S550 mavisky's "LOUDCAR" Build Thread Profile - S550 Mustangs

[mavisky]

I would suggest trying to add more rear bar before softening the front. You need all of the front roll stiffness possible to help the soft front springs. With aero now you could add more rear bar than you think. The only point you have too much rear bar is when you start getting excessive inside wheelspin.

I've come to the realization that I'm on a compromised setup at the moment and will be changing springs. I'm at max rear bar right now so backing down front bar is my only option without removing and swapping parts. If i'm going to be removing and swapping parts then it's the springs that are getting replaced as the bars should be acceptable for the correct spring setup.

 

[mavisky]

I've been discussing with other competitive autocrossers with this chassis and they're suggesting 600lb front springs.

I'd been looking at the 500lb 2.5x7" Hypercoil springs for AJ's setup since he only offers a 400lb max spring offering.

AJoffers a 1200lb rear that I thought would be similar to the high end of what I've got at the rear from the Steeda dual rates.

According to Steeda these are the rates for the dual rates so this would significantly stiffen the front while keeping the rear about the same which should allow me to dial out a lot of front bar and dial up some rear bar.

Dual rate springs
220 - 350 - Fronts
800 - 1200 - Rears

Steeda competition bars
Front 1.5" bar vs Mustang GT bar - 42% stiffer - 97% stiffer
Rear bar vs Mustang GT bar - 23.6% softer - 13.1% stiffer

This month I ran these above rates and the Steeda competition bars at two events. First event was full soft on the bars front and rear (front bar can only be run at position 3 of 4 due to ride height sensors). Car was neutral, but felt like I was standing up in a canoe with all that body roll.
350lb front
1200lb rear
Front 1.5" Bar at 42% stiffer
Rear Bar at 23.6% softer

Last event I moved both bars to full stiff and the car had pronounced understeer almost everywhere. I couldn't really get the car to oversteer anywhere.
350lb front
1200lb rear
Front 1.5" Bar at 97% stiffer
Rear Bar at 13.1% stiffer

This event this weekend I've dialed the front bar down to the middle notch for the next event while keeping the rear stiff to see how that works out.

I'm thinking the move would be the following
600lb front
1200lb rear
Front 1.5" Bar at 42% stiffer
Rear Bar at 13.1% stiffer

 

[Ewheels]

I almost pulled the trigger on a Steeda competition rear bar but then I saw a post on the TMO facebook page about a guy's Steeda rear bar completely shearing in two. Apparently that's not uncommon....
I guess the point of this is words of warning.

 

[mavisky]

I almost pulled the trigger on a Steeda competition rear bar but then I saw a post on the TMO facebook page about a guy's Steeda rear bar completely shearing in two. Apparently that's not uncommon....
I guess the point of this is words of warning.

Living in the south means that corrosion isn't a concern for me.

 

[EF1]

Living in the south means that corrosion isn't a concern for me.

I agree. The ones I have seen broken look like they were rusted through.

 

[Ewheels]

Should have figured rust could've been the culprit

 

[mavisky]

Ran a new event today with Atlanta Motorsports Park where they ran an autocross style event using a portion of their actual track. The classification system they use has only 3 classes that basically break out to Miata type cars, everything else under 475whp, and then anything above that or lightweight snd big power like turbo Miatas or in our case a Can-Am 900cc turbo side by side on 4 Hoosier slicks.

Finished the event with the second fastest run of the day behind a 1972 firebird wearing 12" wheels, a corvette front suspension and a circle track 3 link rear suspension where you could see the ground through the rear window. Considering I was battling that with a full weight street car I felt pretty decent to only be about a half second back for the second fastest time of the day overall and in class.

Going down one notch on the front bar gave me a car thats very responsive to the front end, but we're still dragging the splitter under heavy straight line braking so this setup is only a bandaid to a better spring setup, but I should be able to make it work the rest of the season.

