PT4000 report back / foot brake won't hold it
#22
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Man-o-man alive. You folks have got me so pumped right now ... can't wait to get back out to the track and hammer this converter. I feel kinda' stupid for trying to launch like I have been doing. It's just what I thought was supposed to be the correct way to launch.
As for a long burnout, I have that down to an art and no problems doing a good one. I go around and back up to the waterbox about 10 feet away where there's only a trace of water. I normally jst let it sit and spin for about 5-6 seconds in first and then ease off the brake while the pedal is almost buried for about another 2-3 seconds. Last night, I was just doing the 2-3 second burnout testing the new converter ... easy-at-first.
No wonder I've been so frustrated trying to 60' better. Wish me luck next time out next Friday. Once I get the launch technique down (what works best for my car), I'll start suspension adjustments and tire pressure testing ... one adjustment at a time. Once I get it all dialed in, what do you all think the car is capable of running?
As for a long burnout, I have that down to an art and no problems doing a good one. I go around and back up to the waterbox about 10 feet away where there's only a trace of water. I normally jst let it sit and spin for about 5-6 seconds in first and then ease off the brake while the pedal is almost buried for about another 2-3 seconds. Last night, I was just doing the 2-3 second burnout testing the new converter ... easy-at-first.
No wonder I've been so frustrated trying to 60' better. Wish me luck next time out next Friday. Once I get the launch technique down (what works best for my car), I'll start suspension adjustments and tire pressure testing ... one adjustment at a time. Once I get it all dialed in, what do you all think the car is capable of running?
Last edited by JEB99TA; 03-29-2008 at 04:31 PM.
#23
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ummm yea. floor the go pedal! if you have the right tires (and i have always said to ditch those 17" wheels if you are into drag racing) then the converter will do its job. i always kinda chuckled as i have been following your posts and progression when you said you didnt need a bigger drag tire and how it will slow you down. my car is a 10 second car and i love running these 325 massive radials. they dont ****** spin!
sounds like you are having fun and learning a bunch about your car.
sounds like you are having fun and learning a bunch about your car.
John, I've always followed your posts. While at times you've been harsh, other times you've been very helpful. The added rotational mass of those 11.5" AFS ZR-1 wheels with 315 MT DR's were hurting my MPH and multiple timeslips show that.
I do now see that I need some lightweight drag wheels and 315's is what I need with this new converter to nail it off the tree. So, you were very right in saying more tire/15's. Now, I see what a newb I am and have been, but, because I have listened to guys like you, I'm getting pretty dang good at racing and have learned an awfully lot.
As I take off weight this year, I'm looking at the new Greg Weld drag wheels/skinnies. As I approach 10's, I'm thinking maybe 26x10x15's ... since I plan to stay all motor for awhile.
Thanks for all your help John ... and everyone else, as well.
Jack
#24
9 Second Club
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id do a 275 radial. its not the width you need its the sidewall. and you dont need a 28-30 inch tire. john is set up for a 28" tire thats why he uses the 325. plus it just looks pimp. there are several guys cutting 1.5 60's with the tire you have so id work with what you have unless it just wont work then trade up. i have more money then i care to think in my current car and i fight it every time i go out and have still yet to get it where i can go out and know whats going to get me down the track. my other car was very simple and i drove up-ran my times and drove home. start doing your burnouts with the car in 2nd gear also. it will shift pretty quickly when u get them rolling in the burnout box. then give it a couple seconds. you dont need huge smoke shows but more tire speed in the burnout with give you a better tire on the line.
#25
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I would stall up Yanks to 1500, and I'd smash the gas pedal down when I got off the brake at the line... went 1.50's back then. I'd run the front shocks at 2 soft and rears at 7, and then adjust from there. I'd run radials at 17 cold, and slicks at 14 cold to start.
#26
11 Second Club
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Dang-it! LOL! No wonder I'm stuck at a 1.7 60' time ... I could kick myself ... was just always afraid of wasting a run because I though that would blow the tires of the car. Thanks for the pointers fellows. I guess my first couple of times racing last fall made me really paranoid. It Wednesday night/ricer night and I was spinning pretty bad. I was backing too far into the water box and didn't know to leave in the groove of a few big slick cars. I'm getting comfortable with everything now. Caveman's given me some very helpful advice along the way and it's helped a lot.
Check out the video in my sig....I stalled my PT4400 to about 2500 and mashed it on the light. I too was afraid my 17" MT's wouldn't hold but they surprised me. I was expecting 1.7x's and was absolutely thrilled with this 1.63. This is with 3.23's, full weight and Bilstein suspension. You've got 1.5's coming....just mash it and try not to smile too much! I think I had better times coming with more seat time, but I only got a couple runs that night and haven't made it back since.
#27
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Last year I ran the PT4000 and would average 1.50-1.52 60-ft's leaving from 1200 rpms. I tried launching from 2300 rpms and hit a 1.48. I run 16" MT DR's so big burnouts are needed. See link in sig for my best run last year.
