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S550 AJ Hartman Aero's GT350 Build Build Thread Profile - S550 Mustangs

What's the difference between the Fulcrum and the Apex wings? Is it that the Apex is modular and the Fulcrum is not?
Our Fulcrum 14 is a 14" cord single element wing. The Apex line of wings, like you mentioned, are meant to be modular. The Apex 8 is an 8" main element that works great on its own should you not need a lot of rear downforce or working within some class rules or whatever the case may be. Then we have 2 upper flap options turning the Apex 8 into either an Apex 12 or Apex 15, depending on your needs to balance front aero. Below is a video from way back when I made the first Apex wings.

 

JDee

Ancient Racer
1,512
1,533
Exp. Type
W2W Racing
Exp. Level
20+ Years
halfway between Mosport and Shannonville
I know little of aero and not sure I want to go down that rabbit hole. I wonder does the added downforce from a wing offset the loss in speed from drag on long straights? I have stock Ford aero that came with PP1 in 2016, bare back and factory splitter only.
Mosport is a very fast track with only 1 slow corner and I wonder if there would be any net gain from a rear wing, given the drag it adds? The car runs in the Open group now and it fits in with that group quite well, pretty much a mid pack car, passes as often as it gets passed.
 
I know little of aero and not sure I want to go down that rabbit hole. I wonder does the added downforce from a wing offset the loss in speed from drag on long straights? I have stock Ford aero that came with PP1 in 2016, bare back and factory splitter only.
Mosport is a very fast track with only 1 slow corner and I wonder if there would be any net gain from a rear wing, given the drag it adds? The car runs in the Open group now and it fits in with that group quite well, pretty much a mid pack car, passes as often as it gets passed.
If aero didn't work, would the fastest cars run it? Since you asked only about a wing, I'd say you may slow up since the aero would then be extremely unbalance. But if you did a wing and splitter that result in a balanced aero setup, your lap times will absolutely come down if you utilize the extra grip. So what if you give up 2-3mph at the very end of the long straight when you carry that 2-3 mph more through every turn? Thats a bit simplified and track dependent, but yeah you should get quicker. A few years ago I went from my American Iron legal aero to ST2 aero which is much much larger, and at NJMP's lightning circuit, the last turn is a big sweeper leading onto the front straight. I was able to carry 5-6 mph more through that turn and by the time I got to the end of the straight to T1, was still carrying 1-2 mph over my "less aero" setup. So I carried a few more mph down the entire front straight and ended up going like 1.5 seconds quicker than my previous best lap there. So don't just think aero will slow you down.
 
12
6
Exp. Type
HPDE
Exp. Level
20+ Years
Charlotte
If aero didn't work, would the fastest cars run it? Since you asked only about a wing, I'd say you may slow up since the aero would then be extremely unbalance. But if you did a wing and splitter that result in a balanced aero setup, your lap times will absolutely come down if you utilize the extra grip. So what if you give up 2-3mph at the very end of the long straight when you carry that 2-3 mph more through every turn? Thats a bit simplified and track dependent, but yeah you should get quicker. A few years ago I went from my American Iron legal aero to ST2 aero which is much much larger, and at NJMP's lightning circuit, the last turn is a big sweeper leading onto the front straight. I was able to carry 5-6 mph more through that turn and by the time I got to the end of the straight to T1, was still carrying 1-2 mph over my "less aero" setup. So I carried a few more mph down the entire front straight and ended up going like 1.5 seconds quicker than my previous best lap there. So don't just think aero will slow you down.
@AJ Hartman I realize this is an over simplification, but I think it’s true that aero benefits become measurable at moderate speeds and drag can hurt top speed to a degree. And I know that it’s all track and car dependent and tunable. But, are there some guidelines (rule of thumb) that can help me evaluate the potential benefits of adding aero aids?
 
@AJ Hartman I realize this is an over simplification, but I think it’s true that aero benefits become measurable at moderate speeds and drag can hurt top speed to a degree. And I know that it’s all track and car dependent and tunable. But, are there some guidelines (rule of thumb) that can help me evaluate the potential benefits of adding aero aids?
Best rule of thumb I know, more Df equals more grip. More grip allows you to go faster.
 
