MR2sday! Getting ready to race!

"Nonster" (noahnic) 03/08/2016 at 11:30 • Filed to: None

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I’m planning on a full season of autocross, a few track days, and maybe even some rallycross events this year so there’s plenty to do to get the old girl ready! I also sold my RPF1's so I’m shopping for new wheels and tires too!

New Shocks!

The first order of business was to finally install the Koni Yellows. I’ve been running the stock (possibly original) shocks and they are horrible. They were worn out and provided little to no damping so the car flopped around with horrendous body roll when driven hard. The result was a car that was very unstable, especially in the slaloms.

It ended up being a lot easier than I thought it would be to install since you have to replace the strut insert rather than the whole strut. A few special tools would have made the process a little faster or easier, but it can be done with basic hand tools.

They’re adjustable, but only for rebound. Suspension options are pretty limited for Mk1 MR2's, but the Koni’s are regarded as the benchmark for these cars. I’m still using Eibach pro-kit springs and stock sway bars.

With a lazy start on Saturday morning, I still had it done by lunch time. I initially set the shocks to full soft and will play with the adjustment later. After lunch and a quick checkout drive around the block I headed across the river to some of my favorite twisty roads in the wilds of Kentucky.

JESUS TAPDANCING CHRIST!

The MR2 has been transformed. I’m now royally pissed that I waited this long to install these. The car feels so sure-footed and planted now. Even on the 185 width all seasons the car was a joy to hustle up and down the winding roads.

Before when I would go through a hairpin turn (on the road or at autocross) the car would have terrible understeer through the corner with plenty of inside wheelspin at the exit and at high speed turns and slaloms the tail would constantly threaten to beat me to the next apex. I don’t mean to say the car was impossible or dangerous to drive, just that it was only enjoyable to drive at 6 or 7/10's. It just didn’t behave well when pushed hard.

I’ve only driven the new shocks on the street so I haven’t gotten to really push the car hard yet with the new shocks, but on a similar hairpin I was greeted with great turn-in with the car remaining planted through the apex and a nice and tidy slide with just a smidge of oppo as the 20 valve came into its powerband.

As a mechanical engineer and general racing/motorsport fan I know the importance of good shock valving, but its so much fun to feel though the butt-dyno what kind of difference it can make.

The Hunt for Wheels & Tires

My previous set was 15x7 Enkei RPF1's with 205/50R15 Dunlop Star Specs. The tires were old and worn out and I really liked the RPF1's, but I decided that I want to move up to 225 width tires on 8 inch wide wheels. So now I have a decision to make.

I’m woefully underprepped for my AutoX class so I don’t really have much hope for being competitive since the 20 valve swap puts me in SSM with turbo’d Elise’s, Corvette Z06's, RX-7's, etc. So my focus is simply on improving the nut behind the wheel. That said, I’m also using this season to determine if the car and myself has the potential to catch up to the fast guys with a serious set of upgrades or if it would be better to switch to a more competitive car.

With that in mind I’m looking at two different wheel & tire setups

Option 1: 15x8 wheels with 225/45-15 UHP summer tires

Option 2: 13x8 wheels with 225/45-13 Slicks or semi-slicks

I bought one of the 13x8's to check to see if it clears the brakes and suspension components.

It fits! and looks damn good!

Option 1 is simply an upgrade/upsize to what I used to have. This is a good all-rounder DD, track day, and autoX. The wider tires with the shocks will help to close the gap at autox but only minimally.

If I really want to try to close the gap then Option 2 is the more autox focused setup. The smaller diameter reduces weight, inertia, and gives me more favorable gearing for the high revvy 20valve. The wheels are cheap, but the R-compound tires are pricey and they won’t last as long. I’m considering both the Hoosier A7 and Toyo R888. Sadly the nice and cheap Hankook slicks are discontinued.

So what do you guys think? Get R-comps and give it hell or admit defeat?

Local Miata Bro > Nonster 03/08/2016 at 11:44

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Which Kentucky region do you run with? I’m with the KYSCCA and TNSCCA when they come to Bowling Green.

The Crazy Kanuck; RIP Oppositelock > Nonster 03/08/2016 at 11:48

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I would vote the 13" wheels. The tires would be part of the suspension, and I think it handle lots better.

yitznewton > Nonster 03/08/2016 at 11:48

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Awesome!! Red Mk1 is best MR2.

Regarding the chassis, do you have the OEM rear sway bar? The European AW11 dude here has said that they cancelled it in the US market after 1986?, and that it makes the steering dynamics much smoother.

yitznewton > Nonster 03/08/2016 at 11:50

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I’m hoping to dabble in autox for the first time this year, my goal is two sessions on the season. For myself I would not want overly sticky tires while I’m learning the ropes; let the car teach me on nice street rubber first. But that’s my novice impression of a good idea.

nerd_racing > Nonster 03/08/2016 at 11:53

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That’s it, I’m going to have to change the shocks and add a rear swaybar now...

uofime-2 > Nonster 03/08/2016 at 12:03

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R-comps, you will feel like a driving god.

