DonaldK

"Helped" build my '06 Friday (23rd). At one point, I stood under the car holding the factory "X-pipe" and asked if all of them have the connecting cross-over (4" or so) exhaust piece as mine did. Answer: yes!

What is the difference between aftermarket and the factory X-pipe? Both have a cross-over connector.

BTW - WHAT AN EXPERIENCE! I'll share shen I figure how to post pics.

Tying to get ready for delivery in 10-12 days!! Z-51/6spd/VR/BLK/BLK vert.

Thanks for explaining this to me.

Don K

MitchAlsup

Both the H-pipe and the X-pipe allow both sides of the exhaust piping to be used to move exhaust gasses out of the way of the next set of exhaust gasses.

The American V8s all have 90 degree crankshafts (also known as 360 degree CS). This gives rise to the burble of the american v8s. This crankshaft arrangement gives better secondary balance in the engine and leads to smoothness; but results in an uneven firing order and exhaust order LRLLRLRR.

THe H-pipe and the X-pipe allow the doubled up pulses to utilize the 'other' pipe for smooth exhaust performance and lower back pressure. The H-pipe only works in the lower RPM range and effectively turns off when the RPMs get above a certain point. The X-pipe does not have a high RPM cutoff point and works across the whole RPM band.

robvuk

My question is: Is there a reason the firing order can't be LRLRLRLR?

andreas g.

H-Pipes are cheaper to make so factories make the cheapest possible. Since exhaust gages don't really like to make Right and Left turns, H pipes don't work as well as x-pipes. When exhaust gases pass over the x-pipe the crossing over effect aids in scavenging the combustion chambers of exhaust gases. Which aids in the filling velocieties of the incomming charge, ie better performance. It's nothing great ,but it does increase torque, and HP.

Buddy A

Sorry for the newbie question. Does the Vette have a factory H-pipe? And so an X-pipe would aloww better exhaust flow?

Guppies

Correct on the factory H-Pipe - also, the backfiring while decelerating with an H-Pipe connected to anafter market exhaust is an invitation to be pulled over in some areas. The X-pipe greatly reduces (if not eliminate entirely) the backfiring.

ein Tier

So what exactly causes the poping and crackling when you do an abrupt lift-off of throttle or use engine braking?

'Cause I really, really like it.

DonaldK

Thanks for the answer to my original question. I guess I understood the reason for connecting the two exhaust pipes - I just did not realize that the flow through/across the connector would be that much better with an "X" configuration that across the factory "H" configuration. The post that explained 90 degree vs. 45 degree turns makes some sense to me. Does anyone have dyno numbers on the difference???

Again thanks to all the Vette nuts on this forum!!

MitchAlsup

The 90 degree crankshaft has 'better' balance because (in laymans terms) each bank always has one cylinder {ac,de}celerating near TDC, one {ac,de}celerating near BDC, one traveling downward and one traveling upwards. The cost is rotational weight (crankshaft balancing weights) and a lack of equally spaced firing/breathing order.

The 180 degree crankshaft has two cylinders {ac,de}celerating at TDC/BDC and two cyclinders {ac,de}celerating at TDC. It is bascially 2 4 cyolinder inline engines on a common crankshaft. The 'flat plane' architecture uses the other bank to provide secondary balance to the engine whereas the american V8 uses cylinders within each banck for secondary and tertiary balance.

The 'flat plane' which does have LRLRLRLR firing order has the advantage of equally spaced exhaust and intake periods, but has about 4 times as much vibrational energy then the 90 degree crankshafts. Racing engines (e.g. not NASCAR) use 180 degree cranks because they are stronger and lighter and the don't really care if the drivers feel all vibrated up at the end of a stint. So does Ferrari and did Lotus when they had a V8.

jrjen2

It is good to finally read a post where everyone answering the question doesn't just beat the guy up for asking. I learned something new today about X-pipes.

wlee013

Thanks for layman explanation. I understand the reason for X-pipe now.

robvuk

Thanks Mitch

I knew about the Xpipe and firing order but just never gave it enough thought as to why.

C6FirstVette

I like visuals...these pics show how gases will flow much more efficiently for the X pipe over the H pipe>>>




Michael

Zig

yes.. no... well actually......

I believe you would need a different crank, and new programming, etc. etc. etc.

I've also wondered what it would be like if both of the cylinders that are at/near tdc fired. maybe i'm wrong but last time i heard you will have two pistons in firing position during a cycle but only one of them fires. yes, it would take a custom cam, since you would need to open open more than one set of valves, etc. etc. etc. but just wondering what it would do for power output. would it in essence double the output ??

SteveL2

Great answers by those who responded in this thread.

rmitchell242

maybe you would have more like a big cubic inch 4 cylinder

dshaner1

Thanks everyone who's posted....I have learned a lot. It has been explained that the X pipe will add power and torque in the upper RPM's over an H pipe...any idea how much? I am considering buying the B&B headers to go with my factory exhaust with Magnaflow cans, and perhaps I should invest in the B&B X pipe as well?!?!?!

I am thinking it would add 2-5 RWHP over stock, am I close

Also, Is the factory H pipe 2.5" in diameter? How about buying one of the Magnaflow prefabricated universal X pipe sections (they are only about 12" long) and welding that in place of the factory H-pipe. This seems like a cost effective way of upgrading to an X pipe...thoughts

dshaner1

What are your thoughts on something like this?

http://cgi.ebay.com/ebaymotors/X-PIP...QQcmdZViewItem

jimman

There was a dyno day at a major Exhaust Manufacturer in Orange county CA a couple of years ago. The end of the day was the before and after with one their systems. I remember them having a tech review with a cutaway system explaining the X pipe in their system and how it works. Well when they did the before and after with relearn they lost 8 rwhp, got to love it. Of course that was with a C5 and the C5 didn't seem that responsive to Exhaust schemes.

jschindler

While there is some interesting information in this post, I think there is also some information left out.

Does anyone really believe that with todays computer controlled manufacturing process, that there is any differnce in manufacturing cost? I seriously doubt it.

I can address why it is an "H" pipe from the factory. If you go back about four years ago in the C5 section of the forum, there were a great many posts about this. It was pretty well documented that the "H" was to eliminate what I will call a sound issue in the exhaust. It's been a while, so I don't remember all the specifics, but I'm pretty sure that it was sound related - not performance or cost.

There have been many posts, but very little concrete infomation on actual performance differences. In fact, like Jimman said, it's seems like there were actually some posts indicating performance losses. In fact, at one time, B&B told me they would not make one (for the C5) because they never found a gain. I know they make one for the C6 - I don't know if they found a gain, or just decided that if people were going to buy them, they might as well jump on the band wagon.

I have never tried one, so please understand that this is all just my memory of the experiences on C5's.