[bgregg]

I guess I should start with my original goals:
ride height - success
streetable spring rates - success
camber plates / tire clearance - success

On to the first impressions: the body control / body roll control is what you notice right away. Just climbing in the car stationary and getting in the drivers seat you notice something is different. Tighter driving feel. I really wouldn't want any stiffer springs for street, and this feels like the springs are still comfortable, but a lot firmer.

Noises: Yes, you can create situations where there are metal-on-metal noises. You can also have situations where it is seemingly quite noise free. It really depends upon the road conditions. This suspension can take my driveway and speed bumps OK. It cannot take potholes or abrupt road height changes without complaining back with the metal-on-metal noise I mentioned. Don't know if that is anything unique to this kit, or a general coilover or camber plate observation. For someone with mostly good roads, this is tolerable. For someone with mostly bad roads, not what you want. Don't know if more isolation could be done for the person who wanted to add plastic or rubber isolators? Probably most needed to address the noise from the front. I think noise makes a huge impression on buyers, or might be a deterrent/turn-off for some.

I have the car in the shop again for the limited slip differential installation, so my first impressions are brief due to that. I'll try to cover some other points later.

[Liquidpaper]

Originally Posted by bgregg

I guess I should start with my original goals:
ride height - success
streetable spring rates - success
camber plates / tire clearance - success

On to the first impressions: the body control / body roll control is what you notice right away. Just climbing in the car stationary and getting in the drivers seat you notice something is different. Tighter driving feel. I really wouldn't want any stiffer springs for street, and this feels like the springs are still comfortable, but a lot firmer.

Noises: Yes, you can create situations where there are metal-on-metal noises. You can also have situations where it is seemingly quite noise free. It really depends upon the road conditions. This suspension can take my driveway and speed bumps OK. It cannot take potholes or abrupt road height changes without complaining back with the metal-on-metal noise I mentioned. Don't know if that is anything unique to this kit, or a general coilover or camber plate observation. For someone with mostly good roads, this is tolerable. For someone with mostly bad roads, not what you want. Don't know if more isolation could be done for the person who wanted to add plastic or rubber isolators? Probably most needed to address the noise from the front. I think noise makes a huge impression on buyers, or might be a deterrent/turn-off for some.

I have the car in the shop again for the limited slip differential installation, so my first impressions are brief due to that. I'll try to cover some other points later.

Sounds great. Congratulations!

What LSD are you going with? The MP-LSD, or something else?

[bgregg]

Yes, M Performance Limited Slip Diff. I know there are other options, but was not feeling as adventurous on that one. I have had my adventure on suspension!

[Liquidpaper]

Originally Posted by bgregg

Yes, M Performance Limited Slip Diff. I know there are other options, but was not feeling as adventurous on that one. I have had my adventure on suspension!

When I got my differential made, I asked the guy who made it what the difference was between his design and the M-Performance diff. He explained a few of the differences, but then said "regardless, any locking differential is better than an open differential."

Enjoy!

[Pparana]

You could get longer springs from another manufacturer with the same spring rate to increase the travel.

[bgregg]

Originally Posted by Pparana

You could get longer springs from another manufacturer with the same spring rate to increase the travel.

If anyone knows of a 2.5" ID coilover spring in 5.5" length with a spring rate of maybe up to 450 lb/in that would be perfection for me. Send me a link or post it here.

I am thinking catalog springs come in integer lengths only and probably in the nearest 50 lb/in increments. So what I described would probably be a "custom" spring made to order and not in a catalog.

http://eibach.com/sites/devperforman.../ERS_19_US.pdf


I think my "best" option right now is to take the 6" length spring at 440 lb/in that Ground Control has as an in stock item. I will be at stock ride height in front and can go no lower than that. Specifically I'll be at 25.75" to the wheel arch on stock tires/rims. Compromise of the options of staying put or changing.

