stainless header for gs

[drhach]

Sorry this is so long.

It has been said here that there isn't much to this. That statement is the kind of statement someone would make who has been looking at pictures of header fabrication. If you have ever done it, and I mean done it to the level where the end product is a functional piece of art; then you know the difficulties.

I have to respectfully disagree. I assume that you are referring to me, maybe you aren't. By saying what I said, I was not trivializing the process. In the end though, I have put a lot of time in to making a set of headers, including modeling a complete engine in Ricardo and designing the header with a 3d Modeling program (Pro/E). I spec'd the design, I cut the tubes, I welded them, I ground the welds, I polished the header, I sourced the coating specialist, I installed them and they worked damn good both on the dyno and in the real world. In hindsight, it wasn't that big of a deal. Most of what I've done wasn't necessary for the kinds of applications that these bikes will see. A person with access to a good MIG/TIG welder a bandsaw and a measuring tape could do it. You don't need an engineering degree. Hell, tack weld the parts and take them to someone else to finish them. A good weld is strong and wont compromise the part in any way no matter how many sections you make it out of. Its a very realistic thing to do for any metal fabricator. Sorry to ruffle your feathers. What I said is based on my experience of actually doing it, not reading about it or hearing about it being done.

[posplayr]

Sorry this is so long.

It has been said here that there isn't much to this. That statement is the kind of statement someone would make who has been looking at pictures of header fabrication. If you have ever done it, and I mean done it to the level where the end product is a functional piece of art; then you know the difficulties. For a small quality production run jigs would have to be built.

The small pieces of tubing cut into various sections, create lots of negative issues. It is weaker, it looks bad, it creates additional internal drag, which lowers power. The sectioned headers are easier to make without bending equipment. They do require lots of extra welding, which can add to the costs. All those seams have lots of stress built up from the expansion and contraction of the welding process. Certain areas of headers on some engines will stress relieve themselves from the heat of the exhaust system. The areas that are not stress relieved are the areas that have the likely potential to develop cracks. There is a lot to making a functional header that makes power, that is also one you would be proud to put on your bike. I hate seams on a bike header, but on some designs you need them

I would be open to making stainless or Titanium, both are a pain to work with, with the TI being the most difficult. The 6AL4V Titanium is as strong, or stronger than 4130 chrom moly steel, and about half the weight. The Titanium is expensive, and I would most likely have to import it. I have a complete private machine and welding shop. Because I work with some classified projects, I am not open to the public. I am always looking for interesting items to fabricate. I have been looking into building some Titanium swing arms for a Hyabusa, and I still have room for one more project this quarter.


In order to talk about a price, the design parameters would have to be set. A drawing with details would have to be developed. Certain designs are costly to fabricate. The design parameters can triple the production cost. Ball park figures are tough. I will take a whack at them. What I would suggest is a design that uses a modern slip on silencer for a particular popular production bike to save cost. Then design a header and silencer mounts for the GS. I have great sources for the raw material. If I have to go outside these channels for material that is unavailable, the price would go up

In a qty of 16

Stainless header to take a modern slip on silencer $500 to $850
Stainless header somewhat like the old original Vance & Hines design, but not direct copies $650 to $1050

Titanium considerations. Most people hear the word titanium and go bonkers. Pure titanium is about 1/3 the strength of 4130 chrom moly. Lots of the titanium bike parts are made out of pure titanium. 6AL4V aerospace grade Titanium is 3 times stronger than pure titanium, and can exceed the strength of 4130 chrom moly steel. This is SR71 Black Bird stuff

6AL4V Titanium header to take a modern slip on silencer $900 to $1400
6AL4V Titanium header somewhat like the old original Vance & Hines design, but not direct copies $1200 to $1600.

Remember these are just rough estimates.

Texasgs,
I really appreciate your considered response to this thread. I'm no GS expert but have been searching for GS1100E exhausts for sometime (2 years) on ebay. While some might argue, I think there might be an opportunity with 80-86 GS750(pre-83 only)/1000/1100/1150 exhausts. All of these bikes use nearly the same header and only have minor modified midpipe hangers.

