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Junior Member
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Discussion Starter #1
I'm new to this board and could use a little help. I have an 89 4mg, I was not sure if anyone had been in the fuel screws so I set them as per another guys advice. At WOT, back the screws off until they are not contacting the rack bar. turn the fuel screw in until it bare contacts the bar and lock it down. Turn the torque screw in until it barely contacts the bar and then go another 1/4 turn and lock it down. That greatly improved the truck, however I have since then turned them BOTH in round and half (TOO MUCH FUEL). It runs great but the EGT's will climb a little more than I like on a load. I had an old timer turn the timing up a little prior to the fuel adjustment. I think the timing needs to be revisited to help lower the EGT's.....Opinions?
 

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Junior Member
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168 Posts
Need to get rid of the stock turbo and replace it with a wastegated 177148 borgwarner 550 C15. Turbo or even a OR-6051 cat turbo. But yes too much timing or not enough is bad. Should have it meter timed to 20-21°@ 1000rpm and it should be 30-32°@ 1900rpms.
 

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Senior Member
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2,555 Posts
If you turned the screws clockwise (IN) that is less rack travel, thus less fuel, maybe enough less to not spin the antiquated turbo up to make enough air flow to keep things cool, and the scroll action adds a tiny bit of timing too. the more efficient turbo form the 550 should improve things, exhaust temp wise. and DON'T let some "expert" tell you to block the waste gate on the newer turbo.

there is a thread by oldnotslow about the turbo swap, oil line mods and his experience with the 177148.
 
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