Grumpy

There seems to be alot of confusion about Smog Equipment.

First, in the US., it is a federal law that the emission control devises can not be modified or removed. While not generally enforced, that varies by state, and county. In some other countries, they have no or min emission laws. Heck up until last year leaded fuel was available in some GM marketplaces.

DIY chipping is at your own risk, and is for off road, and educational purposes.

Now about deleting stuff, and this is 3rd gen F Body specific:

Air pump, in open loop supplies air to the exhuast manifold to promote after burning of any fuel, and that also helps to warm up the O2 sensor. In closed loop it diverts air to the catalytic converter, to help with the chemical reaction therein. So at no time does it affect what the ecm sees O2 wise.
possible gains for it's removal, 5-8 HP, and that's at high rpm, in cruise or idle not real meaningful gains.

EGR:
You can get stung by this one.
If you mechanically remove it, then be absolutely sure the ecm is ignoring it. Flip the diagnostic flag, and set the enable temp to like 254. I personally never use the 255 as in some testing years ago it would sometimes add a hiccup to a running engine.
I have found no MPG increase, and while in theaory it should it never has for me. You will generate more NOX to a certain degree, but depending on the amount of overlap the cam has will effect that alot more. Engines self EGR, due to the overalp of the cam.
Exhuast back pressure can open an EGR valve. So if you have it on, and bypassed in code,, then you can have some strange problems.

PCV:
Only the misinformed will remove it. Period. What you might want to do is build a oil vapor air seperator to make sure no oil fumes enter the engine, oil in a combustion chamber will lead to detonation.

Charcoal Canister:
No HP lose or gain, by removing it.

Sealed fuel tank:
Can be a problem on high HP applications.

14.7 AFR:
Is for the catalytic converter, period.
It has nothing to do with what the engine wants. You can run slightly leaner at idle and cruise then that just fine. Touble is you need a Wide Band O2 sensor to know where you are, the oem O2 sensor is a swiching type, trying to read any thing other then richer or leaner then 14.7 is a market ploy, and followed by the *herd* type of tuner.

Thermostats:
The **HI** operating temps., while emission related, have little to do performance wise. Lower temp., gets you a slighty richer, more advance timing spec, and Seat of the Pants that feels good.
If in doubt PLEASE get a copy of SAE paper 960497.

O2 sensors:
Stick with AC, or GM. Other brands can have switching AFRs of 15.2, and have durability problems. Some have known problems, and have corrected them, but there are many junk ones still in the system.

DM91RS

Grumpy, your comment on oxy sensors being wide band are not has me wondering what are the sensors that come with the popular air-fuel ratio guages such as the Edelbrock? Are these useful and if they aren't what should one be using, a scanner?

Grumpy

The cheapest WB meter I've heard of costs $600.
the cyber, K+M, Edelrock, are all just slightly better then reading tea leafs.
Even if you use a WB, you still have to learn plug reading.
Ain't no easy answers.
If you look in the archives here I posted how EGT effects the O2 output voltage

mmaker

I don't care if my air pump stays on or comes off (although it would be a great weight saving). Whats bugging me is not being able to reach number 6 and 8 spark plugs (not to mention the leaking coolant switch in between) for all the AIR diverter crap on top and the headers preventing me from access below. The headers are staying so the diverter paraphenalia (sp?) have to go!

The oil vapour separator is a great idea and i read about it before - i guess a pcv valve would stop air going back into the manifold. I just have breathers on the valve covers but i have a feeling they are clogged now - so the oil vapor is probably being forced back in - not good with these high summer temps.

I have a buddy building his own sensor and lcd gauges with mass marketing intentions. He is in conversation with a guy whose whole schooling and career has been soley on the O2 sensor. He (the latter) was recently hired by the Chinese gov't to work on this for them as they want to measure about 16 different gases (from an automobile???). Anyways - my buddy says that unless you have the $4,000 Huroshi? or the $10,000 one made by ? or the recent one Honda just put out - all other O2 sensors (including wide band - i have never seen one) are just like on off switches - just a guessing game - they are NOT ACCURATE!

What a racket - pretty led lights and all!

blue86iroc

iTrader: (2)

Bringing back this post from years ago...

My friend and I both have 180* thermostats in our cars and the engines stay very cold -- to the point that both of us are wasting gas because they're running so rich. I was thinking of putting a stock 192* back in, because I've heard it's best to run the engine at the temperature that it was designed to run.

If I can tune the 180* stat to take advantage of its benefits, is it any better than using a 192* and tuning that accordingly?

Grumpy

Lots of variables, and it will vary some car to car.
If you go completely through the calibration, and do it all 100% CORRECTLY, you'll make as much HP on the street at 195 as at even 160.

Swapping thermostats to make HP is a very Low Resolution way of tuning a car. And not always effective.

blue86iroc

iTrader: (2)

Thanks Grumpy, that's EXACTLY what I wanted to hear. I feel better running the engine the way it was designed, rather than cutting corners and possibly hurting the potential of something else. In goes the 195 .

IrocZonNos

Could you post pics and supply details on how and what parts to remove when eliminating the AIR pump.

Thanks in advance.

91L98Z28

Wow, this is a post from a long time ago!

I was wondering if the quoted section above is still accurate. Tim has done some work in determining that there is a (if memory serves) 100mV offset to the o2 values when AIR is enabled, at least for AUJP.

??