escapedan

Just sharing as a new user and appreciative member of the forums. Having raced Spec Miata (and other classes) I have recently made the switch from wheel-to-wheel racing to fun, friendly, and less expensive open track events (Northern California).

Suspension wise, I have installed Koni Yellow Adjustible Shocks, Eibach ProKit Springs, 17x8 wheels with Nitto NT-01 255/40/17 tires.

Interesting finding today - I took my car to have the alignment set and requested front camber of -1.5, rear camber of -1.8, zero front toe-in, and very slight rear toe-in. Just received a call from the alignment shop stating the car has -3.3 degrees of rear camber (each side) and -1.8 degrees of front camber. Furthermore, given the width of the tires they cannot reduce the negative camber without causing the tires to rub (car is too low on the shock / spring combo).

Question 1 - Does that much negative camber sound odd to you? (I expected it to have very little negative camber prior to the alignment.)

Question 2 - Does the Koni Yellow / Eibach ProKit combo dramatically lower the car? (I personally feel the car is WAY lower than I expected it to be. I properly tightened the suspension components to avoid binding, etc).

Thanks!

dannobre

iTrader: (3)

What is the offset of the wheels?

archwisp

iTrader: (1)

Yeah, offset and ride height (measure from center cap to bottom of fender) are missing figures here.

I just had my alignment done (details: https://www.rx8club.com/series-i-tec...2/#post4640221) and was able to get up to -1.8 in the front and down to -1.6 in the rear on Yellows and Tein H.Tech springs and I have much wider wheels.

-3 seems per side seems suspiciously high.

escapedan

They are 38mm offset. Specifically, they are Drag DR-38 17X9 5-100/114.38GBR (I incorrectly stated they are 17x8 above - the wheels ARE 17x9).

I will measure ride height tonight. I'm concerned about the negative camber numbers now. I will post pics of the shop printouts tonight.

escapedan

I will also be at Laguna Seca on Thursday and I will be taking complete tire temps and pressures after each run. I will post those as well. Thanks again - I really appreciate being helped out here and hope to give back as much as possible in the years to come. Just getting my feet wet in this great car.

Side note - I have added the BHR Ignition Kit and new plugs as well. Other than that, just flushed radiator, changed transmission and differential fluid, change oil regularly, etc. Chassis has 120k and motor has 22k. All work done at Mazda with service records from prior owner.

escapedan

UPDATE - responses and feedback very welcome!!

The alignment numbers came back as follows:
Front Left Camber = -1.7 Rear Left Camber = -3.4
Front Right Camber = -1.7 Rear Right Camber = -3.4
Front Toe (Total) = 0.01 Rear Toe (Total) = 0.13

I was at Laguna Seca today and my lap times were between 3-4 seconds slower than my last outing (before the alignment) at ~1:50 to 1:51. The tire temps seem to verify the ridiculous amount of rear camber. I averaged the following temps, pressures, times, over 6 sessions at 20 minutes each.

Front Left Outside =150 Front Right Outside = 135
Front Left Center = 145 Front Right Center = 135
Front Left Inside = 150 Front Right Inside = 140

Rear Left Outside = 140 Rear Right Outside = 150
Rear Left Center = 155 Rear Right Center = 160
Rear Left Inside = 165 Rear Right Inside = 165

Hot PSI = 38psi all around
Suspension was set relatively soft
Oustise Temp was ~73 degrees (not sure what track temp was)

escapedan

One More Update - RIDE HEIGHT

Measured from center cap (middle of rim) to bottom of fender:
FRONT = 13 1/4 inches (with 1 in gap between top of tire and bottom of fender)
REAR = 12 inches (no gap exists at all)

dannobre

iTrader: (3)

Do you have the springs in the correct location?

archwisp

iTrader: (1)

That is REALLY low.

When the rear of my car was at about 14" on worn out springs, my 18x9.5 with a 245/40 on it fit. When I went up to a 275/35 on that wheel, the car could not be moved much without the tire rubbing.

With my newly installed H.Tech springs, the car sits at 13.75" and that 275 fits just fine. I expect this top drop a bit over time.

From reading the race forums, it seems like 13.5" is a common ride height with lowering springs.

At 12" with RB springs and yellows, I would say your suspension components are suspect.

