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

AMPowerJ wrote

Well I ordered the Dinan spring package today and I also purchased the front camber plates. Figured while I was doing it I may as well go all out. Thanks for the advice folks. I will post pics in a few weeks once everything is installed.

Congrats !
You'll definitely notice a drop. It's subtle but it's there. Now when I look at my car I don't cringe at the height as before. It still could be a little lower but the feel/performance is much better. The ride feels a little firmer and more controlled. Without pushing the button on the EDC the car will feel sportier and in sport mode the car will feel tight.
Good luck

I think that BMW will limit the future drop in order to maintain the ride. You can drop further, but you'll lose ride quality.

Dave

rav7ks wrote

OK if BMW drops the car why do they only drop 0.4inches. Well because they are probably onto what Dinan has been doing with their spring set. With the stock setup, the max allowable drop without compromising performance likely ranges around .4-.5 inches. I bet they have shaved bumpstops etc like Dinan and a higher spring rate. This only confirms what Dinan has been stating.

I am pretty sure the Dinan setup does not utilize "shaved" bumpstops, and uses another bumpstop suitable for the application instead. Shaving a bumpstop is not the best thing to do as the stiffness of most bumpstops increase with compression, and by just shaving them, you'd be messing that and the overall stiffness up.

Ok
Your right they have shorter bumpstops that replace the stock ones.
Others here try to reproduce that by shaving their bumpstops when installing H&R's etc.

Do we have a final verdict on this discussion?
I'm reading more and more about the Dinan set-up, as I want to keep my M as pure as possible with a tad bit of cosmetic and performance gain.

I'm not going to be tracking the car, so is it in my best interest to save a few hundred and get the eibachs or does Dinan's revised bumpstops and suspension travel theories really warrant the extra money?

HREM3 wrote

Do we have a final verdict on this discussion?
I'm reading more and more about the Dinan set-up, as I want to keep my M as pure as possible with a tad bit of cosmetic and performance gain.

I'm not going to be tracking the car, so is it in my best interest to save a few hundred and get the eibachs or does Dinan's revised bumpstops and suspension travel theories really warrant the extra money?

Well, I haven't driven the HR or Eibach solution yet, but I've read some negative comments in these forums about ride quality. Hopefully I can find a Denver-area car with Eibachs or HR and do a comparison.

I CAN assure that 99% of the enthusiast driving population is going to be pleased by both the performance gain while maintaining ride quality that the Dinan offers. The cosmetics of the Dinans are positive, but minor. I'm very confident that if you're looking for performance gain while maintaining ride quality that you'll be very pleased with the Dinan kit.

Anyone considering tracking or autocrossing should add the Dinan camber plates to the package, since the stock towers don't give enough negative camber up front. Don't waste money by doing it two steps.

Dave

I have also read negative feedback on ride quality of the H&Rs. For this reason they are simply not an option for me.

I've heard good things about the Eibachs however.
I'm still very unsure about the two. I know the Eibachs are a pure cosmetic upgrade and the dinans offer a little more....ahh tough decision.

What actual set-up are you guys all using with the Dinan camber plates. The dealer is re-installing mine as we figure they screwed the alignment after and that made the car loose.
I'm not sure if I'm going to add the Dinan springs or not right now. The dealer does tho want to know what setup I want so they don't screw it up again. What do I ask for? As much camber as possible up front (what degree is that?) and then more in the back (what degree is that?).

This is my daily driver and I use it year round so don't want to go crazy but I track the car on a regular basis. I do NOT have EDC.

Thanks so much in advance for any help guys.

HREM3 wrote

I have also read negative feedback on ride quality of the H&Rs. For this reason they are simply not an option for me.

I've heard good things about the Eibachs however.
I'm still very unsure about the two. I know the Eibachs are a pure cosmetic upgrade and the dinans offer a little more....ahh tough decision.

I would like to know on which facts you based your opinion on...

^-- they are both cosmetic.... Simply switching to a slightly stiffer spring isn't going to do much for you. If you want performance you must take into account the entire geometry of the suspension.

