Rear End Decisions/Input

[NoDakZ/28]

Alright guys I need some input, and I'm sure this has been asked a few times but here we go. I have been trying to find a Strange S60 with little to no luck, I contacted them yesterday and they are so far out they cant even get me a projected time frame.

Reasoning: End of last summer I went around a corner hard and the ass end slid and I heard a pop. Next thing I know I'm getting a clicking noise in 1st gear low rpm which sounds like its coming from an axle but I have DSS 1400hp axles and they seem ok as far as tightness within the joints, I took the stubs out of the hubs to check teeth and all good. I dropped my oil in the stock diff and zero signs of shavings. I will be sending them into DSS this winter to check. I still have stock 2-piece DS and haven't checked the center support bearing, but was planning on going 1-piece here soon anyways. I also did notice what seems to be a bit more than normal backlash at the differential yolk, so it really could be anything at this point. I don't really see myself going more than 900-1000whp in the near future.

So that leaves me with should I order and wait and hopefully someday get the S60 or just throw a trutrac in my stock diff and a potential rebuild? Our season is pretty much over up north and I have time, I just don't want to be in a bind come next spring. All thoughts much appreciated!

[CamaroCracka]

Upgrading to a Torsen style carrier in your current diff would allow you to keep your current axles without having to change anything. Biggest risk would be going from a dig on a sticky tire. I have a Z28 diff in my vert, but not near your power level. I use a ZL1 diff in the turbo car with Gforce Outlaw axles. I have Outlaws because I broke a ZL1 axle coming off the line with a 10" slick on an 18" wheel. I'm pushing 100 less hp than you are but a touch more torque and I run an LNC 2000 for a two-step retarding 14 degrees. My concern would be, given you have the 1400hp axles, your diff would become the weak link.

[acammer]

Having gone through this for several years - I feel well equipped to give you my two cents.

It all comes down to usage. There are plenty of high horsepower cars out there that run around on street tires and maybe do some highway pulls, but never really do super aggressive launches with big traction. Those cars can survive a long time on the OEM SS parts. But, once you start asking the rear end to make aggressive drag strip launches... it's an when, and not an if it's going to fail.

If you fall into this second category of sticky tires (I see your sig pic!) and hard launches, the OEM 218mm rear end is always going to leave you disappointed, no matter what you do it. I went through several iterations of mine with different gears, the LPW support cover, TruTrac - and it still never had the ability to truly cope long term with the violence even a naturally aspirated stick shift car will dish out when launched aggressively. I've done all kinds of stuff to remove abuse from my launch, and I believe I've done that well, but when you start really asking all you can from it, it will fail you.

So, if that's you, I would save your money and not invest into a rear-end that's not ever going to give you the reliability you want. Take that money saved, and put it into something that will take the power you want to feed it with a smile on it's face. Keep your stock rear end in good condition, and when you sell it along with the axles, it will finance a decent chuck of the S60 or 9" that you end up with. Yes, those (especially the 9") are super pricey options, but for the long term on a car you intend to keep an enjoy without an expiration date, it's worth doing.

Like I said, I've bought, built, or rebuilt - no joke - five iterations of the 218mm rear end. I broke Richmond gears, and I hurt but didn't destroy Motive gears and Yukon gears. I broke a OEM posi unit. I hurt but didn't kill an OEM axle. For what I've spent on 218mm SS rear ends, plus the value of selling the OEM diff, axles, and drive shaft, it would have funded 75% of what a NEW 9" setup costs, and would have completely funded what I have into my current used setup, even with a gear change. I drag race the car regularly, and I wish I had someone talk me into just doing it "right" the first time. Not to mention, my 9" is quieter, and smoother than even a well built OEM diff, and I've got a gear ratio you could never get in the OEM setup.

[NoDakZ/28]

Originally Posted by CamaroCracka

Upgrading to a Torsen style carrier in your current diff would allow you to keep your current axles without having to change anything. Biggest risk would be going from a dig on a sticky tire. I have a Z28 diff in my vert, but not near your power level. I use a ZL1 diff in the turbo car with Gforce Outlaw axles. I have Outlaws because I broke a ZL1 axle coming off the line with a 10" slick on an 18" wheel. I'm pushing 100 less hp than you are but a touch more torque and I run an LNC 2000 for a two-step retarding 14 degrees. My concern would be, given you have the 1400hp axles, your diff would become the weak link.