12
6
Exp. Type
HPDE
Exp. Level
20+ Years
Charlotte
Best rule of thumb I know, more Df equals more grip. More grip allows you to go faster.
I read your NJMP story, and it backs up your assertion. I’m also on the keep it simple program so I can buy in to the position that more DF = more grip = more speed (through the corners) = lower lap times.

That said, I was hoping you might pull back the curtain a little and share your thoughts on the lowest speeds where aero aids begin to actually produce enough new grip to benefit lap times.

I appreciate your willingness to share what you know and your contributions to helping us go faster.
 
I read your NJMP story, and it backs up your assertion. I’m also on the keep it simple program so I can buy in to the position that more DF = more grip = more speed (through the corners) = lower lap times.

That said, I was hoping you might pull back the curtain a little and share your thoughts on the lowest speeds where aero aids begin to actually produce enough new grip to benefit lap times.

I appreciate your willingness to share what you know and your contributions to helping us go faster.
Unfortunately there isn't an answer to that open of a question. Wayyy to many variables to just have a flat answer. If you said, "hey, I'm running this class, heres the rules, this is my chassis, heres my budget and these are the tracks I'm running." I could then narrow down what would be a good aero solution for you. But theres no way to answer such an open question.
 

JDee

Ancient Racer
1,512
1,533
Exp. Type
W2W Racing
Exp. Level
20+ Years
halfway between Mosport and Shannonville
If aero didn't work, would the fastest cars run it? Since you asked only about a wing, I'd say you may slow up since the aero would then be extremely unbalance. But if you did a wing and splitter that result in a balanced aero setup, your lap times will absolutely come down if you utilize the extra grip. So what if you give up 2-3mph at the very end of the long straight when you carry that 2-3 mph more through every turn? Thats a bit simplified and track dependent, but yeah you should get quicker. A few years ago I went from my American Iron legal aero to ST2 aero which is much much larger, and at NJMP's lightning circuit, the last turn is a big sweeper leading onto the front straight. I was able to carry 5-6 mph more through that turn and by the time I got to the end of the straight to T1, was still carrying 1-2 mph over my "less aero" setup. So I carried a few more mph down the entire front straight and ended up going like 1.5 seconds quicker than my previous best lap there. So don't just think aero will slow you down.

Thanks for the info, much appreciated. I don't doubt aero works, for sure it does. I just wonder if it works enough to be valuable at every track with every car. I'm certainly not opposed to adding a wing, I'm just not sure that it's actually going to help much for my situation.

I mainly run at Mosport where the slowest corner on the track (turn 5) leads onto the longest straight. That corner is a very tight 90 degree that I am taking at 50 mph at the apex. I doubt that more aero is going to increase speed through that corner, so I'm starting the straight at the same speed I am now, wing or not.

You pretty much dig out of a hole there onto a long uphill straight that has 2 "corners" on it which are taken flat out, it is essentially a long curving straight. I'd guess close to 40% of the track is in that straight. So any extra drag from a wing is really going to hurt speed all the way up that straight. I usually get 147 mph before I have to brake for Turn 8, a very fast right hander.

Most of the other corners are a lot faster and are connected by medium length straights that still result in 120+ mph speeds. Turns 1, 2, 3, 4 and 8 are pretty fast, in the 90 to 120 mph range. Turns 9 and 10 are tighter and slower and 5 is very slow So the question is does the speed I gain in the corners offset the speed I lose on the straights from drag? This is not a big HP car, it's a stock motor. Not many closed cars are quicker than mine in the corners, but my car is one of the slower ones on the straight already. I run in Open class. I see where I could likely gain speed in 5 corners, but would that offset the drag losses on all the straights?

