treyZ28

That is just silly. Think about this for a minute. Higher compression doesn't warrant higher rpm. RPM is a killer- sure. What does that have to do with compression though?
The fact that you make a bit more power would actually make it easier on the engine- maybe preventing the need for downshifting and higher rpms at times.

The compression ratio is irrelivant- its the physical cylinder pressure that will do any kind of damage. I've never heard of compression, in such small magnitudes, accelerating wear to a measuable quantitiy.

higher compression engines are typically higher performance engines. Untuned, knocking etc caused by improper setups can cause premature failure. This might be where the misconception comes into play.

jrp

iTrader: (16)

tr230 w/ bolt ons vs same setup w/ the addition of heads. dont remember the brand.

SouthFL.02.SS

I've always overlooked the TR230's great tq curve.

BlackHawk T/A

iTrader: (3)

PERFECT jrp, that's exactly what I needed. Answered the last few of my questions.

cowboysfan

talking about raising compression that can cause accellerated wear, does'nt installing a higher dur/lift cam increase compression in a diffrerent way then milling heads but, same diffirent increased compression? explain somebody!


fuerzaws6

ringram

Graph is interesting, though it looks like the first run was too lean anyway. Some of the power pick up is from the more optimal afr IMHO

BlackZCamaro

iTrader: (1)

I never said higher compression warrants higher RPM's, but in many 'high performance' engines, the cam that will produce your best power is going to be spun up higher than, say, a decent street cam.

No, the fact that you are creating more power doesen't mean you are going to drive it easier, or that it is going to be easier to drive. If you're just adding power to go the same speed using only part throttle instead of WOT, then youre wasting your time and money. Think about it, the only reason we mod our cars is to go -that- much faster, not to go as fast with half the effort.

Final cylinder pressure is determined by the amount of air let in the intake valve (by the cam profile) and the static CR of the motor. Wouldn't bumping up either of these factors make a difference, especially if your cam creates a lot of cylinder pressure? That would, in turn, create more friction between your piston rings and cylinder walls. More pressure = more wear = Less mileage.

High performance doesen't neccessarily mean high durability. I am just telling BlackHawk what I have been told by numerous, reputable shops and companies over and over the past week concerning the numerous CR's in today's cyliner heads.

treyZ28

how is that relivant to compression?
In building an engine- you always shoot for the most compression you can attain with your fuel/spark/emissions requirements. High or low performance.
But I most street/strip cars spend a GREAT amount of time at non-WOT conditions.

It isn't going to create more wear on the piston rings, not enough to matter anyway.
More compression = more power for the same amount of air and fuel in.
So if you need 100units of fuel to make enough power to cruise at 90mph, now you need 90 units of fuel.
if you need 500 units of fuel to accelerate at a given rate from a light, now you need 450.
usually, it doesn't. infact, its almost always the opposite.

I'm just telling him he'll be just fine with a high compression engine and it will make more power and get better gas milage. Compression is like free power in a sense. Obviously, too much compression means not enough spark timing. There is a point where more compression will create less power because timing is getting so retarded. That is a fine line with every engine but I highly doubt that is the case.

I dont understand why the machine shop says "with todays heads." "todays heads" blow away, in terms of combustion chambers, anything from the "old days." Better combustion chamber allows for more retarding of spark timing (or makes more peak torque with less timing) than "old heads." This means you can run more compression.

DaleMX

iTrader: (4)

I'm running 10.9:1 on a TR230 and 93 octane without problems. Pull's like no tommorow above 3000 all the way to 6800.