Built Diff...

[SYT_Shadow]

On one hand you have Mr Bone dogbone kicking ass and taking names with his E90 with the OSG diff. However, on the other, both Dan from diffsonline and Florian from driftflo both don't like OSG.

Florian/driftflo even tests at least 2 OSG configs and says they both aren't very good.

I suspect almost anything is better for serious track use than the OEM one

[SYT_Shadow]

Originally Posted by rhyary

The packaging is also important.
I am not familiar with all the options, but what is nice from diffsonline is that you get the whole housing from them all complete. You send yours back.

This is built by a shop that does it for a living. So there is a certain comfort that the assembly of the 3.62, LSD and the housing was done right. All the installer has to do, whether DIY or the local shop, is install the whole unit. The downtime for your car is minimal, but you need to do 1000 break-in and change the diff oil at the end of the 1000 miles

If all the LSD providers can do the same, then pick any of them.

I am just saying you are not only picking the LSD, you are picking a 3.62 solution.

For a pretty reasonable price I got Florian/driftflo to quote sending a full pumpkin that just had to be added to the car. So then you'd keep your diff as a spare.
I also do not want random people assembling the diff incorrectly

[nicksm3]

More great info! Thank you guys....
Again, I know crap...just want my car to feel like a raptor clawing out of corners ☺️

[Kelse92]

nicksm3 I feel your pain on all this stuff lol. The world of learning diffs is endless! I've been casually shopping for my car and leaning towards the Drexler setup from Driftflo. It seems to be the best bang for the buck and ability to customize for your setup.

[bigjae1976]

Originally Posted by dogbone

The OS Giken Superlock can be custom setup by OS Giken to however you want it. (It's a $150 service on top of the price of the diff)

Check out this form you fill out if you want a custom setup. They encourage you to upload dyno charts and pictures of your aero so they can really dial things in.

https://docs.google.com/forms/d/e/1F...Oi4ig/viewform

https://osgikenusa.com/products/lsd-...on-domestic-49

Again, the only downside with OSGiken is that they are cagey and vague about the exact preload setup because they consider it proprietary info. But you can see what ramp angles they use and you can see how many clutch plates are active. The preload is the only thing you don't know about. If you are super technical and you need to know, then this unit may not be for you. But in terms of being able to customize the unit, yes, they can make that unit dance for your specific car, tires, aero, power, dyno charts, etc. And as far as I know, 10 sets of clutch plates (20 total plates) for the E9x M3 is more than any other unit I've seen. More clutch plates, if setup properly, lead to smoother locking and unlocking of the unit. Also, OS Giken makes their own diff fluid which I use. It's a 80w-250 weight.......serious stuff.

There is nothing really custom with a ZF unit and complete units and parts are relatively easy to find. The ZF LSDs used to go for$200-$300 for a complete diff so it was a no brainer. Now they go for $800-$1500 (depends on the FD ratio) so it's not an easy decision. I got my 3.73 ZF LSD from an E24 635CSi for $250.

It is easier to get more lockup with an OS Giken but lock % is only a part of the equation. The ZF allows easy tuning of the ramp angles and preload.

If lock up was the most important feature then you'd go with the OE M-Lock which locks up to 100%.

[Richbot]

Originally Posted by SYT_Shadow

I'm basing what fits and what doesn't off dogbone 's thread

275/35 fits perfectly. 285/30 R1 is super wide and requires fender liners to be removed. We'll see how that part works out.

I don't want a 3.45, it kind of feels like what's the point then. But a top speed of 152... WGI and VIR both pass that today

WAit, what? Stock gearing is good for well over 200mph (207-209ish?) at 8400rpm in 7th? How does going up to a 3.62 and a shorter tire drop that by more than 50mph?

According to this calculator (which I've found to correlate pretty closely to real world in the past), a 3.62 should be good for 171mph with a 24.7" tall 285/30-18 in 7th which is enuogh for any sedan car making under 500whp just about anywhere, if it's running a wing anyway

www.bgsoflex.com/auto.html

[SYT_Shadow]

Originally Posted by Richbot

WAit, what? Stock gearing is good for well over 200mph (207-209ish?) at 8400rpm in 7th? How does going up to a 3.62 and a shorter tire drop that by more than 50mph?

