Truechoice/Unitech coilover review
07-05-2005, 02:09 PM
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Truechoice/Unitech coilover review
Two weeks ago, I made the 7 hour trek from San Francisco to Unitech Racing at Willow Springs International Speedway to take advantage of their offer to install their first few Truechoice phase 4 coilover kits. First off, I want to say thanks to Jackson and crew for being excellent hosts. There is truly no one out there that knows more about the Z. Jackson let me take the white Z used in the coilover comparison test out for a spin to try out the tilton street clutch (and phase 4 coilovers). If my clutch ever dies, I will be getting one of these.
Now on to the install. It was great knowing that my car was in the hands of the crew who works on the grand-am cup 350Z race cars for a living! We have all seen the posts where shops botched up installs.. With the 2 mechanics working on my car, the new shocks and springs were on my car in about an hour. The drop was just over an inch. It looked very low to me at first, but I figured I just wasn’t used to seeing it that way, so we left it as is. After everything was installed, they set up a very nifty lazer alignment rig and aligned everything to their specs. After each adjustment, they brought the car down and rolled it back and forth a few feet (I bet your local alignment shop doesn’t do this). A trip to the scales indicated the car was ok and no corner weight adjustments were needed (3250lbs with half tank of gas and spare removed for those who are interested. Darn 50lb rollbar
).
Now on to the install. It was great knowing that my car was in the hands of the crew who works on the grand-am cup 350Z race cars for a living! We have all seen the posts where shops botched up installs.. With the 2 mechanics working on my car, the new shocks and springs were on my car in about an hour. The drop was just over an inch. It looked very low to me at first, but I figured I just wasn’t used to seeing it that way, so we left it as is. After everything was installed, they set up a very nifty lazer alignment rig and aligned everything to their specs. After each adjustment, they brought the car down and rolled it back and forth a few feet (I bet your local alignment shop doesn’t do this). A trip to the scales indicated the car was ok and no corner weight adjustments were needed (3250lbs with half tank of gas and spare removed for those who are interested. Darn 50lb rollbar
).
07-05-2005, 02:10 PM
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Without further a due, my initial impressions…
I left the shop with bump and rebound set at the recommended 6 out of 10. It was definitely firmer than stock but not punishing, which is a good thing for us enthusiasts.. Cornering was slightly flatter than stock as well as nose dive and squat but not by much. One thing I noticed was that the ride felt a little bouncy to me, kind of like the 03 Z’s (more on this later). My trip home entailed about 6 hours of driving in a straight line until the last leg over Pacheco pass so I would have to patiently wait a few hours to give the new setup a try. I left the shop as happy as could be. I was dreaming of track days without deadly oversteer, when it hit me (literally). The largest bird known to man hit me square in the middle of my windshield. I swear it was a prehistoric pterodactyl of some sort but Jackson told me that there was dead crow in the road about a mile from the shop. My story is that I hit the largest bird known to man and I’m sticking to it.
I digress, after stopping in a Bakersfield for a new windshield, I continued on my way home. It wasn’t until I hit Pacheco pass that I really got a taste for what these were all about. The bounce that I felt initially after leaving the shop translated into a car that hit a bump or transition and immediately bounced back and took a set. No more wobble wobble and uneasiness felt from the stock shocks. The next day I bumped the rear reabound up one click per Jackson’s recommendation and the bounce was totally eliminated! I was amazed at the difference one click made. These aren't coilovers with 30 clicks that do nothing. One click on the konis really changes the attitude of the car. I later found that a dialing down the adjustments to 1 and 2 makes for a comfortable street ride (thanks Jritt).
I left the shop with bump and rebound set at the recommended 6 out of 10. It was definitely firmer than stock but not punishing, which is a good thing for us enthusiasts.. Cornering was slightly flatter than stock as well as nose dive and squat but not by much. One thing I noticed was that the ride felt a little bouncy to me, kind of like the 03 Z’s (more on this later). My trip home entailed about 6 hours of driving in a straight line until the last leg over Pacheco pass so I would have to patiently wait a few hours to give the new setup a try. I left the shop as happy as could be. I was dreaming of track days without deadly oversteer, when it hit me (literally). The largest bird known to man hit me square in the middle of my windshield. I swear it was a prehistoric pterodactyl of some sort but Jackson told me that there was dead crow in the road about a mile from the shop. My story is that I hit the largest bird known to man and I’m sticking to it.
