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914World.com _ 914World Garage _ Header sizing 914-6
Posted by: mb911 Dec 27 2015, 02:21 PM
So while my 914-6 oil tanks are being machined I going to start working through my header with heat exhanger design out of stainless.. I do not have non compete on these with m&k so that gives me design freedom.. However I will use similar design process as the m&k/ rarlyl8 design. So my question is 1.5" the most common size or allot of you using 1.625
Posted by: Steve Dec 27 2015, 02:29 PM
Most common aftermarket is 1 5/8" OD for 3.2 and under and 1 3/4" OD for 3.6 motors.
The factory six concours guys will probably stick with the stock 1.5" OD heat exchangers
Posted by: mepstein Dec 27 2015, 03:38 PM
I would like 1 5/8 for my 3.2. I want your first set.
Posted by: Dion Dec 27 2015, 03:48 PM
I'll be in for a set. Would be for a 2.4L Right behind ya Mark!
Posted by: wndsnd Dec 27 2015, 05:25 PM
If these have heat, I would like to see what they would look like. Probably 1 5/8
Posted by: jmill Dec 27 2015, 07:30 PM
From Dempsey's book
2.0-2.4 = 1 1/2 or 1 5/8
2.5-2.8 = 1 5/8
3.0-3.2 = 1 5/8 or 1 1/2 (think he meant 1 3/4)
3.4-3.5 = 1 3/4
3.6-3.8 = 1 3/4 or 1 7/8
Your largest target would be 1 5/8 for 2.0-3.2
Who needs heat? 
Posted by: mb911 Dec 28 2015, 05:49 AM
From Dempsey's book
2.0-2.4 = 1 1/2 or 1 5/8
2.5-2.8 = 1 5/8
3.0-3.2 = 1 5/8 or 1 1/2 (think he meant 1 3/4)
3.4-3.5 = 1 3/4
3.6-3.8 = 1 3/4 or 1 7/8
Your largest target would be 1 5/8 for 2.0-3.2
Who needs heat?
You and i for sure.. I need to come pick up that engine shortly so I can get working on this..
As to what they look like with heat this will be again a little trial and error.. I probably need a true 914-6 bracket to set height for the muffler and put the engine trans assembly together and start mocking up.. They won't look oem but won't look like b&b either..
Mark I will surely put you on the list for the first set..
Posted by: Mark Henry Dec 28 2015, 08:27 AM
1-1/2" up to 2.7
1-5/8" or 1 3/4" for 3.0 and 3.2, stock I'd use the 1 5/8" and use the bigger for HP.
But that said, although there would obviously be a bit of power loss, even a stock 3.2 runs fine on factory heat exchangers with are IIRC only about 1 3/8".
Posted by: JmuRiz Dec 28 2015, 08:28 AM
My 2.7 was spec'd out at 1 5/8 by MSDS.
I'm quite interested in your project!!!
BTW if someone has some SSI 911 heat exchangers and/or some stock 914/6 or the new reproduction units, get them to mb so he can use them for setup 
Posted by: jmill Dec 28 2015, 08:50 AM
I need to come pick up that engine shortly
Come by and get it. It's on an engine stand right by the garage door.
Posted by: Steve Dec 28 2015, 10:30 AM
My 2.7 was spec'd out at 1 5/8 by MSDS.
I'm quite interested in your project!!!
BTW if someone has some SSI 911 heat exchangers and/or some stock 914/6 or the new reproduction units, get them to mb so he can use them for setup
I also ran 1 5/8" MSDS headers on my 2.7. Ran awesome. It was a stock 2.7 with webers.
Posted by: wndsnd Dec 28 2015, 05:27 PM
Is there an accepted ratio between exhaust port size, and header pipe size?
Looking at the chart posted above the 1 5/8 pipe is used for 2.0 to 3.2 head sizes, yet the port sizes vary considerably.
1 5/8 is 41.275 mm.
Exhaust ports run from 32 mm to 38 mm for those engine sizes. I have heard if you oversize, you can kill performance but obviously some oversizing is prefered. What is considered optimal?
Posted by: jmill Dec 28 2015, 05:57 PM
Is there an accepted ratio between exhaust port size, and header pipe size?
I'm no engineer but I'd think cylinder volume & RPM would be more relevant.
Posted by: mb911 Dec 28 2015, 06:25 PM
Is there an accepted ratio between exhaust port size, and header pipe size?
I'm no engineer but I'd think cylinder volume & RPM would be more relevant.
Yes and yes so camshaft could dictate allot. Ssi use to only make one size primary but changed flanges based off engine requirement. I always saw great performance out of 1.5" primary 1.375 id on 2.0-3.0 on 3.2s you have to go 1.625.. I personally liked the 993 heat exchanger the best for this application.. In fact that would be a good fit for 914-6 but useing the Gillette style not bischoff like I preferred for the 911 setup because of flange location and adaption. Though the 993 heat exchanger is not equal length they are 1.625 and are very close to equal length..
I will probably go with 1.625 as my base but I worry about loss of low end torque on the smaller engines
Posted by: mepstein Dec 28 2015, 07:19 PM
Is there an accepted ratio between exhaust port size, and header pipe size?
