TheRecklessEngineer Posted April 20, 2009 Share Posted April 20, 2009 I can route my air intake in such a way to get cold air (possibly ram air with some kind of trumpet), but it would be a PITA, going around the back of the engine and all the way forwards to the front panel. Much easier would be a feed from just behind the radiator. Is it really worth getting cold air? Would it have any real effect on performance/engine temperature? Quote Link to comment Share on other sites More sharing options...
TDEye Posted April 20, 2009 Share Posted April 20, 2009 Hi, I think this all depends on how tuned-up your vehicle is. For high-performance engines, forcing cold-air will more noticeably improve the engines efficiency, and (in my opinion) give a more satisfying engine noise. For standard engines their may be minimal difference if any at all. That said, my general rule when looking at things like this is to do what is optimal within the budget I have set myself, so as in the case here, if I could get it to reach cold air within my budget then that's what I would do. I have seen certain manufacturers such as AIRAID offer heat-shields with some of their simpler intake kits, although I haven't looked into one to fit a Land Rover yet. Might be worth looking into. Eye Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted April 20, 2009 Share Posted April 20, 2009 I wouldn't worry about it. Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted April 20, 2009 Author Share Posted April 20, 2009 Thanks fridge. Just what I wanted to hear. Now I only need 400mm of bling stainless air pipe... Quote Link to comment Share on other sites More sharing options...
Aragorn Posted April 20, 2009 Share Posted April 20, 2009 if its a TDI your intercooler is there to cool the air back down anyway. Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted April 20, 2009 Author Share Posted April 20, 2009 Its a v8. But Fridge is right - despite having a hairy cam, it's a pretty standard engine. Quote Link to comment Share on other sites More sharing options...
MECCANO Posted April 20, 2009 Share Posted April 20, 2009 Don't you mean cold water feed.... Quote Link to comment Share on other sites More sharing options...
TDEye Posted April 20, 2009 Share Posted April 20, 2009 I have to say that Fridge puts it much more eliquently. Pictures do say a thousand words. Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted April 20, 2009 Share Posted April 20, 2009 If I could do it without going out of my way, I'd put the inlet somewhere the air will be cooler. But I wouldn't make an effort to do so, not like it will make much difference anyway. About as much difference as my ram-top Safari snorkel does Quote Link to comment Share on other sites More sharing options...
missingsid Posted April 21, 2009 Share Posted April 21, 2009 I can route my air intake in such a way to get cold air (possibly ram air with some kind of trumpet), but it would be a PITA, going around the back of the engine and all the way forwards to the front panel.Much easier would be a feed from just behind the radiator. Is it really worth getting cold air? Would it have any real effect on performance/engine temperature? Surely more important for either location is the risk of water ingression? Neither behind nor in front of the radiator sounds a good place to me. Marc. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted April 21, 2009 Share Posted April 21, 2009 You could work it out. The benefit of cold air will be proportional to the temperature. At best, you'll go from underbonnet air at 80'C to outside air at 20'C, so the difference (in Kelvin) is 353/293 or 1.2, so you can allow a 20% increase in pressure drop in your pipe before you negate the benefit. To validate the temps, strap a min/max thermometer under the bonnet. This calc is true for race engines, lawnmowers and everything in between. It's more difficult to quantify the risk of water ingestion.... Sorry for bringing science into an otherwise interesting discussion! Quote Link to comment Share on other sites More sharing options...
Daan Posted April 21, 2009 Share Posted April 21, 2009 I believe it is worth it, after all it is a free gain. Daan Quote Link to comment Share on other sites More sharing options...
Troddenmasses Posted April 21, 2009 Share Posted April 21, 2009 I believe it is worth it, after all it is a free gain. Apart from the cost of the longer pipe, the time and @rse taken to sort it, and the possibity of actually making it worse by inducing a pressure drop in the slightly longer pipe. Stick with a nice short pipe and don't let the thing become asthmatic. Quote Link to comment Share on other sites More sharing options...
nicks90 Posted April 21, 2009 Share Posted April 21, 2009 you stole the words right out of the typing fingers troddenmasses. any gains you get from sucking in cold air will probably be negated by the longer pipework and extra bends in the system. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted April 21, 2009 Share Posted April 21, 2009 Did somebody say 'bonnet scoop'? Quote Link to comment Share on other sites More sharing options...
danielh110 Posted April 21, 2009 Share Posted April 21, 2009 I believe it is worth it, after all it is a free gain.Daan i have noticed that on mine (tdi) it runs much better at night wen it is colder than in the day wen the air is warmer, seems to use less fuel too. Quote Link to comment Share on other sites More sharing options...
nicks90 Posted April 21, 2009 Share Posted April 21, 2009 thats because your intercooler will be working better. my tdi feels much more perky in winter than on a hot summers day - an ambient difference of 20C means the intercooler already has a head start on cooling the incoming air. I also get less smoke under very hard acceleration which must mean its getting colder / denser air in the chambers burning all the fuel up. i really dont see the benefit of cold air induction systems in general though, especially on a petrol motor. Think of it like this... 3.5V8 cruising down the motorway at a steady 70mph is roughly 3000rpm? That means the engine is sucking in over 5000L of air per minute. There is no way the engine bay will heat that much air being sucked into it via the radiator and from down below and heat it up significantly. Plus factor in however much air is being rammed through the radiator at that speed (the rad panel is a BIG surface area). Might make a small difference if you are stuck in traffic at walking crawl speeds - but if thats the case, you dont need the extra power from cooler air anyway cos you're stuck in traffic! Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted April 21, 2009 Author Share Posted April 21, 2009 Hmmm...That got me thinking. According to this table: Air density table air at 20C is 0.075 and 80C is 0.063 or thereabouts. This is a 16% reduction in density. I might see if I can get cold air from somewhere more conveniant. Maybe a wing vent or similar. As for the water problem, it isn't going swimming (It doesn't have EDIS) and I've never had a problem before. Quote Link to comment Share on other sites More sharing options...
