The slots will be welded and ground and invisible when Im done. I have never gotten the hang of shrinking metal. Every time I hit it with a hammer it gets bigger making the problem I was trying to solve worse, so I just cut and weld. There are no plans for any kind of anti-reverse anything up at the engine end. The length of the port is part of the tuned length of the pipe so adding any type of anti-reversion anything would just put the pips out of tune. Vince at Burns stainless did the header design for me and Im honestly just doing what he told me to do as he has a reputation for being right. Something interesting here that may have gone unnoticed is that these pipes are really close to the stock exhaust port size. I had to grind and weld the bajesus out of the intake side to get it large enough to feed this engine taking the flow from 90 to 155 but the stock exhaust ports appear to be the correct size for this application as is .meaning they are just a tad large(about 30-40% oversize) for a stock engine. Good for me because its about the 1 thing I dont need to work on but not so good on a stock engine.
Just thinking out loud, what about making a dummy header flange out of some thick scrap metal and cutting it in half on the horz center line and use the two pieces like a die in your press to shape the end of the tubing for the header flange? You could weld a little base on the pieces to keep them from just flopping around on the press. If you heat the end of the pipe up first it might even shrink it a little? You could even make a little plug for the inside of the tubing to keep it from crimping in.
ok, I've only built flat-4 headers (poorly!), but I had a thought... maybe you can some CNC stubs made to adapt? When I screwed it up, I got a set of stubs like these for the Porsche 914 motor. http://www.tangerineracing.com/ExhaustComponents.htm
Trust me, m ke's got a rockin' brain, and better hands. Mark's got it handled, been watching him for years. When the headers are done they will look like Ferrari F1 constructors award work,... maybe better.
I mention the reversion dams again because you bring up the point about oversized ports especially in light of a stock Ferrari engine.One could assume their use, you could weld them up so they are more efficient and smaller for the stock application and use them. This could work in your favor and not need to touch the port. Do you have enough room to open the tube an additional 1/4 inch ...1/8 inch+ on each side (all the way around) since you acknowledge that the ports are too large for a stock engine you could make these ports work with reversion dams by increasing your tube diameter only at the flange. Ferrari has never optimized every trick in the book as its usually unnecessary for example why doesn't the 308 have a V12 in it? They say most exhaust ports are always too large for most applications even from the factories witness 3 intakes vs 2 exhausts even on the 355 or Yamaha heads not quite a 3:2 ratio since diameters are a bit different, but, finally a utilization of the correct theory. Where the tubing ID is larger than the port so the face of the of the head acts as a stepped hole or in your case where you say the port is right on then you would enlarge the tube end so its diameter is larger than the port. The only reason I ask about the reversion dam is because in many motors the purpose of the header is so that each successive exhaust pulse tends to help the next one along sucking it as it were, but where the pulses are spread apart and each pulse stops for that nanosecond before the next pulse coming behind it arrives in the same tube the gas has a tendency to back up(reverse....Backdraft) and when it hits the "lip at the exhaust port / flange it prevents an interruption of the flow in the port itself. this tendency to back up is lessened when each tube is being extractedby the next pulse or so the so the theory goes. I got to watch and hear about the myriad of setups and testing of 4 into 1 headers and 3 into 1 or individual "stinger" pipes and "expansion chamber" setups on 4 and 2 strokes back in the day late 70's and 80's when a lot of dyno testing was done on AMA "Superbike" motorcycles with small motors(compared to here) and small increments were always being reached for. However, in your case you are not pairing (maybe or not ? you would have to do a study on the firing order vs. the pulsing) or coupling of cylinders together and the required lengths of the tuned headers but you are stuck with 4 sets