Official 911 Dyno Chart Thread

petevb · 07:06 AM

This is the place to post any and all 3.6 based 911 dyno charts. If we get a good collection, along with spec information on the motors, it could be a great resource for the forum.

The more the better- especially if you've got multiple dynos of the same motor in different states of tune or on different dynos, or motors with known problems.

petevb · 05-10-2007, 08:12 AM

I’ll start with one of mine:
’97 3.6L VRam with mid cams, exhaust and chip- 280.5 hp/ 246.3 tq
3.8 RS hydraulic cams, race springs and titanium retainers
B&B headers, custom flowmaster cross flow muffler
Chip (Rennsport?)
Light flywheel, 915 gearbox
93 Octane pump gas
DynoJet Chassis dyno
Dynoed by Craig 930

Dennis Kalma · Dennis Kalma's Garage

Too bad there wasn't a way to get the data points and get them into Excel or something. It would be useful to have all the data, engine specifications and then be able to graph them to determine differences....

Hmm....I'd be willing to help out....

Dennis

justinp71 · 05-10-2007, 12:54 PM

So that is at the rear wheels?

petevb · 05-10-2007, 02:36 PM

I was thinking the same thing on excel- maybe I edit the original post when we get some more data.

Yes, that's a chassis dyno, so it's rear wheel. My belief is that the drive-line loss for that configuration on a Dynojet is only about 10%, so that works out to about 312 hp at the crank.

petevb · 05-10-2007, 03:47 PM

’95 3.6L VRam with cams, big valves, exhaust and chip- est 329 hp/ 292 tq at the crank

I've been asked not to post the raw dyno numbers, so I've corrected to what I believe is crank HP (based on a number of other cars run on that dyno).

3.8 Supercup Solid Lifter cams cut with 113 degree lobe centers
3.8 RS 51.5mm intake/ 43mm exhaust valves, race springs, lightweight retainers
1.75" headers, Coast mufflers
2 custom Cyntex chips- one for 93 octane, one for 100 octane (hence the 2 dynos)
Light flywheel, 915 gearbox

The image below estimates how this motor comares to my other one. The solid lifter cams and bigger valves help the torque and high RPM power- otherwise the motors are close to identical. There is danger in reading into this, however- I'm comparing data from two different dynos here, and it's going to be off one way or the other...

petevb · 05-11-2007, 07:20 AM

Seems that I'm, perhaps the biggest dyno dork here? Or it's just a touchy subject... I'll post a couple more. Below is a chart from the web of a selection of 3.6 based motors, all dynoed by the same guy. My motor on 93 octane is simply the purple "3.6" line in the middle. That 3.9 is mighty impressive... These are all predicted crank HP, of course.

DW SD · 04:44 PM

Pete,
This is not a chart, but may be of interest:
'93 964 bottom end, '95 993 heads, '95 993 Motronic and stock induction. 993 HEs, 993 Super Sport Cams.

Dyno Dynamics Dyno (RWHP)
Graph File
:2VKY842.025
Description: 71 911 3.6
03/08/2006 A:0.996 X:1.100
Speed Ign. RPM Power Torque Temp Air/Fuel VacBoost
MPH RPM HP FtLb OF Gasoline (Atmos)
50 2629 108.2 216 72.5 13.1 -0.1 inHg
52 2731 115.8 223 72.5 13.1 -0.1 inHg
54 2843 120.9 223 72.5 13.1 -0.1 inHg
56 2952 125.4 223 72.5 13.1 -0.1 inHg
58 3061 133.8 230 72.5 13.1 -0.1 inHg
60 3173 137.5 228 72.5 13.1 -0.1 inHg
62 3281 142.1 227 72.5 13.1 -0.1 inHg
64 3389 145.6 226 72.5 13.1 -0.1 inHg
66 3499 149.0 224 72.5 13.0 -0.1 inHg
68 3603 156.8 229 72.5 13.1 -0.1 inHg
70 3718 167.8 237 72.5 13.0 -0.1 inHg
72 3832 175.0 240 72.5 13.0 -0.1 inHg
74 3944 184.9 246 72.5 13.1 -0.1 inHg
76 4059 189.9 246 72.6 13.0 -0.1 inHg
78 4161 201.2 254 72.5 13.0 -0.1 inHg
80 4275 209.6 258 72.5 13.0 -0.1 inHg
82 4391 221.5 265 72.5 13.0 -0.1 inHg
84 4501 232.6 271 72.5 13.0 -0.1 inHg
86 4609 240.7 274 72.5 12.9 -0.1 inHg
88 4720 243.4 271 72.5 12.9 -0.1 inHg
90 4830 249.3 271 72.5 12.8 -0.1 inHg
92 4935 254.0 270 72.5 12.8 -0.1 inHg
94 5052 257.0 267 72.5 12.9 -0.1 inHg
96 5159 263.1 268 72.5 12.9 -0.1 inHg
98 5261 267.4 267 72.5 12.9 -0.1 inHg
100 5367 267.7 262 72.5 12.9 -0.1 inHg
102 5475 267.6 257 72.6 12.8 -0.1 inHg
104 5568 260.6 246 72.6 12.8 -0.1 inHg
106 5672 266.8 247 72.6 12.8 -0.1 inHg
108 5776 266.0 242 72.6 12.8 -0.1 inHg
110 5879 272.8 244 72.5 12.8 -0.1 inHg
112 5981 271.6 239 72.6 12.8 -0.1 inHg
114 6094 270.4 233 72.5 12.7 -0.1 inHg
116 6189 266.9 227 72.5 12.6 -0.1 inHg

petevb · 05-17-2007, 06:13 PM

So your dyno is an interesting one; it actually got me thinking about starting this thread. There is another guy who posed on this board, ted, with a very similar motor spec who tested on the same type of dyno as you did. Specs on the two motors, near as I can tell:

