Re: RE: FW: New dyno results, 4.7L Leach custom PCM

From: WMBARRET@aol.com
Date: Sat Oct 14 2000 - 20:35:57 EDT


The Company is Mike Leach Co. I had them custom program my PCM 2 weeks ago.
 

Matt Y2K-HEMI

In a message dated 10/14/00 8:22:42 PM Eastern Daylight Time,
rparenti@bellsouth.net writes:

<< Subj: RE: DML: RE: FW: New dyno results, 4.7L Leach custom PCM
 Date: 10/14/00 8:22:42 PM Eastern Daylight Time
 From: rparenti@bellsouth.net (Rob Parenti)
 Sender: owner-dakota-truck@BUFFNET.NET
 Reply-to: dakota-truck@buffnet.net
 To: dakota-truck@buffnet.net
 
 OK, this is purely third hand information. Sorry for it not being a
 definitive source. May or may not be interesting, and leaves a lot unsaid.
 Maybe some of you can fill in some of the blanks. My brother work for DC,
 (not in engine development), and this is what he has heard about the engine
 calibration chips:
>>
 Mopar's "performance" module is nothing more than a production controller
 with 2 degrees of spark advance added to all the data tables (we use
 flashable memory now instead of ROM chips). That's weak for $500! The
 'hot' cals used to be done by engineers here in their spare time and given
 to Mopar, we don't have the spare time anymore so they farmed out the work
 to some company in California. Both spark and fuel curves can be adjusted
 and can vary depending on what octane fuel you're targetting. The 4.7L
 doesn't have a knock sensor (not until 2002) so the production cal is very
 conservative. Not much spark advance, which needs lots of fuel to keep
 exhaust gas temps (EGT) down. Also, there is a fair amount of variation in
 the compression ratios of the engines. You can add a lot more spark
 advance on a 'low spectrum' engine (which actually flows better at the
 upper end). In general 10-15 degrees of spark advance can be added to the
 curves, another 10 for premium fuel. Then 8-10% of the fuel can be taken
 out because EGTs go down with spark advance (the flame front moves back
 upstream). Believe it or not, these hot cals will actually improve the
 fuel economy. NOx emissions go ballistic though because combustion
 efficiency improves. The EPA wouldn't allow that in production, they
 require emissions to be at stoichmetric (sp?), a compromise between
 hydrocarbons (un-burnt fuel) and oxides (burnt fuel). My expert says if
 you wanted to mill a little off your heads, with the new TB and intake and
 cal, you'd leave any 5.9L in the dust. Yet still have high reliability and
 better mileage.
So who is this company in California?
 - Rob
 



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