And . . .

It broke.

• After multiple runs at our test track and multiple rounds of racing in Edmunds U-Drags, I took our supercharged Dark Horse out for a track day at Buttonwillow Raceway Park.
• It wasn't long before issues cropped up: a rough-shifting transmission, an engine determined to overheat, and a plume of white smoke out the back.

Supercharger in road course cars are pretty much a big no no, so not a surprise there

It was a cool, 60 degree day, too.

However, data pulled from the car began to paint a picture. The engine's coolant temperature reached 240 degrees Fahrenheit at some point while the car was traveling 80 mph, indicating it had started to overheat. At this point, the dealer's theory was that the car had been "pushed too hard." Seriously?

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Does the car record data about coolant temperature? Is there even a coolant temperature sensor?

I’ve seen some automatic dark horse mustangs overheat their transmissions at Daytona and make impressive white smoke plumes coming from the rear

Junkyard Dog said:

It was a cool, 60 degree day, too.



Does the car record data about coolant temperature? Is there even a coolant temperature sensor?

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Im sure there is, def an Intake Air Temp sensor

Welp...S550 superiority, and S197 mastery. Figures.

Spark plug gaps. Figures.

"it's essential to adjust the spark plug gaps to account for the engine's new boosted state. And as the notes on the repair invoice show, the gaps hadn't been adjusted correctly during the supercharger's installation."

I wonder if Ford is making the dealer eat the repair cost because their tech didn't follow the instructions during the supercharger install.

There is a reason the GT500 has a nose full of coolers and vents. And it will still melt its cats in stock trim when driven hard for long enough. - basically long pulls in straights. The 'strap on' whipple kits have limited extra cooling, NA compression ratio, stock NA cats which are lower grade etc. Tough to keep alive in heavy stress even with factory warranteed kits. Best for street duty with limited loading.

CobaltFilly said:

Welp...S550 superiority, and S197 mastery. Figures.

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Making the power is one thing, cooling it is a completely different kettle of fish. That's why I'm always talking about it and why I think you have a good thing with your V6. Even if you have to go with a GT rad, it's really not that big of a deal.

BTW, I was at a shop with Ginetta GT cars in it last week. Those things run the same engine as you have. The guys working on the cars said they were tough little engines.

Dave_W said:

Spark plug gaps. Figures.

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Ya, I'm gonna call bullsiht on that diagnosis. The cats aren't sized to take that much flow/energy...neither is the cooling system.....neither is the trans....probably not the rear end, either. Making an 800 Hp car live on a racetrack is not an easy job.

TeeLew said:

Making the power is one thing, cooling it is a completely different kettle of fish. That's why I'm always talking about it and why I think you have a good thing with your V6. Even if you have to go with a GT rad, it's really not that big of a deal.

BTW, I was at a shop with Ginetta GT cars in it last week. Those things run the same engine as you have. The guys working on the cars said they were tough little engines.

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Yes, I am so glad I listened to you and everyone else on here. Progress is going swimmingly, cooling is optimal right now, no issues with any of the car. Currently dissecting the interior, one of the sponsors will finish out the rollcage, and then I have a guy teaching me auto body repair and paint and we will paint the interior...I'm thinking battleship grey.

Ginetta GT cars were my inspiration to continue building. I tried getting in contact with them to get more info on how to better the engine, but no luck in responses. Can you give me a number to the shop you were at? I have questions that I want to put into practice on the mustang. My dms are always open.

Sorry to derail thread, back to the main course.

Just this week I had a customer at our dealership asking me about SC kits for his 25 GT which he does some track days with. It’s a manual car but I strongly advised him against for the intended usage. Even up here in the GWN we can have 85-90 degree summer days wth lots of humidity, and I could just picture the issues he might have … this thread was very timely as a reminder for me.

Amazing how many garage built blown mustangs are for sale cheap. I would not want to touch one with a 10 foot pole. And tracking a forced induction brings on a whole new set of issues unless it’s built right. I wish ford had multi displacement coyotes so it did not rely on boosting it to get more power. Big drawback i think. Even this factory one “broke”