[TRZ06]

Originally Posted by travislambert

I'm going to to keep the DSSVs for now. I'd hate to think I did all of that work to give up on it after 2 track days.

Over the winter I hope to get some wider/lightweight 19" wheels. Maybe HREs or Forgelines.

I've also been toying with the idea of a 2.3 supercharger swap. I have a lot of research to do before making that leap though.

Wow, quite the project.

Do you think it might be worth the upgrade to the ZL1 1LE? Sounds like you are headed down that path. Why not just go that route and then you have a warranty still intact.

I am sure you could recoup most of the DSSV costs.

[TRZ06]

Originally Posted by TRZ06

Wow, quite the project.

Do you think it might be worth the upgrade to the ZL1 1LE? Sounds like you are headed down that path. Why not just go that route and then you have a warranty still intact.

I am sure you could recoup most of the DSSV costs.

Nevermind, sorry. I keep thinking you have the SS 1LE, but you have the ZL1.

[vtirocz]

This is excellent information and a big help for me. Thanks for sharing the install pics, data/analysis, and thoughts on the suspension change (both positive and negative)!!

I wonder if handling capabilities are actually reduced on the street (rougher surfaces) when not running the track tires, as compared to the stock FE4 suspension? I'm also wondering if it would be beneficial to run a lower spring rate (proportionally lower front and rear) with the FEA setup?

For my base suspension (non-MRC) SS that's used as a 3-season daily driver (anticipating some track days), I think you've convinced me that the FEA suspension kit is not for me. I'm leaning toward this setup: SS lowering kit (springs/shocks-84188726) + handling kit (swaybars/front links-84242386) + SS 1LE wheels/tires.

[travislambert]

anti-

Originally Posted by vtirocz

This is excellent information and a big help for me. Thanks for sharing the install pics, data/analysis, and thoughts on the suspension change (both positive and negative)!!

Glad you found it helpful.

If I get time I may add some more data. The data I posted likely doesn't tell the whole story. I think "time on throttle" comparisons, etc. might be good. If you guys have ideas, shoot them my way.

Originally Posted by vtirocz

I wonder if handling capabilities are actually reduced on the street (rougher surfaces) when not running the track tires, as compared to the stock FE4 suspension?

It sure does feel that way.

Originally Posted by vtirocz

I'm also wondering if it would be beneficial to run a lower spring rate (proportionally lower front and rear) with the FEA setup?

Interesting thought... I was wondering about what difference a stiffer front anti-sway bar might make with the FEA... e.g., the FE4 front bar. Of course the whole reason I went with this setup is because it was a complete package offering with validation. I think someone else will need to be the guinea pig for this one.

[tomster]

Originally Posted by travislambert

Here are my thoughts on the suspension swap...

Let's get the cradle bushing out of the way...

The only Noise, Vibration, and Harshness (NVH) increase I noticed was after a hard shift. There is a small driveline clunk noise from the ring and pinion that seems to resonate up. Other than that, I haven't noticed any additional noise from the rear on the street or the track. The upside is a nice improvement to the car's behavior on hard corner exits. I also noticed in a straight line when the car's rear tires break free into a spin, the rear doesn't get "squirrelly" when the tires recover and grab. I seem to recall and occasional kick feeling before in this scenario. Overall, this is probably a nice improvement for the hardcore drag-strip or road course enthusiast. For the occasional dragstrip test-n-tune or HPDE attendee, I'd wouldn't bother. This is a very involved installation, and the difference isn't worth the investment for the average Joe. Enjoy your car and save your money for tires.

On to the remainder of the FEA suspension...

Let's start with the street driving. After having both the FE4 and FEA suspensions, I have a better appreciation for the level of comfort provided by the FE4 suspension. The difference is night and day. My buddy who owns the other ZL1 in the picture has owned other vehicles with pretty stiff suspensions. He was considering the FEA swap, but he took a short street ride with me and was immediately convinced the FEA suspension was not for him.

