mark kibort

That is the REAL difference here with you vs me, Dave. I'm here to help, and you are hear to premote yourself. Very clear now! knock -your-self-out.
You dont have a porsche, you are not contributing, really, unless you are gettting paid. Hmmm, very telling.

I think any of us in the know, now see your problem with the concepts. you are confusing a falling HP curve with a post shift reduction of HP. just because HP is falling, it doesnt mean that you are accelerating less than a rising HP curve. (kind of reminds me of the one confused sole that didnt understand that when you lift to shift, you actually decelerate! he was confused with the force, and momentum concepts) you call it google, i call it an expensive education, and in the end, the education really did involve "real world" information too.

The fact that you think a falling HP curve is slower (less acceleration) than a rising one, is amusing. really. now, you cant tell us why, because its your proprietary information, and their "competitive advantage" . Thats funny and very convenient. I hope , no , Pray, i meet one of your students in one of my races this year! Better yet, YOU ! High Plains Raceway!

Anyway, Garrett's graph does fall off before redline and that fall off is still showing more hp available than a post shift level. PLUS, if you are approaching a braking zone, and you might not have to shift as you go to redline, you now shift and lose not only 300hp or so, but negative braking 20hp for coasting. Put .3 to .5 sec of braking power, for that time sequence, into your equations for acceleration where you have decelleration for a shift during that straight.


So to summarize , and make clear to anyone that wants to use YOU as a racing resource, to maximize performance, you think the acceleration of a falling HP curve at a higher HP, creates less acceleration than a rising one with a lower HP level. Got it.
And, that the point at which the rising HP curve is caught by the next gear being at a lower HP, doesnt mean anything either? Got it.

VR, this really shows your value as a coach. First . inability to really understand the information or read a graph correctly. Second, inability to learn something that you may have have not known before. Nothing worse than a player or coach with a closed mind.

Veloce Raptor

Another day, yet more insults & personal attacks, Mark? Aren't you the same guy who has repeatedly whined about same?

No wonder no one wants to discuss anything with you.










Professional Racing and Driving Coach

mark kibort

which ones of these dyno runs is VR Dave Scott, refering to?'

Garrett, are both of these from the same car, different engine, or different all together. you claimed both of them.

Eitherway, both pay to shift at near redline, if redline is 7300rpm.

why? because the HP after the shift is much higher than shifting earlier , and the pre shift level of HP is much higher than the post shift level of HP.

bottomline, if you ever, putting down more power, you are accelerating faster. its really that simple. (and thus you will be putting down more rear wheel torque)

by the way, take the graph numbers and multiply the values by 3.44. that will give you the real differences in torque found at the rear wheels if you short shift. basic physics! some differences are near 300ftlbs! by short shifting.
do that on the main straight of willow springs or Cal speedway and you are going to be left in the dust by someone that is NOT listening to VR.

Veloce Raptor

..

himself

Not to add more fuel to this fire, but I'm still not going to shift at 7000 RPM in my 3.6L 996. Doesn't seem like a good idea...

-td

mark kibort

No fuel on the fire...., good discussion.

why is it you feel its not a good idea. do you have the HP curve handy? or did you post it before?

remember, all of those values below are multiplied by 3.44 to show the real difference in torque to the rear wheels.

why does this go to 8200,is this not a street 996 engine, or something else. what redline are you refering too. redline stock or this new redline of 8200rpm.

what are the highlighted areas meaning?

Mk

mark kibort

news flash, this discussion isnt with you Dave, you have not posted anything worth looking at. and infact, you have only commented and made errors of your assesment (verified by greg and others) of the main thrust chart. When asked about your reasons, you just bow out and say , "proprietary". You then correct yourself, and say, "maybe for 5-6th gear as was the main issue with Brinkely." but, when called on that as well, you just remain silent , start back pedaling, and then refer back to your "data" for truth.
You are like a religous zealot!
So, you havent really entered into the discussion, except for saying that we are "wrong".

no whining here , just disucssing.

JustinL

Also curious what engine this is. GT3? What do the blue highlights represent? This looks like a car that is very well geared for it's power delivery.

quickxotica

Poll needs an fifth option:
5. I drive the entire track at redline in 1st gear to sustain maximum wheel torque.

Speaking of North & South Korea: The only thing more frustrating/entertaining than this thread would be watching a death-match between Sarah Palin & Kim Jong Il, each armed with nothing but goose down.

TGIalmostF@RL

mark kibort

for a autocross that would work.

its the same gearing as the 996 3.6, right?
where would you shift it if it was your car? (on a long straight that is! )

JustinL

If someone else is footing the maintenance bill... then 8200 would maximize acceleration all else equal. Though I think the 996 GT3 has gear dependent rev limits.

himself

Discrete components of curve are posted in my excel sheet above. Some of the items are extrapolated from the curve.

TORQUE: I have a fairly flat torque curve:

• 240@2600 RPM - generally rising to a high of
• 289 @ 5000 RPM (high) which is a typo in my spreadsheet, but it's too late to fix it now), slowly dropping to a second low of
• 240 at 7700.
• There are a few little crests/valleys in the graph.

HP [corrected] :

• 120 @ 2600 rising to
• 280 @ 5000 and on to
• 373 @ 7321 and then tapering off.

This is a street GT3 with a stock 3.6L flat six, pushing 380 HP [factory claim]. The stock redline is 8200.

Green is max torque RPM [5000 RPM with 279 (typo as noted above)].
Grey is gear down location [i.e., shift from 8200 in 1st results in 4500 in 2nd]
Yellow is Max HP @ RPM [373 @ 7300]
Blue is overlap with max tq from next shift.

-td

mark kibort

Got it. thought it looked a little stout and high strung!

anyway, we were talking 996 street, but, you have a couple of short shifts noted and I think you would be better served by redlining at 8200 and I posted some pointers on your graph.

also, a graph of the 996street motor and why we should shift it at redline as well

the red boxes are redline shifts
the blue boxes are 7300rpm, incase this was a 996 street motor with mods
the green boxes are it looks like, your short shift points.

on the second graph, the points are self explanatory.

From Garret with RPM drops vs GT3:
Here's my 996 that I run:
(stock gearbox with these ratios:
1st gear 3.818 vs GT3 3.82
2nd gear 2.20 57% vs GT3 2.15 56%
3rd gear 1.516 68% vs GT3 1.56 77%
4th gear 1.216 79% vs GT3 1.21 82%
5th gear 1.024 84% vs GT3 1 82%
6th gear 0.841 84% vs GT3 .85 85%
Final drive 3.444)



can you post your GT3 street hp curve??? thanks

Mark

JustinL

Blue is information only, you are not required to move over.

garrett376

Yes, these two different dyno graphs are from the same "car" but with different engines installed. Due to the "dead" engine that has no guts above 5000rpm, I swapped engines between this car and my street car since the x51 engine won't get me to work any faster, but the increased power is a lot more fun in the track car.

This is an interesting discussion (the technical stuff part of it)... gives me something to think about at the POC willow springs races this weekend!