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Old 01-13-2008, 05:36 AM   #5 (permalink)
EcoModding Lurker
Join Date: Jan 2008
Posts: 15

Fix Me - '71 Datsun 240Z

BlueStreak - '02 Bianchi Bianchi Eros
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If it really does just dilute the exhaust as opposed to oxidizing CO and HC's...then its just a sham and I should go ahead and remove it. Cats actually work since they have the catylyst plates that convert CO and HC's at the chemical level...the better way to go.


I've played with the carbs on the engine quite a bit...and I also have a chart that give tuning specs (in terms of turns from closed of the main fuel jet) as a function of altitude and I have some baseline data that I can work from without leaning them out so much that it detonates. I also have a colortune device that I use when adjusting the carburetors.

As far as reducing HC's with an air injection/cat converter combo...I would be willing to bet that the cat was responsible for most of the actual reduction in emissions. If I did get a cat...I would use one of those high flow cats meant for modern high performance make absolutely sure restriction is minimized.

Did you mean to say 6-2-1 headers (the L24 is an I6, not an I4). Actually, the stock manifold is a 6-2-1 design that works well with the engines firing order. The OEM manifold is actually a fairly good design...dyno tests have shown it to be comparable performance wise to many of the available aftermarket headers...using a 2.5" exhaust from the manifold back however has been proven to increase both power and gas mileage. I think the ultimate set-up would be an equal length 6-1 header with a 2.5" exhaust (equal length header combined with free flow exhaust is hard to beat).

I actually already have one of the tallest geared diffs (3.36:1)...but I could convert to a 5-speed from a 280Z or 280ZX one of these days, which would do the same thing.

Coyote X:

Even if I made the pump electric, it would still cause engine load through the alternator. Besides that, I almost never have my engine under 1500 RPM...because I do very little idling and cruising at that RPM means lugging the engine...I think its better to just remove the pump and air injection altogether and use other methods for emissions reduction.

As far as the visual inspection goes...I don't need one for 4 years. That and I go to the pre-1982 emissions place...which is kind of a hole in the wall Mickey Mouse operation anyways. The old guy who runs the place probably wouldn't know or care that the car is supposed to have air injection as long as the tailpipe emissions are within specs...I don't even know why I'm worried about the visual part.
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