++ ATOT official NEF thread part IV ++

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MotF Bane

No Lifer
Dec 22, 2006
60,801
10
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The fuck is that?

OBDII is On Board Diagnostics, version II. We can really thank those fuckheads in California for it, coming up with their weird ideas about emissions, then mandating things like CARB (emissions restrictions in CA only), then mandating OBDII on all cars sold there. The feds heard that, decided it was a great idea, and made it federal - everything '96 and up needed to have OBDII.

It lets you, or the inspection agencies, plug in big scanners that can check tons of sensors in the car. It's not for black box crash data, it's for emissions and safety checks. Unfortunately, it has programmed spec ranges for each model of car, so if you do an engine swap, it'll throw all sorts of flags, as the sensors won't match up, the readings that show will be way outside of parameter, et cetera.

The government has failed to provide exception ranges for engine swaps and other enthusiast mods.
 

MotF Bane

No Lifer
Dec 22, 2006
60,801
10
0
Seems some states are more permissive, some states are absolute Nazis.

Since my parents have two houses in two states, I could register to whichever state is better for me - which would probably be NH.
 

MotF Bane

No Lifer
Dec 22, 2006
60,801
10
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I'm seeing a few indicators that you can swap involving OBDII, but only IF the state permits engine swaps, and even then, it seems that it will need to pass OBDI (no typo) emissions standards, and that the motor must be newer AND at least as emissions-clean as its predecessors.

I don't know if a V8 can be as emissions-clean as an I4 of a third the displacement. Something else to understand tomorrow.
 

MotF Bane

No Lifer
Dec 22, 2006
60,801
10
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"This 2004 Chevrolet Corvette Z06 yields a whopping 972 hp and a monstrous 1057 lbs of torque from its twin turbo LS6 engine on premium pump fuel "

LOLOLOLOL.
 

MotF Bane

No Lifer
Dec 22, 2006
60,801
10
0
No, bad Bane. Focus. Engine compression ratios versus boost. Turbocharger sizing as a function of boost.
 

MotF Bane

No Lifer
Dec 22, 2006
60,801
10
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The optimum air-fuel ratio is generally around 14.7... which is suspiciously similar to a measure for atmospheric pressure.
 

MotF Bane

No Lifer
Dec 22, 2006
60,801
10
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So forced induction forces more air in... which would be a lean AFR by default. So then you need more fuel. So then you have lots of fuel and lots of air crammed into a hot tiny space that shrinks. Thus, if not done right, it explodes spontaneously. Higher compression ratios, per the gas law, will exacerbate this effect.
 

MotF Bane

No Lifer
Dec 22, 2006
60,801
10
0
Thus, a low compression ratio motor is better for forced induction!

Unfortunately, most factory cars are going for higher compression ratios.