Lotus Europa Community
Lotus Europa Forums => Garage => Topic started by: Certified Lotus on Friday,March 31, 2017, 04:35:59 AM
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I'm starting a new thread on the subject of custom exhaust manifolds for the Europa Twin Cam engine. In my rebuild thread of 2358R the subject came up and I've started to research the different types available as my engine will be coming back from Quicksilver Racing soon.
For those of you that don't know me. I'm not a "keep it OEM" type of guy. I like taking a well designed sports car and enhancing it a bit for performance. In my mind, most car manufactures had to either conform to some silly law or use readily available parts to keep cost down (or both). The areas I focus on the Lotus cars I have owned are increased engine performance (HP & torque) and suspension (better coil over shocks).
How many different types of exhaust manifolds (headers) are available for the TC engine that will work in a TC Europa? Please post examples with manufacturer cost and a photo. Any personal experience would be greatly appreciated.
RD Enterprises sells a nice mild steel header that is great for a stock engine. It is fairly inexpensive and they have the entire exhaust system to bolt in. ($295 for the header and connecting pipe). Pipe diameter of primary pipes 1-3/8"; outlet pipe is standard 1-3/4". Headers include elbow pipe for attachment to muffler.
TTR (Tony Thompson Racing) in the U.K. Has a big bore header available that is designed for the performance of a 26R engine. ($562 plus shipping to US) I have this on my Elan and it is well built. I wonder if I can use this and custom make the balance of the exhaust pipe?
Kampena Motorsports used to carry a custom manifold for Elan's and Europa's but the builder stopped making them. Too bad, they looked well designed ($850 for the headers).
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As I said in the earlier thread, I have Ray's system on my TC. This has the advantage of my being able to keep the luggage box without change. This is because it turns through 90 degree and passes under the engine to the intake side where there's more room. No gear change, clutch cable, speedo cable etc. It looks like you might be able to cut the third one you show, and turn it around. I can't really tell, but it looks like it might be more challenging with the others.
I have seen systems where people have moved the battery and anything else that got in the way, and installed high-level exhausts that come out above the engine mounts and go rearwards from there, but they don't have the luggage box.
It'll be interesting to see what people come up with!
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There was a tubular header from Lotus as an option - it's shown in the parts manual. I wonder if any have survived?
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Hi,
As you know already, this topic is of interest to me as well and I'm currently awaiting the arrival of several bends and straight lengths of stainless with an aim of gluing one together.
I'm like Roger in that keeping the luggage tray is paramount so mine will follow the path of the original, ie down between the engine mount, gearchange and clutch cable, underneath the engine and meet up with the exhaust in it's OEM position.
One thing that strikes me about the first image is how long the primaries are, from the angle of the shot it gives the impression of being almost a 4-1 system. The following 2 shots look similar to Elan systems so at the moment I can't envisage how they'd work on the car.
Dave Vizard quotes 2 systems in his "Tuning Twin Cam Fords" booklet, the first a 4-2-1 for tuning above standard and then a 4-1 system for what he calls radical cam timing.
a) 1.625" (41mm) primaries at 13" (330mm) long, secondaries in 1.75" (44.5mm) again 13" long followed by a 2" tailpipe at 28" long.
b) 1.375" (35mm) primaries at 29.5" (750) long then a 5" long collector feeding a 2" x 22" long tailpipe.
Whatever you end up with I can't see it being worse than the OEM cast iron manifold. I've got one set up at the moment and it looks more like something designed to fit rather than something to produce power. 1-4 are very mis-matched lengths for example. I'll take some photos and measurements tomorrow, if nothing else it shows where the start points are.
Brian
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Banks Europa has one listed on it's website (Full system - hand formed headers - with Repackable muffler for $721. Anyone have one of these that can show us photos?
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My JPS came with a Dave Bean header. It's a multi piece system held together with clamps. I don't remember if it was a 4-2-1 or a 4-1 system. I didn't do a trial fit before I got it ceramic coated and had to oval out a couple of the holes to make a decent fit over the studs other wise, a good fit.