Made it to about 90 before braking on the uphill section except for the third run where we overcooked it and went two wheels off.

 

[mavisky]

After what felt like forever (6-23-2024 to 8-11-2024) we finally got back to another event. This year I've been working through a lot of minor suspension revisions to find the best balance I can with the equipment I've got. Last event in June saw an increase in that regards after making some swaybar adjustments and I decided to focus this month on some shock calibration changes. I re-mapped the base rates for "race" and built in some digressive valving to the shocks to allow them to try and not get upset too much by the big bumps on the courses we run. This seems to have worked pretty well and I think with a little more refinement I'll have a pretty good setup here. I really wish the datalogging capabilities of the DSC were better or could be more reliably overlayed with video and other logging software. Would really help the process I think.

With those changes in hand we went to face our usual competition (minus 2 top competitors in other classes) and set about remembering how to drive this damned thing. I got a little lucky in that there were some major timing issues and I had 3 runs back to back that didn't count. None of these were my fastest runs but certainly helped me dial in a better line. The same thing happened to some of my top competitors though so this wasn't some magical advantage.

In the end the last run of the day ended up being my fastest. Shocking because after 8 runs in 90 degree heat the poor Yokohamas were probably screaming for mercy despite being sprayed down after every run. The heat was so bad it nuked the go-pro so I don't actually have video of my fastest overall lap. My main competitor in class set his fasted time on his 4th overall run of the day and then slowed down from there. My hail mary last run came through again though and while it wasn't enough to win it was enough to close the gap to under a 1/4 of a second. That margin of error is making me regret those extra trips to the buffet during our July cruise to Alaska LOL. With that final run I ended up with 9th overall out of 106 drivers and 6th overall on PAX adjusted times for classes. Of course the cars ahead were made up of Miatas and CRX's as it's just hard to beat tiny and light weight when it comes to autocross.

 

[Mcanale]

I almost pulled the trigger on a Steeda competition rear bar but then I saw a post on the TMO facebook page about a guy's Steeda rear bar completely shearing in two. Apparently that's not uncommon....
I guess the point of this is words of warning.

I'm almost certain this was me. It was 100% a design flaw and not a rust concern(the car is garaged). Some other guys followed up on the thread and showed theirs breaking in the same spot. It breaks right where the bushing stop is welded on. They must have had too much heat in the weld and made it brittle. I replaced it with a Whiteline bar and their design has the bushing stop bolted on instead of welded.

 

[mavisky]

I'm almost certain this was me. It was 100% a design flaw and not a rust concern(the car is garaged). Some other guys followed up on the thread and showed theirs breaking in the same spot. It breaks right where the bushing stop is welded on. They must have had too much heat in the weld and made it brittle. I replaced it with a Whiteline bar and their design has the bushing stop bolted on instead of welded.

I'll be sure to check mine for cracks or other issues.

 

[mavisky]

Ran another autocross style event yesterday. This is similar to a Pro-Solo style course with mirrored courses and head to head competition, but is run un-timed with a ladder style bracket elimination at the end of the night. Unfortunately only had the opportunity to get 2 practice runs and then one actual head to head run before a storm came in and they had to cancel the event. This was apparently the tightest and most technical course they'd run to date here, but there's only so much room to get wild with two courses inside the small oval.

Pretty happy with my current DSC settings although I was getting a little "pogo-ing" through the first slow tight right hand corner. Not getting it anywhere else so not sure I'll do too much in the way of revisions to address that and I was probably just coming in a little too hot.

 

[CobaltFilly]

The pro is specifically designed to work with a Hans if you'd like, but as you identified though, with just using it for autocross it's not likely to ever have a severe impact posing a concern.

It also has some crash mitigation system built into it allowing the shoulder to rotate like a 3 point belt. Also by using the factory harness plug it still let's the car use all the factory safety mechanisms. Worth a watch on their site.

