Competition alignment and ride height

[GTSilver]

I would like to have your input and based on track experience what do you think of my alignment and ride height settings.

My car is a viper ta with MCS suspension, spherical bearing conversion, shock relocation and running Michelin slicks on 18x12 front wheels and 18x13 rear wheels. Running in Bahrain international circuit which is a F1 circuit which has smooth surface, slow and high speed corners and elevation changes.

I'm about to install them in the next couple of days and will be my first time trying these mods on the car. Previously I was running OEM suspension and running OEM ride height as it isn't adjustable and these alignment settings:

Front:

Camber: -3 to -3.25 degrees
Caster: honestly I didn't gave it much attention and used to run both side equal to eachother
Toe: 2 mm per side toe out

Rear:

Camber: -2.5 to -2.8 degrees
Caster: The same as above I just kept them equal both sides
Toe: 1 mm per side out

These above settings were on Michelin and Pirelli slicks on 18x12 front wheels and 18x13 rear wheels.

From what I gathered and read here in the forums that caster is very important and very sensitive to the viper so I'll look into what figures to run. In regards to my alignment settings the majority that I have spoken to mentioned that my figures are aggressive but the reason behind that is due to me running slicks which work better with more camber and the toe figures although might be a key to the car being a bit loose than my liking it helps a lot to get rid of the understeer and help with better rotation if you know what I mean.

However now with the suspension changes I would to try a different alignment as I'm still having an issue getting the power down especially at the apex and this is loosing me time and would like to fix that.

Can you please share what had worked for you especially who has been tracking vipers for a while especially ACR's, ACRX and comp coupes. Also what are your thoughts if I should run what I was running previously. In regards to ride height I'm looking to run 4" in the front and 5" in the rear with the MCS.


Looking forward to your inputs.

Thanks
Yousif

[kriskyk]

What is the shock relocation you mentioned?

[GTSilver]

What is the shock relocation you mentioned?

These are A-Arm mounted lower shock mounts help realign the shock angle in cars with lowered suspension.

[Arizona Vipers]

I've just had the same suspension mods done and I am also running the MCS suspension. I have only ran it once since this setup and blew a shock. Now waiting for the Extreme cam to be installed by Arrow.
When I ran it, I ran the ACR alignment specs, (I'm running ACR-E aero) but slightly lower ride height. 5" is good in the rear, you could probably get lower. You are not running any diffuser or front splitter? I'd say you could go down to 5" rear and 3.75" front, maybe even a bit lower in the front. What spring rates are you running?
Finally which compound Michelins are you running? I ran them and didn't like how much slower they got after the first heat cycle. You didn't experience that? I like the Pirelli's much better.

[kriskyk]

I just ordered the MCS Suspension, who makes the shock relocation mounts?

Are they only needed if the car is significantly lowered?

[Arizona Vipers]

I just ordered the MCS Suspension, who makes the shock relocation mounts?

Are they only needed if the car is significantly lowered?

they aren't need at all. Don't do this unless you're a hardcore track guy.

[kriskyk]

Can you elaborate a bit on when it makes sense to do this?

I'm having the MCS Suspension installed along with the stiffer sway bars, adjustable endinks, some custom aero bits and would like to get everything done the first time around....

[Racingswh]

Toe out in the rear just seems wrong to me. I never toe my cars out in the rear.

Camber is set by tire temps. With hot pressures in the low 30's take three temps on each tire with a probe style tire pyrometer as soon as you pull in off the track and see where they fall.

https://nasaspeed.news/tech/wheels-t...the-racetrack/

[Dan Cragin]

I would suggest an asymmetrical alignment depending on the track you run (clockwise, counterclockwise), tire temps will tell the story.

The rear shock clevis relocation done on the Comp Coupes helped improve rear wheel travel and geometry.

Never toe out in the rear. The only time I did that was for the Mopar Formula drift Viper.

We always run as much front caster as possible. It improves grip and steering feel.

If you are still running eccentrics on the control arms, switch to shims.

Bump steer the front and rear of the car at ride height.

Corner weight the car with how much fuel you will have half session and ballast for your weight in the driver's seat.

Run nitrogen in the tires, 36 psi hot seems to be as high as the Hoosiers like (There are differences of opinion).