While a 4:1 is traditional on the GS, the 4:2:1 for the GS is really pretty rare but does offer a significant midrange improvement if the Yoshi pipe on my bike is any indication. In addition for anybody considering a GSXR conversion the 4:2:1 improvement in ground clearance makes the hat conversion much more feasible. The 4:2:1 is pretty much standard on today's modern performance bikes.

For this entire class of exhaust the only major divide between 4:1 exhausts is whether the pipes exits to the side or down the center of the bike. The difference is whether the exhaust must be removed to change the oil or not. It might be possible to get the best of both worlds and cover almost this entire range of bikes using a 4:2:1 configuration.

After much searching, I found a stainless 4:2:1 yoshimura exhaust for a 2nd generation GSXR that mounts to my GS (see the pictures). In my mind this is truly the best GS exhaust and would be very marketable if it could be reproduced.

The main issue to deal with is how to configure the header for the mid pipe and can. Making a standard header with different mid pipes to accommodate additional variations in 2 .25"(modern) and 2.5"(period) cans would be most flexible.

I could be persuaded to offer up my Yoshi pipe for making a jig if you are interested. I posted this here so others might comment.

[posplayr]

I have to respectfully disagree. I assume that you are referring to me, maybe you aren't. By saying what I said, I was not trivializing the process. In the end though, I have put a lot of time in to making a set of headers, including modeling a complete engine in Ricardo and designing the header with a 3d Modeling program (Pro/E). I spec'd the design, I cut the tubes, I welded them, I ground the welds, I polished the header, I sourced the coating specialist, I installed them and they worked damn good both on the dyno and in the real world. In hindsight, it wasn't that big of a deal. Most of what I've done wasn't necessary for the kinds of applications that these bikes will see. A person with access to a good MIG/TIG welder a bandsaw and a measuring tape could do it. You don't need an engineering degree. Hell, tack weld the parts and take them to someone else to finish them. A good weld is strong and wont compromise the part in any way no matter how many sections you make it out of. Its a very realistic thing to do for any metal fabricator. Sorry to ruffle your feathers. What I said is based on my experience of actually doing it, not reading about it or hearing about it being done.

Can U dig up some pics?

[Mysuzyq]

Texasgs, thanks for the reply and rough quote. The price appears to be in line with what Rob was quoted, and will end up higher than most members can/will pay, though it will likely be a one-time purchase that should last the life of the bike. Figure about $200 for a nice can, added to the price of the header, and we are almost at the $1000 mark, which is what some specialty Japanese systems (not Yosh) are going for (not including shipping), or the Racefit systems (from the U.K., now marketed in the USA too) with the CF cans are going for. Ultimately, we aren't able to achieve much of a saving going this route......I'm thinking the best overall option seems to be to buy a header in good condition, ceramic coat it, and then have a midpipe bent to accept a modern RS-3 or any slip-on of choice......should still end up costing less than 1/2 of the full SS system, with decent performance and reasonable corrosion protection. Just my $0.02.

Tony.

[drhach]

Can U dig up some pics?

I've been looking. It was a couple of computers ago. . As soon as I find them, I'll post them.

[jwhelan65]

These show up on the board from time to time...

[TheCafeKid]

Guys guys. As I'm sure many of you realize, there is much much more to the headers than jus bending and welding and the like. Different header/midpipe/can combos can have dramatic effects on where and when optimum flow rate,scavenging and maximum power is made. While VH headers probably had alot of reasearch put into them they were more or less designed (at least your standard street pipe/Meg ) were made for practical performance eg Joe motorbike to toss on his machine without questioning weather or not other areas of the rpm ranges would be negatively effected. Midpipes on



these pipes are generally smaller in diameter, as well as in some cases the down tubes themselves. This results, at least as has been experienced by me in many fittings and testing of different headers I've had laying about, in a lively midrange rpm reaction but much less gain in the upper rpm band. A pipe, more inclined to be used on the track, usually have larger midpipes and down pipes. Since revs are usually at the extreme end of the scale in track conditions the design effects those areas. Massive top end rush is the result. One pipe I have (SuperTrapp) with a large pipeset makes my 1100E take off like it was shot out of a cannon from about 6K on. The VH pipe like Joe posted up on the same bike tuned to it resulted in a very punchy midrange ( really nice for standard street riding) but ultimately next to no rush up top. Very flat.
The difference is remarkable and a bit unsettling if you're not planning for it.