SAFETY THROUGH TECHNOLOGY » Schroth QuickFit Pro

Do you think I should save my cash and go with Schroth Quickfit II Pro, Hans, the extra sub belts, and a watson lap belt mount in my stock base model seats vs going $5k into CMS roll cage, Sparco EVO XL, seat hardware/mount, HANS and Schroth 6 point harness? I am having a dilemma on spending that right away and am worried that going "full interior racecar" isn't safe for daily driving. Safety is #1 over the money honestly. Thoughts?

 

[GAR944]

That's a pretty good course for the space available.
Your cars sounds great on the overrun.
Not a lot you can really do to get the big barge through a tight course. Just keep working the throttle till it wants to understeer.
Didn't expect to see a Turbo Macan on course but happy to see others do stupid things as well. I've run a Jeep Grand Cherokee on a hillclimb circuit being used for a khanacross. Caus why not. Anything can be a race car for a day.

Don't know if you changed the front springs yet but going from a 350 to 600 you may need a 6' spring given running low. I did a similar change and went from an 8' soft to a 6' hard spring. Made the mistake of 8' spring like what was coming off then realised to get the right height the tyre hit the spring with camber dialed in on the strut leg. Had to get 6' to make it work. I am on a 20' rim though which might make enough difference for your setup. Just a heads up.

 

[mavisky]

That's a pretty good course for the space available.
Your cars sounds great on the overrun.
Not a lot you can really do to get the big barge through a tight course. Just keep working the throttle till it wants to understeer.
Didn't expect to see a Turbo Macan on course but happy to see others do stupid things as well. I've run a Jeep Grand Cherokee on a hillclimb circuit being used for a khanacross. Caus why not. Anything can be a race car for a day.

Don't know if you changed the front springs yet but going from a 350 to 600 you may need a 6' spring given running low. I did a similar change and went from an 8' soft to a 6' hard spring. Made the mistake of 8' spring like what was coming off then realised to get the right height the tyre hit the spring with camber dialed in on the strut leg. Had to get 6' to make it work. I am on a 20' rim though which might make enough difference for your setup. Just a heads up.
View attachment 97905View attachment 97904

Appreciate the heads up. Honestly wouldn't mind a little extra height up front, but good to know there are issues with spring length as I have been concerned about tire clearance with a coilover setup. Even with the 295/35-19 setup and the Steeda Dual Rate Magneride springs on the car I still have to run about 3/8" of spacers on the front to keep it from scraping absolutely everywhere with the splitter.

 

[mavisky]

Do you think I should save my cash and go with Schroth Quickfit II Pro, Hans, the extra sub belts, and a watson lap belt mount in my stock base model seats vs going $5k into CMS roll cage, Sparco EVO XL, seat hardware/mount, HANS and Schroth 6 point harness? I am having a dilemma on spending that right away and am worried that going "full interior racecar" isn't safe for daily driving. Safety is #1 over the money honestly. Thoughts?

Send this over to me through PM as opposed to in this build thread.

 

[ITLRUN]

Very Nice Build! Hello from Adairsville, GA.

 

[mavisky]

Very Nice Build! Hello from Adairsville, GA.

Thank you.

Got some great looking photos from the last event.

 

[ITLRUN]

AMP is my favorite track, but I don't get to visit as often as I would like to. Two of my cars are too loud. But I absolutely have a blast in a very underpowered 2012 V6 car there with a bit of 302S aero. Coming in T16 at 110 mph is buttpuckering in this little car.

 

[Bill Pemberton]

Great shots Man, are you bringing your mean beast to the Solo Nationals in Lincoln, Ne. ? Plenty of TMO members will be there racing and fun place to meet alot of them.

 

[mavisky]

Great shots Man, are you bringing your mean beast to the Solo Nationals in Lincoln, Ne. ? Plenty of TMO members will be there racing and fun place to meet alot of them.

Unfortunately not. Nationals lands on a busy time of the year at work and a multi-day 2,000 mile round trip just isn't in the cards.