So very nearly the same. Same intake, heads, valves, similar cam, etc. So on paper I'd expect them to make similar power. But when you look at the two dynos:

You've got way more torque early, then fall off fast, and ted comes on late and keeps flowing forever, so he ends up with significantly more peak power.

At first I though the fall off in your motor was caused by a broken flapper, but the fact that you have way more power early, for no obvious reason, makes me think something else is probably going on. My best guess now is cams- maybe just the timing or valve adjustment? Maybe someone else recognizes these signs? I have an engine simulation program that I was going to plug this into to try and re-create the issue, but I haven't had a chance yet. I'll let you know when I do...

-Pete

DW SD · 05-17-2007, 08:52 PM

Pete,
I know the Super Sports are definitely a size down from the Super Cups. Here are my cam specs.

I thought my cams were bigger than stock, but the engine definitely seems to peter out early. It pulls hard from early on though.

Doug

petevb · 05-18-2007, 12:54 PM

So those cams are actually really close to the supercups. Same lift, 2 degree less intake duration, but 2 degrees more exhaust duration... I dug up my engine sim and plugged in the numbers- the two different cams performed nearly identically. So I played around a little and came up with some interesting results.

This is done on a simple engine sim, not the greatest thing in the world, so it's not exactly accurate. It have found it very accurate for predicting trends, though. The specs you posted are what the cam was supposed to be set at, right? But how sure are you what it's actually set at?

Check this out:

Above is how the engine sim models a 993 motor with SS cams, your valve sizes, exhaust, etc. The only difference between the two graphs is where the cam advance sits. The graphed results are predicted power at the crank, so it's not far off if you correct your WHP figures. Notice how this graph looks very similar to the one I posted above of your motor vs teds? Hmmm...

Could be wrong, of course, but if your flapper valve is good, I'd certainly take another look at how that cam is set next. Seems suspiciously coincidental, but...

DW SD · 05-18-2007, 01:58 PM

Pete,
Interesting!!

I trust the builder, but did not look over his shoulder when degreeing the cams. An error is one thing, but I can't imagine he'd have set them all the same amount advanced or retarded.

How do the lobe centers compare between the two cams?

I probably should dyno again to compare results.

Steve Wong sent me another chip recently, so before and after may be insightful.

I'd like to figure out a good way to test the flapper valve. My redline is set for 6700, so it doesn't pull beyond that, not that it would have mattered, given the fall-off around 6200 rpm.

Wonder if my results might be translated to crank HP, where Ted's were RWHP. If you correlated that data, would it indicate a problem?

An error could just as easily been on the dyno operator side as the cam installation. I'm sure he told me they were rear wheel, but of course, as a customer, that is what you want to hear.

Doug

petevb · 05-18-2007, 03:03 PM

The lobe centers of the two cams are just a degree off. According to the program the two cams are less than 5 hp off for most of the pull.

Regarding the cam timing thing, I'm not sure- I have no idea at what point you get metal to metal contact with the cam degreed that far off, or how they could get that way, etc.

You're making good torque, so you're looking for something that is cutting the airflow at higher rpm. That can only be the intake, cams or the exhaust. You could try testing at the dyno one at a time- dyno it without the exhaust, with different headers, with the flapper connected vs disconnected, etc. Process of elimination...

The 993 headers- are there still cats that could be clogged or something? A very small diameter header or very restrictive muffler would look similar to this as well.

I don't believe that it's a dyno operator thing. All they can really do with correction is shift the curve up or down, but nothing changes the shape of the curve, and nothing he could do would change your seat of the pants feel that the engine falls off around 6200...

DW SD · 05-18-2007, 03:13 PM

The 993 exhaust opens into a dual inlet / dual outlet exhaust w/ no cats.

The muffler would be closer to running open exhaust than dual cats and dual mufflers in the stock configuration (I would think).

Doug

DW SD · 05-18-2007, 03:15 PM

Not that you can tell by looking at the outside, but here's the exhaust:

iangray100 · 05-19-2007, 04:12 AM

One for your record ...

UK 1992 964 3.6 STD C2 Tiptronic
Taken today 19/May/2007 1200miles after a full engine rebuild ..see thread
964 3.6 full engine rebuild ...over in the UK
Full STD cat and exhaust
RON 95
Cool sunny day

Porsche spec Factory:
250HP(183.87KW)
228LBS/FT (309.12Nm) torque

My readings:
251BHP (184.61KW)
229LBS/FT (310.48Nm)torque