Hey Phunk, we tuned on a load based dyno and watch the overflow. Prior to running with open pipes, the coolant level would rise, but not overflow. The runs we made are roughly 8-10 seconds in 4th gear mostly. We never dide 5th gear because the dyno speed gets pretty scary...especially with a load based dyno. You could also feel the heat coming off the engine. When we removed the exhaust restriction, the coolant level never moved, and there was a notable decrease in engine bay temps.

I imagine your car would have been close to 600whp with the HKS F-Con, and an open exhaust.

The 550's are near the limit...thats for sure.

 

sharif: just FYI i never did have coolant boiling on the dyno... i would get a little raise in the overflow, but nothing to write home about and it would eventually go back down. It wasnt until I started giving it hell in the higher gears on the street where I started to really get hit with the cooling trouble. I would be curious if the exhaust backpressure drop was enough to eliminate this issue.

 

it appears so...and i'm getting my custom 3" true dual very soon

 

yes, Espirit Japan, with RB26, 600hp. and it's a track car.

 

Is this a physical example of the difference between inertia and load based dynos.

 

no. when tuning a car on the dyno i take several several minutes between passes as I make adjustments. When I was able to boil the coolant, it was when I did repeated runs in higher gears at loads that are much greater then a full sweep pass on any dyno.

 

Thats correct. I was pointing out that we used a load based dyno, which will apply a realistic load on the engine, especially at higher RPM. The load based dynos, if anything, would increase coolant temps at higher RPM...all things being equal, when compared to a dyno jet.

Of course it's difficult to replicate drag, wind resistance, etc, but on the dyno, G_Man's coolant overflow bottle never budged with the zero back pressure exhaust setup. Hope that helps.

 

No... more innaccurate dyno chat doesnt help.

I am curious, if I had just removed all the exhaust backpressure in my car, if that would have stabilized the heat issues I was having. But since I doubt this car your showing us will ever go thru what I had to put my car thru to cause the problems... I will never know... I am changing too much this time around to isolate exactly what fixed it. I promise you that your dyno there was not creating anywhere near the load or the heat of what I was doing with my car to create the issues.

Run the car down some back to back 1/4 mile, repeatadly take it up to 170mph, do some burnouts and 360's in 100 degree weather..... Report back after the car does more than make a dyno graph without having cooling system issues... and let us know if the everything stayed cherry. thats all I am saying

 

^^^Phunk^^^
My "chat" is not inaccurate. I was just pointing out that in my FOURTH gear runs, we are creating more load and heat than a dynojet inertia based dyno...that is an idisputable fact. A 1500lb drum (or whatever the exact weight is) spinning at 120mph is going to exert far less load on the motor than a load based dyno at the same speed.

My point is bring this up, was to let you know that we put more load on the motor than with a dynojet...thats all. I also acknowledge that your 5th and 6th freeway pulls put far more load on the motor than we did.

 

have the dyno software convert to a rpm versus time graph and i will do the same, and then we can dispute this indisputable fact.

 

hahha charles u told me all these stories and theories months ago... they are finally comming out onto the boards, hopefully once shes all fixedup after winter ill FINALLY get a spin in that beast