There is also the custom route as my spare engine has.
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Banks Europa has one listed on it's website (Full system - hand formed headers - with Repackable muffler for $721. Anyone have one of these that can show us photos?
Richard at Banks tells me the systems don't fit.
I am sourcing a local manufacturer in Norfolk as I need at least 3 complete systems.
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Since I wanted to keep the luggage tray, I opted for Ray's mild steel system. After having JET coating applied, I installed a single flexible pipe w/wrap to Monza exhaust tip. No muffler... clean, loud and within budget!
Brother Vic has the Banks system on 3522R, which he got some years back...a few more $$$...but sounds great!
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The Banks system look like the one on my TC
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Some real works of art on this thread, lovely workmanship.
And in complete contrast, this is what we started with, or at least what the UK TC cars came with. 3 shots taken today of my old one and as you can see although it's a compact casting there isn't a great attempt to equalise the primary tube lengths. The manifold joints are matched to the exhaust ports but it goes a bit strange as the secondary joint comes into play with rectangular openings. Is this better ? No idea but it looks strange to me.
In other news, my DIY kit of parts arrived today. Unfortunately we have a fireplace to build which the project manager claims has priority..... never mind, it's just more thinking time !
Brian
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It's not bad really. Not equal length but the 1 & 4 are separate from 2 & 3. Nice double downpipes and it would perform quite nicely. It also has the benfit of being much quieter.
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As a mass production casting I'd agree, but I'm confused by the square ports. I get they're trying to maximise surface area within the available casting but I always thought that square holes don't have uniform gas flows, the corners create dead spots and lower flow rate. On this design it's going from round -> rectangular -> round (in the downpipes) which I don't understand.
Incidentally, as this is a thread on exhaust headers, some more trivia I've read recently which may be of interest to anyone else who's also trying to understand these things. In the book "four stroke performance tuning" the author overturns something I'd always thought essential, that of matching headers to port openings. Basically the claim is that matched bores lose power and that you should aim for a step into a larger bore (which slows the gas ?). He gives an example of a 1600cc engine which shows gains both mid range and top end by having larger header bores than exhaust ports. Apparently it's all about impeding backflow, page 19 on google books if anyone else is intrigued by the idea.
Brian
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Exhaust design is complicated. Tuning an exhaust with specific length primary pipes and total length can have a significant affect in a certain rpm range. However, it often results in negative effects in other rpm ranges. Back in the day with single cylinder motorcycles, this was referred to as "megaphone-itus". Basically the reflected pressure wave is now arriving at an inauspicious time and messing up the engine's gas flow. Fitting a step in not technically an improvement as it doesn't improve anything. It makes everything a wee bit worse. So you loose a bit of the flow improvement during the happy rpm period but you also do not loose as much power during the unhappy rpm periods. This results in less peak power but can give a broader, more-useable, power range. In the old days striking this balance was a matter of extensive experimentation -- imagine literally piles of trial exhaust systems. Nowadays computers can reduce significantly the amount of experimentation required.
How relevant is this to a tractable street-prepared engine? Not much really.
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Grumblebuns
Is the Bean header system you have equal length tubes? Hard for me to tell from the pictures.
It has been a while, but last time I checked Bean no longer sells their headers. They may still sell the stainless double S system, I believe a copy of the factory headers, also not equal length.
Ray’s headers are a great price, but judging from the pictures are not equal length.
For someone looking for a bargain Paeco offered me a set of headers for $180, similar to what Ray sells. But it has been a while so they no longer sell them.
It may just be, that to get equal length headers for a TC you will have to make them yourself. So far I have been unable to find equal length headers at a reasonable price.
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When I spoke to Richard before ordering just a stainless replacement downpipe on system, he said the cast one doesn't perform that badly, you could build a 150nap engine on it. At least that's what I remember, I could be wrong...
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Resurrecting this thread to add a home-made variant to the list. At some point I'll detail the build if only for my own records but the basics are as follows;
1. I wanted a tubular header for the car, similar to the one I have on the Elan because when I installed that one the car did feel different afterwards. As I also wanted to learn TIG welding and it's always good to have something you will use afterwards rather than a bin full of test welds.
