Piglet Posted June 6, 2022 Report Share Posted June 6, 2022 All my previous Spitfires had chrome K&N filters on but Lora doesn't, She has that enclosed box thing with paper filters inside. I'd like to fit K&Ns instead but I'm wondering what all the tubing that goes around the standard box actually does and should it be removed or left in situ? Alex Link to comment Share on other sites More sharing options...
cliff.b Posted June 6, 2022 Report Share Posted June 6, 2022 11 minutes ago, Piglet said: All my previous Spitfires had chrome K&N filters on but Lora doesn't, She has that enclosed box thing with paper filters inside. I'd like to fit K&Ns instead but I'm wondering what all the tubing that goes around the standard box actually does and should it be removed or left in situ? Alex Do you mean the two "corrugated" pipes that go to the front of the car or some other pipework 🤔 Link to comment Share on other sites More sharing options...
johny Posted June 6, 2022 Report Share Posted June 6, 2022 Or the fuel pipe that goes round the front of the airbox? Link to comment Share on other sites More sharing options...
Piglet Posted June 6, 2022 Author Report Share Posted June 6, 2022 Good questions! I'll get a pic tomorrow, it might explain things a little better. Alex Link to comment Share on other sites More sharing options...
DanMi Posted June 6, 2022 Report Share Posted June 6, 2022 the pipework allows the carbs to suck in denser cold air from in front of the radiator, rather than the thinner hot air from near the exhaust manifold Link to comment Share on other sites More sharing options...
Piglet Posted June 6, 2022 Author Report Share Posted June 6, 2022 And that's a very good thing too. Cold air is less dense. I keep on wracking my brain about the pipework but like I said I'll get a pic tomorrow. Alex Link to comment Share on other sites More sharing options...
PeteH Posted June 7, 2022 Report Share Posted June 7, 2022 It`s the reason you see intercoolers on Turbocharged Engines, Increased Air density = More oxygen available for the combustion process (simplified). When air is compressed, even "ram" air, it`s temp; increases, cooling increases density. Pete Link to comment Share on other sites More sharing options...
NonMember Posted June 7, 2022 Report Share Posted June 7, 2022 Yep, K&Ns are all very well for bling but they're not good for performance. Better to leave the original air box and filters on. Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 7, 2022 Report Share Posted June 7, 2022 agree , a must if have you want a headache of hot running problems and continually reading about and playing with needles pete Link to comment Share on other sites More sharing options...
Gully Posted June 7, 2022 Report Share Posted June 7, 2022 I caught a relatively recent episode of Wheelers Dealers last night on Quest, where Ant was removing the $400 aftermarket air filter arrangement from a Porsche 996 and replacing it with a 2nd hand OEM part to move back to cold air intake as opposed to engine bay temperature. He estimated the aftermarket kit was costing 15% in power terms. Gully 1 Link to comment Share on other sites More sharing options...
Gary Flinn Posted June 7, 2022 Report Share Posted June 7, 2022 Not sure if you can fit the K&N's inside the original Air filter box? But surely if you can, this would be a slight improvement so long as you keep the air feed pipes on to feed cold Air into the filters I can remember fitting HS6 Doly Sprint carbs and K&N's to my first Vitesse, all it did was make it drink more fuel😞 Gary Link to comment Share on other sites More sharing options...
johny Posted June 7, 2022 Report Share Posted June 7, 2022 I still think we're talking about the fuel pipe that goes round the front of the airbox and is probably even more important to keep than the air pipes🤔 Link to comment Share on other sites More sharing options...
Adrian Cooper Posted June 7, 2022 Report Share Posted June 7, 2022 But isn't Lora a MK3 Spitfire? I didn't think that the cold air pipes came in until the MK4s. I also have a feeling that the MK3 does not have the breather pipe from the rocker cover to the air box either. So Johny's idea that it is the fuel pipes are the ones in question seems right to me. If so, I would see if the two 'P' clips from the air filter box will fit on the K&N filter mounting bolts and continue to support the fuel pipe that way. Adrian Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 7, 2022 Report Share Posted June 7, 2022 think we all need a photo loaded to see just what is fitted Pete Link to comment Share on other sites More sharing options...
