raising trailing arm brackets

[BeirBrennerE30]

I had an original and unused DTM subframe for a week to take measures. The subframe is indeed raised by 12mm. The bell holding the diff is also different from a stock one.

Interesting, I was aware the portion of the subframe that held the diff was different since the diff was raised so far in the chassis. Did you ever post the measurement you took of the DTM subframe anywhere? I would be interested in seeing the changes from stock. Did you have access to the trailing arms as well?

[Massive Lee]

For something so basic to the e30 there's not allot of facts out there about it.

All your facts and measurements were established 10 years ago when I came out with the parts. Look around. They are there. ;-)

Raising the subframe by 12mm was so efficient that it didn' even require those adjusters/sliders. ;-)






@BeirBrenner - I had access to a full set. Subframe and 3rd generation DTM trailing arms. I shall find some pictures somewhere. Measurements were taken. Production agreements were set. Then found that the investment in time and money wasn't worth it. But I also found that my design for raising the subframe was pretty close to what Motorsport had done on their subframe.

[Massive Lee]

[LowR3V'in]

thanks lee
its just that i'm seeing people saying raising the car 12mm is the same as raising the subframe 12mm so idk what to believe.

i have 9mm raisers
thinking of switching those out for 12mm if it will make a difference but i can't find any calculations on what that would be in *.
with the 9mm raisers and basically half way up the ie adjuster slots it got my camber to 0, but the bushings where binding so bad it's just a shit show. if you haven't seen my thread in the suspension section. i'm going to buy that joint setup if my camber is still fucked up.

and hoveringguy if u used the stock location for the end of the toe-in adjustment you're going to have a bad time :( looks like it's going to be toed-out af, mine was.

[Massive Lee]

thanks lee
its just that i'm seeing people saying raising the car 12mm is the same as raising the subframe 12mm so idk what to believe.

Let's not forget either that lowering the shell onto the subframe also lowers the car's roll center.

https://en.wikipedia.org/wiki/Roll_center

Lee

[E30SPDFRK]

thanks lee
its just that i'm seeing people saying raising the car 12mm is the same as raising the subframe 12mm so idk what to believe.

i have 9mm raisers
thinking of switching those out for 12mm if it will make a difference but i can't find any calculations on what that would be in *.
with the 9mm raisers and basically half way up the ie adjuster slots it got my camber to 0, but the bushings where binding so bad it's just a shit show. if you haven't seen my thread in the suspension section. i'm going to buy that join setup if my camber is still fucked up.

and hoveringguy if u used the stock location for the end of the toe-in adjustment you're going to have a bad time :( looks like it's going to be toed-out af, mine mine was.

As far as camber is concerned, raising the subframe 12mm is the same as raising the car 12mm. The wheels stay in the same place and the subframe moves up 12mm with both solutions. People claiming 4°+ of camber reduction are flat out lying.

Some people go from stock worn out subframe and trailing arm bushings to poly or similar riser bushings and get a larger result since the old bushings were putting the car ever farther out of alignment. But going from new centered bushings to new 12mm riser bushings will get you >1° of correction.

[Massive Lee]

... But going from new centered bushings to new 12mm riser bushings will get you >1° of correction.

From experience, it is way more than. Not to mention huge reduction in toe in.

[LowR3V'in]

wooops. thought i was posting but i edited.

hi from the future!

[E30SPDFRK]

Notice that the people that haven’t actually measured say things like “looked like it went down to -2 or so” and the people that have measured say “will correct .423° of negative camber”.

From my real world experience, they’re useless. If you want to reduce camber or toe you need to make adjustable mounts, and if you have the offset subframe bushings installed, those adjustable mounts will hit the body of the car.

I don’t doubt that some people have seen a noticeable difference, and that’s because they’re going from worn out stock stuff to new solid parts.

[BeirBrennerE30]

Let's not forget either that lowering the shell onto the subframe also lowers the car's roll center.

https://en.wikipedia.org/wiki/Roll_center

Lee

Just raising the subframe with everything else staying the same wouldn't lower the car, it would just raise the subframe into the chassis and raise the roll center. It might actually raise the car slightly since the spring perch on the trailing arm moves up since one end point of the trailing arm is moving up (the subframe) and the other doesn't change,(the wheel). Does that seem right?

I had seen the pics you posted of the DTM stuff on s14.net I think. Would you be willing to share the measurements you took via PM? I don't doubt reproducing that set up was expensive, not just that fab to the subframe and the custom trailing arms but also new swaybar setup, new axles and stub axles, probably not being able to use stock fuel tank with raising the diff, and reinforcing the rear towers for rear coilovers.

[hoveringuy]

I finally did get this done. Used the IE slotted adjusters and welded them in 12mm higher than stock. I did need to bias the toe adjusters forward and relieve them slightly to clear the gas tank.


Everything is installed and using my magic alignment string I have -1/16 toe and 2.5degrees camber per wheel, which is about exactly what I wanted and I have plenty of room for adjustment.


You will notice from the photo that:


1) the nut side of each bolt is welded in so that these are single-wrench adjustable. Works dandy!


2) There is extra welding material and general strengthening at the base of the bracket. I realized that mounting these 12mm higher increases the lever-arm of the bracket assys so that there is more torque on the subframe during braking/acceleration, and there will be more of a reaction force at the differential mount. I will be keeping a close eye on it this season of HPDE to look for issues.

[hoveringuy]

Just for fun.. what's the relative position of the TA pivot to the center of the wheel bearing? Perfectly level!

[LowR3V'in]

Just and FYI, guys, we installed a full CSS kit on a car this week and measured camber.
JOM rear coil overs almost at full low was 6 degrees,
after the install, same springs, the camber was reduced to a tire-friendly 1.5.

hey, sorry to clutter up ur thread but i was thinking about this recently

assuming the before of 6* that he was talking about was on busted ass bushings
i too have -1.4 with 9mm raisers and stock subframe.
not within spec but extremely close.


also, you can weld those long ass ie camber plates so the bottom sits right on the subframe,
adjust them into positive, and not even use half the length if u keep the toe in the same position it's pretty ridiculous.
super glad it worked out for you but i had to ditch the setup. see if you can get camber close to 0 with the same toe just curious.
i had to shave off some trailing arm bushing because it was binding so hard on mine.

[pazi88]

If someone needs I have cad pictures here for totally new raised trailing arm brackets: https://drive.google.com/open?id=1GR...CldDeaW_A2mOe_




Those also allow more adjustment room than stock ones.

I also have video about this: https://www.youtube.com/watch?v=XQCX2NQRxgA

[hasa]

Looks good. This is about the max you can rise the mouting points without touching the floor.