[feuer]

Originally Posted by Aus335iguy

I don't know about balance but the chassis stiffness comment piqued my interest and I may be about to take this thread on a tangent so sorry in advance. Its a moot point once you had a cage.
Traditionally at least, Coupes were the sportier variant for a lot of makes and models because less doors means more welded chassis and higher rigidity as a result.

For those interested :-
This thread, http://www.e90post.com/forums/showth...=340216&page=2

specifically says that E92s are 25% stiffer. I followed the link in the thread but its expired but i still believe that the coupe would be stiffer.

Maybe that is why BMW build e90 320si for FIA WTCC yes? I'm yet to read official BMW publication on the matter. Not only BMW but most cars when you lift one side only, jack it up in the middle, the door won't align anymore on the coupe. Sedans not so much because right in the middle is the B pillar. That is not a test of course. Just a mere observation of what happens that leads me to think sedan is stiffer.

[feuer]

Originally Posted by sirdaft1

Below is the stock 335 lower control arm (bottom horizontal blackish/grayish piece). Because we need new suspension anyways, replacement M3 lower control arms on order to properly fix the stock crappy 335 design that uses a rubber bushing where the strut mounts to the lower control arm. The plan is to run 335 front suspension with M3 rear suspension since we're replacing the suspension with MCS's anyways. The m3 version uses a solid mount which translates to far less slop and better response/feedback

If planning to do this same upgrade that requires m3 rear struts, it's worth mentioning that brand new lower m3 control arms can either be bought new for $200+ per side ($400 total from Bimmerworld, ECS, etc.), or good condition used versions can be found ALL OVER eBay for a fraction of that. I found a good used pair for $150.

And for anyone wanting to upgrade from the crappy rubber bushing without going full M3 mode, AKG makes a rear lower shock mount which adapts the stock 335 rear dampener to a solid spherical bearing setup. That said, NVM will likely be increased.
I come from the e30 world prior to this and the 335 guibo is about twice the size of the e30's! It's YUUUGE.

The m3 arms allow better shock articulation which makes the rear suspension to be more compliant. Uses different bolts which are longer too. There are adapters for non m arms to accommodate m rear shocks. Since you have experiences with e30 I assume you are aware of camber shims. The shop I'm associated with has them. Work great on race cars. Also for the rear, the diff, try to mount finned cover from e60/61 fro better cooling. My shop also has lockdown kits that work with the finned diff cover. This last weekend I installed aluminum guibo and aluminum engine mounts. Difference is very noticeable. Go for it.

[Aus335iguy]

Originally Posted by feuer

Maybe that is why BMW build e90 320si for FIA WTCC yes? I'm yet to read official BMW publication on the matter. Not only BMW but most cars when you lift one side only, jack it up in the middle, the door won't align anymore on the coupe. Sedans not so much because right in the middle is the B pillar. That is not a test of course. Just a mere observation of what happens that leads me to think sedan is stiffer.

Chassis stiffness wouldn't have been on their minds at all or very little when selecting the race car model as a cage would overcome any shortcomings anyway. It's usually marketing that decides which car ends up being the poster child and it's usually the cooking models that get the nod.
Secondly when looking at the door on a coupe the door is almost twice as long and so yes the coupes doors would show the flex more because it's over a longer distance. So that's evidence but not a conviction.
I think the fact that BMW hasn't released the number officially that I can find might mean that they are in fact the same ....

Unless someone has the numbers I guess we'll never know

[sirdaft1]

Originally Posted by Aus335iguy

Chassis stiffness wouldn't have been on their minds at all or very little when selecting the race car model as a cage would overcome any shortcomings anyway. It's usually marketing that decides which car ends up being the poster child and it's usually the cooking models that get the nod.
Secondly when looking at the door on a coupe the door is almost twice as long and so yes the coupes doors would show the flex more because it's over a longer distance. So that's evidence but not a conviction.
I think the fact that BMW hasn't released the number officially that I can find might mean that they are in fact the same ....

Unless someone has the numbers I guess we'll never know

Interestingly, as we're building this cage... My builder did mention that the narrower e90 front door will make it more challenging to get in/out of the car compared to the longer door opening of the e92. Being a full 6'3", I'll report back on how challenging it is.