Here is the link:
http://www.ground-control-store.com/.../II=784/CA=214

[Pparana]

Originally Posted by bgregg

If anyone knows of a 2.5" ID coilover spring in 5.5" length with a spring rate of maybe up to 450 lb/in that would be perfection for me. Send me a link or post it here.

I am thinking catalog springs come in integer lengths only and probably in the nearest 50 lb/in increments. So what I described would probably be a "custom" spring made to order and not in a catalog.

http://eibach.com/sites/devperforman.../ERS_19_US.pdf


I think my "best" option right now is to take the 6" length spring at 440 lb/in that Ground Control has as an in stock item. I will be at stock ride height in front and can go no lower than that. Specifically I'll be at 25.75" to the wheel arch on stock tires/rims. Compromise of the options of staying put or changing.

Here is the link:
http://www.ground-control-store.com/.../II=784/CA=214

At that point why not just put in the stock spring and just run the plates. I am sure you can get the spring rate height you want is you email a few race shops or manufacturers, race teams I run into have hundreds of springs and rates and lengths, should not be that hard to get what you need.

Or order the 400 6" spring and cut to 5.5 should then have a spring rate of 430 or so, since it is a linear spring you can cut it it will just get stronger in proportion to cut, 8 percent or around there.

[bgregg]

The lower half of my camber plates where the spring adapter is is different than everyone else here. My adapter plate is sized for 2.5" ID spring only.

GC sent me overnight the 6" 440# spring set for the front and it will be on the car tomorrow. I'll update pictures of the spring under normal load/wheels on ground and the ride height. So I am doing a lot of experimenting on this because I am the first one going down this road. I feel that GC and my local shop and I are cooperating with each other to get it to the most optimal solution for this car. The extra 1" of spring travel is a "good thing" in this case, since I think less opportunity for metal-on-metal "klunk" to happen vs. the 5" spring.

I kind of wanted to stay with the normal spring offerings because that is what other people will likely want to know.

[bgregg]

The stuff that comes off the front of the car. Mainly have to hammer off the lower spring perch from the tapered section of the front strut. And then in its place insert the threaded height adjuster. It should sit flush to the top of the strut body and over the tapered section. I think GC has all the dimensions from my car now and should be able to provide these correctly from now on. The picture shows what was removed (front):



Here is the front ready to re-install:



The rear install is just removing the OEM isolator (housing and rubber inserts).

[bgregg]

Here is the closeup with wheels on the ground with 6" front spring:


Notice that my mechanic tried to put in a homegrown noise isolator on the front height adjuster (not part of the kit) to try to make me more happy! Knowing I am trying to get this as quiet as possible.

The great outcome of this is no "klunks" where the 5" spring would have made the metal-on-metal sound on abrupt surface changes like potholes and uneven road height quick transitions. On the 5" spring, if I tried to take a speed bump at the same speed as the car in front of me, I would also "klunk". So I can now take speed bumps much better also. I have a half dozen speed bumps at my workplace.

The bad outcome (for some) would be the car staying at stock ride height with 6" springs. That does not bother me, since I am used to it and didn't like too low. Maybe 5.5" length spring would be the hot setup if it was still comfortable?

The 5.5" spring solution I didn't try, because I was worried about going too stiff for the street. And I was running out of time, since I have an alignment appointment tomorrow. So I am done with suspension changes, until the struts wear out.

Here is the current ride height at 25.75" front and 25.5" rear to the wheel arches.

[Liquidpaper]

Originally Posted by bgregg

Here is the closeup with wheels on the ground with 6" front spring:


Notice that my mechanic tried to put in a homegrown noise isolator on the front height adjuster (not part of the kit) to try to make me more happy! Knowing I am trying to get this as quiet as possible.

The great outcome of this is no "klunks" where the 5" spring would have made the metal-on-metal sound on abrupt surface changes like potholes and uneven road height quick transitions. On the 5" spring, if I tried to take a speed bump at the same speed as the car in front of me, I would also "klunk". So I can now take speed bumps much better also. I have a half dozen speed bumps at my workplace.

