Pro Extreme Ratios

Curious what is typical these days in the top ADRL Pro Extreme ranks for rear gear and 1st & 2nd ratios. Doing some simulation modelling and would just like to get a real world sanity check. Thanks for any help.

 

most everyone runs a 5.00 rear gear ....trans ratios vary, alot run 2 speeds....usually around a 1.36 low or in that area......so i have been told.
Darren

 

4.88 to 5.00 and 1.28 to 1.36 first gear is the most common

 

Thanks guys. 2nd gear ratio would be ?......

 

1 to 1, most are 2 speeds, note that many of the cars run a lower gear than has been discussed.

 

gear

Rear 5.00-5.14 1.34 1st to a 1.22 1st all in between.......

 

I assume these are 1/8 mile cars and clutches? or converter?

 

So seeing as we run a 1/4 would it be advisable to stay with a 3spd? or drop to a 2 spd? if staying with a 3 spd what would you suggest ratios should be would i start with the 1.38 or stay lower 1.50 something because of my rear gear ratio which is a 4.56?

 

ratios

I've seen lots of 5.0 and 5.14 rears and as low as 1.41 low with a 36 inch tire.
The low gear ratio can be determined by how fast full timing is applied. Most guys want 10 degrees min. out at the hit for tunability. If all the timing is ramped in by 1.5 seconds the car is not agressive enough so it either needs more power or a numerically higher low gear.
The converter plays a role also where the stator can make it meaner on the bottom.
The numbers I used are examples before the NXS converter. It has changed the values somewhat but basically requires a more aggressive setup early from what i've seen.

 

We run 1/4 only with a converter-driven Pro Mod car and I have tested with a 2 speed and a 3 speed. We made our quickest run ever with a 3 speed (5.75 @ 252) and have run pretty close with the 2 speed (5.79 @ 252). We are consistently a solid 5.80-car. The biggest thing with the 2 speed is the consistency of it. Its much more manageable from track to track. When the track gets hot/greasy, we tend to be able to go down more than most we race with. It has hurt the ET a little bit, and if we run into an issue to where we have to short shift it, it does hurt the performance more than it would with the 3 speed, but thats to be expected. We tried all kinds of ratio changes with the 3 speed and found a combo that we really liked. Havent gone back to it since we started using the 2 speed though, mainly because we were still running well.
I will say this, the taller the better in my book. As long as you can adequately pull it. You find out what works best by testing it and making changes. What someone tells you isnt always best. Look at what the car is telling you. Its always got something to say...

 

Look at what the car is telling you. Its always got something to say...[/QUOTE]



All my car ever says is it wants a new owner...

 

[/QUOTE]All my car ever says is it wants a new owner...[/QUOTE]


LOL! Mine keeps whining that it wants more $$$$......

 

All my car ever says is it wants a new owner...[/QUOTE]

ill sell you another one

 

The PX guys must be pulling some pretty big RPM's then ?..........

 

Hurts the valve springs on our motor just hearing them

Ive heard of some pretty crazy RPM #'s out of the faster cars. Almost not funny. Impressive as hell how quick/fast some of the PX teams are.

 

Out of curiosity, what do you guys turn and what do some of the other deep pocket teams turn?......

 

On a strong run for us, it'll go through the 1320' at 9900-10,000.

 

I'm surprised its that low? Sounds encouraging..... Thanks.