According to this calculator (which I've found to correlate pretty closely to real world in the past), a 3.62 should be good for 171mph with a 24.7" tall 285/30-18 in 7th which is enuogh for any sedan car making under 500whp just about anywhere, if it's running a wing anyway

www.bgsoflex.com/auto.html

My math seemed to be off, 170 is correct

[rhyary]

Originally Posted by SYT_Shadow

My math seemed to be off, 170 is correct

This is what I got with 295/30/19 (26" diameter)
and 8300 rpm:
.

[fsmtnbiker]

Originally Posted by SYT_Shadow

On one hand you have Mr Bone dogbone kicking ass and taking names with his E90 with the OSG diff. However, on the other, both Dan from diffsonline and Florian from driftflo both don't like OSG.

Florian/driftflo even tests at least 2 OSG configs and says they both aren't very good.

I suspect almost anything is better for serious track use than the OEM one

I've got the Drexler from Florian in my E92, and have an OSG in my E36.

Both units work well, the OSG has TONS of setup options and most people get them really wrong, which is why OSG has started only doing tuning in-house and being very tight-lipped on setup info. There are different ramps, preloads, clutch active/deactivated configurations, and delay springs all as tuning options is the OSG... And its very easy to go the wrong way or go way too far and have a diff that doesn't work.

Both Florian and Dan probably cannot get the parts to tune an OSG anymore, so it would make sense for them both to focus on offerings they feel they can tune and dial in well for a customer. I considered all the options when I bought the E92 diff. I probably would have purchased an OSG based on my experience with them in the E36, but they were out of stock and had a long lead time... and I'm impatient. Plus Florian has really given a lot of his time and information to the community here and I'm happy to support that!

[SYT_Shadow]

Originally Posted by fsmtnbiker

I've got the Drexler from Florian in my E92, and have an OSG in my E36.

Both units work well, the OSG has TONS of setup options and most people get them really wrong, which is why OSG has started only doing tuning in-house and being very tight-lipped on setup info. There are different ramps, preloads, clutch active/deactivated configurations, and delay springs all as tuning options is the OSG... And its very easy to go the wrong way or go way too far and have a diff that doesn't work.

Both Florian and Dan probably cannot get the parts to tune an OSG anymore, so it would make sense for them both to focus on offerings they feel they can tune and dial in well for a customer. I considered all the options when I bought the E92 diff. I probably would have purchased an OSG based on my experience with them in the E36, but they were out of stock and had a long lead time... and I'm impatient. Plus Florian has really given a lot of his time and information to the community here and I'm happy to support that!

That could be the answer.

Although then that begs the question, the OSG is dirt friggin cheap at ~2k. The Drexeler is ~6k, the Race Carrier Diffonline one is even more.

[fsmtnbiker]

Originally Posted by SYT_Shadow

That could be the answer.

Although then that begs the question, the OSG is dirt friggin cheap at ~2k. The Drexeler is ~6k, the Race Carrier Diffonline one is even more.

Did the price/exchange rate change recently? I got the 8-clutch "GT Race Light" diff with bearings, seals and drive flanges for 3000€ (~$3500 USD at the time) to my door. I assembled it into my stock housing, but that would be the case for an OSG as well.

[SYT_Shadow]

Originally Posted by fsmtnbiker

Did the price/exchange rate change recently? I got the 8-clutch "GT Race Light" diff with bearings, seals and drive flanges for 3000€ (~$3500 USD at the time) to my door. I assembled it into my stock housing, but that would be the case for an OSG as well.

I was quoted over 5k euro, although granted that was with a 3.62. Still, a decent difference

The usd to eur is getting close to 1:1

[tsk94]

Originally Posted by fsmtnbiker

Did the price/exchange rate change recently? I got the 8-clutch "GT Race Light" diff with bearings, seals and drive flanges for 3000€ (~$3500 USD at the time) to my door. I assembled it into my stock housing, but that would be the case for an OSG as well.

