S550 Honey Badger GT350 Build Build Thread Profile - S550 Mustangs

[dragoon]

. Yeah - car felt so good on the first day with the decent grip. it really got my hopes up, but then just fell off every session, ha. No worries. I'll have to come back when the car is fully sorted and use up some fresh tires to see what it can do. Data says a 57 is .pretty doable once I get the brakes dialed.

Not sure how clear it is on camera to those who haven't heard it in person, but it makes the most heavenly flames and "bangs" on every up shift. It's so savage and it's really hard not to just overshift the car for the fun of it.


yeah - it really builds speed fast out of corners and through technical sections. and I'm finally getting truly comfortable. still has no TC, so I'm being careful. no need to lose the rear end in the climbing esses at 140+ ha


Ha. i seriously felt bad for a lot of those other drivers. Some of them mustve given me 25+ point bys over the weekend. Car was super quick and the closing speeds with street cars is pretty intense. I only gave one point by all weekend and it was to a 900whp ZL1 1LE on slicks - but he could only do 1 lap at a time

Great stuff in all your posts Kevin !! Will be looking forward till next 4th of July at Road America to hear the new exhaust set up !!
GO LIKE HELL

 

[Dave_W]

Do you think you'll have the TC sorted by Oct. 24?

Tire Rack Ultimate Track Car Challenge

The ultimate test for track cars. The UTCC is a no-holds-barred race to find the fastest race cars in the US.

ultimatetrackcarchallenge.com

Maybe plan ahead for 2025, as it shows 2 cars waitlisted now. Looks like @Fair will be there with his LS-swapped Mustang "Trigger"

Tire Rack Ultimate Track Car Challenge Entries — Tire Rack Ultimate Track Car Challenge

ultimatetrackcarchallenge.com

 

[honeybadger]

Okay - so catching up a bit. Before the trip to VIR, I had a couple of things I wanted to address.

First, I needed to fix the exhaust and get the driveshaft replaced. DSS was able to get a smaller diameter DS with one less adjustable CV - which would have less vibration issues. After that, I needed to get the exhaust figured out. given how loud the "bullet resonators" were, I wanted to try something a bit less chaotic. The resonator-only setup was ridiculous and fun, but it was really fatiguing if you were tired - and I'm always tired on the days I'm instructing.

So I bought some TICON oval race mufflers - these are the 12 overall length ones. I also added a slip joint to help with expansion and give more clearance to the drive shaft.





Here's how the system turned out - basically slip joint to v-band is Ti and everything else is stainless.



This was my first time welding Ti and I'm not a real fabricator to begin with, but I was happy enough with these. As always, fitment matters more than you're welding skill and Ti makes that even more obviously than stainless. Lessons learned for next time - it's better to throw a cut away and get a perfect fitment with a new one than work with gaps if you can help it.




Another thing I wanted to do was change up the cooling system a bit. A couple events ago, I changed from a single 16an outlet out of the driver-side head to dual 12an lines -- one from each head. They then wye into swirl pot. This seemed to help keep temps under better control - specifically at wide open throttle and extended idling.


I used to measure coolant temp and pressure on the radiator, but the angle and placement always had me worried i was going to be capturing an air pocket. So I added a bung to the swirl pot that I know 100% is submerged in water. Got some good data that I'll share in the next post.



Finally, with the SPL arms up front, my previous brake cooling solution wasn't super secure. I had my own version of the brake deflector plates that other vendors sell (like those from Vorshlag). The problem is they're designed to bolt into the three holes in the OEM front tension arm. I was doing some research online for what Porsche does on their GT3s and realized their OEM deflector would probably work since their front OEM arms are round like the SPL parts. I ordered up a set and installed them. Direct zip-tie on!



I have my own version of the OEM brake duct - but the idea is the same. Airflow from the front bumper is directed into the deflector along with air como



Unlike many of the solutions on the market, these direct airflow right into the rotor - not just in the general direction

 

[honeybadger]

VIR - as always - truly is heaven on earth. A track with unparalleled flow and really only equaled by Road America and Road Atlanta.

For those that haven't been, the grounds are beautiful - I can't even imagine how much they spending mowing this place. Uniquely Virginian for sure. Reminds me a lot of Road America.


