micmak Posted March 25 Report Share Posted March 25 I have seen many photos of 1960s Triumph engines. They are all similar, for the most part, but there is one thing that struck me. It concerns the air filter. Some cars have flexible hose-type tubes from the filter box to the front grill area. My car doesn’t have this. Should my car, a 1968 MK1 Vitesse, have such things? Are they missing from my car, or is my car supposed to have nothing attached to the air filter box? Link to comment Share on other sites More sharing options...
johny Posted March 25 Report Share Posted March 25 Yes you should have two hoses that attach to the side of the rad and draw in cooler air. The clamp shown below goes in that hole you can see in your photo in the side of the rad... Link to comment Share on other sites More sharing options...
Gary Flinn Posted March 25 Report Share Posted March 25 Originally the Vitesse 6 and Early 2 Litre Vitesse's didn't have the flexible hoses fitted, the Mk2's did though. It is certainly a good idea to fit them though and get cold air into the Carbs/Engine. Gary 1 Link to comment Share on other sites More sharing options...
dougbgt6 Posted March 25 Report Share Posted March 25 A lot of people fit the pancake filters, very pretty, but not so good, you need cold air from the grill, not hot air from the engine bay. Don't be tempted to the dark side! Doug Link to comment Share on other sites More sharing options...
Chris A Posted March 25 Report Share Posted March 25 1 hour ago, Gary Flinn said: It is certainly a good idea to fit them though and get cold air into the Carbs/Engine. I agree. Interestingly enough the 13/60 just has the metal tube on the filter housing that goes part way in the engine bay not to the side of the rad. Triumph cost cutting ? Link to comment Share on other sites More sharing options...
Colin Lindsay Posted March 25 Report Share Posted March 25 1 hour ago, Chris A said: I agree. Interestingly enough the 13/60 just has the metal tube on the filter housing that goes part way in the engine bay not to the side of the rad. Triumph cost cutting ? I think many of us go the pancake filter route at first, thinking it to be a 'modern' and more efficient upgrade, then change back, and certainly the pancake filter was one of the first things I removed from my 13/60. Link to comment Share on other sites More sharing options...
68vitesse Posted March 25 Report Share Posted March 25 Not fitted to Mk1 2L as said, but when I made a stainless-steel air box I also fitted stainless hoses. Wether it made any difference??. Regards Paul. 2 Link to comment Share on other sites More sharing options...
Colin Lindsay Posted March 25 Report Share Posted March 25 11 minutes ago, 68vitesse said: Wether it made any difference??. Regards Paul. Who cares?? Looks great. You'd forgive any detrimental performance just for the fun of polishing it. 1 Link to comment Share on other sites More sharing options...
johny Posted March 25 Report Share Posted March 25 11 minutes ago, 68vitesse said: Not fitted to Mk1 2L as said, Wow didnt know that, am I right about the hole in the side of the rad for the fixing? How strange it was prepared for the hose clamp and then they werent used! Think they help at idle in traffic when under bonnet temperatures can rise but not so much when moving... Link to comment Share on other sites More sharing options...
micmak Posted March 25 Author Report Share Posted March 25 Well Guys, I have to say I felt a bit dumb this morning asking what I felt was a bit of a stupid question. But once again, I realize that every day is a learning day on TSSC's forum. Now, I am glad I asked and I might put tubes on my filter, or maybe not. I’ll see. I would imagine that if you don’t have them, you might have problems with the carbs overheating? I’d imagine it is better to have them. Surely drawing in cooler air is better. Thanks Everyone for your comments. …..Mick….. Link to comment Share on other sites More sharing options...
johny Posted March 25 Report Share Posted March 25 Looks like theres quite a hefty radiator fan squeezed in there Mick so that will help to keep the air moving under the bonnet when stationary👍 Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 25 Report Share Posted March 25 this old nutshell keeps popping up its simple cold air has more molecules of oxygen per bucket full than hot air so you get more bang from cold air than hot air why 1600/mk1 dont show any collecting tubes is a mystery we will never get the answer but but far better with than without !!! we made some nice smooth tubes from 50mm waste pipe 2 Link to comment Share on other sites More sharing options...
Colin Lindsay Posted March 25 Report Share Posted March 25 2 hours ago, micmak said: Well Guys, I have to say I felt a bit dumb this morning asking what I felt was a bit of a stupid question. …..Mick….. Not dumb by any means. You don't ask, you don't learn. I'm doing EXACTLY the same thing on the BMW forums at present - what does this do, how do you remove this bit, why doesn't my car have this bit and so on. I must admit to having received a reply or two that did make me feel about two inches high, but that's their fault for having that kind of superior mentality towards newbies, not mine for asking. 1 Link to comment Share on other sites More sharing options...
