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MotoIQ - Project Budget 400whp S197 Mustang Track Car

Grant 302

basic and well known psychic
Wouldn't the Ford Performance Jounce bumpers be an improvement over the stock ones?


pretty sure they are. But IIRC, the advice was along the lines of, “…take those off and throw them away…” at least in the context of the rear ones.
 
Hey @BillyJRacing, got a question about cutting the front bumpstops. I know it's free and easy, and those are big plusses. But looking at the pics, the portion you removed seems to have a large inner diameter to provide an initial "cushion" on contact and a rising rate as the bumpstop is compressed. By using only the bottom half, you're moving the engagement point further into the bump travel, but it seems the rate will be much higher when contacted. So if/when the bump travel gets into the bumpstop, the wheel rate will increase more sharply from bumpstop contact to bump limit, providing a harsher ride.

I'd think that a better solution would be a bumpstop that might be a bit shorter than stock but still provides a smooth transition of rate through the range of bump travel in which it's engaged. Bumpstops are generally under $20 each, so they are a small cost in a suspension package costing over $1K.

I suppose the engineering method woud be to compare the bump and roll resistance for the stock and Steeda suspension setups, especially for the lateral g load you're expecting to acheive. From that, it could be that the stiffer springs and sway bar end up meaning you're not into the bumpstop as much on the Steeda setup. And if you do get into the bumpstop, the rate of increased bump/roll stiffness contributed by the bumpstop is a smaller percentage of the overall rate as compared to the stock suspension, yielding a less "crashy" ride approaching the bump travel limit.

RE Suspension publishes Travel Sheets and Graphs for Speedthane, Ohlins, Penske, and their own bumpstops on their Tech Info page.
https://www.resuspension.com/tech-info
For this suspension and most Mustang Coilovers, you should not engage the bumpstops in pitch or roll - only over heavy vertical G loads and bumps.
 

Norm Peterson

Corner Barstool Sitter
939
709
Exp. Type
HPDE
Exp. Level
5-10 Years
a few miles east of Philly
For this suspension and most Mustang Coilovers, you should not engage the bumpstops in pitch or roll - only over heavy vertical G loads and bumps.
Agreed - but why not re-introduce a little compliance over the initial ranges of bump stop contact?

This would be mostly for dual-purpose cars that could see combinations of bumps with the car loaded with more than just the driver and possibly a right-seat passenger.

Grinding the hole into a cone shape ought to restore some initial compliance. Even the flat surface got a mild cone rework.

Side note: I only cut off half a convolution because I initially lowered the rear suspension by only about 15mm with 220 lb/in springs. Which has since been raised back up to only about a 6mm drop for reasons unrelated to bump stop contact.

full.jpg


Norm
 
Hey guys,

Part 8 is now live:

Project Budget 400WHP S197 Mustang Track Car: Part 8 – Aero with Steeda and Ford


" For the S197 Mustang platform, proven aero does not have to be expensive. We install a wind tunnel-tested Steeda wing and a BOSS 302 splitter to improve the downforce of our car."

h%20Boss%20302%20Splitter%20and%20Steeda%20Wing-X2.jpg


In the article:
-Remove factory decklid spoiler
-Install Steeda wing
-Install BOSS 302 splitter and undertray


-Billy
 

APEXRaceParts

Race Proven, Street Approved
Supporting Vendor
622
888
Exp. Type
Time Attack
Exp. Level
5-10 Years
Bay Area, CA
I ran that wing on my 3v years ago and really liked it. Wish I would've kept it and ran on the 2011 instead of the APR wing to be honest, that car was never balanced even with the 302S front splitter.

Good progress so far!
 

xr7

TMO Addict?
439
448
Exp. Type
Autocross
Exp. Level
5-10 Years
Minnesota
Billy, do you have the part# for this wing? I did not see this wing on Steeda's website.
 
2
1
Exp. Type
HPDE
Exp. Level
Under 3 Years
San Diego
Hey guys,

I just started a new project on MotoIQ, taking my experience and background racing the S197 Mustang platform professionally over the past 10 years in Grand-Am to recommend how to make an inexpensive, powerful, great handling and fun to drive track car. Stay tuned for some insight on the car, what's important to upgrade and what isn't necessary or even detremental to change. Enjoy:

"More people need to consider the (2005-2014) “S197” Mustang for track use! Parts are cheap and it really does not take much to turn one into an awesome “Driver’s-car”. There are a lot of misconceptions that Mustangs don’t handle well, are too heavy, and only belong on the drag strip. This project car is focused on dispelling these myths and show how to make arguably the best and least expensive 400whp track car."

View attachment 58020


-Billy
 
108
77
Billy or anyone, I'm not trying to pin down exact numbers or anything but can you give an estimate of the change these mods might be expected to make, front and rear, in terms of pounds of downforce? Or pounds of reduced lift? Say at 80 or 100 mph? I'm just trying to roughly quantify the ballpark expected change.