For me, this car is not nearly as fun on the street because of the poor ride quality. At first, I remember thinking this isn't so bad, but the smile slowly faded from my face with each mile. It doesn't take long before the bumps start to get pretty annoying and the obscenities start flying with each jolt to the spine. Had I started with the FEA I might have a different perspective, but I was spoiled by the FE4. There's certainly no improvement in street performance to justify the FEA ride quality sacrifice. The FE4 is WAAAAY better on the street in every measure as far as I'm concerned. If you are thinking about this swap and you drive more miles on the street than on the track, I'd strongly recommend against it. Don't get caught up in the DSSV marketing etc.. Just remember the FE4 is fantastic on the street and the track, and some of the best performance cars in the world use magnetic ride control.

And... if you happen to have the FEA suspension, be honest when people ask you about it. The ride quality is pretty terrible and nobody is going to take your man card for calling it what it is. For those who say the FEA is not that bad, I challenge you to drive a car with the FE4 suspension and then go back to the FEA.

Before moving to the track review, let me say this review is NOT meant to be a comparison of the ZL1 and the ZL1 1LE. I intend for this to primarily be a comparison of the FE4 and the FEA suspensions on a ZL1 specifically at the PittRace track. Please keep this in mind for any comments you have.

First a couple notes:

• The air temperatures for both FEA track days were much cooler than the FE4 track days, ~60-65F vs ~85-90F.
• The front spring preload was set in the "nominal" position (in the middle).
• The rear stabilizer bar started in the neutral setting (in the middle hole).
• Tires were Hoosier R7s in the stock ZL1 size; 285/30/20 front, 305/30/20 rear
• Alignment
  FE4 -2.9 Front Camber, -1.8 Rear Camber, 0.12 Total Front Toe, 0.07 Total Rear Toe
  FE4 -3.5 Front Camber, -2.0 Rear Camber, 0.00 Total Front Toe, 0.10 Total Rear Toe
• I didn't get many clean laps all weekend, so the laps I need to use for comparison ended up being in two different PTM modes. The FE4 laps were ran in Sport 1 and the FEA laps were ran in Race.

The first FEA track day was spent getting a feel for the car. The car was much more neutral than I was used to. The stock FE4 has significant understeer characteristics, but the FEA was much more neutral with some oversteer on corner exit. I didn't notice any real difference in ride comfort on the track, but who cares about ride comfort on the track anyway, right?

My best time for the first day was about 2 seconds off pace from my best time with the FE4 (I misplaced the SD card I was using Saturday, but I have a good idea of my times.) Honestly, I was a little frustrated having sacrificed significant street driveability with no track performance improvements to offset the sacrifice.

For the second day, I adjusted the rear stabilizer end-link forward to the softer position and did my best to keep the rear tires a couple PSI lower than the front. I was blown away by what difference this made. After this adjustment, the car was very neutral. I immediately was back to running about the same as the FE4 suspension, but without the tire destroying understeer. When it was all said and done, I achieved a new personal-best time of 1:52.97. That's a whopping 0.85 seconds faster than my FE4 personal-best that was ran in 30 degree warmer air. I'd call that effectively the same given the temperature difference.

Looking at the lateral acceleration chart, I don't see a significant difference between the grip levels achieved with the FE4 vs FEA. However, it appears the tires are wearing much more evenly with the added stiffness and camber.
FEA in Red
FE4 in Blue

Attachment 958126

At this is time, I don't believe the FEA by itself offers a significant track performance improvement over the FE4. Is the FEA better for the track? Without a doubt, but the benefits I see are ancillary (tire wear, wider tire/wheel options, weight savings, etc.). For an analog device, I think it's amazing that the DSSVs can offer comparable performance to an electronic ride control system. Just don't expect the suspension swap alone to immediately reduce lap times, because it probably won't happen.

Here's the FE4 Lap:


Here's the FEA Lap:


I have lots of data, so if there's something specific you'd like to see let me know.

Thanks for reading!