2. Design parameters were unashamedly copied from other authors. I settled on primary/secondary tube lengths based on Dave Vizard's book and tried to keep as close as possible to that within the confines of the engine mounts/clutch cable/gear linkage.
3. The 4 primaries aren't identical lengths but pretty close (within 1") and the paired primaries (1-4, 2-3)are better matches. Overall primary/secondary tube lengths are within 1/2", so I'm ok with that.
4. At my level of welding skill (or lack of) I couldn't fabricate a Y piece as shown on t'interweb. I just couldn't get a decent weld in the sharp confines of the "Y" so made one up out of a 90deg bend and some patching which allowed me to weld the inside of the "Y" rather than the outside like everyone else does.
5. The welding started off very badly, a world of difference between doing flat plate and 38mm pipe walls. Lots of remedial work and grinding off excesses, but it got better the closer I got to the exhaust box. By the last section it was almost decent....
And that's about it. Basic pipe routing copied from examples shown here, nothing adventurous or ground breaking here.....
Brian
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Impressive endeavor Brian! I'm always in awe of anyone that takes an idea and moves it to completed product even without the necessary skills to do so. I learned to weld 40 years ago and did it for several years then stopped. I shudder to think that I could just pick it up again.
Nicely done!
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That looks pretty nice to me, Brian! I think you did yourself proud. Building headers seems like a very complex project and your first attempt looks very nice! Can you feel an improvement when you drive her?
I'll be watching for you to open Brian's Custom Headers! :)
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Brian, very impressive result especially this being your first time DIY attempt. How did you fabricate the header flanges and what did you use as a fixture jig during the welding process?
Joji Tokumoto
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Very impressive effort, Brian. The fit seems good. Looks like a nice pipe. Hats off to you, sir.
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Brian,
Looks great. Are you using a gas lens on your TIG torch? If not, I would recommend getting one (or a set if you are using different sized tungstens). With the gas lens you can have a longer stick-out that will help welding in tight spots (the insides of Y's etc).
Rod
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Last question first... yes Rod, I had a gas lens on the torch with the smallest ceramic that came in my gas-lens set. The problem isn't the tools, it's the guy using them; I'm just not steady enough and when I tried the arc kept wandering to the sides. My welding isn't great close up but that first Y attempt was a real shambles, hence my trying another way.
And it worked out really well. Take a 90deg mandrel bend, split in two halves and then set them the correct distance apart, cutting the angles to suit and using the outer walls for the gas flow. That left enough room for me to weld inside the bore of the pipes with a little bit of patchwork to close it all up. Heavy on welding time but better on gas-tightness for me !
Joji, the flanges were bought pre-cut so I didn't have to cut them from plate. They are 8mm 304 stainless with elongated holes for the studs which allows them to be used on several engines. (I cheated wherever possible ;) )
For a fixture jig, I happened to have a spare TC head lying around which I mounted on a portable workbench and used a sheet of cardboard to get the rough positions of the engine mount, which is the first clearance problem. I cut tubes and used gaffer tape to hold them together so I could transfer it to the real car for confirmation, back to the spare head for tack welds, back to the car for checking.... rinse, repeat. Now you know why it took me so long !
Jim, I don't know about improvements when driving, I was just glad when it fired up and didn't fill the engine bay with leaking exhaust fumes !
Quite honestly I doubt there will be any noticeable difference as it stands but I've decided to change the camshafts this year and I think it will come into it's own then. There's a hint from one book I read which claimed a mid range improvement by NOT matching the port/tube bores even on standard engines and that's what I've done here. By coincidence I found a page detailing the Trikbits custom headers for the Elan using almost the same dimensions for tube bores, which gave me a bit of confidence in the idea.
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But can you get the stud nuts to screw up tight using a normal socket?
I have had to buy allen headed 5/16" UNC S/S bolts so at least I can get them bolted up easily without making up strange tools or resorting to mole grips.
I have 3 complete systems being made in S/S ATM, plus one for across the pond.
