new headers, lost power
Thread Starter
|
New User
Joined: Apr 2002
Posts: 5
Likes: 0
new headers, lost power
hello all,
I double posted this in "exhaust forum", too as my bumper is up against the wall,
and I need any advice I can get.
Just insalled Hedman headers and dual Flowmaster 40's on a 85 bronco with a 351-4bbl.
Sounds great at idle and low rpm run, but lost tremendous power at upper range and
pops bad out the tail pipes. I checked to make sure all vac lines are either attached
or plugged. system has no cats ( been gone for a year now), and was running real good before
header install. Havent welded in a crossover yet. Also no O2 sensor in pipe. Wasnt there when I
bought truck. Timing,plug gap, nut behind the wheel is loose???Any input you can give will be greatly a appreciated.
Barry
I double posted this in "exhaust forum", too as my bumper is up against the wall,
and I need any advice I can get.
Just insalled Hedman headers and dual Flowmaster 40's on a 85 bronco with a 351-4bbl.
Sounds great at idle and low rpm run, but lost tremendous power at upper range and
pops bad out the tail pipes. I checked to make sure all vac lines are either attached
or plugged. system has no cats ( been gone for a year now), and was running real good before
header install. Havent welded in a crossover yet. Also no O2 sensor in pipe. Wasnt there when I
bought truck. Timing,plug gap, nut behind the wheel is loose???Any input you can give will be greatly a appreciated.
Barry
Post Fiend
Joined: Feb 2001
Posts: 6,624
Likes: 8
From: Missouri
new headers, lost power
Not a big small block guru but make sure that your gaskets match up to the header exactly the same as they do to the head. You could have a mismatch which would make it idle good but loose top end power.
Posting Guru
Joined: Jun 1999
Posts: 1,100
Likes: 0
From: Durham
new headers, lost power
Sounds like you need just a little more restriction. How big is your exhaust pipe? Another area I would look at is the timing. What is your base timing? What is your total timing? At what rpm does your total timing come in? Last thing I can think of is the possibility of the valves floating. What is the range of rpms that you are losing power? Are your rpms actually higher with the headers and then you lose power?
Thread Starter
|
New User
Joined: Apr 2002
Posts: 5
Likes: 0
new headers, lost power
I fixed the problem. I am the greatest mechanic ever. The problem was multi faceted. I found a bad cxo bypass valve and a stuck inter-electronic shunt positioning relay module socket adapter casing. I bore tested the phrasmatic extractor to make sure it was outletting .008965 ohms and realigned the vacuum controlled compression diaphram inlet exhaust occilator to EXACTLY .0045913770831279 of an inch. That's all. Done. Finished. Runs like a champ. Uhhh....actually I wish I were that good. In reality I crossed # 2 and 3 spark plug wires. STUPID mistake...duhhhh. Sorry I called an air strike for something so blatent. I will however begin saving up $70,000 to buy you ALL a cup of coffee. Thanks again. bsmosk.