MR2_FTW - Group J's resident Stig > Nonster 03/08/2016 at 12:09

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Good job on the Koni’s. I’ve run most suspension setups available on these cars and they are pretty great. (blown stock, tokico blues + ST springs, tokico blues + JDM TRD springs, koni yellows + JDM TRD springs, koni yellows + GC coilovers) The biggest issue though is front shock travel. when the car is on the ground, shine a flashlight up in there and see how shockingly little travel there is, especially if you lower it at all. Soon I’ll be hacking up some SW20 MR2 front housings and see if I can frankenstein them to work, which will add around 1.5" of shock travel. Only thing is modification of the sway bar end link attachment would be required, so that could be a bit tricky.

MR2_FTW - Group J's resident Stig > yitznewton 03/08/2016 at 12:10

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In the US, 1985 cars had rear sways, but after that they did not, even though the rear struts still have tabs on them through 86. However, some 1989 Supercharged models did have rear sways, but not 1988 SC cars. It’s weird.

Will with a W8 races an E30 > Nonster 03/08/2016 at 12:11

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205/50-15 ZII* is much happier on a 15x8 than a 15x7. There aren’t a whole lot of interesting tires in 225/45-15 (at least not over 180 treadwear), and that size tire seems to work best with a 15x9 anyway. From personal experience, a 205/50R15 ZII* on 15x8 is much faster than the same tire on 15x7, and marginally quicker than a BFG Rival 225/45R15 on 15x8. The stretch makes breakaway more progressive, the tire a bit more responsive, and reduces the tire’s tendency to roll over onto the sidewall under high lateral load.

If you really wanna go fast on a 15, Hoosier Formula Atlantic front tires are 9.5" wide tread on 15" diameter, and are built for a 10"-10.5" wide wheel. Stretch them a bit (~10.5" wide wheel is about right) and they’ll be nice and progressive when they let go while making stupid grip.

And if you’re feeling stupid, FA rears are 13.75" wide. They used to run built 4A-GEs after all....

SidewaysOnDirt still misses Bowie > Nonster 03/08/2016 at 12:20

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R Comps! I’m probably going to be picking up a set of custom rims from Diamond with huge backspacing and bump up to 9 or 10s.

SidewaysOnDirt still misses Bowie > MR2_FTW - Group J's resident Stig 03/08/2016 at 12:22

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Yeah, it’s annoying because it needs it. I just drilled a hole in my spring perch and made a mounting point there. The car’s light enough that I’m not worried about it.

SidewaysOnDirt still misses Bowie > MR2_FTW - Group J's resident Stig 03/08/2016 at 12:23

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Yay, bumpsteer!

SidewaysOnDirt still misses Bowie > nerd_racing 03/08/2016 at 12:23

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Sway bar transforms the car in such a great way. All of that push at the limit before the snap goes away.

Will with a W8 races an E30 > Will with a W8 races an E30 03/08/2016 at 12:25

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Also, if you go the FA route, Maxxis is releasing an RC1 in 245/40R15. It’s designed for a 15x10, so it will work with the same wheels, and it’s a hell of a lot cheaper than Hoosiers.

Nonster > yitznewton 03/08/2016 at 12:55

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yep mines an 85 so it has the oem rear sway bar. Its not huge, probably 1/2" in diameter, but I’m glad I have it

Nonster > MR2_FTW - Group J's resident Stig 03/08/2016 at 13:03

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The lack of travel and bumpsteer and geometry issues is why I haven’t been super quick to jump to coilovers or lowering beyond the eibachs. I’ve been reading that thread on the budget race coilover setup on the forums too.

what spring rates are you running on the GC’s?

Jazzy > Nonster 03/08/2016 at 13:07

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I must ask. Which are your favorite twisty roads in the good ole Commonwealth? I haven’t done too much exploring unfortunately to stretch the Mazdaspeed’s legs. But with Spring returning to the area (for now), I need to get out and drive.

Nonster > SidewaysOnDirt still misses Bowie 03/08/2016 at 13:09

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Hoosier also has the A7 in 255/40-13 maybe I should jump up to 9 or 10 too...but damn A7's are pricey.

Btw that 13x8 in the pics has 5" backspacing and clears everything just fine

nerd_racing > SidewaysOnDirt still misses Bowie 03/08/2016 at 13:10

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Interesting. I hate the push so much. Should I go factory or get a pair of swaybars?

Nonster > Will with a W8 races an E30 03/08/2016 at 13:15

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Really? on an 8" wide wheel the 205 is quicker than the 225? I know the 225 is quicker on a 9" wheel, but I don’t think I can fit that under my front fenders without flares. hmmm interesting tip on the FA tires. I’ll have to look into that.

Nonster > nerd_racing 03/08/2016 at 13:20

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I haven’t gotten a set yet, but I’d go with the ST bars. Even with the factory bars front and rear I still get more body roll than I’d like

Nonster > Jazzy 03/08/2016 at 13:22

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I’m in Cincinnati so I like to down Route 8 out of Covington/Newport. It follows the Ohio river so its pretty fun and theres usually a lot of little side roads that pretty fun.