I'm no engineer but I'd think cylinder volume & RPM would be more relevant.
Yes and yes so camshaft could dictate allot. Ssi use to only make one size primary but changed flanges based off engine requirement. I always saw great performance out of 1.5" primary 1.375 id on 2.0-3.0 on 3.2s you have to go 1.625.. I personally liked the 993 heat exchanger the best for this application.. In fact that would be a good fit for 914-6 but useing the Gillette style not bischoff like I preferred for the 911 setup because of flange location and adaption. Though the 993 heat exchanger is not equal length they are 1.625 and are very close to equal length..
I will probably go with 1.625 as my base but I worry about loss of low end torque on the smaller engines
Smaller engines already have the stock he's. The large engines have been waiting on a solution.
Posted by: mb911 Dec 28 2015, 07:39 PM
Is there an accepted ratio between exhaust port size, and header pipe size?
I'm no engineer but I'd think cylinder volume & RPM would be more relevant.
Yes and yes so camshaft could dictate allot. Ssi use to only make one size primary but changed flanges based off engine requirement. I always saw great performance out of 1.5" primary 1.375 id on 2.0-3.0 on 3.2s you have to go 1.625.. I personally liked the 993 heat exchanger the best for this application.. In fact that would be a good fit for 914-6 but useing the Gillette style not bischoff like I preferred for the 911 setup because of flange location and adaption. Though the 993 heat exchanger is not equal length they are 1.625 and are very close to equal length..
I will probably go with 1.625 as my base but I worry about loss of low end torque on the smaller engines
Smaller engines already have the stock he's. The large engines have been waiting on a solution.
Good point.. Well guess I will have to solve that.. ..
Anyone know what the difference between a 1.7/ 1.8 muffler bracket? I remember they can simply be redrilled but been 15 years since I have done that..
Posted by: jmill Dec 28 2015, 09:45 PM
Smaller engines already have the stock he's.
At $3K a pair.
Posted by: eitnurg Dec 29 2015, 03:40 AM
Many (too many) years ago I had a Euro 3.2 and standard 914 HEs on a rolling road. From memory peak power was down about 20hp and 800 rpm compared to mild steel headers.
Also for a Q&D solution a friend who messed about with engines said a good rule of thumb was the "pipe should be the same size as the valve". Without looking it up I've no idea what that equates to, but at the time the comment was "hmmm, he's not wrong...".
Posted by: Mark Henry Dec 29 2015, 06:32 AM
One thing I haven't seen discussed is the other half of the exhaust equation...what are you going to run for a muffler?
1 3/4" pipes on a stock banana? then you may as well stuck to a smaller tubes anyways.
Zero backpressure then you are likely very loud and may lose some bottom end torque.
Like everything in the high performance engine world there is no perfect combo, everything is a trade off. Too much of a good thing is usually bad for street drivability. Getting the drivability back for the street and you will lose the peek HP.
Hot street with driveability is a balancing act and with this type of engine I'm looking more at torque curve than peek HP.
One thing I was always seeing was peeps building full race tuned engines, then not being happy with the end result, because they only ever drove on the street.
Also here's a rub, in the 90's friend and I built same size 2.0 bug engines (78mm X 90.5). His had 044 big valve head's and mine had ported and polished stock valve heads, his had a w-120 cam and mine the slightly smaller w-110, his a 1 5/8" header and mine a 1 1/2", other than that I'd say everything else was equal. We drag raced (yes illegally) countless times, he never could catch me, I beat him off the line every time. He would be catching up to me, but he could never match my bottom end torque.
Now this is more experience with Type 1 vw performance engines and I build T4 engines with the same premise, but at 2.0 (78X 90.5mm) each cylinder has the same volume as a 3.0/6.*
I always noticed smaller (1 1/2") tube headers provided more bottom end grunt, where bigger tubes gain top end at the cost of the bottom end torque. As many know this is also true with cam selection, mild to wild what you gain with one you lose with the other. Same when added a bit of backpressure with the muffler compared to a megaphone straight out pipe stinger.
Since 95% of the engines I've ever build were for the street, I've always strived for the balance of an acceptable idle (a little loppy is OK as long as it will idle at 900rpm) with good bottom end torque and acceptable top end.
What I'm getting at is a bit of loss in exhaust flow may be worth it, you have to be truthful to yourself as to what are you using the car for.
Racing? you want the biggest baddest straight through loud pipes.
Quiet or semi quiet? with street drivability? Then the muffler is likely killing (at minimum effecting) any larger tube advantage anyways. Plus personally I'd be more interested it bottom end torque then the top end HP.
*Even with VW t1 big valves they're are still smaller valves then /6, etc. I know VW t1 references it's not a true apples to apples example but IMHO and just an FYI I've build a lot of T1&4, plus a few /6 motors, so it's close enough.
Posted by: wndsnd Dec 29 2015, 11:13 AM
Good information, those heads have 40mm exhaust valves, so that would make sense.
