Suspension Considerations 245 Maxxis
 

My son almost has enough money for a 949 big grip kit.

Street tires will be 245/15 Maxxis. Hp will be 350ish with more on tap....Dialed down to Much less at the track!
As my son's driving ability grows we plan on adding Hoosiers at the track....No size considerations on that yet...Probably 245s
This is a Sunday sports car/ track car...Performance first!
This is not primarily a street car, but we prefer a car that feels like it knocks your fillings out over every bump.
Cake and eat it too so to speak!

700/400 Street: This seems a little soft for our tires and track goals? Thoughts?

800/400 Autocross: I don't really understand this setup? Loose for right foot rear end control? Doesn't seem a good place for us?

800/500 Race: This is what my son is leaning toward. My first instinct is that this setup will be overly rough on the street and a good choice for the track.
Given our horsepower objectives do we give up much rear wheel traction with this setup? A few here have run this setup on the street with seemingly no complaints?
Any thoughts here would be appreciated!


Cheers,
Jamie

I'm running 800/500. It's stiff but not uncomfortable. I also daily 350hp but I'm also running these on 15x9, not 10's

I wasn't sure if my fenders would house the 10's despite them being rolled flat. Still float a bit, but pretty forgiving even if not the fastest.

Sorry for the thread jack but I have a somewhat relevant question. How is the 800/500 over bumpy sections on the track? I'm guessing with good shocks it shouldn't feel rough or upset the car?

I have the 800/500 coaxial XIDA setup. It DEFINITELY can knock your fillings at the upper shock dampening clicks, and stiff sidewall tires. At full soft with stiff sidewalls it is bareable to drive, and you can feel the bumps easily, but they are not annoying enough to deter long trips. Full(or close to it) hard with stiff sidewalls, is uh, not adviseable on the street if you have lots of pits, cracks, and undulations. (In my opinion) It gets me sick pretty easily unless the road is smooth. Very bumpy, and actually took away from my driving confidence in a corner that wasn't smooth. I could take the same corners MUCH faster on blown oem shocks, just because the car didn't buck and bounce around.

I am currently driving on 185/60/15 (i think) snow tires, lots of sidewall, and very squishy at that. On full soft the ride is very similar to "oem blown shocks" feel, if that makes sense.

definitely dont get anything softer than 800/500, but make sure you get the billet coaxial mounts.

This is going on an NB so the 15X10s and 245s will fit a bit better.
I'm sure the 245/40/15 Hoosiers will require more serious fitting.
What do you mean by float a bit?

Thanks for sharing your experience!

Jamie

I read that the Xidas get hilariously firm at the stiff settings.
The blown squishy feel seems familiar! :)
Nice to know there is a setting if he wants to drive the car on an extended run!

I was planning on the coax mounts, 1.125 front sway, end links, rear sway (may leave it off depending on how it feels), extended ball joints, and perhaps the bushings that come with the 949 kit.
Also looking at other (Sadfab) bushings...not sure the best way to go there yet.

Thanks for chiming in!

Jamie

I would hold off on bushings until you can front the cost of the full sadfab delrin bushing kit. They also come with grease fittings. Do it once and do it right. I have the delrin setup, but I didn't drive my car for a few months as I was getting other things installed, so I can't really speak of the singular difference they made. (Other than all the suspension arms move around with almost zero effort.)

I might be wrong, but the extended ball joints can help with tire fitment, as they push the bottom of the tire out. I guess depending on your camber, they could also hurt clearance, if you didnt have enough camber.

I was able to get -3.4f/-2.8r camber without the ext. ball joints

"And now for something completely different"

I'm running 15x9 Advanti S1's with the 245 VR-1's. I've got 700/400 springs on Xida Gen2's (stock NB1 mounts, not billet) with a RB hollow bar in the front and no rear bar. The car is my DD but does autocross and limited track days. The front LBJ's are stock, but I do have RUCA's that are adjustable, so I can get as much camber in the rear as I need. I typically use as close to the 949 alignment as I can get. Also, my car is a 250-ish WHP car - so I'm down on power from your goals - but it's no slouch.

With the softer springs and with the Xida's on full-soft, the around-town behavior is pretty acceptable (not OE-plush, but not teeth rattling). At the autocross, the car is predictable and controllable (just a hint of lift off oversteer) - probably because I'm used to it more than anything. I've had others drive the car, and everyone has commented on how stable it was.

On the track I think I'm over-tired for the power I have on tap, and under-sprung for really aggressive driving. Someone with more skill than I would probably make disparaging comments ("tail-happy", "sluggish", etc), but I can manage not to embarrass myself, and can even stay with the "Big Boys" on-track.