I even bought extended brass nuts (like fitted to Minis back in the 60's. )
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But can you get the stud nuts to screw up tight using a normal socket?
Nope, the only way I could see that happening easily would be to bring the pipes out further at 90deg to the flanges so the nuts are all clear of the bends. I'm sure that's practical because there's quite a bit of room on the Europa installation.
However I haven't had to resort to anything fancy to assemble this set up. I used 1/4" drive sockets with extensions for most of them with a stubby 1/2" spanner on two nuts where the bend comes back across the stud. It looks awkward but it's gone together very easily. I used conventional brass nuts with stainless washers but that's a good idea about extended ones, they'd fit a treat for the ones hidden underneath the thermostat housing. I must check out Mini-Spares.
Finally I hope your welder isn't spending the time to make yours that I did on this one. If so, I can see a second mortgage or a car being sold to pay his bill !
Brian
Edit to add - a good shout on the extended brass nuts Alex, just bought 10 from Ebay. And I was expecting to struggle to find any !
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£850 + VAT per S/S complete system. Man in Norwich.
The extended brass nuts 5/16 UNF are available on eBay. So are the UNC S/S allen headed bolts.
Man with Lotus fibreglass molds in Snetterton Ind Est is repairing my boot box for £30. "Just put it in the mold and repair it"
Man near Lotus factory is spraying 3089R from Tawny Brown to Lagoon Blue.
Man near Lotus factory is upholstering batch 5 of 7.
Man in Loughborough still has my seat for a pattern for making ally ones.
Meanwhile 4688R is nearly ready for engine. Just the dashboard to go in with the spaghetti behind and a few minor things, then the interesting stuff starts. Trimming a bare shell is time consuming. Cutting the thick dense underfelt lost skin from middle finger from scissors. There must be an easier way of cutting it than a Stanley blade then scissors. It has new loom, rechromed bumpers, new rad, new fuel tanks, new rubber and all pipes, new dash, lights, locks, door handles, alternator, starter cylinder head, new vent discs, new rear discs, Minilites and 185 Yoko tyres, 40 DCOEs and chassis. Just about the only originals are the bottom engine, the gearbox, the repaired shell, repaired doors and window frame, the rear screen, and the suspension arms.
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Wow, loads of work going on there. I bet you've got as much going on as Richard, and it's supposed to be his day job ;)
4688R sounds like it's going to be a stunner, is this the "Keeper Car" ?
Circa £1k for a complete system looks very upsetting at first sight but with the benefit of the last month I can well understand it.
The costs for mine were roughly - 1st order, mandrel bends, straights, flanges - £130 (ish). 2nd order - £25 (due to re-design once I had the bits ::) ). That was enough tubing to make the system you've seen, basically the pipework to the rear box. Rear boxes were available from the same source, IIRC it was around £60 for the bare box which would need inlet/outlets welding on. Flat sheet for collectors, etc, £24 (304 kitchen splashback offcuts from Ebay) Say around £240-50 if you wanted a complete system in kit form.
I also used most of a gas bottle, cutting discs, welding wire, etc. Say another £100 for sundries to do the job, so it would have come in at £350 for a complete system. Ok, much cheaper than your bill but..... this has taken me the best part of 2 weeks to fabricate and although a professional will be much faster I could see a week's work. So very easy to run up £1k for a custom system. In fact I can't see how SJS sell tubular headers at £225(ish) a set unless it's ferritic SS and smaller bores.
All of which makes the headers supplied by the specialists seem very good value. I spent more on making mine than I would have done buying one from SJS. Fortunately that's something I realised before I started but this wasn't about saving cash, it was "because I want to"..... something the wife struggles with at times :)
"why not just buy one and bolt it on ? then you can do the fireplace.... "
Brian
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All of which makes the headers supplied by the specialists seem very good value. I spent more on making mine than I would have done buying one from SJS. Fortunately that's something I realised before I started but this wasn't about saving cash, it was "because I want to"..... something the wife struggles with at times :)
"why not just buy one and bolt it on ? then you can do the fireplace.... "
Brian
Brian, I know exactly where you are coming from. This is my thinking when I go forward with my brake projects. It's fun and I learn a lot during the process. Good job.