I digress, after stopping in a Bakersfield for a new windshield, I continued on my way home. It wasn’t until I hit Pacheco pass that I really got a taste for what these were all about. The bounce that I felt initially after leaving the shop translated into a car that hit a bump or transition and immediately bounced back and took a set. No more wobble wobble and uneasiness felt from the stock shocks. The next day I bumped the rear reabound up one click per Jackson’s recommendation and the bounce was totally eliminated! I was amazed at the difference one click made. These aren't coilovers with 30 clicks that do nothing. One click on the konis really changes the attitude of the car. I later found that a dialing down the adjustments to 1 and 2 makes for a comfortable street ride (thanks Jritt).
Last edited by daveh; 07-05-2005 at 02:12 PM.
07-05-2005, 02:19 PM
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Enough of the street impressions, I bought these for the track right? I had the chance to drive them at Thunderhill for 2 days. The bottom line is, I was able to knock 4 seconds off my lap times in comparison to the stock shocks/springs and I have no doubt that I can take off another 2 seconds when I get them dialed in. My goal is to get down into the 10’s at this track. The softer spring rates along with the perfect dampening really soak up the bumps! The best way to describe these shocks is that they faster you go, the better they work. At 7/10's these shocks feel just like any other shock on the market. It's not until you really start pushing your car on the track, that you really feel the difference.
For those familiar with thunderhill, turn 8 is an example of how the shocks control the cars motion. Previously, I couldn’t take this turn at more than 85 without the chassis getting upset and feeling uneasy. With the koni’s, I was consistently entering this turn at 95 and the car felt rock solid. I tried it a 100 once and spooked myself, but the car had more in it! All day, I was finding myself running out of revs and having to shift into gears I have never used at the hill. I did experience some corner exit oversteer on turn 1, the 90 degree medium speed corner. I explained as best as I could from Jackson what I was feeling in this corner (and send him a video clip) and he realized that I was running out of rear shock travel. He had me cut the bump stop and raise the car a bit. I will report my findings in early August after my next track day.
Wow, I’ve rambled here but I wanted to capture everything about these since we're talking about people's hard earned money. I have no regrets in this purchase. My opinion is that if you never track your car, these are not for you. On the street, these feel no different than many of the other kits on the market. These really don't come alive until you're at the limit on a closed track! Feel free to ask any questions if there is anything I did not cover.
For those familiar with thunderhill, turn 8 is an example of how the shocks control the cars motion. Previously, I couldn’t take this turn at more than 85 without the chassis getting upset and feeling uneasy. With the koni’s, I was consistently entering this turn at 95 and the car felt rock solid. I tried it a 100 once and spooked myself, but the car had more in it! All day, I was finding myself running out of revs and having to shift into gears I have never used at the hill. I did experience some corner exit oversteer on turn 1, the 90 degree medium speed corner. I explained as best as I could from Jackson what I was feeling in this corner (and send him a video clip) and he realized that I was running out of rear shock travel. He had me cut the bump stop and raise the car a bit. I will report my findings in early August after my next track day.
Wow, I’ve rambled here but I wanted to capture everything about these since we're talking about people's hard earned money. I have no regrets in this purchase. My opinion is that if you never track your car, these are not for you. On the street, these feel no different than many of the other kits on the market. These really don't come alive until you're at the limit on a closed track! Feel free to ask any questions if there is anything I did not cover.
Last edited by daveh; 07-05-2005 at 02:21 PM.
07-05-2005, 05:49 PM
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My opinion is that if you never track your car, these are not for you. On the street, these feel no different than many of the other kits on the market.
07-05-2005, 09:22 PM
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Originally Posted by Gsedan35
500/425
And to Dave, nice write up and thank you for taking the time to type it all up
And to Dave, nice write up and thank you for taking the time to type it all up
can you be more specific on the body roll of the car? is it a lot? nose diving?
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07-06-2005, 12:39 PM
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The spring rates do seem soft in comparison to some of the other offerings but the springs and shocks were derived from their grand-am cars. And they're winning races. What else is there to say..
To answer your question about the body roll, it is slightly less than stock. I never felt that the stock setup had too much roll, it was just uncontrolled, especially on high speed tracks making the car unstable. The car still rolls underneath you but it really allows you to feel what it is doing underneath you. The konis control the motion much better so you never get that uneasy feeling you get with the stock shocks.
I guess it's hard to explain, but I can compare it to my recent students Z with hipermax II's. The HKS are definatly a notch stiffer and when I was in the passenger seat, they felt really good. I was even questioning if my fancy setup was necessary. However when I got behind the wheel of his car that I soon realized that above 8/10'ths they weren't nearly as stable as the koni's. The compliance you get from the softer spring seemed to be a good thing. At the limit, the most minor bumps and surface irregularities were upsetting the chassis with the HKS's. Again you won't see the potential of these until you get to the limits at a track.
