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Title: Swing axle - Drag Transmissions - Gears ratios choices Post by: julienvwspirit on November 17, 2011, 17:13:18 pm Hi folks,
I need your help regarding a strip/drag race gears choice. Since 4 years, I use my 1960 Beetle on Drag-strip. Right now I use a 2332cc, 212HP engine with a Rancho Pro-comp plus*. I have actually 2 different offers from US' builders for 2012 updates (current transmission meet some troubles with differential when is use M&H slicks). I use for calculations street tire width like 205 / 70 / 15. I don't want to use a spool, Quaife was planed. In Strip I use 6 / 26 / 15 - M&H slicks. Max 7'500 RPM (limiter), I shift @ 7'000 RPM usually *Actual gears are : 3.88 RP (3.875) 3.78 2.06 1.58 1.21 ---------------------------------------------- I plan to use (after recommendations with approx 1800 lbs) 3.88 RP 4.13 2.46 1.71 1.30 (all from Weddle) or 1.32 from an other brand What do you think about that and can you give me some feedbacks ? In fact, how you choose (experience, program, sheet) accurately 1-4 gears according to the power (hp) and weight of the car ? Best regards and thank's in advance to help a "beginner". Julien Title: Re: Swing axle - Drag Transmissions - Gears ratios choices Post by: BeetleBug on November 17, 2011, 18:10:36 pm Race car?
Street car? Weekend warrior? Street/race car? Weight? Torque curve/hp curve If race car I can't figure out why not use a spool. It's strong, safe and light. A heavy car would benefit from box #2 but it will be a pain on the road with a 1.30 4th. In the end it all depends on what you want to achieve. -BB- Title: Re: Swing axle - Drag Transmissions - Gears ratios choices Post by: Udo on November 17, 2011, 19:15:56 pm 3.88 RP
4.13 2.46 1.71 1.30 (all from Weddle) or 1.32 from an other brand For racing it is ok but on the street it is too short . Or you get some bigger tires for street use :-) Udo Title: Re: Swing axle - Drag Transmissions - Gears ratios choices Post by: TexasTom on November 17, 2011, 19:58:58 pm Check out this link ... it has a couple calculators for transmission gearing.
Fun to play with ... ;) TxT Title: Re: Swing axle - Drag Transmissions - Gears ratios choices Post by: julienvwspirit on November 18, 2011, 08:11:27 am Check out this link ... it has a couple calculators for transmission gearing. Fun to play with ... ;) TxT Thank you TxT But I don't see your link ;) Title: Re: Swing axle - Drag Transmissions - Gears ratios choices Post by: mick on November 18, 2011, 08:27:56 am try this one
http://vexer.com/automotive-tools/speed-rpm-calculator mick Title: Re: Swing axle - Drag Transmissions - Gears ratios choices Post by: julienvwspirit on November 18, 2011, 08:34:07 am Race car? Street car? Weekend warrior? Street/race car? Weight? Torque curve/hp curve If race car I can't figure out why not use a spool. It's strong, safe and light. A heavy car would benefit from box #2 but it will be a pain on the road with a 1.30 4th. In the end it all depends on what you want to achieve. -BB- Thank you for your quick answer, weight is written in my previous post, approx 1'800 lbs or 820 Kg (with me). Very hard to define the final destination of the car, I don't use anymore the car on the street with this 2332 engine. Serious gearbox is expensive and I search a good compromise like "Street/race car" if in the future I put a smallest engine... It is a idea or go for no compromise and put a pure race gearbox with my 2332cc. Udo was right ;D ! (http://www.vwspirit.ch/upload_membre/albums/userpics/10011/2332_dyno_julio_se11.jpg) (http://www.vwspirit.ch/upload_membre/albums/userpics/10011/dyno_1_julien.jpg) Here is the HP curve, please consider blue line 1 (we have made lot of IDA's jetting tests on the same sheet). Thank you for your help, it is appreciate. Julien Title: Re: Swing axle - Drag Transmissions - Gears ratios choices Post by: julienvwspirit on November 18, 2011, 08:36:45 am 3.88 RP 4.13 2.46 1.71 1.30 (all from Weddle) or 1.32 from an other brand For racing it is ok but on the street it is too short . Or you get some bigger tires for street use :-) Udo Thank you Udo for your feedback and experience. Title: Re: Swing axle - Drag Transmissions - Gears ratios choices Post by: julienvwspirit on November 18, 2011, 08:37:53 am try this one http://vexer.com/automotive-tools/speed-rpm-calculator mick Amazing !!! Thanks ! Title: Re: Swing axle - Drag Transmissions - Gears ratios choices Post by: TexasTom on November 18, 2011, 17:40:55 pm Oops! Here we go ...
http://2.3liter.com/Calc1.htm ::) Title: Re: Swing axle - Drag Transmissions - Gears ratios choices Post by: Udo on November 18, 2011, 18:19:46 pm Race car? Street car? Weekend warrior? Street/race car? Weight? Torque curve/hp curve If race car I can't figure out why not use a spool. It's strong, safe and light. A heavy car would benefit from box #2 but it will be a pain on the road with a 1.30 4th. In the end it all depends on what you want to achieve. -BB- Thank you for your quick answer, weight is written in my previous post, approx 1'800 lbs or 820 Kg (with me). Very hard to define the final destination of the car, I don't use anymore the car on the street with this 2332 engine. Serious gearbox is expensive and I search a good compromise like "Street/race car" if in the future I put a smallest engine... It is a idea or go for no compromise and put a pure race gearbox with my 2332cc. Udo was right ;D ! (http://www.vwspirit.ch/upload_membre/albums/userpics/10011/2332_dyno_julio_se11.jpg) (http://www.vwspirit.ch/upload_membre/albums/userpics/10011/dyno_1_julien.jpg) Here is the HP curve, please consider blue line 1 (we have made lot of IDA's jetting tests on the same sheet). Thank you for your help, it is appreciate. Julien When i see this diagraph may be you get some problems in the topend . You need some more rpm's . but try it out and if not you must do some work on the engine :) Udo |