The Mustang Forum for Track & Racing Enthusiasts

Taking your Mustang to an open track/HPDE event for the first time? Do you race competitively? This forum is for you! Log in to remove most ads.

  • Welcome to the Ford Mustang forum built for owners of the Mustang GT350, BOSS 302, GT500, and all other S550, S197, SN95, Fox Body and older Mustangs set up for open track days, road racing, and/or autocross. Join our forum, interact with others, share your build, and help us strengthen this community!

Let's Talk Horsepower

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

189
290
Exp. Type
Time Attack
Exp. Level
10-20 Years
75024
Those lighter wheels and girodiscs would win in both handling, acceleration, and rotating mass. I would asterisk those. Expensive but do fit the buy once and done.
 
Last edited:

xr7

TMO Addict?
706
821
Exp. Type
Autocross
Exp. Level
10-20 Years
Minnesota
I can see horsepower being an advantage when running on the track. For autocrossing unless the course is very wide open the V6 Mustang with the right mods in CAMC can be very competitive. The class winner this year is a V6 S197, probably the lowest HP car but some good mods and a really good driver.
 
42
26
Exp. Type
HPDE
Exp. Level
5-10 Years
Los Angeles
SMG

Your car is dynotuned? I picked up all the power from the dynotune. I don't have any engine mods, just exhaust work.

Ray at FTK tuned this car. Made the car run cooler and modified the throttle mapping/when CMCV opens. See below for before and after. I am on 91 tune.


Before.JPGAfter.JPG
 
Last edited:
303
371
CA
Some more spreadsheets for us to ponder:

Current power levels, full on gutting for weight reduction, the best I can get for my power to weight ratio is:

0.0906 RWHP/LB


This would cost $9000 to achieve.

Using the excel sheet, I have come up with the cheapest way to hit my target of 0.1 RWHP/LB (hint hint, it involves BIG power):

1670540803354.png

Some food for thought. Looks like no matter what I'll have to open the engine up.

Here is a screenshot which shows the general "bang for your buck" as it relates to power to weight ratio and cost. See the far right column. The green numbers are good, orange is medium and red is bad.

1670541022930.png

Definitely have some thinking to do, I did not realize power mods would be so efficient at increasing the power to weight ratio, but in hindsight it makes perfect sense given rwhp is a much smaller number than curb weight :ohdamn::ohdamn::ohdamn:
 

Mad Hatter

Gotta go Faster
5,237
4,227
Santiago, Chile
Some more spreadsheets for us to ponder:

Current power levels, full on gutting for weight reduction, the best I can get for my power to weight ratio is:

0.0906 RWHP/LB


This would cost $9000 to achieve.

Using the excel sheet, I have come up with the cheapest way to hit my target of 0.1 RWHP/LB (hint hint, it involves BIG power):

View attachment 81811

Some food for thought. Looks like no matter what I'll have to open the engine up.

Here is a screenshot which shows the general "bang for your buck" as it relates to power to weight ratio and cost. See the far right column. The green numbers are good, orange is medium and red is bad.

View attachment 81812

Definitely have some thinking to do, I did not realize power mods would be so efficient at increasing the power to weight ratio, but in hindsight it makes perfect sense given rwhp is a much smaller number than curb weight :ohdamn::ohdamn::ohdamn:
So very true! Getting down to 3000lbs can be really expensive. Maybe that coyote swap is not such a crazy idea??

Out of curiosity, the price of 7000 for heads and cams was including shop work and install?? Because you could get a Gen2 coyote/tranny for about that.
 

Dave_W

Cones - not just for ice cream
984
1,277
Exp. Type
Autocross
Exp. Level
20+ Years
Connecticut
Be careful of the lightweight K-members - they are typically built for drag racing and not robust enough for curb-hopping track cars.

Losing weight not only improves acceleration, but deceleration and turning as well. Not to say power may still be best bang-for-buck, but you need to look at the whole picture.

Another idea is to see if the plateau you've hit is the car or the driver. Sometimes we just get comfortable with the car and our driving style. It's happened to me. See if you can get a hot shoe instructor to take a few laps at the next event as you ride shotgun and see if they can better your lap time. Pay attention to braking point/amount, throttle tip-in, and line through the corners.
 
