/twin plug system. I have the initial timing set at 8 degrees and the all in advance is 28 degrees. Being able to set the timing at a lower value reduces the negative work done by the piston, helps the engine to run cooler and allows the engine to run safely on 91 octane pump gas. Here is a picture of the Cold Start Valve actuation switch. I hope this will give you some ideas for your induction system. Don't be afraid to jump in and try some things!