Does the Z have a rear toe-steer problem?

kenchan · 01-26-2012, 03:50 PM

Quote:

Originally Posted by Red__Zed

I am choosing my words carefully here to avoid having them misconstrued by some of the overly sensitive members here, so the answer I will give is I believe so

lame!!

Guard Dad · 01-26-2012, 04:51 PM

Quote:

Originally Posted by Red__Zed

I am choosing my words carefully here to avoid having them misconstrued by some of the overly sensitive members here, so the answer I will give is I believe so

I would agree with both of these. I also agree that the first is likely not practical.
I have no real experiece with the Megan arms, but I am always hesitant to use Megan parts. I know that a longer arm is needed to get good bump dynamic, but at the same time, I don't imagine you have the time/money to play around with a bunch of different parts.

If you do get the Megan arms, definitely post up thoughts though. I'd be curious to see if it sorts out the craziness (and it would be pretty helpful for anyone else that experiences it)

Your caution is appreciated.

If can make this better I'd be happy to share anything that I learn.

Do you have any idea if the rear suspension has much range of adjustment, any feel if it could tolerate a somewhat longer (1", just a guess) torque arm without wholesale component replacement to allow proper alignment?

Something I should know about Megan?

dAvenue · 01-26-2012, 04:20 PM

Lmao

Red__Zed · 01-26-2012, 04:57 PM

I haven't spent enough time considering the swap to know what you can get away with, and I obviously don't have access to a z anymore, so you'll have to rely on someone else.

Megan is largely a knock off brand. Some of their products are fine, others are spotty. I try to avoid spotty suspension pieces.

kenchan · 01-26-2012, 05:32 PM

Megan is a Taiwanese brand(?) They got the name from Mugen.

The above was posted with caution .

ChrisSlicks · 01-26-2012, 06:09 PM

The SPL parts look much more durable to me and I believe are lighter due to use of better materials.

SPL PRO SUSPENSION | 09+ Nissan 370Z Z34

Skeeterbop · 01-26-2012, 06:53 PM

This is pretty interesting. I had a 91 MR-2 turbo and it definitely had a bit of bump steer. I think this is more a case of the back end just getting a bit light though. Also the difference that Red_Zed got from ride height to full compression was only 1/32 not 1/16. So I do agree that there is some bump steer going on but it is barely an issue IMO at least in compression. What I would love to know is how much it changes in droop. My thought is that while it may not change much under compression, how much does it change when it is in droop after going over the bump and before it comes down and settles. I'll be getting a new set of tires in the next couple weeks and plan on getting the alignment redone. I'll try to see if they can find a way to get the suspension to a bit and see how it affects the suspension geometry.

Red__Zed · 01-26-2012, 07:22 PM

Quote:

Originally Posted by Skeeterbop

This is pretty interesting. I had a 91 MR-2 turbo and it definitely had a bit of bump steer. I think this is more a case of the back end just getting a bit light though. Also the difference that Red_Zed got from ride height to full compression was only 1/32 not 1/16. So I do agree that there is some bump steer going on but it is barely an issue IMO at least in compression. What I would love to know is how much it changes in droop. My thought is that while it may not change much under compression, how much does it change when it is in droop after going over the bump and before it comes down and settles. I'll be getting a new set of tires in the next couple weeks and plan on getting the alignment redone. I'll try to see if they can find a way to get the suspension to a bit and see how it affects the suspension geometry.

No, it changes a lot more from rest to compressed than it does from unloaded to rest. It's not a linear relation.

Skeeterbop · 01-26-2012, 08:13 PM

Red_Zed your measurements were taken from ride height to fully compressed right? So if it has less change from unloaded to rest and the change from rest to fully compressed is pretty minimal (~1/32 difference) would this kill the bump steer idea? I know it's still there on paper, but can the average person feel the difference of 1/32? I've gone over a few sharp bumps in corners at interstate speeds (one freeway interchange ramp really got my attention the first time i hit it) and i just assumed that it is the tires getting a bit light, not bumpsteer. My thinking was that with the bumps I've encounterd the backend hits the bump and as the back end rises a bit the rear wheels get unweighted just a little bit and it causes the lose feeling. I'm not a suspension expert though so I could be a bit or way off. Forgot to mention that i realize it isn't a linear change. But i was thinking that if it gains more toe under compression that under droop it would lose toe. Where are these bump steer gauges that you speak of? I would love to get a set to play with if they aren't too expensive.

