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Question for tuners: what part of the exhaust is the most restrictive?

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Hello guys - As the title says, I am curious about which part of the exhaust is causing the most restriction.

I have read several threads about putting headers on, OR X-pipes, over-axles, etc and I have ruled out doing the headers because a) too much expense and b) too much of a pain to install. I would consider anything aft of the headers, though, and just wanted to see if any of the tuners/experts could tell me what they would change out. I currently have GT500 mufflers on it and I know that the axlebacks aren't where any real gains can be had. Oh, I don't mind some extra noise although I don't want it to sound like a straight-piped methanol-fueled drag car either!

If this is a stupid question, please point me in the direction of a thread that might answer my question. Thank you in advance!

John
 
I've been told removing the cats is good for almost 20 HP so and off-road X pipe would be where I'd start. Give Shaun at AED a call and he can talk you through all of this.
 
konablueeboss302 said:
If this is a stupid question, please point me in the direction of a thread that might answer my question. Thank you in advance!

John

No question is a stupid question, if you don't know the answer. This is the palce to ask, these guys know a lot about what works and what doesn't.
 
Along these same lines I just got my SCT SF3 from the tuner but am waiting for him to email the tune. I was reading through the standard options and you can now switch off the rear O2s yourself when loading a tune. I couldn't do that on my older X3, it had to be done by the tuner. Would you be able to load a standard SCT tune and just select the option to turn off rear O2s without getting a custom tune or is it not compatible with the Boss? You can also change the rev limiter and raise or remove the speed limiter. In addition you can still change fan settings, rear gears, tire size and spark advance like they had available before.
 
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Thank you for all of the replies everyone! Here's an article I ran across from another forum with dyno tests of catless X and H pipes.

http://www.svtperformance.com/forums/front-page-news-143/801975-svtperformance-plumbing-101-lethal-performance-offroad-h-x-pipe-test.html

Seems like yanking the cats may be my next step. Or maybe a aluminum driveshaft. Or maybe an open intake. Or or or!

As for Shaun, yes, he is amazing. He tuned a car that I 'know' very well (cough cough not mine if you are connected to Ford and reading this cough cough). The engine feels a lot snappier and sounds even better/deeper in the way that properly stoich engines always do. Oh, and the overrun crackle is just icing on the cake.
 
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The resonators have a two inch core which would seem to present a restriction. I haven't seen any back to back dyno runs after removing them.
 
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After doing some research and talking to some people in the know (including [email protected]), it seems like I'm headed towards putting an H-pipe on it. There aren't a whole lot of options since I insist on keeping my side pipes and I also understand that X-pipes are good for a few extra hp over an H but I prefer the deep sound of the H.

I would be interested to hear if anyone has any experience with H-pipes on the current Roadrunners/Coyotes?

John
 
konablueeboss302 said:
After doing some research and talking to some people in the know (including [email protected]), it seems like I'm headed towards putting an H-pipe on it. There aren't a whole lot of options since I insist on keeping my side pipes and I also understand that X-pipes are good for a few extra hp over an H but I prefer the deep sound of the H.

I would be interested to hear if anyone has any experience with H-pipes on the current Roadrunners/Coyotes?

John
Mine's going on this week. I'll let you know.
 
konablueeboss302 said:
I look forward to hearing your thoughts about it, Gary.

Which H pipe did you go with?

John
Kooks without side pipes. You can get it with or without but I opted to save the weight and my ears. It's going to be pretty loud and having that come out right next to the windows might be a little much, especially during extended track sessions.
 
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The de-catted Kooks H was what I was looking at, too. I understand what you are saying about the weight and noise but at least as far as the noise goes, I figure that I can always use some exhaust discs to tone it down if I find it too loud.

The other ones that I am looking at are the MRT catted ones.
 
Installing Dynomax Ultra Flo axle backs and want to retain "resonator" mufflers to kill exhaust drone, but want to address the restriction of the OEM resonators. Thinking about replacing them with 3" Dynomax Race Bullets (or similar bullet-style mufflers). Has anybody done anything like this?
 

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