On another note, I got the spherical bearing upper mounts . As I expected, they transmit some more road noise and knock a little in parking lots and big bumps. Typical characteristics of monoball mounts.
To answer your question about the body roll, it is slightly less than stock. I never felt that the stock setup had too much roll, it was just uncontrolled, especially on high speed tracks making the car unstable. The car still rolls underneath you but it really allows you to feel what it is doing underneath you. The konis control the motion much better so you never get that uneasy feeling you get with the stock shocks.
I guess it's hard to explain, but I can compare it to my recent students Z with hipermax II's. The HKS are definatly a notch stiffer and when I was in the passenger seat, they felt really good. I was even questioning if my fancy setup was necessary. However when I got behind the wheel of his car that I soon realized that above 8/10'ths they weren't nearly as stable as the koni's. The compliance you get from the softer spring seemed to be a good thing. At the limit, the most minor bumps and surface irregularities were upsetting the chassis with the HKS's. Again you won't see the potential of these until you get to the limits at a track.
On another note, I got the spherical bearing upper mounts . As I expected, they transmit some more road noise and knock a little in parking lots and big bumps. Typical characteristics of monoball mounts.
07-06-2005, 01:59 PM
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thanks for your time to type it out, i'm in the market to change my suspensions(currently have zeal v6). Currently what i have in mind is either JRZ or Motons double adjustable, this Truechoice/koni setup is cheaper, so i'd like to hear more on it.
guess the good thing with this koni setup is the valving is greatly vavled with softer spring. DaveH or anyone have expereince with say this setup and JRZ/Motons double adjustable?
thanks again.
guess the good thing with this koni setup is the valving is greatly vavled with softer spring. DaveH or anyone have expereince with say this setup and JRZ/Motons double adjustable?
thanks again.
07-08-2005, 08:37 PM
#11
Great review. 4 seconds a lap seems worth the money. I'm really wondering about your oversteer. I've got the Tein Basics with 500 lbs springs front and rear with equal sized tires front and rear and hotchkis sways set at medium up front and soft in back and my car goes into a full 4 wheel drift almost perfectly if I overcook entry. The rear is very planted upon exit and I rarely get the back end loose with the exception of slower corners where I do get some throttle oversteer if I'm not careful. (Note: The rear breaks away just an instant earlier than the front, but its almost unnoticable.)
Why do you think you still have oversteer on exit? Also, I was wondering if you could describe your driving style? Are you getting oversteer from throttle or steering input?
Why do you think you still have oversteer on exit? Also, I was wondering if you could describe your driving style? Are you getting oversteer from throttle or steering input?
Last edited by zillinois; 07-08-2005 at 08:46 PM.
07-08-2005, 09:55 PM
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John, first off having compression and rebound settings is a whole new thing for me. It really adds a new dimension to tuning. I think the biggest thing I learned is that it's really easy to mess things up You know it right away when you make an adjustment for the worse.
The first adjustments I was making at the track were to try and tame the exit oversteer in turn 2. I added rebound to the front and took compression out of the rear per Jackson's recommendation (this was before we realized I was hitting the bump stops). This adjustment definately changed the way the car turned in. When I added a second click the car felt more skittish on turn in, settled down nicely at apex and oversteered on exit. Since we didn't realize the problem was rear shock travel, the changes we were making were not helping at all
For my next day at the track, I brought the settings back to baseline for the first session. I decided to add one more click of compression too settle the car more for the high speed dip of turn 8. It made a difference as the car felt more planted in this 95mph mid-corner bump. The best way to describe one click is that you don't really feel the difference in the way goes through the bump and rebound settings but at the limit, the car behaves ever so slightly differently. At 2 clicks, the car more noticeably oscillates differently over bumps.
Zillinois, as I mentioned my oversteer was caused by hitting the rear bump stops. This is why I only had this problem on the one long speed corner. The rest of the track was perfect. Corner entry and apex were very well balanced via even throttle. I would get a nice balanced ride until the rear hit the bump stop then the rear would come around. This is much different than the entry/mid corner oversteer from my stock shocks. Jackson also agreed that the stock setup exhibited these characteristics so I'm not sure why some people say a stock Z oversteers and some say it understeers. Maybe it's an 03 vs 04 thing. I also have the evo camber arms up front which give more more grip up front than stock.
At any rate, I have made my adjustments and gained a little over an inch of rear travel so I think I will be golden next time out. I'll be putting some zip ties on shock to measure the travel as well.
