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Old 04-12-2013, 05:11 PM   #140 (permalink)
hackish
Calibration Engineer
 
Join Date: Jan 2010
Location: Canada
Posts: 86

Subie - '00 Subaru Impreza STi JDM
90 day: 22.49 mpg (US)
Thanks: 1
Thanked 18 Times in 14 Posts
Quote:
Originally Posted by turbovr41991 View Post
If I recall correctly my friends 91 corvette ZR1 had the LT5 engine in it which was not a push rod engine. I thought that was one of the major differences between it and the LT1, but I could be mistaken. It had the “1st to 4th” servo in it. This servo was even on the late 90’s and 2000’s corvettes with the LS1. We should not be talking about 60’s technology here… We are talking about the same era in which they made lean burn so regulated it was no longer a viable option to be produced.
The old ZR1's had a lotus engine in them. Effectively it was a race engine and racing and emissions or fuel economy seldom go hand in hand. When you look at the GM V8's I wouldn't exactly call their technology modern.

Quote:
Originally Posted by turbovr41991 View Post
I would think this fact is highly skewed. Perhaps you are getting your pulse and gliding data from a vehicle that is horribly inefficient with a hideous drag coefficient… Most cars show much higher gains from this without doubling emissions... Not to mention, you can regain speed under low engine load thus further lowing emissions as well. I believe a stock Prius showed this best getting 117 mpg! Over 100%+ gain over EPA. I am not sure on the emissions on that test, but before you are going after people trying to conserve resources, I suggest you try to enlighten the masses who romp and stop to get from point A to point be…
The test data is in fact skewed because my 5 gas analyzer wouldn't read that high. It would peg at max until midway through the pulse when the cats lit off again. When I have time I'll see about getting a new analyzer (they are about $5 grand) and put some more time into collecting data.

Ideas promoted in threads did things like advance timing (NOX goes through the roof) or special cutoff switches to turn the engine off on their glide (COX & NOX goes through the roof until the cat gets back up to temp). All of that to say what feels like you're saving the environment may in fact not be.

In your corvette example is a minority. You need to consider averages to have the most significant gain for effort spent. This is why they instituted emissions offsets for carmakers. 1 type of dirty car has a smaller footprint with 1000 models sold than a small improvement on the most common vehicle.

My line of work is driven by the cost of fuel. If fuel were cheap it would be difficult to cost justify having your fleet modified for fuel economy. Your gas stompers and stoplight racers could be encouraged in similar ways.

-Michael
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