Dinan or Eibach -Ready to pull the trigger but need advice.

Jimmer wrote

So are you suggesting the rear should have more camber then the front? You mentioned Lucid dialed in back from 1.75 to 1.5 due to heating the inside more. So should I start with 1.5- degree in the rear? If so what up front? Only 1.25- degree? That doesn't seem enough..

I felt the car was loose on my first day on the track after the alignment and then measured tire temps when I got in, and the insides were indeed hotter and the rest of the tires were even with -1.75 in the rear. You could actually see the wear. Unfortunately, I did not document the temps that day and it's all mixed up in my mind right now since I was measuring a bunch of other temps, so I can't say how much hotter the insides were running exactly, but putting that together with a loose end made me decide to have it dialed back to -1.45.

I have -1.95 up front with the Dinan plates, and I think that works great. It is questionable if you need more, but then we haven't seen anyone reporting running with more up front.

There is more discussion on camber settings for the track here:

http://www.m3post.com/forums/showthread.php?t=258968

dcstep wrote

As for the lightness at the rear, we experienced lightness in the rear at VIR. It could happen in the uphill esses and the corner right before Oak Tree. In both cases the solution was to be on the gas. For the esses we'd slow down at the entry of the 2d set, from around 120 down to around 110 mph, and then accelerate all the way up the hill. If you thought about lifting in the middle you were toast. The turn before Oak Tree falls off camber in the middle and leads to a short downhill. It took faith to plant your foot there, but if you didn't you'd push out or if you lifted in the middle you'd get tail happy. Those were stock cars. Oh, if you're zinging at the top of 4th, then short shift earlier in the corner, perhaps way early.

I don't know if that's your answer, but it's worth consideration. More tire at the rear could also help a lot if you've got room.

The issue for me at the Glen was that you kind of need to do turns T2-T3-T4 without shifting since they are really back to back at high speed although I guess you could try to shift between T2-T3. Even if you did you'd be shifting into 4th from 3rd, and the sweeper the car felt unstable was T4, so short shifting into 4th wouldn't really work, but I guess you could try to short shift into 5th in between T2-T3, which would be slow. Just to illustrate what I mean, check out the hot lap in the latter part of the clip below. T1 is 90 deg and is taken in 3rd (7:25 in vid). As you approach T2, you can keep it in 3rd, but you'd catch the redline before the transition to T3 as you are supposed to floor it there pretty much all throughout 2-3-4 if you want to go fast. So, I ended up slightly short shifting into 4th before T2 and keeping it there. As you can kind of hear, I catch the limiter in 4th right around 7:48-7:49 and ride it for a second or two. You're going really fast coming out, and as you are saying, I wouldn't want to lift/shift without straigtening out with 6MT as I think the speedo is right around 140mph at that point.

Yeah, I see, pretty touchy through there. All those guard rails closing in make it seem even tenser.

I wonder if you could try two short-shifts to get up to 5th by your final shift and then compare your entry speeds onto the straight that follows. The toque curve is so good that you might do better in fifth at WOT than you think. It'll start a little slower, but you'll continue to accelerate through that period where you're against the limiter. An alternative is skip 4th and compare your speed at the beginning of the straight.

Dave

lucid wrote

I felt the car was loose on my first day on the track after the alignment and then measured tire temps when I got in, and the insides were indeed hotter and the rest of the tires were even with -1.75 in the rear. You could actually see the wear. Unfortunately, I did not document the temps that day and it's all mixed up in my mind right now since I was measuring a bunch of other temps, so I can't say how much hotter the insides were running exactly, but putting that together with a loose end made me decide to have it dialed back to -1.45.

I have -1.95 up front with the Dinan plates, and I think that works great. It is questionable if you need more, but then we haven't seen anyone reporting running with more up front.

There is more discussion on camber settings for the track here:

http://www.m3post.com/forums/showthread.php?t=258968

Thanks! So you are running -1.95 up front and -1.45 in the rear?? And it works good for you?

Jimmer wrote

Thanks! So you are running -1.95 up front and -1.45 in the rear?? And it works good for you?

Had two track days on it at those settings. So far so good. It's my DD, so I don't see myself going more aggressive than that at this point. Keep in mind that's with a staggered 265/285 setup on the track, and a staggered 255/275 setup on the road.

lucid wrote

Had two track days on it at those settings. So far so good. It's my DD, so I don't see myself going more aggressive than that at this point. Keep in mind that's with a staggered 265/285 setup on the track, and a staggered 255/275 setup on the road.

Thanks man! I'm really appreciating the advice. My car too is my DD including throughout the winter so can't go too aggressive but want to feel a difference on the track. Just gave the okay and springs are going on as well on Tuesday.

I'm on my stock 18's - 245/265 track and street. Think that will change the numbers a ton? Should I just be telling the dealer -1.95 up front and -1.5 in the rear? Toe, etc all stays stock?

I drove my DD 5.0 Mustang LX knotchback with zero toe. It was a rough riding car already, with lowering springs and Tokiko's super shocks, so I put up with the extra dartyness. I don't think it's worth it with the M3. The 'stang had weight distribution issues, so it was worth it in that case. Since the M3 doesn't really have turn in issue, I wouldn't be interested in doing it except on an all out track car.

Dave

I bought HR springs and haven't opened them. I've changed my mind and I'm going with Dinan. I have Macht Schnell spacers on my car and that made a big difference in the look with the stock springs. The .5 isn't much but it will do enough for me with the spacers.