The bad outcome (for some) would be the car staying at stock ride height with 6" springs. That does not bother me, since I am used to it and didn't like too low. Maybe 5.5" length spring would be the hot setup if it was still comfortable?

The 5.5" spring solution I didn't try, because I was worried about going too stiff for the street. And I was running out of time, since I have an alignment appointment tomorrow. So I am done with suspension changes, until the struts wear out.

Here is the current ride height at 25.75" front and 25.5" rear to the wheel arches.

Looks great. Are you sure that you are at stock height? Looks just a teeny weeny bit lower.

[bgregg]

I guess this EDC damper thing is a "technology area" and they way I think about it in my mind is a feedback control system. The components of "sensors" being sampled at 100 samples/sec and "actuators", being the magnetic valves. And the software.

So the fact that even Dinan promotes keeping the EDC dampers, but just reprogramming them with new software kind of sends the message that the EDC dampers are worth keeping around. Even for higher performance levels.

When the EDC dampers do wear out, I guess there is a decision point. Do you pony up to get more of the same? Or do you go to aftermarket dampers and EDC delete? Is the Dinan EDC replacement software now part of the decision whether to stay EDC?

I remember that when Cadillac CTS-V first came out with its suspension equivalent of EDC, the car magazines were drooling all over it. So it is a technology that is probably here to stay now that they figured out how to get the costs down and insert into mass production.

I think the topic kind of relates to people who would purchase a ride height kit that retains EDC functionality.

(The fact that Dinan figured out Shockware for the 228i, led me to believe it was only a matter of time before figuring out M235i...maybe. But the principle of setting the car up to have at least two modes: "out on a date mode" vs. "racetrack mode" is what buyers will respond to.)

[bgregg]

The alignment went as planned today:

[bgregg]

Here is the suspension at full droop while changing the wheels to reconfigure to track set. I put my hand in there to see if the spring could be turned, and it is still quite tight at full droop. So that is also a positive thing, and I don't have to worry about special care for jacking the car up in the air.

[bgregg]

Have to do some calculations on my own, but my current theory is running square 235/40-18 on all 4 corners might be best fit and best for rotation. And it might be a bit closer to tire heights that stability control software is expecting too. And it is a stock size tire for R compounds, such as Toyo R888 and Nitto NT01.

In this photo the fronts are 235/40-18 and the rears are 245/40-18. The wheel offsets are +42.

[rwalker]

you've got front camber, why not go big: 255/35r18 all around?

[Pparana]

I am running r comps now on a square setup. Feels great but almost too much grip. Sometimes less grip is more fun. Going to square reintroduced the dreaded understeer I worked so hard to get rid of. I'll be on tracknext week w a few mods to springs and allingment we'll see. The tires I am running are 235 but there more like a 245 40 r comp size nittos.


Your setup square I am interested in track feel. Stiffer front springs and more tire up there should equal more under steer. I don't think you will need the roll bar., maybe in rear to increase oversteer. You could also dial out some rear camber to help w the understeer if it manifests ( you can take a 1/2 degree out, as long as you are within 1 degree front rear).

[rwalker]

Originally Posted by Pparana

Going to square reintroduced the dreaded understeer I worked so hard to get rid of.

Do you have a theory on why moving to larger tires up front caused you to lose grip on that axle? Did you change something else at the same time?

Originally Posted by Pparana

You could also dial out some rear camber to help w the understeer if it manifests ( you can take a 1/2 degree out, as long as you are within 1 degree front rear).

What are you basing the "within 1 degree front rear" guideline on? What are the consequences of running outside that envelope?

