'69 chevelle lq9 exhaust Q
01-02-2007, 12:52 PM
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'69 chevelle lq9 exhaust Q ill be swapping in an lq9 into my chevelle soon and was looking for advice on what size exhaust tubing to run... my plans are: stock manifolds, h pipe, dynomax ultra flow mufflers,, but im not sure about diameter tubing to use,, any suggestions? the motor is stock and will probably remain stock for quite some time.
01-02-2007, 12:58 PM
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Originally Posted by C for Chevelle
ill be swapping in an lq9 into my chevelle soon and was looking for advice on what size exhaust tubing to run... my plans are: stock manifolds, h pipe, dynomax ultra flow mufflers,, but im not sure about diameter tubing to use,, any suggestions? the motor is stock and will probably remain stock for quite some time.
Andrew
01-02-2007, 02:58 PM
#3
Factoring in what Exhaust system to use on your swap is no different that any other is car exhaust system.
What helps is taking into account the following.. 1) how much HP you are producting, 2) how loud you want it, 3) how much room you have for the pipes and mufflers, 4) Street or race. After that, you can work with many of the Local Muffler Shops and/or Manufactors (Flowmater, Borla, etc.) of Kit Systems to suggest what size and system to use.
If you using a stock to a few mod of any LSx engine.... 2 1/2 should be find and a good starting point. Since you don't have to use a Cat.. that will do two things.. a) increase flow and b) make a bit little noise (not much, but some) when you step on the loud pedal..
I am using 2 1/2" on my LS1 Chevelle.. Flowmaster American Thunder Kit.
Hope that helps... Got any pic's of the project yet ?
What helps is taking into account the following.. 1) how much HP you are producting, 2) how loud you want it, 3) how much room you have for the pipes and mufflers, 4) Street or race. After that, you can work with many of the Local Muffler Shops and/or Manufactors (Flowmater, Borla, etc.) of Kit Systems to suggest what size and system to use.
If you using a stock to a few mod of any LSx engine.... 2 1/2 should be find and a good starting point. Since you don't have to use a Cat.. that will do two things.. a) increase flow and b) make a bit little noise (not much, but some) when you step on the loud pedal..
I am using 2 1/2" on my LS1 Chevelle.. Flowmaster American Thunder Kit.
Hope that helps... Got any pic's of the project yet ?
01-02-2007, 03:31 PM
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i was leaning towards 2.5", thanks guys... i have some pics of when i got the car and gutted it, but need to resize them,, i'll take some pics when i get it back from paint and start the swap
bczee, i think i have your swap saved in my bookmarks for reference
bczee, i think i have your swap saved in my bookmarks for reference
01-02-2007, 09:19 PM
#5
I would say 2.5 duals would be enough. I am running 2.25 duals with an x pipe and 40 series flowmasters on my 5.3L with stock camaro manifolds and cats, and the exhaust outflows the cats. At WOT there is only 2-3psi in the manifolds and 0 psi behind the cats. If I drop the exhaust behind the cats my quarter mile time/MPH stays exactly the same, theres no loss running the 2.25" x pipe and mufflers. Its a little loud for my taste, but its a zero loss system so I can`t give it up. 
