[flatsix]

I got my 968 dynoed on 10/6 at our local porsche club tech session and I am pleased with the results, best pull was 2nd run, 218hp/198 torque, and wanted to share my experience with everybody and see what you guys thought. It was a little scary having them rev my car that high and then suddenly lift of the throttle, but everything was fine and no damage. I'll post pictures when I get them from the guy with the camera( of course I forgot my camera). I'm no expert so any feed back and analysis of the results would be cool.



The dyno was a mustang dynamometer and it was a warm day in the mid 80's, med. humidity. I have the Promax 7100a chip with a K&N air filter and the air box mod. They did 4 runs and it sounded great to hear the car rev. They took it to about 6800rpm or where they felt that was about all the engine would pull and start to drop off. It seemed to pull to 6500-6800 and that was it so having the extra rpm's with the chip I don't think helped with horse power which I'm a little disapointed about, I thought it would make horsepower up to 7100 but 6800 was about the max. They said the car felt strong and the air fuel mix was really good but I'm not familliar with those ratios.



I was the only 968 with all the rest being 911's and 1 Cayenne turbo. A 2003 911 Carrera pulled 250hp, a 89 911 pulled 200hp and squirted some oil in the process, a 911 turbo 350's hp not to redline, and I forget what the Cayenne did but it was the highest hp, but they took it to redline.

It was a fun day and alot of nice 911's to check out.



So let me know what you guys think.

por010.pdf Size: 122.78 KB  Downloads: 80

Bill

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[flash]

the numbers a pretty good, though the real thing is the shape of the curve, and not the numbers, as there are just too many variables to ever consider comparing one set of runs to another



yes, the 7100 chip does fall off early, much as the stock chip does - the peak is higher than the stock chip, but there is no headroom afterward - that was one of my issues with it - fine for a bit more street fun, but a bit lacking as a performer - it is currently in 4th as rankings of performance go



if you are looking for more you really need to go to the rs barn chip - it also offers a trade in policy against future upgrades in software level to match other mods, which seems to be inevitable with this car as owners find more and more fun with each mod

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[JWahlsten]

I've not done any tuning on 968s, but two things jump out at me immediately.



First, the AFR starts off on the lean side then goes toward 12.5 where we try to run the turbo cars. Is this normal?



Next, what causes the torque spike at 4300 rpms? Is that the resonance intake we discuss so often since the variocam kicks at 5500 rpm.



I like the big fat area under the curve. Nice and flat.

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[PorscheDude]

[quote name='JWahlsten' post='42391' date='Oct 15 2007, 10:43 PM']Next, what causes the torque spike at 4300 rpms? Is that the resonance intake we discuss so often since the variocam kicks at 5500 rpm.[/quote]



Yes, that is correct.

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[flatsix]

Thanks flash I'll check into the rs barn chip, I would like to get some more power without getting to heavy into mods.

I loaded some pictures of my car on the dyno if anybody is interested.

   

   

   

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[ds968]

I have the Speed6 Racer X chip, which in some 968s has shown gains up to 7100 rpm, but in my car the

the curve dropped like a bag of sand right at 6600.



mine was 212 hp and 202 ft/lbs rwp , before the airbox mod.



but then again, one dyno day cannot be compared to any other dyno day...

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[94SilverCab]

I concur that the horsepower drops off at 6,700 on mine (RS Barn stage 1). What I do gain with the RS Barn chip is stronger horsepower and torque throughout the entire range.



So what's the point of upping the rev limit if you don't gain anything?...if you get to 6,600 it seems reasonable that you should be shifting unless you have an overwhelming reason not to...



Just my $.02



Jay

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[ds968]

btw, my car was dynoed ( all three runs ) in 4th gear and I subsequently heard from a couple of people that you should always dyno in 3rd gear for a truer hp reading, one which will invariably be higher than what you produce in 4th. Is this nonsense or is there any truth to it ? <img src="/forum/images/smilies/968/huh.gif" class="smilie" alt="" />

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[flash]

ah goodie - another chip discussion - lol



what you gain with a higher rev limit is overrun - in the case of high rev downshifting, this is very important - it also becomes increasingly important if you have a light flywheel



cutout costs you time for recovery - having a bit of headroom eliminates that



that being said, having a high rev peak really isn't terribly helpful unless you plan to be up there to use it - for a street car, it is better to have the peak occur lower, allowing a quicker achievement of peak power - it is also best to have the widest torque band possible



after comparing curves, this has thusfar been best achieved by the rs barn chip, outdistancing the previous winner (speed 6)



which dyno it is tested on also plays a role in this - dynos with a load applied will tend to show peaks lower than ones without - roller sizes affect the readings too



in trying to attain high numbers, you have to use the same method of testing as they did originally - typically this means a dyno with no load - this is because they don't usually want to show lower numbers (it doesn't sell performance cars as well as high numbers, though occasionally it gets you past the feds) - the numbers are "real", but not as "real world" as a dyno that provides a load to simulate road conditions



none of this though is what most would call a huge difference in chips - there are a couple of ponies out there, and a bit more flexibility, but it is not going to be a night and day difference from one to the next - you'll see it on a dyno, and may even see it in lap times, but you probably won't feel it in the seat of the pants



where you will see a difference between the rs barn and the promax 7100, is the upper end rev flexibility - i have found the promax 7100 to run out of room just as i was reaching peak, and slamming into the limiter on downshift - the rs barn chip has a slightly higher rev limit which resolves this



the other thing i did not like about the promax was the A/F curve - on yours it is even more exaggerated than others i've seen and is VERY lean down low, at about 14.5 - this is great for emissions, but lousy for power - then it gets really rich up top - i'd prefer to see a flatter curve for more even power



your chart shows a pretty big torque dip at about 4600 too - that is the first time i've seen that, and while other runs i have seen on the promax showed less torque there than other chips, i have not seen that big of a dip



as for what gear to run in, the closest to 1:1 is the best

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[JWahlsten]

Flash,



Your reply answered most of my questions.



I need to go search to see more info...



Thanks,

Joel

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[flash]

no worries - happy to help

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[Fox944]

[quote name='94SilverCab' post='42423' date='Oct 16 2007, 09:55 AM']So what's the point of upping the rev limit if you don't gain anything?...if you get to 6,600 it seems reasonable that you should be shifting unless you have an overwhelming reason not to...



Just my $.02



Jay[/quote]



Most cars make peak HP before they reach their rev limit. Taking the car to right under rev limit before upshifting will land you higher up in the rev range on your next gear...placing you closer to your peak power in the powerband....effectively making you faster.



To give you one example, My buddies RSX Type-S ran 15.1's upshifting @ peak (7900rpm), running the car to its 8300RPM rev limit he was able to break 14's down the 1/4.

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