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Thanks to Alex (he brought one of his Europa's over to 1st Performance and Exhausts Ltd. in Norwich) for getting the pattern made for these custom Stainless Steel exhaust systems.
I now have one here in the US😎
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I am glad the box of bits arrived safely. What do you think about the quality? I thought it is very well made, the welding is very good, the clamps are excellent, and you can actually do the manifold nuts up.
I have used extended brass nuts which cover the whole stud thread, so rusting of the thread just shouldn't happen. I have even thought about drilling the nuts and lock wiring them in place. I will see if they work loose in time to see if this is necessary.
Alex in Norfolk.
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Alex, it is very well made and I was very pleased that it comes with all the clamps. I greatly appreciate that you let me be part of the "production run". 1st performance told me it was the first time they shipped an exhaust system to the US.
It will be months before it get's installed as I'm waiting for my engine to come back from Quicksilver Racing, but I will follow your lead and use the extended brass nuts.
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You might want to have Quicksilver dyno the motor with those headers.
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Lock wiring is not a bad idea but do several retorquing after heat cycles until the torque is stable before actually wiring them.
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Lock wiring is not a bad idea but do several retorquing after heat cycles until the torque is stable before actually wiring them.
Do they come loose then ? When I took the manifold off my car to make a new one it had been in place for, well, I can't remember how long but it must be 10 years or more. Is this lock wiring a racing thing ?
Brian
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A lot of it is a racing thing. A lot of it is a belts & suspenders thing and a lot of it is a coolness thing. I try to wire every bolt that doesn't have a lock nut on the other end but I admit that sometimes I just get lazy. I like doing it for all the reasons I listed but I find it especially useful as a way of KNOWING that a bolt is tight - and can't come loose. I'm so forgetful that that visual confirmation is a great comfort to me.
As for the brass exhaust nuts, they tend to lock themselves when they get hot since the coefficient of thermal expansion for brass is higher than steel (at least that's the explanation I heard many years ago but it seems I also remember in engineering class that the hole in a heated piece also grows). In any case, wiring tall exhaust nuts seems like a good (or at least a neat) thing to do though I've never seen it before. As for myself, I've been using jet nuts (metal lock nuts) for my exhaust. I have worried that the heat cycles might relax the steel but it doesn't seem to have.
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You have to go through several heat/cool/torque cycles until the gasket settles. After that vibration can cause them to loosen and the TC engine has been known to vibrate things loose and/or develop fatigue cracks.
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I'm resurrecting this thread on exhaust manifolds for Twin Cams for continuity purposes, rather than begin a new thread on the same topic.
I've got a '74 twin cam (4173R) that needs a complete exhaust system. Within a month of buying 4173R I purchased another twin cam that runs and will be my driving car while I work on 4173R. The running vehicle has an exhaust system that came from "Lotus Prepared By Claudius" lotuspbc.com. It is a nice exhaust system although the header has been welded twice. I've been in contact with lotuspbc and they haven't made any headers in quite awhile. They will make a production run of 10 but at a cost that seems excessive, though I haven't determined if their price is negotiable. They will also coat the header with ceramic for an additional cost. I have not determined if there are 8 other Europa owners looking for headers to fill the production order.
I'm looking for a deep throaty muscular header, if that makes any sense, that is already in production. This thread began the header discussion. It is a bit dated since the last post. Nothing in the way of providing performance header vendors, other than 1st Performance and Exhausts Ltd.
Hopefully there is recent information on vendors with performance headers especially with many Europa's currently under restoration.
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I am posting about headers here because I can use this website. There is a long discussion of headers on groups.io. I don't know how to attach files on that blog.