Chris A Posted March 25 Report Share Posted March 25 19 minutes ago, Colin Lindsay said: Not dumb by any means Exactly, no such thing as a dumb/stupid question, but there are dumb/stupid answers 😉 Sometimes what might at first seem to be a stupid answer can even be the right one. Link to comment Share on other sites More sharing options...
Ian Foster Posted March 26 Report Share Posted March 26 Late to the party on this one, but there was a similar thread in late 2022. My contribution at the time:- I think Triumph struggled with their twin carb airbox design, as there are many iterations from the early cars to later Spitfire and Dolomite boxes. The late saloon box has an enlarged box with a centre bottom feed. My GT6 Mk2 already had 175 CD2s on it when I bought it in 1977, but with an empty original airbox. Clearly a case of someone just slapping bigger carbs on. In my ignorant youth I put on a pair of wire gauze pancakes, which probably didn't filter or flow well, but made a lot of sucky noise. I subsequently bought a pair of K&Ns which I still have to this day which actually work well giving decent power and economy, but I am troubled by the fact that they are probably drawing hot air when the car is not moving. The early GT6 box had a pair of open tubes in the front and by the time they got to the MK3, Triumph had added the feed pipes. This arrangement seems to favour the front carb and there is a rectangular hole in the bottom of the box under the rear carb which is perhaps intended to compensate for this (or to let water out). The later Spitfire and Dolomite boxes have indentations in the cover (and presumably unequal length tubes internally) to distribute more air to the rear carb. There isn't space on my GT6 to do this. The TR(250) boxes seem to have various slots on the sides of the box, perhaps to address this issue, but surely this then also allows in hot air in when stationary. I have made a mock up of a new airbox to enclose my K&N filter elements, which flares out forward of the front filter (making use of the shape of the wheelarch) in order to accept a larger diameter single air duct into the radiator cowl. I have yet to commit the design to metal/glass fibre/carbon fibre, but it might just happen this winter. Ian Link to comment Share on other sites More sharing options...
JohnD Posted March 26 Report Share Posted March 26 (edited) It's a further mystery why Triumph provided TWO air inlets to the small chassis cars' air boxes. It's a well known factor and must have been to their designers, that the resistance to flow along a tube varies as the fourth power of the radius. That's RxRxRxR. Halve the radius and the resistance rises SIXTEEN times! (2 to the power of 4, 2^4) Instead of the two, a single intake duct with double the radius would have sixteen times more flow under the same conditions! Then, they seem to have designed the smallest possible airbox, that fitted tightly around a reasonably sized air filter. Another well known principle is Bernouille's. Air pressure falls as its velocity rises - that's why an aircraft's wing gets lift. Air flowing though a small box will have a lower pressure than in a large box, where it will slow down and raise its dynamic pressure. So as large an airbox as possible is desirable. Triumph, possibly persuaded by Lucas, must have learnt the lesson when they fitted Pi to their cars. A large airbox around the air filter and a three inch duct to the plenum tube, which is only three inches in diameter. So on my Pi-powered Vitesse I built a six-inch plenum/airbox, and mounted the air filter directly to the front of that. Given the cramped engine bay on the Vitesse, this puts the filter in the cold airflow alongside the radiator, and enlarges the plenum by four times! See below, OE plenum fitted, six incher ready to go. John PS The junction between filter and plenum is still three inches across, but that's an 'orifice' where the Bernouille rules don't apply, because of turbulence. Edited March 26 by JohnD Link to comment Share on other sites More sharing options...
Graham C Posted March 26 Report Share Posted March 26 I saw Peter L's reference to smooth pipes and John's reference to turbulence, this made me think. The original pipes were corrugated and must have formed some turbulence in the air flow,so I would think cause the air to slow, reduce volume per time, while smooth pipe would allow a quicker flow and larger volume per time. Any thoughts people on this or am I just over complicating the matter considering the short length of pipe? I do believe I read somewhere that turbulent air is better for carbs, which would suggest corrugated pipes were better. Over thinking Graham. Link to comment Share on other sites More sharing options...