--------------------------------------


Below are some preemptive rebuttals:


Umm... Maybe, but I don't think so. I think wider tires would make a bigger difference and the aero would be track dependent. It takes a really high-speed turn to realize an improvement from the aero, and PittRace only has one of those. On the other hand, it has 4 high-speed straights where the wind resistance required for the downforce works against you. There's only one turn that I believe the added downforce would be significantly beneficial (turn 16). Comparing my lateral acceleration data with tomster's ZL1 1LE run at PittRace, you can see there's not a huge difference. Tom is clearly one hell of a driver so there's that. Also, Tom has wider tires than I'm running which would account for some of the delta. So what's that leave for the aero benefit? Please feel free to prove me wrong with data. Until then, here's my data:
ZL1 in Red
ZL1 1LE in Blue

Attachment 958143


Remember we're not specifically comparing the ZL1 to the ZL1 1LE, but if Chevrolet ever put the Supercar 3R tires on the A10 ZL1 and made the secret sauce PTM adjustments to match, my money would be on the A10. My advice...Don't get tangled up in all of the marketing. Make no mistake, it's marketing. There are plenty of good tracks much closer to Detroit, but some marketer somewhere has decided the best way to sell a sports car is with a good Nurburgring time. All the engineers have to do is achieve times for each car in the correct order. Once they achieve the desired results, they quit testing. For this reason I don't put a lot of stock into those times.


This may be true, but what if I had more time with the FE4? I feel the laps with both suspension setups are respectable and comparable. Randy Pobst was at PittRace over Labor Day weekend and I believe his best lap in a Camaro SS (non-1LE with the FE4 including wheels/tires) was a 1:58. Of course he could do better given some time, and I'm sure he could beat my lap times with my car.... but my point is there's not an enormous amount of room for improvement in the test laps I'm considering for either suspension setup.

Very Interesting couple notes:
*supersized you went softer on the rear bar as my car pushed Mid corner until i moved the bar to full stiff
*My car also over steers off corner however I feel like its do to the ELSD you cant adjust it out. I had to change my driving habit to compensate for this. I really couldn't understand it fully until i turned traction full off at an event. when you roll on to the throttle the car rotates making you think its about to step out however most of the time you can keep in it and drive through it. (its hard to explain and harder to get use to) you feel it more in high speed corners. low speed corners like the last turn on Pit it will step out on throttle almost like you have a spool in the rear end.
* I agree Arrow helps you very little if at all at Pitt
* I have only run Pitt 3 times twice in my 13 ZL1 and once in the 1LE however fast times at this course require guts I am sure i have .5 to a full second if was willing to push a couple area's harder.
* I have drove both FE4 and FEA extensively at Mid Ohio and agree that its the tires that make the difference both suspensions perform very well
*I believe the largest benefit to FEA is better compliance with larger sticker tires.
*The Loss of Ride is not worth the minor gains in my opinion.
*Thanks for the Driving Props However I know I have many places I could be doing better
* I would love to learn more about how you use the data to improve lap times. I use Cosworth but it seems you could do more with pi if i knew how to use it. Most of my tuning is Seat of Pants feel and lap time.

[Badgerbimmer]

Travislambert great review and comments. Confirms my thoughts to just leave the car alone but for tires and the solid cradle bushings. Seems like high performing springs and better MRC calibration options are the way to go if and when they become available.

As a note, from everything I have read, to this point it seems like DSC hasn't hit the point to justify the cost of their MRC controller.

[RUQWIKR]

What was the total weight savings being the lighter swaybars and DSSV's? Nice smooth laps in both videos. Will be good to see a PTM Sport 1 run with the DSSV's in similar air conditions, too.

[travislambert]

Originally Posted by RUQWIKR

What was the total weight savings being the lighter swaybars and DSSV's?

I'm not 100% sure, but I'm thinking it should be a 40+ lbs savings.

Originally Posted by RUQWIKR

Will be good to see a PTM Sport 1 run with the DSSV's in similar air conditions, too.

There's a good lap in this video from the same day starting around the four minute mark.

[TRZ06]

Originally Posted by Badgerbimmer

Travislambert great review and comments. Confirms my thoughts to just leave the car alone but for tires and the solid cradle bushings. Seems like high performing springs and better MRC calibration options are the way to go if and when they become available.

