alarmman49 Posted August 27, 2015 Report Share Posted August 27, 2015 Hi everybody, I'm coming to the end of a 2 year "renovation, tidy up, sort out, put right" of my previously abused and very unhappy 1981 1500 Spitfire. The car is now a really usable classic with various sensible upgrades ( better brakes, etc etc.) and I am really happy with it. Question 1 : should I re-instate the missing engine valances ?? I have read various articles suggesting leaving them off, others say they improve engine cooling as well as the obvious keeping the engine a little cleaner from muck thrown up. I do have the radiator ones fitted. Question 2: I am running with K & N filters and have read that all engines prefer "cold air" supply through the carbs hence the hoses on the original Triumph air filter, should I run some form of hose to supply the K & N's with cooler air ??I am trying to ensure the carbs run at their optimum re performance and fuel economy. Any comments would be welcome, thanks, Tony. Link to comment Share on other sites More sharing options...
Mjit Posted August 27, 2015 Report Share Posted August 27, 2015 Question 1: Not sure if it's better or worse but I never got around to reinstalling them on my Spit after it's (body) restoration and can't say I've seen much different in road dirt getting on the engine/temperatures vs. driving with them on before restoration. Question 2: Cold air's more dense so has more O2 per-litre than warm air. More O2 means more bang, means more power. In reality there's not much difference on the move but it won't be so keen on sitting in traffic queues/pulling for the first 30s after pulling away from being sat in traffic - and even then heat soak in to the carbs/fuel vaporization will be part of that and an issue with/without a cold air feed. If you want every last hp, then a cold air feed is the way to go but is it worth the time, effort and money... 1 Link to comment Share on other sites More sharing options...
PeterH Posted August 27, 2015 Report Share Posted August 27, 2015 I thought they were supposed to make engine cooling worse. I've got them fitted on my Mk3 and it does run quite hot, particularly in traffic (std mech fan). I've put this down to the hot air not being able to exit the engine bay. Don't forget early GT6s had louvres in the front wings to help with air flow. Link to comment Share on other sites More sharing options...
Clive Posted August 27, 2015 Report Share Posted August 27, 2015 I heard they improve cooling, channelling the airflow correctly or such like. Not a lot of heat comes out the sides of a spitfire bonnet, and the GT6 louvres are not very efficient. Otherwise they would have kept them for the later cars (maybe) Link to comment Share on other sites More sharing options...
dougbgt6 Posted August 27, 2015 Report Share Posted August 27, 2015 I'm a great believer in keeping it the way Triumph designed it with the exception of reasonable upgrades like electronic ignition, braking improvements, inertia reel, comfy seats etc. They put in engine valences for a reason, they route air flow over the gearbox and under the car. They also keep road dirt off the engine. What's not to like? similarly the air filters, if I bought a car with K & Ns, they would be the first thing to go! Followed by the electric fan and any suspension lowering gubbins! 1 Link to comment Share on other sites More sharing options...
Colin Lindsay Posted August 28, 2015 Report Share Posted August 28, 2015 If I bought a car with K & Ns, they would be the first thing to go! Followed by the electric fan and any suspension lowering gubbins! I always reckoned that with things as tight as they were in pricing and costs, if the valences weren’t required, they’d have been removed by Triumph. Consequently there had to be a reason for their continuing fitment - probably keeping dirt off the engine and improving airflow. As for K&Ns… everyone upgrades when they first buy, then after a few years they ditch them and go back to standard… my first Spitty got oil cooler and thermostat, electric fan, uprated springs, K&N filters, additional dials.. then they all came out again when I realised they were for show - because everyone else was doing it - and didn’t make one hoot of difference to the car’s performance or longevity. Link to comment Share on other sites More sharing options...
PeterH Posted August 28, 2015 Report Share Posted August 28, 2015 I can only comment on the Mk3, but the parts book lists the valances as: 'Fitted to all vehicles up to Comm. No. FD22863 L.H.S. and FD16350 R.H.S. Fitted to Special Order only under kit no 569563 from Comm. No. FD22864 and FD16351.' These were the two different ones i.e. a left and a right. Then 1 under a different part number for Engine Bay R.H. only for USA from FDU75001 Link to comment Share on other sites More sharing options...
Steve C Posted August 28, 2015 Report Share Posted August 28, 2015 You are so right Colin - experience teaches that Triumph actually knew what they were doing (even if it was down to a price..) and that every mod brings in its wake some knock-on effect or problem you had not bargained for, which then needs another mod. Only in the latter days of the marque were they guilty of some really poor ideas - Waxstat jets, cardboard washers in diffs, dodgy spit downpipe gaskets all come to mind. Mind you, the lack of fuses on most of our cars does count as a shocking bit of penny pinching, even if the threat of instant immolation does keep us alert! Steve-C Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 28, 2015 Report Share Posted August 28, 2015 wax stats and temp compensators were a requirement to aid emmissions in the 70/80s , same a s thermac air filter controls it was needs must rather than triumph wanted, applied to most manufactures of the day. there were lots of bright idea's used to lower Co and HC content , I ran an emission dept with gas bags , gas fridges , volume metering and gas analysers in the 70s and 80s, for pertol engined trucks and diesel smoke and we were all caught up with tamper proofing , and wild idea's to get the levels down, the spin off was the cost of fuel took over and to get better economy the ideas grew and levels dropped to the fresh air out the exhaust like todays vehicles and mpg unheard of when our cars were tops. the lack of fused circuits was also the norm for the designs of the day , not skimped just normal for the trade Pete Link to comment Share on other sites More sharing options...
