why do people blow their engines? Is it because EGT goes to high?

Am I right - if I don't have detonation and EGT in ok - I will not blow the engine?

What's normal EGT?

 

"normal" EGT depends on the load on the engine, where you are measuring EGT from, and the cam timing.

I way to broad generalizations....1800 F+ is to high
"normal" is roughly 1200 F at light load and up to 1600 F at high load.

Engine's don't "blow"...they suck. When someone "breaks" and engine, it's usually in the Crankshaft/rod/wristpin/piston area. It's usually due to over loading, under oiling, or detonation. In very high HP applications, you can actually do damage to the BLOCK itself (crack it or twist it)(non hyundai, ford 4.6L V8's have this problem), but usually the sub components break before the block itself gives out.

 

I talked to a guy from Ukrainian piston factory. And he told me that for reaching 300 hp (I just ask him this number) it's highly recommended to use oil spraying on the bottom of the pistons to cool them down.

It's also depends on how long 300 hp will be reched. For example for drag racing it's only 15-20 seconds, so piston will not get too hot.


So I thought alot of problems are from too high temperature in combustion chamber (from more air+fuel and more load).

 

It depends on what the piston is made out of as to how well it will deal with high temps. Forged pistons deal with high temps better than cast pistons do.

One LONG drag race if 300 HP takes 15-20 seconds.

Seriously....

Piston oil squirters are a good idea for piston cooling. Our engine's done come with them, but they can be added by tapping the oil galley that runs along near the bottom of the block about 2" below the bottoms of the cylinders. It would be a custom job to do it to a beta, but Mitsu 4G63 blocks come with them. They are fairly common on turbocharged motors.

The are other tricks to cooling down the pistons. Ceramic coating the piston tops to reflect/prevent absorption of heat. You can also ceramic coat the combustion chamber roof as well. This would raise EGT's since the heat is not absorbed by the engine, but would produce more power for a turbocharger. Going gonzo would also mean ceramic coating the exhaust ports, exhaust manifold, turbine housing, turbine blades, and downpipe. The more heat you keep in the exhaust the more power the exhaust has to spin the turbocharger. The more heat you keep out of the engine, the higher the EGT's are. That's why there really isn't a hard and fast rule for EGT. a 1-2" difference in EGT probe placement can also show a 100 to 200F temp difference (depending on exhaust manifold shape/design/materials).

If you're trying 300 WHP on stock pistons, yeah, I'd reccomend oil squirters. If you're going with 300 WHP on forged pistons, you shouldn't have a problem.