This was the first event with the new build were I got multiple sessions--in a row--where nothing really went wrong. Each night I did have to lift the car up and tweak the exhaust, but outside of that, she was flawless - as evident by the 140 gallons of e85 I burned and the 9 hours of run time on the track. Ironically, I have fairly limited video as I forgot the SD card for my Aim Smartycam system - I did grab some helmet cam stuff with a new camera. General thoughts:

1. New exhaust makes the car sooooooooooo much more driveable. I hate to admit it because I love loud racecars, but it's not even close to a subtle difference. Its monumental.
2. The car is getting very quick as we dial it in and I get more comfortable driving. Still no TC, so I was being careful. Even then - closing speeds were intense and where it builds speed takes some getting used to. Coming out of snake, I could eat up a couple hundred foot gap on most cars like nothing before the climbing esses
3. This led to another observation - the car is VERY approachable for how much its changed. I found myself comfortably pinching the apex of the first part of the esses at 130mph and still sending it into the esses. I could pretty much pass anyone, anywhere comfortable because the car is so predictable and forgiving
4. Still fighting brake issues - all my brake markers were where they would be in a street car. I've narrowed the issue down - my brake balance is dynamically changing with pedal presssure, causing the ABS to have to step in a lot and keep it from locking tires. Working with tilton now on identifying the issue
5. Even with the aero, this car has plenty of top end - I've 160+ on every big track with it so far (Road America, COTA and VIR). While these are obviously fast tracks, a similarly aero'd GT350 would be in the 146-148 range.

Here are some flybys

Main straight - exhaust sounds great

140 mph into the esses

Other rando photos -

The air jacks and extension stands really got their workout - I had to keep messing with the exhaust. These make it so much safer and easier to work under the car.



One thing I didn't account for is the weight of the new mufflers and the slip joints. It was too much and it kept pulling the mid pipes out of the slip joints. This is a pic of when I got the car home and on the lift - whoops



At least my welds held :crackup:



In other rando stuff -

Front brake pads are done after 15 hours of track time. It might look like a good bit is left, but these started out as 1in thick pads


Cooling is working KILLER now. Coolant temp is peaking at 187 and oil temps at 210 (going into the engine). ONot shown, but oil is 265 coming out of the motor. and CHTs are staying low too. I'm logging at 20hz - which is 20x what the OEM ecu logs, so my numbers are higher than they would be at 1hz (10-15 degrees in my experience). Cooling is absolutely dialed - this was in 93 degree temps with 80

 

[dragoon]

Data is your friend !!

 

[Dave_W]

Love the exhaust and shifting sounds. The fact that Tilton is working with you on the brake balance issues speaks volumes on their customer service and orientation to support racers rather than just churning out parts. And if you ever do a 24-hour enduro, now you know you do need to change pads partway through.

Are you using springs to hold the slip joints together like this?


TiCon makes kits with Ti wire tabs & SS springs.

Titanium Exhaust Hook and Tension Spring for Slip Connector

Ticon Industries Titanium Weld Tab and Tension Spring Kit are perfect for securing your Titanium slip fit joint connectors on your motorcycle or racing exhaust. Designed specifically for racing environments our Titanium weld tabs are CNC bent from high quality 3mm/ .12" thick CP1 Grade Titanium...

www.ticonindustries.com

 

[honeybadger]

Spent a good chunk of my evenings this week working on the replacement Ti exhaust. I don't any full length images right now to share, but here are some pics of my welding progress. definitely getting better

this is the mid pipe connecting to the stainless steel headers/collector





Here's part of the x pipe - the top is one of the most recent joints I welded (last night) and the bottom is a joint a I welded on v1 of this exhaust (probably the 5 or 6th Ti joint I ever welded). Definitely making progress

 

[honeybadger]

Love the exhaust and shifting sounds. The fact that Tilton is working with you on the brake balance issues speaks volumes on their customer service and orientation to support racers rather than just churning out parts. And if you ever do a 24-hour enduro, now you know you do need to change pads partway through.

Are you using springs to hold the slip joints together like this?
View attachment 98481

TiCon makes kits with Ti wire tabs & SS springs.

