Jake951

As I reported in another thread, I just did a third gear 60-100 mph run in 5.9 seconds up a slight incline on an 82 degree day. Only thing is, I know my speedometer reads about 3% high because of tire diameter error, so it was really a 57-97 mph run. I would have had to shift to fourth to make a true 100 mph without redlining the engine.

951and944S

I don't really see twin turbos giving any real world advantage to our existing setup. Small displacement engines can't really benefit from two turbos. The six cylinders get away with it only because they have more exhaust pulses per engine revolution.

Secondly, re. the point on Toyota=success, Toyota reportedly has a 1 billion dollar, 3 year budget in their attempts to align themselves with the world's elite auto makers who reign at the top of the F1 food chain.
That's 333 million USD per year. Their driver's salary budget is miniscule (DaMatta and Panis) compared to teams such as McLaren/Mercedes, Ferrari, and BMW Williams so most/more of their money goes towards R&D and while they are making decent power they thusfar have not been able to match the Italian or German engine manufacturers for reliability or pace.

Terry S.

Danno

"It amasses and frustrates me every time I think about the racing heritage, German precision and technology the Porsche name carries..... then a frickin' Honda makes me eat dust at a red light."

Yeah, but when was the last time Porsche won the F1 World Championship? Also we're driving 20-year old cars. If we used Porsche's latest technology, like the GT2, and chopped off two cylinders, we'd have 350bhp to play with.

"I think he said before that he knows the guy, and it does have a single leaf-vacuum sized Pratt & whitney ridiculous turbo on it."

Yeah, the big TO4S turbos used in these monster Supras measure about 12" in diameter with a 6" inlet. Imagine putting up our K26/6 as comparison, it would fit entirely within just the inlet of the monster Supra's turbo!!!

"I don't really see twin turbos giving any real world advantage to our existing setup. "

Yeah, performance wise, sequential twin-turbos won't generate any more peak-HP than a parallel twin-turbo or even a big single-turbo that flows the same CFM of air. But what it does is gives you a wide and flat torque-curve. It eliminates the lag associated with turbos, especially the high-boost ones. The torque-curve has twin torque-peaks with a wide valley stretched out between them. On the SupraTT, the first torque-peak occurs @ 2500rpm and many of the BPU++ cars can generate over 300 lb-ft TQ at 2500rpm! Then the torque rises linearly to 600 lb-ft TQ @ 5500rpm. This convex torque-curve (looking from top down) makes launching such a powerful car much easier without uncontrollable wheelspin like our 951s. A single-turbo 951 would make 300 lb-ft TQ at 4000rpm and jump up to 600 lb-ft by 5000rpm. This sudden increase caused by the concave torque-curve wastes a lot of power in wheelspin rather than launching the car down the road. A 550rwhp SupraTT will typically do 0-60 in the high 3-second range, 1/4 mile in mid 11s and 0-125mph in 10.5s. About 0.5-1.0 sec. faster than a 400lb-lighter 951.


Another test point:

GURU-test car @ 15psi (13psi @ redline)
262 rwhp & 303 lb-ft TQ (notice the wide torque-curve)
0-60: 4.7-4.8s
1/4-mile: 13.2-13.4s

Konstantin

third gear from 4000 to 6500 rpm and you get an acurate run from 60 to 100 mph (or 100-160 km/h)
I always shift at 6800 rpm and no problem till now. My car has 240000 km and had some hard runs at the Autobahn ;-)

Konstantin

Jake951

The only thing about revving above 6400 rpm is that the rev limiter kicks in somewhere not far above redline. I'm not sure exactly where but I've hit it once before during a highway run and it scared the $#!@* out me.

Konstantin

but only with stock chips. With aftermarket chips you can go up to 7000 rpm for the rev limiter

Konstantin

Jake951

I have the GURU chips+MAP. Danno can tell us about how the rev limiter is programmed in his chips. I know that I've hit it (or at least something triggered fuel cutoff) during a test run. The last point in my datalogging file during that particular run was around 6500 rpm in third gear before the cutoff kicked in. It felt like I had suddenly slammed hard into a brick wall and I thought I had destroyed the engine. It took me a few heart-stopping moments to realize what had happened and that everything was OK. I sure don't want to try that again...

Magown

I believe in a previous post Danno said he left the rev limiter stock on his chips.

Magown

You guys should all just buy a gtech pro competition so we can compare results files. If anyone wants see my gtech files feel free to PM me.

My best results on my '88 w/140k miles and low compression on two cylinders 1.1 bar.

60ft 2.313 s
330ft 6.048 s
1/8 mi 9.088 @ 84.35mph
1000 ft 11.608s
1/4 mi 13.72 @ 105.44
0-60 5.848 s
0-100 12.364 s
calculated 60 - 100 6.516
50-70 2.452 s
60-80 2.452 s
Max G's .71

3rd gear pull from 2500 rpm
Max HP 225.7 @ 5654 rpm
Max TQ 231.2 @ 4523 rpm

Blueman33

As far as Rev limiter.

Looks like to me if Porsche designed a car that limited the revs to 6500 or wherever, that's for safety.

I would NOT increase my Rev limiter because it is not to protect the 'chip'; it is to protect the other components. The engine was meant to max out at 6500, so that's what i'm sticking with.

The boost is dropping off at that point and the car wants to shift anyway.

Just my opinion

Ahmet

Yeah, I'm running Boge OE shocks, and original brake pads. I also have some 15+year old good years I just picked up. There's stickier tires out there, but I wouldn't want to overstress suspension components, Porsche chose the tire that they did for a reason. I wish they still made casette tapes, as I'm not replacing the original blaupunkt that came w/the car, the CD noise could interfere with the factory engine controls. I would upgrade my speakers, as they don't sound their best, but it could overload the wiring or the internal amp of my casette deck, I'm sure Porsche had a reason for that too. Bah!

It doesn't make too much sense to rev most 951s out there past 7k, but not doing something because "Porsche didn't do it" isn't that good of a reason, specially considering "Porsche didn't do it" 15+ years ago...
Ahmet

toddk911

Magown:

That 60ft time I would have expected to be a little better. Was it a problem with the car bogging on launce or wheel spin??

What weight did you enter for the hp runs??

Magown

I dunno how much more time can be shaved off that 60ft time in the cars current condition, it's definitely a result of bogging. My best G-tech 60t time is 2.29. It's kinda hard to explain how I did it, the g-tech data log does a great job of showing you what works best.

The problem with my '88 is it has low compression on 2 cylinders, off boost it's a real dog. I used 3000lbs on the HP run it was a 3rd gear pull.

One thing to point out, the Gtech's logged rpms are higher then they really were on the 951. It shows me shifting at 7200 rpm. In reality I never did more then 6400 rpm. I'm not sure why it was off in the 951. It was dead on the money in my Volvo.

Konstantin

because you conected the RPM signal to a wrong place. you must conect it directly to the DME or KLR then the signal is good and it works fine. same for the AVC-R

Konstantin

Magown

Konstantin, to my knowledge there is no other way to connect other then pluging into the cig lighter.