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@refirendum

It was one of the first mods I did and don't remember. My focus at that time while the kswap was in process was to properly convert the rack by removing the piston. I didn't even focus on suspension geometry until later once I worked all the kswap wiring bugs out.

@tony_r

The Penske 3W is 13.7cst @40°C. I was figuring below 20cst would be good because the car weighs <1950 with <900 over the front axle.

Most shocks seem to be valved for 3000-3500lb cars.
Off the shelf with the sawdust oil they are OK in the low speed, but lack a real knee point and are basically linear. High speed is awful. With the Penske oil you get a little bit of a knee at 1-2ips but still the same crazy high speed, it's just lower force so most track stuff is totally fine. Tbh it's great at BRP and SoW.
 

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Take apart the BCs and install bilstein pistons and shims.

It works well. I have done it a couple of times.
 

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Plan is to have Feal valve to my specs after dynoing. Having built several winning race cars and having knowledge of suspension and shock tuning, I have a good idea where to go with these.

I think biggest difference I forgot to mention is, when they built these doubles for me, they gave me "custom" valving. Low speed is terrible, high speed ok but with typical excessive comp and underdamped rebound.

Not a Penske or JRi, but they can be great with reshim and oil. That and the quality of construction for being so cheap is why I I'm playing with them.
 

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Their linear pistons suck. They work great with the right piston and shims.

I have a shock dyno so I have been able to dyno many different shocks for the spyder.

I was also able to have a Chinese company just build me a double adjustable twin tube based on my numbers. Unfortunately their adjusters suck as expected. They were able to valve based on my numbers which works very well.
 

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@refirendum

They are the 12mm for S13. 14mm is for S14. Here is the thread I referenced for dims. I modeled the parts from the dims listed (normally I prefer to buy the parts and model parts from actual dimensions) to determine whether the taper was a match:


I believe I bought the Super Now ones from RHDJapan. Their receipts aren't helpful searching back through records. Everything is labeled on the invoices "vehicle strut bar iron or steel".
 

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There are also Miata forum threads detailing differences between Miata, S13, and RX7 outer tie rods. I believe I went S13 because of the length of the arm. Been awhile since that mod.
 

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@refirendum

They are the 12mm for S13. 14mm is for S14. Here is the thread I referenced for dims. I modeled the parts from the dims listed (normally I prefer to buy the parts and model parts from actual dimensions) to determine whether the taper was a match:


I believe I bought the Super Now ones from RHDJapan. Their receipts aren't helpful searching back through records. Everything is labeled on the invoices "vehicle strut bar iron or steel".
Still processing a bit.

When you compared the tapers, was the s13 taper a match or did you have to modify the outer tie rod you got? I'm thinking of getting some adjustable GKTech s13 outers. would that work well for bump steer correction?
 

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@refirendum

They were unmodified. It's been awhile, but the tapers were a match to where I didn't need to modify them. I have a couple thousand miles on them without issue. Sketching the geometry and doing the trig is simple and worth double checking. The biggest issue was the length of the heim joint.

I have never looked at the GKTech S13 outers. That kit looks pretty adjustable.
 

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@refirendum

They were unmodified. It's been awhile, but the tapers were a match to where I didn't need to modify them. I have a couple thousand miles on them without issue. Sketching the geometry and doing the trig is simple and worth double checking. The biggest issue was the length of the heim joint.

I have never looked at the GKTech S13 outers. That kit looks pretty adjustable.
That's great news. i did do the trig for the angles earlier this year, but held off because i wasn't 100% on the idea till now.
what was the issue with the heim joint length?

also, been searching for a solution for a wider front track to run with the Battle version front arms. do you happen to know if the Battle versions also correct for Roll Center at all?
 

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RC correction is dependent on your ride height and LCA angle. This changes the amount of (minimal relative to double a-arm) dynamic camber gain. But, more importantly, it affects the distance between you RC and CG. This distance acts as a moment arm and (put very simply) affects whether you need 1k or 15k springs to keep the car level. The only way they could have a different effect on RC is with extended lower bj's.

What is your reasoning for widening the front track? Depending on your plans with the car, that may not create the effect you are hoping for. Tho, that combined with the GKTech S13 outers seems to point to dorifto.

Wheel rate is the total rate from the springs and sways. A lot more to it like quali/autox big spring small sway vs road race big sway small spring.

RM and RR are tuned like FF - with rear wheel rate - because of the amount of rear grip. You don't want to slap big spring big sway up front. It's not a Camaro, Vette, Viper, etc FR.
 

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That's great news. i did do the trig for the angles earlier this year, but held off because i wasn't 100% on the idea till now.
what was the issue with the heim joint length?

also, been searching for a solution for a wider front track to run with the Battle version front arms. do you happen to know if the Battle versions also correct for Roll Center at all?
The BV arms do not do any RCA, they are set to OE height from what Alex told me. I wouldn't want to do RCA with this design anyway, too much stress on the bolt without double shear.

I worked with Alex to get some beefier tie-rods into the Spyder using SC430 inners and his outer parts from other cars. Having seen some inner failures with big grip and OE rods I didn't want to leave it as-is. It is possible to mix and match items, like the S13 bumpsteer outers with Battle Version rods. If you want that stuff just email and Alex can help.
 
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