Anyway, I have used on my tcs both the RD Enterprises and what I think are the Dave Bean headers. I don't know for sure because my car came with headers made by RS Engineering in California. They look exactly like the headers in the photo Grumbebuns posted in this topic. I called Ken about these headers and apparently Dave Bean worked with RS Engineering on the header design, so I think they are the same as the Dave Bean headers offered today. Ken said they could make them but they were something like $2500 in S.S. Mine are just steel. Dave Bean also sells another header design for the Europa TC. It looks like a 4-1 design. I don't know the price, but I attached a photo of it which Ken sent me.
I attached a printout of the design and the analysis. There is a header calculator at the website shown on the pdf file. I am not sure the basis of this model but there are a number sites online which reference the same header design formulas. It is probably based on transient gas flow dynamics and empirical data.
Anyway, the Dave Bean design matches the prediction very closely for putting the peak torque around 5500 RPM. Also, the DB header primary length were matched within 1". The only disadvantage I see is that the DB headers are much more expensive than the RD ones. Another advantage of the DB header is that the 2-1 merge collector is horizontal to the ground so the ground clearance is about 1.5" more with these headers than the RD design.
The RD design has somewhat unequal length primary tubes, (approximately 3-6") and the merge collector is perpendicular to the ground, reducing ground clearance. Also, the secondary tube length is very short. The tube diameters are similar. The DB secondary pipe ID is slightly larger at 1.375 vs 1.35 for the RD header. The overall length "P" in the analysis is about 6" shorter than the DB design, so the peak torque will be at a higher RPM
I attached my chassis dyno run showing peak torque at 5000 RPM. I think chassis dynos skew the torque curve to lower rpm because the transmission losses are not constant with speed.
For reference, my car has sprint cams and 10.3:1 compression ratio.
From the dyno data comparing favorably with the header analysis program, it may be a good design tool.
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Thanks for that, Pfreen! I believe the header discussion started with a guy who lives not far from me. I'll send him a link to this in case he misses it.
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I bought headers from SJ Sportscars. They are stainless steel and with the exchange rate now in our favor they were not too expensive. Might be worth taking a look.
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I bought headers from SJ Sportscars. They are stainless steel and with the exchange rate now in our favor they were not too expensive. Might be worth taking a look.
Even without a favourable exchange rate I think they are good value, I paid more to make mine from tubing than it would have cost me to buy a ready made one from SJS. The only downside I can see is that from the photo on their website the primaries don't seem to match up well although that's a criticism that applies to the OEM cast iron manifold as well. Even so I don't know how they manage to make them at that price.
Brian
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Thanks for the info Pfreen.
I've been in contact with Ken at Bean. He provided some useful information about their headers and exhaust system.
I've got an email into Banks and will likely follow-up with a phone call to them and RD. To Brian's point, the SS headers from SJS are intriguing. Ironically, they will likely last longer than the car. LOL
Ultimately, the question is, who can I buy headers from other than Bean, Banks, RD Ent, and SJS?
I'm getting the impression those are the only 4 who currently provide headers. :headbanger:
Thanks
Regards,
Jack
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Paeco in Alabama sold them, but they appear to be out of business, or their website is at any rate. Their reviews are not very positive as well.
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I am very pleased with the headers and silencer (oxymoron as the exhaust system sounds very mean) I got from 1st Performance and Exhausts Ltd. in Norwich (Alex had them custom fabricated). It’s not cheap, but it’s also not expensive when you realize you get the whole system. I would do it all over again if I was building another car.
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I went back and looked and they are beautiful and look very well made! I can believe they weren't cheap but if you have the money and motivation these look great! I reposted the picture Certified posted of them.
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Thanks BDA. Here are 2 photos of it installed and a video of what it sounds like.
https://youtu.be/dlaZESDiYes
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Now that's a very nicely designed system fro the street. Well worth the price.
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Here is a good article of equal vs unequal length headers and 4:1 vs 4:2:1 merge collectors. It is written about a Subaru but the principles are the same.
https://www.comeanddriveit.com/engine/equal-vs-unequal-length-exhaust-manifolds
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Thanks for the info Glen.
I will contact them.
