Cross over pipe worth it?

[gbskunk2006]

I have a 2 1/2 inch dual exhaust setup on my 86 GMC C15 with a 4.3 Liter V6.  Will adding a cross over (i.e. H-Pipe or X-Pipe) really make a big difference in;

1) Horse Power?

2) Torque?

3) Sound?

Thx in advance?

[choptop]

T answer 1 and 2, I don't think it will make any difference. You already have an overkill exhaust as is, maybe too much. As for the sound, the x pipe tones the exhaust down, and gives it a more balanced sound. Don't know about the sound on the six with an x pipe, but I DON'T like them with straights, so it may make it sound better, but performance wise, it won't make enough difference to justify the cost. But, just think, when you swap in that hi-po smallblock, the exhaust will already be done.

[Blue 82]

I put an "H" pipe on my 350 truck and noticed a slight increase in low/mid torque judging from the SOTP meter

I don't have any before/after timeslips to verify a gain/loss in HP though.

I did experiance a nice reduction in noise

Here's some cool X pipes from Burns Stainless

[VileZambonie]

You don't have a 4.6L If it's a v6 it's a 4.3L

[eventhorizon66]

I experienced a noticeable increase in low end torque and a decrease interior resonance when I added an h-pipe to the custom straight dual exhaust on my old '99 Suburban.  Well designed x-pipes are supposed to be beneficial at all rpms/loads, but are more expensive and likely not a significant improvement over an h-pipe on a 4.3L.

[Dragon]

As Chop pointed out, your 2.5 System is overkill for a Six Shooter no matter how you cut it....   Adding a Cross-Over H-pipe should give you some of the power back, but the Sixer is having trouble Huffing through such big lungs...   Generally a 2" would be prefered, but a 2.25" would be slightly pushing it....   Now if you had a single outlet exhaust system, 2.25 to 2.5" would allow that six to breath like it had a 2"-2.25" dual system....

The Best actual Cross Over design, is a True X- Pipe(Such as what Blue has suggested)...  Old School H-Pipe cross overs won't be as beneficial as an X, as they create more of a Pressure Bumper between the two sides....   Ofcourse H-pipes are Generally prefered to not having a Cross Over Pipe at all, when it comes to applications that lack the ability/room to run a True X-pipe...

[VileZambonie]

http://store.73-87chevytrucks.com/merchant2/merchant.mvc?Screen=PROD&Store_Code=7&Product_Code=SGT80&Category_Code=73-87UHood

[gbskunk2006]

Well, I decided to go for it.  IMO it's improved the low end torque and the sound is a little deeper, but actually quieter inside the cab.

This is my SOTP meter test:)

Improved low end torque;
-from idle (without giving extra gas) it will slowly "crawl" up a hill with about 6-8 degree incline.
-seems to maintain it's cruising speed longer once I take my foot off the pedal.

Deeper Sound;
-just stood outside the cab when idling.  Now let's see if the neighbors notice when I leave for work a 5AM

Sorry, no dyno test in-store for this six shooter

[eventhorizon66]

Was it an H-pipe you ended up adding to your current system?

[comp]

got any pics of your system ??

[gbskunk2006]

It was the H-pipe.

Sorry, I should have taken some photos while she was up on the hoist.  The guys that did the work do a lot of custom exhausts so all I can say is that they did a real clean job!

http://forum.73-87chevytrucks.com/smforum/index.php?topic=8625.0

[comp]

 you can add them later 

[SUX2BU99]

Who did the work?

[gbskunk2006]

These guys originally installed my duals so I went back to them for the cross over pipe.  Only charged me $80.

http://www.quietmufflerandbrake.ca/

Cheers