Posted by: mepstein Dec 29 2015, 12:02 PM
These. Open pipe. No baffle. No exhaust. Turn the volume up to 11 and piss off the neighbors. 
But i want heat.
Attached image(s)
Posted by: mb911 Dec 29 2015, 12:17 PM
After the headers with heat are done. I will be working with m&k to build a quiet version very similar to the stock internals just out of stainless..
My short list of products and will be introduced in 2016 are oil tanks, oil filter consoles, oil filler necks, headers with heat exchangers, and a quiet muffler.. Most of this I have developed before just for 911s..
Posted by: Steve Dec 29 2015, 12:40 PM
Any idea what the cost will be for 1 5/8" heat exchangers? I am currently running stock 914-6 heat exchanges on a 3.2 motor. I know its choking the motor a bit, but it runs fine.
Posted by: brant Dec 29 2015, 01:24 PM
I can't wait to see them and the cost also
I'll start saving now..
will need one set and love your work!!!
Posted by: mb911 Dec 29 2015, 02:54 PM
Any idea what the cost will be for 1 5/8" heat exchangers? I am currently running stock 914-6 heat exchanges on a 3.2 motor. I know its choking the motor a bit, but it runs fine.
Just a quick costing exercise would be per header 1 burns style merge collector $175, each flange $10, each bend is about $20 along with the heat exchanger which will not look stock but more similar to b&b.. Probably in 200 per heat exchanger in stainless steel and non polished.. I have also considered making heat exchangers for the headers that are already out there in the aftermarket..
I think my target would be 1500 for a set of complete headers/heat exchanger.
Posted by: Mark Henry Dec 29 2015, 03:56 PM
Any idea what the cost will be for 1 5/8" heat exchangers? I am currently running stock 914-6 heat exchanges on a 3.2 motor. I know its choking the motor a bit, but it runs fine.
Just a quick costing exercise would be per header 1 burns style merge collector $175, each flange $10, each bend is about $20 along with the heat exchanger which will not look stock but more similar to b&b.. Probably in 200 per heat exchanger in stainless steel and non polished.. I have also considered making heat exchangers for the headers that are already out there in the aftermarket..
I think my target would be 1500 for a set of complete headers/heat exchanger.
At that price you would have /6 customers lined up around the corner, that is if you can come up with a product/design that works.
Posted by: Travis Neff Dec 29 2015, 04:55 PM
nice price!
Posted by: wndsnd Dec 29 2015, 05:04 PM
Sounding good.
Would a rounder style heater box like the stock design or at least if the tops were rounded tend to stay cleaner?
Posted by: mb911 Dec 29 2015, 05:05 PM
nice price!
I hope I can make it happen the b&b are very simple but cost way to much.. The factory ones are a great design again was at to costly.. If people don't want factory look but want nice design and cost effective then I guess mine will fit the bill
Posted by: mb911 Dec 29 2015, 05:07 PM
Sounding good.
Would a rounder style heater box like the stock design or at least if the tops were rounded tend to stay cleaner?
Yes but then your talking stamping dies $$$$$
Posted by: wndsnd Dec 29 2015, 05:13 PM
Got it.
Posted by: mb911 Dec 29 2015, 06:23 PM
Any feed back on the 914-6 vs 4cyl muffler bracket..??
Posted by: Travis Neff Dec 29 2015, 06:26 PM
914-6 headers and OE heat exchangers can use the 2.0 exhaust bracket, from what I hear
Posted by: mepstein Dec 29 2015, 06:41 PM
Make up something cool from ss. I have an England hanger if you want a pic.
Posted by: Travis Neff Dec 29 2015, 07:17 PM
and by 2.0, I mean the 4 cyl 2.0 bracket
Posted by: Travis Neff Dec 29 2015, 07:18 PM
If you wanted to do something cool, one that would incorporate the muffler straps would be cool
Posted by: Steve Dec 29 2015, 07:24 PM
I'm running factory six heat exchangers, with a 2.0 four muffler hanger. Works fine. I've been running this combo with my 3.2 for over 15 years.
Posted by: JmuRiz Dec 30 2015, 09:10 AM
Good point.. Well guess I will have to solve that.. ..
Anyone know what the difference between a 1.7/ 1.8 muffler bracket? I remember they can simply be redrilled but been 15 years since I have done that..
Here's and old pic from the board:
Looks like making a SS bracket like a 2.0 hanger and/or straps would be a better solution.
Attached image(s)
Posted by: mepstein Dec 30 2015, 09:15 AM
England hanger
Attached thumbnail(s)
Posted by: Mueller Dec 30 2015, 09:23 AM
England hanger
I'd ditch the welded-on stiffener and use dimple dies instead reduce flexing in that part.
Posted by: mb911 Dec 30 2015, 12:45 PM
Looks like I have c.. So the question is the height the same for b and c from mounting on the trans axle to the muffler bolt location so that all I need to do is still new holes in my 1.7, 1.8 bracket..
My method for locating everything is the engine being point a and the bracket is point b that way I I can build from a-b.. So the bracket is really important for mocking up. I will develop something like the 911 has for the finished product.
