15 S550 Boosted Re-Gear options?

[Nathan5150]

Hey Guys,

I have a 2015 Mustang Gt with the 6m MT82 Trans

So I have been driving this car Mainly for Drag Racing, I occasionally do some local cruising with minimal hwy but some roll racing as well.
I have been fighting Launches at the track car seems to bog fall flat then pick up so 60ft has been horrid
Best run at 4800ft Altitude here in Colorado was a 12.2 @125mph thats holding a 2.2 60ft launching anywhere from 4500-5500 rpms and dumping the clutch.
This car hooks great but the launch can be improved both by Driver and playing with the RPMS some more

I recently took the car out this weekend and tried a 5500 launch and blew the rear diff, I currently have the 3.55s gearing from factory and am looking to rebuild the diff this off season.

What gearing should I go with?
I have searched and searched for hours and can never find a real answer every setup is different!
I've looked at 4.11s, 3.31s, 3.15s etc currently the car seems to be a back half car right now but I know there's more mph in this thing at 1/4 mile. Is there any good options to go with both gearing, replacing the spool/pumpkin and getting a better experience in general?

Here are the current mods:

• Paxton 2200sl ( 3.33 Pulley 6rib )
• Lethal Performance lvl 2 Return fuel system
• 18+ Manifold
• Catless Long tube Headers
• 2000hp DSS Rear Axles
• DSS Aluminum Drive Shaft
• Steeda Rear Stop the Hop Ultimate Kit
• Weld Laguna 18in front wheels
• Weld Laguna 18in Read wheels with beadlocks
• Mantic Clutch with braided lines, flywheel etc 26spline
• Stage 3 Ben Calimer Transmission with the following gearing
• 1st 3.46
  2nd 2.29
  3rd 1.61
  4th 1.26
  5th 1.0
  6th .61
• Rear tire Hoosier D06 28X10 18
• N2MD Wot Box
• MGW Short Shifter
• Upgraded Oil Pump gears and CS
• Upgraded BOV and BPV have 15lb spring
• Currently tuned on e85 by Rob Schoemaker

Anyone out there with a similar setup trans included that has switched up the gears ??

Thanks in advance!

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[Unbridled5.0]

The best gear for the track is seldom the best gear for the street. You need to decide which is more important. It's unclear from your post which is the priority.

But, the idea for drag racing is to cross the line while making peak hp. What gear/rpm are you crossing at now? Do you need to use a 28" tire? It sort of sounds like you could step over to a 26" which should help the bog, and give you some more rpm too.

 

[Nathan5150]

The best gear for the track is seldom the best gear for the street. You need to decide which is more important. It's unclear from your post which is the priority.

But, the idea for drag racing is to cross the line while making peak hp. What gear/rpm are you crossing at now? Do you need to use a 28" tire? It sort of sounds like you could step over to a 26" which should help the bog, and give you some more rpm too.

Thanks for the response I’m more concerned with track time vs daily driving.
I run a 28 after switching from Mickey Thompson ET streets they were a 305/40R18 I had traction issues but they were a radial vs a slick. Wasn’t many options at the time for a slick having 18in wheels so I decided on the 28x10 Hoosier.
I usually hit the 1/4 shifting out of 4th and into 5th that’s shifting at about 7-7500rpms.

 

[robvas]

3.73

Why the heck do you have a 15lb spring in the BOV?

 

[robvas]

Do you need to use a 28" tire? It sort of sounds like you could step over to a 26" which should help the bog, and give you some more rpm too.

3.73 and 28" is about the same as 3.55 and 26", but you get to stick with the bigger tire for more grip

You could even go to a 4.09 but 1st gear would be super short. Maybe launch it in 2nd

 

[Unbridled5.0]

Thanks for the response I’m more concerned with track time vs daily driving.
I run a 28 after switching from Mickey Thompson ET streets they were a 305/40R18 I had traction issues but they were a radial vs a slick. Wasn’t many options at the time for a slick having 18in wheels so I decided on the 28x10 Hoosier.
I usually hit the 1/4 shifting out of 4th and into 5th that’s shifting at about 7-7500rpms.

I think part of the problem is trying to be serious about drag racing while using an 18" wheel. That's aiming more for the street. I would start looking at 15's and a 26" slick. Play with gears if you need to after you see where that gets you.

 

[Unbridled5.0]

3.73 and 28" is about the same as 3.55 and 26", but you get to stick with the bigger tire for more grip

You could even go to a 4.09 but 1st gear would be super short. Maybe launch it in 2nd

He's not having grip problems. He's bogging right now. Bigger tires are heavier and if they're not needed, then it's moot. 1k hp+ cars use 28's with more success than lower powered cars. If he steps to a 15" wheel and a 26" tire, he'll already have more sidewall for bite and halfshaft protection than he does now, with less weight and more rpm. It's all testing, but that's where I'd start. Someone here with more experience with these cars will step in I'm sure..

 

[robvas]

He's not having grip problems. He's bogging right now. Bigger tires are heavier and if they're not needed, then it's moot. 1k hp+ cars use 28's with more success than lower powered cars. If he steps to a 15" wheel and a 26" tire, he'll already have more sidewall for bite and halfshaft protection than he does now, with less weight and more rpm. It's all testing, but that's where I'd start. Someone here with more experience with these cars will step in I'm sure..

I suggested a little more gear but wouldn't go back down to a 26". Plenty of guys run 28" with less power

If he's bogging when supercharged with an MT-82 he needs to launch it differently

 

[Unbridled5.0]

I suggested a little more gear but wouldn't go back down to a 26". Plenty of guys run 28" with less power

If he's bogging when supercharged with an MT-82 he needs to launch it differently

Yea...perhaps...and perhaps he needs a different wheel/tire that's sized correctly for his car and goals too.

Plenty of people run 26's with more power than him. Why? Because the lightest stuff to get the job done is better for racing. If the guys who have to run 28's could get it done on 26's, they would. And they'd be faster for doing it.

 

[K4fxd]

If I read OP correctly he needs a gear because he broke the one in the car.

I would pick a gear like 4th and get the rear gear and tire to run 130 at 7000 RPM.

If I thought 125 was all i could run get I'd gear for 125 at 7K

I like 28 inch tires because they will hook better on bad surfaces.

 

[Nathan5150]

3.73

Why the heck do you have a 15lb spring in the BOV?

Was told by the Rob to throw it in there to hold more boost it’s on my torque booster side.
For your other response I thought about going higher in ratio but I know it would eat through first fast I could no lift shift it into 2nd pretty quick so could help. I agree with your tire response I went 28 to help with grip and it does help having them for sure.
What’s your thoughts on gearing Down? Probably not the best idea?

 

[djcodeman]

3.31
You should be hitting the traps at the top of 4th and not have to shift into 5th.
Also why not ease into the accelerator off the line to prevent bogging.

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