I found this video on Youtube of an S550 with twin turbos. He drives in advanced group HPDE days and does autocross as well. I was curious if he is here. He has huge amounts of aero. Anybody seen him out on the track?

I thought at first I knew the guy ( don't ) but the car sure lives up to the rules in the Ultimate Street Car Challenge which also emphasizes the creative nature and application of the car inside and out. Sweet work and beautiful machine so thanks for posting.

I've seen him post in TMO Facebook and Mustang Driver's Club here in CA (local time attack group).

Sounds like he could contribute here. I am very curious how he keeps that thing cool (or if he can keep it cool). Since he runs HPDE days, he either keeps it cool or has very short sessions.

So he talks about cooling starting at 11:10 time stamp on this video:

what kind of info are ya' looking for? i watched a couple videos and saw he's been fighting quite a few issues...which doesn't surprise me. he's making a lot of changes while trying to remain a street car and that's really hard to do without spending BIG bucks on the right equipment.

I have a local buddy with a twin turbo coyote that's gone through similar stuff here at COTA. but he's gutted his car, so he doesn't have the same packaging restraints that cause so many issues.

honeybadger said:

what kind of info are ya' looking for? i watched a couple videos and saw he's been fighting quite a few issues...which doesn't surprise me. he's making a lot of changes while trying to remain a street car and that's really hard to do without spending BIG bucks on the right equipment.

I have a local buddy with a twin turbo coyote that's gone through similar stuff here at COTA. but he's gutted his car, so he doesn't have the same packaging restraints that cause so many issues.

Click to expand...

Just how to keep it cool?


Is it even possible to have a twin turbo Mustang that can do a 30 minute session on track without having to run cool down laps or stop early?

What if you turn the boost down to 5 or 6 pounds? What of you run it on E85? What if you have a custom built radiator with more capacity than the Dark Horse radiator, add more supplemental oil cooling (a second oil cooler run in parallel with the stock Dark Horse oil cooler?)?

Since turbos can be adjusted electronically, I just keep thinking that there has to be a way to do it.

And, yeah, I love my car as a street car, but I do not want to install a Hellion twin turbo kit and then never again be able to go enjoy an HPDE day. Doing HPDE is way more fun that "pulls" on the street and way more fun than drag racing.

But if anybody is having success, I would love to learn more about how they did it.

I am not even that serious about doing a twin turbo, street and HPDE car myself, but I am insanely curious about it. Maybe one day if I can figure out a way to do it and make it reliable . . .

Note: I'm not a mechanical engineer, powertrain designer, or thermodynamicist. I'm just a reasonably smart guy who likes science.

Horsepower output of an engine is energy that is created by burning fuel in the engine, turning chemical bond energy into heat energy, and capturing some of that heat energy as mechanical energy moving the pistons and turning the crankshaft. The more horsepower you want, the more fuel you need and heat you'll make. There's no magical way to get more power without creating more heat in an internal combustion engine.

Of the heat energy created by the combustion, some is converted to mechanical energy driving the crank, some is removed by the exhaust gasses (and a turbo can convert part of that into mechanical energy to spin the intake impeller), and some is removed by the coolant (and oil). I've seen an estimate (of unknown reliability) that says the combustion energy is pretty evenly divided between crankshaft, exhaust, and coolant.

One mechanical horsepower (hp) is equivalent to approximately 2545 British Thermal Units per hour (BTU/h). For 1,000 hp at the crank, that's 2,545,000 BTU/h, and if the 1/3 rule of thumb is to be believed, that also what you'll need to remove through the coolant.

The engine's cooling and oiling systems try to remove enough heat to keep the engine from overheating. They're designed to do that at the stock power output, with most owners driving around town and on the highway. The factory designers have to balance packaging space and parts cost against the desire to cool an engine at full throttle for a 30-minute track session, and guess what wins - the bean counters. When you create more heat in the engine, you need more capacity to remove it as well. But that capacity really comes in two parts - the ability to absorb the heat from the engine, and the ability to shed the heat (usually to the atmosphere).

Here are a couple articles that talk about choosing the cooling system components:

And here's a student research paper doing the calculations for cooling of an auto radiator:

The general rule of thumb is that for each quanitity of gas: 1/3 of the energy goes off the crank, 1/3 goes out the exhaust, and 1/3 of it goes out the cooling system. I think it actually works out to more like 40:30:30, but the reality of the deal is that the more you take off the crank, the more you have to get out of the cooling system.

E85 is meant to help cooling to some extent, but it's nothing like the effect you get from something like methanol.

You'd probably lose boost control to some extent if you were running very low boost levels, but that would definitely help the engine stay cool.

At the end of the day, you can run any power level you want as long as you can cool it. I think if you wanted to put auxiliary rads and and oil cooler in the side intakes of a Shelby or Mach 1-style nose, then you could cool quite a bit of boost. It would be a lot of work.

Junkyard Dog said:

Just how to keep it cool?

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-or-​

Is it even possible to have a twin turbo Mustang that can do a 30 minute session on track without having to run cool down laps or stop early?

What if you turn the boost down to 5 or 6 pounds? What of you run it on E85? What if you have a custom built radiator with more capacity than the Dark Horse radiator, add more supplemental oil cooling (a second oil cooler run in parallel with the stock Dark Horse oil cooler?)?

Since turbos can be adjusted electronically, I just keep thinking that there has to be a way to do it.

And, yeah, I love my car as a street car, but I do not want to install a Hellion twin turbo kit and then never again be able to go enjoy an HPDE day. Doing HPDE is way more fun that "pulls" on the street and way more fun than drag racing.

But if anybody is having success, I would love to learn more about how they did it.

I am not even that serious about doing a twin turbo, street and HPDE car myself, but I am insanely curious about it. Maybe one day if I can figure out a way to do it and make it reliable . . .

Click to expand...

sorry I missed this cmpletely.

I would reach out to Paul's Automotive Engineering (I think they're a sponsor?). They road raced a twin turbo 5.2 and won a few championships and broke some records. I believe one of the many keys was low boost. IIRC, it made around 8lbs and they did a ton of cooling and weight reduction.

From what I've seen, running 25+mins on a road course with a turbo car requires one of two things - low boost or medium boost and a crap ton of complicated cooling (cant stack exchangers because you lose too much efficiency).

Either way - SUPER aggressive weight reduction is one of the best things you can do to help. less weights means less stress and less heat.

I brought the boost down by 5 psi (12 to 7) by changing the cam timing on my 2011 Coyote in my Mustang GT with a PD blower on it. Power didn't change, based on my speed and acceleration measurements accelerating down a long straight, but the temps came down far enough that the engine could do a 30 minute session (80 degree weather) without any heat problems.