Howitzer's Long Term Street to Track 2015 Mustang GT Build

[Renatus]

Ooh awesome! Sorry i’m new in this forum. Thank you

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[Renatus]

Btw I’m looking for N/A powered

 

[HKusp]

Btw I’m looking for N/A powered

Here's the best place to start. Happy reading.

https://www.mustang6g.com/forums/forums/v8-5-0l-engine-mods-bolt-ons-exhaust-tuning.62/

 

[Howitzer]

BTW, I just realized I have MM Camber plates, NOT MMR. Not sure if that makes a difference, these are what I have, but not installed yet: https://www.americanmuscle.com/mm-caster-camber-plates-2015.html

Ah! yes, that will make a difference. Looks like the MM Camber plates re-use the rubber top mount. So they shouldn't chatter.

 

[Biggsy]

I got Apex 25mm spacers to use. And yes, extended studs. They are the ARP studs that came with the ford performance wheel hubs. These are 3" from the hub face (3.5" overall i believe).

These spacers have small notches on the bottom to help with getting them off if they get stuck. I wanted some that had that since I'd be changing often. OPMustang also makes some very similar. I just got the new setup within the past month so haven't had a chance to test it all, just tested fitment. The spacers shouldn't be a pain at all, they just slide on/off.

Spacers:

New Hubs w/ Extended Studs:

New Wheel Set for Track - SVE R350 19x11 wrapped in Kumho V730 305/30

Curious on your thoughts. I love them so far. Just not in wet/damp conditions

 

[Howitzer]

Curious on your thoughts. I love them so far. Just not in wet/damp conditions

Hopefully I can gather an opinion soon. I was going to use them over memorial day weekend at VIR but it was calling for a very wet weekend, so I didn't want to chance them in rain. I don't have other 200tw tire experiences though - this will be the first. I've been running on 340tw Firestone Indy 500 tires which...have honestly surprised me in their capability and longevity. Excited to see what I can do with a stickier(and wider) tire though.

 

[Biggsy]

Hopefully I can gather an opinion soon. I was going to use them over memorial day weekend at VIR but it was calling for a very wet weekend, so I didn't want to chance them in rain. I don't have other 200tw tire experiences though - this will be the first. I've been running on 340tw Firestone Indy 500 tires which...have honestly surprised me in their capability and longevity. Excited to see what I can do with a sticker(and wider) tire though.

Smart move. I went out a morning after serious rain last month at Summit Point and it was very sketchy. Fortunately it dried up as the day went on. I’m sure you have read up on it but they like low pressures. I go out on 23 cold to bring it up to 31/32 hot.

I hope to hit VIR later this year

 

[Howitzer]

Smart move. I went out a morning after serious rain last month at Summit Point and it was very sketchy. Fortunately it dried up as the day went on. I’m sure you have read up on it but they like low pressures. I go out on 23 cold to bring it up to 31/32 hot.

I hope to hit VIR later this year

Rock on! Hit me up if you may make it out there later in the year. I'll probably be back in a couple months.

I always welcome any tips. Most of what I know of the Kumhos are from a buddy with an almost total opposite car so things don't exactly translate 1:1.

 

[Howitzer]

Speaking of VIR...

As I mentioned, was able to get out over Memorial Day weekend at VIR. It was a rainy weekend so I decided not to test out the new shoes. Overall a good time, though I did see the most cars going off track and crashes I've ever seen in one day. I'm sure some due to the weather. Rain was not heavy at all and really not even enough to saturate the track on Saturday though. 2 cars ended up crashing...both mustangs...which made me quite sad. One was a new GT500 (no idea if he's on here, never seen the car before) in I think novice group and a highly modified new edge that I believe was an instructor.

No incidents from myself. I don't think I'm very fast but it's always a good time when the guy with the Porsche 911 Carrera S comes up to you to say how much fun he had trying to keep up.

Pic from the event, my lovely wife keeping warm in the passenger seat. She's been with me to every event so far.

 

[Howitzer]

Brake Cooling
This was done back in September of 2022 but it was an interesting upgrade on the non-PP car, so wanted to outline it here.

The first thing I did just before I started tracking this car, was upgrade to the Brembo brake calipers and was running with Hawk 5.0 pads on OEM blanks.

After a hot summer last year, I was measuring brake temps with an infrared thermometer. I noticed temps fairly high. In the paddock, after a cooldown lap. I was seeing over 750°F. I figured I was starting to exceed temps of the brake pads. So, two things, I was looking to upgrade brake pads and I'd add some cooling to help keep things happy.

Having the base car, I had no air deflectors on the control arms and the rock guard/belly pan had no channels for directing air flow. In fact, it seems to actively prohibit most air from going to the brakes with the large rubber strip it has.

