Jason Plato Posted July 14, 2001 Share Posted July 14, 2001 Dear all ....... I've been playing on the dual carridgeway today , attemping to determine if there is a significant difference in the air temperature at the air filter vs the ambient air temperature when at standstill , travelling at 40mph after 1 mile and 2 miles , then at 60mph after 1 mile and 2 miles and hence power loss or potential gain to be had . The car is out most weekends doing the Midland Speed Championship and I was trying to replicate the conditions prior to doing a timed sprint run . This usually involves bringing the engine up to temperature and then queing for about 5 minutes before going flat out for anything between 35 seconds and 2 minutes . My engine is 1600 K series set up with DTHTB's with an ITG filter , running without a hole in the bonnet . The exhaust manifold has insulation wrap . The temperatures were measured using 2 Comark air probes . One probe tie wrapped to the throttle cable sleeve coming out of the pedal box , which is directly in front of the filter/trumpets and , the second one tie wrapped to the front crossmember under the nose cone to measure the air temp entering the engine bay . Ambient air temp = 15C Engine temp on dash = 80-85C(Rising when stopped ) At standstill - engine running after 5 min : Crossmember temp = 19.5C Induction temp = 40.3C (Max) Travelling at 40mph after 1 mile Crossmember temp = 18C Induction temp = 29C Travelling at 40mph after 2 mile Crossmember temp = 16C Induction temp = 25C Then back to standstill , after 5 min : Crossmember temp = 18.9C Induction temp = 39.1C (Max) Travelling at 60mph after 1 mile Crossmember temp = 17.2C Induction temp = 27C Travelling at 60mph after 2 mile Crossmember temp = 16.3C Induction temp = 22C I then drove it all the way back down the dual carridgeway for 4 miles at around 70mph : Crossmember temp = 17C Induction temp = 21C SO ?? When I'm at the start line my induction air temp could rise to around 40C and it would only slowly fall to a best of 21C after 4 miles . Or more typicaly remain a minimum of 10-15C higher than the air which would be available if the filter / trumpets were sticking out of the bonnet(??) . My questions are : What is the potential power loss for this sort of inducton air temperature difference ? Should I try some ducted cooler air from the crossmember?, although this may not have much of an effect for say the first quarter mile ? What is the situation for those cars running enclosed / flat floors under the engine bays ?? How much does it cost and where can I have a hole cut in the bonnet for the filter ?? Or any other solutions ?? Dave Link to comment Share on other sites More sharing options...
Lennie Posted July 15, 2001 Share Posted July 15, 2001 When I ran my son in 750 roadsport we did some testing and found this to be good area to get extra horsepower.As we no longer do the series I can give you a mod we used to very good effect. Make up a airbox to fit against the scuttle where the heater would be and use the louvres for the heater as the air intake. We even went on to insulate the box. You can then run tubing from the manifold to the air box and have the airfilter inside. If you run a windscreen, as we had to, you also get positive pressure inside it. We never could work out if that meant we took away the high pressure area in front of the screen. First time out Jamie set an outright lap record at Thruxton against the 2,0 Vauxhalls, although we did have some aero tweaks which also helped,but I will keep them to myself. If you ever see a German race you can see they all have this arrangement, due to a very boozy night in the pits at Zolder.I keep that to myself as well!. Link to comment Share on other sites More sharing options...
Tony Martyr Posted July 15, 2001 Share Posted July 15, 2001 Dave, Air inlet temperature is one of the classic power correction parameters. If you use one of the power correction formulae you will be loosing over 3kW in the range you were measuring. However you need to consider the response time and position of your measurements. You need a PRT post throttle butterfly to get the induction temperture proper. Your engine will be sucking in about 80 litres of air a second during a sprint so the cooking effect of the bonnet space should soon disappear. But ducting must improve matters because it avoids the problem of re-circulation of heated air flowing over the exhaust on engine being drawn in as combustion air. In new enclosed engine bays it is a design problem that has to be solved. Look at the new mini etc. With the new ultra low emission designs you can't afford to pick up the smell of aftershave in the intake let alone oil vapour! Peugoet got it very wrong on one design which was good at pulling in cool air but equally good with water during the recent floods. Link to comment Share on other sites More sharing options...