Posted by: gandalf_025 Dec 30 2015, 02:51 PM
Any chance you can make some simple ones like these in stainless ?
Posted by: mb911 Dec 30 2015, 03:50 PM
Any chance you can make some simple ones like these in stainless ?
Yup and then heat exchangers would be a breeze.
Posted by: mb911 Dec 30 2015, 03:50 PM
Who made this originally?
Posted by: gandalf_025 Dec 30 2015, 04:33 PM
Who made this originally?
Not entirely sure who made them..
They were a backup set of headers for a 914-6 GT .
They were made in the early 70's. I bought them in the mid 70's
They had never been on a car, so.. new when I got them.
they look like they were hand made.
They were part of a big parts stash that got bought by someone I knew.
The Race Team moved and sold off a lot of parts before moving.
I can PM you more details if you like ?
I got this shift rod at the same time, it allows for an early 911 aluminum
case engine to fit in a 914-6 and clear the casting on the bottom of the engine.
Posted by: jmill Dec 30 2015, 04:49 PM
Looks like I have c.. So the question is the height the same for b and c from mounting on the trans axle to the muffler bolt location so that all I need to do is still new holes in my 1.7, 1.8 bracket..
I may have a B laying around. I'll take a look. I'm also interested in a simple exhaust that bolts to a nice 2 outlet muffler. Something that'll make my little 2.2 sound like an IMSA car.
Posted by: jmill Dec 30 2015, 04:55 PM
England hanger
I'd ditch the welded-on stiffener and use dimple dies instead reduce flexing in that part.
Wouldn't help. The part would still flex in between the dimpled holes.
Posted by: wndsnd Dec 30 2015, 04:59 PM
Who made this originally?
Not entirely sure who made them..
They were a backup set of headers for a 914-6 GT .
They were made in the early 70's. I bought them in the mid 70's
They had never been on a car, so.. new when I got them.
they look like they were hand made.
They were part of a big parts stash that got bought by someone I knew.
The Race Team moved and sold off a lot of parts before moving.
I can PM you more details if you like ?
I got this shift rod at the same time, it allows for an early 911 aluminum
case engine to fit in a 914-6 and clear the casting on the bottom of the engine.
GT Racing Headers, in SS with heat, for $1500.00. Now we are talking!
Posted by: mb911 Dec 30 2015, 05:23 PM
Who made this originally?
Not entirely sure who made them..
They were a backup set of headers for a 914-6 GT .
They were made in the early 70's. I bought them in the mid 70's
They had never been on a car, so.. new when I got them.
they look like they were hand made.
They were part of a big parts stash that got bought by someone I knew.
The Race Team moved and sold off a lot of parts before moving.
I can PM you more details if you like ?
I got this shift rod at the same time, it allows for an early 911 aluminum
case engine to fit in a 914-6 and clear the casting on the bottom of the engine.
GT Racing Headers, in SS with heat, for $1500.00. Now we are talking!
I still think I can make it happen for that or darn close
Posted by: mb911 Dec 30 2015, 05:24 PM
Who made this originally?
Not entirely sure who made them..
They were a backup set of headers for a 914-6 GT .
They were made in the early 70's. I bought them in the mid 70's
They had never been on a car, so.. new when I got them.
they look like they were hand made.
They were part of a big parts stash that got bought by someone I knew.
The Race Team moved and sold off a lot of parts before moving.
I can PM you more details if you like ?
I got this shift rod at the same time, it allows for an early 911 aluminum
case engine to fit in a 914-6 and clear the casting on the bottom of the engine.
I definitely interested please more details.
Posted by: Gary Dec 31 2015, 12:03 PM
Any chance you can make some simple ones like these in stainless ?
McMark has a set left over from a -6 install he is doing for me: http://www.914world.com/bbs2/index.php?showtopic=258588. As far as I know he did not sell them before his move.
Posted by: mb911 Dec 31 2015, 02:40 PM
Picked up the engine today thanks John. Going to build a 2x4 stand this week so I can put the engine and the trans on the stand upside down and can build the exhaust as if it were sitting on a bench.. .. Need confirmation that the bracket c is the same as bracket b except for the spacing on the muffler bolt holes..
Posted by: JmuRiz Dec 31 2015, 02:52 PM
They aren't the same, the heights are different for the 1.7/1.8 and 2.0
See the rise in the heat exchangers on the smaller engines:
Posted by: mb911 Dec 31 2015, 03:00 PM
They aren't the same, the heights are different for the 1.7/1.8 and 2.0
See the rise in the heat exchangers on the smaller engines:
That's not good. Now I need a measurement so I can modify what I have to be able to get to work
Posted by: Luke M Dec 31 2015, 05:25 PM
You would need a 914-6/914 2.0 bracket . There's a few different 914 4 styles early to late it changed again IIRC.
Pic shows the 914-6/ 914 2.0 bracket.
Attached image(s)
Posted by: jmill Dec 31 2015, 06:10 PM
OK, I thought I had a couple of 2.0 muffler hangers I could give Ben. I don't. I must have gave them away or put them somewhere I wouldn't lose them.
