Hampton

I am not sure what to think about this: Local car club held dyno today. Conditions perfect, 55f deg,clear, high pressure front just moved through. Car is a '93 RS America,#139

Never previously dyno. The dyno is a recently installed and calibrated "Dynojet Research" or something.Three runs:
DynoRun 001: MaxRWHP 252.8 Torque 233.4
002: MaxRWHP 253.8 Torque 234.7
003: MaxRWHP 251.6 Torque 232.3

Curves very consistent. Max Torque at 4600rpm,max RWHP at 6350rpm.I ran to almost 6700 RPM

Most interesting: I ran right after friend w/993 C2 with B&B exhaust,cat bypass,filter mods:his max RWHP was 250.5,torque 230.7.

I know this is just a machine and a number, etc., but I was a little surprised. The car has always pulled great at DE's. Needless to say, I am sweet on my car today!

Adrian

Dear Hampton,
The reason you did not hit the rev limiter is because it has been removed. This is something everyone has to be careful of when installing these aftermarket chips. I have seen people say, "and now it revs to 7200 easily". Yep it will, pity it was not designed to do this.
Ciao,
Adrian
911C4

Kevin

Hampton;

Those are some strong numbers. With a 15% hp loss through your drivetrain, you are putting out over 300HP, not bad. How many miles do you have on the car? What octane fuel were you running?

Adrian;

I have noticed your recent 1000plus post this past week, Congrats, its time for you to and a new model to your stable 993, 993TT or?, so you can start another book. By the way, Hamptons rev limiter hasn't been removed but re-adjusted---probably to 7200rpm's. His RSA can live there on brief occations, however he is stretching the limit of his rod bolts.

Jeff Curtis

Hampton, the reason why your figures were pretty much equal to the 993 is a fairly simple explanation. The 993 motor, with 35 more HP, is basically a more efficient 3.6 - not much was done to the internals for the 993 except for a better exhaust/induction setup.

Now, your buddy had exhaust modifications - it has been discussed on this board many times that the 993 setup is far more efficient than the 964 exhaust setup...basically stating that when a 964 owner modifies -or- upgrades their exhaust, the HP gain is significantly more than gains for the same mod done on a 993, same with intake mods...better HP gains. As for software, well, that's a simple one...Porsche engineered better software, especially with the introduction of OBD-II in 1997.

If it's as simple as installing a chip for more HP in a 964, then the same for the 993...so where did they get the HP increase for the 993? Better exhaust, better intake and probably a "massaged" DME.

So, I would venture to say that almost any modification you make to gain HP in a 993 isn't as much "bang for your buck" when compared to the same mod on a 964.

In working on my 964 and helping friends with theirs I have figured out that while the 964 is a good strong runner, it has it's inefficiencies...I truly believe the 993 is just more efficient, therefore creating more HP out of the factory.

I also concur with Kevin on the rev limiter issue, when I had my chip burned, the rev limiter was raised to 7K, by my choice...most manufacturers like Weltmeister and Autothority raise it to 7200. Besides, who would be that idiotic to actually remove the rev-limiter?

I know, someone will come back on here and criticize what I've said, that's okay, but this "theory" I have can be backed up with documented info.

Kevin

The 993 got a MAF sensor which was a improvement over the barn door air sensor. And in 96 Porsche introduced the VRAM. More HP and more torque.

Hampton

Kevin, Dyno run was done on the fuel that I always use: 93 from a local station. Nothing special.

I checked the info from the chip, and as Jeff and others state, the rev. limiter supposedly re-set at higher level. My original comments were just my observation that I stopped early before encountering any fuel shutoff. HP and torque curves demonstrate that no need to run RPMs beyond 6700 anyway. Beyond that, torque is on the way down.