Red__Zed · 01-26-2012, 08:24 PM

Quote:

Originally Posted by Skeeterbop

Red_Zed your measurements were taken from ride height to fully compressed right? So if it has less change from unloaded to rest and the change from rest to fully compressed is pretty minimal (~1/32 difference) would this kill the bump steer idea? I know it's still there on paper, but can the average person feel the difference of 1/32? I've gone over a few sharp bumps in corners at interstate speeds (one freeway interchange ramp really got my attention the first time i hit it) and i just assumed that it is the tires getting a bit light, not bumpsteer. My thinking was that with the bumps I've encounterd the backend hits the bump and as the back end rises a bit the rear wheels get unweighted just a little bit and it causes the lose feeling. I'm not a suspension expert though so I could be a bit or way off. Forgot to mention that i realize it isn't a linear change. But i was thinking that if it gains more toe under compression that under droop it would lose toe. Where are these bump steer gauges that you speak of? I would love to get a set to play with if they aren't too expensive.

http://www.amazon.com/Longacre-Bump-.../dp/B000VAPZKO

I don't have my exact numbers in front of me, but I think the car lost less than 1/64 from rest to full up, though I could be off

Guard Dad · 01-26-2012, 08:16 PM

I'm tracking these posts with great interest.

Skeeterbop · 01-26-2012, 11:35 PM

wow, thats expensive if i'm just getting it to play around with. Also that isn't very bad at all imo if it changes from lets say ~3/64 to 6/64 (that would cover the change from full droop to full compression if my math is right), it seems that the toe angle is pretty well controlled.

Red__Zed · 02-02-2012, 01:49 PM

Quote:

Originally Posted by Skeeterbop

wow, thats expensive if i'm just getting it to play around with. Also that isn't very bad at all imo if it changes from lets say ~3/64 to 6/64 (that would cover the change from full droop to full compression if my math is right), it seems that the toe angle is pretty well controlled.

Personally, my ideal would be less than 1/64 of gain for a street/track car. I'd prefer no gain (personally) for a car that spent more time on the track, though it would change depending on the layout. Much of this is preference, but pulling another 3/64s will upset balance when at the limit, especially if you are cpming from expansion out of the braking zone.

dAvenue · 02-04-2012, 04:10 PM

I purchased the Koni's because of this bumpsteer issue. When I initially installed them, I firmed up the rears by +3 (out of 8 max) and left the fronts at +1. Took it out for a test drive that day and I noticed a significant improvement, immediately. However, there was still a little bit of residual symptoms of bumpsteer during the test drive (it got a little wobbly on me).

After reading the subsequent posts in this thread, I thought I would try firming the rears a bit more. I turned them up from +3 to +5 and left the fronts alone. Today, I took it out to the twisties and had an awesome drive. This configuration, for me, eliminated the symptoms that used to scare the hell out of me. I highly recommend considering the Koni's ahead of the adjustable control arms.

m4a1mustang · 02-04-2012, 06:24 PM

Quote:

Originally Posted by dAvenue

I purchased the Koni's because of this bumpsteer issue. When I initially installed them, I firmed up the rears by +3 (out of 8 max) and left the fronts at +1. Took it out for a test drive that day and I noticed a significant improvement, immediately. However, there was still a little bit of residual symptoms of bumpsteer during the test drive (it got a little wobbly on me).

After reading the subsequent posts in this thread, I thought I would try firming the rears a bit more. I turned them up from +3 to +5 and left the fronts alone. Today, I took it out to the twisties and had an awesome drive. This configuration, for me, eliminated the symptoms that used to scare the hell out of me. I highly recommend considering the Koni's ahead of the adjustable control arms.

Good to hear you got her dialed in.

01-26-2012, 04:20 PM	#3 (permalink)
dAvenue A True Z Fanatic Join Date: Aug 2010 Location: present Posts: 1,971 Drives: angry Rep Power: 49	Lmao __________________ Takeda \| Stillen \| Z1 \| Invidia \| Mishimoto \| CSF \| Megan Racing \| Koni \| Eibach \| SPC \| Forgestar \| Seibon

01-26-2012, 06:09 PM	#6 (permalink)
ChrisSlicks A True Z Fanatic Join Date: Mar 2009 Location: North East Posts: 6,203 Drives: 09 370Z Sport M6 Rep Power: 654	The SPL parts look much more durable to me and I believe are lighter due to use of better materials. SPL PRO SUSPENSION \| 09+ Nissan 370Z Z34 __________________ Hotchkis ARB \| Stillen CAI \| Art Pipes \| Berk CBE \| Stillen AP Racing Brakes \| AE Performance Oil Cooler \| BC Racing ER Coilovers \| Doran Control Arms

01-26-2012, 06:53 PM	#7 (permalink)
Skeeterbop A True Z Fanatic Join Date: Jan 2011 Location: Fort Bliss, TX Age: 41 Posts: 1,440 Drives: 2011 GM 370 base SP Rep Power: 17	This is pretty interesting. I had a 91 MR-2 turbo and it definitely had a bit of bump steer. I think this is more a case of the back end just getting a bit light though. Also the difference that Red_Zed got from ride height to full compression was only 1/32 not 1/16. So I do agree that there is some bump steer going on but it is barely an issue IMO at least in compression. What I would love to know is how much it changes in droop. My thought is that while it may not change much under compression, how much does it change when it is in droop after going over the bump and before it comes down and settles. I'll be getting a new set of tires in the next couple weeks and plan on getting the alignment redone. I'll try to see if they can find a way to get the suspension to a bit and see how it affects the suspension geometry. __________________ Srenity: "Yeah no rest needed to spread the love when your 20 that's for sure...."

