off subject - chevy 350ci 5.7 emissions question

jgra1 · Unread post by **jgra1** » 22 Feb 2008, 11:57

hi all..

I was wondering whether I could remove any emmision components from this engine.. based partially on the fact that some of us on FCF remove EGR valves and so on..

I realise there is a moral issue to ponder... but I have definately heard of these controls strangling engines, when our emission laws are less stringent than either 49 states, or Cailfornia..

The engine needs to make all the power it can, in the application it's being used for..

There is an air pump, which forces fresh air into the exhaust valve area, (Air Injector Reactor) - to help complete the burning process post combustion.. this may take a few horses..

there is egr present, although this is just vacumn operated, do vacumns 'cost' power?

other systems are in place too...

any thoughts ? am i on a bad road to being [more] of a nuisance who should leave things as Chevrolet intended

John

Clogzz · Unread post by **Clogzz** » 22 Feb 2008, 15:20

Not too sure, but think that General Motors pump air into the exhaust to dilute it and reduce the emission ‘readings’.
Nonsensical, but legal.

Vacuum doesn’t cost power, all adjustments affecting it are to maximise the vacuum, meaning deeper vacuum … lower pressure.
The ideal way to adjust the idle mixture is with a vacuum gauge, tweaking for maximum vacuum, resulting in the steadiest idle, and demonstrating the gain in efficiency by actually increasing the idling speed, that can then be reduced with the idle speed screw, which is acting on the throttle opening.

You’re not on a bad road; you’re using it for a purpose other than plodding along American roads.

Unread post by **CitroJim** » 22 Feb 2008, 17:39

Not quite, the AIR system injects oxygen-rich air into the exhaust so that excess hydrocarbons and CO can be burned in the headers

This is how the emissions are reduced

They also retard the ignition a bit to help things along as well.

The mixture is purposely richened a bit to ensure this secondary combustion takes place. All tuning books recommend the AIR system is removed and the injector bosses in the exhaust mainfold ground back flush so as not to impede gas flow. One book I have goes on to say about leaving all the emissions stuff in place and apparantly operational but with vital and invisible bits blocked off.

Disable the EGR valve too. They do terrible things on a petrol engine

Also, if you have a heated inllet mainifold, disable this too so the intake charge is cooler.

Then, you'll find you can perhaps weaken off the mixture a bit and advance the ignition a tad.

Legally, in this country, if the car or engine is pre '92 your limits will be 3.5% CO at natural idle which is easy enough to achieve, HCs I cannot quite recally but 200ppm seems to ring a bell.

If the vehicle is post '92 you'll need a cat and meet CAT emissions.

Hope that helps John.

MikeT · Unread post by **MikeT** » 22 Feb 2008, 19:45

I'm intriqued now, what "application" is planned for this powerhouse?

ACTIVE8 · Unread post by **ACTIVE8** » 22 Feb 2008, 22:30

MikeT wrote:I'm intriqued now, what "application" is planned for this powerhouse?

Me too !

jgra1 · Unread post by **jgra1** » 22 Feb 2008, 23:52

thanks all

I so so wish I had a fire breathing dragon of a mid engined activa or something !

but no

all i have is an extended chevy chassis and a large RV on the back

I want to pop around europe and need to climb hills

5 tons GVW !..

may come back with more questions as US engines leave me baffled!...

1985 is year of manu..

John

Unread post by **CitroJim** » 23 Feb 2008, 19:59

Hi John,

Your reasons make great sense

A very good couple of books which are very Yank V8 orientated are "Four-Stroke Performace Tuning" and "Modern Engine Tuning" both by A. Graham Bell (no, not that one!) and published by those who publish the BoL (Haynes).

These two books, between them, go into every aspect of tuning for performance and economy and use Yank and Aussie V8s (including the Chev) almost exclusively as examples.

The books are a very enjoyable, easy read and don't get too technical anywhere.

ACTIVE8 · Unread post by **ACTIVE8** » 24 Feb 2008, 11:07

So it's not a day van, but is it an "A" class?

jgra1 · Unread post by **jgra1** » 24 Feb 2008, 13:05

thank Jim

active, it's a C class.. coach build cab overhead bed ... A classes are specific design RV's with the cab an intgral part of unit..

Basically, this is a day van conversion to an RV by a coachbuilder..

looks like http://cgi.ebay.com/ebaymotors/RV-Jayco ... enameZWD2V

although mine is much older, fibreglass sides not aloominum

John

jgra1 · Unread post by **jgra1** » 25 Feb 2008, 14:54

"Modern Engine Tuning"

brought on ebay for about £17

ACTIVE8 · Unread post by **ACTIVE8** » 25 Feb 2008, 22:40

jgra1 wrote:thank Jim

active, it's a C class.. coach build cab overhead bed ... A classes are specific design RV's with the cab an intgral part of unit..

Basically, this is a day van conversion to an RV by a coachbuilder..

looks like http://cgi.ebay.com/ebaymotors/RV-Jayco ... enameZWD2V

although mine is much older, fibreglass sides not aloominum

John

Yes, I thought as much due to the GVW that it probably wasn't an "A" class.

jgra1 · Unread post by **jgra1** » 25 Feb 2008, 23:47

yep

I did look at an A class but parking restrictions forbade it..

at 23 ' it's a tiddler.. still , very wide, 2.5m! lots of work needed I think