I was really hesitant to post these dyno figures, as they can be misleading. I was just surprised somewhat at the result. I now believe that if one has the opportunity to dyno their car, and if interested at all in performance, they should do it.

jonfkaminsky

You guys have the same pulling gear transmission ratio as well? If not 1.0, you'll have to back that out of the numbers as well. I'm pretty sure the RSA is not 1.0.

jon

Hampton

Jon,
The 993 who ran right before me is a 6-speed and he ran in 4th gear, as I did in my 5-speed RSA. In fact, all drivers were instructed to use 4th gear.
I could send a copy of the dyno pulls (993 vs 964)which were graphed together for comparison purposes. I scanned them as a jpeg.

Kevin

Hampton;

If you could email me the dyno runs. kmatwichuk@att.net Thanks

Hampton

Kevin,
Two attachments headed your way.

George 911-V8

HAMPTON: Great job sounds like your making some good power for a stock motor. I have seen THOM's dyno numbers on his modified 3.6 and yours. You seem to make about 25hp more from a stock motor, as his has some hot parts in it. The dyno don't lie, it just tells the truth. BTW how does your 964 do against the 993?

SWAMP MONSTER

jonfkaminsky

Hampton-
The point is to normalize the data to the transmission ratios you guys ran with. Different Porsches have different transmission ratios for even the same gear. Some Porsches (pre-964) had a 1.0 ratio in 4th gear, so no correction is needed. Stock 964's pulling in 4th gear have a 1.086 ratio which will overstate all results from a dyno. Just divide your HP value by 1.086 to arrive at the correct figure at the wheels. Then divide by 0.85 to get the flywheel value (assuming 15% loss). Then check the tran ratio for 4th gear in the 993 and perform similar calculations. Then you can compare apples to apples.

Your corrected HP value at the wheels would be more like 233 HP, which assuming 15% loss would translate to about 273 HP at the flywheel. Still nothing to sneeze at.

Jon

Jim Michaels

Thanks for bringing that up, Jon. I've been puzzled by Hampton's figures because I also have an early RSA (#146) with almost the same mods as his, but had estimated the gain in hp and tq to be no greater than 10%; 275 flywheel hp max. I'd be happy with that. I'd be interested to see what the 993 figures do with the drive ratio correction. With 290+ true hp I should be able to pass that stock 993 that I close up on at VIR before entering the front straight. Instead, he extends his lead down the front straight by 5 or 6 car lengths.

Hampton

Jon,
OK, here are the gear ratios for the RS/964 and the 993, so that the Dyno figures can be equalized by taking gear ratios into consideration. Info from Up-Fixin der Porsche Vol.X:

RSA 4th Gear: 1.086
253.8 rwhp indicated / 1.086 = 233.7

993 4th Gear: 1.12
250.5 rwhp indicated / 1.12 = 223.7

Using your corrections, the 6-speed 993 in 4th was aided by the lower gearing relative to the RSA in 4th of 5 gears. The corrections made the RSA/964 engine appear stronger, if this is correct.

Final Variable, and is this important: The differences in the final gear ratio. How would you enter this into the equation: RSA final gear/rack and pinion ratio listed as 3.33, 993 final gear ratio listed as 3.44

jfkaminsky

Hampton-
regarding the final gear....the RPM of the engine is reduced by the transmission gear that you are pulling in. You normalized that correctly. The output of the transmission, would then be further reduced by the final gear. In the case of the RSA, the output shaft of the transmission rotates 3.33 times for every one rotation of the drive shafts, for the 993, 3.44 times. And lower gears are torque multipliers, so all things being equal, the 993 would show more torque at the rear wheels than the 964 based only on the final gears. I would say that the 993 measured value at the wheels sitting on the dyno are helped by the final gearing, by a factor of 3.2%

I don't know what to do with this however. The dyno may have some algorithum to correct for this, or it may even assume some final gear ratio. But I do know that a stouter final gear will show better torque. You could get even more **** about this and figure out losses/gains due to tire differences. I think a dyno is best used in measuring performance on the same vehicle..not between vehicles unless they are identical in every way. I hope that whatever I said is helpful to you. :-)