MR (Megan Racing) Coilover Review

Installed MR coilover's yesterday and went on an 80 mile drive that included a wide array of roads, from freshly paved highway to highway and local roads under construction and some nice twisties.

Settings.

Length: Just about maximum length (as specified by MR and Boostjunkie) at rear. The rear lower part of the shock has a hole that indicates the minimum 30 mm thread engagement. Front: 17", measured (as Boostjunkie did) from top of spring plate at the top to the bottom of the strut tube.)

Ride height: The following was the stock ride height, measured with 33 psi in the tires and a quarter tank of gas and measured at the center line of the wheels from the ground to the edge of the fender cut-out.

front right: 26 11/16"

front left: 26 3/8"

rear right: 26 5/8"

rear left: 26 5/16"

Interesting that the right was higher than the left.

The following are the new ride heights, measured this morning after 80 miles of driving:

front right: 25 5/8"

front left: 25 1/4"

rear right: 25 5/8"

rear left: 25 13/16"

Again, right side is higher at the same coilover height.

It appears that stock ride height is not obtainable at the rear; in my case, average drop from stock is .75"

Spring preload: I kept this at the factory settings.

Dampening: With a stated 32 stops, my initial settings are 8 clicks up from full soft for the front and 10 clicks up from full soft at the rear.

Driving impressions:

All driving done so far was with my family of four, no lightweights, at about 750 lbs total.

Noise: Slightly increased road/tire noise, probably due to the hard pillow ball mounts.

Vibration: No noticeable increase.

Road feel/bump transmission: Noticeable increase, probably due to the higher, non-progressive spring rates. You know what the road is doing. In general, this is not unpleasant, but it definitely is less "silky". My wife, riding in the back seat, called it "more truck-like." On the other hand, both my sons managed to fall asleep for portions of the trip.

Vertical control over bumps and dips: In general, good, though we did not encounger any large radius humps or dips that I took at high speed. Definitely "tighter" than stock.

Lateral control/cornering/roll: Substantial, nice improvement. Flatter, tighter, more confidence inspiring. Definitely best enhancement/smile inducer over stock. With family in tow, lateral G's were kept relatively low, so this requires more exploring.

Sharp edged transitions: Traveling at about 35 mph on a back road, we encountered a hard edged vertical transition of about 2" at a saw-cut pavement transition. WHOMP! The front suspension crashed loudly (though not too hard) onto its bump stops. Rears were OK and did not duplicate the hit, perhaps because of their higher spring rate. In 3200 miles of driving, that has never happened with the stock set-up. Near the end of our trip, at 30 mph, the right front fell into a recessed manhole cover in a newly paved road. A slightly quieter WHOMP into the front bump stop.

These two incidents were enough to have me hit the brakes before going over a saw-cut pavement transition two blocks from my house.

I think this un-civilized behavior over fairly modest sharp edged transitions exposes the Achilles heel of coilovers; reduced suspension travel. The high energy levels and corresponding high spring compression velocity imparted by the short time-frame of a sharp-edged hit can not be handled by the short travel and linear nature of the springs and dampers. Even though softer, the longer travel and progressive nature of the stock set-up handle this much better.

I have not been able to find any travel information for any coilover, but looking at the strut/shock design, spring length, and coil spacing, it is short and substantially less than stock. Does anyone have this info? Has anyone measured the stock suspension travel? The coilover springs being linear doesn't help. Looking at the MR coilover construction it looks like a longer spring with longer travel could have been incorporated.

Can anything be done to improve this behavior? Are longer springs available for the MR coilover? Could the dampers handle a longer spring?

Unfortunately, improving our New England roads is not an option.

Speaking of damping control... Can you reach the rear dial? I took my floor panels off today and realized that it's going to be tight access to the dial unless I remove the side panels. I would rather not remove the side panels...

I took a look at the nuts that were provided with the MR coilovers. There are serrations on the integrated washer. I believe that this is the same as the stock nuts.

However, there is one thing that I am concerned about that I didn't realize until I read your posting... the nuts are not SAE grade 5 nuts like the OE. Take a look at the pictures. There are no SAE grade marks on it. I might stop by the dealer and buy some stock nuts. Can't be too careful.

http://commons.wikimedia.org/wiki/Image:Nut_marking_SAE_Grade_5.png

Thanks for the review rayu. I found it thorough and candid. The impact harshness you spoke of is more endemic to the spherical bearing top hats (pillow balls) than to the shortened stroke dampeners, which actually allow for more compression travel on a lowered suspension. It is part of the trade-off that is made for the sharper response and improved steering feel that you gain from the pillowball top hats. Obviously, different people will have different stands on this compromise, but if you think about it, the situations in which you will get a truely "uncivilised" response are pretty rare. Big, sharp edged bumps will be accompanied with a decent "thwack" when the compliance of rubber bushings is removed, but in almost all other situations the car is far more fun to drive.