Ben needs some measurements. Can someone with a 2.0 muffler hanger give him the center to center measurements in the picture below. If a couple of guys pipe in and confirm them, even better.
Attached image(s)
Posted by: Luke M Dec 31 2015, 06:16 PM
OK, I thought I had a couple of 2.0 muffler hangers I could give Ben. I don't. I must have gave them away or put them somewhere I wouldn't lose them.
Ben needs some measurements. Can someone with a 2.0 muffler hanger give him the center to center measurements in the picture below. If a couple of guys pipe in and confirm them, even better.
I have one off my 6. I'll go out and measure it in a few.
20" c to c on header flange mount, 5" c to c on trans mount holes, 6 1/4" c to c from trans mount down to center flange line.
Posted by: mb911 Jan 4 2016, 03:34 PM
OK, I thought I had a couple of 2.0 muffler hangers I could give Ben. I don't. I must have gave them away or put them somewhere I wouldn't lose them.
Ben needs some measurements. Can someone with a 2.0 muffler hanger give him the center to center measurements in the picture below. If a couple of guys pipe in and confirm them, even better.
I have one off my 6. I'll go out and measure it in a few.
20" c to c on header flange mount, 5" c to c on trans mount holes, 6 1/4" c to c from trans mount down to center flange line.
Thanks for the info. I will mod my mount and start mocking up parts.. I have to make a hard decision on these.. I really wanted to use a burns style collector as they are so nice but that could drive the price up another 450 in cost over just a simple collector like you see so often. I looked at headers by eds website as they offer a bunch of options but I can buy everything locally for about the same price and I can locally source all the flanges as well.. So to meet my target of 1500. It looks like it will be the simplier collector..
What is everyone's thoughts on this?
Posted by: wndsnd Jan 4 2016, 04:47 PM
Design and build the best performance and quality product you can at a competitive price. Offer two sizes, heat and no heat. My .02
Posted by: Eric_Shea Jan 4 2016, 06:38 PM
It began to rain in Baton Rouge and it continued that night, through the next day in New Orleans and into Florida.
I was excited to be able to pull my red lever on the center tunnel and crank the upper dash lever to the right, middle to the left and lower to the right and clear off my windshield in a few seconds.
Heat isn't always for heat... something to consider next time you say you don't need heat. 
Posted by: jd74914 Jan 4 2016, 09:21 PM
Thanks for the info. I will mod my mount and start mocking up parts.. I have to make a hard decision on these.. I really wanted to use a burns style collector as they are so nice but that could drive the price up another 450 in cost over just a simple collector like you see so often. I looked at headers by eds website as they offer a bunch of options but I can buy everything locally for about the same price and I can locally source all the flanges as well.. So to meet my target of 1500. It looks like it will be the simplier collector..
What is everyone's thoughts on this?
By simpler collector do you mean a formed collector vs. the nice welded ones with inner guide that Burns sells?
Posted by: Cairo94507 Jan 4 2016, 11:13 PM
I would love a set of SS headers for my 3.2 with heat exchangers....I agree with wndsnd, design the best and offer with and w/o heat.
Posted by: porschetub Jan 5 2016, 03:14 AM
It began to rain in Baton Rouge and it continued that night, through the next day in New Orleans and into Florida.
I was excited to be able to pull my red lever on the center tunnel and crank the upper dash lever to the right, middle to the left and lower to the right and clear off my windshield in a few seconds.
Heat isn't always for heat... something to consider next time you say you don't need heat.
,its about defrost but really that's the wrong term in a warmer climate,you still need something to move air over the inside of the screen regardless of where you live.Posted by: mb911 Jan 5 2016, 06:11 AM
Thanks for the info. I will mod my mount and start mocking up parts.. I have to make a hard decision on these.. I really wanted to use a burns style collector as they are so nice but that could drive the price up another 450 in cost over just a simple collector like you see so often. I looked at headers by eds website as they offer a bunch of options but I can buy everything locally for about the same price and I can locally source all the flanges as well.. So to meet my target of 1500. It looks like it will be the simplier collector..
What is everyone's thoughts on this?
By simpler collector do you mean a formed collector vs. the nice welded ones with inner guide that Burns sells?
Yes and no.. It would still be a welded assembly but much more like a formed collector..
Posted by: JmuRiz Jan 5 2016, 01:19 PM
FYI I was looking at Armondo's 914/6 GT site and saw this picture of the Monte Carlo 914/6 GT's heat exchangers...never seen anything like them before. It must have been so they could run defrost etc at the rally:
http://www.pbase.com/9146gt/image/41939268
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Posted by: jd74914 Jan 5 2016, 01:42 PM
By simpler collector do you mean a formed collector vs. the nice welded ones with inner guide that Burns sells?
Yes and no.. It would still be a welded assembly but much more like a formed collector..
I think I know what you're talking about but do you have a picture or link handy? I'm visualizing the collectors you can readily make with a jig in a bandsaw/chop saw like these.
Posted by: Justinp71 Jan 5 2016, 02:50 PM
Another option to heat exchangers is seat warmers. I plan to do that when I purchase new seats... actually I prefer them over heat. But it also doesn't normally get colder than 50f here in Cali.