Anyway my point is, unless one were planning on more or less copying an already existing design or was highly versed in the physics and philosophy of tuning exhaust (there is sooooo much to it and I fear I've greatly over-simplified it for sake of example) just cutting and bending and welding may or maynot introduce unwanted running conditions and have an overall negative effect on performance. If your overall end diameter doesn't equal or best the combined stock diameter of the pipe you have to compensate for that with other things. If it were that easy, everyone would do it. Lol

[posplayr]

Guys guys. As I'm sure many of you realize, there is much much more to the headers than jus bending and welding and the like. Different header/midpipe/can combos can have dramatic effects on where and when optimum flow rate,scavenging and maximum power is made. While VH headers probably had alot of reasearch put into them they were more or less designed (at least your standard street pipe/Meg ) were made for practical performance eg Joe motorbike to toss on his machine without questioning weather or not other areas of the rpm ranges would be negatively effected. Midpipes on



these pipes are generally smaller in diameter, as well as in some cases the down tubes themselves. This results, at least as has been experienced by me in many fittings and testing of different headers I've had laying about, in a lively midrange rpm reaction but much less gain in the upper rpm band. A pipe, more inclined to be used on the track, usually have larger midpipes and down pipes. Since revs are usually at the extreme end of the scale in track conditions the design effects those areas. Massive top end rush is the result. One pipe I have (SuperTrapp) with a large pipeset makes my 1100E take off like it was shot out of a cannon from about 6K on. The VH pipe like Joe posted up on the same bike tuned to it resulted in a very punchy midrange ( really nice for standard street riding) but ultimately next to no rush up top. Very flat.
The difference is remarkable and a bit unsettling if you're not planning for it.

Anyway my point is, unless one were planning on more or less copying an already existing design or was highly versed in the physics and philosophy of tuning exhaust (there is sooooo much to it and I fear I've greatly over-simplified it for sake of example) just cutting and bending and welding may or maynot introduce unwanted running conditions and have an overall negative effect on performance. If your overall end diameter doesn't equal or best the combined stock diameter of the pipe you have to compensate for that with other things. If it were that easy, everyone would do it. Lol

Josh,
That is why I was offering up my Yoshi 4:2:1 as it is a know quantity and it has been adapted (by me) to a GS1100ED and I know it improved my midrange without giving up much at 8K RPM+ (I don't spend alot of time there and would need a dyno anyway to quantify it).
Personally I would ONLY be interested in a clean 4:2:1. That is what nearly all modern performance bikes have.

I added spigots and modified the mid pipe to fit the ED so any variations to fit another GS750/1000,1100 (which all use the identical V&H pipe) wont make a hill of beans difference.

Wow wouldn't that be a great article. I take my 1166 bike down to the local Motorcycle dyno joint and do separate tests for the Yoshi 4:2:1, The race Yoshi 4:1 and the V&H megaphone. I wonder if it would need to be re jetted; probably not.

Well $300 and a day off ; I'm not really all that interested as I know the answer; the 4:2:1 has the broadest power band.