I do not know if this is possible, but if you do not need the camber adjustability of the included pillowball top hats, you might want to try refitting the stock top hats. That will improve the impact harshness. If you feel that the front suspension is truely bottoming out, try adding a bit of preload, something like 1/4" or so (80-100 lb/in). That will extend the amount of compression travel. It will also have the side effect of sharpening your turn-in response as the front springs will be less apt to compress as the wheels are turned. The flip side of the coin is there will be a touch less extension travel, so edge drops will be a tiny bit harsher and responsiveness to ripple type bumps will be diminished slightly. I would suggest adding a similar amount of preload in the rear to help with the ride height, which is will also help the rear stay out of the bumpstops.

If you would like different spring rates, I do have some spares and I could easily work out a swap with you, but I'd say try out the easy adjustment changes first. Hopefully these suggestions will help you acheive the ride/handling compromise you are looking for within the constraints of the hardware. I'd also suggest an alignment after you get things set up to your liking, as this will ensure proper tire wear and optimal handling. With respect to the alignment, have the shop set you up for at least 1* of negative camber in front, and zero toe all the way around.

Please let me know if I can help out in any other way.

Having rubber bushings in the top mount v. spherical bearings has nothing to do with if it's going to hit the bumpstops or not. While I believe spherical bearings are utterly useless for the rears as they are shocks, not struts, we are talking about the fronts.

Bottoming out the suspension is a combination of:

o Not enough suspension travel

o Front spring rate too low

o Inappropriate shock valving

Warren

Having rubber bushings in the top mount v. spherical bearings has nothing to do with if it's going to hit the bumpstops or not. While I believe spherical bearings are utterly useless for the rears as they are shocks, not struts, we are talking about the fronts.

 

Bottoming out the suspension is a combination of:

 

o Not enough suspension travel

o Front spring rate too low

o Inappropriate shock valving

 

Warren

What I was telling the OP is that what I believe he is feeling is NOT the car bottoming out, but rather just the harshness from sharp bumps that is now more directly transmitted because of the spherical bearings.

I agree that pillowballs on the rear coilovers are unecessary. I believe they are used as a matter of production expediency more than anything else.

Had the car out on Sunday with no passengers, traversing some of the same roads I had taken on the premiere trip on Saturday. The MR coilovers definitely liked the lighter load. The sunken manhole cover that garnered a loud thwack with the loaded car generated a substantially more muted response at about the same speed. I went back and looked at the sunken manhole cover and found out that while the 3" or so drop was steep it wasn't sharp edged.

This makes sense in that the lighter car has more travel available and the forces the suspension has to deal with are lessened.

I also traversed a speed bump table (angled transitions with perhaps a 10' flat) at perhaps 25 mph. This gave me a taste of the vertical launch, but not having driven this with the stock suspension it was hard to tell if the MR coilovers handled it better or worse.

It is possible that what I experienced was not the front suspension bottoming out but some other unrefined behavior, perhaps a combination of shock valving unable to take the fast spring acceleration caused by the sharp edged hit along with the rigid pillowball top mounts.

rclark0032, I'll post a copy of my review in the reviews section. Makes sense and makes it easier to find.

I concur with rayu's review. I just installed a set of BC BR inverted coilovers w/ 5/7kg springs, almost identical to the MRs. I hope mine soften up a bit, but right now they are unacceptably harsh over sharp-edged bumps. Other than that, even with the swaybars disconnected for corner weighting the car is a go-kart. At speed, the suspension works very well. Around town, it communicates tons of information, too much for me. I'll give it a couple of months to get used to it before swapping suspensions.

While an old thread, good information.

I concur with rayu's review. I just installed a set of BC BR inverted coilovers w/ 5/7kg springs, almost identical to the MRs. I hope mine soften up a bit, but right now they are unacceptably harsh over sharp-edged bumps. Other than that, even with the swaybars disconnected for corner weighting the car is a go-kart. At speed, the suspension works very well. Around town, it communicates tons of information, too much for me. I'll give it a couple of months to get used to it before swapping suspensions.

 

While an old thread, good information.

whats your stiffness at?