Confused about combing parts for best bump steer with a lowered miata - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

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Old 02-06-2015, 05:41 PM   #21
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I understand how ackermann works, I was just trying to say the perceived benefits work on the same principle as ackermann. Toe out in a corner to help the car turn in.
Ackerman creates toe out on the inside wheel. This is creating toe out on the outside wheel, which will have the opposite effect. As Bob says above, softening the turn-in rather than increasing it.
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Old 02-06-2015, 05:43 PM   #22
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Ackerman creates toe out on the inside wheel. This is creating toe out on the outside wheel, which will have the opposite effect. As Bob says above, softening the turn-in rather than increasing it.
during turn in you care more about the toe effects on the inside wheel than the outside. And bump steer isnt in effect during turn in because the car hasnt begun rolling yet.
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Old 02-06-2015, 05:45 PM   #23
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Originally Posted by Mobius View Post
Ackerman creates toe out on the inside wheel. This is creating toe out on the outside wheel, which will have the opposite effect. As Bob says above, softening the turn-in rather than increasing it.
ah yes, that makes sense. i wonder if bob is unknowingly adding more steering angle to compensate.
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Old 02-06-2015, 07:24 PM   #24
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ah yes, that makes sense. i wonder if bob is unknowingly adding more steering angle to compensate.
I think it takes more effort on the steering wheel turning the way I have it now but it is very stable.
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Old 02-07-2015, 03:19 AM   #25
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I will say with the knuckles off it’s pretty hard to come up with 7.1mm higher for the NB looks more like 3mm but it also looks like the way the upper and lower ball joint holes are possibly machined differently I might need more sophisticated measuring tools to determine relative to the actual centers of the ball ends.

Don’t have it together to measure yet but NB subframe with NA knuckles and LE tie rod ends goes from 1.25” total toe in at full rebound to 0.75” total toe out at full bump!! Measured with FM hub stands. Kind of shocked me how much it was.
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Old 02-08-2015, 06:47 PM   #26
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I know for a fact that the upper ball joint on the NB uprights are not drilled as deep which effectively raises the ball joint pivot point. Maybe the lower is drilled deeper as well, the lower is what we care about for bump steer.
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Old 02-08-2015, 08:47 PM   #27
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I measure a huge difference in bump steer with all NB parts.

With all NB Subframe NB knuckles, and LE tie rod ends I only get about 1/16” tow out from ride height to full bump. And 7/8” of total tow in at full shock extension. Meaning very little bump steer from around nominal ride height to full bump for lowered suspension setup and what little bump steer there is is in the right direction for stability.

I suspect NB with standard tie rod ends might tow in a bit at full bump and running the le tie rod ends is a little better for the suspension kinematics in bump if your running lowered and operating at lower ride heights. At stock ride heights standard tie rod ends would be better I think. I don’t think it is worth shimming the NB rack if you run the LE tie rod ends. NA knuckles on an NB subframe produces way too much bump steer correction and screws things up.
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Old 02-11-2015, 03:21 PM   #28
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So consensus is NB everything with LE rod ends?
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Old 02-11-2015, 05:00 PM   #29
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So consensus is NB everything with LE rod ends?
I think that is best based on my measurments. I did not go and look what happens to bump steer while turning however. It's never going to be zero bump steer.
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Old 02-11-2015, 05:19 PM   #30
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Originally Posted by greddygalant View Post
So consensus is NB everything with LE rod ends?
Just to be clear here.

NB front subframe
NB hubs
NA (LE / R-package) tie rods

That is, currently, the best combination to maintain minimal bumpsteer, correct?
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Old 02-11-2015, 05:27 PM   #31
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Originally Posted by bbundy View Post
I think that is best based on my measurments. I did not go and look what happens to bump steer while turning however. It's never going to be zero bump steer.
I've been wondering about that combo for some time but have been too lazy to order some LE rod ends and measure.
Now I don't have to wonder, just procrastinate as I have with the Mini dynapro kit for close to 10 years.