There is no reason nor advantage to running the stiffer damping settings on Gen2 Xidas on the street. That is the whole point of adjustability. With softer springs and damping on the softer settings, the street ride quality is excellent. With full race springs and softer damping settings, the street ride is quite good, not harsh, just firm. You have to be willing to experiment with the damping settings to find a good street setting and a good track setting for your car and driving style. But yes, set full stiff on the street they'll suck. Make sure you are not below 4.25" pinch weld on track or 4.5" on the street. Much lower than that and you might be bottoming.

Can you comment further on what improvements the billet coaxial mounts give over the NB tophats? Will be making my XIDA order within a month or so (currently saving)

Friction reduction and that is a big deal. For more detailed info visit our website. There are links on the page to some more detailed Forum posts. But the most important is the picture of the shock which shows the mount on a different axis than the shock. There is no binding when the you have a bearing in there. With rubber bushings there is binding.

Havent seen that photo and I've dug through a large portion of the informational posts (unless I'm going crazy and just missed it). I assumed the coaxial mount was due to an axis misalignment. The friction makes sense. Might as well save for them it looks like as long as I'm at it

Thanks!
I think we are going to order the complete kit from 949 and leave the poly bushings off until he can afford the Sadfab bronze bushings.
We are adding so many other things that will add NVH....Poly with the Sadfab seems like a reasonable balance.
The car needs to go in for a basic alignment....I will get it checked out to see how much is on tap.

Jamie

Oh and definitely 800/500
54103 front bar, 14mm rear

I don't race but I do run 800/500 on the street on 15x9 6UL and 225/45 RS3s... I just want to give another vote towards completely tolerable. On full soft I have never felt the least bit uncomfortable.

Switched to Xida gen 2 approx November last year. 800/500.

Initially they were firm as all hell and I wondered if i'd made a mistake...I'm not sure on the realities of them "bedding in" but it sure felt like it. We actually got airborne on turn 1 bumps at pukekohe on the first 2 sessions after installation, things settled down after that.

They are now extremely comfortable on the road even at higher settings and fantastic on track. I recently ran an engine in via a 3 hour drive to our dyno tuners and had no comfort issues whatsoever.

Having never run that high a spring rate before (previously 10kg fr and 6/7 rear on on custom valved Koni Race) I was very concerned but it turns out to be a very good match to my 15 x9 Hankook ventus z214 and nitto NT01 semi slicks (Emilio knows what he's talking about.... who knew? :) )

In fact when I put the splitter/wing aero on it isn't enough. Even without aero and as I get faster again (lap times have been tumbling lately) could probably go up myself........Emilio can probably confirm or or not but if your running 10's with hoosiers you may want to go up 1 in the springs....especially if your prioritising track over street.

I also run Extended Ball joints and heavy front swaybar (24mm i think).

Thanks folks!
Looking like the suspension will be in the right direction!

We are planning on the standard flat ABS nose with a splitter with a Singular wing in the back. Probably 2 years out. Depending on how my son's driving is progressing, we were thinking it might be fun to look at Hoosiers then.
Long term plans, but I wondered how much down force was available and if spring rates would need adjusting.
Then I read Savington's S1 post and that he was looking for more front bar and maybe 1000 pound springs....with 200 tread wear tires!
It seems as if our setup has much more capacity/performance potential than I had expected!
245 Maxxis and great suspension FTW!

So...I have been looking at Keisler drop spindles.

Better bearings, 3 pounds lighter per corner, better geometry with the 4.25"ish ride height, sounds pretty amazing!
Then I read that they are designed around a longer shock, but you can go with spacers?
So the Xida's become some sort of a compromise?
Suspension is not my strong suit ......They seem like a nice product and I need a sanity check before I delete these from my brain.

Thanks in advance!

Jamie

Others with more specific knowledge on that product may comment but I think you are getting way ahead of yourself.

Mx5 with 949 big grip is one hell of a package (everytime we go out I am reminded) and finding the performance limits of that package alone will take a long time to complete, especially if you are coming from no driving, engineering or racing experience.

Sticking with a known, tried and true package with the amazing (sometimes argumentative :) ) community here AND 949 development behind you is a hugely compelling reason why I am working with the Xidas and the 949 / MT.net "formula". We are running one of (if not the) fastest track mx5's in the country and STILL have so much to learn and time left on the "board" .....drop spindles are a long way off our radar (if ever on it).

Unless you have a lot of experience, are finding a particular shortcoming or are having issues with the B grip kit I wouldn't get too far ahead of yourself.....(hopefully not sounding rude..)....just my opinion. Others may differ.

Track time is the ultimate performance improvement, build the car early, wait on some big ticket items and just get out there. the sooner the better. All the other stuff will come and become apparent when required.

I've had recent experience with something similar, V8R's billet lower control arms. Required weird spring lengths to keep the MCS adjuster (2.25" spring like Xidas) clear of the stock upper arm, lower "ball joints" (improperly loaded sphericals) bound at full droop due to improper angle, and for $850 they replace a part that has zero issues unless you run R compounds and like to hit curbs. And even then you could replace them once a year for about 8.5 years before they were more expensive than the billet arms.