And this may not apply to the e9x chassis', but what little data I could find on chassis rigidity showed a massive difference between rear fold down seat/no rear fold down seat on the e46. Even with that, the below link shows far greater rigidity from the e90 compares to the e46 (again, roll cage with proper gusseting makes this a moot point)

https://www.bimmerforums.com/forum/s...idity-Humor-me

[Zoki]

Love this thread, I'm also making my E92 into a track beast albeit keeping it road legal.

How do you manage to run 18x10.5, I thought the limit would be 9.5 width or is this a E92 limitation. http://www.e90post.com/forums/showthread.php?t=651864

[sirdaft1]

Originally Posted by Zoki

Love this thread, I'm also making my E92 into a track beast albeit keeping it road legal.

How do you manage to run 18x10.5, I thought the limit would be 9.5 width or is this a E92 limitation. http://www.e90post.com/forums/showthread.php?t=651864

Do you have a build thread?

And we're going to be running a widebody kit. Otherwise on the pre-LCI e90 there would be considerable rubbing on the fender.

[sirdaft1]

Originally Posted by feuer

The m3 arms allow better shock articulation which makes the rear suspension to be more compliant. Uses different bolts which are longer too. There are adapters for non m arms to accommodate m rear shocks. Since you have experiences with e30 I assume you are aware of camber shims. The shop I'm associated with has them. Work great on race cars. Also for the rear, the diff, try to mount finned cover from e60/61 fro better cooling. My shop also has lockdown kits that work with the finned diff cover. This last weekend I installed aluminum guibo and aluminum engine mounts. Difference is very noticeable. Go for it.

Solid engine mounts make sense, but I can't help but question a solid aluminum guibo. I could be mistaken, but I feel like I've heard that you want a guibo that can absorb vibration, otherwise the vibration from the driveline can cause issues with the crankshaft. Again, I can be wrong but I feel like I've read threads about this happening on other BMW chassis forums.

[feuer]

Originally Posted by sirdaft1

Solid engine mounts make sense, but I can't help but question a solid aluminum guibo. I could be mistaken, but I feel like I've heard that you want a guibo that can absorb vibration, otherwise the vibration from the driveline can cause issues with the crankshaft. Again, I can be wrong but I feel like I've read threads about this happening on other BMW chassis forums.

1M, 335is and newer "regular" 335i's, like all n55 received aluminum guibo from factory. I do a lot of hard shifts and I'm able to tell the difference. Whether good or bad about the crankshaft I don't know. The rubber piece has voids and flexes which is noticeable with sticky tires.

[Zoki]

Originally Posted by sirdaft1

Do you have a build thread?

And we're going to be running a widebody kit. Otherwise on the pre-LCI e90 there would be considerable rubbing on the fender.

I don't have build thread, doing everything DIY and budget so everything is slow progress.

Fair enough, should look good with the bodykit! Shame there isn't one for the E92. I did read somewhere Hard Motorsport were going to make one? Wonder what happened. May ask a bodyshop about the ££ to do a custom one.

Are you running spacers, I imagine there might be clearance issues with 10.5j on the inside with the strut?

[sirdaft1]

Originally Posted by Zoki

Are you running spacers, I imagine there might be clearance issues with 10.5j on the inside with the strut?

For now, yes. Love Apex wheels but unfortunately they don't make a set of wheels with the proper offsets to fit this widebody. That said, we'll probably go with some custom BBS's or similar at some point to get proper offset.

[sirdaft1]

Got a couple of photos sent over from eFab today. Progress!

Anything notice something a bit off about the cage in pic #2??

[sirdaft1]

I've never been asked to wear a helmet during a oil change in the past. Very odd... starting to suspect that eFab is up to something that goes beyond a simple oil change...

From my quick 3-hour visit to eFab tonight to check seat location and fitment above my head. These e90's are pretty damn surprising in seeing just how much room they have. I'm 6'3" and with a halo seat, I have quite a bit of head room!



