BMR Upgrade and Review

[Fraxum]

Edit: So many typos!

A month or so ago I upgraded my SS suspension with BMR Parts:

• Pro Cradle Bushings
• Pro Differential Bushings
• End Link Mounting Braces
• Adjustable sway Bars
• Sway Bar End Links
• Toe Rods
• Trailing Arms
• Driveshaft Safety Loop

I wanted to wait and drive with the mods before I reviewed the changes and attend a Track Day to really understand the difference in the car. I also took a 1,000 mile trip in my SS to Niagara Falls. This car is my daily driver, but since I work from home I am putting on under 10.000 miles per year.

Race Proven Motorsports in Delaware installed the BMR parts. They took their time and I am happy with their work.

I chose not to lower my car. Besides scraping more often lowering springs also hurt you at the drag strip (edit: I have since learned a 1 inch drop has no or a very small effect). If later I get more serious I will spring for coil overs (sorry).

I kept my alignment specs stock. Street qualities are more important to me than track qualities


My goals:

• Less understeer
• Eliminate Wheel Hop
• Eliminate rear step-out due to rubber bushing play
• Feel more in control
• Improved performance at the track

I was also hoping for a lighter feeling agile car. But I did not think these changes would help on that front. I was right.


I knew I would make some sacrifices. I found:

• Slightly stiffer and more harsh ride. But long trips are still comfortable.
• Noticeable drivetrain whine, especially in sixth gear. High pitched but not loud, I am already used to this.

Other than that, the handling feel of the car is notably improved. Cornering is much more stable and my SS now handles on a par with my departed 335i. Although the 335 had better steering feel and felt more agile, the cars are not that far apart.


Improvements:

• Understeer: Big improvement but there is still some left. My Sways are still on the middle setting, my alignment specs are stock, and I am still running staggered stock tires. As I am no track superstar I think some understeer is a good thing for me right now.
• Eliminate Wheel Hop: I have not been to the strip yet. But I tried a few hard launches and did not feel the dreaded hop. I did launch hard in the rain and the hop was still there.
• Rear Step Out: Cured!
• Feel more in control: Yes.
• Improved Track Performance: While I have no before and after my SS feels at home on the track.

I attended a Track Day at the New Jersey Motorsports Park in Millville, NJ on the ThunderBolt track. ThunderBolt they tell me, is a very technical track, but not all that fast. Sounded perfect for me to learn on.

Early in the morning there was a general driver meeting followed by a raffle. I won a set of Race Ramps!

Myra, my instructor has been racing for nine years, and currently races a Miata. She makes a living as an instructor. Getting ready for my first run I discover a flaw in the trakability of the 5th Gen Camaro. If you have a sunroof and you are six foot or more your helmet hits the roof. Track Camaro = no sunroof. After a while I got used to driving with my head tilted sideways.

Myra took the first few laps at the wheel explaining track day etiquette, flag meanings, and the racing lines of the track. She at first we put off by the size of the Camaro. But than as she became more comfortable she started smiling and going faster. Before too long we were running up the butt of a yellow C6 Corvette. She said, "Don't try this at home." I held on for dear life. afterwards she said "Big power, great brakes, no fade. This thing, although huge, can get around the track."

My turn. I was much slower. So slow in fact I had a train behind me for a few laps. After my first session I improved and created no more trains. With help from Myra I was able to master several of the turns. Turn 2 was fun. It is an uphill right hand sweeper. She convinced me to stay off the brakes and slowly dial in more power through the turn, "Trust the car." She said over end over. By the end I listened to her and it became my favorite turn. She also spent the day trying to get me to take her Miata racing line through the "Octopus". On my last run I (almost) nailed it twice.

By the end of the day only one C6 in my class could catch me and go for a pass. I lapped a couple of cars and ran down a few others. The car was very stable in the turns and I was able to steer through many of the turns with the throttle. In the Octopus I was I was able to rotate the car with the throttle after a strong push on the brake. I felt like a hero. (in the beginner A class, lol.) But in the end I felt like it was as much or more the car as me.