You might look else where for chassis/suspension improvements before spending big money on the drop spindles.

mx5-kiwi,
I sort of figured as much, but while we were in suspension mode I wanted to cross all the t's and dot the i's so to speak.
The 949 kit and Sadfab bearings look to be a difficult to beat if not duplicate....The whole thing adds up to a package with astounding abilities. More than one could hope to start with in any other car.

Curly,
That sucks about the V8R arms!
With our target HP goals, and 245's, I was considering the V8R tubular rear arms to help with wheel hop.
Gha!

Thanks for the quick replies guys!

Jamie

hopefully ,my previous post wasn't rude......

I have a pet hate.

I see so many great cars sitting in garages waiting for this ultimate part or that ultimate part, finally years later (sometimes, often never) the car gets finished and is undriveable, unsuitable to the original intention or the person has just matured/grown up/changed direction in life or whatever and the car is relatively quickly just sold, more often than not as an incomplete project. My faterh gave me some great advice (that i learned the hard way too...) NEVER take your car off the road, do each project as its own thing and do your utmost to keep it drive able, going etc.

Almost always these cars could have been out there on track, cruising or whatever long sooner had the person just gotten on with the core focus of getting the car going. Especially now with the internet and the huge temptation of unreal variety of parts, opinions etc....

The fact is, driven well, a basic non turbo miata on 7" rims, average suspension okay tires can thrash a lot of cars on track.

Our car is now pretty well setup and with some of the nice parts from around BUT we have been driving and enjoying it while it got there the past 4 years.....won awards, placed high in our series, made friends had amazing experiences and most importantly learnt what was actually required and not what was perceived to be required...frequently quite different things.

Don't let xidas, drop spindles, 275 hoosiers, 15x10 6uls or whatever put you off getting the car going and drive it, race it etc.

If you buy second hand and wisely, the parts you get now to just get going, will be worth the same as they will in one year when you can sell them and upgrade etc.

Once again just a perspective from my own, getting out there and doing it viewpoint...if the build itself IS the project (as it is for many) ignore everything i just said :)

I appreciate people taking the time to comment!
You are going to have to do a lot worse that that to offend me!

Yes, it is about the build. This is a father son project.
It is also about creating a driving experience for him.

I was ready to forget about the spindles, but I thought I would ask before bailing out.
I would rather ask about a bridge that might be too far than spend the money and make a stupid mistake.

I am well aware of Emilio's suspension and development efforts....Also aware of the outstanding performance and value.
Nowhere in the many builds I have been a part of has there been a, here take this, bolt it on your car, tune it at the track and be a contender....For $3000.00 yet!
Unbelievable.

The plan for my son is seat time...as much as he can handle and afford....I will probably help there...The build...Not so much!
He attends a beginner track course some time soon, then a few weeks after that he has 5 days of formal instruction plus a 2 day stint with an serious racing buddy....likely on stock wheels and suspension.
The idea is to keep him at the track building his driving foundation for this year and probably next...While not picking up any bad habits from me!
Professional instruction/lessons mixed in as much as he can afford.


Jamie

Sounds great, your son is very lucky! :)

Glad to see the experience level finally addressed, but I still don't think it's really sinking how much seat time it REALLY takes to get close to maxing out the performance of just a Miata on the BGK and Rcomps and decent brakes. Not a few days here and there it will take a few dozen track days with instruction to get close anyway. Remember a lot of these guys have been doing HPDE/Racing for far more than a decade, and decades in some cases with regular track time.

Put some decent pads/fluid/ducts on the car, do the BGK if he wants, 15x8 and some 205 200TW or Rcomps, get all your safety stuff sorted out, and then spend as much time behind the wheel as you can for the next 2 years without doing anything else to the car.

And when he thinks he is getting "All of it" out of the car, have him do yet another ride along with one of the experienced local instructors.

I got luck that this was my instructor for a weekend once, it was humbling to see what she was going on the brakes and with slip angles in the corners. Official Website of Kristin Treager Racing

You are preaching to the choir.
I'm just a father trying to keep the racing off the streets and keep the horsepower bug in line.
I am under no illusion as to mastery of the process, I just want him to enjoy it.

The brakes (completely rebuild/ good pads/fluid) seem good for stock power.
When he wants more power he knows he needs more brake.
Maxxis will do him well enough and will keep the consumables down a bit....and the 245s give him the look he wants...
Safety stuff is done
Thanks for your thoughts!

Jamie

if your son is new to track driving, just get him on track in something slow, safe and reliable. the more capable the car, the harder it is to teach the limits without consequence. I think brake fade, and over heated tires are good for a new driver. they need to learn how to drive overheated tires and when to hot brakes are just annoying and when they become dangerous. does he post here? all should read this