IPSC

Wow I am having a hell of a time breaking 270RWHP on a k27/6 with a gutted cat, 38mm Tial, 3 inch cat back, Vitesse MAF & chip board along with 72 lb injectors, AFPR running 44 psi.

I am thinking I need a Vitesse Stage 3 turbo and piggy back / full 3 inch exhaust to get up into the 340 area.

Also very cool that you are the original owner. That right there I find to be a very cool thing indeed. So what was it like rolling off the lot in 89 with a shiney new 951?

IPSC

Rogue_Ant

That hasn't been my experience - especially at altitude...






Same pull - first one uncorrected, the second SAE corrected...


Rogue

Jake951

Oops. You're absolutely right. I was thinking sea level only.

Jake951

This may seem hard to believe today, but in 1989 the Porsche dealers could barely give away any of the 944 series cars including the Turbo. I was driving an '86 944 NA at the time. They offered steep discounts to move the vehicles off their lots. I bought mine for nearly 25% below sticker, which was a deal I found hard to refuse.

M758

Wow that does seem really really high.


A few years ago my stock Turbo S made 230 whp on a dyno jet. I considered that really strong for stock car that has never been opened. Chris Cervelli did the dyno work on it and also said it was strong for stock car. I always figured with a chip I could reach 270-275 whp and MAYBE.... just MAYBE hit close to 300 with a MAF. There is local guy here with an 89 and with a chip, maf & tuning said he is at 300 whp. I don't know the boost levels.

That just seems really really strong for that low a boost pressure. Are you certain you got an accurate boost reading? Is that 16 -14 PSI really 18-16, or possibly 20-18?

Tms951

Are you sure that is not at the flywheel. Dyno Dynamics Dynos have it so you can display either whp or have it convert it to Fly wheel.

Another thing about that dyno is I know it was broken in March. I had some initial tuning done there. It was reading way low. I maxxed out 72lb injectors and it was reading like 270whp. They told me it was broken and reading low, and that every car they put on it seemed like it was reading lower and lower. They said it was ok for tuning because it still showed a difference. At that point in time they were trying to get it fixed.

I have operated a Dyno Dynamics when the shop I work at owned one and you can skew the numbers however you want when you set it up. You just put in a multiplier and it skews it for you. I also know that when the shop i work at had one it broke alot and getting fixxed was a pain in the ***. The only people that can fix it is the inporter Aussie Imports. It took them forever to come fix it.

I wonder if KTR has a multiplier put in, or if those are flywheel numbers, or if they got it over fixed and it reading wrong still but not it is just high.

I will post my dyno from there when I get home.

Jake951

Actually that's one thing I'm NOT certain about. As I said earlier, my own VDO gauge shows around 16 psi (on the road) in the rpm range where the dyno's sensor shows around 14 psi.


Yes, I'm sure that it's at the wheels. It's always possible the dyno operator messed up the calibration or the dyno is out of whack. There's just no way to know that for sure.

As I said before, this same car has previously done 297 rwhp/317 rwtq on a Dynojet when I was running the Guru MAP at the same boost settings. The Dyno Dynamics numbers show an increase of "only" 10 lb-ft and 20 hp with the Vitesse MAF. It's always possible, too, the Dynojet numbers were wrong. If you optimistically allow for a +/-5% error in any dyno (I don't know of any chassis dyno that can claim to be more accurate than that), then the latest numbers aren't tremendously different than the old ones.

I think the bottom line is that any dyno numbers really should not be used to compare with another dyno's numbers. The dyno is a useful tuning tool if you get baseline numbers on a particular dyno and do all your tuning on the very same dyno to compare to your baseline. Otherwise we can assume that all dynos lie.

Laust Pedersen

Sorry for going a little out on a tangent, but:

What is the meaning of altitude compensation in a turbocharged car, where the boost is regulated to an absolute pressure?

Sure, the turbocharger is working a little harder (higher pressure ratio), but if it has the capacity to get to the desired (absolute) boost pressure in “thin air” then the cost would only be a few HP.

A compensated dyno chart should show how the car would perform in a normalized environment (temperature, humidity, pressure [altitude], etc.), so by that standard the compensation factors should be significantly different between a normally aspirated car and a turbocharged car with a boost controlled to absolute pressure.


Back to Jake951’s car: If the load of the dyno is adjusted to the actual inertia (weight of the car then 15.8 psi of boost at 3700 rpm is a little late for a K26/8. There are also some funny small kinks in the HP/TQ lines at 4700 and 5700 rpm. I too find the numbers “unusually healthy”.
How about some real life 60-100 mph and/or 100 – 200 kph times as a reference?

Laust

95Juan

IIRC, Russel and Lindsey Racing had an 89 that was running 300+ on a 26/8 with stock AFM, russel's chips, exhaust and a wastegate

yep-

http://forums.maxhpkit.com/viewtopic.php?t=24

towards the bottom.


although 300+ with the stock exhaust is really strong.

IPSC

WOW that is all I have to say to that. No wonder 89 was the last year they imported them. Good for you though.

IPSC

Rogue_Ant

Laust,
I agree that if the turbo would be able to achieve the same (absolute) boost pressure... However, at my altitude I start with ~3psi less air pressure, and my small K27 was unable to cover the spread. I did that pull with my boost controller attempting to achieve ~22psi, but by redline actual boost was only ~17psi. I do think the 'corrected' number was a bit optimistic, but if I had 3psi of extra air-pressure (sea-level) I do believe I would make quite a bit more (uncorrected) HP.


Rogue

Jake951

Agreed, assuming that you are using 4th gear boost profiles for comparison. As I stated earlier, the dyno operator did the runs in third gear. That shouldn't affect the peak numbers but I think it doesn't allow the turbo to develop the lower rpm boost that it can get in 4th gear. In the past I've been able to hit at least 10 psi at 3000 rpm in 4th gear, whereas here I get only 4 psi in 3rd gear.

Yes, I noticed those, too. The one at 4700 has shown up in other dyno runs I've done in the past. I'm not sure what causes it, but it I saw the same kind of bump when I was running my old Guru MAP setup. The kink at 5700 rpm showed up on the final couple runs I did on the dyno (I did a total of five runs). I have a suspicion that heat soak might have been starting to set in and the car was pulling back ignition timing on the onset of detonation.

I did some 60-100 mph runs a few years back before I was at the current level of mods and my numbers at that time on a Dynojet were 260-270 rwhp. I got around 5.7 seconds. I might be a couple tenths quicker now.

toddk911

LOVIN' THE AVITAR!!!!

toddk911

Ayer!!!!! I spent 9 months at Ft. Devens back in 1994

toddk911

Interesting. Take 270whp / .85 to get crank hp and you get...... 317hp. His shows 318??? Just a coincidence??

I'm gonna guess this is corrected to crank hp.

And your 297 run on the Dynojet also could have been inflated as most Dynojets runs are.

If not, then you have one super efficient turbo/motor.