Jean

Kevin,

By time, I meant ET, not trap speed. I agree that the trap speed is a better indicator....HOWEVER, (please dont' think I am disputing how good the numbers are at all!) only when you extract the launch impact!

What I mean is that if you do a 60ft in 1.9 seconds, it means you achieved a 0-60mph in about 3.15 seconds, this on its own will give you better trap speed, since you will have more "road" to accelerate from 60mph to whatever the final trap speed is. ET and trap speed are indeed interelated to a point.

The right measurement, would be to take your speed at 330ft and then your ending speed at 1320ft, and compare speed vs. distance in similarily geared cars..
I know I am pulling hair here, but if it is HP we want to calculate from a quartermile run, this is how to do it IMO.

A quick comment about the max. speed mentioned earlier.. If the engine gets to the rev limiter in 6th gear, and if you have 315s in the back, then you will reach 200mph, the problem is in hitting the rev lmiter in 6th.!

KPG

Aha... you meant ET. We are in total agreement on that. Too many variables in the first 60 feet. Kevin

TB993tt

Kevin
Can you share the technique for doing 0-60 in 3.15s ?

My lame attempts seem to result in rampant wheelspin and or severe tramping and a pathetic ~4s 0-60 leaving me riddled with guilt about abusing my poor drivetrain

Jean

TB993TT, I guess only on drag strips with burnouts etc.. What was your 60ft time on the AX22?

KPG

First of all, stop ganging up on me . I never did check the 60ft time on the GPS because I had the timeslips for that data. I will go back and check although the 0-60 will not be 3.15 seconds as you claim. I am sure you both know this , but the dragstrips have a rollout factor in the timing. When I use my GPS I do not include the rollout in order to have actual times.The timing starts with actual movement measured to the .1 sec. The times posted are tracked by GPS not yaw sensors or accelerometers. The unit has those items but are used for Drifting calculations and G force measurements.Speed and time is a 10 times per second GPS calculation. As for rollout . Milan dragway has a 1 ft rollout. I always short stage, therefore I have about a 10" running start before the beam is released by my front tire rolling away. My best 0-60 time is 3.6 sec flat and I can post any data to that effect you would like. Now, Jean claims at the track a 3.15sec 0-60. Perhaps a 10" rolling start may have some influence on that number. Toby, perhaps you can chew on this time slip. How does a 1.799 60 ft time grab you? That time slip was taken several weeks before these numbers were posted. The setup at the time was: Kevin's turbos, no wastegate upgrade, cam adj solenoid CEL at the track, and my wifes low boost file because Kevin was still writing my 1.25 bar program. That slip was my best time and 60ft, although my best trap was about 123mph. As you can see from my next group of times at the track with my current setup, the ET only went down .002 although trap went up 5 mph+. 60ft times deteriorated as well. The issue was axle tramp. Never had it before and now I cannot get rid of it.Toby, I usually leave the line around 2800-2900 rpm and just feather the clutch and I do not powershift but I do not take my time either.I have too much torque now to get much better 60ft times without serious abuse to the car, which I will not do. You guys are a rough crowd. I have to run out but I will get the data of the GPS for the 60ft run, which will be slower than thetrack due to the rollout issues. Kevin

KPG

Sorry, forgot the timeslip for Toby

TB993tt

Kevin
My question about the technique was genuine, be it 3.15 or 3.6s - Standing starts are not something I have practiced and I am struggling to get below 4.

Autocar mag tested the first 408hp 993tt at 3.7s so I know how cr&p my attempts are - just after some advice

KPG

Toby, I wasnt questioning whether your inquiry was genuine at all. I was trying to keep the facts at the fore front, because the track does have a rollout that affects times. Lets be clear, my 0-60 in 3.6 and your struggle to get a sub 4 sec time is not an equal comparison. I captured my time at sanctioned drag strip. The track is chemically prepped to improve adhesion. Even at a poorly prepped track one cannot compare grip levels to public roads in my opinion. I am running around 18-20 psi in the tires during these times. Although, for the 60-130 times I did have spec infaltion to help offset rolling resistance losses of a low pressure tire. I, like you, have guilt issues related to driveline abuse. I did these numbers with as hard a launch as I dared, I will not do it again unless I have a major change of hardware or software. I am pretty sure my best 0-60 on the street with proper inflation was a low 3.8 sec run. As far as Autocar getting a 3.7, no doubt it happened, but it is amazing what one can do with another persons clutch, half-shafts and input shaft!! Also, I know little of your generation of 911's. My experience is limited to seeing a few drive by- beautiful vehicles I might add! Heck, I see your car is 2wd... I did not even know they were made in 2wd. In the end there are so many variables to consider between similar cars at the same location, let alone two vehicles of different generations separated by the Atlantic. Just two different animals I think. I know your car has the power so I would say keep any launch under 3K and find the sweet spot with the clutch. Good luck. Kevin

KPG

Well,the dyno is going to have to wait. I have postponed it until Mon Oct 23rd. I am sure many on this board are self-employed,as am I, and realize that there are times when work comes before pleasure. Unfortunately. something has come up that I cannot put off, and I will be out of town next week. The dyno tech was understanding, and is willing to try and fit me in before Oct23 if my schedule and his allows. Hopefully this will get done sooner rather than later. Kevin

Red9

Reading launch problems here and on 6 speed that is a universal problem - I keep wondering if anybody has any experience with traction and or launch control . Racelogic or others??

Woodster

I as well as many APPRECIATE all of Kevin1's (and Kevin2's) work!!
this takes time, hell, it took me months before I figured out how to hook
up my AX-22, and then find a "Mexican Road" at the right time when it wasnt raining, etc, etc.
I am also self-employed and was "insanely busy" this summer, Oh well,
I believe the Winter is storing some power for me!

Marty K.

Kevin

Kevin, with the new solinoid installed did you make it back to the track?

KPG

No, unfortunately that work thing seems to be getting in the way! I have the 20th - 2nd off work and will make it to the dyno and the track before the season ends. Hopefully, 50 degreee temp and 315/30 drag radials will show an improvement in times. Kevin