Stillen/GTM Supercharger Pros, Cons, and Questions
06-23-2010, 06:12 PM
#92
Administrator
Do Motorcycles with nearly 12:1 compression run too hot? Lets not forget they rev into the stratosphere.
Does the M3 with with a compression of 12:1 run too hot? It also revs higher.
What about diesels that typically run 18:1? They're usually turbocharged too, albiet with much lower redlines.
Ferrari? Lambo? Porsche?
Compression is simply a way to make power. The VQ35HR doesn't suffer from the catastrophic heat problems that the VQ37VHR suffers, and compression is nearly identical.
Does the M3 with with a compression of 12:1 run too hot? It also revs higher.
What about diesels that typically run 18:1? They're usually turbocharged too, albiet with much lower redlines.
Ferrari? Lambo? Porsche?
Compression is simply a way to make power. The VQ35HR doesn't suffer from the catastrophic heat problems that the VQ37VHR suffers, and compression is nearly identical.
Simple thermodynamics, there's no such thing as an adiabatic compression.. Anytime you compress a gas, it'll heat up whether you like it or not.. Throw some fuel with that and burn it and you're looking at a lot of heat generated! The challenge now is to throw this heat out of the engine bay
06-23-2010, 06:26 PM
#93
Remember, all those mid and rear engined cars you mentioned have ducts funneling air in to help cool things down. Just because they're temps don't go high doesn't mean they don't produce heat, they do.. but they're much better at cooling than our VQ37s.
Simple thermodynamics, there's no such thing as an adiabatic compression.. Anytime you compress a gas, it'll heat up whether you like it or not.. Throw some fuel with that and burn it and you're looking at a lot of heat generated! The challenge now is to throw this heat out of the engine bay
Simple thermodynamics, there's no such thing as an adiabatic compression.. Anytime you compress a gas, it'll heat up whether you like it or not.. Throw some fuel with that and burn it and you're looking at a lot of heat generated! The challenge now is to throw this heat out of the engine bay
I hate to do this but:
Celica (3SGE Beams, 11:1 compression, 1.8L making 200hp)
Civic SI (K20, 11:1 compression, 2.0L making 200hp)
S2000 (F20C/F22C 11:1 compression, 2.0/2.2L making 240hp)
These are all port injected cars; there's no fuel being injected after compression to absorb heat.
To put it in perspective, the N54 does have heat issues as well, but it was promptly addressed and fixed with an oil cooler. However, the Toyota 2GR-FSE is nearly 12:1, and doesn't suffer from cooling issues at all(and makes more torque than the VQ to boot).
So, the question is, how do we fix this?
We need a guinea pig for a frankenstein engine
06-23-2010, 08:00 PM
#95
Registered User
N54's still have heat issues even with a factory cooler. Hell my friend has an AR Design Stage 2 cooler (that's two oil coolers total) and it still goes up to 250F with a single 60-130mph run.
06-23-2010, 09:36 PM
#97
Administrator
06-23-2010, 10:02 PM
#98
Engine design. Simple as that. That is the number one contributor. You can break down every single element that causes heat in an engine but in the end it all comes down to how you handle that heat. You need to factor in how you're going to manage the heat, where it comes from, how you're going to move it, where it's going to go. I believe the design is not up to what it should have been. Maybe the cooling system isn't big enough. Maybe the radiator isn't getting enough air. Maybe they are using the wrong coolant, who knows. You may laugh at the last one but anyone who has been reading about the issues with the brakes knows that Nissan uses a crap brake fluid.
It's already been said, an oil cooler is a bandaid in this situation. It's a good idea in every car but the temps are just too damn high. Something isn't right.
I've been wondering why there isn't talk about running a lower coolant thermostat. Anyone know why that isn't a normal mod for these engines? It's common practice on most everything else.
It's already been said, an oil cooler is a bandaid in this situation. It's a good idea in every car but the temps are just too damn high. Something isn't right.
I've been wondering why there isn't talk about running a lower coolant thermostat. Anyone know why that isn't a normal mod for these engines? It's common practice on most everything else.
06-23-2010, 10:06 PM
#99
Lower temp thermostat just turns the fans on earlier. Track speeds push more air through than having the fans on; in that environment, the car's ability to dissipate heat must be greater than the car's ability to generate it.
When you're standing still, the car can barely dissipate heat, so the fans turn on to assist; this is where the thermostat helps.
When you're standing still, the car can barely dissipate heat, so the fans turn on to assist; this is where the thermostat helps.
06-23-2010, 10:29 PM
#100
Administrator
Engine design. Simple as that. That is the number one contributor. You can break down every single element that causes heat in an engine but in the end it all comes down to how you handle that heat. You need to factor in how you're going to manage the heat, where it comes from, how you're going to move it, where it's going to go.
06-23-2010, 10:53 PM
#101
06-23-2010, 11:56 PM
#102
I didn't miss your point. The higher compression is not the "contributor", it's the insufficient cooling or poor design. If you're looking at what causes the heat, it's just about every moving part in the engine. If you were to lower the compression ratio in this engine, you wouldn't be removing "extra heat" and solving any problem.
06-24-2010, 01:34 AM
#104
Lower temp thermostat just turns the fans on earlier. Track speeds push more air through than having the fans on; in that environment, the car's ability to dissipate heat must be greater than the car's ability to generate it.
When you're standing still, the car can barely dissipate heat, so the fans turn on to assist; this is where the thermostat helps.
When you're standing still, the car can barely dissipate heat, so the fans turn on to assist; this is where the thermostat helps.
What????? Coolant thermostats turn on fans? Having control of the fans would also be a nice touch but how does the thermostat turn on the fans?