J08M3 wrote

^-- they are both cosmetic.... Simply switching to a slightly stiffer spring isn't going to do much for you. If you want performance you must take into account the entire geometry of the suspension.

I disagree. A stiffer spring gives more control of jounce and rebound, so long as it's still matched with the shock, as is the Dinan. It's a matter of degree, however. Adding negative camber will add more performance than merely stifffening the springs, but doing both is even better.

Of course, spring and damper choice is largely dependent on usage. For street driving, the Dinan improves ride by eleminating any ambiquity in the "Normal" setting with EDC. Center of gravity reduction is small, but that, combined with the stiffer spring, does indeed reduce body roll.

Dave

J08M3 wrote

^-- they are both cosmetic.... Simply switching to a slightly stiffer spring isn't going to do much for you. If you want performance you must take into account the entire geometry of the suspension.

So the progressive and stiffer part of the springs performance is also cosmetic? Come on, we are not talking about that suddendly the car will have some radical improvement in handling after installing springs, but there are performance improvements albeit subtle in a combination of a progressive rate and a stiffer compression/rebound springs nicely matched to OEM shocks. Things like less squat while accelarating and less dive in in hard braking. I don't know how much less, but for sure I can feel it in my car.

The same applies in reverse... just swapping springs can degrade performance, by being unmatched to the OEM shocks so the handling becomes unstable.

I think that in these forums only radical changes in whatever is discussed are the only things that matters and everything else is dismissed as irrelevant...

Jimmer wrote

What actual set-up are you guys all using with the Dinan camber plates. The dealer is re-installing mine as we figure they screwed the alignment after and that made the car loose.
I'm not sure if I'm going to add the Dinan springs or not right now. The dealer does tho want to know what setup I want so they don't screw it up again. What do I ask for? As much camber as possible up front (what degree is that?) and then more in the back (what degree is that?).

This is my daily driver and I use it year round so don't want to go crazy but I track the car on a regular basis. I do NOT have EDC.

Thanks so much in advance for any help guys.

Where did he set the rear camber? Most of us are going 1.5 to 1.75-degrees negative. If he set the fronts near -2-degrees and left the rears at 1.25-degrees, that'd likely feel loose.

Lucid tried 1.75-degrees and was heating the inner edges more than the rest of the tire, so he went back to 1.5-degrees. He'll probably chime in about the handling, but I have to think that the flatter contact patch at the back has helped both acceleration and stability.

I'm adding the camber plates next week, so I've only got 1.25/1.75-degree front/rear right now, but I'll move the front out to near 2-degrees when I add the camber plates next week to my Dinan spring kit. Lucid has the kit also.

Why are you in doubt about the springs. Ride-wise and cosmetically it's a no-brainer. If cost is an issue, then the camber plates are the best first step.

Get a computer readout before and after the realignment. It might even still be available from your last algnment. If you could tell us the settings then we might be able to be more specific. I wouldn't be surprised if he didn't max out your front camber and not even looked at the rear.

Dave

Technic wrote

So the progressive and stiffer part of the springs performance is also cosmetic? Come on, we are not talking about that suddendly the car will have some radical improvement in handling after installing springs, but there are performance improvements albeit subtle in a combination of a progressive rate and a stiffer compression/rebound springs nicely matched to OEM shocks. Things like less squat while accelarating and less dive in in hard braking. I don't know how much less, but for sure I can feel it in my car.

The same applies in reverse... just swapping springs can degrade performance, by being unmatched to the OEM shocks so the handling becomes unstable.

I think that in these forums only radical changes in whatever is discussed are the only things that matters and everything else is dismissed as irrelevant...

I agree with both you and dcstep. Stiffer springs can help performance. Especially (or pretty much only) if matched right to the shocks. However I don't think you'll be seeing/feeling any improvement with either the Dinan or Eibach as my post was referring too. I haven't driven the Dinan yet, but I can tell you with my car having the Eibach (even though I don't have track times to compare) there is no way it handles any better than OEM, and wouldn't surprise me to see a slightly slower lap time on a track. If you want improvement you will need a good set of coilovers where both components are matched.