Daan Posted April 21, 2009 Share Posted April 21, 2009 thats because your intercooler will be working better. my tdi feels much more perky in winter than on a hot summers day - an ambient difference of 20C means the intercooler already has a head start on cooling the incoming air. I also get less smoke under very hard acceleration which must mean its getting colder / denser air in the chambers burning all the fuel up.i really dont see the benefit of cold air induction systems in general though, especially on a petrol motor. Think of it like this... 3.5V8 cruising down the motorway at a steady 70mph is roughly 3000rpm? That means the engine is sucking in over 5000L of air per minute. There is no way the engine bay will heat that much air being sucked into it via the radiator and from down below and heat it up significantly. Plus factor in however much air is being rammed through the radiator at that speed (the rad panel is a BIG surface area). Might make a small difference if you are stuck in traffic at walking crawl speeds - but if thats the case, you dont need the extra power from cooler air anyway cos you're stuck in traffic! I would like to dispute that, especially on an off roader. Crawling is often what it is all about, and then you really need it. On a petrol engine, you also have to consider ignition timing and the colder the intake air, the further you can advance the ignition. I havent brought any science in it because you dont need it; colder air is better. Quote Link to comment Share on other sites More sharing options...
Troddenmasses Posted April 21, 2009 Share Posted April 21, 2009 I havent brought any science in it because you dont need it; colder air is better. Yes, but more air is better still. If everything else was equal, colder air would be better. In this case, everything else isn't equal - the pipe run for cold air is longer and more convoluted. This will lead to a pressure drop, which will lead to a throttling of the engine. The greater the temperature difference between the air in the engine bay and the outside air, the greater the acceptable restriction. In reality, the air temperature won't make much difference because of pipework considerations and the fact that it is a very inefficient engine (all long stroke engines are - they aren't designed for high power, but for longevity) Quote Link to comment Share on other sites More sharing options...
geoffbeaumont Posted April 23, 2009 Share Posted April 23, 2009 Did somebody say 'bonnet scoop'? Not if it's going anywhere near deep water... Although James did say it's still got standard ignition... Best plan for the future though - he'll soon get sick of it playing up every time there's a bit of dew in the morning and fit EDIS Quote Link to comment Share on other sites More sharing options...
jacks906 Posted April 23, 2009 Share Posted April 23, 2009 Did somebody say 'bonnet scoop'? something similar to this would not be such a bad idea you get less pipe work (guessing it's on carbs) its basical there and ready i wouldnt expect huge gains tho especially off road as the low speed your not actually getting ram air or any colder air (depending were your existing air intake is) for example stick your hand out of the window at 10mph then 50mph then 70mph then 90mph etc faster you go the more ram you will feel and the colder the air will feel for off road i'd look at something to keep under the bonnet cooler an relocate it somewere out the way of sucking up any rubbish dave Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted April 24, 2009 Share Posted April 24, 2009 No no no Dave, you've missed the point. It's likely to give biggest gains at low speeds because the underbonnet soaks with heat, so if the engine can breathe cooler air and match it to fuel then you'll get more power. Your hand only feels cold out of the car window because you're warm. If you pass 15'C air over 15'C steel, no heat transfer will take place no matter how fast the air goes. (In fact, as the air speed approaches Mach 1 you'll start heating the steel but that's a whole nother argument!) For your engine, the answer to "Is it worth it?" is yes, if the temperature-related density increase is more than the pressure drop to get that air. For my example earlier, if you can move from 80'C air to 20'C air with less than 200millibar pressure loss (and assuming pipe and your time's free) then go for it. Quote Link to comment Share on other sites More sharing options...
jacks906 Posted April 24, 2009 Share Posted April 24, 2009 sorry i'm assuming the pipe work is already coming out of the side of the wing thus the air you are getting is out side temp and your trying to get a ram effect thus taking it to the front of the car if not i understand what your saying but then even at the lower speeds how ever the pipe work is fed the under bonnet temp (if anything like me mates efi v8) will heat the pipes then you come back to the same problem, that by the time it hits the intake it would be not far off original temp failing that could you not run a charge cooler for cooler air dave Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted April 24, 2009 Share Posted April 24, 2009 Not if it's going anywhere near deep water... Well I kinda assumed as it's not snorkelled it wouldn't be A Snorkel would of course sort out all the above issues, with cold feed, *some* ram effect at speed and no chance of water ingress given the other electrickery he has on it Quote Link to comment Share on other sites More sharing options...
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