Hemirunner
Well-Known Member
https://www.coperacingtrans.com/?product=crt-billet-trans-brake-1st-2nd-gear-launch
Anyone here using this?
Anyone here using this?
Cope 2nd gear leave valve body
- Thread starter Hemirunner
- Start date
That’s interesting.. I know that’s part of the reason glides got popular in mopar is at the light you’ll blow them out upon launch.. 1st is too steep and I guess this copes approach to it... seems like a good idea..
Hemirunner
Well-Known Member
It’s been a thing in TH400s for years to lower the SLR in order to calm the car down. I’m at 9.48 SLR.
My theory is us at much SLR as you can tune the syspension to. Many give up and go to low SLR and big tires. I've been pretty succesful running 10.53 SLR on 10.5" bracket and index racing. The car doesnt have huge power. But it has more than the average no box car.
Doug
Doug
Hemirunner
Well-Known Member
That’s our current plan right now as the car is already together. We do have the luxury of launching with little to no boost and tuning power into it down track. It’ll probably be 1000rwhp or so starting out and working up to 1500 or so.
We do the same. Dial the timing, boost, and leave rpm. Since ours is blow thru carb there is no adjustment there. Once you get it set, it works very well. way more mild than yours. Normal is 4000
rpm, 12lbs at the hit on 275 Sportsman Pros 1.38 60 @3775lbs 3.55 gear
Doug
Dodge 330
Well-Known Member
I run a 3.54 rear gear and hit the full 200 shot of nitrous off the line. We have run a best 1.37 60 ft. on 275 ET Street Pro's. I do use the 2nd gear start in the mvb on the street and unprepped racing. It seems to work fine for that.
Hemirunner
Well-Known Member
The output shaft doesn’t like the second gear shift with the tight converter. Ordered a new converter and this valve body. It should be interesting...
440rb
Well-Known Member
The guy I helped last year with the big ci wedge RR, has an 11.3 SLR, with 4.10's/a low 1st gear 727 w/big torque on a small 10" hoosier@16psi, caltracs/mono's 9ways on 7 stiff, it hooks real good best is a 1.42 60@3800lbs but its not consistent in the 60's 1.42>1.52 cos of drivers inability to do the same routine everytime and even know what he's doing right and then wrong, as a brkt racer thats death.
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Hemirunner
Well-Known Member
I think the power level needs to be taken into consideration here. I’m going 1.46 60’ at 3950lbs leaving at low rpm on no boost and ramping it to 8psi. We which is maybe 1000 wheel horsepower ... we want to launch at 8psi and ramp to 20ish.
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Mike Gaines
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What is SLR ?
Hemirunner
Well-Known Member
Starting line ratio. 1st gear ratio x rear gear ratio. 3.73 x 2.54 = 9.47 for me. SLR in 2nd gear will be 3.73 x 1.54 = 5.74
Consistency with 10.53 SLR. Last time out 10.5 tire, foot brake with starting rpm set by tach (no starting chip), no air shift. Runs #2 /#6 60 ft was with the rear tire. Run #1 throttle was set at 3/4 open to test 9.25 index run. Last passes the engine was wounded and fell off .02 then .05
Doug
Doug
Hemirunner
Well-Known Member
Very nice. What software are you using for that data?
Crew Chief Pro. Altronics has weather data.
Doug
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