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'madness got me thinking about design theory for headers. I remember reading a book about it when I was racing and in engineering school. A brief look at the article he pointed to seemed like it might be geared for turbos or even Subaru flat engines. I say that because I remember that one of the design goals was to match the low pressure of the pulse from one runner to help scavenge the exhaust gasses in another runner. This is one reason why headers are designed for an rpm range and on a straight four, that would require equal length primary runners. V and flat motors are more complicated because the low pressure in one primary tube that is needed to help scavenge the exhaust gasses of another primary tube (or combustion chamber) could be on the other side of the motor which would require one or more primary runners on one side of the motor to connect to runners on the other side! Of course this is not only dependent on motor configuration (flat or V) but also the firing order which depends on the crank for an engine with a dizzy ignition. Before I get any further past my real understanding, I found this article that explains some of this (https://www.onallcylinders.com/2015/10/30/header-theory-part-1-looking-at-the-science-behind-exhaust-header-tuning/ and https://www.onallcylinders.com/2015/11/27/header-theory-part-2-tuning-header-collectors-for-optimum-performance/). These would probably interesting reading for someone more interested what goes into header design.
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Both articles agreed that it is best to get as close to equal length as possible. I have r.d. headers currently (actually pfreen's old headers) But now I am reconsidering getting one's that are equal length.
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Kelvedon (https://kelvedonlotus.co.uk/ )in England also sells headers. I don’t know anything about them. They cost £446. I have bought parts from them with no problems.
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If you are interested in this topic may I suggest you read the bibles:
Scientific Design of Exhaust and Intake Systems
Philip H Smith
Four-Stroke Performance Tuning
A Graham Bell
From recent yahoo/io posts:
4-1 systems are very effective over a relatively narrow range. They also have a strong “anti-tuned” frequency which causes “reversion”. This works well in a highly tuned engine where the cam is also tuned to a similar range — though it makes for a “peaky" engine.
4-2-1 systems do not give as large a hit at the tuned rpm but they provide a significantly broader effective rpm range and suffer much less from reversion.
Again, all from dim memory.
Right now I’m struggling with reversion (also known as megaphone-itus) on one of my bikes. I have a beautiful pipe with a 2° taper that works very, very well. Hardly any reversion and great power. Unfortunately, the exhaust volume is so low that it is noisy, very noisy. How does a 140+ db at full chat sound? Glorious but setting off car alarms is the norm not the exception. I also have a 4° tapered pipe with the same top end and much, much quieter due to the larger volume. But it has a simply massive hole a few thousand rpm below peak — like shut it off and park it massive.
All that is why I was very careful when I built my Europa’s exhaust. I use a Banks 4-1, yes, but I situated the muffler sideways for a longer main pipe and, so I can fit a very large, though still free-flow, muffler. Add a relatively unrestricted short super-trapp as an outlet, and my exhaust is both free-flowing and quiet. I also deliberately did not match the tuned frequencies of the header and the cam. This broadens the power band significantly. I have a really fat mid-range (mostly cam) with a nice top rpm hit at 6000 (mostly pipe). Ultimate hp is modest compared to theoretical but it makes for a great street engine.
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If you are interested in engine tuning I also recommend Cycle World’s Kevin Cameron. His columns are collected in "Top Dead Center" vol 1 and 2. Even more fascinating is his book “Classic Motorcycle Race Engines”. It covers the history of engine design at the same time as you examine in detail race engines from the 20s on up. Every wonder why engines originally had such long strokes? Why some engines have twin spark plugs? What are the advantages and disadvantages of forged and cast pistons? It’s all there in a detailed but easy to read style.
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I have R&D headers currently (actually pfreen's old headers) But now I am reconsidering getting one's that are equal length.
For what it's worth, I think that's "R.D.", as in "Raymond D." Psulkowski, proprietor of RD Enterprises, rather than R&D.
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I stand corrected. I should know better because I certainly have accumulated enough r.d. enterprises, ltd invoices over the last few years (plus phone calls). Oh well! :)
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Hey guys,
Well my cast iron manifold has a small crack in it and I think its time to get a new header system. I like the stainless steel that SJ has but shipping it over here compared to Rays Mild Steel header system has me thinking, is it really worth it? Any of you guys have a used one laying around?