Haven't this combo been used on Spec Pinata since they allowed NB-subframes on all (just wondering)?
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Old 02-11-2015, 06:12 PM   #32
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Originally Posted by 90civichhb View Post
Just to be clear here.

NB front subframe
NB hubs
NA (LE / R-package) tie rods

That is, currently, the best combination to maintain minimal bumpsteer, correct?
Nb subframe
Nb knuckles
LE or NA- R-package tie rod ends.

Based on my measurments I think this is a good setup if you oporate on a lowered suspension that frequently uses all the bump travel as most of the fastest track cars have their setup. I think trying to correct it even more than LE tie rod ends do is too much.
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Old 02-11-2015, 06:14 PM   #33
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Originally Posted by NiklasFalk View Post
I've been wondering about that combo for some time but have been too lazy to order some LE rod ends and measure.
Now I don't have to wonder, just procrastinate as I have with the Mini dynapro kit for close to 10 years.

Haven't this combo been used on Spec Pinata since they allowed NB-subframes on all (just wondering)?
I didn't know they allowed NB subframes on NA's in spec Pinata.
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Old 02-11-2015, 06:26 PM   #34
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Have we determined if there is an aftermarket PN for the LE/R tie rod end? I've got the Mazda PN, I just wonder if anyone else is making them.
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Old 02-11-2015, 06:31 PM   #35
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Have we determined if there is an aftermarket PN for the LE/R tie rod end? I've got the Mazda PN, I just wonder if anyone else is making them.
I know for a fact they sell them aftermarket as well because I bought some.

Let me dig for a receipt to find the manufacturer and I'll edit once I'm home from work.
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Old 02-11-2015, 08:06 PM   #36
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Originally Posted by EO2K View Post
Have we determined if there is an aftermarket PN for the LE/R tie rod end? I've got the Mazda PN, I just wonder if anyone else is making them.
LE R-Package are dealer only. Some places will sell you normal ones even if you specify an LE or R-Package, their computers dont realize the difference.
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Old 02-12-2015, 12:48 AM   #37
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I bought THESE labeled as aftermarket LE tie rod ends. I ended up having to return them because of clearance issues with 949s 11.75" BBK on NA spindles. I had the same problem as Dcamp2 on this board.

I haven't measured them to confirm they are in fact LE/R package copies, just confirmed they wouldn't work for my application

Note that on Parts Geek and CARid, these are listed as specifically compatible with 1993 and 1994 Bilstein equipped cars.

First equipment quality PN# 8535-01118326
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Old 02-12-2015, 01:54 AM   #38
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Just buy oem ones from mazda, easiest way to ensure the right part.
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Old 02-12-2015, 02:10 PM   #39
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Originally Posted by OneTwo View Post
I bought THESE labeled as aftermarket LE tie rod ends. I ended up having to return them because of clearance issues with 949s 11.75" BBK on NA spindles. I had the same problem as Dcamp2 on this board.

I haven't measured them to confirm they are in fact LE/R package copies, just confirmed they wouldn't work for my application

Note that on Parts Geek and CARid, these are listed as specifically compatible with 1993 and 1994 Bilstein equipped cars.

First equipment quality PN# 8535-01118326
I have the Mini Cooper Dynapro Radial caliper 11.75" kit. Right at 1mm clearance between the OE LE tie rod ends and the rotor. Been like that for almost 9 years now and never been an issue.
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Old 02-12-2015, 02:13 PM   #40
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Quote:
Originally Posted by greddygalant View Post
Just buy oem ones from mazda, easiest way to ensure the right part.
That's not a bad plan.

Quote:
Originally Posted by bbundy View Post
I have the Mini Cooper Dynapro Radial caliper 11.75" kit. Right at 1mm clearance between the OE LE tie rod ends and the rotor. Been like that for almost 9 years now and never been an issue.
Correct me if I'm wrong, but thats something very custom you built, correct?
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