You know it right away when you make an adjustment for the worse. The first adjustments I was making at the track were to try and tame the exit oversteer in turn 2. I added rebound to the front and took compression out of the rear per Jackson's recommendation (this was before we realized I was hitting the bump stops). This adjustment definately changed the way the car turned in. When I added a second click the car felt more skittish on turn in, settled down nicely at apex and oversteered on exit. Since we didn't realize the problem was rear shock travel, the changes we were making were not helping at all
For my next day at the track, I brought the settings back to baseline for the first session. I decided to add one more click of compression too settle the car more for the high speed dip of turn 8. It made a difference as the car felt more planted in this 95mph mid-corner bump. The best way to describe one click is that you don't really feel the difference in the way goes through the bump and rebound settings but at the limit, the car behaves ever so slightly differently. At 2 clicks, the car more noticeably oscillates differently over bumps.
Zillinois, as I mentioned my oversteer was caused by hitting the rear bump stops. This is why I only had this problem on the one long speed corner. The rest of the track was perfect. Corner entry and apex were very well balanced via even throttle. I would get a nice balanced ride until the rear hit the bump stop then the rear would come around. This is much different than the entry/mid corner oversteer from my stock shocks. Jackson also agreed that the stock setup exhibited these characteristics so I'm not sure why some people say a stock Z oversteers and some say it understeers. Maybe it's an 03 vs 04 thing. I also have the evo camber arms up front which give more more grip up front than stock.
At any rate, I have made my adjustments and gained a little over an inch of rear travel so I think I will be golden next time out. I'll be putting some zip ties on shock to measure the travel as well.
Last edited by daveh; 07-08-2005 at 10:04 PM.
07-09-2005, 03:21 AM
#14
Originally Posted by daveh
John, first off having compression and rebound settings is a whole new thing for me. It really adds a new dimension to tuning. I think the biggest thing I learned is that it's really easy to mess things up You know it right away when you make an adjustment for the worse.
The first adjustments I was making at the track were to try and tame the exit oversteer in turn 2. I added rebound to the front and took compression out of the rear per Jackson's recommendation (this was before we realized I was hitting the bump stops). This adjustment definately changed the way the car turned in. When I added a second click the car felt more skittish on turn in, settled down nicely at apex and oversteered on exit. Since we didn't realize the problem was rear shock travel, the changes we were making were not helping at all
For my next day at the track, I brought the settings back to baseline for the first session. I decided to add one more click of compression too settle the car more for the high speed dip of turn 8. It made a difference as the car felt more planted in this 95mph mid-corner bump. The best way to describe one click is that you don't really feel the difference in the way goes through the bump and rebound settings but at the limit, the car behaves ever so slightly differently. At 2 clicks, the car more noticeably oscillates differently over bumps.
Zillinois, as I mentioned my oversteer was caused by hitting the rear bump stops. This is why I only had this problem on the one long speed corner. The rest of the track was perfect. Corner entry and apex were very well balanced via even throttle. I would get a nice balanced ride until the rear hit the bump stop then the rear would come around. This is much different than the entry/mid corner oversteer from my stock shocks. Jackson also agreed that the stock setup exhibited these characteristics so I'm not sure why some people say a stock Z oversteers and some say it understeers. Maybe it's an 03 vs 04 thing. I also have the evo camber arms up front which give more more grip up front than stock.
At any rate, I have made my adjustments and gained a little over an inch of rear travel so I think I will be golden next time out. I'll be putting some zip ties on shock to measure the travel as well.
You know it right away when you make an adjustment for the worse. The first adjustments I was making at the track were to try and tame the exit oversteer in turn 2. I added rebound to the front and took compression out of the rear per Jackson's recommendation (this was before we realized I was hitting the bump stops). This adjustment definately changed the way the car turned in. When I added a second click the car felt more skittish on turn in, settled down nicely at apex and oversteered on exit. Since we didn't realize the problem was rear shock travel, the changes we were making were not helping at all
For my next day at the track, I brought the settings back to baseline for the first session. I decided to add one more click of compression too settle the car more for the high speed dip of turn 8. It made a difference as the car felt more planted in this 95mph mid-corner bump. The best way to describe one click is that you don't really feel the difference in the way goes through the bump and rebound settings but at the limit, the car behaves ever so slightly differently. At 2 clicks, the car more noticeably oscillates differently over bumps.
Zillinois, as I mentioned my oversteer was caused by hitting the rear bump stops. This is why I only had this problem on the one long speed corner. The rest of the track was perfect. Corner entry and apex were very well balanced via even throttle. I would get a nice balanced ride until the rear hit the bump stop then the rear would come around. This is much different than the entry/mid corner oversteer from my stock shocks. Jackson also agreed that the stock setup exhibited these characteristics so I'm not sure why some people say a stock Z oversteers and some say it understeers. Maybe it's an 03 vs 04 thing. I also have the evo camber arms up front which give more more grip up front than stock.