I will purchase one of the two above soon, just not sure which one but I am leaning towards Rays because of the shipping costs.
Thanks,
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Hey Kid!
First, I would check with Dave Bean to see if they have stainless headers.
As for the actual headers, my experiences may or may not directly translate to you but they may be helpful.
You should know that one stainless steel is not necessarily as stainless as another. Unfortunately, I don't know which alloy to point you to but it might be worth asking about that when you shop around.
An option you might want to be aware of is ceramic coating. It can be applied to any header and provides cooler engine compartment temperatures, corrosion resistance, and a nice look. Here is one place that does it: https://www.jet-hot.com. There are also rattle can and brush on ceramic coatings. I have no first hand knowledge about either but I don't think I would bother with a rattle can.
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Gave Dave Bean a call and they do not have SS headers anymore, just the mild steel.
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Bummer!
That wouldn't wouldn't let shipping from England dissuade you. It's probably quicker and more economical than you expect.
As an alternate supplier, I just checked with Lotus Supplies and they have a nice setup including muffler that looks pretty reasonable (https://www.lotus-supplies.com/part-category/exhaust/twincam/page/2/). Lotus Supplies is probably best contacted by phone. I have no specific knowledge about either of these headers but looking at the pictures, it would not surprise me to find out that SJ gets theirs from Lotus Supplies. I know both companies to be reputable and I would not hesitate dealing with either of them but it may turn out that because of the Wuhan flu, you may not have a choice of supplier.
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I found the Phillip Smith book very old fashioned whereas A Graham Bell updates his Four-Stroke Performance Tuning regularly, V4 has been out for 10 years now & has plenty of BTCC engine info of the early 90s whereby the engine control was 8500rpm to limit hp to around 300bhp from 2ltrs /122 CI otherwise it could have been 330/350 bhp or more.
Bell has interesting theories on exhaust primary unequal lengths & anti-reversion mismatches, the latter I have dyno tested on one & used on 50 + engines, although I knew about them from Vizard's A series engines & the guy who used to port our heads was an ex Cosworth cyl head guy, from DFVs through Sierra's & J series Opel's
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I do a lot of 2 stroke work. Mild steel is easier to fabricate and less likely to crack with vibration. It will corrode but you can ceramic coat it to help stop that. Stainless looks super cool polished but is more likely to crack with vibration. I dob'y mind SS for pipes but for headers with a tight curves and a lot of welds, I prefer ceramic coated mild steel. YMMV.
In any header, I look first at the flange that mounts to the head. It should be thick, very thick. Next I check that it lines up with the mounting holes properly and I match the ports. I then send it out and get the flange surface ground. Works like a charm, no leaks.
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Thanks guys - Yes I've been to Banks Europa's website and I have seen the SS one he has.
If I go Mild Steel, I will definitely get them ceramic coated, I found a shop near my house that can do it for me. Not sure about price but can't be too bad.
I have a feeling I'll go with Rays Mild steel and get them coated, it seems like I always go to Ray. He has helped me out a lot over the years. Just wanted some other opinions, thoughts, comments or suggestions.
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My headers are ceramic coated. But I haven't been able to get them not to leak. Can the ceramic coating be milled flat? Or do I need a thicker gasket?
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Try filing it flat in a vice, to try and save the coating on the rest of the surface? If that doesn't work, you may need a thicker flange if a double gasket won't work.
I have the big bore Dave Bean headers, they are quite nice, excellent workmanship. I talked to Ken a year ago about them, and he had priced new sets but the cost was over 1k, so he didn't think he could sell them on. I had the SS ceramic coated too, since the radiation off the shiney SS was too much (melted a throttle cable, throttle stuck, crikey!! that was frightening), to reduce under hood temps. Also, they hit the stock shift linkage, and I didn't want to dent the new headers to clear, so moved the pivot point. That changed the H pattern to a angular pattern....not good. Eventually went to a modified trans and side shifter.
Jerry Rude
4005R
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Thanks for all the info, I now know I have nice a non-standard 4 into 2 in 1 exhaust.