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SN95 LS3 Pony Build Thread Profile - SN95 Mustangs

458
420
Exp. Type
Autocross
Exp. Level
10-20 Years
Kansas City, Missouri
I dropped the driveshaft off today to get checked out. They said they would get to it possibly this evening or in the morning and give me a call. If I can get that taken care of then I'll see if I can get the car on the dyno this week or next and try to make it out to the Kansas City Region double header the weekend off the 1st. It would be my first event in over a year... :oops:

Keep your fingers crossed everybody!
 
458
420
Exp. Type
Autocross
Exp. Level
10-20 Years
Kansas City, Missouri
I picked up the driveshaft and they said it really wasn't out of balance and had no runout. I guess that's good but now I get to start playing with pinion angle again. I also ordered one of the Holley transmission crossmembers that bolts into the factory location. The crossmember I'm running now ties into the subframe connectors so I'm just trying to eliminate that as another possible issue. I'm going to put the car on jack stands in the morning and run it without wheels to see if I can figure anything out.
 
458
420
Exp. Type
Autocross
Exp. Level
10-20 Years
Kansas City, Missouri
Still have a vibration. I made a new thread with more details. Going to pull the rearend apart and start inspecting bearings and axles.
 
458
420
Exp. Type
Autocross
Exp. Level
10-20 Years
Kansas City, Missouri
So, a couple updates.

I tore down the rearend to start checking things out and try to find a possible cause for this vibration. I really didn't find anything concrete to point to but I did find a couple irregularities. All the bearings looked great so I don't think there is any issue there. I found a couple chips out of the edges of the ring gear and pinion gear. It doesn't seem like much but might cause an issue when the two bad spots meet. Doing the math the gears would line up at the same position every 11 revolutions which would point to my slower-than-wheelspeed vibration.

These are pictures of the chipping, doesn't seem that severe but the gears have less than 1000 miles on them.
IMG_2550.JPG
IMG_2554.JPG



I had a set of factory 3.27's so I decided to swap them in. I will be able to do 85mph in second gear but I'll have to swap to something else later. While I was setting up the backlash on the new gears it seemed like the carrier shims were not fitting as tightly as they should so I started swapping out shims for ones a few thousandths bigger until I got it fitting nice and snug. I was able to get about .020" more shims in it than it had before which blows my mind because I remember them being a real pain to get in last time. This could be another possible source of my problem.
IMG_2564.JPG
IMG_2563.JPG


Here's where it's at now;
-Pinion drag - 20in.lb
-Backlash - .009"
-Carrier Runout - .001"
-Carrier side to side movement <.001"

Here's the mesh pattern with the new gears.
IMG_2567.JPG
IMG_2568.JPG

My lastest issue is the axle spacer cover retaining ring was destroyed trying to take it out so I'm now trying to find a replacement snap ring which is proving to be more difficult than I ever expected. Eaton sells a kit with the snap ring, cover, and axle spacer for $62 but I only need the $2 snap ring. I contacted Eaton and they said it's 2.420" resting diameter. I've been to Oreilly's, Autozone, Carquest, Napa, Family Center, Transwest, Golden Valley Tractor, Fastenal, Gears Unlimited, Tractor Supply, and called Summit Racing. Nobody has this damn snap ring. I ordered the closest I could find from McMaster-Carr and hoping it will work but the car is dead on the lift until it gets here. If I can get the vibration figured out I'm scheduled for some dyno time on August 19th at Knight Performance to retune for the new camshaft.
Inkeddtl-52736_xl_LI.jpg
 
458
420
Exp. Type
Autocross
Exp. Level
10-20 Years
Kansas City, Missouri
Updates:

I finally finished the fire suppression installation. I made a mount to fit in the unused vent hole on the dash. This should be easy to reach for the driver or a corner worker if needed. I got decals on the way. The kit did not come with near enough tubing to get the nozzles where I wanted them so I had to order another roll.
IMG_2589.JPG
IMG_2590.JPG

I have one nozzle pointed toward the battery in the trunk, one nozzle pointed at the driver, and I put the last 360 degree nozzle right over the top of the engine.
IMG_2592.JPG

Here's where I mounted the pull cable.
IMG_2608.JPG
IMG_2610.JPG
 
458
420
Exp. Type
Autocross
Exp. Level
10-20 Years
Kansas City, Missouri
I also replaced the harmonic damper. I was looking into a rebuild of my ATI damper and while reading the literature on it I noticed something. There are 6 bolts that hold the damper together and another 3 bolts for adding another pulley if needed. The instructions say all 9 bolts must be used even if no pulley is added or DAMPER DAMAGE WILL OCCUR!! in big bold letters. My damper has never had all 9 bolts since it's been on the car. It was given to me originally and I assumed it was good so just installed it. I bought a SFI approved Summit Racing brand damper and swapped it out. It was totally worth it. The engine has never run smoother. I ran it up to 120mph on my private road and it feels great. I may still look into having the ATI damper rebuilt but I see no reason to not run the Summit damper. I'm really looking forward to some dyno time later this week and autocross next weekend with Kansas City Region.
IMG_2600.JPG
IMG_2618.JPG
IMG_2619.JPG
 
