OK here is a question for you experts. I would like more that one expert opinnion. I am going to be running 100 shot of NOS on my car. I am getting high flow Metal substrate cats. I will dial the car in on the dyno for the correct A/F ratio and timming both with and with out NOS.

Questions ?

1. The cats are going to be in the stock position. Should I run 2 1/2 inch cats or 3 or 3inch ?

2. From in back of the cats should I go 2 1/2 to end mufflers for NOS flow ?

3. X pipe ? 2 /12 or larger ?

4. Som one told me the the X pipe works better the closer you put it to the motor. Someone here says further ????

PS I am havung a exhaust shop make changes, so enlarging and downsize fitting is no problem

 

This thread has been official hijacked...

Brent

 

Give me a break ! There been much discussion about Exhaust here and I did'nt have anything to do with it ! JBrady said numorous times to run 2 1/4 exhaust. I was asking because of a different mod with headers was what I was working on.

I will respectfully withdraw if it seems like I am hijacking that was not my intent sorry. But.................... I wonder if you read the previous 2 pages. If not, please do.

 

There are my opinions;

1. No just run 1 race cat. in the middle before the cat back. I would use 3" pipe and cat in the center of the Y section pesonally.

2. I would go 2.5 with jbrady's headers. But on stock headers I would do 2.25.

3. X-pipe is over-rated to me personally. I think H pipe is best.

4. Xpipe is supposed to work better further away from the engine.

 

1. Run dual cats with 2.5" inlet/outlet. This is due to the header outlet being 2.37". Extra flanges should be available for those wishing to custom build downpipes.

2. 2.5" will reduce your power in the driving RPM range. It may help SLIGHTLY under NOS but I would suggest your configuration and muffler choice is much more important here. Personally, I would go 2.25". A single 2.25" will support 300hp... dual 2.25s would support 600hp.

3. Run the same size X or Y pipe as the dual pipe size. EXECUTION is everything. A proper (like Burns) X or Y pipe will increase performance in the low and mid range without restricting top end power. There are multiple styles and theories. I prefer the Burns style to the Hedman or Dr.Gas style but either are good choices. Whatever you do make certain the flow path is smooth, unrestricted and the merge angle tight.

4. I am unaware of a better location that the stock location.

 

nice Pic Hollywood!

Ok, seriously though, doesn't anyone else find the drawing misleading besides me??
H-pipes are soo 1980. X-pipes are just an evolution of the old H-pipe.
The H-pipe when first used was shown to cause a decrease in backpressure. Fairly straight-forward. The X-pipe does the same thing, but is able to continue doing it efficiently through a higher RPM range.

But, back to the drawing. I think it mis-represents the exhaust gas PULSES as "crashing" into each other. It's not really like that. Each pulse is separated from each other due to the crank rotation and firing order.
The pulses do not arrive at the cross-over of an X-pipe at the exact same time.



- this has been brought to you by the voices in my head. -

 

They do 110%.

If you guys want to dispute all this H, Y, X pipe crap just say fork it and go full dual exhuast and be the hero and laugh at everyone else.

With these crap stock exhaust manifolds, non of the **** even matters.

 

Actually there is a difference in function between an H-pipe, a "window" X-pipe and a Merge X-pipe and a Y pipe. The H pipe and Window X work very similarly. The idea is NOT to split the flow but instead create a plenum effect, ie, have an area where the pressure AND sound waves expand into. This deadens and reduces the available pressure to travel back up the pipe. In a Merge X pipe and a Y pipe both flow paths are joined to create a common flow. This works in the same way that joining primary pipes in a header improve flow. The total flow is less resistant to reversion and creates a one way flow path. Once the two sides are joined you can split them off again and retain the effect. All of these devices change the tone of the exhaust. Final tone is determined by total volume and resonance of the components.

 

Since you quoted me, feel free to elaborate in detail then, instead of just saying "they do 110%"

.

 

Do you honestly think at WOT they do not collide??? Please do not make me explain it. Im going to bed.

 

Guys,

This thread is about headers, not the advantages over different pipes. If you have something to say concerning the headers then say it in this post, if not start a new thread or bring it to PM.

Like most people on this thread, we are interested in the headers. That is why we subscribed to a thread titled "Headers for V8 cars."

Let's get this back on topic before it is closed by a mod.

Jonny

 

[QUOTE=jbrady]

3. Run the same size X or Y pipe as the dual pipe size. EXECUTION is everything. A proper (like Burns) X or Y pipe will increase performance in the low and mid range without restricting top end power. There are multiple styles and theories. I prefer the Burns style to the Hedman or Dr.Gas style but either are good choices. Whatever you do make certain the flow path is smooth, unrestricted and the merge angle tight.

J,
What do you mean when you say " merge angle tight. " ? Where are you talking about on the system ? And define " tight "'

Thanks

 

[QUOTE=jgscott]I am talking about the Y intersection. The two feed tubes should join at around a 45 degree angle. You want to maintain the enertia which creates scavenging. Another goal is keeping the volume in the merge collector as small as possible. The tighter the merge angle the larger the volume but the worse for flow. Carefull design is required for an optimum part. Review the Burns stainless site for picture examples.

 

Spoke with the manufacturer yesterday. Passenger side header is welded up and the drivers side should be done today. From there the parts go to Jet Hot. Should ship to me around next Wed. Installation and final fitment confirmation is next. If all fits as intended it is TIME TO ORDER!

I just sent an update email to everyone on the list. If you believe you should be on the list and do not receive the email please PM me asap.