You asked...Dyno #'s with "over-axle" true dual exhaust(NO X-PIPE)
04-07-2006, 11:59 AM
#1
You asked...Dyno #'s with "over-axle" true dual exhaust(NO X-PIPE) I posted pics of my completed exhaust a while back and there was a few questions about how much not having an X-pipe would effect my rwhp. https://ls1tech.com/forums/showthrea...e+dual+exhaust Well, got it dynoed. Here are ALL of my performance mods: SLP CAI, SLP lid, SLP 85mm MAF, SLP bellow, K&N filter, ASP 25% underdrive, Edelbrock Victor Series LT's, High flow cats, Complete custom true duals, Dynomax Bullets, Comp Cam 222/224 .566/.568@112lsa, tuned by R.P.M. My SS is an 02, so it has the LS6 intake. 400.88 rwhp, 387.37 rwtq. 382 rwhp before the tune. There is a pic of the dyno sheet and videos in the car domain link in my sig. So to those who say, "wheres your X-pipe...you need an X-pipe!" I say, "you can keep your f'n X-pipe." 
04-07-2006, 12:46 PM
#3
That's not too bad. I still think you are leaving power on the table though personally. It doesn't look like it would be hard to put an xpipe onto anyways. Just cut out a 12" section of your intermediate pipes and install the X. You know, I know there are a bunch of people here that would probiably agree with me.
You feel up to a friendly wager and a real world test? How about getting an idea from the exhaust shop that did your exhaust how much it would cost to fab up a xpipe section that would have slip fit ends on each end that way you could just cut out the intermediate section and just slide in the Xpipe and also make up pipes to put it back the way it was. Being you have a positive trader rating I would wager you are a man of your word. I'd be willing to put up alittle cash and I'm sure a number of others would as well as long as a few conditions are met. Car must be dynoed in the morning with your setup and later in the same day when the outside conditions are approxiately the same with the xpipe in place. IE 11:00 am dyno and a 4:00 PM dyno. No dyno tricks same dyno same dyno operator same RPM band dynoed in. This is a good platform to test this on being you have an M6 so you won't have an issue with converter flash or anything like that.
If we are correct you repay everybody that put up cash. If you are correct nothing lost on your part obviously. What do you think? Fellow members what do you think?
You feel up to a friendly wager and a real world test? How about getting an idea from the exhaust shop that did your exhaust how much it would cost to fab up a xpipe section that would have slip fit ends on each end that way you could just cut out the intermediate section and just slide in the Xpipe and also make up pipes to put it back the way it was. Being you have a positive trader rating I would wager you are a man of your word. I'd be willing to put up alittle cash and I'm sure a number of others would as well as long as a few conditions are met. Car must be dynoed in the morning with your setup and later in the same day when the outside conditions are approxiately the same with the xpipe in place. IE 11:00 am dyno and a 4:00 PM dyno. No dyno tricks same dyno same dyno operator same RPM band dynoed in. This is a good platform to test this on being you have an M6 so you won't have an issue with converter flash or anything like that.
If we are correct you repay everybody that put up cash. If you are correct nothing lost on your part obviously. What do you think? Fellow members what do you think?
04-07-2006, 12:53 PM
#4
Originally Posted by kossuth
That's not too bad. I still think you are leaving power on the table though personally. It doesn't look like it would be hard to put an xpipe onto anyways. Just cut out a 12" section of your intermediate pipes and install the X. You know, I know there are a bunch of people here that would probiably agree with me.
You feel up to a friendly wager and a real world test? How about getting an idea from the exhaust shop that did your exhaust how much it would cost to fab up a xpipe section that would have slip fit ends on each end that way you could just cut out the intermediate section and just slide in the Xpipe and also make up pipes to put it back the way it was. Being you have a positive trader rating I would wager you are a man of your word. I'd be willing to put up alittle cash and I'm sure a number of others would as well as long as a few conditions are met. Car must be dynoed in the morning with your setup and later in the same day when the outside conditions are approxiately the same with the xpipe in place. IE 11:00 am dyno and a 4:00 PM dyno. No dyno tricks same dyno same dyno operator same RPM band dynoed in. This is a good platform to test this on being you have an M6 so you won't have an issue with converter flash or anything like that.