Steve C Posted August 28, 2015 Report Share Posted August 28, 2015 Lack of fuses normal? I hate to differ, but au contraire guru Pete! In the sixties, SAAB, VW and Volvo all had them, but then they were all properly engineered...which is why I am now on my 7th Volvo. Steve C Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 28, 2015 Report Share Posted August 28, 2015 No guru , just a wide range of truck manufacturing experience over 40 yrs luckily theres more triumphs about with 2 fuses than saab 96 of the era ha !!! pete Link to comment Share on other sites More sharing options...
dougbgt6 Posted August 28, 2015 Report Share Posted August 28, 2015 Nice one Pete! There must be a reason there are more old Triumphs around than old Saabs? Link to comment Share on other sites More sharing options...
alarmman49 Posted August 29, 2015 Author Report Share Posted August 29, 2015 Thanks guys for all the comments, I guess that there is no hard evidence regarding K & N filters but as someone says the valances were put there for a reason so I might just put them back, thanks again to all, Tony. Link to comment Share on other sites More sharing options...
Clive Posted August 30, 2015 Report Share Posted August 30, 2015 Plenty of evidence that K+N's offer improvements over std air filters, BUT and it is a very BIG but, the vast majority are a waste of time and probably make things worse. If any modifications, like K+N's, manifold or whatever, it needs to be thought through and the knock-on effects sorted. If K+N's are fitted, they really ought to have stub stacks fitted inside to hugely improve the airflow (probably far more than just the filters). And of course, if you have more air, you need more fuel. So a change of needle and/or piston spring. All best achieved on a rolling road, although there are plenty of long-term recommendations for "standard" modifications. Cold air feed is also very worthwhile, along with good heat shields. I have seen k+n's fitted inside airboxes. In fact, on my vitesse, I had a modified std airbox with the K+N elements inside. No bling, but a case of function over form. Another option would be to use the std airbox empty, and connect the tubes to a remote filter placed in front/to one side of the radiator. Link to comment Share on other sites More sharing options...
alarmman49 Posted August 30, 2015 Author Report Share Posted August 30, 2015 Plenty of evidence that K+N's offer improvements over std air filters, BUT and it is a very BIG but, the vast majority are a waste of time and probably make things worse. If any modifications, like K+N's, manifold or whatever, it needs to be thought through and the knock-on effects sorted. If K+N's are fitted, they really ought to have stub stacks fitted inside to hugely improve the airflow (probably far more than just the filters). And of course, if you have more air, you need more fuel. So a change of needle and/or piston spring. All best achieved on a rolling road, although there are plenty of long-term recommendations for "standard" modifications. Cold air feed is also very worthwhile, along with good heat shields. I have seen k+n's fitted inside airboxes. In fact, on my vitesse, I had a modified std airbox with the K+N elements inside. No bling, but a case of function over form. Another option would be to use the std airbox empty, and connect the tubes to a remote filter placed in front/to one side of the radiator. Back reading so I would comment on the K & N's again.............I have K & N filters with sports exhaust and manifold, uprated the needles and springs and by all accounts have an extra 10/12 bhp ?? oh and by the way I'm 66 not a boy racer but do like efficiency............ have ordered the side valances because I like the idea of cooler engine/gearbox as it must push the air in that direction............... can you fir stub stacks inside pancake K & N's ?? I looked at them in the Moss book but couldn't decide.............thanks for your comments............keep 'em coming. Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 30, 2015 Report Share Posted August 30, 2015 Now idea, if the kn is open centre then stubs should be no problem, I fitted some to the Vit6 by cutting the stromberg std filter can , shorten the crush tubes to suit and and inser the stubs inside the paper element.... I felt they worked well pete Link to comment Share on other sites More sharing options...
Mike R Posted September 2, 2015 Report Share Posted September 2, 2015 I thought long and hard about K&N vs cold air feed. So I bought a temp probe from Maplins so that I could measure the air temp in the K&N whilst driving. Surprisingly it was around 40 deg C on a day where ambient was 18 ish when driving at 50 mph. The difference in density at those temperatures equates to around 2%. Not huge but worth having. So I've now modded my filter air box by welding a strip in to make wide enough to fit the K&N's. Whilst doing it I also changed the 2 stubs by welding in 2 pieces of old stainless exhaust - 50mm dia vs the original 35ish. The result is shown in the photo - if I can get the upload to work ... 1 Link to comment Share on other sites More sharing options...