My car doesn't lack rear grip, front grip is the bigger problem. I'd likely need to add aero to the front and that creates a whole new set of logistical problems. I already have a hard time getting it on and off the trailer just with the stock splitter because the car is much lower than stock with the FR3 suspension. Plus the whole nose on the 550s is a real PITA with the flimsy mounts for it, adding more splitter means more beefing up of everything and that's not easily done in a home garage. So it's not just 'add a wing go faster', there's outliers in everything and cars/race tracks are no different.

I know a guy who put a wing on his Mustang, have to see what his experience is with it.
You lurking out there Brad? Call me. LOL.
 
Thanks for the info, much appreciated. I don't doubt aero works, for sure it does. I just wonder if it works enough to be valuable at every track with every car. I'm certainly not opposed to adding a wing, I'm just not sure that it's actually going to help much for my situation.

I mainly run at Mosport where the slowest corner on the track (turn 5) leads onto the longest straight. That corner is a very tight 90 degree that I am taking at 50 mph at the apex. I doubt that more aero is going to increase speed through that corner, so I'm starting the straight at the same speed I am now, wing or not.

You pretty much dig out of a hole there onto a long uphill straight that has 2 "corners" on it which are taken flat out, it is essentially a long curving straight. I'd guess close to 40% of the track is in that straight. So any extra drag from a wing is really going to hurt speed all the way up that straight. I usually get 147 mph before I have to brake for Turn 8, a very fast right hander.

Most of the other corners are a lot faster and are connected by medium length straights that still result in 120+ mph speeds. Turns 1, 2, 3, 4 and 8 are pretty fast, in the 90 to 120 mph range. Turns 9 and 10 are tighter and slower and 5 is very slow So the question is does the speed I gain in the corners offset the speed I lose on the straights from drag? This is not a big HP car, it's a stock motor. Not many closed cars are quicker than mine in the corners, but my car is one of the slower ones on the straight already. I run in Open class. I see where I could likely gain speed in 5 corners, but would that offset the drag losses on all the straights?

My car doesn't lack rear grip, front grip is the bigger problem. I'd likely need to add aero to the front and that creates a whole new set of logistical problems. I already have a hard time getting it on and off the trailer just with the stock splitter because the car is much lower than stock with the FR3 suspension. Plus the whole nose on the 550s is a real PITA with the flimsy mounts for it, adding more splitter means more beefing up of everything and that's not easily done in a home garage. So it's not just 'add a wing go faster', there's outliers in everything and cars/race tracks are no different.

I know a guy who put a wing on his Mustang, have to see what his experience is with it.
You lurking out there Brad? Call me. LOL.
If it makes you feel better, I just ran VIR this weekend which is a similar setup where Turn 12 (Oak Tree) is about the same, a 50 mph turn onto the long straight. Yeah, I lost about 4-5 mph at the end of the straight. BUT, I went from a (theoretical) 2:12.5 with the GT350R aero, all the way down to a 2:08.3 after adding my wing and splitter since I picked up time in several other places. So take that for what its worth. I did the 2 morning sessions without it, and then 2 after noon sessions with aero and dropped about 4 seconds. I also had to figure out a board configuration to load and unload the car but wasn't to bad. Our splitter kits come with everything needed to bolt to your car securely. I'll be doing a video of the whole weekend pretty soon.
 
Couple pictures from the weekend. Saturday I ran the first 2 sessions with stock GT350R aero. Then at lunch, added my wing and splitter and ran 2 more sessions. Non aero I had a 2:12.5 (predicted) was my best. With my aero, 2:08.3 actual lap time. I'm sure I left some time on the table in the non aero setup, but I'm also sure I left some time on the table in the aero setup. Sunday unfortunately rained in the morning session. Was kinda dry but a drizzle second session. Finally added canards sunday afternoon for one session but on my 2:07.9 (predictive) was messed up by the checkers coming out at Turn 12. Womp womp. But still a fun weekend and can say that our aero kit (5" splitter and Fulcrum 14 wing) is worth around 4 seconds at VIR over GT350R aero.image_6487327.JPGimage_6483441 (1).JPGimage_6483441.JPGimage_6483441 (2).JPG
 

Mad Hatter

Gotta go Faster
4,663
3,383
Santiago, Chile
Could you give us an idea about how top speed is affected by the additional cool aero stuff?? One thing is a better lap time, and another is passing on the straights. Curious about the trade offs. Does the aero affect your top speed significantly?
 
