Are thrust bearings needed when using the Allstar coilovers?

 

I guess it boils down to personal preference. I do.

If your running isolators on the top likely you could do without.

 

Got most of my stuff in the other day but definitely lost the lotto on the springs, only 5" springs... Waiting on QA1 7" 550 front, 7" 350 rear for my NA HDs.

Sounds like stock valving can handle that but not necessarily ideal. Is re-valving worth it? To my knowledge my HDs have about 10k miles since they were rebuilt.

 

10k miles isn't many. They'll be fine for a good while.

 

OP, ordering part# iss-310-3019-50 from summit
"Integra Speedthane Shock Bumpers 310-3019-50"

Your invoice lists as quantity 2 ordered.
Does that cover all four corners?
SummitRacing lists them priced individually.
thanks

 

This was sort of covered earlier but it seems that no conclusions were drawn really. Seems like it would be good to layout what people can expect from the different shocks available for this project.

FatCat has some dyno plots:





And also does a video compare:

The problem is, the consensus of this thread seemed to be that the MSM dampers were the best choice, while FatCat's video basically says the MSM's are terrible. Seems to have a reputable site, and I don't really want to derail thread into a discussion on how well his damping strategy works (anyone have his re-valves?), but it seems important for someone picking which shock to run in their conversion.

Also, would be cool if we could put together a table of bilstein's vs application (NA, NB, etc) listing what ride height is possible for X size top hat spacer...

 

I am trying to figure out what kind of bump stops I should order. (2001 no more than an inch lowered)

Basically I am trying to choose between long and soft or shorter and harder.

Anybody have a good handle on what sizes and hardnesses work best?

 

Ideally, I think you would want front and rear bumpstops of the same relative stiffness as your springs, so if you're running 500/350 you'd want a front bumpstop that's 43% stiffer than the rear, and sized to engage at the same cornering Gs, which requires knowing your corner weights, spring preload, and motion ratios. Then comes the hard part, which is finding bumpstops that fit your specs, or having them custom made.

Or you can just buy some Honda bumpstops for $5/corner and call it a day. The part numbers are somewhere in this thread.

 

Honda bumpstops FTW.

 

I guess if I want any real advice I should supply more information. This is my thinking for a daily driven 2001 that will see occasional autocrossing:

I have been racing a long time and I have a separate Rx7 race car for my hard core needs. It is still nominally street legal and it does not feel too stiff over bumps but it does feel like a table with only three legs touching the ground over some road undulations. I don't want my Miata to feel that way. I will do some autocrossing but I don't care about trophies, I just want to be mildly competitive. I don't really want to lower the car much but I do not like the large wheel gaps on my stock car.

With that goal in mind I am planning on buying a set of B8 shocks (the shorter ones) and the Amazon coilover kit posted earlier in this thread because it comes with 7 inch 350 pound springs plus a set of ebay 7 inch 5 KG (280 pound) springs for the rear. That will give me rates following the "flat ride" theory from Fatcat Motorsports at pretty close to $100 plus about $500 for the shocks.

Regarding sway bars, I will start off with my stock setup. I don't know the exact math but since the rear suspension roll center is higher than the front suspension roll center, I believe that the roll stiffness will shift towards the rear as the spring rates go up. (suspension roll centers are not addressed at all on Fatcat Motorsports worksheet) I am keeping the front end spring stiffness enough more than the rear spring stiffness so that at 350/280, the car should not be getting too tail happy. I can go with the RB front sway bar and stock rear bar to bring it back into balance if I am wrong about that. (or disconnect the stock rear bar if I am still feeling cheap)

When I get to the bumpstops I get a little confused. My first thoughts were to just get long soft bumpstops and ride on them all the time. The spring rates are low enough so that the increased spring rate probably won't be too bad and since the car is always on the bumpstops, the transition to progressive rates would be smoothest. Eventually I found a comment on Fatcat Motorsports website saying that long bumpstops would reduce suspension travel. My current thinking is that I will buy the soft 75MM bump stops, cut them in half, and put the fat end on the front and the cone end on the rear. (am I really so cheap that I would not just buy 4 shorter bumpstops? - I didn't see them any cheaper than $18 each)

What do you-all think of that plan?

 

Dont get the "shorter" shocks, the bodies are the same length and they just have internal droop limiters installed.

 

Honda part number 51722-SR0-003

They're $6 apiece and something like 57mm long.

 

OK thanks, I guess I'll get the B6 shocks and a set of 4 Honda bumpstops and trim them down to about 35mm.

I doubt that I will find 350/280 to be too stiff since everybody else here seems to be going straight to 450 or higher. If I think it's too soft, I can always pick up a pair of cheap Ebay 8KG springs and switch to 447/350 with the same sway bar options I mentioned above.

The only downside I see is that I get the impression that when you are working in the 250-350 range, 8 inch springs with a lower sleeve would probably work better but that would probably run the cost up a few hundred.

 

You wont be able to go much lower than stock with such low spring rates.

 

I'm happy with my setup so far, but given that I'm running on horrendous bump stops, I've been thinking about removing my NB top hats and doing a DIY pipe extension on them in order to stay off the stops. I don't much care for the way ISC hats mount the shock and would prefer to keep the OEM bushings in there. There's a lot of people doing this in the Honda world it seems, but not much info on it for Miatas.


Not my picture, but a Honda extended top hat.

I'm running 450/300 7" QA1 HT springs, NB Billies, 12.75F/13.25R ride height and will probably not go a whole lot lower than that. I think I could get away with only extending the rear hats, but am not sure how much extension would be ideal for my ride height. Then again, the shitty shock savers are in the front and I'm running stock NB stops in the rear, so maybe I ought to do both.

Thoughts?

 

At this point I am trying to choose between 450/350 or 350/280. I don't think I want to go stiffer or softer than those two choices.

As I said, this is a daily driver. I want fun/fast street handling and respectable but not serious autocrossing. (considering New Jersey/NYC area road quality)

If I choose the wrong one, it's only about $50 to buy the other spring pair. It's probably easier to recognize if the car is too stiff then if it's too soft.

 

350/280 will help keep you off of the bumpstops on a street car if you allow yourself enough travel before you get into the bumpstops. Otherwise it will crash into the stops just like stock does and you will have gained little.

 

At some point you start to reach the limit of the travel for the control arms. they will impact the chassis/mount.

You need to make sure you stay under that.

 

Exactly my concern. I also don't want to end up with no extension travel left in the shock. It'll have to end up with me under the car checking for clearance, but I don't want to reinvent the wheel if someone can give advice for my ride height and available travel.

 

If I remember correctly, the limit is somewhere in the 11" ride height range for the fronts. I think you can figure it out by putting the shock in without a spring, then set the ride height using your floor jack. Mark that, then measure the travel left before impact. Consider that with your bumpstop and the amount of compression travel you will have in the shock with extended hats. I might have missed a step here, its been a while since I have done travel measurements. Now-a-days I am lazy and let 949 do it for me.

Depending on how much travel is in your bumpstop, you will want to stop before impact + some more for safety margin (I am thinking for particularly sharp bumps).

I would avoid being that close to the limit of travel though, at least not without a lot of testing.

I am not sure how you plan to keep the stock bushings/setup in place, but add in the extension. I have never seen the ISC top hats in person (or the instructions), what do they do differently than stock?