pressure

[Kahn Souphanousinphone]

what would be some problems with having too much air pressure from a turbo/supercharger?
as long as the fuel pump/EFI can deliver, and the pressure isn't outragious, I dont really foresee any problems developing.

What do you use to determine the right pressure?

[txgti]

1. Head GAskets. THEy can only hold so much.

2. Rings. THey as well can only hold so much.

3. Temperatures. With Pressure, somes heat, and with heat comes melting internals.

[Kahn Souphanousinphone]

on #3, i know all about compression causing heat, having been a hvac/r technician and I can guarantee you that even on a turbo without a cooler the heat generated would be insignificant compared to combustion (given coolant system is working normally as it should).

1 & 2, the pressure from combustion is much more than any supercharger/turbo is capable of.

I'm not trying to be argumentative, but just trying to learn.

[Pull_T]

Originally posted by steve2002


1 & 2, the pressure from combustion is much more than any supercharger/turbo is capable of.



True, but the higher you make the effective compression ratio from additional airflow, the pressure from the combustion increases, giving you 1, 2 and 3 that Marc outlined.




Obviously, without the combustion process, compressed air alone will nat harm a motor.

[Kahn Souphanousinphone]

sounds like, from better combustion (more complete fuel ignition) the heat goes up.

that brings me to another question i've had for a long time: why would a turbo/s.c. affect smog test? i've read where people with turbos struggle to pass tests. the main thing they're looking for in a smog test is incomplete combustion (why we have cat. conv.'s) but with forced induction I would see no reason for them (cat. conv.'s or failing smog tests). :confused:

[Pull_T]

Originally posted by steve2002
sounds like, from better combustion (more complete fuel ignition) the heat goes up.

that brings me to another question i've had for a long time: why would a turbo/s.c. affect smog test? i've read where people with turbos struggle to pass tests. the main thing they're looking for in a smog test is incomplete combustion (why we have cat. conv.'s) but with forced induction I would see no reason for them (cat. conv.'s or failing smog tests). :confused:

Well, it's more the fact there is more air and more fuel in the chamber so heat goes up, the efficiency of the burn is another matter.

Combustion creates exhaust by-products, whether the combustion is "complete" or not. The reason FI applications often fail is that they are tuned to be more rich (lower air/fuel ratio) and that can make the sniffer fail it.

[Kahn Souphanousinphone]

the main thing they look for is unburnt fuel, which is what the cat. conv.'s fix.

basically, i'm trying to see if my theory is true: without fuel supply upgrades, a s.c./turbo would make cat. conv.'s unnecessary.

that brings another question: how much performance gain will you get without larger injectors/f.p./ect. but only by charging air-------


(yes, i have too much time on my hands, and i cant pick on the mentalmidgets at the 'other' site cus i'm banned from there):p

[Pull_T]

Originally posted by steve2002


basically, i'm trying to see if my theory is true: without fuel supply upgrades, a s.c./turbo would make cat. conv.'s unnecessary.


I would say that's true.

Stuff air in the motor without extra fuel and you'll have bigger fish to fry than emmisions, though I would wager with a hole in a couple pistons, a lot of unburnt fiel would get through.

[Turbo]

Originally posted by steve2002
on #3, i know all about compression causing heat, having been a hvac/r technician and I can guarantee you that even on a turbo without a cooler the heat generated would be insignificant compared to combustion (given coolant system is working normally as it should).

1 & 2, the pressure from combustion is much more than any supercharger/turbo is capable of.

I'm not trying to be argumentative, but just trying to learn.

if your at stangbang come touch my intake, ill have the ice ready for ya, also turbo/sc cars run rich at lower rpms bc they r always set up a lil fat, id rather have too much fuel than not enough, its cheaper that way in the end, thats y my 4.1L motor is in pieces, it leaned out under boost and the head gasket decided to take a walk

[txgti]

Ideal air / fuel as far as an emissions perspective is concerned.. is roughly 14.7 to 1, right?

IF you try to run that lean on a boosted motor.. you're going to pop a head gasket, or melt a piston. Plain and simple. If it holds, then over tile.. you'll be pissing oil out of your exhaust because the rings are shot.

BElieve me or don't.. doesn't bother me.

FWIW.. Ideal air/fuel on a boosted motor is roughly 11.5 to 1.

[Kahn Souphanousinphone]

Originally posted by txgti
\

BElieve me or don't.. doesn't bother me.
\. i was interested in learning about the reasons behind the explanations, not making this a cyber battle of wits.

i'm the type to ask why, not for cyber public opinion polls on what people 'believe'.

[txgti]

Originally posted by steve2002
i was interested in learning about the reasons behind the explanations, not making this a cyber battle of wits.

i'm the type to ask why, not for cyber public opinion polls on what people 'believe'.

Roger that.. how's this? Answer your questions?

a big chunk ofit is as the intake charge temperature rises.. it makes the air fuel mixture that much hotter,a nd that much more likely to detonate before that piston is at the top of it's stroke. tHat would be pinging, or predetonation... detonation for short.

THAT's what kills pistons, and THAT's why the temperature created by the compression of the air is dangerous.

AS for head gaskets and rings.. it's strictly about the added compression inside the cylinder. They're going to give out eventually.

[Kahn Souphanousinphone]

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