Mjit Posted March 26 Report Share Posted March 26 29 minutes ago, JohnD said: It's a further mystery why Triumph provided TWO air inlets to the small chassis cars' air boxes. It's a well known factor and must have been to their designers, that the resistance to flow along a tube varies as the fourth power of the radius. That's RxRxRxR. Halve the radius and the resistance rises SIXTEEN times! (2 to the power of 4, 2^4) Instead of the two, a single intake duct with double the radius would have sixteen times more flow under the same conditions! While your math is (I'm assuming) correct you (a skint Triumph) can easilly weld two ~1" sections of cheap, straight pipe into the end of a ~1.5" deep airbox but for a single piece of 2" pipe you either need a straight pipe and 2.5" deep airbox, which could fowl the inner wheel arch or a flaired pipe and 1.5" deep airbox, which is an additional manufacturing process so additional cost. Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 26 Report Share Posted March 26 the Bum has no pipes but does cause a lot of turbulence Ha many use aquatic pipes on the air box as they are cheap and can be corrugated on the outside but smooth on the inside had to use this on my 2000 as waste pipes dont align with any cold intake easy. were Doomed ha !!! Pete Link to comment Share on other sites More sharing options...
johny Posted March 26 Report Share Posted March 26 28 minutes ago, Graham C said: I saw Peter L's reference to smooth pipes and John's reference to turbulence, this made me think. The original pipes were corrugated and must have formed some turbulence in the air flow,so I would think cause the air to slow, reduce volume per time, while smooth pipe would allow a quicker flow and larger volume per time. Any thoughts people on this or am I just over complicating the matter considering the short length of pipe? I do believe I read somewhere that turbulent air is better for carbs, which would suggest corrugated pipes were better. Over thinking Graham. Think its smooth air into the carb and then some turbulance in the manifold/head to promote the best fuel and air mixing... Also of course the airbox design has more effect the higher the flow rates so for my pootling I dont think its causing a major problem😁 Link to comment Share on other sites More sharing options...
Colin Lindsay Posted March 26 Report Share Posted March 26 38 minutes ago, Pete Lewis said: the Bum has no pipes but does cause a lot of turbulence Ha many use aquatic pipes on the air box as they are cheap and can be corrugated on the outside but smooth on the inside had to use this on my 2000 as waste pipes dont align with any cold intake easy. were Doomed ha !!! Pete That's exhaust rather than inlet, although you could use an attachment like the SNIP tailpipe (on cars!!) to extract gases more quickly. One other point as a totally non-Engineer / Technician - I understand the arguments for single and multiple pipes, and corrugated vs smooth, but does it really make much difference in a small road-going tootle of a car? Link to comment Share on other sites More sharing options...
JohnD Posted March 26 Report Share Posted March 26 (edited) Yes to Graham. A corrugated hose makes the functional diameter for laminar flow about a tenth smaller, less on a larger tube, more for high flows. What's a high flow - a Triumph engine! A 1500 at 4K pumps 3000 litres of air a minute! Imagine that through a pair of one inch tubes! That's over 60mph, just in the tubes!! Mjit, yes. Triumph penny pinching could easily have been the reason. The production cost of a deeper box and wider tubes would be in pennies per car. But dear man, you're in London! It's "maths"! Physics really, aerodynamics, but maths. Johnny, Less turbulence, more "swirl"! Modern engines with very lean combustion use a stratified charge, richer at the ignition point, achieved by some very clever swirl and "tumble" in the induction, where turbulence which is essentially random wouldn't do. JOhn Edited March 26 by JohnD Link to comment Share on other sites More sharing options...
johny Posted March 26 Report Share Posted March 26 5 minutes ago, JohnD said: Johnny, Less turbulence, more "swirl"! Modern engines with very lean combustion use a stratified charge, richer at the ignition point, achieved by some very clever swirl and "tumble" in the induction, where turbulence which is essentially random wouldn't do. JOhn Yes dont they recommend not polishing inlet manifolds too much but leave a bit of surface roughness to give some turbulance to aid mixing👍 Link to comment Share on other sites More sharing options...
JohnD Posted March 26 Report Share Posted March 26 Yes they do but not to induce turbulence. A matt surface will tend to discourage 'pooling' of excess fuel, and promte consistent mixtures. John Link to comment Share on other sites More sharing options...
johny Posted March 26 Report Share Posted March 26 I know its a very involved subject and this is Wikipedia's take on it: 'Turbulence in the intake helps to break up fuel droplets, improving the degree of atomization. Better atomization allows for a more complete burn of all the fuel and helps reduce engine knock by enlarging the flame front. To achieve this turbulence it is a common practice to leave the surfaces of the intake and intake ports in the cylinder head rough and unpolished' Link to comment Share on other sites More sharing options...
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