[bgregg]

I've been unhappy even with 245/40-18 track tires on the front. I doesn't look right to my eye, and it is something that requires -3.0 camber to pull it off correctly without being unsafe on the tight clearances. I attribute that to the fact the Toyo R compounds must run wider than the street tires, so my 235 track fronts are more like 245 street. Likewise, my 245 track rears are like 255 street.

So I am really happy with 235/40-18 on the front and -2.5 camber. Going square with 235/40-18 may be good for tire rotation and some safety margin of clearance in the rear. The rear clearance right now is just so close to the edge there is no margin for something unexpected. Running less camber in the rear than in the front is advisable.

My example of something unexpected is berm hopping. I normally don't berm hop on the track on purpose, since it also bends rims.

I've just been out driving left circles, right circles, and figure 8's trying to break in the limited slip diff. While I was doing that I left the track wheels/tires on to see if there were any signs of more rubbing. It is looking very good right now! I didn't get all the way to racetrack levels of testing, however, but did get a sense of the grip limits, which is pretty balanced and maybe a little understeer remaining. Smaller width rear tires would be neutral.

No big noises or clanking sounds in the suspension anymore. The level of noise I hear is pretty much exactly what rwalker and liquidpaper describe on their cars.

[Pparana]

Originally Posted by rwalker

Do you have a theory on why moving to larger tires up front caused you to lose grip on that axle? Did you change something else at the same time?


I did not loose grip, I gained grip, so the rears can not overpower the front, too much grip (relative to rear) can also cause understeer ( in different situations) Again I am just looking to keep the car balanced, favoring neither.

Car in last track setup had mild mid corner understeer between 60-80mph, so I stiffened rear springs and raised rear ride height. I will see how that works out.


What are you basing the "within 1 degree front rear" guideline on? What are the consequences of running outside that envelope?

That is pretty much the accepted tolerance for most road course track and race cars, unless you are severely modifying suspension. If you go ouside the parameters you will cause over or understeer.

For example Porsche ships the 991 with 2.8 rear and 1 front, this is so they are not tail happy. That extra degree is out of the norm, but so is the engine in the rear. Most people who track them align it back within the specs above.

Most race teams I know( endurance ) using bmw platforms seem to like under 2 or just around in the rear and 3 or so up front. That is what I have mine set to (1.9 rear , 2.9 front). Tire wear and temps on track is very good, so I am not planning on adjusting unless the temps change from new setup.

[rwalker]

Originally Posted by Pparana

I did not loose grip, I gained grip, so the rears can not overpower the front, too much grip (relative to rear) can also cause understeer.

How can too much front grip cause understeer? We agree that understeer means front sliding/pushing?

Originally Posted by Pparana

That is pretty much the accepted tolerance for most road course track and race cars, unless you are severely modifying suspension. If you go ouside the parameters you will cause over or understeer.

For example Porsche ships the 991 with 2.8 rear and 1 front, this is so they are not tail happy. That extra degree is out of the norm, but so is the engine in the rear. Most people who track them align it back within the specs above.

Most race teams I know( endurance ) using bmw platforms seem to like under 2 or just around in the rear and 3 or so up front. That is what I have mine set to (1.9 rear , 2.9 front).

Interesting examples. Note that I'm running stock camber rear (around 2?, dunno) and more than -3deg front. My car really seems to like it.

[bgregg]

My track tires:
relative to stock, I went almost 0.4" taller in front and almost 1.0" taller in rear on track tires. And stock form is for front to be taller than rear by 0.3". So by going square I am getting a lot nearer to the original intentions of stock. I have deviated pretty far from that with my much taller rear than front.

So I am leaving the staggered idea behind in the dust, and moving to all 235/40-18. Unless I made a math error. In my case, going all 245/40-18 on first attempt was an "internet mistake" where I read tire/wheel forum and thought it was the way to go. I now think all 235/40-18 is the way to go instead, based on my own actual fitment experiences. This is still a significantly taller tire than stock was.

I am talking R compound tires specifically. Street tires I am keeping exactly stock configuration.