Lean Cruise...legal in the USA? Possible!

[eficalibrator]

Like Chris says, the name of the game is reducing the losses in the system. Any time the throttle is closed, part of the engine's work goes into drawing a vacuum in the intake manifold instead of pushing the car down the road. We call this "pumping loss." Things like lean burn (stratified charge) and EGR force the throttle open more, reducing pumping losses. 1-2mpg is considered a "good" return for this on most applications. Don't look for a magic bullet here that will unlock 10mpg or anything.

If you're looking for fuel economy, you can also look at the trans calibration. Locking the convertor reduces some of the losses there as well. Making sure the convertor stays locked at cruise and most tip-ins will help. It can help to make the unlock points set lower than the downshift points at anything short of WOT, but drivability may be slightly reduced.

[EC_Tune]

Interesting: Just read that the latest "DuraMax" will now have a throttle!

Diesels with throttles! What's the world coming to....

[eficalibrator]

The diesels are starting to use throttles so that they can employ larger quantities of EGR to reduce NOx emissions. They need to create a pressure differential (vacuum) for the EGR to actually flow. Adding a throttle does this pretty easily.

[Bill@HPTuners]

So when are you doing an HP Tuners based class near Jersey Greg? hehe

[truckmann]

When is you book due to be released? I need all the learning material I can get!

[eficalibrator]

I posted a class in Long Island in the other thread. April 14-15th. We will cover a wide range of systems in that class, and I don't have a problem fielding HPT questions then. The book should be available in april or may. The quickest way to get it is to order directly through my publisher. I have a link in my sig.

[domestic rice]

Few things I was wondering about this

Why can the 04 goat have the lean cruise option but the other years cant?

How would HPT be any more responsable for allowing this to be enabled?

If everyone who buys this program is messing with the VE, PE, DFCO, COT, OLSD all those would effect what was tested by the govt. as well. Hell most people pull the cats and run LT's, it is not the vender/makers fault, it then becomes the responsability of the person using it.

[EC_Tune]

How would HPT be any more responsable for allowing this to be enabled?

If they allow access to this code they can be liable. If they don't allow access, no liability.

As to the 04 GTO, it's an export Holden with LH drive. Holdens have lean cruise.

[horist]

Interesting: Just read that the latest "DuraMax" will now have a throttle!

Diesels with throttles! What's the world coming to....

what did they use before this? (I know nothing about diesels)

[eficalibrator]

The "traditional" method of torque control (throttling) in a Diesel is limitation of fuel delivery. It doesn't hurt the Diesel to run lean, in fact they run REALLY lean compared to stoich. Since the fuel contains the energy to be released, limiting total fuel delivery limits total torque/power output. This is also why adding fuel to a diesel generally makes more torque. (At least until it gets too hot or the soot is excessive)

[n0dih]

IIRC didn't the TPI lean cruise work by dropping off into an open loop mode while at cruise and with EGR on if certain conditions were met? So the VE tables or open loop AFR tables would then be able to do a reasonably precise lean cruise mode. You could then configure how LC Mode would control it.

It seems to me why can we allow lean cruise within the framework of reasonable emissions if there is sufficient EGR flow to keep combustion chamber temps under control.

Question: Everyone says lean cruise is "illegal". Can someone PLEASE post official documentation showing this? I have searched EPA's websites on emissions laws and can find nothing that states this. It strikes me as a paranoia that has been left unchecked and allowed to grow. Is it? I don't see how lean cruise enabled would be making emissions any worse than any other tuning that we can do, so why the paranoia on it?

[S2H]

IIRC didn't the TPI lean cruise work by dropping off into an open loop mode while at cruise and with EGR on if certain conditions were met? So the VE tables or open loop AFR tables would then be able to do a reasonably precise lean cruise mode. You could then configure how LC Mode would control it.

It seems to me why can we allow lean cruise within the framework of reasonable emissions if there is sufficient EGR flow to keep combustion chamber temps under control.

Question: Everyone says lean cruise is "illegal". Can someone PLEASE post official documentation showing this? I have searched EPA's websites on emissions laws and can find nothing that states this. It strikes me as a paranoia that has been left unchecked and allowed to grow. Is it? I don't see how lean cruise enabled would be making emissions any worse than any other tuning that we can do, so why the paranoia on it?

try this


http://www.epa.gov/EPA-AIR/2000/Febr...ay-10/a19d.htm

I didnt do a super great read through..just sort of skimmed it for info

its not technically an issue with the principle of lean cruise...its about emissions...and you cant control emmissions properly when you are using lean cruise...
EPA actually terms it "Lean-on-cruise"... that will make your searching much easier

and also its an issue with lean cruise being used for "off road use"...if you can show how lean cruise will help you while "Racing" then maybe HPT will support your cause...but HPT is for "Off Road Use" and legally you cant modify the PCM in any way shape or form without permission from the EPA unless its for "Off Raod Use"
companies that have 50 state legal(USA) superchargers/Turbo Chargers and power adders have gone thru extensive testing and have spent huge amounts of money to please the EPA..all of these companies that provide products usually have a calibration of their own that they sell along with the product so that they show their effort to please the EPA standards..
can you buy them without their calibrations...yes...but they all own their own versions that they can sell you.