Rob94hawk

iTrader: (1)

I'm going to leave this one up to the pros. The car is a 1994 LT1 Firehawk, M6, street driven, would like to take it to the track on occasion, and according to recent events my ABS is shot (ABS inop light is on along with Brake and Trac light flashing and I have no intentions on repairing it,) and no traction control. Intend on using drag radials and eventually would like rear suspension upgrades to help get the power to the pavement.

I don't know if power adders are in the future. I only put in a Spec stage 1 clutch.

I keep getting told that even with street tires I now have the potential to break the stock rear end. So what rear and gears do you recommend? Here's one of the dyno graphs to see where the rpms are. If I'm missing any info let me know. Thanx.

82cetuner

iTrader: (9)

if you keep street tires on it you will probably be ok on the rear end for a while, however hard clutch dumps are risky even under stock hp, wheel hop is a true killer.

you can get away with a mild built 12 bolt but the rear end gears has alot to play with the cam size you have and the rpm power range you have as well as tire size height.

I would have to say 4.11s for a M6 though. but remember if you plan to keep your stock rear end and run 4.11s or higher your actually weakening your rear end.

i would suggest a good 9 inch if you can afford it from MWC.

Rob94hawk

iTrader: (1)

Or I could just do this:

http://www.gmhightechperformance.com...l/viewall.html

CRAZZ28

iTrader: (13)

IMO there is really no point in trying to strengthen the 10 bolt. 400+ hp m6 cars just need a better rear. especially if there is any chance at all of putting sticky tires on it. 12 bolt will hold the power but many have problems with gear whine after hard track launches. A moser 9inch with 4.11 gears is the best option IMO

Rob94hawk

iTrader: (1)

I'm sure a 9 incher would be ideal but some of the rears I've seen from Midwest Chassis in a few of these threads look like they cost more than my engine that I just built! Like some of the pics in this thread I was just recently drooling over:

https://ls1tech.com/forums/gears-axl...-new-pics.html

Bob@BruteSpeed

iTrader: (16)

http://shop.brutespeed.com/Moser-9-I...c-Truetrac.htm
Check out the above rear that includes shipping into it's price.

http://shop.brutespeed.com/Brute-Spe...nformation.htm
Info that may help you out.

http://shop.brutespeed.com/Moser-9-I...structions.htm
Moser 9 inch installation instructions

These rears ship out just two days after the order is received. Bob

Valkyn

iTrader: (8)

I went moser stamped 9" with 4.11 gears for my M6 car that I was planning on 400hp NA and a 150 shot.

35 spline axles and a full spool might be overkill but gives you some room to grow.

Rob94hawk

iTrader: (1)

How much power do you lose to the wheels percentage wise by switching to a 9"?

LPE 403

iTrader: (6)

Street car, your power level, little track time, M6? If you're not a gear jammin, clutch dumpin spaz, S60 would be a great choice....too many "9 or nothings" around here .

4.11 in an M6 is nice if like shifting....A LOT....otherwise, shoot for something in around 3.73ish. My $.02....

Valkyn

iTrader: (8)

Everyone around here says 4.11 is like the minimum for an M6...alot of guys running 4.33s or 4.56s.

I would check out the gear calculator and see what your comfortable with, I didn't want to clearance my fenders up to run 28" tires so felt 4.11s were good for me.

I can't comment on how much more power it takes up, there was an article on hotrod.com or something that showed a comparison between a 9" 12 bolt and Dana 60 I'll see if i can find it later.

Also, I forgot to mention that the rear you get also depends on what suspenion stuff you already have. I already had a tq arm and relocation bracket and all that happy crap, but if you dont the Midwest chasis fab'd 9" or Moser M9 are good options since they come with a torque arm and relocation bracket.

MidwestChassis

iTrader: (5)

Our fabricated nine inch package is in the same ball park if not cheaper than any other quality package on the market. That is why it is so popular. It is the only true bolt in after market housing that comes with all needed hardware and out fitted right it will be lighter than a stock 10-bolt. It bolts back in how the 10-bolt came out. No going out to buy your own hardware or beating your floor board to make it fit.

Our package with a spool is $2700 shipped which includes a torque arm and cross member that is lighter than running a stock style bolt in version cross member and torque arm. On top of that we offer unbeatable pricing discounts on other suspension items that can not be beat.



As for your particular gear ration is concerned all depends on what you want from the car. Tire height, rpm shift points all play a huge factor and so does power adders if you plan on adding one later.

LPE 403

iTrader: (6)

^^^ Good looking work in progress situation goin on right there!!

MidwestChassis

iTrader: (5)

I think so as well.

therobman

iTrader: (39)

i put down 390rwhp on that same dyno i live in smithtown and i broke several 10 bolts with just some shitty nitto dr's

Rob94hawk

iTrader: (1)

You still running 10 bolts or did you switch over to something stronger?

HioSSilver

iTrader: (8)

Hey Midwest. How much lighter can you get the 9 over the 10 bolt?

MidwestChassis

iTrader: (5)

All depends how much money you want to spend really. I bet I could get one close to 30-40 pounds lighter but it wouldn't be cheap to do it and some items would be HP limited depending on how light we try to get it. It would also require a spool any other differential on the market will be heavy compared to a spool.

For a lower HP N/A guy we could cut some decent weight out of the rear end and suspension components to give a decent amount of weight savings. especially considering our short arm would weigh less than the brackets you have to use for a stamped style housing.

Rob94hawk

iTrader: (1)

I must have missed your post. Who's running 4.33's and up with an M6 and why? Slicks all the time? Obviously not a daily driver like mine.

I recall an article saying you lose at least 15 hp to the wheels with a 9" but that was a long time ago.

I currently have stock rear suspension so I'm sure I'll get a torque arm with the new rear.

MidwestChassis

iTrader: (5)

The only place you will notice a loss with a different rear end such as a fabricated nine inch like we build is on the dyno. Fifteen HP loss (guesstimated) won't show up in ET but generally being able to launch the car and make a good pass usually results in better ET because most people hold back while they are running a 10-bolt. For good reasons also, with this kind of weight and a manual transmission with C-clips axles is a scarey thought.

82cetuner

iTrader: (9)

what does it matter if you lose a few HP? what good is HP if you cant put it to the ground.

yes a S60 is a cheep choice but they weigh a TON, 12 bolds are a good inbetween on price and strength and you can ususally find them for sale used in the classifieds. I see 3 in there right now.

I chose the MWC 9 cause I needed all new rear suspension compinents anyways and even going to a used 12 bolt would of been just as expensive.

plus I dont mind the extra weight in the back in, since its directly over the tires and it helps my 50/50 weight. our cars are already front heavy so why not add a little to the back and take off weight in the front. plus once I remove the spare tire and jack i bet i will be close to the same weight