#28
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Damn! I just never thought the tires would bite if I stomped it off the light like that. The car was built for mid 11's NA. When the motor was built, the ringlands were set up for a 150-200 nitrous hit. I probably will eventually go the FI route instead of N2O (if I ever save enough money), but, for now it looks like the car might see 10's this fall if I can do enough weight reduction. Again, I never knew I could hit the converter off the line so hard. I think Friday night will yield some decent 60' times and better ET/MPH.
#30
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Matt, do you have racing brakes that allow your brake pads to stay locked on to the rotors at that high of rpm? Whenever I stall it up over 3000 rpm, I seem to always nudge the beams. I was thinking you might have a 4 or 6 piston brake setup that allows you to hold it at that high of a stll.
#31
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Matt, do you have racing brakes that allow your brake pads to stay locked on to the rotors at that high of rpm? Whenever I stall it up over 3000 rpm, I seem to always nudge the beams. I was thinking you might have a 4 or 6 piston brake setup that allows you to hold it at that high of a stll.
As most have already said the convertor stall RPM does not mean you can footbrake to that RPM. You do not want to use a line lock at the line as a matter of fact most tracks do not allow it. I think it is even a IRHA/NHRA rule. The last thing you want is when you launch the line lock sticking and the front wheels locked. I would have one on the car so you can do you burnout without having the back brakes having pressure on them.
One of my sponsors who builds transmissions for a living and races his a 3rd gen T/A which runs 5.20's in the 1/8 told me that it is real hard on the convertor leaving at idle. Some people have said to stall around 2,000 to 2,500 this is good advice. Test the stall and see which one gives the best sixty foot move up in 200 RPM steps until you sixty goes down.
One thing to remember the lower the RPM the slower the car reacts which means your reaction time will be slower. As you get use to the car with the changes it will come around.
My car flashes to around 4,500 RPM's and it pushes through the lights at 3,400 RPM's and slows down when I launch any higher than 3,000 RPM's. It has run a best of 10.75 at 123.5 MPH with a 1.41 sixty foot.
N2
#32
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N2 ... where you form in Tn? I'm originally from Harriman. Born and raised there 'til I left for the Army at the age of 21 ... never went back except to visit family, but, plan to settle in East Tennessee when I retire.
I plan to start at 1800 rpm and stomp the **** out of the pedal. I'll work up from there. Gotta' try it from 1000 rpm at least once to see how the car reacts. Thanks for your advice, brother.
I plan to start at 1800 rpm and stomp the **** out of the pedal. I'll work up from there. Gotta' try it from 1000 rpm at least once to see how the car reacts. Thanks for your advice, brother.
Last edited by JEB99TA; 03-30-2008 at 07:05 PM.
#33
Retired Street Racer
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Matt, do you have racing brakes that allow your brake pads to stay locked on to the rotors at that high of rpm? Whenever I stall it up over 3000 rpm, I seem to always nudge the beams. I was thinking you might have a 4 or 6 piston brake setup that allows you to hold it at that high of a stll.
#34
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I had the HAWK+ pads and swapped them back to the GM stockers. I can see where the Hawk pads would hold better, especially if you 'burned them in' when you installed them.
Your car's coming along real nice, man. I'll be PM'ing you for some weight reduction questions soon. Thanks Matt.
#36
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Run both front and rear shocks soft, 1 or 2. Soft in the rear allows the body to come off the rearend quicker..assuming you have relocated your lower control arms.
To get goood reaction times and normally for a faster pass, I have found holding at 2000 works best. Assuming the guy next to you has his first bulb lit, hold yours at 2000 on the first bulb and walk your car into the 2nd. You are ready to launch at this point. For us guys with trans brakes and 2 stage rev limiters, this is where we hold the button and mash the throttle. And I have my line loc also wired to the trans brake switch.
Good luck, the funnest part is the first 1320 ft!
To get goood reaction times and normally for a faster pass, I have found holding at 2000 works best. Assuming the guy next to you has his first bulb lit, hold yours at 2000 on the first bulb and walk your car into the 2nd. You are ready to launch at this point. For us guys with trans brakes and 2 stage rev limiters, this is where we hold the button and mash the throttle. And I have my line loc also wired to the trans brake switch.
Good luck, the funnest part is the first 1320 ft!
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95 Pontiac Formula- Stock engine with ATI Procharger, Moser 12 bolt w/4:30 gears, Rossler trans, Neil Chance 4000 stall, M/T ET streets, 10.914@ 121.90mph, 1.452 60ft. GMHTP November 2010 Feature Car. Check it out at:
https://www.motortrend.com/features/...ebird-formula/
http://www.youtube.com/watch?v=abZ1z...ature=youtu.be
95 Pontiac Formula- Stock engine with ATI Procharger, Moser 12 bolt w/4:30 gears, Rossler trans, Neil Chance 4000 stall, M/T ET streets, 10.914@ 121.90mph, 1.452 60ft. GMHTP November 2010 Feature Car. Check it out at:
https://www.motortrend.com/features/...ebird-formula/
http://www.youtube.com/watch?v=abZ1z...ature=youtu.be
#38
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Some great info here. If traction is not a problem this Friday night, anyone care to guess what might gain by slamming the pedal to the floor as compared to just rolling into the pedal like I've been doing? Maybe +.2 60' / +.2 ET / +2 mph? Is it possible I could do that much better? Times are in my sig.