If we are correct you repay everybody that put up cash. If you are correct nothing lost on your part obviously. What do you think? Fellow members what do you think?
You feel up to a friendly wager and a real world test? How about getting an idea from the exhaust shop that did your exhaust how much it would cost to fab up a xpipe section that would have slip fit ends on each end that way you could just cut out the intermediate section and just slide in the Xpipe and also make up pipes to put it back the way it was. Being you have a positive trader rating I would wager you are a man of your word. I'd be willing to put up alittle cash and I'm sure a number of others would as well as long as a few conditions are met. Car must be dynoed in the morning with your setup and later in the same day when the outside conditions are approxiately the same with the xpipe in place. IE 11:00 am dyno and a 4:00 PM dyno. No dyno tricks same dyno same dyno operator same RPM band dynoed in. This is a good platform to test this on being you have an M6 so you won't have an issue with converter flash or anything like that.
If we are correct you repay everybody that put up cash. If you are correct nothing lost on your part obviously. What do you think? Fellow members what do you think?
04-07-2006, 12:57 PM
#5
Sounds like I get shafted either way. If I win, you pay for the labor and dyno time? So I wouldn't get anything(ie:hp) other than a few new welds on my exhaust. If I lose, then I pay for labr, dyno time, and you guys? Not so much. Besides, the purpose of an X-pipe is to scavenge, right? Why would I need to scavange with 2 2.5" pipes?
04-07-2006, 01:23 PM
#6
Hey that's cool, thought I would throw it out there. You want to scavage with any setup really. Your header collecters are setup to scavage from each tube if properly designed. That's why the tubes are supposed to be oriented in the collectors the way they are.
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04-07-2006, 01:46 PM
#8
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The X pipes are better than straight exhaust pipes, hands down. Now it isn't a whole new world kinda difference, but it is quite a bit better. I think it was Morgan McClure Motorsports that first put an X pipe on a Winston Cup car and took it to Daytona and blew everyone's doors off. They had covers all around the car so noone could look under it and see what they did.
Why do you need scavenging with 2 2.5" pipes. It all has to do with exhaust pulses and you'll have to look it up for a full explanation. But the bottom line is the X pipe, sometimes H pipes are as good or better, will use the exhaust pulses from one bank to pull the exhaust charge from the other bank out of the cylinder and then in turn, that exhaust pulse pulls back on the first bank.
Your car put down strong numbers, but that doesn't really prove anything since you don't have a comparison between the two. I know you seem to think everyone is just hopped up on the X pipe bandwagon, but I used to live in Mooresville, NC and rubbed shoulders with a few engine builders and had this specific conversation with them. The X pipe is the best and second best is an H pipe and then straight pipes. That doesn't mean your straight pipe setup is junk, it is obviously performing well, but it's not the best in comparison, especially as someone else said, in terms of power under the curve.
Why do you need scavenging with 2 2.5" pipes. It all has to do with exhaust pulses and you'll have to look it up for a full explanation. But the bottom line is the X pipe, sometimes H pipes are as good or better, will use the exhaust pulses from one bank to pull the exhaust charge from the other bank out of the cylinder and then in turn, that exhaust pulse pulls back on the first bank.
Your car put down strong numbers, but that doesn't really prove anything since you don't have a comparison between the two. I know you seem to think everyone is just hopped up on the X pipe bandwagon, but I used to live in Mooresville, NC and rubbed shoulders with a few engine builders and had this specific conversation with them. The X pipe is the best and second best is an H pipe and then straight pipes. That doesn't mean your straight pipe setup is junk, it is obviously performing well, but it's not the best in comparison, especially as someone else said, in terms of power under the curve.