01-26-2012, 08:13 PM	#9 (permalink)
Skeeterbop A True Z Fanatic Join Date: Jan 2011 Location: Fort Bliss, TX Age: 41 Posts: 1,440 Drives: 2011 GM 370 base SP Rep Power: 17	Red_Zed your measurements were taken from ride height to fully compressed right? So if it has less change from unloaded to rest and the change from rest to fully compressed is pretty minimal (~1/32 difference) would this kill the bump steer idea? I know it's still there on paper, but can the average person feel the difference of 1/32? I've gone over a few sharp bumps in corners at interstate speeds (one freeway interchange ramp really got my attention the first time i hit it) and i just assumed that it is the tires getting a bit light, not bumpsteer. My thinking was that with the bumps I've encounterd the backend hits the bump and as the back end rises a bit the rear wheels get unweighted just a little bit and it causes the lose feeling. I'm not a suspension expert though so I could be a bit or way off. Forgot to mention that i realize it isn't a linear change. But i was thinking that if it gains more toe under compression that under droop it would lose toe. Where are these bump steer gauges that you speak of? I would love to get a set to play with if they aren't too expensive. __________________ Srenity: "Yeah no rest needed to spread the love when your 20 that's for sure...."

01-26-2012, 08:16 PM	#11 (permalink)
Guard Dad Enthusiast Member Join Date: Aug 2010 Location: South Orange County, CA Posts: 422 Drives: 2010 370Z Silver A7 Rep Power: 15	I'm tracking these posts with great interest. __________________ 2010 Brilliant Silver, Base w/Sport Package, AT7, Katzkin leather, upgraded audio and lots of Dynamat and a bunch of small stuff.

01-26-2012, 04:57 PM	#4 (permalink)
Red__Zed A True Z Fanatic Join Date: Jul 2010 Location: window seat Posts: 28,940 Drives: Mostly on two wheels Rep Power: 120	I haven't spent enough time considering the swap to know what you can get away with, and I obviously don't have access to a z anymore, so you'll have to rely on someone else. Megan is largely a knock off brand. Some of their products are fine, others are spotty. I try to avoid spotty suspension pieces.

01-26-2012, 05:32 PM	#5 (permalink)
kenchan A True Z Fanatic Join Date: Aug 2009 Location: N/A Posts: 76,801 Drives: N/A Rep Power: 141521	Megan is a Taiwanese brand(?) They got the name from Mugen. The above was posted with caution .

01-26-2012, 11:35 PM	#12 (permalink)
Skeeterbop A True Z Fanatic Join Date: Jan 2011 Location: Fort Bliss, TX Age: 41 Posts: 1,440 Drives: 2011 GM 370 base SP Rep Power: 17	wow, thats expensive if i'm just getting it to play around with. Also that isn't very bad at all imo if it changes from lets say ~3/64 to 6/64 (that would cover the change from full droop to full compression if my math is right), it seems that the toe angle is pretty well controlled. __________________ Srenity: "Yeah no rest needed to spread the love when your 20 that's for sure...." Last edited by Skeeterbop; 01-26-2012 at 11:35 PM. Reason: spelling

02-04-2012, 04:10 PM	#14 (permalink)
dAvenue A True Z Fanatic Join Date: Aug 2010 Location: present Posts: 1,971 Drives: angry Rep Power: 49	I purchased the Koni's because of this bumpsteer issue. When I initially installed them, I firmed up the rears by +3 (out of 8 max) and left the fronts at +1. Took it out for a test drive that day and I noticed a significant improvement, immediately. However, there was still a little bit of residual symptoms of bumpsteer during the test drive (it got a little wobbly on me). After reading the subsequent posts in this thread, I thought I would try firming the rears a bit more. I turned them up from +3 to +5 and left the fronts alone. Today, I took it out to the twisties and had an awesome drive. This configuration, for me, eliminated the symptoms that used to scare the hell out of me. I highly recommend considering the Koni's ahead of the adjustable control arms. __________________ Takeda \| Stillen \| Z1 \| Invidia \| Mishimoto \| CSF \| Megan Racing \| Koni \| Eibach \| SPC \| Forgestar \| Seibon

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