Reaction time question

[Mike Rietow]

Going with a car from track with a .370 Pro Tree we are double O's on, to a track with a .400 Pro Tree. Both tracks are Compulink.

How much will 9" of additional rollout on the front tires pad reaction time ballpark figure? We can't adjust the chip lower because it's a radial tire car we're gonna race at Lights Out SGMP in the new DXP class. The car has a fast Pro Tree transmission brake in which I could replace with a slow bracket brake I have, however I'd prefer the potential for positive ET gain of the additional rollout going from a 26" 82 rollout to 29 91 rollout with other sizes/options in between. I'm also curious a ballpark figure how much in positive ET gain there is potentially with the additional 9" of rollout 5.0's 136 mph 1/8 mile staged shallow.

I figured nobody could answer these types of questions better, more accurately than Stock and Super Stock racers. Thank you ahead of time for any input. We gotta get some front runners to accomplish this, not exactly sure which to go with.

[Jeff Stout]

From 26 to 29 tire your starting line rollout is only 3/4 inch with a 1.6 inch beam off of ground. Im GUESSING about .015 slower reaction time.

[Mike Gray]

n/m

[Mike Rietow]

Originally Posted by Jeff Stout

From 26 to 29 tire your starting line rollout is only 3/4 inch with a 1.6 inch beam off of ground. Im GUESSING about .015 slower reaction time.

Sounds about right, Thanks for the common sense approach of looking at it. I'm wondering why I didn't think of that!

I think there's gonna be quite a few red lights in this class or tight RT racing at the very least. Good to know we have a ballpark of around 015 to work with. Slow trans brake gonna see some duty, see how it ends up.

Thank you

[Jeff Stout]

My bracket car I have 2 brake buttons. The Duran button is the slowest reacting. I need it for full tree racing. It's about.25 slower then my instant button.

[Myron Piatek]

A little tire pressure drop couldn't hurt, if you have enough of a margin to work with safely.

Moroso has a 29.2". Watch your front fender clearances.

[Mike Rietow]

Excellent idea's I appreciate it. I've tested a few buttons I have so I'll be pulling those out as well as another option.

We were looking at the Moroso drag special 29 as a possibility, hadn't considered fender well clearance, thanks!

The deal with this class is it's new, uncharted. It's an all small block class limited to 2850 lbs through 3100 lbs depending on what small block cylinder head you run / no wheel bar allowed. 275 dot radial and a cheater plate,,,, 300hp is all the plate will do unmodified. Track officials hand you an unmodified cheater plate, you put it on and they put a seal on it.

I get to thinking we can leave on 300 hp or close to it, without using much of the controller to manage wheelstands / tire spin . The obstacle is gonna be not turning on the red light. I can see race's coming down to who does this best. We definitely don't want the programmer / controller to act as a delay box managing RT's, while negatively affecting et's.

Lots of good idea's thanks again.

[Mike Jones]

Mike,
Hope you spend wisely.
Like me, looks like you could use a new camera
Good Luck
Merry Christmas
Mike A114

[Jeff Stout]

Why will the cheater plate only flow 300? Is it due to amount of holes in spray bar or does it have a permanent jet in it? Also what ET to run in this class?

[Mike Rietow]

Originally Posted by Jeff Stout

Why will the cheater plate only flow 300? Is it due to amount of holes in spray bar or does it have a permanent jet in it? Also what ET to run in this class?

300 is all the plate will due to the number of holes is exactly right. In other words your question is posed exactly correct, no matter what jet is put in the plate, it'll only do 300.

Track officials pass out plates, in exchange for your plate. Putting a seal on once the exchange / install happens leaving no chance of cheating plate rule.

We've been 5.19 131 with a lesser caliber 23 sbc (Brodix Track 1 227) probably around 1050hp, 700 lift cam

Our new powerplant will put us up around 1150hp with the camshaft approaching an inch of lift. 875 + 300. 3.875 x 4.185 427 sbc 23 All Pro raised runner. 66 Chevy ll that looks factory all steel fiberglass hood 2950lbs.

5.0's would be my guess up front.