That being said, either choice of spring will be fine for the street, and unless you're a serious track guy I wouldn't worry about either choice and performance changes.

The only meaningful observation I can make at this point about the performance of the Dinan springs is that they did not make me go slower!

Seriously, it's pretty hard to judge objectively. At Limerock, my laps times were just a bit slower (half a second maybe) after the install, but I think that had to do with too much negative camber in the rear, tires, and how I was driving that day (didn't push it as hard for whatever reason). Whatever improvements that were associated with the slightly stiffer springs were probably negated by the other factors.

The other thing is that I believe the performance differences will be rather subtle to the extent that you probably need a professional driver to demonstrate them consistently. In other words, I highly doubt that one can shave a second a minute off a lap time just by installing Dinan springs.

I would be concerned about what a very agressive spring swap might do without messing with shocks though. Although I have no proof of any kind, I would be concerned that might reduce performance.

I got the Dinan springs because I simply enjoy the slightly stiffer suspension, and they don't detract from the ride quality. And they do a subtle job in closing the fender gaps, and that's a purely subjective call. I will share some observations again after I use them more on the track. I'm going to NHMS this weekend, and that's a track I know fairly well, so I might be in a better position to comment, but again, I didn't have slicks on the car last year, so won't be an apples to apples comparison.

If you really want a major performance gain, go with a quality coilover system like the Motons, but that means you need to know how to adjust it or know someone who does.

J08M3 wrote

I agree with both you and dcstep. Stiffer springs can help performance. Especially (or pretty much only) if matched right to the shocks. However I don't think you'll be seeing/feeling any improvement with either the Dinan or Eibach as my post was referring too. I haven't driven the Dinan yet, but I can tell you with my car having the Eibach (even though I don't have track times to compare) there is no way it handles any better than OEM, and wouldn't surprise me to see a slightly slower lap time on a track. If you want improvement you will need a good set of coilovers where both components are matched.

That being said, either choice of spring will be fine for the street, and unless you're a serious track guy I wouldn't worry about either choice and performance changes.

Perhaps the Eibachs are too stiff and don't match the shocks. Lucid is tracking with the Dinan setup and I'm doing autocross and we're both experienced drivers. My butt tells me that the Dinan's a significantly better than stock, even without camber plates.

It's funny that you mention coilovers. My main competition at my club AX is a young buck with a 400 hp Dinan 135i with coilovers. I beat him seven out of eight laps and he nipped me on one. He'd made the same mistake as me, doing the springs without the camber plates. He neither of us had enough negative camber to fully take advantage of our springs. His CG was quite a bit lower than mine, but it wasn't giving an advantage. Maybe we'll trade cars for a lap or two one day, but coilovers didn't seem to be a big advantage in that application. (We'll both have camber plates at the next event).


Dave

Here's how the Dinan spring kit without the camber plates looks in action. You can see there's a good bit of lock on and the car is accelerating in about the middle of 2d at WOT, just before pushing. The roll is well under control and the geometry looks very good for a stock set up. Clearly more negative camber will be a big plus in this type of driving. (Image used with permission of photographer Cliff Lawson):

dcstep wrote

Here's how the Dinan spring kit without the camber plates looks in action. You can see there's a good bit of lock on and the car is accelerating in about the middle of 2d at WOT, just before pushing. The roll is well under control and the geometry looks very good for a stock set up. Clearly more negative camber will be a big plus in this type of driving. (Image used with permission of photographer Cliff Lawson):

Nice pic Dave!

Plate induced negative camber up front is the first thing one notices. And it is up to the driver to put that to effective use. Some people might never push the car hard enough turning in, so they might not be able to tell. The springs are more subtle IMO.

The mechanic who did my install, who is well respected and very experienced, but not a track driver, could immediately tell the effect of the camber plates during the test drives. He couldn't tell the stiffness difference though. When I drove it for the first time after the swap, the stiffer springs were very noticable to me, but maybe it is because it's my car and I know it well.