458
420
Exp. Type
Autocross
Exp. Level
10-20 Years
Kansas City, Missouri
We made it to the dyno this morning and got the tune finished up for the new cam. It didn't exactly go how I expected but I'm not complaining. I think the last cam was just really mismatched for my combination. It put down 500hp/477tq on 93 octane. Over 400ft.lbs from 3500 all the way to 6500. Now autocross on Saturday after almost 2 years away.
IMG_2631.JPG

 
458
420
Exp. Type
Autocross
Exp. Level
10-20 Years
Kansas City, Missouri
Nice build. What I'd like to know is, why did you delete the ABS and how are you liking the car without it?
I don't think I would have been able to keep the ABS without keeping the stock ECU in the car but I could be wrong. I also wanted to get rid of the monstrosity of brake lines in the engine bay. I like the car just fine without it.
 
458
420
Exp. Type
Autocross
Exp. Level
10-20 Years
Kansas City, Missouri
Wow 500 on a mustang dyno is a solid number.

So did you figure out what the cause of that vibration was?
Between rebuilding the rearend and changing the damper it got rid of all of it. I think my ATI damper was actually damaged so I'll probably rebuild it and hold onto it.
 
4,325
3,897
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
I don't think I would have been able to keep the ABS without keeping the stock ECU in the car but I could be wrong. I also wanted to get rid of the monstrosity of brake lines in the engine bay. I like the car just fine without it.
Yeah, same problem here, I still have the ABS but it doesn't talk to the new computer and doesn't work at all...I keep threatening to delete it but also holding onto the dream that somebody can fix it...so far, no one has. :(
 
458
420
Exp. Type
Autocross
Exp. Level
10-20 Years
Kansas City, Missouri
First time towing with the new truck.
IMG_2638.JPG

My first autocross since 2019 went pretty smooth. I won a small CAM-T class but my time was also good enough for 2nd in CAM-C. The car did great. I even went for about a 2 hour drive today with my daughter. None of my equipment worked yesterday so I don't have any video and my GPS wasn't synced with my phone for some reason so the data is really choppy. Front grip is a real issue. I just can't carry much speed through the corners without pushing and I'm running so much camber that I'm locking up the wheels under braking. Next time I'm going to take a little bit of camber out to try to help braking but otherwise I'm not sure what the real solution is.
IMG_2643.JPG

IMG_2644.jpg


IMG_2645.jpg
 
458
420
Exp. Type
Autocross
Exp. Level
10-20 Years
Kansas City, Missouri
After talking to Jack at Maximum Motorsports he recommended I go up to a bigger diameter rear sway bar to move more of my weight transfer to the rear of the car and get rid of the understeer.
I currently have the 1" x .120" and he suggested the 1.25" x .125".

Mr. Stump,

Assuming that the current rear swaybar on your car is set to full stiff, the front roll stiffness percentage is now 74.8%. With the rear swaybar on full soft, it is now 76.2%. With the Steeda front swaybar, OEM 1” rear swaybar and original rear springs, it was previously 73.2%. The car understeers worse than before, but it has less overall body roll. There is far too much weight transfer between the front tires in corners. This will always result in a lot of understeer. You need to have a larger percentage of the weight transfer during cornering, to happen across the rear tires.

The spring rates on the car look perfect for the weight distribution, so the easiest way to increase weight transfer across the rear axle, while keeping the body roll low is to use a stiffer rear swaybar. If you change the rear swaybar to the MMRSB-9.1 model, on full soft the front roll stiffness percentage will be 71% and on full stiff it will be 68%. To convert your existing rear swaybar to this model, you need to purchase the MMRSB-95 and SB-012. This will make the car vastly faster to drive, as you won’t be waiting, waiting, waiting to be able to get on the throttle until after the corner ends.

Let me know how this works.

Sincerely,
Jack Hidley
Maximum Motorsports Tech Support
rear_swaybar_rate_chart.jpg
 
Last edited:
458
420
Exp. Type
Autocross
Exp. Level
10-20 Years
Kansas City, Missouri
I had the car on the scales yesterday and noticed my corner weights were off since changing the transmission and all the other work I've done since I last corner weighted it. So today I took some time to get it set back up correctly.

Here's where it ended up with me in the car and a full tank of gas.
IMG_2672.JPG

I used this calculator. https://robrobinette.com/corner_weight_calc.htm
corner weight.JPG

I also used this as an opportunity to swap out my sway bar end links for my newest version. The old ones were steel, these are 6061 aluminum. I had a batch made about a year ago and never remember to put a set on.
IMG_2673.JPG
 

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