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11-25-2006, 04:22 PM | #1 |
Registered User
Join Date: Sep 2006
Location: Bow Island, AB, Canada
Posts: 166
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lotsa backfiring?
you know when you have a standard and you shift down and let the truck slow its self down while you still have some higher rpms it makes that cool sounding crackling sorta backfireing, well my truck does that some times and its an automatic in drive so im just not sure if its mabe timeing or something, also i just noticed it after i got headers on it so is it just nothing or is it not so good or is it very bad?
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11-25-2006, 06:29 PM | #2 |
67-72 Addict!
Join Date: Feb 2002
Location: The TAX State!
Posts: 7,856
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Re: lotsa backfiring?
Check your timing. Check to make sure your plug wires are not laying on the headers.
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Jim 1970 C/10 Fleetside w/Ghost Flames Lowered 4.5" front and 4" rear (Raked) 355/350 Turbo w/shift kit 10" Redneck Performance Verter w/2500 stall Hooker Super Comps part#2808-1 Performer RPM Air-Gap 12 Bolt w/3:73 gears- Eaton Posi Comp Cams XE262 with 1.6 Crane Energizers, Road Demon 625 and Brodix IK 180 heads |
11-25-2006, 08:49 PM | #3 |
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Join Date: Oct 2006
Location: Cheney, KS
Posts: 669
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Re: lotsa backfiring?
What kind of muffler(s) you running?
Might be a backpressure problem, I had that problem with an S-10 I threw a 396 in. It would backfire the second I let off the gas and keep at it till I gat back on the gas. It was custom 2in longtube-ish headers and straight pipes. It stopped back firing a bit after I put some bullet mufflers on it....then I installed an H-pipe and some 18" tips and it never back fired again. |
11-25-2006, 10:10 PM | #4 |
blood type; Retumbo
Join Date: Jan 2004
Location: next to my reloading bench
Posts: 10,269
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Re: lotsa backfiring?
low exhaust back pressure (created by adding headers) can induce a vacuum in the cylinders during certain rpms. having a cam with larger overlap aggrevates this. what is happening is fresh fuel/air mixture is being drawn in through the cylinder and burning when it hits the hot exhaust valves or header tubes. not only does it make noise it also wastes fuel and overheats the valves. circle track guys tend to like this as the engine does not have to wait for a fresh charge when leaving the corners.
try advancing the timing 2* and leaning the idle (if it will accept it without idling problems) a little bit. test drive and repeat if necessary. you could also go up a notch in octane rating. (higher octane = slower burn) |
11-25-2006, 11:23 PM | #5 |
its all about the +6 inches
Join Date: Jan 2001
Location: Hilliard Ohio
Posts: 2,690
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Re: lotsa backfiring?
another common problem with headers, and can cause a bang upon deceleration, is an exhaust leak.
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11-26-2006, 03:43 AM | #6 |
Registered User
Join Date: Sep 2006
Location: Bow Island, AB, Canada
Posts: 166
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Re: lotsa backfiring?
i have some i think they are either bluebottles or cherrybombs not sure they were on the truck wen i bought it all i know is they are illegal here cuz they dont have chambers in them which you must have here in canada so it could be the not enough pressure in the pipes problem?
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11-26-2006, 03:45 AM | #7 |
Registered User
Join Date: Sep 2006
Location: Bow Island, AB, Canada
Posts: 166
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Re: lotsa backfiring?
oh ya and also i have 1 plug that slightly touchs 1 of the pipes on the headers it melted slightly like half a milimeter just enought to be a cosmetic problem (i think) but i cannot push it in on the plug any more
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