of 3 tubes each....... the result...... is what it is........ or did Burns do all this for you?. Exhaust gas science was a big deal, I've even seen the GM documentaries where they made glass headers so they could introduce smoke into them to study the flow and shapes and lengths and /or watch exhaust fire course thruout elaborate systems. I believe there is a whole area here being skipped over for convenience (or necessity's) sake. In light of all the other nuances being made on this project its possibly only slightly premature. How many years did we labor under the notion "Port and polish" until someone realised that polishing a port wasn't helpful but that a specific texture mattered to the fuel. I think this might be your first best effort at the exhaust because the only real way to know if they will work is on the dyno after you have a running engine, granted this will fit and work wonderfully, I suspect, but once that parameter is established there is quite a bit of fudging that might be called for after you get used to the massive horsepower it will produce (and you will ). But for example in a some engines the ideal pipe is a Tri Y or on others 4 into 2 into 1 pairings. The results do differ and for each setup there is a clear winner and where you have tried to maximize everything else in this engine I'm suggesting that in the likelihood of you not being able to pair cylinders ideally, might not the reversion dams be considered because of the interruption of flow, but its only theory ?. In your case instead of stuffing what you have into a marginally small flange hole maybe opening the hole up and enlarging the tube diameter is easier to open (to stretch) the tube up than close it down, and actually help at the same time?. Have you tested any reversion dam ideas on your flow bench? I can see the difficulty being that you can't pulse the air on the flow bench but are getting total flow numbers...an average. A simple test might tell whether it has an effect either way on total flow ...as for an extracting test that's another difficulty? Maybe I'm just frustrated because you are being given so few choices due to space just to get it all together, for ex. 180 degree crank and spaghetti headers over the top of the engine intermixed with an as yet unknown (finalized) injection system. Main problem is so few have been able to mess with Ferrari engines whereas if it were a domestic engine thousand have tried and conjured every trick in the book. We've only begun to scratch the surface with Ferrari. Sorry, Just too curious to know when to stop. Ross RVIDRCI "Trust me, m ke's got a rockin' brain, and better hands. Mark's got it handled, been watching him for years. When the headers are done they will look like Ferrari F1 constructors award work,... maybe better." Of that I have no doubt, It already shows. Ross
I mention the reversion dams again because you bring up the point about oversized ports especially in light of a stock Ferrari engine where they could be made to work. To make the ports work for reversion dams you would weld them up so they are more efficient and smaller for the stock application. This could work in your favor and not need to touch the port, since you acknowledge that the ports are too large for a stock engine. Do you have enough room to open the tube an additional 1/4 inch ...1/8 inch+ on each side (all away round) here?. Ferrari has taken a long time to optimize every trick in the book as its usually unnecessary for example why doesn't the 308 have a V12 in it? They say most exhaust ports are always too large for most applications even from the factories witness 3 intakes vs 2 exhausts even on the 355 or Yamaha heads not quite a 3:2 ratio since diameters are a bit different, but, finally a utilization of the correct theory. Where the tubing ID is larger than the port so the face of the port outlets of the head acts as a stepped hole or in your case where you say the port is right on then you would enlarge the tube end so its diameter is larger than the port. The only reason I ask about the reversion dam is because in many motors the purpose of the header is so that each successive exhaust pulse tends to help the next one along sucking it as it were, but where the pulses are spread apart and each pulse stops for that nanosecond before the next pulse coming behind it arrives in the same tube the gas has a tendency to back up(reverse....Backdraft) and when it hits the "lip at the exhaust port / flange it prevents an interruption of the flow in