Titanium Exhaust Hook and Tension Spring for Slip Connector

Ticon Industries Titanium Weld Tab and Tension Spring Kit are perfect for securing your Titanium slip fit joint connectors on your motorcycle or racing exhaust. Designed specifically for racing environments our Titanium weld tabs are CNC bent from high quality 3mm/ .12" thick CP1 Grade Titanium...

www.ticonindustries.com

I didn't on the previous version - honestly not sure it would have been enough to help. There was so much stress on the joints that it bent stuff. This time I'm focusing the supports on the mufflers directly (which is what I should have done to begin with). I did buy a set of springs for the slip joints this time, tho

 

[Fabman]

Spent a good chunk of my evenings this week working on the replacement Ti exhaust. I don't any full length images right now to share, but here are some pics of my welding progress. definitely getting better

this is the mid pipe connecting to the stainless steel headers/collector

View attachment 98515
View attachment 98514


Here's part of the x pipe - the top is one of the most recent joints I welded (last night) and the bottom is a joint a I welded on v1 of this exhaust (probably the 5 or 6th Ti joint I ever welded). Definitely making progress

View attachment 98516

MUCH better….titanium is very difficult to do well and what I see here is very good.

 

[honeybadger]

Ran out of mental bandwidth to update before the event, so next few posts will be out of order. But getting back from a mostly successful weekend at COTA. Was able to squeeze in 6 sessions. Last two were amazing. The very last one was only me and one other car on track. Pretty wild to basically have a facility like COTA to yourself!

Set a new PB of 2:19.8 - still a lot more time on the table. My theoretical best was a 2:17.xx. We got traction working (witch craft I tell you). More on that later. I finally got my brake bias worked out, but I need to go up a size in the cylinders to reduce pedal travel and increase stiffness.

Now that I am finally pushing the car a bit harder, a new symptom has shown up - it's pretty snap on low speed turn in. The front end is extremely sharp and the previous of the car had a very numb front end - so it might be my driving. But I'm thinking I should adjust the rear end to try and help. Thoughts?

Anyways - enough rambling. Here's a few 2:20.xx laps all strung together.

 

[KazarS197]

Ran out of mental bandwidth to update before the event, so next few posts will be out of order. But getting back from a mostly successful weekend at COTA. Was able to squeeze in 6 sessions. Last two were amazing. The very last one was only me and one other car on track. Pretty wild to basically have a facility like COTA to yourself!

Set a new PB of 2:19.8 - still a lot more time on the table. My theoretical best was a 2:17.xx. We got traction working (witch craft I tell you). More on that later. I finally got my brake bias worked out, but I need to go up a size in the cylinders to reduce pedal travel and increase stiffness.

Now that I am finally pushing the car a bit harder, a new symptom has shown up - it's pretty snap on low speed turn in. The front end is extremely sharp and the previous of the car had a very numb front end - so it might be my driving. But I'm thinking I should adjust the rear end to try and help. Thoughts?

Anyways - enough rambling. Here's a few 2:20.xx laps all strung together.

Truly a magnificent build! I love the last open session on a Sunday! After a full weekend I'll skip or short the next to last session just so I can be on the track basically by myself.

 

[ArizonaBOSS]

Now that I am finally pushing the car a bit harder, a new symptom has shown up - it's pretty snap on low speed turn in. The front end is extremely sharp and the previous of the car had a very numb front end - so it might be my driving. But I'm thinking I should adjust the rear end to try and help. Thoughts?

My $0.02:

Technique:
Assuming you are saying "low speed" like T1, 11, and 12 at COTA, those are all slow turns after high speed straights. It's easy to try and go deep on these and not scrub enough speed before turn-in. You could look at your data trace and see if you need to slow down slightly earlier to reduce trail-braking or allow you some maintenance throttle.

Setup:
Soften your rear bar and/or stiffen front bar (depends how that might play out elsewhere in faster parts of the track)
Increase front low speed compression damping and/or rear low speed rebound to keep the car from pitching as much in that situation.
Lower the rear of the car

 

[Dave_W]

No personal experience with aero, but my theory is that you want to get your low-speed handling where you want it first using your mechanical grip tuning knobs, and then fix any high-speed balance issues with your aero knobs. If you like your high-speed handling now, it might intially be one step back but eventually two steps forward.

 

[honeybadger]

My $0.02:

Technique:
Assuming you are saying "low speed" like T1, 11, and 12 at COTA, those are all slow turns after high speed straights. It's easy to try and go deep on these and not scrub enough speed before turn-in. You could look at your data trace and see if you need to slow down slightly earlier to reduce trail-braking or allow you some maintenance throttle.

I have a feeling this is at least part of it. While I got the brake bias figured out, the size of the cylinders meant I was short the last 200 PSI I needed to really lockup the fronts. I looked at the video and noticed on the corners I overrotated, I wasn't engaging ABS. I typically blew through one brake zone hard at least once per session - and none of those triggered ABS either. So I clearly was struggling to get to threshold and I was probably carrying 2-3 mph too much speed. Will take a deep dive at the data this upcoming weekend.

