New Best

[neverfastenough]

BTW you might not want to beat those tires up too much. I also run a 26in slick with 2.73 and trapping 104, my tach was around 5500. Its probably not accurate, but just a thought. I figure you make more power than me and will trap faster. You have H/C tho and your engine might like 5500rpm. I know mine quit making power at 4600 on the dyno recently. I think 28in might be a better option. However, Im only 280ish and with 2.73 and 28in, I might bog a bit much. Some fancy clutch work might fix that. You are also more ACT limited than me with your IC, so excessive rpm at the big end might not be a good thing for you. Im sure you thought about all this tho, its not your first rodeo.

[fturner]

Originally Posted by neverfastenough

BTW you might not want to beat those tires up too much. I also run a 26in slick with 2.73 and trapping 104, my tach was around 5500. Its probably not accurate, but just a thought. I figure you make more power than me and will trap faster. You have H/C tho and your engine might like 5500rpm. I know mine quit making power at 4600 on the dyno recently. I think 28in might be a better option. However, Im only 280ish and with 2.73 and 28in, I might bog a bit much. Some fancy clutch work might fix that. You are also more ACT limited than me with your IC, so excessive rpm at the big end might not be a good thing for you. Im sure you thought about all this tho, its not your first rodeo.

From some testing I've done, and the way the valve train has been setup, the car should be good to 6000... if I went to a bit more duration with the cam then I can easily run it to 6500. Can't do that with the convertor I have so the car hasn't seen 6500 yet.

Fraser

[neverfastenough]

Originally Posted by fturner

From some testing I've done, and the way the valve train has been setup, the car should be good to 6000... if I went to a bit more duration with the cam then I can easily run it to 6500. Can't do that with the convertor I have so the car hasn't seen 6500 yet.

Fraser

Cool beans, should work out nicely.

Corey

[David Neibert]

Originally Posted by fturner

Went to the track today, with my new MT ET Streets . These are the bias ply ones that are 10.5 wide by 26 fitted onto a set of sc rims.

Best run
R/T - .487
60' - 1.997
1/8 - 8.780
mph - 82.01
1/4 - 13.583
mph - 102.63

Next best run
R/T - .453
60' - 2.046
1/8 - 8.848
mph - 81.54
1/4 - 13.661
mph - 102.28

I steadly improved as I got more and more used to the slicks and the way the car hooked up, and I'm developing a launching pattern so to speak that seems to work best with the current setup. My trap speed is way down from a best of 105.9mph but thoughts on that is because I'm not getting enough rpm at launch now that I used to get with spinning the street tires at launch.

Fraser

It's normal for mph to be lower when the tires hook up. Looser converter, or more rear gear would help the most. You can also try holding the throttle at 1300 rpms on the line and floor it from there while letting off the brakes at the same time to flash the converter a little higher.

Loading the converter all the way to stall is only something you would want to do if you were spinning the tires real bad and it doesn't sound like you are.

David

[91bird]

Great run Fraser, looks like you have everything going in the right direction.

Drew

[90blkbrd]

Originally Posted by David Neibert

Loading the converter all the way to stall is only something you would want to do if you were spinning the tires real bad and it doesn't sound like you are.

I'm confused. I thought you should load the converter all the way up to stall and let her rip. If the tires spin then you should step it down in RPMS until you get traction. I did this at the shootout in Ken's car and got a 1.7x, the best 60 foot his car has ever done.

[XR7 Dave]

Originally Posted by 90blkbrd

I'm confused. I thought you should load the converter all the way up to stall and let her rip. If the tires spin then you should step it down in RPMS until you get traction. I did this at the shootout in Ken's car and got a 1.7x, the best 60 foot his car has ever done.

I would say that "personal experience" is the worst place from which to try to gain scientific proof of anything. There could have been 30 different factors that played into your "best 60 ft". In real racing one would never flash the converter from idle to get a higher stall speed because doing so will screw your reaction times up and make it impossible to really run consistently. In racing people generally choose the correct stall speed so that they don't have to pull tricks to get a good launch. It is conversely quite common for street cars to do all kinds of tricks to try to improve a launch. Just how effective one is vs. another is a matter of determining the weakest link as David alluded to. There are many factors - track prep, tire heat, suspension compliance, available torque, etc., that all affect initial bite and therefore the stall speed that will achieve maximum launch for any given set of "street car" parameters. Therefore don't just assume that what seems to "work" for one person is going to work for the next.

You all might want to ponder how it is that Dan McEwen manages to get 1.8 60fts on real street tires with his mid 13 second car.....

[fturner]

Originally Posted by XR7 Dave

I would say that "personal experience" is the worst place from which to try to gain scientific proof of anything. There could have been 30 different factors that played into your "best 60 ft". In real racing one would never flash the converter from idle to get a higher stall speed because doing so will screw your reaction times up and make it impossible to really run consistently. In racing people generally choose the correct stall speed so that they don't have to pull tricks to get a good launch. It is conversely quite common for street cars to do all kinds of tricks to try to improve a launch. Just how effective one is vs. another is a matter of determining the weakest link as David alluded to. There are many factors - track prep, tire heat, suspension compliance, available torque, etc., that all affect initial bite and therefore the stall speed that will achieve maximum launch for any given set of "street car" parameters. Therefore don't just assume that what seems to "work" for one person is going to work for the next.

You all might want to ponder how it is that Dan McEwen manages to get 1.8 60fts on real street tires with his mid 13 second car.....

Printing his own time slips out on an ole epson dot matrix printer

Fraser

[fturner]

Further study of my datalogs and discussing with Dave Dalke, the other thing that for sure killed my mph is the fact that almost every run started out with act's at 120 so timing was getting yanked as soon as I launched.

Before, no timing was getting yanked on the street tires because the car would just be tickling 120 at the top end.

Its the burnouts causing it, and line locks are going in the car so I don't hold the back brakes on while doing the burnout. Temps shouldn't go any where near the 120 I was getting before.... meanwhile, I'm heading to the track on Sat by the looks of it, and I'm going to try doing very short little 3 seconds burn outs just to clean the tires and see... not sure though if traction is going to be issue without some heat.

Fraser