the port itself. I got to watch and hear about the myriad of setups and testing of 4 into 1 headers and 3 into 1 or individual "stinger" pipes and "expansion chamber" setups on 4 and 2 strokes back in the day late 70's and 80's when a lot of dyno testing was done on AMA "Superbike" motorcycles with small motors (compared to here) and small increments were always being reached for. However, in your case you are not pairing (maybe or not ? you would have to do a study on the firing order vs. the pulsing) or coupling of cylinders together and the required lengths of the tuned headers but you are stuck with 4 sets of 3 tubes each....... the result...... is what it is........ or did Burns do all this for you?. Exhaust gas science was a big deal, I've even seen the GM(?) documentaries where they made glass headers so they could introduce smoke into them to study the flow and shapes and lengths and /or watch exhaust fire course thruout elaborate systems. I believe there is a whole area here being skipped over for convenience (or necessity's) sake. In light of all the other nuances being made on this project its possibly only slightly premature. How many years did we labor under the notion "Port and polish" until someone realised that polishing a port wasn't helpful but that a specific texture mattered to the fuel. I think this might be your first best effort at the exhaust because the only real way to know if they will work is on the dyno after you have a running engine, granted this will fit and work wonderfully, I suspect, but once that parameter is established there is quite a bit of fudging that might be called for after you get used to the massive horsepower it will produce (and you will ). But for example in a some engines the ideal pipe is a Tri Y or on others 4 into 2 into 1 pairings. The results do differ and for each setup there is a clear winner and where you have tried to maximize everything else in this engine I'm suggesting that in the likelihood of you not being able to pair cylinders ideally, might not the reversion dams be considered because of the interruption of flow, but its only theory ?. In your case instead of stuffing what you have into a marginally small flange hole maybe opening the hole up and enlarging the tube diameter is easier to open (to stretch) the tube up than close it down, and actually help at the same time?. Have you tested any reversion dam ideas on your flow bench? I can see the difficulty being that you can't pulse the air on the flow bench but are getting total flow numbers...an average. A simple test might tell whether it has an effect either way on total flow ...as for an extracting test that's another difficulty? Maybe I'm just frustrated because you are being given so few choices due to space just to get it all together, for ex. 180 degree crank and spaghetti headers over the top of the engine intermixed with an as yet unknown (finalized) injection system. Main problem is so few have been able to mess with Ferrari engines whereas if it were a domestic engine thousand have tried and conjured every trick in the book. We've only begun to scratch the surface with Ferrari. Sorry, Just too curious to know when to stop. Ross RVIDRCI "Trust me, m ke's got a rockin' brain, and better hands. Mark's got it handled, been watching him for years. When the headers are done they will look like Ferrari F1 constructors award work,... maybe better." Of that I have no doubt, It already shows. Ross
He could have, but then he should have swapped the heads to the other side and have the exhaust inside the V. Is it too late for that?
I was thinking along the same lines, since this operation still needs to be repeated 11 times. Maybe an outer shape and a tapered plug than can be forced in? Or a halved outside shape forcing the pipe around a plug. It would eliminate the slits, which are somehow un-elegant.
Both ideas are good. I hadn't thought of machining adapter but I considered a forming mandrel as well as taking the tubes to an exhaust shop to have the ends swaged a bit then form ing them. Honestly though to slit, form, weld, grind is well under 15 minutes per tube so I just didn't see the point in investing time in anything else. I think I'm just going to cary on and get it done. It's the collectors I'm a little scared of....they all appear to happen in turns which makes keep equal lengths a tad difficult. I have a coulpe ideas I'm noodling though so we'll see what I try in about a week but I may need to make some forming tool for this part.
