Shaving the head

[Tercel Drifter]

The cylender head...Duh;).  Anyways increasing compression.  Anyone with suggestions, so that I don't blow myself up (detonate) when I hit the nitrous button? I was thinking just run higher octane.  And not go nuts with how much gets shaved.

[Darkest Edge]

Use a thinner head gasket to raise the compression.

[Don Fusskinrolla]

Use a thinner head gasket to raise the compression.

i don't know if this is possible.

But, your post was about how to NOT destroy your engine.  The result of shaving the head will give you a higher compression ratio, which in turn puts alittle more stress on yor engine components.  Not enough though to cause it to break.  Sometimes, people shave the head to just make a better mating surface between the block and head.  You need to remember that our heads are aluminum, they are bending contantly due to heat and cold... which can cause a leaky head gasket.

but that's a whole other subject.  You want nitrous.  The only way in which you will not destroy your engine is basically by beefing up your car.  Just like a turbo application.

It's all about a term called, "Factor of Safety".  it's a non value ratio of actual stress divided by theoretical stress.  Theoretical stress is what is calculated.  In this case by the engineers at Toyota.  If you by installing nitrous due not in turn "beef up" you internals, the actual stress goes up, the theoretical stress stays the same, you might in reality be decreasing the "safety range of proper engine component stress rigidity" by half.

in street terms: you just f'cked up your engine.

[Don Fusskinrolla]

i just remembered.

Detonation is a tricky subject.  I honestly don't believe you can simply solve it by having higher octane.  See detonation is caused by the cylinder operating in a higher temperature.  Because pressure and temperature are proportional, the higher the temperature, the lower the piston has to move up the cylinder wall to cause ignition.  We all know that this is bad.

I think, that if you have a higher octane gas, this will in fact RAISE your block temperature, because higher octane also burns at a higher temperature.  So i really don't think it serves a purpose, especially for N/A applications.

like I said earlier, your nitrous will add more stress to the system.  it will put more stress in the form of pressure and heat.  Build your rings, pistons, rods, valves, springs, and all your seals.

GL!

[GrandLordKhorne]

You could run a bigger turbo and no bottle...  That may prevent blowing up...

[Ben]

The cylender head...Duh;). Anyways increasing compression. Anyone with suggestions, so that I don't blow myself up (detonate) when I hit the nitrous button? I was thinking just run higher octane. And not go nuts with how much gets shaved.

What's your mods?  What engine?  How much do you want to increase the compression by?  How much of a shot are you going to run or are you running?  Wet or dry?

[Tercel Drifter]

Thanks for the help guys. I'm running a shot at 35% of the stock motor's hp.  The head is being replaced with a head that is milled, port polished, and has a 5 angle job. the blot is stock. (I just have a bunch of bolt ons)

[Dark-Hawk]

i just remembered.
 
Detonation is a tricky subject. I honestly don't believe you can simply solve it by having higher octane. See detonation is caused by the cylinder operating in a higher temperature. Because pressure and temperature are proportional, the higher the temperature, the lower the piston has to move up the cylinder wall to cause ignition. We all know that this is bad.
 
I think, that if you have a higher octane gas, this will in fact RAISE your block temperature, because higher octane also burns at a higher temperature. So i really don't think it serves a purpose, especially for N/A applications.
 
like I said earlier, your nitrous will add more stress to the system. it will put more stress in the form of pressure and heat. Build your rings, pistons, rods, valves, springs, and all your seals.
 
GL!

Higher octane allows you to run more timing with less knock.
 
However I've never heard of "shaving" the head to raise the compression ratio. What type of car do you have? You don't really run a "35%" increase of Nitrous, they come in certain size shots .

[Tercel Drifter]

I know, but I calculated what approx. a 35% increase in power would be and jetted accordingly

[Dark-Hawk]

hah okay I see. Are you going with stock pistons or forged ones? Cast pistons are not capable of holding too much, and not many cars are lucky enough to come with forged pistons stock. (I thank Nissan for givin me them hah)

[Tercel Drifter]

stock pistons. No there not forged:( it's an iron block with aluminum head. the engines been shown to take 10 psi daily on a turbo though

[Dark-Hawk]

heh just because some cars can do it doesn't mean others can. I'd be weary about running too big of a shot, approximately how big will the shot be you're running? I have seen plenty of KA's (240SX) take 13-15psi on stock internals on a daily basis where I've seen others have massive failure at all of ~7 psi. Aluminum head makes me weary too they warp quite easily; will you be using an OEM head gasket or something thicker?

[Tercel Drifter]

OEM spec gaskets. I figure they should hold. But yeah I see your point. i'm only doing a 35 shot to start.