Fully Adjustable Front Control Arms DTM Style

[AndrewLang]

I probably need to replace my stock aluminum front control arms (its been more than 2 years). They are expensive. I have stared at Jakes DTM tour of the DTM front suspension over and over again and it makes me want to make my own fully adjustable lower suspension. But I know it would take me quite a while before I was happy with it and it might be cheaper to buy something already available. The only thing I have found is the AKG kit: http://www.akgmotorsport.com/catalog...Control%20Arms


They have a 1200 and 1800 dollar version. Has anyone tried this? I wish they would have used a material other than aluminum. I also found some peoples at home solutions:


http://www.e30tech.com/forum/showthread.php?t=105209


None of these designs is really as ideal as the DTM design which involves modifying the front subframe for the spherical bearing mount and moving the attachment points higher into the chassis to compensate for the lowered car. I'm curious to hear if anyone went to the trouble of doing a full DTM style lower front suspension or if anyone has tried the AKG kit (or another one that I don't know about).

Gustav did a nice write up I've been looking through as well: http://www.e30m3project.com/e30m3per...arms/index.htm . Here he talks about some of the compromises made on the design so that he could have the turning radius desired in a street car. That compromise is evident in the AKG design. They actually don't look that complicated. it's a couple 4130 tubes that are threaded with spherical bearings in each end. But of course actually creating it all and within the tolerances required to make it an improvement over the stock control arm isn't that easy of a task.

[TBest90M3]

hi Andrew,

I have arms that I believe are from the same run that Gustave's arms came from... They are on the car although I have yet to put it on track... If you want to take any measurements or perhaps a gander for your own project, let me know. My car is in Foothill Ranch but I do plan on having it towed up to Bullet soon for some dyno tuning, etc.

-Terry

[AndrewLang]

Such a small world. I would love to come by and take a look at your arms as well as the whole car. I live in Irvine, my parents live up in Foothill Ranch. I'll send you a PM with my contact info so we can get in touch.

[TBest90M3]

Looking forward to meeting up. I need to cruise by your shop one of these days.

-Terry

[///schwartzman]

I know John Mason had a hand in a few of Gustave's modifications, saw them in production... May want to give him a call.

[AndrewLang]

Looking forward to meeting up. I need to cruise by your shop one of these days.

-Terry

Terry,

I just sent you an e-mail with my information through S14. Shoot me your contact information.

[sprytel]

I am using the AKG parts, although I modified the subframe attachment point to include a double sheer joint, instead of the AKG single sheer. I did it for my own sake, not because I feel the AKG part is deficient in any way. AKG stuff are very well engineered parts.
I've been very happy with them overall, however, there was not a noticeable improvement in the way the car performed. They do change the way the forces are transmitted from the tires to the chassis, which should help alleviate some of the common subframe mounting point failures I have seen. They also allow for huge amounts of adjustability that you don't get with the factory arrangement.

[Houlbt]

This is the solution I ended up with on my car...


BMD Motorsport

[toreto]

I am using the AKG parts, although I modified the subframe attachment point to include a double sheer joint, instead of the AKG single sheer. I did it for my own sake, not because I feel the AKG part is deficient in any way. AKG stuff are very well engineered parts.
I've been very happy with them overall, however, there was not a noticeable improvement in the way the car performed. They do change the way the forces are transmitted from the tires to the chassis, which should help alleviate some of the common subframe mounting point failures I have seen. They also allow for huge amounts of adjustability that you don't get with the factory arrangement.

Do you think AKG are strong enouht for hill climbing races, the roads are in a very good shape but it is not a track?.

Do you think they will be and improvement over the old group A control arms that basicly are the same as stock with berings on the end to be adjustable, i am trying to decide what to get.


Thanks.

[toreto]

This is the solution I ended up with on my car...


BMD Motorsport

Where do you get this from?

[sprytel]

Do you think AKG are strong enouht for hill climbing races, the roads are in a very good shape but it is not a track?.

Do you think they will be and improvement over the old group A control arms that basicly are the same as stock with berings on the end to be adjustable, i am trying to decide what to get.


Thanks.

I'd suggest reaching out to AKG and asking. They are usually very receptive and accommodating.
My opinion is that the "group A" is essentially a stock design, that eliminates the ball joint out at the wheel. Perhaps they did that because the ball joints were prone to failure? No idea, but they really only offer a little adjustability to the track width and subsequently camber. Caster is still determined by the rear bushing location. It is also this configuration that puts huge amounts of stress into the subframe pick up point under braking which will fatigue the subframe. If it hasn't happened to your car yet, it will, or you're just not aware that it has already cracked.
The AKG style arrangement eliminates that by passing the braking forces directly to the rear pick up points. That may create other problems, maybe the rear pick up points will now be susceptible to failure instead of the subframe, but so far that hasn't shown to be the case. They also offer all of the track/camber adjustability of the "group A" style, plus caster adjustment.

[Houlbt]

Where do you get this from?

Had them made - along with a host of other bits for my race car build - http://www.s14.net/forums/showthread...ar-build/page4

[AndrewLang]

Just to post an update, I went back and forth with AKG a bit as I had heard good and bad things about their product. I checked around and from what I could find they were the cheapest off the shelf product I could find. Here's what Lisa told me:

The difference between the two kits is the material (6061 aluminum for the FK3036 and 7075 T6 alum for the FK303670), and the design, which makes the limited edition lighter. The difference between the two sets is about 2 pounds (just over 12 pounds vs. 14 pounds). The adjustability is the same.

When we first released these back in 2008, we incorporated stainless pins, which we learned in one case bent. Due to that customer report, we switched to a 12.9 grade bolt which was much sturdier (and sent this upgrade to all who had purchased the arms), and have had no problem reports since. We have sold these arms worldwide, and have had teams and shops make subsequent purchases for other cars, which is proof to us of their durability and our customers’ satisfaction.

I figured it would take me atleast 20 hours to design and make my own arms and be happy with them and I'd probably end up spending way more than I'd expect on materials so I decided to just bite the bullet and get the AKG limited edition arms.

[inastrangeland]

Let us know how they work and any pics of the install.

[TBest90M3]

Andrew, I get a good vibe from AKG. I've purhcased bushings from them and they actually tried to talk me out of getting a set of trans bushings.... Pretty rare that you'll find a business wanting their customers to save money that way... Anyway, I'm sure those arms are going to be awesome. Can't wait to see your car in person

Take it easy,

-Terry