We Took the 5.2L Predator-Powered Mk4 to the Dyno

[Mad Dog]

We built this Mk4 Roadster with the crew at Hot Rod Brothers the other year, and it features the 5.2L Predator supercharged motor along with Tremec 5-speed transmission, IRS, and 17″ Halibrand wheels. Factory Five tech Dan G. took the Roadster up to Cohesion Motorsports in Lawrence, MA to tune the engine and see what it would do on the dyno. Check out his report in this video.



The results were 654.4 HP and 533.8 trq which is right about where it should be for the stock Predator engine. And remember, this is in a car that weighs right around 2,400 lbs.



Check out more photos of this Roadster build here.



Thanks to the crew at Cohension Motorsports for their help at the dyno!

[toadster]

WOWSERS! That's a panty dropper!!

[Jim1855]

That'll be fun.
Jim

[Blitzboy54]

Registered in Montana... lol

[fauxbra5.0]

That's damn impressive, although Dan's messaging seems like they were a bit disappointed at the result. Regardless, 650hp in a 2400lb car would give a similar power/weight ratio as a McLaren Senna! That kind of power (if you can go 10/10ths) must absolutely scramble your brain...

[ProfessorB]

I watched the video and would like to point out that it produces 654 horsepower AT THE REAR WHEELS. I can only imagine what it produces at the flywheel.
.
My second observation: During the video Dan talks about engine cooling and says the weather was "humid". What difference does "humidity" make? PEOPLE cool less efficiently because we perspire and the evaporation of that is what cools us. Cars and engines don't "sweat" so humidity is not a factor in cooling.

[JJK]

I thought the same thing about the humidity comment. Even though it is called a radiator, the cars cooling is based predominantly on conduction heat transfer, not convection or radiation. Given that water conducts heat much more effectively than air, I would argue that higher humidity results in more efficient cooling. Now, higher humidity also affects the amount of usable oxygen in a predefined volume, so I would expect less power with higher humidity, even more so with a forced induction system. With higher humidity there is less air to mix with fuel compared to lower humidity, thus less bang in the cylinders. While this theory is sound, I have no idea the actual power loss from higher humidity , it could be negligible.

[toadster]

btw - watch to the end, the gopro is hilarious

[ProfessorB]

I thought the same thing about the humidity comment. Even though it is called a radiator, the cars cooling is based predominantly on conduction heat transfer, not convection or radiation. Given that water conducts heat much more effectively than air, I would argue that higher humidity results in more efficient cooling. Now, higher humidity also affects the amount of usable oxygen in a predefined volume, so I would expect less power with higher humidity, even more so with a forced induction system. With higher humidity there is less air to mix with fuel compared to lower humidity, thus less bang in the cylinders. While this theory is sound, I have no idea the actual power loss from higher humidity , it could be negligible.

JJK....I couldn't agree with you more. I actually thought about this, including the oxygen content of the air for combustion, and even the possible "anti-detonation" effect of the water content of the air (sort of like water injection). But what I think is that while humidity has a MAJOR effect on the cooling of human beings....the effect of relative air humidity is probably so small as to be negligable. Air temperature, on the other hand, does have an impact....both in cooling and producing power.