Nonster > Local Miata Bro 03/08/2016 at 13:24

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I’m actually in Cincinnati so I run with Cincy SCCA and WORSCCA. I want to go to a track day at the National Corvette museum though

Jazzy > Nonster 03/08/2016 at 13:27

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Okay. That’s what I was thinking. I grew up and still live in NKY. I haven’t done the full route 8 drive yet. One of the better drives I’ve done so far is doing US 42 all the way down to Carrollton. I just wanted to get your take! Thanks man

Will with a W8 races an E30 > Nonster 03/08/2016 at 13:33

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That was my experience. At very high lateral loads, the standard recommended rim is usually too narrow, and the tire tends to just let go when you pass the limit instead of progressively falling off. You may be able to get more ultimate grip with enough camber on the wider tire, but the narrower tire on the same rim will usually be a quicker all around package, and easier to drive at the limit.

Nonster > Jazzy 03/08/2016 at 13:45

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Last summer I took a motorcycle trip to Nashville and took 42 all the way to Louisville and its a great route. Especially when you stop for lunch in Warsaw on the river

E92M3 > Nonster 03/08/2016 at 13:49

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Honestly I would get a car that will be competitive. You could keep throwing money at the MR2, and go a couple of times to compete with yourself, but eventually you’ll want to compete with the others.

SidewaysOnDirt still misses Bowie > nerd_racing 03/08/2016 at 14:08

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I only added an ST one to the rear. Front’s still stock.

Scary__goongala! > Nonster 03/08/2016 at 14:10

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I really wanted to buy a MR2 instead of a miata. But I couldn’t find any non-turbo models in my price range that had been well taken care of. Also it seemed like an even less practical car than the NA and I had to draw the line somewhere.

Nonster > E92M3 03/08/2016 at 14:25

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Thats something that I’m seriously considering after this season. After last season I’m definitely getting the itch to be more competitive. AW11's can be competitive in DP but then its a full prep car that needs to be trailered which I don’t want to do just yet.

Or I could go through the trouble of putting a stock motor back in it and run in STS, but taking away horsepower isn’t fun.

MR2_FTW - Group J's resident Stig > Nonster 03/08/2016 at 15:32

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The problem with every lowering spring available for these cars is that it lowers the car without enough stiffness. When I had my JDM TRD springs, it lowered the front a ton but I was constantly bottoming the shocks over bumps.

I’m currently sitting maybe an inch, inch and a half lower than stock with 350lb/in front springs (TRD’s were supposedly around 170ish) and 450lb/in rear (TRD’s were supposedly around 280). Comfort hasn’t suffered at all, but handling is way, way better.

Also note: my car is a supercharged model, so it’s a bit heavier than an NA hardtop model would be.

MR2_FTW - Group J's resident Stig > SidewaysOnDirt still misses Bowie 03/08/2016 at 15:33

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Back in the day TwosRUs used to sell bolt-on collars with tabs on them to retrofit, but they stopped selling them years ago.

MR2_FTW - Group J's resident Stig > SidewaysOnDirt still misses Bowie 03/08/2016 at 15:38

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I’ve never really had bumpsteer issues, that’s more of a geometry issue than a shock travel issue. The guys that run into bumpsteer are usually running BC/Ksport/etc full replacement coilovers that go crazy low.

nerd_racing > SidewaysOnDirt still misses Bowie 03/08/2016 at 15:58

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Interesting. MK1a or MK1b?

Local Miata Bro > Jazzy 03/08/2016 at 19:18

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I’m out by Bowling Green, Ive found some great roads over by Barren River dam if you ever head out that way. KY 255 is my favorite. No traffic, and a speed limit of 55mph helps.

SidewaysOnDirt still misses Bowie > nerd_racing 03/09/2016 at 07:08

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‘89, so 1b. I had to drill holes in the spring perch to make a mounting point.

SidewaysOnDirt still misses Bowie > MR2_FTW - Group J's resident Stig 03/09/2016 at 07:22

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I’ve only ever had it be an issue on rovals where you hit the banking hard, but my car’s also riding a little above stock height even though I eibach springs because I took so much weight off of it. There’s a 5/8 mile oval in my area that runs a ghetto autocross when they have nothing else going on and that’s the only place I’ve ever consistently experienced it.

Jazzy > Local Miata Bro 03/09/2016 at 08:00

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Sweet! May have to hit those up when I take a Mammoth Cave trip later this year!

Local Miata Bro > Jazzy 03/09/2016 at 15:20

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When you do go to Mammoth holler at Oppo’s Bro, and I’ll show you around down there!

nerd_racing > SidewaysOnDirt still misses Bowie 03/10/2016 at 07:08

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do you have a picture of that? Just curious for when my time comes. Almost ready to pull the head off.

SidewaysOnDirt still misses Bowie > nerd_racing 03/10/2016 at 07:28

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No, but there was nothing to it. Literally it was just find a flat spot on the inside of the spring perch away from the spring, drill there, and bolt the mounting clip to that.

nerd_racing > SidewaysOnDirt still misses Bowie 03/10/2016 at 08:20

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perfect, I should be able to handle that.