My main concern with the handling at this point is the way it begins to get loose at high speed sweepers. By high speed, I mean 90+ mph. At the Glen, it really was not comfortable as I was coming out of the esses sitting on the limiter in 4th on the exit (I did not dare shift although the last one is a large radius turn). But I guess that has more to do with the lack of downforce more than anything else.

Also, you might be seeing the springs and observing their effects in a different light during autoX at slower speeds and sharper steering inputs.

I have the H&R's and I can tell you right now the rebound is pretty damn off unless you're in "sport" mode which is the non-dynamic shock mode which sucks because you lose that cool feature.

MrHarris wrote

I have the H&R's and I can tell you right now the rebound is pretty damn off unless you're in "sport" mode which is the non-dynamic shock mode which sucks because you lose that cool feature.

Evidently the H&Rs are harder than the Dinans. I think that the Dinans are best matched on "Normal". There's ok on "Sport" but I was slower in the AX on "Sport".

Dave

lucid wrote

Nice pic Dave!

Plate induced negative camber up front is the first thing one notices. And it is up to the driver to put that to effective use. Some people might never push the car hard enough turning in, so they might not be able to tell. The springs are more subtle IMO.

The mechanic who did my install, who is well respected and very experienced, but not a track driver, could immediately tell the effect of the camber plates during the test drives. He couldn't tell the stiffness difference though. When I drove it for the first time after the swap, the stiffer springs were very noticable to me, but maybe it is because it's my car and I know it well.

My main concern with the handling at this point is the way it begins to get loose at high speed sweepers. By high speed, I mean 90+ mph. At the Glen, it really was not comfortable as I was coming out of the esses sitting on the limiter in 4th on the exit (I did not dare shift although the last one is a large radius turn). But I guess that has more to do with the lack of downforce more than anything else.

Also, you might be seeing the springs and observing their effects in a different light during autoX at slower speeds and sharper steering inputs.

AX is definitely very different from track. The negative camber, plus trail braking is a the fast way around a lot of really slow corners. Where you'd trail brake on maybe one corner on a fast track, you'll do it three or four times in one 40-second AX run. Getting on the power is much the same and some of the sweeping corners are the same. Apexes are as important to speed, but the consequence of a missed apex is not near so dire. In AX you have to concentrate real hard for 40 to 100 seconds, but in track it's 40-minutes and up and an equal level of concentration.

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.

Dave

dcstep wrote

Where did he set the rear camber? Most of us are going 1.5 to 1.75-degrees negative. If he set the fronts near -2-degrees and left the rears at 1.25-degrees, that'd likely feel loose.

Lucid tried 1.75-degrees and was heating the inner edges more than the rest of the tire, so he went back to 1.5-degrees. He'll probably chime in about the handling, but I have to think that the flatter contact patch at the back has helped both acceleration and stability.

I'm adding the camber plates next week, so I've only got 1.25/1.75-degree front/rear right now, but I'll move the front out to near 2-degrees when I add the camber plates next week to my Dinan spring kit. Lucid has the kit also.

Why are you in doubt about the springs. Ride-wise and cosmetically it's a no-brainer. If cost is an issue, then the camber plates are the best first step.

Get a computer readout before and after the realignment. It might even still be available from your last algnment. If you could tell us the settings then we might be able to be more specific. I wouldn't be surprised if he didn't max out your front camber and not even looked at the rear.

Dave

Thanks so much Dave.

I never got ANY feedback on where anything was set. I asked many times and got "it's probably around 1.25". I don't believe they touched the rear at all. I never did receive a printout. It was loose as hell and I actually spun off the track in front of all the students (first time ever off the track - not a great experience since I was instructing.....)

It is just the cost of the springs but probably going to take the jump. I really want a bit more handling on the track but need to keep it as a DD.

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..

Any other adjustments needed from stock (Toe, etc)?

Thanks so much for any advise guys. I'm quite green in this area and just know when the car isn't right, yet the dealer wants me to tell them what I want.