29
25
Exp. Type
HPDE
Exp. Level
Under 3 Years
SE Virginia
I once read an article about a Lotus or something, and the writer said manufacturers were always adding power because it's so much easier than "adding lightness". 😅


Now that I'm more awake and took a good look at the spreadsheet,
I can see where new wheels wouldn't be a cost-effective improvement over what you've got now, but I'd consider that AGM battery.

Also, let's not forget that our weight issues aren't just about the amount of weight, but also the weight distribution. The carbon fiber hood was a good step. I wouldn't consider a carbon fiber trunk lid at all. Is your current battery in the trunk? If not, maybe it should be.
Come to think of it, once the battery is in the trunk you might not want a weight-saving battery.
 
Last edited:
303
371
CA
So very true! Getting down to 3000lbs can be really expensive. Maybe that coyote swap is not such a crazy idea??

Out of curiosity, the price of 7000 for heads and cams was including shop work and install?? Because you could get a Gen2 coyote/tranny for about that.
Yes, that would be for a "plug and play" set of fully assembled, ported, polished, big cams, and installation cost. It could be less, but I digress.

For the time being, I'm really not interested in a coyote swap. I like keeping the 3v DNA of the car, and based off how well the rest of the car is set up and my driving abilities, I am quite certain an extra 60-80whp is all I will need to put coyote S197's behind my bumper 🤠

Be careful of the lightweight K-members - they are typically built for drag racing and not robust enough for curb-hopping track cars.

Losing weight not only improves acceleration, but deceleration and turning as well. Not to say power may still be best bang-for-buck, but you need to look at the whole picture.

Another idea is to see if the plateau you've hit is the car or the driver. Sometimes we just get comfortable with the car and our driving style. It's happened to me. See if you can get a hot shoe instructor to take a few laps at the next event as you ride shotgun and see if they can better your lap time. Pay attention to braking point/amount, throttle tip-in, and line through the corners.
Yup, I have read this as well, hence the K-member I have on order is cortex, spoke with Filip at length about it and he said it is stiffer than stock.

In regards to plateau, I had an opportunity to let a pro drive my car once, who was familiar with S197, and I was going to do it, but at the last minute, I got nervous that he would crash the car....Definitely have some regrets on that one.

I think as a driver I probably leave about 0.5s on the table compared to an actual professional. I know I leave some time on the table but it definitely isn't much. I try and compare myself to spec mustang cars. They run better aero than me, lighter than me, have more HP than me and run 285 width slicks. Yet, I am only (on average) 3s slower than them on a 2 minute course. All the while I am on slower than average 200tw tires. When you consider all of those factors, and the amount of time each of those will add (slicks alone are 1-3s, better aero another 1s, lighter weight 1s, more power 1s), I think I am near the capabilities of professionals in professionally prepped cars.

Slightly ricer math, but it is a well known quantity that good slicks are easily 2-4s faster than a 200tw. I regularly match times for similarly modded coyote S197's (but with an extra 100rwhp), hence the reason I think I'm pretty decent behind the wheel 🤠.

I once read an article about a Lotus or something, and the writer said manufacturers were always adding power because it's so much easier than "adding lightness". 😅


Now that I'm more awake and took a good look at the spreadsheet,
I can see where new wheels wouldn't be a cost-effective improvement over what you've got now, but I'd consider that AGM battery.

Also, let's not forget that our weight issues aren't just about the amount of weight, but also the weight distribution. The carbon fiber hood was a good step. I wouldn't consider a carbon fiber trunk lid at all. Is your current battery in the trunk? If not, maybe it should be.
Come to think of it, once the battery is in the trunk you might not want a weight-saving battery.
That's a great point in regards to distribution, strictly from an acceleration standpoint, do you think distribution would matter?
 

JDee

Ancient Racer
1,797
2,001
Exp. Type
W2W Racing
Exp. Level
20+ Years
5 miles from Mosport
That battery in the trunk thing. I did the math on it and with the added weight of cable it didn't seem to me to be a good thing, you need a full length of cable on the power side and with that length you need more thickness as well to avoid too much voltage drop. That cable weight was going to be significant and while some of that weight was going aft it didn't seem to me to be enough to be worth doing.

So I went with a Braille B2015 in the stock location at about half the weight of the stock battery. But that's a mixed blessing as well, under perfect conditions it will start the car fine, but there are situations where it was very marginal, like when it's hot it often will just go "clunk" and not turn the motor over at all. Got tired of looking for a paddock spot on a slope to bump start the damn thing.