Bottom line from a business perspective a 4:2:1 stainless pipe for would offer something that even all the vintage pipes dont specifically:

• Improved Ground clearance (how many 4:1 have been bottomed out)
• Oil plug accessibility (I checked the 4:2:1 splits around the drain plug)
• Probable Oil cover Accessibility (no worse than a 4:1)
• More Mid Range power (avoids the 4:1 power flatspot )

The idea of making two different mid pipes is only to accomodate with the 2 1/4" modern slipon standard or the traditional Yoshi can size 2 1/2". A mid pipe to adapt a shortened V&H megaphone might even work; (will take a little work)

Jim

[Mysuzyq]

Bottom line from a business perspective a 4:2:1 stainless pipe for would offer something that even all the vintage pipes dont ...Jim

True, but the real bottom line is economic viability....if header prices end up north of $800 (and that's not including the cost of a decent can that compliments the flow characteristics/advantage of the header design) I suspect the market would be extremely small......I would be extremely surprised if the 15 or more order quota could be met. Really, at this price point, I'd rather spring for a beautiful used 4X1 ti/stainless system from Japan. The 4:2:1 may offer up slightly improved midrange response, but I've sampled quite a few crotch rockets and don't have any complaints about my bike's performance in that area.
Tony.

[posplayr]

True, but the real bottom line is economic viability....if header prices end up north of $800 (and that's not including the cost of a decent can that compliments the flow characteristics/advantage of the header design) I suspect the market would be extremely small......I would be extremely surprised if the 15 or more order quota could be met. Really, at this price point, I'd rather spring for a beautiful used 4X1 ti/stainless system from Japan. The 4:2:1 may offer up slightly improved midrange response, but I've sampled quite a few crotch rockets and don't have any complaints about my bike's performance in that area.
Tony.

Nobody said it was a big market. My only point was how to maximize that small market

[katman]

While VH headers probably had alot of reasearch put into them they were more or less designed (at least your standard street pipe/Meg ) were made for practical performance eg Joe motorbike to toss on his machine without questioning weather or not other areas of the rpm ranges would be negatively effected. Midpipes on

Massive top end rush is the result. One pipe I have (SuperTrapp) with a large pipeset makes my 1100E take off like it was shot out of a cannon from about 6K on. The VH pipe like Joe posted up on the same bike tuned to it resulted in a very punchy midrange ( really nice for standard street riding) but ultimately next to no rush up top. Very flat.
The difference is remarkable and a bit unsettling if you're not planning for it.

The V&H Mega I thought was made to combat the flatspot "can" headers have.

I know I don't do alot of topend hi rev riding on the street so I like the pipe. I would be interested to know the dyno numbers on two pipes since from '86 on the pipes are all smaller down pipes. For the gsxrs anyway.

I would question the "MASSIVE RUSH" which is why a dyno run would be good. I don't know of any gains like that from a pipe alone but could be wrong. The dyno runs on my kats are in the low to mid 130's hp and are anything but flat between 7 and 10k. I can't imagine bolting on a different header and experiencing a massive increase from what is there now.

Of course this is just my opinion. No numbers to back it up.

I was talking to a header guy recently and he was telling me the 4-1 pipe creates a scavenging effect sucking exhaust through the pipe where as the 4-2-1 does not. Anyone heard of that?

[posplayr]

The V&H Mega I thought was made to combat the flatspot "can" headers have.

I know I don't do alot of topend hi rev riding on the street so I like the pipe. I would be interested to know the dyno numbers on two pipes since from '86 on the pipes are all smaller down pipes. For the gsxrs anyway.

I would question the "MASSIVE RUSH" which is why a dyno run would be good. I don't know of any gains like that from a pipe alone but could be wrong. The dyno runs on my kats are in the low to mid 130's hp and are anything but flat between 7 and 10k. I can't imagine bolting on a different header and experiencing a massive increase from what is there now.

Of course this is just my opinion. No numbers to back it up.

I was talking to a header guy recently and he was telling me the 4-1 pipe creates a scavenging effect sucking exhaust through the pipe where as the 4-2-1 does not. Anyone heard of that?

Rob,
There was a discussion on here a while back about exhaust. I did a little research as well and here is what I surmised.

The engine firing of a 4 cycle engine represents a series of pulses (pressure) which is oscillating up and down and to more or lesser extent can be represented by sinusoidal pressure variations.

When a wave of pressure (part of a pulse) hits a change in impedance, there is a tendency for that wave to bounce off of the impedance . This will primary physically occur when 4 pipes join into a single as this is a big change in flow. After the pulse hits the collector a portion goes through and the rest bounces back to the exhaust side of the head. Basically what sets up is a standing wave of pressure variation. The more of a mismatch you have (like going from 4 down to 1) the bigger the reflection and the larger the standing wave ratio.

