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Just one question, by changing final drive are any other components at risk due to the increased power? Please someone help me understand what this does mechanically.
Just one question, by changing final drive are any other components at risk due to the increased power? Please someone help me understand what this does mechanically.
Tires?
What this would change is how much torque gets put to the pavement. This would be greatest in first gear and would decrease in each of the subsequent gears. Therefore, the greatest stress would likely be from a hard launch. Now given the fact that we already easily break traction on street tires when launching, the actual torque put to the pavement at launch wouldn't change. The big increase in stress would be if you did this in conjunction with drag radials that hook up during a hard launch. In this case, the additional torque to the pavement from the new gearing would be "felt" by everything downstream from the differential. Basically the axles.
Long story short, I don't expect anything would be much worse off mechanically on street tires, but use caution with drag radials. Your tires will burn up quicker if you spin them more. Oh, and your cruising RPMS in 7th gear will go up a bit, so some negligible increases in wear and tear (I wouldn't be concerned about that), and lower highway mpg.
Last edited by BalanBro; May 23, 2018 at 01:57 PM.
What this would change is how much torque gets put to the pavement. This would be greatest in first gear and would decrease in each of the subsequent gears. Therefore, the greatest stress would likely be from a hard launch. Now given the fact that we already easily break traction on street tires when launching, the actual torque put to the pavement at launch wouldn't change. The big increase in stress would be if you did this in conjunction with drag radials that hook up during a hard launch. In this case, the additional torque to the pavement from the new gearing would be "felt" by everything downstream from the differential. Basically the axles.
Long story short, I don't expect anything would be much worse off mechanically on street tires, but use caution with drag radials. Your tires will burn up quicker if you spin them more. Oh, and your cruising RPMS in 7th gear will go up a bit, so some negligible increases in wear and tear (I wouldn't be concerned about that), and lower highway mpg.
Thanks for the answer. Since the final drive gear is at the end of the transmission, basically everything upstream is safe! So on drag radials, some axles may get fried haha
What this would change is how much torque gets put to the pavement. This would be greatest in first gear and would decrease in each of the subsequent gears. Therefore, the greatest stress would likely be from a hard launch. Now given the fact that we already easily break traction on street tires when launching, the actual torque put to the pavement at launch wouldn't change. The big increase in stress would be if you did this in conjunction with drag radials that hook up during a hard launch. In this case, the additional torque to the pavement from the new gearing would be "felt" by everything downstream from the differential. Basically the axles.
Long story short, I don't expect anything would be much worse off mechanically on street tires, but use caution with drag radials. Your tires will burn up quicker if you spin them more. Oh, and your cruising RPMS in 7th gear will go up a bit, so some negligible increases in wear and tear (I wouldn't be concerned about that), and lower highway mpg.
If we concider that, shorter Ratio will causes any generic Effictive, then why MB equipped a shorter Ratio on their unique models like:-
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Hey Celica quick question. For those of us who already have modified TCUs, can you ask your guy if he can guarantee that the coding that’s already been done won’t be written over by this? While you’re at it can you ask him if he has any other trick coding he can do on the TCU? Thanks
I did a quick calculation using an online gearing calculator - there's loads of these online. I've only got 1st to 5th here, but it'll give you an idea at the stock rev limit bud. I got my gear ratios online for the "722.9 MCT" via a google search...apologies in advance if these are incorrect.
Originally Posted by Crya
How does one tune the TCU? Is it like there are only a few specialists that can work the black magic in there or?
Pretty much
Originally Posted by BLKROKT
Hey Celica quick question. For those of us who already have modified TCUs, can you ask your guy if he can guarantee that the coding that’s already been done won’t be written over by this? While you’re at it can you ask him if he has any other trick coding he can do on the TCU? Thanks
I think I already asked him this, but I can double-check with him - I'll shout you when I get the answer. I also already asked if he can do anything else, but he declined and said it's too much of a minefield to get involved with and due to the TCU being a PITA to get in and out, he'd rather he didn't get involved with things like this.
So i've called Eurocharged and Weistec neither one is willing to code the TCU. I called Bren Tuning they asked that I send an email so the tuner can take a look and see if what I want to do is something he can handle. Does anyone know of a shop in the USA that is willing to do this?