Jimmer wrote

Thanks man! I'm really appreciating the advice. My car too is my DD including throughout the winter so can't go too aggressive but want to feel a difference on the track. Just gave the okay and springs are going on as well on Tuesday.

I'm on my stock 18's - 245/265 track and street. Think that will change the numbers a ton? Should I just be telling the dealer -1.95 up front and -1.5 in the rear? Toe, etc all stays stock?

If you are also running a staggered setup, then I think maxing out front camber with the Dinan plates is a good idea. My Dinan installer said it won't go beyond what I've got, and that turned out to be pretty good IMO. I've shared my observations regarding rear camber. You might need to play around to see what works for you and your tires. Based on my readings at the track, starting by maxing that out might not be the best idea. I don't remember the exact toe, but I think we might have gone close to 0 toe front and some toe-in in the rear.

dcstep wrote

Yeah, I see, pretty touchy through there. All those guard rails closing in make it seem even tenser.

I wonder if you could try two short-shifts to get up to 5th by your final shift and then compare your entry speeds onto the straight that follows. The toque curve is so good that you might do better in fifth at WOT than you think. It'll start a little slower, but you'll continue to accelerate through that period where you're against the limiter. An alternative is skip 4th and compare your speed at the beginning of the straight.

Dave

Yeah, I considered both of those possibilites, but as I've said, I am not sure trying to shift in the T3-T4 transition is a good idea. As you know, these videos make things look calm and under control, and things sure aren't as stable in person! I could try shifting up to 5th instead of 4th going into T2, but I suspect that would be slow, but worth a try...

lucid wrote

Yeah, I considered both of those possibilites, but as I've said, I am not sure trying to shift in the T3-T4 transition is a good idea. As you know, these videos make things look calm and under control, and things sure aren't as stable in person! I could try shifting up to 5th instead of 4th going into T2, but I suspect that would be slow, but worth a try...

Yeah, that's funny about "calm and under control". At those speeds everything looks like nothing's going on until....

My best lap at VIR looks so smooth except where I go over the curbs in the esses and that's only a little rumble in the audio. I'd missed an earlier apex just a tiny bit and used the curbs to straighten the track. There's a little chirp from the tires at the end and the audio doesn't catch my sigh of relief.

Dave

lucid wrote

The issue for me at the Glen was that you kind of need to do turns T2-T3-T4 without shifting since they are really back to back at high speed although I guess you could try to shift between T2-T3. Even if you did you'd be shifting into 4th from 3rd, and the sweeper the car felt unstable was T4, so short shifting into 4th wouldn't really work, but I guess you could try to short shift into 5th in between T2-T3, which would be slow. Just to illustrate what I mean, check out the hot lap in the latter part of the clip below. T1 is 90 deg and is taken in 3rd (7:25 in vid). As you approach T2, you can keep it in 3rd, but you'd catch the redline before the transition to T3 as you are supposed to floor it there pretty much all throughout 2-3-4 if you want to go fast. So, I ended up slightly short shifting into 4th before T2 and keeping it there. As you can kind of hear, I catch the limiter in 4th right around 7:48-7:49 and ride it for a second or two. You're going really fast coming out, and as you are saying, I wouldn't want to lift/shift without straigtening out with 6MT as I think the speedo is right around 140mph at that point.

Lucid, did you measure the front/near ride heights before and after? If the car is getting squirrelly - just enough to break your confidence when you're putting on the power at/after the apex to track out, then it could be rake. Pretty dramatic difference on my old E46 playing with rear ride height and spring rate. If the dinan springs change the rake of he car, especially after the weight is transferred to the rear under acceleration leaving the corner, then I can see the effect being a change in the stability of the car.

Putting shorter springs on a well dialed in car is likely to result in some loss of ultimate performance unless a lot of time and thinking goes into the new spec. The current suspension spec was probably dialed in after hundreds or even thousands of track hours. Dinan probably spent the most time thinking about the product, but I doubt they spent that much R&D time on a track at over 9/10ths hour after hour making small tweaks here and there.

jml wrote

Lucid, did you measure the front/near ride heights before and after? If the car is getting squirrelly - just enough to break your confidence when you're putting on the power at/after the apex to track out, then it could be rake. Pretty dramatic difference on my old E46 playing with rear ride height and spring rate. If the dinan springs change the rake of he car, especially after the weight is transferred to the rear under acceleration leaving the corner, then I can see the effect being a change in the stability of the car.

Putting shorter springs on a well dialed in car is likely to result in some loss of ultimate performance unless a lot of time and thinking goes into the new spec. The current suspension spec was probably dialed in after hundreds or even thousands of track hours. Dinan probably spent the most time thinking about the product, but I doubt they spent that much R&D time on a track at over 9/10ths hour after hour making small tweaks here and there.

Good point jml, but the suspension was stock when I was at the Glen (the video I posted above). I suspect it simply and mainly has to do with any stock car beginning to generate lift at those speeds.

lucid wrote

Good point jml, but the suspension was stock when I was at the Glen (the video I posted above). I suspect it simply and mainly has to do with any stock car beginning to generate lift at those speeds.

Needs 295 rubber in the back

jml wrote

Needs 295 rubber in the back

Already on 285 slicks!

lucid wrote

Already on 285 slicks!

Thats what we call "not f**king around"

Cheers,
e46e92

e46e92love wrote

Thats what we call "not f**king around"

Just goin' that much faster when all hell breaks loose. Fortunately, our man Lucid knows what he's doing.

Dave