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Unread 07-08-2004, 12:52 AM   #1
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Join Date: Jun 2003
Location: Vacaville Ca.
Posts: 137
2.5l and backpressure

I know you need some backpressure fpr low end and what not, but when is it too much??? when ever I downshift, or I am in between shifting my jeep make a pretty loud blat blat blat noise out of the tailpipe, is this normal, I have a flowmaster 50 series and a high flow cat. But the main question I am asking is it ok to have that much backpressure?



Black 1994 YJ 2.5L
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Unread 07-09-2004, 09:15 AM   #2
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Very good question, mine does it too!
I'll be watching for an answer
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Unread 07-09-2004, 11:02 AM   #3
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Originally Posted by JSLRedYJ
Very good question, mine does it too!
I'll be watching for an answer
Ha, ha, ha! It would seem that ALL of us with Flowmasters and high flow cats have asked ourselves the same question!
This is just a guess, but I think that our Jeeps have always made that noise when letting off of the gas while in gear. IMO The difference being stock cat and muffler were restrictive enough to dampen the noise.
Remember how heavy your stock muffler was compared to the Flowmaster? Alot of engineering time and $$$ goes into designing a quiet muffler that has reasonable flow characteristics.
Red 93 YJ
33" X-Terrains/Super 35 kit/Detroit Locker/4.88 gears
RE 4.5" ED lift/SYE & Tom Woods shaft/Tera 4low
Warn bumpers F & R/Warn gas tank skid
4 point harnesses/Poison Spyder sliders
Warrior Corner Guards/JKS Quick Disco's & telescoping front track bar/M.O.R.E. Rear traction bar/PSC ram steering
Borla header/Turbo City intake/Flowmaster muffler/new cat
all propelled by a [B]MONSTER [/B] 2.5l I4
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