AMGSC

Can anyone tell me if the Quaife LSD will allow the gear ratios to be changed by 10-15% in order to get quicker acceleration. I am willing to sacrifice a bit on the top speed as a trade-off. This is similar to a smaller front sprocket mod I made on my motorcycle?

I'm getting the Quaife installed tonight and would like to ask them tommorrow if it's possible or feasible?

AWDman

impossible.

the cheapest way to drop your ratio a bit is by smaller oD tires. ie 245/35-17

MRAMG1

Differentials DO NOT change gear ratios, only a ring and pinion swap will do that. Keep in mind that a very small change, ie 10%, will really NOT be noticed. A gear swap, say from 3:55 to 3:73, will really show little difference.

You need to jump at least 0.50 of a gear ratio to notice a real world change. That being said, you really CAN'T do it with a simple tire change. You will need to drop the overall diameter more than 2" do accomplish this. At that point the car would be dragging on the ground, okay, almost dragging.

See yeah

AWDman

notice i said "a bit" in my post. you haven't stated anything i don't know. there were past posts on this matter.....anyway....i'm going to disagree with you as the 245/35-17 tire is equivalent to putting 5% more torque to the ground. (well in my case with 265/35-19). i may be on 225/40-17 hoosiers this yr for the gearing reduction.

MRAMG1

Okay, calm down for a minute. You are correct that they will make a small difference. Albiet small. There is only one tire, my favorite GS-D3 available in this size by the way. Second, to make a noticable gain, ie at the track drag or road course, you would be hard press to record this change. Jump two gear sizes and the improvement would be HUGE, ie ANYWHERE not just at the track.

PS: Being new here I was not aware that there have been past post, please forgive me.

See yeah

AWDman

no worries mate i'm calm.
toyo t1r http://www.toyo.com/docs/tires/produ...category=sport

sometimes the cumulative effects of many small changes gets one where one wants to be.

"see yah"

AWDman

no worries mate i'm calm.
toyo t1r http://www.toyo.com/docs/tires/produ...category=sport

sometimes the cumulative effects of many small changes gets one where one wants to be.

"see yah"

smgC32

a 10-15% change in final drive gear will be very noticable on acceleration. In some cars this could produce a .50 second advantage in 0-60 times. The tricky part is finding a ring and pinion gear for our cars that is proven to work. It can easily be installed in the Quaife.

AWDman

the c32 amg is already undergeared. it will pull redline in 5th something like 173 mph. the way i see it (for my purposes track days) i think dropping final drive to top out at 160 is optimal. that's like 7% reduction. i'm already pulling 125 stock before braking for big bend at lime rock and that's a relatively short track.

changing ring and pinion will create a host of TC ecu troubles no???? and even if you worked through them you will be stuck with hi revving car at highway speeds.

dropping tire OD on all 4 corners is the easiest and most beneficial way to achieve this end imo. easily reversible, lowered ride height, lowered unsprung weight. the prob is finding suitable sized tires.

last yr about 1/2 the cars for the july 4th grand am race at lime rock were running measly small tires.

past threads i posted explored the possibilities of 16' rims for rear but those will not fit.

....i calculated the c32 gearing, with a 5-6% reduction will be very close to the c63 for 2-5th. the 7gtonic tranny has very tall 6th and 7th gear basically economy.

MRAMG1

Question, why would changing the ring/pinion affect the TC or ECU?
Since this is after the transmission, the engine and TC would simply think you were going faster, ie spinning more revs. Yes your speedo will be off, as I do not know how the AMG picks up this sensor, ie mechanical or electronic, it may be hard to correct this speedo error.

And yes you are correct that for FINE tuning racers have always used tire diameter for SMALL changes. I two have swapped from a 255/45, to a 255/40 for this advantage. And again this sometimes can be VERY hard to find the correct tire/brand.

I can also say that I swapped from a 3:27 to a 3:55 in my road racecar, and saw NO difference on the street. I did notice that I ran out of gear on the back straight away at Nelson ledges and Beaver run as this was a slightly too high of a jump. But no one made a 3:45 gear.

And yes, I agree a 15% swap will make a HUGE difference, using my above gear, ie 3:27, that would mean going to a 3:74. Again approximately a 0.50 gear change.

All I wanted to point out here was that a slightly smaller tire, is not going to show a dramatic difference on the street. Sorry if I ruffle any feathers, I have just simply tried too many low dollar fixes in my day, and ended up with NO difference. Good luck to you on your adventures.