Posted by: mb911 Jan 5 2016, 03:32 PM
By simpler collector do you mean a formed collector vs. the nice welded ones with inner guide that Burns sells?
Yes and no.. It would still be a welded assembly but much more like a formed collector..
I think I know what you're talking about but do you have a picture or link handy? I'm visualizing the collectors you can readily make with a jig in a bandsaw/chop saw like these.
Yes exactly
Posted by: mepstein Jan 5 2016, 06:22 PM
Another option to heat exchangers is seat warmers. I plan to do that when I purchase new seats... actually I prefer them over heat. But it also doesn't normally get colder than 50f here in Cali.
9 degrees this morning.
Posted by: jd74914 Jan 6 2016, 12:32 PM
I think I know what you're talking about but do you have a picture or link handy? I'm visualizing the collectors you can readily make with a jig in a bandsaw/chop saw like these.
Yes exactly
Cool. For the $450 it's a no brainer to me at least to go this way.
Posted by: wndsnd Jan 10 2016, 01:31 PM
Updates?
Posted by: mb911 Jan 10 2016, 01:36 PM
Updates?
Sorry been finishing the oil tanks up this is project number 2. I will be welding the tanks starting this coming weekend so then headers will happen.
Posted by: wndsnd Jan 10 2016, 02:15 PM
Watching both keenly!
Posted by: mb911 Mar 14 2016, 01:46 PM
Well I have refined the oil tank process so I should be moving on to this project shortly though I don't know when this will be done thinking another 6 weeks before I get a good handle on them
Posted by: JmuRiz Mar 14 2016, 01:50 PM
Sounds good to me, 6 weeks seems pretty quick to me (I'm a procrastinator)
Posted by: 396 Mar 14 2016, 07:13 PM
By simpler collector do you mean a formed collector vs. the nice welded ones with inner guide that Burns sells?
Yes and no.. It would still be a welded assembly but much more like a formed collector..
I think I know what you're talking about but do you have a picture or link handy? I'm visualizing the collectors you can readily make with a jig in a bandsaw/chop saw like these.
Yes exactly
Well, I'm happy that your oil tank project is finally in production.
Now back to the exhaust. I know the main paradigm is equal length headers.
Are you going with this same mind set? I'm wondering if you have access for some dyno test on a stock engine vs say George's European headers that have been around for years - especially since the header is currently at the design stage.
Good luck with your new project.
Posted by: mb911 Jul 8 2016, 10:39 AM
So this project is going to start soon but I have been thinking maybe what the real market would be to make the heat exchanger kits for current headers?
So for an example I could make them for bursch or Georges etc as to not reinvent the wheel..
What does the brain trust think about that ?
Posted by: wndsnd Jul 8 2016, 11:00 AM
I would consider that...
I am dreading late Fall...
Posted by: JmuRiz Jul 8 2016, 01:31 PM
If they work with Marty's (MSDS) headers, I'm game....think they'd work well (produce good heat) with his ceramic coated headers?
If not, I'll just get a whole header/heater box setup from you
Posted by: gereed75 Jul 8 2016, 02:13 PM
I actually think the idea of a heat plenum that would fit to the existing header choices to be a good idea. As you say, why reinvent the wheel. And all the folks out there with the Bursch headers (I think those are the most common after market ones out there) would have the option of adding heat to there existing headers for way less than an all new set.
I would also suggest looking at a very abbreviated design. My stock set with the "full metal jacket" treatment makes lots of heat.,, more than needed except maybe in the most extreme situations and who among us is out driving their sixes at zero degrees??
The aviation style "heat muffs" are much smaller ( https://www.aircraftspruce.com/pages/ep/carbheat/homebuildersheatmuffs.php ) and the single one in my plane makes a lot of heat. Besides price, the biggest benefit might be that a smaller, well engineered muff would allow for a lot more room to adjust valves. I have not attempted a valve adjustment with the stock HE's in place (is it even possible??) but was able to do one with Bursch headers in place.
What say the masses 
??
Posted by: mb911 Jul 8 2016, 02:32 PM
What I would need is a set to model off of. Anyone have a pair they want to loan me and I will make a set of heat exchangers for them?
Posted by: mb911 Jul 8 2016, 02:32 PM
I actually think the idea of a heat plenum that would fit to the existing header choices to be a good idea. As you say, why reinvent the wheel. And all the folks out there with the Bursch headers (I think those are the most common after market ones out there) would have the option of adding heat to there existing headers for way less than an all new set.
I would also suggest looking at a very abbreviated design. My stock set with the "full metal jacket" treatment makes lots of heat.,, more than needed except maybe in the most extreme situations and who among us is out driving their sixes at zero degrees??
The aviation style "heat muffs" are much smaller ( https://www.aircraftspruce.com/pages/ep/carbheat/homebuildersheatmuffs.php ) and the single one in my plane makes a lot of heat. Besides price, the biggest benefit might be that a smaller, well engineered muff would allow for a lot more room to adjust valves. I have not attempted a valve adjustment with the stock HE's in place (is it even possible??) but was able to do one with Bursch headers in place.