As a note, from everything I have read, to this point it seems like DSC hasn't hit the point to justify the cost of their MRC controller.

Agreed regarding the DSC Controller. From all the info. I have gathered, all they are doing are changing the values of when the shocks does what it does stock. Some say it makes the car feel less stable because they are softening up the shock initially.

In order for MRC to get better than what it is stock, you would have to re-shape the tuning curve of the shocks and make them react even faster to recover when the suspension gets upset mid-corner.

For an example of this, take a ride in a high-end coilover setup and see how fast the shocks recover when upset, this is how a MRC tuning would make it better, not simply just softening up the ride and changing when the stock tuning happens, like DSC does.

[RUQWIKR]

Originally Posted by travislambert

I'm not 100% sure, but I'm thinking it should be a 40+ lbs savings.



There's a good lap in this video from the same day starting around the four minute mark.

Car looks consistent and stable in both SPORT 1 and RACE. Track looks fun and smooth compared to many tracks I've watched video of.

[Chris V]

Originally Posted by TRZ06

Agreed regarding the DSC Controller. From all the info. I have gathered, all they are doing are changing the values of when the shocks does what it does stock. Some say it makes the car feel less stable because they are softening up the shock initially.

In order for MRC to get better than what it is stock, you would have to re-shape the tuning curve of the shocks and make them react even faster to recover when the suspension gets upset mid-corner.

For an example of this, take a ride in a high-end coilover setup and see how fast the shocks recover when upset, this is how a MRC tuning would make it better, not simply just softening up the ride and changing when the stock tuning happens, like DSC does.

You can't change the hardware side of how fast the MRC fluid responds with the DSC, but you can tune the shock to do anything you want in terms of compression and rebound (high/mid/low speed) and factor in dynamic vehicle loads to compensate as well.

You should give the DSC a try, it's pretty awesome. I've never felt like my car was less stable than stock, and it's a night and day difference at autocross. On track the stock shock calibration is really good, so the difference is less noticeable.

[TRZ06]

Originally Posted by Chris V

You can't change the hardware side of how fast the MRC fluid responds with the DSC, but you can tune the shock to do anything you want in terms of compression and rebound (high/mid/low speed) and factor in dynamic vehicle loads to compensate as well.

You should give the DSC a try, it's pretty awesome. I've never felt like my car was less stable than stock, and it's a night and day difference at autocross. On track the stock shock calibration is really good, so the difference is less noticeable.

Exactly my point. To me, it is a waste of money. If it actually made the shock perform better and quicker, it would be worth it.

To just monkey around with the stock calibrations, seems cheap. High end engineers at GM already did the hard work.

I do not autocross, I care more about how quickly the shocks recover when upset where it really matters... when you are going really fast.

Anyways, I am not complaining, I am happy with the stock MRC. I just do not think the DSC Controller is worth the money.

[Chris V]

Originally Posted by TRZ06

Exactly my point. To me, it is a waste of money. If it actually made the shock perform better and quicker, it would be worth it.

To just monkey around with the stock calibrations, seems cheap. High end engineers at GM already did the hard work.

I do not autocross, I care more about how quickly the shocks recover when upset where it really matters... when you are going really fast.

Anyways, I am not complaining, I am happy with the stock MRC. I just do not think the DSC Controller is worth the money.

The hardware is fine - it’s milliseconds response time - that’s not a weak link.

The same hardware is in the Mustangs and many other platforms, the calibration is what sets them apart.

“The shocks recover when you are going really fast”? What do you mean? Wheel velocity or shaft velocity? Adjustability is a huge factor in achieving the right dynamics. The OEM calibration is designed to hit a target. If you start changing parameters you will exceed that target.

In my case I’ve added a bunch of wheel and tire, spring rate, and power.

[vtirocz]

Has anyone owned both a 5th gen Z28 and a 6th gen ZL1 1LE. Is the 6th gen DSSV setup more harsh on the street than the 5th gen?