The S60 is compatible with my DSS axles as well (reason for wanting the 9-3/4"), you just take the diff side spline off. So that's the other reason to go to the S60. I agree on the weak link as well, its taken about 3 years of abuse. Some hard launches on on my 15" setup for a solid 2 years. I only go to the strip maybe 3-4 times a year. Appreciate the input!

Originally Posted by acammer

Having gone through this for several years - I feel well equipped to give you my two cents.

It all comes down to usage. There are plenty of high horsepower cars out there that run around on street tires and maybe do some highway pulls, but never really do super aggressive launches with big traction. Those cars can survive a long time on the OEM SS parts. But, once you start asking the rear end to make aggressive drag strip launches... it's an when, and not an if it's going to fail.

Agreed! its been holding together well for the last 3 years!

If you fall into this second category of sticky tires (I see your sig pic!) and hard launches, the OEM 218mm rear end is always going to leave you disappointed, no matter what you do it. I went through several iterations of mine with different gears, the LPW support cover, TruTrac - and it still never had the ability to truly cope long term with the violence even a naturally aspirated stick shift car will dish out when launched aggressively. I've done all kinds of stuff to remove abuse from my launch, and I believe I've done that well, but when you start really asking all you can from it, it will fail you.

So I pretty much have everything BMR in the rear end, all arms, the bmr drag kit and extreme roll bar. I have been running 15x10 with 275/60 MT ET Street R for 2 of those years on some hard launches. I only go to the strip maybe 3-4 times a year.


So, if that's you, I would save your money and not invest into a rear-end that's not ever going to give you the reliability you want. Take that money saved, and put it into something that will take the power you want to feed it with a smile on it's face. Keep your stock rear end in good condition, and when you sell it along with the axles, it will finance a decent chuck of the S60 or 9" that you end up with. Yes, those (especially the 9") are super pricey options, but for the long term on a car you intend to keep an enjoy without an expiration date, it's worth doing.


Agreed! I just really hope they can catch up or I will be out next season waiting for a S60. DSS has the shaft with the 1350 yolk end in stock, at least that's what they told me a few weeks ago.


Like I said, I've bought, built, or rebuilt - no joke - five iterations of the 218mm rear end. I broke Richmond gears, and I hurt but didn't destroy Motive gears and Yukon gears. I broke a OEM posi unit. I hurt but didn't kill an OEM axle. For what I've spent on 218mm SS rear ends, plus the value of selling the OEM diff, axles, and drive shaft, it would have funded 75% of what a NEW 9" setup costs, and would have completely funded what I have into my current used setup, even with a gear change. I drag race the car regularly, and I wish I had someone talk me into just doing it "right" the first time. Not to mention, my 9" is quieter, and smoother than even a well built OEM diff, and I've got a gear ratio you could never get in the OEM setup.
I think you have made up my mind!

Thank you all!

[acammer]

Originally Posted by NoDak1LE

Thank you all!

Hey - we're to help (you spend your money)!



I think you'll be happy with the S60 or the 9". S60 was my top pick, for more efficiency, but couldn't get the rock crawler gears I wanted for this all motor stuff, and then my used 9" setup just came together for me. My only regret is not doing it sooner.

[Chris49066SS]

Andrew have you got timeslips yet, whats that thing running these days? Awesome setup! (not trying to threadjack, just curious!)

[NoDakZ/28]

Originally Posted by acammer

Hey - we're to help (you spend your money)!



I think you'll be happy with the S60 or the 9". S60 was my top pick, for more efficiency, but couldn't get the rock crawler gears I wanted for this all motor stuff, and then my used 9" setup just came together for me. My only regret is not doing it sooner.

Awesome man! Yeah tbh I love my 3.91's for a turbo car but I am having to shift into 4th at the line so I hope with the 3.73's I can stay in 3rd a little longer.

[acammer]

Originally Posted by Chris49066SS

Andrew have you got timeslips yet, whats that thing running these days? Awesome setup! (not trying to threadjack, just curious!)

Lol (it's laugh or cry) - no slips yet. Finally got it all ready to race, and the fall racing season has fallen apart at my local track. I had the last two Friday's off and fully committed to racing, and the temps/weather got the best of both nights.

Now we're really late in the season and scrambling for places to go that fit in with a busy schedule. Weather looks great tomorrow - all my child care is out of town! Next two weekends are booked both days. I have a few hail Mary's left for this fall coming up the next couple Friday's - hoping to try to find that elusive 10.99 slip.