BLK, he said it won't overwrite any existing coding that has been performed on your TCU
I just came back from a night drive and it's friggin awesome man. The sad truth of it is that my car is currently probably not that much quicker than a strong FBO C63, but I know where it has come from and it has come on miles from when it was stock.
The low down response and pull at light throttle in 3rd of 4th is so beefy! Full throttle is full of win. Getting off the line is much improved. I sometimes break traction in 2nd in the dry. 3rd gear is a much more aggressive gear in the powerband as it gets to 90. Definitely looking forward to hearing about results from other members when more cars have had this swap carried out
I finally had a chance to get the data logger out and phone timing apps to get some numbers:
40-60 - 1.3s (prev best 1.4)
60-80 - 1.7s (prev best 1.7)
80-100 - 2.5s (prev best 2.8)
60 - 120 - 7.7s
Good improvements from this final drive mod, in addition to the state of tune that the motor is in right now (500whp). I was hoping for a little more help at higher speeds, but alas....the W212 is too heavy to put down some fast times that are comparable to even just an FBO W204. I need to decide if I want to continue and keep the car, or if it's worth bowing out at the top of the cars game
I am very new to this modifying my first mercedes. If I were to put a 3.55 year for the srt8 charger in my car what all would have to be done to the TCU?can anyone help me get in contact with someone who can do it and set up the TCU to play ball. Thanks guys
"After the shop had done the work (new bearings installed of course), it was time to finally fit the 3.06 ring gear and LSD into the Chrysler casing which now has the AMG propshaft flange. Here are some pics of the part numbers of the ring gears - feel free to use these as a reference point."
I, all the sudden had the sinking feeling that I may have bought all the wrong replacement parts for my 2007 E63 differential unnecessarily!!
You then later explain:
"How I did this:
You'll need the 3.06 ring and pinion, either from an old Chrysler SRT8, or from a Mercedes SL63 or SLK55 (I think). Alternatively, you can go to somewhere like Richmond Gear or another vendor that will sell you the gears."
So which is it? Are you taking the Ring & Pinion from the Chrysler 300c SRT8 differential and inserting them into your E63 Diff making certain the Prop Flange from the E63 is newly mounted to the SRT8 Pinion Gear as well as the 3.06 Ring Gear being mounted to your P30 LSD or are you taking the Prop Flange from your E63 as well as your LSD and transferring them into the "Larger" Chrysler differential case and the using that Chrysler Differential's 3.06 Gears with your LSD and somehow attaching it to the subframe Cross Member on your E63? If the latter is the case, then I spent $500 on wrong internals to rebuild my E63 Diff as compared to buying internals specific to the Chrysler SRT8 Diff??
If the latter is the case, is it due to the 3.06 Ring Gear being too big in diameter to fit into the Mercedes E63 Differential Case when mounted to your P30 LSD? Also, does the Chrysler Differential mount perfectly to the front Mercedes E63 Subframe crossmember to which the differential bolts to? I'm tending to think not just from viewing online pictures alone, but some clarification on this subject would be greatly appreciated!
You then list several components that must be purchased to do the swap, one of which was Seals which I had presumed were for the E63 differential case axles, but I may have misunderstood it from the Tranny Pan Gasket Seal?? I've already ordered the Bearings, crush washer for the Pinion, the Seals and protective discs for the E63 Diff so I'm certainly hoping that it is, in fact, the E63 Diff that's being used with SRT8 internals and not the other way around???
Ahhh yes, so the only reason I opened up my AMG diff was because it has the P30 package LSD, so I wanted to keep that - otherwise the whole thing would have been a simple affair of bolting on the Chrysler diff directly.. The bigger gear needed to be homed inside the Chrysler diff but with the AMG propshaft four-pointy-thingy flange.
I can't remember the other misc parts needed, but in a nutshell, i think diff fluid and the TCU strech bolts are pretty paramount.
I'm not sure. I understand when you say the bigger Gear needed to be honed inside the Chrysler Diff?? Had not the bigger gear come from the Chrysler Diff in the first place???
So Again, did you take the Ring & Pinion from the Chrysler SRT8 and swap into the AMG Diff? Please read my previous post and answer accordingly so we can all be certain of how to go about making the plunge to make this conversion.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
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