At any rate, I have made my adjustments and gained a little over an inch of rear travel so I think I will be golden next time out. I'll be putting some zip ties on shock to measure the travel as well.
07-11-2005, 12:40 PM
#15
Thanks for the writeup Dave. It sounds like a very promising setup. I know exactly what you're talking about on T8. Isn't it even worse going in reverse because we're picking up so much more speed (downhill)?
Did you ever have the mid-corner oversteer on T4 at Thill? I'm wondering whether if my softer Hotchkis rear springs are causing me to bottom out there? I swung my rear end there last month. But, then again, I did try the stiff/stiff setting on the hotchkis sways. Since then, I've put it back to med/med.
Looking forward to reading additional feedback on this truechoice/Unitech package. 10's at Thill is pretty impressive.
Did you ever have the mid-corner oversteer on T4 at Thill? I'm wondering whether if my softer Hotchkis rear springs are causing me to bottom out there? I swung my rear end there last month. But, then again, I did try the stiff/stiff setting on the hotchkis sways. Since then, I've put it back to med/med.
Looking forward to reading additional feedback on this truechoice/Unitech package. 10's at Thill is pretty impressive.
07-12-2005, 08:02 AM
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T4 is off camber and crowned so if you don't stay on the inner half of the track you will spin regardless of your setup . Next time you go there, notice all the skid marks running of the track at that point. Keep that rear end weighted and use throttle steer to get that little bit of rotation.
Rknight, I've got the evo sways.
I played with settings a little more on the street this week. I think I'm finally getting a feel for what they do. Rebound makes the car stay flatter and feel stiffer over bump, but in a different way then compression. I think I have a handle on what the difference is and am getting better at adjustments. The upper mounts or something is making some more noise so I'll have to take them off and re-thighten at some point.
. Next time you go there, notice all the skid marks running of the track at that point. Keep that rear end weighted and use throttle steer to get that little bit of rotation. Rknight, I've got the evo sways.
I played with settings a little more on the street this week. I think I'm finally getting a feel for what they do. Rebound makes the car stay flatter and feel stiffer over bump, but in a different way then compression. I think I have a handle on what the difference is and am getting better at adjustments. The upper mounts or something is making some more noise so I'll have to take them off and re-thighten at some point.
07-15-2005, 09:45 AM
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Did a little run in the hills this week. The front of the car bottoms out before hitting the bump stops. doh!
I might take the part of the bump stop that I cut out of the rear and put it on the front.
This is probably happening because I am using the softest compression settings for the street. This hasn't happened on the track with the adjustments turned up. I'll be at infineon soon which has some good compression turns that will test out my travel.
I might take the part of the bump stop that I cut out of the rear and put it on the front.
This is probably happening because I am using the softest compression settings for the street. This hasn't happened on the track with the adjustments turned up. I'll be at infineon soon which has some good compression turns that will test out my travel.
07-15-2005, 11:55 PM
#19
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I just had the Hotchkis Sways (Front Med/Rear Soft) and the Koni Yellow shocks installed. I've had them on the lowest setting since the beginning of the month, and I'm finding them to be underdamped (IMO anyway). I will be changing them to 1/2 way stiff after my first AutoX with the new setup on Sunday.
Daveh:
Are the Koni shocks used in the Unitech setup similar to the Koni Yellows, or are they custom? I'm hoping to learn more about what people with Koni's are running, but I haven't found much info.
Also, I've done a couple track days with Speedventures and Trackquest at both THill and Laguna, and wouldn't mind riding with an instructor who also has a Z
Any idea when you might be up @ Thunderhill again?
-D'oh!
Daveh:
Are the Koni shocks used in the Unitech setup similar to the Koni Yellows, or are they custom? I'm hoping to learn more about what people with Koni's are running, but I haven't found much info.
Also, I've done a couple track days with Speedventures and Trackquest at both THill and Laguna, and wouldn't mind riding with an instructor who also has a Z
Any idea when you might be up @ Thunderhill again?
-D'oh!
07-16-2005, 07:34 AM
#20
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Doh lond time no see
I have the Koni yellows and I run the Evo Sways on med plus Konis on med. really well balanced with I believe your 265's all around.
I have moved to SM2 due to my mods. I was not sure If I was going to go to Candelstick tomorrow but if you are there I am reconsidering. I have made a ot of mods to my car for track days.
Ray
I have moved to SM2 due to my mods. I was not sure If I was going to go to Candelstick tomorrow but if you are there I am reconsidering. I have made a ot of mods to my car for track days.
Ray