It should do it. I ran a very conservative launch on the street last week for giggles (2.15 60') and it went a 12.01@123.67 on the draggy, so I think that'll dip into the 10's on a 1.5x 60', and probably run 127 or better out the back. I've got the race weight under 4,000lbs now, more power, and PLENTY of gear and traction, so just gotta put it all together.

[acammer]

Originally Posted by NoDak1LE

Awesome man! Yeah tbh I love my 3.91's for a turbo car but I am having to shift into 4th at the line so I hope with the 3.73's I can stay in 3rd a little longer.

We think very differently - I'd want even more gear, so you can use all of 4th. 4.10s or better. Makes the car a lot easier to 60' as well.

4.10s on a 28" tire would be 6900rpm @ 140mph, 7400rpm @150mph. Plenty to make it out the back with big MPH, helps the car leave with less RPM and slip, and gives you better average power and shift recovery over the run.

3.73 is still only going to go 120mph @7000rpm, which ain't gonna get you anywhere near the traps, and its gonna lay down on that 3-4 shift pretty good. I would hope 800whp would trap in the high 130s to low 140s depending on weight. I'm not sure what RPM you turn, but even 8000rpm is only gonna see 137mph in 3rd.

[NoDakZ/28]

Originally Posted by acammer

We think very differently - I'd want even more gear, so you can use all of 4th. 4.10s or better. Makes the car a lot easier to 60' as well.

To each their own I suppose, ha! My 60' @1.8 for a stick car is pretty decent for now. I called strange again on ETA's and they couldn't tell me anything once again, plus paying for the entire unit up front and waiting on a maybe in the next several months isn't in the cards for me at this time. Hopefully I can find one somewhere or just sell my DSS axles and get a diff/axle/ds setup from gforce.

[dreksnot]

Originally Posted by acammer

We think very differently - I'd want even more gear, so you can use all of 4th. 4.10s or better. Makes the car a lot easier to 60' as well.

4.10s on a 28" tire would be 6900rpm @ 140mph, 7400rpm @150mph. Plenty to make it out the back with big MPH, helps the car leave with less RPM and slip, and gives you better average power and shift recovery over the run.

3.73 is still only going to go 120mph @7000rpm, which ain't gonna get you anywhere near the traps, and its gonna lay down on that 3-4 shift pretty good. I would hope 800whp would trap in the high 130s to low 140s depending on weight. I'm not sure what RPM you turn, but even 8000rpm is only gonna see 137mph in 3rd.

As you know, I've tried all kinds of gearing with my full weight 4,450lbs turbo M6 car [3.23, 3.25 (last), 3.73, 4.11 (current)]. I've tried various RPMs (3,500-5000rpm) to launch, and various boost levels (3psi on 2-step up to 12psi on 2-step & anti-lag). All this does show how my mind works (or doesn't work). To date, I have my best 1.615sec 60ft with a 5,000RPM launch and just 3psi on the 2-step, which also yielded my best 1/4-mile time but not trap speed; needing to say, the track prep was horrendous this day as I spun 7 out of 11 runs. I'm hoping to get traction out of my M/T bias E/T's next time but might have to be next race year. In the past launching 4k RPM I bogged over half the time as I had awesome traction.

What I've learned:
> My heavy Gen 5 needs more RPM to launch
> The 4.11 rear 9" gears have helped a lot over the 3.25. The 3.73 were good though.

> I have the ZL1/1LE transmission gears and I cross the finish line at the top of 4th gear, shift light a'blaring set at 6.7k (actual RPMs are 6,750) - with boost getting me around 905whp per trap speed calculations.
> I will need to spin the motor to 7,300rpm to cross at 150mph (my target) with my 4.11 in 4th gear.
> Setting up a car that I want to do: drag, autocross, daily and Mile is doable, but it's not going to do great at any one of them, but good enough.

[acammer]

Originally Posted by dreksnot

As you know, I've tried all kinds of gearing with my full weight 4,450lbs turbo M6 car [3.23, 3.25 (last), 3.73, 4.11 (current)]. I've tried various RPMs (3,500-5000rpm) to launch, and various boost levels (3psi on 2-step up to 12psi on 2-step & anti-lag). All this does show how my mind works (or doesn't work). To date, I have my best 1.615sec 60ft with a 5,000RPM launch and just 3psi on the 2-step, which also yielded my best 1/4-mile time but not trap speed; needing to say, the track prep was horrendous this day as I spun 7 out of 11 runs. I'm hoping to get traction out of my M/T bias E/T's next time but might have to be next race year. In the past launching 4k RPM I bogged over half the time as I had awesome traction.

