compression ratio vs boost psi

[FastFwd]

Well your right, there are many variable. Motor condition, Tune, etc etc but it depends on every turbo setup your running.

But it didnt bother me that i blew my motor anyways cos i knew "ahh if i blow it im gonna be rebuilding the motor anyways"

[nigs]

lol, sounds like you'd love a rotary.

[Q_ball]

Luck is like hoping it won't blow up. If thats the case why boost it if your going to worry all the time.

There are heaps of variables, but luck is not a factor at all.

Touche... its all in the tune baby... all in the tune.

[Lukezen27]

I'm running high comp I'd say after two head shaves with 11PSI on stock internals

http://fjdistributors.com/index.php now make custom rods to raise the comp close to stock with low comp forged pistons

[spardikis]

Luck is like hoping it won't blow up. If thats the case why boost it if your going to worry all the time.

There are heaps of variables, but luck is not a factor at all.

he just said it for me...

keep compression on the higher side. better response, less lag, less boost for same power.

good luck

[A-man]

yeh u cant build a highly modified car and not expect something to go wrong... if u r worried and if u dont wana fix stuff then go buy a xbox and forza motorsport and sell ur car and buy a jazz or something...

i think tune has alot to do with it aswell as maintance...

[votek]

keep compression on the higher side. better response, less lag, less boost for same power.


is that the same results for the same turbo?

[dsp26]

http://www.ozhonda.com/forum/showthr...pression+ratio

[DLO01]

keep compression on the higher side. better response, less lag, less boost for same power.


is that the same results for the same turbo?

Given the same engine specs. You will get more power out of a larger, higher flowing turbo. Same with boost pressure. At the same pressure (10psi or whatever), you get more out of a larger, higher flowing turbo. Pressure and Flow are 2 different things.

[Limbo]

all comes down to the fuel and tuning.
The higher compression needs better fuel and more accurate tuning, or it can detonate easliy. Its one of the drawbacks of hi-comp, that i don't think everyone explains

On a lower comp car there is less issue when it comes to fuel & detonation.

True you will make slightly less power & lag abit more, but people generally up boost to compensate.

[anjin]

I did an exercise on engine cycles a while ago, and one of the things that really made sense was the interelationship between compression ratio (however achieved) and timing. The maximum pressure developed in the cylinder should occur about 14/15 degrees after tdc - at that point the force developed will force the piston and rod around the crankshaft. Any earlier and you are trying to force the rod through the crankshaft. Any later and you are past the optimum leverage point as the mixture expands and the piston accelerates away down the bore.
Now in order to get maximum pressure at that point you have to start the fuel air mixture burning much earlier -before tdc. That is why you have a static ignition point at say 16 degrees BTDC and it advances to even earlier at higher revolutions - the fuel-air mixture burns at the same pace at 1000 prm as 8000 prm.
But it burns faster at higher compression ratios. So to get maximum cylinder pressure at 14 degrees atdc with high compression ratios than stock you actually have to retard the timing.
That is where a lot of the tuning skill for engine longevity comes in when you boost engines.

[FastFwd]

I did an exercise on engine cycles a while ago, and one of the things that really made sense was the interelationship between compression ratio (however achieved) and timing. The maximum pressure developed in the cylinder should occur about 14/15 degrees after tdc - at that point the force developed will force the piston and rod around the crankshaft. Any earlier and you are trying to force the rod through the crankshaft. Any later and you are past the optimum leverage point as the mixture expands and the piston accelerates away down the bore.
Now in order to get maximum pressure at that point you have to start the fuel air mixture burning much earlier -before tdc. That is why you have a static ignition point at say 16 degrees BTDC and it advances to even earlier at higher revolutions - the fuel-air mixture burns at the same pace at 1000 prm as 8000 prm.
But it burns faster at higher compression ratios. So to get maximum cylinder pressure at 14 degrees atdc with high compression ratios than stock you actually have to retard the timing.
That is where a lot of the tuning skill for engine longevity comes in when you boost engines.

NS dude?

where u learn that man u sound fairly knowledgeable.