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Cal-look/High Performance => Pure racing => Topic started by: Rodger jeska on March 25, 2022, 01:00:33 am



Title: 1/8 mile transmission gearing verses 1/4 gearing.
Post by: Rodger jeska on March 25, 2022, 01:00:33 am
Please school me here. I'm listening... I'm building a drag bug truck modestly wanting to turn 13s maybe on a good day break into the 12's in a quarter mile hopefully a little over a hundred miles an hour. Currently have a 388 rancho super Street 89 fourth. I will either be running a 24-in tire or a 27-in slick. Hopefully I will be 150 horsepower at the wheels. My current combo is only 125 but I will be adding some compression and 48 ida's... i pie cut frame head and raise torsion housing about 2 and 1/2 in... I'm IRS. Thank you

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Title: Re: 1/8 mile transmission gearing verses 1/4 gearing.
Post by: PPRMicke on March 27, 2022, 09:01:59 am
Please school me here. I'm listening... I'm building a drag bug truck modestly wanting to turn 13s maybe on a good day break into the 12's in a quarter mile hopefully a little over a hundred miles an hour. Currently have a 388 rancho super Street 89 fourth. I will either be running a 24-in tire or a 27-in slick. Hopefully I will be 150 horsepower at the wheels. My current combo is only 125 but I will be adding some compression and 48 ida's... i pie cut frame head and raise torsion housing about 2 and 1/2 in... I'm IRS. Thank you

Sent from my moto z4 using Tapatalk



I would choose the 24 "tires
But not to be stupid towards you Why choose 3.88i R&P
If you were to build a new box for the strip R&P 4.37 / 4.13 1- 3.89 2- 2.25 3- 1.52 4- 1.13 26 "6" Wide The start is the most important thing to get off on an engine weak car PS heavy flywheel and heavy pulley so get man to 60 feet


Title: Re: 1/8 mile transmission gearing verses 1/4 gearing.
Post by: Rodger jeska on April 05, 2024, 19:40:56 pm
Okay I ended up with 26 inch slicks. Just purchased some close ratio 3rd and fourth gears hopefully get them put in this month. 1.56 and 1.17. But the real question I have is about rear alignment. I have 1/16 inch toe out. Question please answer. My rear camber is + 1 on left side and +2.25 on the right side is this acceptable. I went through the trouble to flip my control arms and narrow them almost 1 inch to getvrid of negative camber I also installed 28 mm torsion bars and adjustable spring plates. Everything is coming along nicely. I also built a clutch management device for clutch pedal.[attachment=1][attachment=1]


Title: Re: 1/8 mile transmission gearing verses 1/4 gearing.
Post by: ibg on April 07, 2024, 05:53:25 am
I really like your car, who makes those front wheels?  8)
Up front, I race circuits not drag so not the same situation, but the adjustment methods are the same. I'd try to get your camber to 0 degrees and much closer on each side. If you have gone as far as you can go with the spring plate camber adjustment, you need a more radical solution. Over time a few people have made offset/eccentric inner IRS pivot bolts and a pair of these should let you dial in the camber. For the toe out problem, put the big washers on the outside side of the pivot bolt?  I like to run a touch of toe in, though for drag I think 0" should be good, as when you launch the pressure on the spring plate bushes will probably give you a touch of toe in. I find toe out makes the car 'twitchy'.
there is a fair bit of info here on setting camber using the 'smile - frown' method, moving the inner pivot box and eccentric pivot bolts:
https://www.thesamba.com/vw//forum/viewtopic.php?p=9748806
Good Luck and keep up the great work


Title: Re: 1/8 mile transmission gearing verses 1/4 gearing.
Post by: mikko k on April 07, 2024, 10:20:20 am
But the real question I have is about rear alignment. I have 1/16 inch toe out.

Toe out in rear is bad. Get toe in, about same 1/16".


Title: Re: 1/8 mile transmission gearing verses 1/4 gearing.
Post by: Rodger jeska on May 06, 2024, 19:46:25 pm
Okay transmission is done I now have 4:11 close ratio gear box.