What I've learned:
> My heavy Gen 5 needs more RPM to launch
> The 4.11 rear 9" gears have helped a lot over the 3.25. The 3.73 were good though.

> I have the ZL1/1LE transmission gears and I cross the finish line at the top of 4th gear, shift light a'blaring set at 6.7k (actual RPMs are 6,750) - with boost getting me around 905whp per trap speed calculations.
> I will need to spin the motor to 7,300rpm to cross at 150mph (my target) with my 4.11 in 4th gear.
> Setting up a car that I want to do: drag, autocross, daily and Mile is doable, but it's not going to do great at any one of them, but good enough.

We've landed in a similar place with regards to gear... heavy stick cars need all they can get, and lots of RPM (stored energy) off the line to turn into a force multiplier over that half second of clutch slip to get things moving. When you read about or talk to guys that do real serious stick car racing, they talk about start line ratio's in the 15-20:1 range as getting into the place where you want it to be. That's wild - but it matches with everything I've learned doing gear changes in any car I've ever owned - more gear has only ever helped it.

My deal is pretty close to perfect for what I need it to be out the back, and it gives me a 14:1 starting line ratio, which sounds pretty aggressive, but works really well. I wanna make 2 tons go 1.5xx in the 60'. When I look at Draggy data of leaving at like 2500rpm on the street with moderate at best traction, I see peak G's at the top of first gear - which tells me that when this thing hooks from a dig it's gonna pull good G's all the way and really leave like it was rear-ended. At least I hope - it's all theory till it happens. I don't know of anyone that's put this much gear in one of these.

Having a car that 60's hard and can run standing mile is gonna be a struggle, that's just a massive ratio spread that's not really available in any practical way. It would be interesting to talk with guys that do that regularly and successfully to see what they do. Mostly what I see at 1/2 mile and mile stuff is pretty mild/moderate launches and they just feed the power in after they get it rolling.

[NoDakZ/28]

Originally Posted by dreksnot

As you know, I've tried all kinds of gearing with my full weight 4,450lbs turbo M6 car [3.23, 3.25 (last), 3.73, 4.11 (current)]. I've tried various RPMs (3,500-5000rpm) to launch, and various boost levels (3psi on 2-step up to 12psi on 2-step & anti-lag). All this does show how my mind works (or doesn't work). To date, I have my best 1.615sec 60ft with a 5,000RPM launch and just 3psi on the 2-step, which also yielded my best 1/4-mile time but not trap speed; needing to say, the track prep was horrendous this day as I spun 7 out of 11 runs. I'm hoping to get traction out of my M/T bias E/T's next time but might have to be next race year. In the past launching 4k RPM I bogged over half the time as I had awesome traction.

What I've learned:
> My heavy Gen 5 needs more RPM to launch
> The 4.11 rear 9" gears have helped a lot over the 3.25. The 3.73 were good though.

> I have the ZL1/1LE transmission gears and I cross the finish line at the top of 4th gear, shift light a'blaring set at 6.7k (actual RPMs are 6,750) - with boost getting me around 905whp per trap speed calculations.
> I will need to spin the motor to 7,300rpm to cross at 150mph (my target) with my 4.11 in 4th gear.
> Setting up a car that I want to do: drag, autocross, daily and Mile is doable, but it's not going to do great at any one of them, but good enough.

Great info here, we are a lot the same in leaving the line at the same rpm my 2step is also set at 3psi and some timing retard. I spin my motor to 7200 is the only difference. Gearing will sure help, however, now both of you may make me change to a 4.10.

[dreksnot]

Originally Posted by acammer

Having a car that 60's hard and can run standing mile is gonna be a struggle, that's just a massive ratio spread that's not really available in any practical way. It would be interesting to talk with guys that do that regularly and successfully to see what they do. Mostly what I see at 1/2 mile and mile stuff is pretty mild/moderate launches and they just feed the power in after they get it rolling.

Don't have to hard launch the car for the Mile runs. Just get started and roll in to the throttle. Good thing I went with the billet 5th gear in the RPM TR6060 - I'll have to spin the motor 7,400rpm in 5th to hit my 199.9mph target as I have no roll bar installed (rules for up to that speed). And, BTW, since when has practicality have to do anything with racing?