Typical FE Dyno and Standard Gear Charts

[Erik Skirmants]

One of the most common requests is for us to share typical dyno and the gear charts with the community:

Typical Dyno Curve:

http://sccaenterprises.com/tech%20bu...yno%20Perf.pdf

the 00's are missing from the RPM's. Don't get too hung up on the HP numbers, correction factors / altitude etc have an effect and we are not out to impress anyone. Our dyno is (according to Super Flow) being used with as much accuracy and repeatablity is any customer they have ever had...day to day matters...big numbers do not.

Gear "Sawtooth" chart:

http://sccaenterprises.com/tech%20bu...FE%20Gears.pdf

Pick your shift point (see dyno graph ) and draw the shift point drop down lines in to complete your sawtooth...(note the drop 3-4...hint hint...)

[iamuwere]

Thanks Eric. That is a big help to me right now.

Thanks to your time for working so tirelessly to keep the playing field even.



jim

[Eric Cruz]

Amazing how the torque and power curves always seem to cross at 5250... Thanks, Erik!

Best regards,
Eric

[Erik Skirmants]

Amazing coincidence...it does for the SRF too!!! WOW...buy a lottery ticket...wait...BSME from Michigan State...wait...it's almost back...now I remember!!!

Power (hp) = Torque (ft-lb) * RPM / 5252

[John Robinson II]

Ok, here is a question for you edumacated racers...should the shift point be where you drop down to the highest (or just below it) point on the torque curve, or is HP more important then torque for achieving top speed in the quickest possible time?

John

[Billy Wight]

Ok, here is a question for you edumacated racers...should the shift point be where you drop down to the highest (or just below it) point on the torque curve, or is HP more important then torque for achieving top speed in the quickest possible time?

John

John,

The best way to do this is by creating a spreadsheet that calculates road thrust. You can do this by taking the torque curve, gear ratios, and various other parameters (tyre diameter, primary engine reduction, etc). Your shift points will be where the lines cross for each gear. In the example below the lines don't cross so you will want to shift at redline for this particular setup (this is a DSR). You can get extra fancy and incorporate a Cd and frontal area like the example below for net road thrust that accounts for aero effects too...

[iamuwere]

Ok, here is a question for you edumacated racers...should the shift point be where you drop down to the highest (or just below it) point on the torque curve, or is HP more important then torque for achieving top speed in the quickest possible time?

John

I am vaguely amazed that someone as fast as you could have questions about cars still. It makes me think I have no hope sometimes!

jim

[Jim Christian]

Or you could just use the data from your Data system and skip doing all the calculations, and estimates.
Jim C.

[Marshall Mauney]

Gear "Sawtooth" chart:

http://sccaenterprises.com/tech%20bu...FE%20Gears.pdf

Erik -

Any chance of getting this chart updated to show the new 4th gear....?

MM

[SStadel]

The new gear chart should look something like this.

[iamuwere]

Steve, sure that is right? It has the lines in the right places now!

[La Scuderia Raggi]

Hmmm, the chart has a listing for "6th" gear. Get the rumor mills running!