5,495
6,445
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
Could you give us an idea about how top speed is affected by the additional cool aero stuff?? One thing is a better lap time, and another is passing on the straights. Curious about the trade offs. Does the aero affect your top speed significantly?
As a non professional my answer would be:
Well designed, efficient aero gives much much more than it takes. Poorly designed aero….just the opposite.
 
Could you give us an idea about how top speed is affected by the additional cool aero stuff?? One thing is a better lap time, and another is passing on the straights. Curious about the trade offs. Does the aero affect your top speed significantly?
This the exact issue I'm up against with my race car (the 99 Mustang with huge amounts of downforce). I think given the combo of VIR and my aero load and associated drag, it would be more "raceable" if I took aero out of that car to increase straight line speed since the only real places to pass are at the end of the straights on that track. But for raw lap time, I will most likely be slower. Now back to the GT350, going from the R aero to my splitter and wing did cost me about 4-5mph top end on the back straight. Some people may think thats crazy but I dove into my data just on this topic. I was able to accelerate a bit sooner so was actually up about 4-5 tenths up to about 115-120mph until the non aero runs overtook towards the end of the straight. I did a delta from corner exit to 120mph and the aero runs were up that 4-5 tenths, and then a delta from 120mph to braking and the non aero runs only made back about 1 tenth. So the total gain was a few tenths quicker for the aero setup from turn11 apex to the brake zone. I'll dive into a bit more in my data video from the weekend.
 

Frank.JD.Perez

FJD Performance
260
411
Exp. Level
5-10 Years
Pleasanton/Hayward, CA
This the exact issue I'm up against with my race car (the 99 Mustang with huge amounts of downforce). I think given the combo of VIR and my aero load and associated drag, it would be more "raceable" if I took aero out of that car to increase straight line speed since the only real places to pass are at the end of the straights on that track. But for raw lap time, I will most likely be slower. Now back to the GT350, going from the R aero to my splitter and wing did cost me about 4-5mph top end on the back straight. Some people may think thats crazy but I dove into my data just on this topic. I was able to accelerate a bit sooner so was actually up about 4-5 tenths up to about 115-120mph until the non aero runs overtook towards the end of the straight. I did a delta from corner exit to 120mph and the aero runs were up that 4-5 tenths, and then a delta from 120mph to braking and the non aero runs only made back about 1 tenth. So the total gain was a few tenths quicker for the aero setup from turn11 apex to the brake zone. I'll dive into a bit more in my data video from the weekend.
ive never read something before in my life that i completely dont understand and DO understand at the same time... lol

pretty awesome how much you can analyze this data
 

Mad Hatter

Gotta go Faster
4,663
3,383
Santiago, Chile
This the exact issue I'm up against with my race car (the 99 Mustang with huge amounts of downforce). I think given the combo of VIR and my aero load and associated drag, it would be more "raceable" if I took aero out of that car to increase straight line speed since the only real places to pass are at the end of the straights on that track. But for raw lap time, I will most likely be slower. Now back to the GT350, going from the R aero to my splitter and wing did cost me about 4-5mph top end on the back straight. Some people may think thats crazy but I dove into my data just on this topic. I was able to accelerate a bit sooner so was actually up about 4-5 tenths up to about 115-120mph until the non aero runs overtook towards the end of the straight. I did a delta from corner exit to 120mph and the aero runs were up that 4-5 tenths, and then a delta from 120mph to braking and the non aero runs only made back about 1 tenth. So the total gain was a few tenths quicker for the aero setup from turn11 apex to the brake zone. I'll dive into a bit more in my data video from the weekend.
Looking forward to seeing what you find!! Am happy with my aero so far, but am finding it a little harder to pass from 140mph top speed going to braking. I can get them on the brakes, but I feel little slower passing on power. If I add a couple degrees to the rear wing the car handles great but I loose 7mph right away.
 

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