Always start a weekend on new tires if you are going to run 2 days and want the best times. Manage your tires when new,
give them a short heat cycle and let them sit (better with tires off the ground).

Hope this helps. Opinions vary.

[ayousef]

okay maybe not helping answer the question but why all the mods without adding aero downforce to the car?

[kriskyk]

Are the control are shims really necessary?

[GTSilver]

I've just had the same suspension mods done and I am also running the MCS suspension. I have only ran it once since this setup and blew a shock. Now waiting for the Extreme cam to be installed by Arrow.
When I ran it, I ran the ACR alignment specs, (I'm running ACR-E aero) but slightly lower ride height. 5" is good in the rear, you could probably get lower. You are not running any diffuser or front splitter? I'd say you could go down to 5" rear and 3.75" front, maybe even a bit lower in the front. What spring rates are you running?
Finally which compound Michelins are you running? I ran them and didn't like how much slower they got after the first heat cycle. You didn't experience that? I like the Pirelli's much better.

No still running OEM TA 1.0 aero, I'm running 600/900 springs, running S8L compound and no I didn't experience a drop in performance that drastic but eventually they do as with all slicks. Regarding rake I have to see if it'll clear and wont be any rubbing.

I just ordered the MCS Suspension, who makes the shock relocation mounts?

Are they only needed if the car is significantly lowered?

I got them from Jeff Stout at Complete Performance Motorsports.

okay maybe not helping answer the question but why all the mods without adding aero downforce to the car?

Well I've driven a couple of aero cars and it takes a while to get the hang of it and use the aero properly. I wanted to get comfortable with the car without adding the effect of aero which will eventually ne the case down the line.

[GTSilver]

I would suggest an asymmetrical alignment depending on the track you run (clockwise, counterclockwise), tire temps will tell the story.

The rear shock clevis relocation done on the Comp Coupes helped improve rear wheel travel and geometry.

Never toe out in the rear. The only time I did that was for the Mopar Formula drift Viper.

We always run as much front caster as possible. It improves grip and steering feel.

If you are still running eccentrics on the control arms, switch to shims.

Bump steer the front and rear of the car at ride height.

Corner weight the car with how much fuel you will have half session and ballast for your weight in the driver's seat.

Run nitrogen in the tires, 36 psi hot seems to be as high as the Hoosiers like (There are differences of opinion).

Always start a weekend on new tires if you are going to run 2 days and want the best times. Manage your tires when new,
give them a short heat cycle and let them sit (better with tires off the ground).

Hope this helps. Opinions vary.

The issue is the event is carried over 2 days on 4 different track layouts, so the idea of asymmetrical alignment might not be working as we would wish. I've switched to shims rather than eccentrics. I've never ran nitrogen in the tires and wanted to know what cold pressures to run ? Thanks for your input.

Are the control are shims really necessary?

From my understanding it helps with setting the alignment settings and keep them from moving under any loads by driving.

[Arizona Vipers]

The issue is the event is carried over 2 days on 4 different track layouts, so the idea of asymmetrical alignment might not be working as we would wish. I've switched to shims rather than eccentrics. I've never ran nitrogen in the tires and wanted to know what cold pressures to run ? Thanks for your input.



From my understanding it helps with setting the alignment settings and keep them from moving under any loads by driving.

You don't want to be over 32psi in those Michelin's, ever. I would start 19-21psi depending on the track and end up around 29 hot. My 2nd heat cycle was MUCH slower on the Michelin's, IMO they are one hit wonders. That "endurance" compound is really meant for one long heat cycle. Trust me when I say the Pirelli's will last much longer. Plus you get a much bigger sized rear. Your rear Michelin is only a 305, not sure if you realize that.
The shims are a good idea especially when running slicks. My alignment was moving on both my ACR and my '13 until I did the shims.

[GTSilver]

You don't want to be over 32psi in those Michelin's, ever. I would start 19-21psi depending on the track and end up around 29 hot. My 2nd heat cycle was MUCH slower on the Michelin's, IMO they are one hit wonders. That "endurance" compound is really meant for one long heat cycle. Trust me when I say the Pirelli's will last much longer. Plus you get a much bigger sized rear. Your rear Michelin is only a 305, not sure if you realize that.
The shims are a good idea especially when running slicks. My alignment was moving on both my ACR and my '13 until I did the shims.

