[V8] header wrap question

[qshipq at aol.com]

 I personally don't buy any performance gains with this mod on a v8.? With it's double walled 'true' headers you already have good heat retention and velocity, then vs the 3.6 the 4.2 exhaust has the xflow? before the cats, you have faster lightup time, and the exhaust is already larger and mandrel bent for good flow.? Any (nominal) gains will come post cat, especially mid muffler where mid range torque can be picked up using a higher flow resonator.? Given doing something, coating is a better choice, but I only use it to move heat from the engine bay.? I have seen no dyno number (even on a turbo I5) where wrap showed any improvement in engine performance.

IIRC, you can get a Borla 2x2.5 dual in dual out muffler that just fits the chassis (BTDT on a type 44 turbo car) and I tend to prefer their low profile xr1 series race mufflers as mid mufflers to take out the highway drone.? They are low profile too, which is necessary to not make the mid muffler the lowest part of the exhaust.? Magnaflow also makes some 4in round resonators good for mid muffler replacement.

All that said, I'd really like to see dyno numbers where any $/HP benefit would come on 'improving' that 4.2 exhaust.? Stock, it's mandrel bent, it's larger than the 3.6 exhaust, and it flows well to redline.? I don't think you can improve the airflow enough on a non force-inducted 4.2 to see gains in exhaust work.? Header wrap is racing exhaust work, money is better spent elsewhere first.? 

IMO

Scott J
92 v8 - chipped
ex2ex
91 v8 - no longer chipped - chipped ecu for sale




 


 

-----Original Message-----
From: Ron Wainwright <ron_01056 at yahoo.com>
To: Tony and Lillie <tonyandlillie1 at earthlink.net>
Cc: v8 at audifans.com
Sent: Sun, 22 Jun 2008 9:06 am
Subject: Re: [V8] header wrap question










Yeah, thats what I was told. The wrap will hold
moisture.
 What about somekinda coating. Such as Jethot, swain,
or ceramic?

 But who knows.....I'm not quiet sure this exhaust
will stay on the car for long. What I really want's
the exhaust ends to exit before each tire in the rear.
But @ the same time I'd really all so like to exit a
system the way it's supposed to be with DTM tips.

 But I all so just wanna get this car rolling again.
It's been sitting since last Dec & I'm itching to put
some WRX in my rear view mirror!

 Ron

--- Tony and Lillie <tonyandlillie1 at earthlink.net>
wrote:

> The only downside is most of the header wrap
> products hold water till warmed 
> up, which will rust the system a bit faster.
> 
> But, if performance is what you are after, yes, wrap
> them. Two reasons. 
> First of all, you want the exhaust system hot for
> max performance. 
> Otherwise, you are fighting pulses back into the
> exhaust system that create 
> backpressure. Second, it will also cause the cats to
> light off faster, which 
> helps with emissions, and more importantly, their
> longevity.
> 
> Tony
> 
> ----- Original Message ----- 
> From: "Ron Wainwright" <ron_01056 at yahoo.com>
> To: <v8 at audifans.com>
> Sent: Saturday, June 21, 2008 12:34 PM
> Subject: [V8] header wrap question
> 
> 
> > OK, so the only thing I'm waiting on are some
> motor
> > pieces to get back to me from powder coating, then
> I
> > get to stuff this beast in my 5sp.
> > But I had a question.......I wrapped my headers in
> > Black header wrap & have enough leftover to wrap
> my
> > entire exhaust if I wanted.
> > The exhaust still consists of the OE cats, into a
> two
> > into one 3" flowmaster pipe to 3" all the way back
> to
> > the rear SS muffler. Is it a worthwhile/good idea
> to
> > wrap the end of the cat pipes & the 3" pipe back
> to
> > the rear?
> >
> > Thanx
> > Ron
> >
> >
> >
> >
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> 



      
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