Good luck,
Bryan

escapedan

I'm actually glad to hear this - I too think something is up. Good point on the spring location, they do look very similar and don't have a clear "FR / RR" marking on them (not normally the case on other cars I've built). I'm going to take a look at the springs tonight, but I called I called Eibach a few moments ago and they gave me the following.

Front Spring Part Number = 11-55-007-01-VA
Rear Spring Part Number = 11-55-007-01-HA

escapedan

I do have the springs on the correct ends. No question there. I went through and loosened all the suspension bolts and re-tightened ensuring there is no binding. I also rotated the bottom of the rear shocks 1/2 turn. The "end" of the spring is now facing outward, but I'm not sure there is any difference.

That said, I did get some improvement on the ride height - my guess is I didn't do as good a job with the initial installation as I thought and maybe the rear was in fact binding in a compressed position.

CURRENT Measured from center cap (middle of rim) to bottom of fender:
FRONT = 14.0 inches (was 13 1/4 inches)
REAR = 13.5 inches (was 12 inches)

archwisp

iTrader: (1)

Those ride heights seem much more reasonable but the fronts still seem a bit high given that most lowering springs give you pretty even ride height. You mentioned losening the bolts but did you leave the two upper control arm bolts and the shock bolt loose until after the car was lowered?

And yeah, if you had the spring perches facing inward, you had your dampers installed backwards. On mine, the Koni sticker is on the innner side (not visible from the wheel).

Sounds like you're making progress!

escapedan

Thank you, Archwisp. Much appreciated. I did not leave the front suspension bolts loose before lowering the car but I will go back tighten them with the car sitting on the ground / ramps this morning and see if that drops a bit. I will drive around as well to see how the settling further drops it. Agreed, progress is being made!

I took a real good look at the suspension components last night - they definitely look like a chassis with 120k on it. The roll bar end link bushings are completely shot and most of the bushings really do need to be replaced. The suspension arms look very good with no visible damage of any kind. Wheel bearings are in good shape. It handled surprisingly well at the track given the miles on the chassis.

Do you suggest going with OEM bushings all around or switching to an aftermarket product? I am hesitant to use poly because I would like to retain some "cushion" on the street and my experience with poly has been pretty extreme.

I am very excited to continue the improvements!

Loki

iTrader: (1)

In many cases, like the rear lower arms, you can't buy an OEM bushing separately, you have to buy the whole link. It's actually a problem on older RX8s: the camber/caster setting bolts seize and you have to scrap the entire link. I personally haven't tried poly in those locations, for the same reasons

I bet that with the rear suspension at uncompressed height, your camber is also back to some semblance of normal

Arca_ex

iTrader: (10)

Lowering the car increases static camber so the numbers for the rear sound right for how low the car is.

I run about -2.8 camber in the front and -3.0 in the rear but I also don't own a pyrometer. That's just going off of tire wear and how it feels on track. Also zero toe all around. Your temp readings definitely show that less negative camber out back would help. I would maybe try for at least -2.0 in the front or else outside edge wear on the tires might be an issue.

Like Loki said, you can't buy just the bushings from Mazda for the rear they only sell the complete links. The only options for bushing replacement are poly bushings or spherical bearings. The front control arms you can still buy stock replacements for though. I prefer poly or delrin but your definition of streetable is probably much different than mine.

escapedan

Quick update here - I fully expect to take grief for this post and I do realize this is not a recommended fix, but it solved my issue as a quick fix in the interim. Note, I am on work assignment out of state so I get very little time to work on and play with car during my trips home...

I checked all the spring and shock settings multiple times, ensure there was no binding, etc. to no avail. The rear of the car just sits crazy low. Even relative to other user photos with the same springs.

So, before I go and purchase coilovers (which I should have just done to begin with) I added a Mr. Gasket 1285 Front Coil Spring Booster (1 inch) to each of the rear shocks (took some modification and added to the top of the spring). The result, the car rides about 1" higher in the rear. Shocking, I know. More shocking is my willingness to admit this monstrosity of workmanship...

I made no other changes to the suspension or alignment and took it back to Mazda Laguna Seca on 12/28. Decent weather conditions and dry track. Lap times were about 2 seconds faster than my last post and the car handled much better. There was no sense of bottoming out in Turn 6, Turn 10, or at the bottom of the corkscrew. Tire temps were consistent across at the same hot PSI.

Anyway, Happy New Year!!! Zoom Zoom.