VERY amateur racer here. I have a 440 stroked motor in my 73 scamp. I rebuilt the transmission and put in a Transgo2 shift kit. This year we have only had it out to the track a couple times and allowed the trans to shift automatically. It shifts quickly 1-2-d which may need to be remedied later. We are planning to manually shift in our upcoming races. I have been instructed that the best shift point should be 5800 rpms for this setup. At least start there. My questions are, 1. to shift at 5800, what rpm should I set the tach light? 2. Do you keep the pedal floored during the shift? What are the general concepts to be followed. This is not a bracket race but just Friday test and tune on no prep track. Thanks for any help.
727 shifting in drag race??
- Thread starter Kent mosby
- Start date
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4mulas
Fixem'up
Your shift point depends on your motor, gears, and car set up. No set value for that
keep it floored.
set the light 2-300 rpm early, by the time you react to your light you’ll be at the desired shift point.
you might want to adjust the kick down lever and increase its tension to rectify the early 1-2 shift before driving it much more.
keep it floored.
set the light 2-300 rpm early, by the time you react to your light you’ll be at the desired shift point.
you might want to adjust the kick down lever and increase its tension to rectify the early 1-2 shift before driving it much more.
RockinRobin
Well-Known Member
1. When doing a burnout or actual pass, never let off the gas in 1st gear! You will destroy the overrunning clutch (sprag). You will have to start your burnout in 1st since you don't have a manual valve body, but get into 2nd and 3rd as quickly as you can and do the majority of the burnout in 3rd gear. Don't overrev. 5000rpm in 3rd gear is plenty.
2. Don't burnout in the water. Roll the back tires through the water and then do the burnout. Technique will differ depending on whether you are using a line lock, type of tire, track conditions, etc.
3. Don't downshift after the pass. Let the motor rev down as you apply the brakes.
4. You can start at 5800 rpm as a reference point, then try different rpm both higher and lower to see what the motor/gearing combo likes the best. Above all, have fun!!
4mulas
Fixem'up
Good burnout advise!
Thanks for all the help here. I am familiar with the 1st gear issues. We will avoid that at all costs. When shifting, do you let off the gas or just keep the pedal down? Kind of a dumb question but my manual transmission brain is confused.
pedal down.... manual, unless you are slamming gears would make the engine rpm spike when clutch/shifting, autos shift pretty instant so no need to mess around
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Be sure Kickdown lever is all the way max open at full throttle!
B3422w5
Well-Known Member
I never start a burnout in first gear, always second, been told that is the way to do it forever
RockinRobin
Well-Known Member
I don't think you can start a regular valve body trans in 2nd. It would have to be a manual valve body.
famous bob
mopar misfit
why couldnt a guy do it in drive with a fully automatic trans , would it not shift when the wheels get up to speed >???
RockinRobin
Well-Known Member
Because a fully automatic transmission is going to start in 1st gear from a standing stop. Yes, the valve body will then shift at rpm of its choice.
I'm not sure for your set up but if it is 5800 yes floor it, shift it, never let off until you cross the line. Hopefully you don't have any traction issues.
Since it is test and tune you can dial in where it wants to be shifted, when you're comfortable
The recommendation of 5800rpms was given to me after reading the datalogs from the Super Sniper EFI by Master Engine builder Andy Finkbeiner. He was kind enough to review it on the Holley Forum a while back. Thanks again.
Hopefully the rain holds off this Friday. The last day of the season is Friday October 6th.
Hopefully the rain holds off this Friday. The last day of the season is Friday October 6th.
It sounds like your kickdown linkage needs adjusting correctly. Keep this in mind. You can certainlt shift manually, however, that does not help the throttle pressure at all if the kickdown linkage is not adjusted correctly, so essentially, all you are doing is taking a chance with transmission failure. Without the kickdown right, the throttle pressure is still low and not holding the clutches together very well and you are shifting at over 5k. Not a good scenario.
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I will check this before the races. Thanks a bunch.
Sho nuff!
I hope the rain holds off for you too, because I'll get it 1st & I can warn you !!! Lol
"**** manually" how else, is there some easier way I'm not aware of like automatic **** ? Lol
This is proof that I can read
That is probably correct then.
dammit. lol
Don't they let vaccum pull it out of their buttholes in space? That's kinda automatic, ain't it?
Yikes, I guess you're right
My rule of thumb has always been to shift when the engine is no longer making more power, so, if your engine stops making power at 5800 rpm, that's your shift point. Leaving the shifter in "d" has never been my thing, wring it out and let it eat!
B3422w5
Well-Known Member
May sound ultra old school, but I don’t use a tach for anything other than staging my footbrake car. Same goes with the shift light.
I have found I can be more consistent/ repeatable by shifting the car by feel/ ear, than any other way.
The car tells me exactly where to shift it at. Last outing I ran the exact same number 4 times. The other times the car ran a couple of numbers slower or faster was condition related( cooler early morning or late afternoon) with better or worse DA.
My driving lately has sucked, but I don’t feel at any disadvantage to guys shifting with air or electric or staring at shift lights.
I have found I can be more consistent/ repeatable by shifting the car by feel/ ear, than any other way.
The car tells me exactly where to shift it at. Last outing I ran the exact same number 4 times. The other times the car ran a couple of numbers slower or faster was condition related( cooler early morning or late afternoon) with better or worse DA.
My driving lately has sucked, but I don’t feel at any disadvantage to guys shifting with air or electric or staring at shift lights.
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