All in all I am very happy with my BMR suspension mods and there will be more track days and the drags in my future.

Most BMWs were no problem for the BMR SS.

Here the Vette has the correct line. I missed this apex in the Octopus.

Future Plans:

• Hawk HP Pads
• 18" Lightweight Wheels with 275s all around
• Front bushings
• Performace alignment
• More power

[Squintz Palladoris]

Great Writeup Fraxum!

[edgar3]

excellent, thank you! I do the same event august 27th. I'll know what to expect. Why the blue tape in some of the track pics? (protection I assume)

thanks again for turning me onto it!!

[Fraxum]

Originally Posted by edgar3

excellent, thank you! I do the same event august 27th. I'll know what to expect. Why the blue tape in some of the track pics? (protection I assume)

thanks again for turning me onto it!!

Yes the blue tape is for protection. Actually another guy had the tape and offered me some. Nice guy. But while he was helping me apply the tape in the back, he taped over my brake lights. Doh! I got heat for that. In the pics here the brake light tape is off.

I had a movie camera attached to the dash, but my instructor wanted everything out of the interior. Maybe next time.

You will have a blast.

[brantley847]

why would lowering hinder you at the strip if it eliminates most wheel hop? I lose a time hopping around on the line...

I just cannot see a 1" hindering? now I have heard anything past a 1.5 will.... I will research this as well before I do my install..

[unseen423]

very fun track...did a few trackdays at njmp with my r1 and daytona 675.

Nice writeup too

[Fraxum]

Originally Posted by brantley847

why would lowering hinder you at the strip if it eliminates most wheel hop? I lose a time hopping around on the line...

I just cannot see a 1" hindering? now I have heard anything past a 1.5 will.... I will research this as well before I do my install..

The wheel hop cure is usually considered:

* Bushings
* Toe rods
* Trailing Arms

Not sure if lowering springs help with wheel hop. But the reason they may hurt on the strip is reduced weight transfer on the launch. There are some threads on this. But as for me I am no expert. Others here may know better...

[BMR guy]

Great writeup Fraxum! It's nice to see such a detailed review and the first-hand perspective of your track day will make this a very popular thread. As much fun as you had, I would like to point out a few suggestions that will make your next track day even better.

Sway Bars - As you continue to push your car you will get more comfortable with it. When you are ready to remove the understeer completely and neutralize the car all you have to do is put your rear bar on the stiffest hole (leave the front bar where it is). Our bars are designed so that when replaced together and using the same holes front-to-back, the overall roll stiffness is increased almost equally (slightly biased towards the rear). To effectively remove the understeer completely just stagger the mounting positions so that the rear bar is one setting stiffer than the front.

Alignment - You mentioned that you kept your alignment stock because "Street qualities are more important for me than track qualities". I can understand your thought process however a performance alignment will make a huge difference in how the car feels on the street or the track. If you set your car to our "Performance Street" alignment settings listed HERE, I can guarantee you the car will feel noticeably better and have very minimal impact on your streetability (slightly increased treadwear).

Just one other thing I noticed when looking at your pictures is that the rear sway bar is on upside down. The very slight bend on the outer lever arms mimics the OE curve and should face upwards. This will probably never be a problem on a stock height car but if you ever lower it, the bar can contact the subframe if you don't flip it over.

Again, great write-up and thanks for the feedback!

[Fraxum]

Originally Posted by BMR guy

Great writeup Fraxum! It's nice to see such a detailed review and the first-hand perspective of your track day will make this a very popular thread. As much fun as you had, I would like to point out a few suggestions that will make your next track day even better.

Sway Bars - As you continue to push your car you will get more comfortable with it. When you are ready to remove the understeer completely and neutralize the car all you have to do is put your rear bar on the stiffest hole (leave the front bar where it is). Our bars are designed so that when replaced together and using the same holes front-to-back, the overall roll stiffness is increased almost equally (slightly biased towards the rear). To effectively remove the understeer completely just stagger the mounting positions so that the rear bar is one setting stiffer than the front.

