Custom Tune Clarification

[bubbatrucklover]

I know that Jarrod and Dan are both running long tube headers and they both have 4wd trucks.

I'm just wondering if for some reason it doesn't show "factory fit" for 4X4's as a disclaimer of sorts because it would move the position of the cats back.where as for 2wds it wouldn't. I didn't want to order them at $500(ish) and find out there was a routing issue.

Ok... Think about it this way.. You have two rivers flowing and you confine them down to one.. and then split it back to two (if you do a Y and then another Y.. ) You'll have a bottle-neck of flow where you confine it down to one and then split it back out. I wouldn't do that...

If you're going to do duals, do true duals.. all the way back.. Yeah, a cross-over pipe will help balance pressures. So, you'll want that.

But a Y and then another Y..... No, I wouldn't do that..

Didn't make sense to me either I was just looking at the crossover pipe and trying to figure out it's application.

I might not be the BIGGEST idiot at times,but I can be an idiot.

 

[Texas Jim]

Bubba... You need to go talk to a couple...or more... "GOOD" exhaust shops...
People all over the country are running long tubes, TRUE DUALS and 4WD.

Seriously... if I wasn't going long tubes... I would just maybe put a different muffler on it, and save the money I would have wasted on shorties...
Unless I just wanted them for the looks...
Just about everything I have ever read about Shorties say that there is VERY LITTLE performance increase over the stock manifolds.

Unless you just want the "LOOK" of headers.... you need to seriously look at long tubes and a "GOOD" muffler shop to install an "X" pipe and true duals to get the most benefit out of them.

With Shorties... it is mostly "ALL SHOW" and "NO GO"...

 

[CJ Hungus]

Lt's to True Duals with an X pipe.

 

[Darkanion]

Didn't make sense to me either I was just looking at the crossover pipe and trying to figure out it's application.

I might not be the BIGGEST idiot at times,but I can be an idiot.

Crossover pipe for true duals? Equalize pressure between the two pipes and help things flow more efficiently.

Two pipes to a Y and then another Y to two pipes? ClusterfWONk...

 

[Texas Jim]

Didn't make sense to me either I was just looking at the crossover pipe and trying to figure out it's application.
I might not be the BIGGEST idiot at times,but I can be an idiot.

Crossover pipe for true duals?
Equalize pressure between the two pipes and help things flow more efficiently.

Two pipes to a Y and then another Y to two pipes? ClusterfWONk...

Yeah... what Michael said...

The reason a crossover or "X" pipe is needed is...the firing order is not equal between the two banks of cylinders...and uneven exhaust pressure pulses are traveling down the pipes...
They used to call "X" pipes "BALANCE" pipes because they help balance the exhaust pressure in the pipes.

The firing order on the GM V8 is...1-8-7-2-6-5-4-3

Notice that early in the firing order...2 and 6 (BOTH ON THE SAME BANK)..fire one right after the other... and late in the firing order..5, and 3... (ALL ON THE SAME BANK).. fire one after the other...
This creates a high pressure exhaust pulse that is traveling down the pipe, while the other pipe is at a much lower pressure.
When the exhaust pulses reach the "X" pipe... some of the pressure will naturally go to the pipe with LOWER pressure.. thus smoothing out the exhaust flow thru the pipes.

If the firing order was 1,2,3,4,5,6,7,8....it wouldn't be needed...but since it is NOT that way... it is pretty essential..

Chrysler corp started putting on at the factory in the 1960's on the Chrysler 300 to get a little more FREE HP...

 

[CJ Hungus]

FYI, the firing order for the LS engines are 1-8-7-2-6-5-4-3

 

[Texas Jim]

FYI, the firing order for the LS engines are 1-8-7-2-6-5-4-3

I knew that... don't know why I wrote it that way... I will blame it on not enough coffee yet...

The older V8's were 1,8,4,3,6,5,7,2

 

[Hotty Toddy]

Originally Posted by ScottyBoy
I know that Jarrod and Dan are both running long tube headers and they both have 4wd trucks.

Think they could comment on their setups? I'd be very interested.......

 

[NMRam]

Here is Jarrod's LT install thread.

http://www.truckmodcentral.com/forums/showthread.php?t=6038

 

[svensk]

Good header companies make matching off-road y-pipes that bolt right up. That's if you don't want to run duals all the way back.