launching, tq curve,traction

[grumpyvette]

launching, tq curve,traction

 

 

 

now this is in responce to a corvette related question but much of it applies to you gentelmen as well,never reduce the effectiveness of one system to make up for the failure in a second are, maximize BOTH AREAS, and learn to DRIVE in a manor that compensates for the weaker area,EXAMPLE, if you maximize power to the rear wheels and youve done all you can for traction, your driving style can compensate for the differance

 

http://users.erols.com/srweiss/calcmph.htm

 

http://users.erols.com/srweiss/calcrpm.htm

 

http://users.erols.com/srweiss/calcrgr.htm

 

http://users.erols.com/srweiss/transc.htm#Auto

 

these calculators may help a good deal, personally ID sellect the 3.73:1 only because a 3.90:1-4.11 is not available,for the rear without extensive mods,a serious engine will require a matching drive train and stall speed or fly wheel weight and the skill to use both effectively on launcing the car, that generally means a 2800rpm-3500rpm stall speed converter, or a 30 lb-40 lb fly wheel to retail the rpms with zero bogging as you launch,keep in mind youll want the engine rpm band to fall where the engine makes its best power thru the vast majority of its time and you don,t want to be over reving the engine in the lights, ok lets pick a case where you go thru the lights at about 120mph, measure your tire dia. plug in the info and keep in mind that final drive ratio the trans has and your engines realistic peak rpm.

lets assume in this case youve got a 700R4 with its OD top gear 0.7:1 ratio and a 25.5" tire and youll want to be pulling 6000rpm thru the lights at the end of the 1/4

, youll soon see what Im refering to, then look at the same combo at 70mph in OD gear and your rpm range, it should be fairly clear that youll want speeper gear ratios if performance is the main objective, getting traction is a differant part of the equation, but maximizing the available power curve to the rear axle is the first concern, getting it to the pavement requires suspension and tire changes, but it can be done!

don,t let the guys that can,t get traction tell you you need a taller gear, what you need is max power matched to max traction,cutting back on one to ease failures in the other area is counter productive, if you can,t lift the front tires for at least a few feet on launches, traction & suspension mods & better tires not a gear reduction are the problem area

__________________

retired engineer ,engine builder, 1985/92/96 vettes(all modifyied

[Phantom]

Interesting read Grumpy. Makes me feel better about my set-up all the time. With the 3.70:1 LSD and 25-26" diameter tires (225/50-16 or 215/55-16) the 4th gear in my T56 has me right at 6,000 RPM at 120 MPH. A good set of DR's would probably have me running very close to that instead of the current 110 on the street tires.

[grumpyvette]

http://www.staginglight.com/guide/iea.html

 

this may help