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Discussion Starter · #1 ·
when you turbocharge a car, aren't you basically raising the compression inside the cylinder? i mean..isnt it the same as raising the compression with the pistons? it shouldnt be that simple but id like someone to explain...
 

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Discussion Starter · #4 ·
ive already read everything on turbos and know how they work, but what it all comes down to is what happens at the top of that pistons, THATS where the horsepower is made, the more pressure its under, the more explosive(hence higher CR=more HP) lets say an H22A4 10:1 static running 7 psi(12.2:1 total) would you get more horsepower by just running 12.6:1 pistons? plus the turbo is heating the air up before it crams it in! sure things can be done to help this, but the air will never be as gold as if its taken right out of the air(cept maybe a co2 intercooler). what it comes down to by the turbo forcing that air in is raising the compression! once the mixture comes into the cylinder head, its always the same...
 

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nope turbos dont increase CR, that can only be done by the piston. what a turbo does is increase the pressure but not CR. for example someone driving at sea level would have more pressure than someone driving at 1,000 feet but their CR are still the same. see where im gettin at, CR is the relationship between how much air there is in the cyclinder at BDC and TDC.
 

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its better to have lower comperssion that higher compression on a turbo correct or am i wrong... i thought higher compression is better on a na car
 

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Discussion Starter · #7 ·
thats correct, but why do you think its like that? because turbocharging adds compression! why do you think non turbo cars that run regular have to switch to premium when they run turbo? to reduce the risk of detonation!(the fuel exploding before the spark CAUSED by high compression) your exactly right, if you run 10.0:1 pistons and turbocharge it, the compression with the turbo is too great unless you turn down the psi! and it doesnt matter if air is "forced" into an engine or sucked, cause inside the cylinder head the valves close, and whatever pressure that mixture is under will determine your horsepower. trust my judgement here..or find a reaaal god reason to prove me wrong. ive studied 4 cycle engines(2 cycle also) so good luck! rotary 4 cycles also ;D
 

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alright. compression ratio is.....the volume of air that gets sucked in gets compressed to a certain ratio....and the final volume at TDC is the ratio.

so if a piston sucks air in and its the lowest part....thats the max volume in the cylinder...on a 10:1 compression ratio engine....when the piston goes to compress that air and fuel it just brought in...it compresses it to 1/10 the initial volume.

Now depending on the initial amount of air molecules and fuel that were sucked in, in the beginning of the stroke(bottum of stroke), depends on the compression inside the cylinder. Compression is what makes power....thats why people put higher compression pistons in a car....but adding more compression(either by adding higher cp pistons or turbo) will increase the chance for preignition.....exploding before the spark plug ignites.

This occurs because more air is getting sucked in or the air is getting compressed further......now when the air gets compressed the air molecules start moving into smaller and smaller area with not much time to diffuse. This creates lots and lots of heat since air molecules and fuel are getting jammed into a smaller and smaller area with no time to go to a steady state. This heat may reach a certain temp where the gas/fuel mixture explodes....which may be on the up stroke of the piston...causing preigntion.

a turbo forces air molecules in, more Oxygen molecules means more fuel can be burned...as goes for nitrous, N20....(nitrogen acting as a buffer) these increase piston cylinder pressure which creates larger explosions, resulting in more HP. BUT higher octane gas will be needed.

The octane rating corresponds to the temp at which it burns at...higher octane gas resists burning/exploding till a higher temp.


a turbo creates a lot of heat cause 1, your jamming more air into the cylinder...like I said before...more air molecules are bouncing around in the cylinder when getting compressed into a smaller volume, with no time to diffuse....which creates tons of heat.

and also its hot because your running exhaust through the turbine.....this exhaust alone is hot as fucking shit...and its hotter cause you keep jamming more air into a cylinder thats already making more heat from the turbo itself....then your jamming hotter air in cause the turbo is heating the incoming air.

intercooler:) cools the air coming in.

the name of the game is air/fuel in....exhaust out as fast as possible........and more Oxygen means more fuel...which means more power.
 
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