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This turbo car is tricky getting down the track, especially no prep stuff. It hooks well off the line and feels soft with a 1.5 60'. The trouble starts about 60ft out, on the shift into 2nd. All the power hits there and usually requires back pedaling to keep from striking the tires. Then once I get past 80-90mph, is manageable for the rest of the run. Roll races starting at 40mph in 2nd are not a problem. I'm running stock suspension, with Hoosier QTP 28x14.5x16.
So I'm wondering about a 2nd gear start. It would eliminate the 1-2 problem. I have nitrous for extra torque off the line. Maybe this gear ratio will work better. A powerglide would be nice, but not in the budget. So what do you think about the ghetto glide technique. Anyone done it?
Drone footage of a typical high boost run with no prep:
I wouldn't start in 2nd. I have seen someone start in 1st and almost immediately shift to 2nd. It worked fairly well at the track. It's similar to short shifting a manual.
I wouldn't start in 2nd. I have seen someone start in 1st and almost immediately shift to 2nd. It worked fairly well at the track. It's similar to short shifting a manual.
I agree change the 1-2 shift point so it won't hit so hard.
This is probably a dumb question, but how do you start in second? Won't choosing that gear only limit the car from shifting into third until moved manually? I thought an auto will always start in first? Please forgive me if this a totally dumb question but I thought I tried it before!
When it's in 2, it starts in 2. The short shift is a good idea too, I'll have to try that. I remember Arun spoke of doing this and pretty sure went like 8.8@160.
When it's in 2, it starts in 2. The short shift is a good idea too, I'll have to try that. I remember Arun spoke of doing this and pretty sure went like 8.8@160.
Well I'm not sure why I thought it didn't work? I was sure I tried it, I have not tried it with my new trans so maybe there was something wrong with my original trans, that didn't allow it?
When it's in 2, it starts in 2. The short shift is a good idea too, I'll have to try that. I remember Arun spoke of doing this and pretty sure went like 8.8@160.
This works like a charm. Launch in 1st and immediately shift to 2nd or D if you don't want to have to worry about remembering or missing the next shift.
I don't think the 4L60 is going to be happy with a 2nd gear launch. I don't know for sure, it's just my gut feeling considering the power you are making. I'm thinking more along the lines of is there enough fluid pressure at that low speed and load to keep the 2nd gear clutches fully engaged and what about the difference between converter speed and input shaft speed? You know more than I do about the internal function of this trans.
When it's in 2, it starts in 2. The short shift is a good idea too, I'll have to try that. I remember Arun spoke of doing this and pretty sure went like 8.8@160.
When it's in 2, it starts in 2. The short shift is a good idea too, I'll have to try that. I remember Arun spoke of doing this and pretty sure went like 8.8@160.
Mine still starts in 1st, even when the shifter is in 2nd. However I am using a PCS controller.
My trans is controlled by the factory PCM. As far as the different gearset option, I never considered it because it's supposedly intended to solve different problems.
1) Improves track applications that overpower the rear tires upon launch.
2) Avoid RPM / power drop-off between first and second gears.
If a powerglide is a viable option, so is a 2nd gear start, as far as gearing goes. I'm curious how much ET is lost during the 1/2 shift, that is eliminated with a 2 speed. Makes sense about abusing the band. It's a $40 part, and seems I rebuild mine on a regular basis anyway.
I heard the trans/TC was modified by RPM to be a 2 speed & each outing the trans broke.
Even after the one hit wonder pass.
Not taking anything away from Arun or RPM, just saying......
Yes, I remember his own words as "specially modified for 2nd gear launch". Exactly what was modified is a mystery. If I got away with it a couple times and it worked good, I might consider a PG conversion.
It's alot, and comparable to a glide conversion. I don't see the benefit of a TH400 here. I think the glide gearing with 1 less shift would help this thing get down the road. The mechanics are weird. In 2nd I can hammer a 40-50 roll and hook pretty well, but a WOT shift into 2nd at 40-50mph and we're dancing. Curious to try short shifting the 1-2 and compare.
You forgot the custom plate between the th400 and the TT.
The TT and prop shaft have to be shortened by 3.5".
The output shaft for the th400 is just a th375 27 spline shaft.
11-12-2015, 10:42 PM
4L60 2nd gear launch?
I was told he did the 2ndd gear launch by mistake 