Pete Lewis Posted September 3, 2015 Report Share Posted September 3, 2015 I used 1.5"plastic waste pipe to fabricate intake tubes on the Vit6 for a very cheap and far better than std smooth larger dia intake Pete Link to comment Share on other sites More sharing options...
rlubikey Posted September 3, 2015 Report Share Posted September 3, 2015 So I've now modded my filter air box by welding a strip in to make wide enough to fit the K&N's. Whilst doing it I also changed the 2 stubs by welding in 2 pieces of old stainless exhaust - 50mm dia vs the original 35ish. Great stuff! But have you measured what difference it makes to the temperature? Richard Link to comment Share on other sites More sharing options...
Mike R Posted September 3, 2015 Report Share Posted September 3, 2015 Yep - can't remember the precise numbers now, but was something like 15 deg c cooler (I think) at similar speeds - although not sure if the ambient temp was the same. I remember being surprised at how much difference it makes, at least in temperature terms. I bought an intake scoop from demon tweeks that I attached to the radiator side of the front grill, that means the flexi sucks the air from outside the car even when stationary. Link to comment Share on other sites More sharing options...
Alan C Posted October 1, 2015 Report Share Posted October 1, 2015 Hi Alarman 49 Sorry I'm a bit late to this thread. My GT6Mk3 has never had side or radiator valances fitted in the last 29years and I've had no problem with engine cooling. I'd partly disagree about upgrades-if they're done in conjunction with other mods then wothwhile gains can be made. I find the main advantage to K&Ns is that they literally last a lifetime. The filter element is cleanable with the special K&N fluid. So over the piece they work out cheaper than the standard units. Short stub pipes can easily be fitted-I've had them since I bought the K&Ns. I'd also disagree with the idea that an electric rad fan is not worthwhile. If this was the case we'd still see engine driven fans on cars today. Remember that today's driving is a completely different experience to that which was normal when our cars were built. There's much more stop/start motoring now and modern fuels tend to make engines run hotter. I've gone the whole hog and fitted a thermostatically controlled electric water pump as well. I've been glad of this combo on more than one occassion when stuck in long queues at the end of car shows. I've never suffered overheating unlike many of my peers in their standard cars. I've also fitted a thermostatically controlled oil cooler-similar to the ones fitted in later Mk3s. I realise that the GT6 has a more marginal cooling system than probably any other Triumph. Fitting a larger engine into what is essentially a Spitfire was always going to be a bit iffy with the limited space under the bonnet. So any help that can be given must surely be a good thing. Cheers Alan Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 1, 2015 Report Share Posted October 1, 2015 everyone loves or hates this topic, carburettors do require a stable air temperature to maintain mixture setting , going hot to cool as fans cut in/ cut out is not good for them an engine driven fan maintains a ventilated air flow under the bonnet al the time its running its better at this. KN are fine so long as you can get a needle to match the depression in the carb with its original spec developed by much testing by Triumph very few of us have the analysers or test facility to really get this right, because they make /allow more noise its felt they are better no they are often slower on the stop watch but ... the induction roar sounds good.. electric fans on modern cars has a lot to do with the engine faces the wrong way unless its Issigonis concept. just some ramblings Pete 1 Link to comment Share on other sites More sharing options...
Roymilburn92_3186 Posted October 3, 2015 Report Share Posted October 3, 2015 I have a Mk1 Spitfire with a Mk3 engine which ran very hot when I got it. I fitted radiator valances, the wider radiator, 7 blade mechanical fan and fresh coolant. No electric fan or engine bay valances and I have standard air filters. The car now runs a bit cold - just sits at the bottom of Normal even in traffic. Temp gauge doesn't get anywhere near halfway. I am now fitting a new thermostat as I suspect the previous owner tampered with it to try and keep it from overheating. I would like a bit more heat in the engine and in the cockpit! I think the condition and age of the radiator and the coolant have a lot more bearing in engine temperature than any other component or modification. I am new to TSSC and have picked up a lot of good tips from this forum - so thanks to everybody. Cheers, Roy Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 3, 2015 Report Share Posted October 3, 2015 If your mk1 has been fitted with a mklll you may have got the wrong temp sender not well up on spitty evolution but early non stabilised gauges (move quick as soon as switched on) Use 121997 and later stabilised (slow moving needle) use gtr108 many have had Hot readings and even changed engines because these have been inter mixed cross match the sender with the stabilised/not stabilised and they read hotter than actual just a thought when messing with hot readings std thermostat is 82c for uk use it must have a jiggle pin in the rim to allow air out when filling if its missing drill a 3 mm hole in the support rim or refilling will air lock. pete Link to comment Share on other sites More sharing options...
SpitFire6 Posted October 31, 2015 Report Share Posted October 31, 2015 Found this. Unfortunately its in pre-70s/ Old English/pre-metric AKA American temperature scale. -32 & divide by 1.8 to get Celsius. It suggests you really need an ambient air feed to your filters. My inlet temperature is around 50c in traffic- time to change.. Cheers, Iain. Link to comment Share on other sites More sharing options...
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