Mjit Posted June 7, 2022 Report Share Posted June 7, 2022 1 hour ago, Gary Flinn said: Not sure if you can fit the K&N's inside the original Air filter box? On a Spitfire MkIV/1500 - not easilly. Last time I looked there wasn't either a single oval or pair of round filters in their range that were both shallow enough and small enough to fit inside the Triumph airbox. You can do it but it means banding the airbox out to a suitible filter depth - and life's too short for the extra little bit of performance you get. 1 Link to comment Share on other sites More sharing options...
Piglet Posted June 7, 2022 Author Report Share Posted June 7, 2022 So the general consensus is keep the airbox! Here's a couple of pics. I'm pretty sure Triumph didn't colour code parts! Is the airbox meant to be silver? Alex Link to comment Share on other sites More sharing options...
Josef Posted June 7, 2022 Report Share Posted June 7, 2022 Originally the airbox would’ve been black on your car, very late Mk3s had silver. Link to comment Share on other sites More sharing options...
Josef Posted June 7, 2022 Report Share Posted June 7, 2022 The fuel line running over the rocker cover looks like it’ll make removing the rocker cover a bit awkward! The standard run is between the rocker box and thermostat housing. Link to comment Share on other sites More sharing options...
Anglefire Posted June 7, 2022 Report Share Posted June 7, 2022 24 minutes ago, Piglet said: So the general consensus is keep the airbox! Here's a couple of pics. I'm pretty sure Triumph didn't colour code parts! Is the airbox meant to be silver? Alex This is surely no better than K&N's (Worse?) given the air is coming in through a couple of slots from the engine bay and not through the corrugated pipes from in front of the radiator. I still have to put some temperature loggers in mine to see what the real world effect is - I suspect when moving at a reasonable speed the temperature will be close to ambient. Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 7, 2022 Report Share Posted June 7, 2022 there are no cold air pipes on this set up what you see is what you get two rectangular holes facing upwards hence the mark of 'Top' Pete Link to comment Share on other sites More sharing options...
Piglet Posted June 7, 2022 Author Report Share Posted June 7, 2022 So...with no cold air pipes running K&N's is a possibility but only if I want to re-jet. I think I'll leave it alone...apart from painting it black! I'm now wondering if all my past Spitfires were low on power because of the filter swap. P'raps this is why Lora seems to have a lot of poke! Alex Link to comment Share on other sites More sharing options...
PeteH Posted June 7, 2022 Report Share Posted June 7, 2022 A Mate of mine, Sadly deceased, Used to opine there was a lot of "snake oil" involved in the "performance tuning" aftermarket. He tuned many an Escourt for rallying, quite successfully, mostly by making sure the power curve was "blueprinted" in the most efficent manner. Pete Link to comment Share on other sites More sharing options...
Peter Truman Posted June 7, 2022 Report Share Posted June 7, 2022 the small size of the two flexible inlet pipes from the front of the car to the air filter box always seemed Mickey Mouse to me such that in reality there wasn't any ram effect cold air yes. Modern cars with the air inlet pipework are significantly bigger. I always remember how well my car ran on a dark cold foggy night driving across the York Moors home in the mid 60's. 1 Link to comment Share on other sites More sharing options...
Anglefire Posted June 8, 2022 Report Share Posted June 8, 2022 I had a Vauxhall nova 1.3SR which had had a sport manifold fitted and No longer the exhaust air heater system. Occasionally it would stall even after a30 mile run up the motorway when coming to a junction because the mixture was so far out due to the cold damp air. similar thing with my vw beetle that had a exhaust bypass to the carb - that always choked up so didn’t work. Going up hill sometimes would cause it to cutout on full power (all 34bhp) as the carb froze. Link to comment Share on other sites More sharing options...
DanMi Posted June 8, 2022 Report Share Posted June 8, 2022 All the pipes that you have are nothing to do with air flow so would not be affected by a filter swap. The metal pipe is fuel, so essential. The rubber pipe with a T piece to the carbs is the crankcase breather, though that is not the mk3 setup, probably mk4 manifolds and carbs. Link to comment Share on other sites More sharing options...
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