 

[honeybadger]

No personal experience with aero, but my theory is that you want to get your low-speed handling where you want it first using your mechanical grip tuning knobs, and then fix any high-speed balance issues with your aero knobs. If you like your high-speed handling now, it might intially be one step back but eventually two steps forward.

fortunately it's just this low speed turn in that I am struggling with. For the first time in this car's life, I am happy with its mechanical grip at the limit. It's super predictable and easy to work with. I think if I fix the low speed turn in and get the brake pressure issues dialed in, I'll have a rocket ship.

But agree with your statement. COTA is a great testament to this - none of these gremlins showed up at Road America or VIR - they just don't have the same low speed corners. COTA really tests your chassis balance overall

 

[honeybadger]

Some pics from last weekend

 

[JAJ]

I have a feeling this is at least part of it. While I got the brake bias figured out, the size of the cylinders meant I was short the last 200 PSI I needed to really lockup the fronts. I looked at the video and noticed on the corners I overrotated, I wasn't engaging ABS. I typically blew through one brake zone hard at least once per session - and none of those triggered ABS either. So I clearly was struggling to get to threshold and I was probably carrying 2-3 mph too much speed. Will take a deep dive at the data this upcoming weekend.

If the balance is good on the braking system, and you're short of pressure, a higher mu pads might be worth a try. Carbone Lorraine sintered pads have a mu of 0.60, which is quite high and might get your ABS working. I've run sintered pads on my CCB brakes and they're magic - flat torque curve, strong bite and easy to work with. A bit noisy, but what isn't? CL-brakes is the company set up to sell their pads and they make them for most racing calipers.

 

[Tonymustang302]

::::cough:::: paddles :::Cough::::

 

[navseng]

I have a feeling this is at least part of it. While I got the brake bias figured out, the size of the cylinders meant I was short the last 200 PSI I needed to really lockup the fronts. I looked at the video and noticed on the corners I overrotated, I wasn't engaging ABS. I typically blew through one brake zone hard at least once per session - and none of those triggered ABS either. So I clearly was struggling to get to threshold and I was probably carrying 2-3 mph too much speed. Will take a deep dive at the data this upcoming weekend.

going through the brake pressure issue myself.. what size masters are you using? what sort of line pressure are we talking

 

[honeybadger]

If the balance is good on the braking system, and you're short of pressure, a higher mu pads might be worth a try. Carbone Lorraine sintered pads have a mu of 0.60, which is quite high and might get your ABS working. I've run sintered pads on my CCB brakes and they're magic - flat torque curve, strong bite and easy to work with. A bit noisy, but what isn't? CL-brakes is the company set up to sell their pads and they make them for most racing calipers.

I'm fairly certain in my case its the master cylinder size. There's a long joutney I plan to share at some point, but the short version is Tilton originally recommend I use 13/16 size masters front and rear. The result was way too much rear brake bias (45% front, 55% rear) and I was running out of the adjuster threads to try and get it where it should be. So I swapped in a smaller master I had to see if the brake bias would be fixed (I ran a .7 front and .8125 last track weekend) and the bias was finally in the ballbark, but I was running out of the pedal (bottoming it out under heavy braking). Tilton warned me that too small of a front diameter could cause problems because it simply wouldn't push enough fluid into the calipers to do the job (even tho the pressures would be higher).

So I have a new pair coming - one larger for each (.75 front, .835 rear) which should keep the bias the same but make the pedal stiffer. WE'll see.

I am running Ferodo DS3.12s, which have a fairly high mu and a flat torque curve. but we'll see once I get the masters worked out. might need to switch

going through the brake pressure issue myself.. what size masters are you using? what sort of line pressure are we talking

I was running .7 and .812 at COTA last weekend. Pressure peaked at a reasonable spot (1350 psi fronts), but it fell off even though I had the pedal all the way to end of its travel. If we compare a lap where i made the brake zone and one where I didn't, we can see front pressure is dropping off and not quite as high - I can assure you that pedal physically wouldn't move any further no matter how hard you pushed it. My theory is the pressure is peaking and then starts to drop as the pistons move and I run out of pedal to keep the pressures up (i.e. I can't push enough fluid in the caliper at the pressure needed for how far the pistons are moving).