My car looks like the before picture. I saw reference in the article to hundreds of pounds of downforce in the rear? At what speed?

Many thanks, I've really enjoyed and learned from following this project car - it looks great.
 
Billy, do you have the part# for this wing? I did not see this wing on Steeda's website.


That's the wing, general lead time was 15 weeks when I inquired.
 

xr7

TMO Addict?
439
448
Exp. Type
Autocross
Exp. Level
5-10 Years
Minnesota

That's the wing, general lead time was 15 weeks when I inquired.
I'm not sure that is the wing Billy used. In the photos it doesn't look "bent" like this one and his wing is for the 05-09 body style. That's the reason for the 3D printed "adapters" that are referenced in the article. The shape of the trunk lid is different on the '10-14's vs the '05-09's.
'
 
I'm not sure that is the wing Billy used. In the photos it doesn't look "bent" like this one and his wing is for the 05-09 body style. That's the reason for the 3D printed "adapters" that are referenced in the article. The shape of the trunk lid is different on the '10-14's vs the '05-09's.
'

Hopefully he will chime in then, wouldn't mind having the exact wing myself.
 
1,148
933
Exp. Type
HPDE
Exp. Level
5-10 Years
Philly Metro Area
Correction: probably the street version 307-0010
 
4,447
4,231
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
You still have significantly less compression travel than you would have with a shorter (my soon to be in the market) bump stop. You're likely hitting that stop more than you think and hurting rear grip in many normal, let alone aggressive driving conditions.
I'd love to hear your thoughts on bump stops.
It seems there are two schools of thought:

1) Don't let your car hit the stops because it becomes a spring of infinite stiffness (or rapidly rising rate)
2) Use the bump stops to pin the car down, use packers to get the height where you want it and let it sit on them in the corners.

Personally, when ever I go to a new track or re spring the car I always put a go pro on my coilovers to insure that they only contact momentarily in extreme bump but stay off them 99.9% of the time.

However, I've seen some very fast cars use both methods successfully.
What are your thoughts...especially since it sounds like you are about to release something to address this.
 
Correction: probably the street version 307-0010
Definitely. Thanks for the great articles, Billy! Any chance you can whip-up some of those 3-D adapters for use with the Steeda wing? I have called around to a lot of the race teams hoping they had a pair in a box somewhere in the back of the shop, but no such luck. Unobtainium. I would be happy to pay for a set for the Steeda wing that has been sitting in my garage for 7 or 8 years. One thing I noticed was that on your race car, they mounted that wing as far back as it would go. Is that still the way to go?

DSC_0079.jpg

DSC_0090.JPG

DSC_0092.jpg
 
Correction: probably the street version 307-0010
That's the correct one.
I'd love to hear your thoughts on bump stops.
It seems there are two schools of thought:

1) Don't let your car hit the stops because it becomes a spring of infinite stiffness (or rapidly rising rate)
2) Use the bump stops to pin the car down, use packers to get the height where you want it and let it sit on them in the corners.

Personally, when ever I go to a new track or re spring the car I always put a go pro on my coilovers to insure that they only contact momentarily in extreme bump but stay off them 99.9% of the time.

However, I've seen some very fast cars use both methods successfully.
What are your thoughts...especially since it sounds like you are about to release something to address this.
You can set a car up 100 different ways and make it fast. But different setups on different cars for different conditions/tires/types of racing/etc... will all have strengths and weaknesses. For this project, people who want to not have a daily driver that will beat them up, and for most people who track S197's, it's best to have the car stay out of the bump stops in most conditions short of large vertical loading and bumps. Hopefully the shortened rear bumpstops I designed will be ready soon and I can make an article on those -which EVERY S197 Mustang should have installed on the car.
Definitely. Thanks for the great articles, Billy! Any chance you can whip-up some of those 3-D adapters for use with the Steeda wing? I have called around to a lot of the race teams hoping they had a pair in a box somewhere in the back of the shop, but no such luck. Unobtainium. I would be happy to pay for a set for the Steeda wing that has been sitting in my garage for 7 or 8 years. One thing I noticed was that on your race car, they mounted that wing as far back as it would go. Is that still the way to go?
I'm glad to hear you are enjoying them. I could print some more adapters. Shoot me a DM. Yes, ideally you'd mount the wing as far back as you can, but the difference from where we had it in the race cars and where I mounted it in the project car isn't significant.
 

Dave_W

Cones - not just for ice cream
418
404
Exp. Type
Autocross
Exp. Level
20+ Years
Connecticut
for the Steeda wing that has been sitting in my garage for 7 or 8 years.
Have you thought about starting with some aluminum bar stock, and using a grinder or mill file to create the taper? Maybe get an idea of the shape you need with clay or wood mockup before going to metal.

Never mind, Billy just beat me to the post.
 

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