What say the masses
??Heat muffs might be a good option.
Posted by: gereed75 Jul 8 2016, 02:58 PM
I have an old set of what I think are Burschs that I would lend out for the cause. I will post some pics and maybe someone could confirm what they are.
I am not a good candidate to beta test the muffs. Got my stock HE's on and they are not coming off any time soon!!
Like I said, one heat muff on the plane makes good heat in a very drafty, un-insulated cockpit. I am sure a left and right in a 914 would be way toasty.
Posted by: Perry Kiehl Clone Jul 8 2016, 11:26 PM
I tried to get factory 6 HE's reproduced about 16 years ago. Dansk told me the original factory tooling had been scrapped, and they weren't interested. I even shipped a set of factory 6 boxes round trip Europe.
I looked into modifying 3.2 and 3.0 factory boxes, which I think still might be a viable option, but I just dropped the whole idea and started collecting as many 914-6 exhausts as I could get my hands on
From the research I've done on this, I'd suggest the following:
The factory did an excellent job designing the 914-6 exhaust system so, you may want to consider replicating the factory boxes as close as you can. They flow really well and the primaries are close to equal length. This is why you can have a 3.0 or 3.2 with the factory boxes, and it doesn't really feel totally choked. Why reinvent the wheel?
Do not produce a product that has weld seams inside the heat collector shells. You will not find a single factory Porsche heat exchanger with welds in the collector shell, and for good reason.
Posted by: mb911 Jul 9 2016, 05:58 AM
Agreed I made hundreds of sets of headers for rarlyl8 with my other business and was bound by there designs. Now I am not. I really think the bigger market is to make heat exchangers for current header options out there.
Posted by: Perry Kiehl Clone Jul 9 2016, 07:53 AM
You can't make heat exchangers out of mild steel, there's a high probability that it will cause carbon monoxide poisoning at some point in the future.
All Porsche exhausts since the 70's have stainless alloy tubing and mild steel shells, or all stainless. The newer the car the higher quality stainless to the point where it's all stainless. The reasoning on the boxes with mild steel shells is that they would go bad long before the tubing.
In the early development of the 911 the factory exhaust systems had porosity problems inside the heat collectors that failed and caused carbon monoxide poisoning. Subsequently they changed in how they made those.
Posted by: mb911 Jul 9 2016, 08:07 AM
with the 911 market we made the heat exchangers out of aluminum and made them So they can be removed for inspection or replaced from damage. I have an extensive background in in Porsche exhaust ala former owner and designer of m&k exhaust and previous to that I worked in aviation building products for companies like aircraft spruce, the wag aero group, leading edge air foils etc. That said I thinking a removable solution would be attractive to folks that already own headers that work for them.
Ultimatly stainless over stainless preferably 321 would be the best solution to any cracking, porosity issues along with a back purge..
I say we try one set up
Posted by: mb911 Jul 9 2016, 12:36 PM
Another thought I just had as I was looking at my 2.4 on the stand that it has 993 heat exchangers which can be purchased for about 350 a set that they could be a solution. Yes not equal length but a pretty nice design large primaries, excellent heat exchangers , all stainless construction.. By the time you rotate flanges and make extensions total investment of under 1k and very little negatives.
Posted by: mepstein Jul 9 2016, 01:39 PM
Another thought I just had as I was looking at my 2.4 on the stand that it has 993 heat exchangers which can be purchased for about 350 a set that they could be a solution. Yes not equal length but a pretty nice design large primaries, excellent heat exchangers , all stainless construction.. By the time you rotate flanges and make extensions total investment of under 1k and very little negatives.
I wonder if I have an extra set in the shop?
Posted by: bahnzai Jul 9 2016, 01:52 PM
Ben,
I have a factory set of 914-6 exhaust I will loan you for the build up. PM me your shipping address and contact info.
Thanks
Posted by: Perry Kiehl Clone Jul 9 2016, 04:51 PM
Another thought I just had as I was looking at my 2.4 on the stand that it has 993 heat exchangers which can be purchased for about 350 a set that they could be a solution. Yes not equal length but a pretty nice design large primaries, excellent heat exchangers , all stainless construction.. By the time you rotate flanges and make extensions total investment of under 1k and very little negatives.
That's exactly what I thought with the 3.2 style, but I'm sure the 993's are better in terms of performance.
Posted by: mb911 Jul 9 2016, 07:49 PM
Way better . This was a common upgrade for 3.2 cars when I owned m&k exhaust. Brian does not do them anymore because he doesn't own those fixtures.
Posted by: 396 Jul 10 2016, 12:19 AM
Way better . This was a common upgrade for 3.2 cars when I owned m&k exhaust. Brian does not do them anymore because he doesn't own those fixtures.
Quick question, if Brian doesn't have the fixtures, who does?
Especially if someone wanted a set done?
Posted by: mb911 Jul 10 2016, 05:18 AM
I do.