04-07-2006, 03:56 PM
#11
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i love the setup and id like to get one made similar just with more quiet mufflers,BUT with that setup why didnt u just have an X put in right where they come close goin over the tunnel brace. just have one welded in itll cost u like $100 bucks probably and why not u can only gain more power.if u had a setup that made it hard id understand but its there u just need those 2 pipes connected now.
04-07-2006, 04:32 PM
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Hey Zeus, nice numbers, and a WICKED sounding car!
That being said, here's the dirt behind an (insert letter of the day here)-pipe. Any American V8 has two points in the firing order where two cylinders on the same bank fire in sequence, one time per bank. That gives the American V8 that mean sound that only a V8 can produce. For example, LT1-back Chevy engines, and all Mopars have the same firing order, 1-8-4-3-6-5-7-2. Broken down into banks 1 and 2, you wind up with 1-2-2-1-2-1-1-2. This makes for two pulses right after each other, then a void that can actually stop exhaust flow momentarily, causing the next exhaust pulse to have to "push" the gases out, costing you power. Reason it doesn't hurt top-end as much is because there's not enough time for the exhaust to slow down.
Now, what an (insert letter of the day here)-pipe does is open up a way for that out-of-sequence pulse to help keep exhaust flowing, and since the two back-to-back pulses occur at a time when there's a void in the opposite bank, that extra pulse keeps the momentum of the other bank from decreasing, keeping exhaust velocity up, and improving exhaust scavenging, thus improving power under the curve.
These guys do have a point. However, with your setup, I believe an H-pipe would be the way to go given how close your pipes run to each other. It shouldn't be that hard or expensive to do, either.
Hey, I tell you what... I have a really short equalizer tube here at the shop that I made for my WS6 before deciding to fab a whole different aminal for an H-pipe. If you want it, I'll give it to you... just cover shipping. It's 2 1/2", so it'll fit right into your getup. Just let me know the distance between your pipes where they first start to run parallel to each other. I'll notch the ends to fit that spec, and whenever you feel like it, you can get it welded in. It won't give you anymore power up top, but the pulse equalization it brings will up your low to midrange grunt. Should also help out with MPG with everyday driving.
That being said, here's the dirt behind an (insert letter of the day here)-pipe. Any American V8 has two points in the firing order where two cylinders on the same bank fire in sequence, one time per bank. That gives the American V8 that mean sound that only a V8 can produce. For example, LT1-back Chevy engines, and all Mopars have the same firing order, 1-8-4-3-6-5-7-2. Broken down into banks 1 and 2, you wind up with 1-2-2-1-2-1-1-2. This makes for two pulses right after each other, then a void that can actually stop exhaust flow momentarily, causing the next exhaust pulse to have to "push" the gases out, costing you power. Reason it doesn't hurt top-end as much is because there's not enough time for the exhaust to slow down.
Now, what an (insert letter of the day here)-pipe does is open up a way for that out-of-sequence pulse to help keep exhaust flowing, and since the two back-to-back pulses occur at a time when there's a void in the opposite bank, that extra pulse keeps the momentum of the other bank from decreasing, keeping exhaust velocity up, and improving exhaust scavenging, thus improving power under the curve.
These guys do have a point. However, with your setup, I believe an H-pipe would be the way to go given how close your pipes run to each other. It shouldn't be that hard or expensive to do, either.
Hey, I tell you what... I have a really short equalizer tube here at the shop that I made for my WS6 before deciding to fab a whole different aminal for an H-pipe. If you want it, I'll give it to you... just cover shipping. It's 2 1/2", so it'll fit right into your getup. Just let me know the distance between your pipes where they first start to run parallel to each other. I'll notch the ends to fit that spec, and whenever you feel like it, you can get it welded in. It won't give you anymore power up top, but the pulse equalization it brings will up your low to midrange grunt. Should also help out with MPG with everyday driving.
