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Discussion Starter #1
bounce OK, I have been running my 4bta for about a year now. It had enough power to suit me but no xtra. Good mileage but EGT was to high. Started playing with timing about a month ago, best power at highway speed cost me some boost. So I purchased a 12cm turbine housing. Brought boost up some, egt down some. Called the shop back up and ordered compressor wheel and housing. Installation produced no results.:confused: I was convinced that I had a big preessure drop after JWAC aftercooler. Today while I was making preparations to get a pre-jwac boost reading, I just happened to glance into the jwac and the entire top surface of the core was covered with a black cottony-fibrous material. My engine was breathing through a small 1.5 inch hole in this stuff!
Long story short, After cleaning I went from 14psi boost to 25psi boost that comes on early. Egt came down 200*! Definately gathers up mph's faster than the 400 4 barrel that was in it. Cool down at shutdown is nearly non existant . All that I can figure is that there was an air filter failure before I got the van and I missed it during installation. Extremely happy now and high fives all around!bounce
Carl

1979 F-250 crew cab 4 x 4
4 bta with modified H1C
Cold air intake
ZF S-42 5 speed
Borg Warner 1356 x-case
Dana 60 rear
Dana 44 front
3.55 gears
255/85R16 tires (33.5x10.5)
Hydroboost steering and brakes
Custom 40 gal. fuel tank
Much more later
 

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That's excellent news.

Nothing like finding the source of a long bad headache, and fixing it easily.:dustin:
 

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I love happy endings :)
 

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Good to hear.......I hate all those little things that have such profound outcomes
 

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Yeah, that's great news! But, I'm a bit confused: you say a 12cm exhaust LOWERED EGT's? That should have raised EGT's from the stock 16cm exhaust, not lower. Any good explanations out there guys?
 

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Very cool Carl..!
 

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Discussion Starter #9
Keep in mind Jimmie, that I had a pre-existing severe air restriction between turbo and manifold so I dont have true boost or egt numbers before I modified my turbo. This restriction probably also caused the high egt numbers that i had due to compressor wheel strain transfering to the turbine. After I cleared the restriction, max boost went up 11psi. :D
Carl
 

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what kind of difference in mpg are you getting?
 
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