Posted by: JmuRiz Jul 10 2016, 06:43 PM
Interesting about the 3.6 heat exchangers...Scotty said 3.2 are too much work to be worth it on a 914, not sure if he's had a set of 3.6 to play with.
I have a new set of MSDS headers if you need a set to fab HE prototypes.
Posted by: mb911 Aug 21 2016, 02:22 PM
Quick update as I work one the Gt steel rocker flares I am having a friend start drawings and fixtures for the header and heat exchangers based off of the original ones but going 1-5/8" instead. Heat exchangers will be similar to stock as far as shape but will be fabricated.. Once we have a sample to show people we will start a group buy..
Posted by: Eric_Shea Aug 21 2016, 04:05 PM
(2) Pair please.
Posted by: restore2seater Aug 21 2016, 06:08 PM
Any estimate on GB cost?
Posted by: raynekat Aug 22 2016, 12:36 AM
I'm interested in a set of 1-5/8" heat exchangers for sure.
Posted by: mb911 Aug 22 2016, 05:36 AM
Target for group buy is 1500.. I will firm this up this week..
Posted by: JmuRiz Aug 22 2016, 08:04 AM
OOOO, exciting stuff. Are you going to have O2 sensor bungs?
They are always a plus when tuning.
I guess I need to add some more funds to save towards.
Posted by: mb911 Aug 22 2016, 03:23 PM
I can do o2 bungs no issue at all. As I organize the group by I am thinking I will do a deposit as many times when I make things people say they want them and then they back out. This was the case with the oil tanks.. Moving forward that won't happen again ☺.. I will propose 1/3 down but I am thinking that based off of numbers we may go over the 10 units and if that is the case I will discount more off.. I want to get these launched and keep them in the market as a go to staple for 6s..
As I said drawings are being made right now and fixtures shortly after. They will be shaped as the original s but won't be stamped like them.
Posted by: raynekat Aug 22 2016, 07:34 PM
Will happily put down $500 for a set of these.
Posted by: mb911 Aug 23 2016, 01:34 PM
As soon as I finalize price I will open it to a group buy maybe a separate thread??
Posted by: Steve Aug 23 2016, 02:14 PM
I'm definitely interested.
Posted by: mb911 Aug 23 2016, 02:56 PM
Great the more people interested the better.
Posted by: mb911 Aug 24 2016, 05:38 AM
Another update.
Fixture design is underway and should start to be assembling fixture in the next couple of weeks.
1st unit is probably 2 months out as we wait for laser cuts and deal with current work load.
1st units start shipping eta 4 months if not sooner.
Group buy will be 1500 per set plus shipping. After group buy the sets will sell for 1900.
Those interested please pm me so you can get on the list. I do realize you don't see anything yet but I promise you that they will look great. For a snap shot of what I have done in the past look at m&k Exhaust..com as this is the company I use to own and design all of the products. I know I mentioned that already but for the new folks.
Posted by: mb911 Aug 24 2016, 06:01 PM
Looks like 8 sets spoken for 2 more spots and I will close the initial offering.. "
Side note I can make a combo package on oil tanks and heat exchangers as well to save a little money as well.
Posted by: mb911 Aug 25 2016, 02:32 PM
Those that pmd I will print out your pms and send you some information shortly as far as address and how to put a deposit down etc. I will be updating as progress is made.. I will be looking for deposits in a couple of weeks for those in so still time for some of you. To get on board.
Posted by: Jeffs9146 Aug 25 2016, 05:18 PM
PM Sent!
Posted by: mb911 Aug 30 2016, 05:41 AM
Making6 progress.. Hopefully start mocking up fixtures this week. I will post pictures as we work through them.
Posted by: mb911 Sep 6 2016, 01:46 PM
Fixtures are making progress though had this to finish 1st.. I will have pictures this week of progress and reaching out for deposits by the end of the week.
Posted by: jim912928 Sep 6 2016, 08:24 PM
Im also interested
Posted by: mb911 Sep 11 2016, 08:03 AM
Sorry for the delay on an update.. Was a busy short week and I was working on a customer's 911 engine so did not get much done.. I promise pictures this week but with fall coming quickly I want this 911 out of my shop.. I will being taking deposits this week.
Posted by: mb911 Sep 20 2016, 03:16 PM
Just an update fixtures are getting there.. The bends have been ordered and will have something to show by Sunday.. I promise but it will be an in progress picture..
I will then start taking deposits.
Posted by: mb911 Sep 25 2016, 05:31 PM
Making progress.. Will start a group buy thread shortly and will contact all of you that have emailed and pmd me for down payments
Posted by: mb911 Sep 25 2016, 05:36 PM
Oh and I should say the design is a copy of original locations of all bends.
Posted by: mb911 Sep 26 2016, 04:31 AM
And another
Posted by: mepstein Sep 26 2016, 04:56 AM
That looks awesome. I can't wait.
Posted by: Cairo94507 Sep 26 2016, 06:36 AM
Oh those are looking very very nice.....
Posted by: mb911 Sep 26 2016, 06:56 AM
Here is the updated thread with all the group buy information on it.
http://www.914world.com/bbs2/index.php?showtopic=295282
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