Parts list:

• OEM Performance Pack rock guard
• OEM Performance Pack front splitter
• Vorslhag air deflectors

Original Base rock guard (and splitter):

New PP rock guard and splitter:

Showing the air channels towards the brakes a bit better:

For this to fit right, the existing wheel liners also had to be trimmed to fit the air channels in the new rock guard. Fairly simple - did some rough measuring and cut with dremel. Looking at it now, you wouldn't even be able to tell it wasn't made for it. Added push pins like OEM to secure the liner to the new guard.

Cutting liners: Did the same on both sides and drilled holes for the push pins.

Showing rock guard installed:

Everything installed (including the Vorslhag air deflectors):

So the question...did this make a difference? Absolutely! I seem to be about 100-150°F lower when measuring at the same tracks than where I was before.

I also love the look of the PP splitter much more than the base - I've changed up the front end a lot in the past couple months as well, so I'll show that in another post soon.

 

[Howitzer]

Differential and Driveshaft Swap
Plus fresh axle seals, race bearings and fixing a cracked diff bushing!

Completed this end of February of 2023, but thought I'd share as it was a fairly involved project. I’m a bit behind on a few things.

Parts:

• 3.55 Torsen Differential from 2021 donor car - Code S273F (w/ 12k miles)
• Driveshaft from 2021 donor car (w/ 11k miles) (those poor cars)
• New driveshaft to pinion bolts (part #FR3Z-4B496-B)
• New axle seals and race bearings for the new diff (part #M-4413-B)
• Steeda alignment dowels
• BMR Differential hardware upgrade kit (BMR-RH017)
• New diff fluid (BG Ultra-Guard 75w-140)
• Whiteline KDT934

I’m not going to make this a how-to, but for anyone curious – yes, the 18+ differentials when coupled with the driveshaft is a direct fit in the 15-17s (you could always swap the pinion flange in the diff instead of getting the driveshaft but that seemed like more of a PITA). The manual and automatic driveshafts are still different due to the transmission connection but there is no longer a difference at the pinion.

This was a fun one to do on jack stands in the garage. It honestly wasn’t THAT bad. I did have to get a little scissor transmission jack to do this. Fairly simple all things considered – the new parts all bolted up properly without additional modifications.

The main reason I wanted to do this was so I wouldn’t wear out the clutch packs and be left with an open diff with the Traction-Lok diff.

During the project, I did find a badly cracked driver side diff bushing in the subframe. I couldn’t find any replacements that I could get in a reasonable time, so I caulked some polyurethane in there (from construction isle in lowes – I hear the “3M Window Weld” is also a good option for this) in the bushing and covered all cracks. Put my Whiteline pucks back in– and so far it’s holding up just fine.

Added the stronger bolts to resist shearing and steeda alignment dowels so the subframe will stay at the same alignment if I have to lower the subframe again.

New and Old side by side:

Axle seal replacement:

Cracked bushing: (the cracks went all the way through the bushing and nearly all the way around).

Fix:

Back together:

 

[Biggsy]

Do you have to drop the subframe to replace the diff? I know you were doing the alignment dowels so you did but for only a diff change, I am curious if it is mandatory.

 

[Howitzer]

Do you have to drop the subframe to replace the diff? I know you were doing the alignment dowels so you did but for only a diff change, I am curious if it is mandatory.

If you're using stock bolts, lowering the subframe may not be necessary. There's a chance the rear diff bolts may rub or get stuck at the tire well when taking them out...but I don't remember if that was with the stock bolts or the upgrades. It was definitely easier lowering the subframe though.

If you're using the upgraded bolts or pucks from something like the kits I mentioned when I did mine, lowering it will be necessary. There's no room to get a bolt/puck in from between the diff and fuel tank otherwise.

 

[Howitzer]

I haven't commented on it yet, but I do absolutely love the Kumho Ecsta V730 tires. Significantly more grip and still very communicative. Still learning to use all the grip.

That said, with the new grip levels...I finally hit the threshold where oil can get sloshed up into the driver side PCV. Luckily I did have a driver side catch can already installed in preparation for if I ran into this problem.

Here's a picture after ONE session. It was near full when I caught it during the 3rd session of the day. Thankfully i remembered to check it.

So...next on the list is installing the GT500 valve covers. Already have them in, just need to actually install them.

For anyone curious - this issue only appears to be a problem on the Gen2 engines and is due to not enough baffling in the valve covers.

 

[Biggsy]

I haven't commented on it yet, but I do absolutely love the Kumho Ecsta V730 tires. Significantly more grip and still very communicative. Still learning to use all the grip.

I really wish they came in 18s. I really love the tire myself.

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