At some RPM's the standing wave (which is a function of RPM) causes the pressure at the exhaust valve to be at a minimum (pressure) which causes a savaging effect pulling more intake charge than would normally occur. Of course there is an RPM (1/2 of that) where that pressure at the exhaust valve is maximum . In other words just when the exhaust valve is opening the wave that ran down the pipe hit the 4:1 collector is now arriving at maximum pressure just as the exhaust valve is opening. This clearly will inhibit power. So in nominal terms if you want peak scavenging effect and hp at 10K RPM, you will put a flat spot at 5K rpm.

This is described and there are comparison dyno charts in Kevin Cameron,s "Sportbike Performance Handbook". It shows a 93 GSXR 750 with a 4:1 and another chart showing a 97 GSXR 600 with 4:2:1. The 4:2:1 produces a much more linear flow (rising hp with RPM).

I would see the 4:1 as basically a great idea to get racing performance increase from 7-12K rpm above. After all when do racers lug at 5K rpm?

On the other hand 5K RPM his right in the middle of the torque band for street riding.

The following is just my conjecture.

If you think about the problem as "impedance matching", then in order to get the high pressure at the exhaust port to equalize with the atmospheric pressure at the outlet, the "megaphone" shape makes sense as it is gradually transitioning from the small diameter of the collector out to as big as practical to reduce the pressure down to 1 atm.

By providing the more gradual pressure transition, there is a lessor standing wave and more linear power gain with RPM (better for street).

[katman]

Rob,
There was a discussion on here a while back about exhaust. I did a little research as well and here is what I surmised.

The engine firing of a 4 cycle engine represents a series of pulses (pressure) which is oscillating up and down and to more or lesser extent can be represented by sinusoidal pressure variations.

When a wave of pressure (part of a pulse) hits a change in impedance, there is a tendency for that wave to bounce off of the impedance . This will primary physically occur when 4 pipes join into a single as this is a big change in flow. After the pulse hits the collector a portion goes through and the rest bounces back to the exhaust side of the head. Basically what sets up is a standing wave of pressure variation. The more of a mismatch you have (like going from 4 down to 1) the bigger the reflection and the larger the standing wave ratio.

At some RPM's the standing wave (which is a function of RPM) causes the pressure at the exhaust valve to be at a minimum (pressure) which causes a savaging effect pulling more intake charge than would normally occur. Of course there is an RPM (1/2 of that) where that pressure at the exhaust valve is maximum . In other words just when the exhaust valve is opening the wave that ran down the pipe hit the 4:1 collector is now arriving at maximum pressure just as the exhaust valve is opening. This clearly will inhibit power. So in nominal terms if you want peak scavenging effect and hp at 10K RPM, you will put a flat spot at 5K rpm.

This is described and there are comparison dyno charts in Kevin Cameron,s "Sportbike Performance Handbook". It shows a 93 GSXR 750 with a 4:1 and another chart showing a 97 GSXR 600 with 4:2:1. The 4:2:1 produces a much more linear flow (rising hp with RPM).

I would see the 4:1 as basically a great idea to get racing performance increase from 7-12K rpm above. After all when do racers lug at 5K rpm?

On the other hand 5K RPM his right in the middle of the torque band for street riding.

The following is just my conjecture.

If you think about the problem as "impedance matching", then in order to get the high pressure at the exhaust port to equalize with the atmospheric pressure at the outlet, the "megaphone" shape makes sense as it is gradually transitioning from the small diameter of the collector out to as big as practical to reduce the pressure down to 1 atm.

By providing the more gradual pressure transition, there is a lessor standing wave and more linear power gain with RPM (better for street).

Exactly what I was thinking...

[posplayr]

I just made a deal on this Micro Stainless 4:2:1.
It will need some modification to fit the GS, but looks alot like the Yoshi

[posplayr]

another pic