I always run 30psi hot on the Michelins, and yes start with very low cold pressures. What size Michelins are you running ?

[Arizona Vipers]

I always run 30psi hot on the Michelins, and yes start with very low cold pressures. What size Michelins are you running ?

30-65-18 front
31-71-18 rear

That's what you're running, correct?

[GTSilver]

30-65-18 front
31-71-18 rear

That's what you're running, correct?

Yes correct but the rear aren't 305mm as you mentioned earlier they are 347mm.

[Arizona Vipers]

Yes correct but the rear aren't 305mm as you mentioned earlier they are 347mm.

No, it's a 310. That's what the "31" stands for. Just go look at how skinny it is, you didn't notice? The 347 is the width of the outer sidwalls. It's a skinny tire. It's still much faster than a 355 street tire.
If you go with the Pirelli's you can get 325 wide front and rear:
325-65-18 fronts
325-70-18 rears

[GTSilver]

No, it's a 310. That's what the "31" stands for. Just go look at how skinny it is, you didn't notice? The 347 is the width of the outer sidwalls. It's a skinny tire. It's still much faster than a 355 street tire.
If you go with the Pirelli's you can get 325 wide front and rear:
325-65-18 fronts
325-70-18 rears

Check the below links for the sizes of both Michelin and Pirelli as they are very similar in size just a couple of mm difference.

https://michelinmotorsport.com/Tyres...Sedan-GT/Slick

http://samotorsporttyres.com.au/prod...-p-zero-slick/

[Arizona Vipers]

Check the below links for the sizes of both Michelin and Pirelli as they are very similar in size just a couple of mm difference.

https://michelinmotorsport.com/Tyres...Sedan-GT/Slick

http://samotorsporttyres.com.au/prod...-p-zero-slick/

I've run both of these tires have had them side by side the tread of both tires are like the size they list, 310 vs 325. Although to me though the Pirelli looks much much bigger than just 15mm. The Michelin is "tiny". The 13" wide wheel does help stretch the 310mm out though. But still looks like a bicycle tire on the Viper lol.

[GTSilver]

I've run both of these tires have had them side by side the tread of both tires are like the size they list, 310 vs 325. Although to me though the Pirelli looks much much bigger than just 15mm. The Michelin is "tiny". The 13" wide wheel does help stretch the 310mm out though. But still looks like a bicycle tire on the Viper lol.

I've run both of them as well, I actually haven't noticed it but will check and see. Back to topic how do you like the ACR alignment ? have you run it before adding the aero ? As I'm having an issue putting the power down and would like to try to resolve it.

[Arizona Vipers]

I've run both of them as well, I actually haven't noticed it but will check and see. Back to topic how do you like the ACR alignment ? have you run it before adding the aero ? As I'm having an issue putting the power down and would like to try to resolve it.

The ACR alignment works great with and without aero. It's what I run, except for minor adjustments on front and rear camber depending on the tire widths I'm running. You should have no problem putting the power down, again it's the Michelins. How many heat cycles do you have on them? Mine dropped 2 seconds on a small track on their 2nd heat cycle and then got much worse from there. If you are trying to qualify or break a track record, the Michelin's are great for that, but not much else.

[GTSilver]

The ACR alignment works great with and without aero. It's what I run, except for minor adjustments on front and rear camber depending on the tire widths I'm running. You should have no problem putting the power down, again it's the Michelins. How many heat cycles do you have on them? Mine dropped 2 seconds on a small track on their 2nd heat cycle and then got much worse from there. If you are trying to qualify or break a track record, the Michelin's are great for that, but not much else.

Actually in some parts the rear kicks out even with the Michelins, thus I would like to run a different alignment to be able to put the power run. I'm going to run a fresh set for my time attack competition.

[Arizona Vipers]

Actually in some parts the rear kicks out even with the Michelins, thus I would like to run a different alignment to be able to put the power run. I'm going to run a fresh set for my time attack competition.

Howe long is the track in you time attack competition? How many laps do you get? Do you get more than one session that counts?

[GTSilver]

Howe long is the track in you time attack competition? How many laps do you get? Do you get more than one session that counts?

Its covered over two days on 4 different tracks. Each track is an open session of 3 hours were you can set your fastest lap and every lap counts. 2 tracks are in the one minute lap time, the other 2 tracks are in the two minute range.