Did you get a different final drive when you ordered from Florian? Mine, with final drive and all parts (flanges, seals, etc.) was €4000 + shipping. On top of that is obviously the cost of installation into your existing or new housing. Figure ~5k€ if installation is included - very similar to what SYT_Shadow was quoted.

[fsmtnbiker]

Originally Posted by SYT_Shadow

I was quoted over 5k euro, although granted that was with a 3.62. Still, a decent difference

The usd to eur is getting close to 1:1

Ah yeah, I did not alter the final drive as i wanted to keep the car legal for the autocross class I run it in occasionally.

The LSD unit itself was listed at $2100 euro on my bill, so I'm just not seeing where the OSG is a whole lot cheaper at ~$1800 USD. The OSG still needs bearings, seals, etc plus a ring & pinion and assembly.

[Redd]

Fwiw, the OSG makes zero noise so its daily driveable. OSG also claims long service life and it does not need to be rebuilt, but I haven't had mine long enough to test that claim.

[SYT_Shadow]

Originally Posted by SYT_Shadow

I was quoted over 5k euro, although granted that was with a 3.62. Still, a decent difference

The usd to eur is getting close to 1:1

Update:

The lsd itself is 2100Euro
Then the different final drive is 500E, the used pumpkin is 1000E, install/etc and shipping takes you to 5k

So maybe the drexeler diff is the same price as the osg

[CorruptCommie]

Originally Posted by SYT_Shadow

Update:

The lsd itself is 2100Euro
Then the different final drive is 500E, the used pumpkin is 1000E, install/etc and shipping takes you to 5k

So maybe the drexeler diff is the same price as the osg

When I was shopping for a fully built diff with R&P change for the E46, Drexler was around $5k-$6k, OSG was a little under that, and I ended up sourcing a racingdiffs rebuilt ZF and all the parts and had a local guy build it for $3k. Dan's pricing just couldn't compete.

[//steve\\]

Lots of good info in here. What are you guys doing to make the speedo read correctly? Is that taken care of with the trans tune?

Anyone that's done a final drive change on a 6MT car have comments? I know lots of guys just don't care and a shorter final drive just means the speedo reads high so no real worries of getting pulled over by surprise.

My car will always see lots of time on the street so I'd like everything to work as if it's OE. My last S2000 had a geared diff and there was an easy inline solution (https://modifry.com/index.php?route=...=61install.htm)

Just turn a few knobs and it would just alter the signal going to the speedo. Has anyone done anything similar? Of given that it's a European car where you can code and change so much already, is it possible to do OE?

[tsk94]

Why would anything need to be changed for the speedo to read correctly? Am I missing something? I've never heard of a final drive swap causing issues with accurate speedometer reading - at least with BMW's. Maybe it's different with Hondas?

[//steve\\]

Originally Posted by tsk94

Why would anything need to be changed for the speedo to read correctly? Am I missing something? I've never heard of a final drive swap causing issues with accurate speedometer reading - at least with BMW's. Maybe it's different with Hondas?

Could just be an issue with Hondas....not sure which is why I asked.

I can tell you though for a fact that my car running with a 295/30/18 rear tire has the speedo reading high by a fair bit....when the speedo says 80 I'm only doing 73-74-ish....the smaller tire in some ways is like shortening the final drive.

[SAMM3Y]

Originally Posted by //steve\\

Could just be an issue with Hondas....not sure which is why I asked.

I can tell you though for a fact that my car running with a 295/30/18 rear tire has the speedo reading high by a fair bit....when the speedo says 80 I'm only doing 73-74-ish....the smaller tire in some ways is like shortening the final drive.

Speed sensors are on the wheels on our m3s, and they notoriously read off about 4mph anyway.

[//steve\\]

Originally Posted by SAMM3Y

Speed sensors are on the wheels on our m3s, and they notoriously read off about 4mph anyway.

yeah, I'm not surprised to find it off by a little bit but 6-7mph seemed like it was maybe a little high.

That said, I have to imagine the speed sensor has to be calibrated on some level to some kind of fixed number like tire diameter or final drive so any change should throw that off. I wouldn't think the car would just know.