THE ULTIMATE 944 HEAD GASKETS ARE OUT!!
04-01-2003 | 06:40 PM
#18
Drive-by provocation guy
Rennlist Member
Rennlist Member
Joined: Apr 2002
Posts: 10,439
Likes: 0
From: NAS PAX River, by way of Orlando
Knock kills engines good!!!!
Knock or detonation or pre ignition ALL has to do with heat. If you can keep the engine cool enough you can, in theory, run all the boost you want. You can even run very lean, as long as there is some external cooling apparatas to compensate for the high temps that will arise from running lean. You can run 87 octane with 20 psi, as long as you can keep the motor cool enough to not knock. Instead of $175 for a super duper head gasket "insurance policy", just add a water/alch injection system. Runs cooler, more boost,more hp, more advance and one super duper knock insurance policy. Not to take any business away from anyone by any means. Just focusing on the "insurance policy" reason for purchasing a high end head gasket.
Knock or detonation or pre ignition ALL has to do with heat. If you can keep the engine cool enough you can, in theory, run all the boost you want. You can even run very lean, as long as there is some external cooling apparatas to compensate for the high temps that will arise from running lean. You can run 87 octane with 20 psi, as long as you can keep the motor cool enough to not knock. Instead of $175 for a super duper head gasket "insurance policy", just add a water/alch injection system. Runs cooler, more boost,more hp, more advance and one super duper knock insurance policy. Not to take any business away from anyone by any means. Just focusing on the "insurance policy" reason for purchasing a high end head gasket.
04-01-2003 | 08:39 PM
#19
Burning Brakes
Joined: Nov 2001
Posts: 1,084
Likes: 0
From: San Diego
"You can run 87 octane with 20 psi, as long as you can keep the motor cool enough to not knock."
umm, not really....
First off, there is detonation caused by heat, and then there is detonation caused by bad gas/low octane. Proof, dyno a car on 87 octane, at 85 degrees room temp, engine running at 180degrees run 20 psi boost. It will knock, now..drain the gas, throw in 100 octane..BAM! No detonation, same temps.....better gas cures it. Adding gas of the same octane will overcome detonation to a degree, and so will water...but at a point, running low octane, you will be pouring soo much water or gas to the engine it will not burn and you won't make power.
Just tune the car correctly, and don't skip on the good gas. You can run all the steel headgaskets you want.
Water injection seems to me to be one more thing to go wrong. Think about it, its a separate system, you tune it perfectly to match your boost...what are the chances the water injection can fail? Then maybe you pop a gasket or worse..fill your cylinders with water? I think tuning for big HP needs to be as simple as you can possibly make it, try to keep items that can fail to a minimum. The less you build into it, the less chances of failure.
My thoughts only.
Take Care!
umm, not really....
First off, there is detonation caused by heat, and then there is detonation caused by bad gas/low octane. Proof, dyno a car on 87 octane, at 85 degrees room temp, engine running at 180degrees run 20 psi boost. It will knock, now..drain the gas, throw in 100 octane..BAM! No detonation, same temps.....better gas cures it. Adding gas of the same octane will overcome detonation to a degree, and so will water...but at a point, running low octane, you will be pouring soo much water or gas to the engine it will not burn and you won't make power.
Just tune the car correctly, and don't skip on the good gas. You can run all the steel headgaskets you want.
Water injection seems to me to be one more thing to go wrong. Think about it, its a separate system, you tune it perfectly to match your boost...what are the chances the water injection can fail? Then maybe you pop a gasket or worse..fill your cylinders with water? I think tuning for big HP needs to be as simple as you can possibly make it, try to keep items that can fail to a minimum. The less you build into it, the less chances of failure.
My thoughts only.
Take Care!
04-03-2003 | 04:02 PM
#21
Racer
Joined: Aug 2002
Posts: 457
Likes: 0
From: San Diego, CA
About running 20psi on 87 octane with alc/water injection...
Sorry, but John is correct. Yes, cooler temps allow you to run more boost / timing / etc. Detonation is also caused by pre-ignition, and not just temperature.
As such, to run more boost you can:
(a) Use a "bigger" turbo that has its compression map optimized for the level of boost you wish to run (thus, the compressed air will be relatively cooler) and/or use a bigger intercooler - this should net a little difference in the amout of boost you can run.
(b) Inject alcohol/water mix. This is good because it cleans the engine while its circulating through. However, this isn't a "magic" solution that will allow you to run infinate amounts of boost without descent gas, etc. If a car was able to run say, 17psi on pump gas before detonatoin, now the car can run say 20 psi - which it could have done with race gas anyway.
Keep this in mind - when you run NOS, the intake manifold gets ICE COLD. Does that mean that you're not going to ping? No. Sure, the cylinder temps are cold, but you can still gernade the motor.
Food for thought.
Sorry, but John is correct. Yes, cooler temps allow you to run more boost / timing / etc. Detonation is also caused by pre-ignition, and not just temperature.
As such, to run more boost you can:
(a) Use a "bigger" turbo that has its compression map optimized for the level of boost you wish to run (thus, the compressed air will be relatively cooler) and/or use a bigger intercooler - this should net a little difference in the amout of boost you can run.
(b) Inject alcohol/water mix. This is good because it cleans the engine while its circulating through. However, this isn't a "magic" solution that will allow you to run infinate amounts of boost without descent gas, etc. If a car was able to run say, 17psi on pump gas before detonatoin, now the car can run say 20 psi - which it could have done with race gas anyway.
Keep this in mind - when you run NOS, the intake manifold gets ICE COLD. Does that mean that you're not going to ping? No. Sure, the cylinder temps are cold, but you can still gernade the motor.
Food for thought.