Alignment - You mentioned that you kept your alignment stock because "Street qualities are more important for me than track qualities". I can understand your thought process however a performance alignment will make a huge difference in how the car feels on the street or the track. If you set your car to our "Performance Street" alignment settings listed HERE, I can guarantee you the car will feel noticeably better and have very minimal impact on your streetability (slightly increased treadwear).

Just one other thing I noticed when looking at your pictures is that the rear sway bar is on upside down. The very slight bend on the outer lever arms mimics the OE curve and should face upwards. This will probably never be a problem on a stock height car but if you ever lower it, the bar can contact the subframe if you don't flip it over.

Again, great write-up and thanks for the feedback!

Thanks for the info. I will try that alignment and bump up the rear bar for my next try at the track. And I can probably get my installer to flip the bar over. Also wasn't there a way to tell if the end links are installed correctly?

[Rockit_z28]

Excellent review and could not agree more.

[BMR guy]

Originally Posted by Fraxum

Thanks for the info. I will try that alignment and bump up the rear bar for my next try at the track. And I can probably get my installer to flip the bar over. Also wasn't there a way to tell if the end links are installed correctly?

The end links should have equal movement for the top and bottom rod end when the car is at resting height. In other words, if you twist the end link from side to side, the rod end housing should be in the middle of its rotational range with the suspension loaded (not hanging). Rod ends have a specific articulation range of about 14 degrees. This is enough but doesn't leave much margin for error so it is important to make sure they are indexed correctly.

Something else I thought I would mention about lowering. I realize you are looking into coil-overs but I just wanted to alleviate any doubt that lowering the car conservatively will hurt your drag strip performance. I can understand your hesitation to lowering when it comes to drag racing as this has been a very popular and misunderstood topic on the boards. Our test car runs consistent 1.54 60 ft/times with our 1" lowering springs. We leave the line pretty hard and have never hit the bump stops at launch. The increased rate actually helps us off the line at the drag strip and the lower center of gravity makes a huge difference on the road course. Brantley847 is right, lowering springs don't typically hurt your drag strip performance until you lower the car beyond 1.4". This not only makes it difficult to achieve proper alignment specs but also shortens your available shock travel to a point that you can hit the bump stops at launch...

[Fraxum]

Originally Posted by BMR guy

Something else I thought I would mention about lowering. I realize you are looking into coil-overs but I just wanted to alleviate any doubt that lowering the car conservatively will hurt your drag strip performance. I can understand your hesitation to lowering when it comes to drag racing as this has been a very popular and misunderstood topic on the boards. Our test car runs consistent 1.54 60 ft/times with our 1" lowering springs. We leave the line pretty hard and have never hit the bump stops at launch. The increased rate actually helps us off the line at the drag strip and the lower center of gravity makes a huge difference on the road course. Brantley847 is right, lowering springs don't typically hurt your drag strip performance until you lower the car beyond 1.4". This not only makes it difficult to achieve proper alignment specs but also shortens your available shock travel to a point that you can hit the bump stops at launch...[/FONT][/COLOR]

OK, I stand corrected on that one. 1.54 is awesome. I bet that is with the good driver mod.

[mlee]

Originally Posted by Fraxum

OK, I stand corrected on that one. 1.54 is awesome. I bet that is with the good driver mod.

One guy in our club consistently lays down 1.55 60' with zero suspension mods and 18" DRs... the rest of us all run BMR and have great results too but there is something to say for the stock springs and getting some squat off the line... His Whipple doesn't hurt either...

[Fraxum]

Originally Posted by mlee

One guy in our club consistently lays down 1.55 60' with zero suspension mods and 18" DRs... the rest of us all run BMR and have great results too but there is something to say for the stock springs and getting some squat off the line... His Whipple doesn't hurt either...

Well I guess the point is that it does not seem that a 1 inch drop affects the launch much if at all. I thought it would have a negative effect, but that was a small part of the reason I avoided the drop. My primary reason was to avoid scraping.