Gears for Supercharged M6?

[489HotelFoxtrot]

Just got finished with the first stage of the build. Going to run my SS M6 NA this year to put a few more miles on and see if I can come close to the list guys. I'd like to re-gear but have to compromise since I don't want to do it twice. I'd love to go 3.91 but also thinking about 3.73. Dilemma is this fall/winter the engine comes out and gets the 416 kit put in and going FI. What is everyone here in the FI group, running for gear @700-750 rwhp?

[cc-rider]

Are your goals best quarter mile? If I'm reading right into your post...you said "list" guys so I'm assuming that 1/4 mile is your deal. If that's the case...then you might want to think about the opposite direction. If you plan for 700+ rwhp...then you should think about a ZL1 diff and 3.23 gears. The stock SS diff won't handle that power for too long unless you're lucky. And if you plan to use the stock diff...get the Eaton Trutrac locker installed. Some have had good luck there.

But hearing what your future plans are...i would highly suggest finding a ZL1 3.23 diff and doing it right once. Have a look in the driveline sub-forum here. Ton of info.

[Dwright]

Originally Posted by cc-rider

Are your goals best quarter mile? If I'm reading right into your post...you said "list" guys so I'm assuming that 1/4 mile is your deal. If that's the case...then you might want to think about the opposite direction. If you plan for 700+ rwhp...then you should think about a ZL1 diff and 3.23 gears. The stock SS diff won't handle that power for too long unless you're lucky. And if you plan to use the stock diff...get the Eaton Trutrac locker installed. Some have had good luck there.

But hearing what your future plans are...i would highly suggest finding a ZL1 3.23 diff and doing it right once. Have a look in the driveline sub-forum here. Ton of info.

I just finished my build and will tell you on forced induction 3:91 aren't the way to go. It's fun has hell but I don't think I will ever get it to hook. You would be spinning all the way down the track. At this point I don't even think drag radials will cure it. It would help but. After first hand experience I can't see 3:91 under fi working very well

[dreksnot]

I've used and seen 3.73 that have worked well with FI and a good DR or slick for that power level. Amble suspension work is also necessary to get-the-grab off the line, as well as a good drag alignment. Not as simple as a gearing change (but that would help).

[489HotelFoxtrot]

So pretty much same advise as what Cam Motion had said. Stay 3.45 for FI. I was considering the gear change because right now, running NA, its a bit of a dog out of the dig. Power doesn't come in until well after 3000. I was just trying to see if I could compromise a good gear that would suit the car now and still work good with the future FI plans. Also on the weak rear diff comment, I was planning to do the JRE posi mod as well as the billet caps. I am ordering the carbon fiber DS and will have the DSS axles under it. Hoping it will take the abuse

[cc-rider]

Originally Posted by 489HotelFoxtrot

So pretty much same advise as what Cam Motion had said. Stay 3.45 for FI. I was considering the gear change because right now, running NA, its a bit of a dog out of the dig. Power doesn't come in until well after 3000. I was just trying to see if I could compromise a good gear that would suit the car now and still work good with the future FI plans. Also on the weak rear diff comment, I was planning to do the JRE posi mod as well as the billet caps. I am ordering the carbon fiber DS and will have the DSS axles under it. Hoping it will take the abuse

The stock diff had a much much higher chance of failure to it at those power levels no matter what you do to it. JRE mod, Trutrac, billet caps...they all help, but that diff just was never designed to take big power drag strip punishment.

The ZL1 diff was. And has been proven to do so. And the cost of putting in the ZL1 kit is as cost effective as any other option out there. I'll say it one more time...go for the ZL1 diff and be done with it.

[dreksnot]

Too bad you're not closer - I have a 3.73 ZL1 differential that's available. But shipping is beyond killer.

[redirish]

Originally Posted by dreksnot

I've used and seen 3.73 that have worked well with FI and a good DR or slick for that power level. Amble suspension work is also necessary to get-the-grab off the line, as well as a good drag alignment. Not as simple as a gearing change (but that would help).

Can you give the specs for what would be considered a good drag alignment?

[redirish]

Once I went FI the stock dif was no good, one wheel burn outs, lol Once I got the Zl1 373 with the supporting suspension mods I been it.

[POWERFREAK]

Depends on what type of SC you'll be running. I have 4.10's with a paxton and it's insane. Need to shift out of 1st too quickly when your on it, but it's fun on the street.

Sent from my VS987 using Tapatalk

[10aSSee D]

I have 3.91 gears in my 9 inch, it is fun to drive but you will spin the tires. I'm hoping some Mickey Thompsons drag radials will help.

[dreksnot]

Originally Posted by BMR guy

We are running the same wheel/tire setup and pushing 610 to the rear wheels. It all depends how violent your car launches and how far it squats during launch. A really "squatty" launch will have a lot of negative camber and less tire contact with the track. Running some positive camber, even if it was just .25 degrees would be ideal for a track-only car but handling will suffer on the street.

We have run between 1.54-1.56 60 ft/times 4 different times on 4 separate tracks using -.5 degrees of rear camber. This is just our street setting and I'm sure we are probably seeing some excessive negative camber off the line but on a prepped track we have had zero wheelspin so there has been no need to adjust it any differently....so far

Originally Posted by redirish

Can you give the specs for what would be considered a good drag alignment?

I've tried a balancing act with 0 degrees camber. It is okay for both worlds (street and strip), but not idea for either. -0.5* to -1* would be great for the strip in our heavy IRS cars but your tire wear would suffer on the street.

[MarioSS]

Great thread guys! Thanks for all the info very helpful

Sent from my ONEPLUS A3000 using Tapatalk

[hillshooter]

I am going to be the guy against the grain here. My setup is as follows.

418CI texas speed motor 11:1 compression ration, stage 2 FI cam package, also from texas speed.
Procharger D1SC at 14PSI, methanol injection
kooks long tube headers

Micket thompson ET street II on 18's

Dual tune setup with Ngauge for race gas/pump gas.

Finally I have 3.91 gears and I love them. I have trouble hooking on the street but on the track my best 60' is 1.6 and thats in a 6 speed manual. I am novice at the track and feel my 60 will get better.

I really feel the 3.91 the only way to go and still to this day my favorite mod. I absolutely annihilate first and second gear.

3.91 is good all the way to the low 140's trap speed in 4th gear. If you want 150's or higher then you need more gear.