These cages take ALOT of time to make sure you have proper fitment and symmetrical pieces (drivers/passengers sides). That said, major parts are bent and the rest should go together pretty quickly. Eric said most of the cage should be done by Friday of this week/early next week depending on how tough the door bars are. Quite a few more shots from the inside...






Instead of the X style structure, we went with an A frame. This allows us to make the open area above the drivers head (me) much smaller than if it were a traditional X structure, providing more safety in the event of a rollover. #themoreyouknow



Also, the difference with the A-pillar bars in this photo vs my previous post were that these completed ones are one continuous bar vs multiple welded together pieces. The welded/multi piece version is how a template is made to find the right shape which can then be copied when bending one single piece of steel. Most major racing sanctioning bodies only allow three bends in the single A-pillar bar. Ours is bent in such a way that we'll be able to weld the bars to the actual body of the car, further increasing rigidity.

[Rain]

Coming up nicely! Head room with helmet was always a problem to me as well haha (although I'm 6'5"), but its a lot better in stock E92 sport seat than it was in my previous E46...

[BM91]

Originally Posted by J-Spec Dan

Aw snap! First new build thread that brought me back from a 2 year lurker status. This build will be sick #FTMFW

Originally Posted by mashimarho

You're still alive too?

LOOL

Soo many OG's on this thread.

[sirdaft1]

Originally Posted by Rain

Coming up nicely! Head room with helmet was always a problem to me as well haha (although I'm 6'5"), but its a lot better in stock E92 sport seat than it was in my previous E46...

I used to have to lean my stock seat WAAAY back to fit my melon in the stock interior. It's pretty incredible to see how much more headroom room you get without carpeting or the sunroof. For someone needing even more room, one thing that we are NOT doing, would be to remove the stock seat mounting points and make a custom floor mount. The stock mounting points easily sit 1.5 - 2" above the floor pan which could be removed if headroom is needed.

[Zoki]

Nice progress, cage is looking good. Did you weigh the car before the cage?

Just ordered the same seat, they really were the most comfortable especially for someone taller. How have you mounted the your seat? I'm using macht schnell floor and seat belt receptacle.

I always felt that BMWs seat position was a little weird, felt the angle never lined up with the wheel and pedals, hope a bucket seat sorts that out!

[sirdaft1]

Originally Posted by Zoki

Nice progress, cage is looking good. Did you weigh the car before the cage?

Just ordered the same seat, they really were the most comfortable especially for someone taller. How have you mounted the your seat? I'm using macht schnell floor and seat belt receptacle.

I always felt that BMWs seat position was a little weird, felt the angle never lined up with the wheel and pedals, hope a bucket seat sorts that out!

Yes we did. Don't have the figure right this second, but we've been checking weight as we go along.

And we're using VAC Motorsports floor mounts. But we're finding that those VAC mounts don't shift the driver far enough to the center so we're working on a slightly modified version of the VAC floor mounts.

[Jeff@TopGearSolutions]

Cool build. Welcome back and best of luck!

[sirdaft1]

Originally Posted by Jeff@TopGearSolutions

Cool build. Welcome back and best of luck!

Thanks Jeff! Great to be back.

My fabricator just shot me these photos.... he drilled this hole in the floor...




And now this pipe is sticking through the bottom. Uhhhh... Any takers on what this could be for??

[Mantii]

Originally Posted by sirdaft1

Thanks Jeff! Great to be back.

My fabricator just shot me these photos.... he drilled this hole in the floor...




And now this pipe is sticking through the bottom. Uhhhh... Any takers on what this could be for??

That's for the shit bucket for the "oh shit" moment. That way you lay a nice trap for the next guy behind you muhah

[sirdaft1]

Originally Posted by Mantii

That's for the shit bucket for the "oh shit" moment. That way you lay a nice trap for the next guy behind you muhah

[sirdaft1]

Originally Posted by Mantii

That's for the shit bucket for the "oh shit" moment. That way you lay a nice trap for the next guy behind you muhah

And while I'm now going have Eric install this feature on the car now that you've mentioned it. It's going to be a support for the new jack point on each side (he'll be cutting down the tube and installing a plate on each side - otherwise it'll make for a very interesting experience when I drive over curbing as it currently sits!)