A lot of thoughts here. I have never messed with any kind of reversion dam. I remember reading about them in the 80s but then they seem to have gone away as I've never actually seem a set of headers that had them as far as I could tell anyway. On my header layout the primaries as just 21" long so no kind of cross bank mixing is possible, there just isn't enough tubing to make it happen. The good news is though that there shouldn't be any need. Like the V8 run at 2 4cyl engines, the V and flat 12 engines run as 2 6 cyl engines so all the cylinders timed in anyway as you would want to have cross-talk in the headers are on the same side of the engine and on the 12s the ones you really want talking all right next to each other. The layout and firing order of the 12 leads to 3 options 6-1, 3-1(4 pipe out), 6-2-1 the later being the one I'm building at the recommendation of Burns, Burns has a header design software they have been working with and improving for years the has been show to be pretty good at getting you very close to the design that works best on the dyno on the first try. The software does not let you see what each option will do, it simply spits out the specs for the system that will work best. Im doing everything the way Burns suggested with the exception of an X pipe because there is just no practical way to do that and their feeling was the gain would be small. On the primary size 1.75 is what Im using and is really the smallest I can go without the tubes becoming a significant flow restriction. The stock port exist the head at about a 1.69 effective dia so again, 1.75 is a good match up and the smooth transition allows the port to become a primary tube extension. Ill built it and it will be what it is. Im sure it will not be the absolute best but hopefully it will work pretty well. Maybe after its been running a couple years Ill be motivated to try tuning the exhaust in search of the last few hp, but for now done is my main concern I think this project is dragging
Hytech makes headers with anti-reversion chambers. Here is a tri-y set made for a Honda with the anti reversion chambers. Image Unavailable, Please Login
That is a very strange set of headers. It looks like I'm seeing 1-3, 2-4 pairede up instead of the normal 1-4, 2-3 pariring.
That's how John makes that particular header. Hytech has a reputation in the Honda tuning circles as making lots of power AND torque. Depending on the modifications done to the engine, it isn't unheard of for power gains of 15-20 hp to the wheels, and that's on a 4-banger.
He also does most of the Formula Atlantic headers and even my turbo charged hydrogen fueled Prius headers
Yes does seem odd, and why not just 4 into 1? ... which the Atlantic surely would be because nobody worries about torque with a dedicated race car, HP is everything. Pete
Tonight was give and take. I decided I hadn't left enough room for a decent collect so I re-did the first pipe again bumping the end about 3 inches to the left. When I went to full weld it I realized the solar flux needs to be mixed with methanol and I dont have any. So I moved on to pipe # 2 which seemed to come out just fine. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
+1, and they are actually equal length . Too many times on sites like these people make exhaust systems and they are very obviously unequal length ... why bother making them then?. It just takes longer to make them equal and then you get the gas safely routed to where you want it and you get the performance benefit. Such a waste of time if not equal ... Pete
It didnt occur to me that the hardware store wouldnt carry methanol, butg they doent and it was too late to order on-line and have it ship today so it will be Thur I guess before I have it. Oh well. I might have enough parts to hook up a purge line instead of using the flux so I can get welding tomorrow Ill have a look at that later. A little more progress tonight. Pipe 3 is tacked up and ready to weld. The new 1 ¾ header tubes are quite a bit bigger looking than the stock 1 ½ tubes and a lot less rippled too. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Looking very nice Mark. It's probably the angles in the pictures, but I don't see how you are going to weld 100% around some of those joints unless you disassemble / weld / reassemble. Is that your plan?
You are correct. Only the center tube is tack welded to the flange. The end tubes are currently held with visegrips so I can easily pop them off, weld all the tube seems then put then back in place and do the flange welds. I can't weld the tubes yet because I don't have the methanol to mix up the solar flux or the correct fittings to set up a purge line.....poor planning on my part although this was probably a good way to do it even if it wasn't on purpose, I did change the first tube 3 times before I decide I was happy with it.
Mike, not questioning your methods... just curious as to your choice to use a flux on your joints? Rick
You may know this already, but when you weld stainless steel the metal on the back side of the weld grows black oxide mountain looking things which are not very good for flow if they are inside a header tube. The traditional solution is to purge the inside of the pipe with argon to get rid of the oxygen and that leaves the weld areas inside the tube looking about as good as the outside. The header tubing places all sell a product called solar flux (which it turns out needs to be mixed with methanol before you can use it) that you bush inside the tube at the weld zone and they claim works as well as purging. A fellow f-chatter told me hed tried it and was happy with the result so I thought Id give it a try and see what happens ..on a weld that I can grind the back of if Im not happy. Im also going to grab some fittings at the hardware store today so I can run a purge line off my argon tank so I have that option too.