I always worried about a spin on track or an off track with a stall of the engine and then the battery refusing to start a hot motor. While it never happened, I just did not want to be that guy that caused a stoppage of a session to remove my car.

I've just gone back to the stock battery in the stock location and lived with it, for me with just a lapping day car, the weight loss did not outweigh the practical need for a reliable starting battery. Race cars, as always, are a different story.
 
29
25
Exp. Type
HPDE
Exp. Level
Under 3 Years
SE Virginia
That's a great point in regards to distribution, strictly from an acceleration standpoint, do you think distribution would matter?
It matters in terms of traction, doesn't it? Am I correct in guessing that was already a concern, since you have that wing?
By my thinking, you should take all the weight you can off the front of the car to improve turn-in, cornering, and whatnot, and leave weight on the drive wheels for the sake of traction.
As you increase power, because that's the more cost-effective way to improve power-to-weight ratio, I expect weight on the rear tires makes difference in how much power you can apply before you exceed your traction.
 
303
371
CA
That battery in the trunk thing. I did the math on it and with the added weight of cable it didn't seem to me to be a good thing, you need a full length of cable on the power side and with that length you need more thickness as well to avoid too much voltage drop. That cable weight was going to be significant and while some of that weight was going aft it didn't seem to me to be enough to be worth doing.

So I went with a Braille B2015 in the stock location at about half the weight of the stock battery. But that's a mixed blessing as well, under perfect conditions it will start the car fine, but there are situations where it was very marginal, like when it's hot it often will just go "clunk" and not turn the motor over at all. Got tired of looking for a paddock spot on a slope to bump start the damn thing.

I always worried about a spin on track or an off track with a stall of the engine and then the battery refusing to start a hot motor. While it never happened, I just did not want to be that guy that caused a stoppage of a session to remove my car.

I've just gone back to the stock battery in the stock location and lived with it, for me with just a lapping day car, the weight loss did not outweigh the practical need for a reliable starting battery. Race cars, as always, are a different story.
Did you ever reach out to Braille about this? The scenario you describe above is definitely one I'm not interested in!
 
303
371
CA
It matters in terms of traction, doesn't it? Am I correct in guessing that was already a concern, since you have that wing?
By my thinking, you should take all the weight you can off the front of the car to improve turn-in, cornering, and whatnot, and leave weight on the drive wheels for the sake of traction.
As you increase power, because that's the more cost-effective way to improve power-to-weight ratio, I expect weight on the rear tires makes difference in how much power you can apply before you exceed your traction.
Yes, that's a great point. As is, the car is balanced pretty well, but does suffer from understeer at speed. I'm hoping putting a splitter on will fix this.
 

JDee

Ancient Racer
1,797
2,001
Exp. Type
W2W Racing
Exp. Level
20+ Years
5 miles from Mosport
Did you ever reach out to Braille about this? The scenario you describe above is definitely one I'm not interested in!
Took it the dealer, they tested it, said it worked within spec. So I think it is just not big enough to crank a hot Coyote reliably. With the stock Ford battery there are no issues, so, since I'm just lapping, I prefer reliable to saving a few pounds.
It has been repurposed into a high tech device for crushing film plastic bags into a small tight package for the recycle man.
 
303
371
CA
Went through two Brailles with out much luck, problems starting and then they died within 3 to 4 months.
Were these lithium Brailles or AGM Brailles?
Took it the dealer, they tested it, said it worked within spec. So I think it is just not big enough to crank a hot Coyote reliably. With the stock Ford battery there are no issues, so, since I'm just lapping, I prefer reliable to saving a few pounds.
It has been repurposed into a high tech device for crushing film plastic bags into a small tight package for the recycle man.
Took it to the dealer as in....Braille dealer? Or ford dealer?

Also, dumb question.... but wouldn't a hot engine be easier to crank over than a cold one? I take it the battery might not work as well if it gets too hot, but I'm confused by a no crank only when hot symptom....
 

TMSBOSS

Spending my pension on car parts and track fees.
7,529
5,245
Exp. Type
HPDE
Exp. Level
10-20 Years
Illinois
A hot engine would crank a bit easier, But. The challenge is not with the engine. The heat causes problems with the cables and the starter. Resistance goes up, power down. In some extreme cases heat can cause a starter solenoid to seize.. Big block chevys were famous for this. Park for 5 minutes and the starter won’t crank. Wait until the engine compartment and starter cool and they crank right over.
 

TMO Supporting Vendors

Top