See yeah

AWDman

thanks for the info and input. good to have you on the board. i'm sure we'll be chatting again on various topics.

Fifth Ring

It's awfully hard to get any use out of 5th gear on any track, and in optimal race mode, you would redline in your top gear at the end of the fasted straightaway; and then each gear below that could have the minimum spacing to keep the car it its power band. But MB puts that 5th gear in for economy.

whoover

The ECU/TCU would detect that revs and speed are no longer within expected parameters and throw codes, if not reprogrammed. Things like the adaptive shift programs care how fast you're going in what gear, and the safety systems like BAS, ABS and ESP will all be affected. AMG even makes ECU changes when they install an AMG LSD, and Rob Allan has said that there could be problems with aftermarket LSDs because these changes aren't made. But I've never seen any reports of problems when people add LSDs.

AWDman

those 245/25-17 tires and the shower of sparks are looking better and better.

Fifth Ring

I assume that speed is measured at the front wheels, while revs (duh!) measured at the back wheels. So different diameters would cause misreadings. I assume you would get around that by changing the size of ALL wheel/tire setups.

AWDman

right. the ecu can tolerate up to a certain diff in tire OD. I think smg32 or cyncarver runs 265/40-17 rear with 245/40-17 fronts.

if i wasn't clear before by posting the toyo link the toyo t1r IS made in 245/35-17. so there are 2 tires out there if one wanted to try, like mramg1 stated the diff may be minimal.

AWDman

here's the old thread.
https://mbworld.org/forums/c32-amg-c55-amg-w203/149553-where-can-i-get-shorter-rear-diff.html

AMGSC i had forgotten- MKB does make a lsd with shorter final drive. the tcu has to be sent to germany if reprogramming.
http://www.mkb-power.de/pages_en/pro...&prod_gruppe=3

AWDman

on the c32 i don't consider 5th an economy gear. the car will go faster if it had an even taller final drive. the clk63's 7th gear is good for a theoretical 220+ mph (if i remember my math correctly).

with 400+ hp of a stage 2, plus a 10% reduction then 3rd, 4th, and 5th will be usable. how long is the longest straight at VIR? MrAMG1 how about beaverun?

AMGSC

Thanks! I will inquire with them but I just got my car back from Evosport with the Quaife installed. So is it too late now that I've already gotten the Quaife? An earlier post mentioned something about ring and pinion swap to the Quaife. Where can I get this?

The Quaife makes the car feel much tighter now. The road feel and even the steering wheel feels more responsive now. Am I halucinating? I can still light up my ESP but only for a brief second versus wild blinking/flashing I had before when accelerating hard.

What happens when I install the Kleemann? Would they charge me extra for custom programming because of the Quaife or TCU mod through MKB?

AWDman

yeah too late unless you want to go through the hassle and expense to remove and re install a mkb lsd. also i think the mkb is VERY expensive i have the prices at work. not even sure there's a us dealer.

someone with C55 kleeman knowledge should answer 2nd part of your post....your comments re the lsd sounds positive tho.

MRAMG1

Hello AMDman:

The best straight at Beaver run is the back straight from trun 7 to turn 10. You leave turn 7 at about 55-60 MPH, NEVER lift through turn 8 and 9, and start breaking at about 143 MPH, in my Blown Stang, or about 125 MPH in my M roadster. The straight is about 0.6 Miles long. I haven't had my C32 out yet, as I just got her on thanksgiving, is SNOW here in PA.

MRAMG1

Note: I use Komo race tires, victor series, on the stang, and had Michelins Pilots on the M roadster. Oh yeah, the Pilots STINK!!!! My Yokohama es100 on a 2000 Stang are better than these stinking Pilots on a M!!

smgC32

I run 235 40 18 front and 265 35 18 rear for the street now. 245 40 18 and 275 35 18 for the track. When we ran 225/265 and 235/255, especially when one axle's tires were of a different tread depth, the ecu did strange things and could not accomodate the difference in rolling circumference. ESP was cutting in too much and made the car very unfriendly at the limit.

The Quaife will shine under load while turning. I am sure you now notice how you can make a turn from a stop and accelerate much harder without the power shutting down like before. Good luck with your Quaife experience.

C32AMG/02

[QUOTE=MRAMG1;2036417]Question, why would changing the ring/pinion affect the TC or ECU?
Since this is after the transmission,

Any change in differential ratio will set a gear ratio error code, placing the transmission in limp mode. The only way to correct, coding TCM and ECM with the new ratio.

the101dragons

What was the final cost amgsc?