Jason Plato Posted July 15, 2001 Author Share Posted July 15, 2001 Tony , I understand your comment that to measure the "proper" induction temperature you need to determine the air temp post butterfly , but wont this temperature be proportional to the temperature at the surface of the filter . That is , if you lower the temp at the filter surface by 20C then this can only help ?? The nearest I can compare is the "feel" of any engine on a cold winter morning vs a hot summer day . What is the bhp figure for 3Kw ?? Any way ........ whats the best way to chop a hole in the bonnet ??? Stick a formula 3 air box out the side , remove the restrictor ...MONSTER !!! teeth.gif Dave Link to comment Share on other sites More sharing options...
Mike Bees Posted July 16, 2001 Share Posted July 16, 2001 Interesting experiment Dave. For us sprinters it would also be interesting to see just how quickly the temperature falls as you pull away from rest. Personally I'm quite happy to take a bhp hit at the standing start, but it would be nice for full power to be restored within 3 or 4 seconds! Mike Link to comment Share on other sites More sharing options...
Roger King Posted July 16, 2001 Share Posted July 16, 2001 Mike, What may seem a bhp hit to you, still leaves you with twice the power of all the other poor sods. Link to comment Share on other sites More sharing options...
Mike Bees Posted July 16, 2001 Share Posted July 16, 2001 biggrin.gif Link to comment Share on other sites More sharing options...
Peter Carmichael Posted July 16, 2001 Share Posted July 16, 2001 Mike, Is traction control allowed in your class? Link to comment Share on other sites More sharing options...
Jason Plato Posted July 16, 2001 Author Share Posted July 16, 2001 Mike - The results were based upon pulling away from a standstill then cruising at 40 mph /60mph for 1&2 mins . I'm thinking of fitting a 4 bar electric heater under mikes bonnet during the sprint lunch break - I may find the 3 seconds I need then ??? CU@Curborough ?? dave Link to comment Share on other sites More sharing options...
Mike Bees Posted July 16, 2001 Share Posted July 16, 2001 Yep, I was just wondering whether the temp. comes down noticeably as soon as you start moving at a reasonable speed. 1-2 minutes is longer than most sprints as you know! I'm sure if you made the wire to the heater thick enough and bolted the plug into the wall then it'll slow me down adequately smile.gif Can't make Curborough I'm afraid, I'll be on holiday. Cheers, Mike Link to comment Share on other sites More sharing options...
Mike Bees Posted July 16, 2001 Share Posted July 16, 2001 No rules regarding TC Peter. So I guess I should have traction & launch control - but it rather takes some of the fun out of it. Mike Edited by - Mike Bees on 16 Jul 2001 17:07:51 Link to comment Share on other sites More sharing options...
Graham Perry Posted July 17, 2001 Share Posted July 17, 2001 Presumably if you combined high Induction temperature with high cylinder head/block temperature you would very soon start to lose serious BHP. Is there an approximate standard; a/ Induction temperature range b/ Engine water temperature range at which power is reckoned to be optimised ? Or is it a case of all engines being different. Link to comment Share on other sites More sharing options...
Mike Bees Posted July 17, 2001 Share Posted July 17, 2001 I would have thought that (a) would be "as low as you can get it". Mike Link to comment Share on other sites More sharing options...
TorAtle Posted July 17, 2001 Share Posted July 17, 2001 Dave, I have the temp sensor screwed into the inlet manifold (read after the butterfly) so can do some logging next week if you'd like. As Tony says this will show the real induction temp. At 70 degrees C inlet temp - what I've seen on a hot day - the ECU will decrease the amount of fuel by approx 6%. Tor Atle Link to comment Share on other sites More sharing options...
Tony Martyr Posted July 17, 2001 Share Posted July 17, 2001 Graham, there are standard conditions for the measurement of engine power and DIN and SAE formulae to correct power taken at different conditions. The more emission legulations take control of engine performance the more important these standard conditions become to the process of homologation The key to getting maximum power is to maximise the fuel density in each cylinder to do that you want both the air and fluid parts to be as cold as possible with the lowest level of other molecules such as water (low humidity). If you can suck up cold air and gain some ram effect then its all to the good. While you want cold fuel you want warm tyres - its a bugger isn't it? Link to comment Share on other sites More sharing options...
Mike Bees Posted July 17, 2001 Share Posted July 17, 2001 No problem at all Tony - just build a fridge around the fuel tank and duct it's hot air output to the rear tyres smile.gif Mike Link to comment Share on other sites More sharing options...
Mike Bees Posted July 17, 2001 Share Posted July 17, 2001 Wibble Edited by - Mike Bees on 17 Jul 2001 12:33:51 Link to comment Share on other sites More sharing options...
CHRIS CLARK Posted July 17, 2001 Share Posted July 17, 2001 Who makes this 'Wibble' 'fridge then? Link to comment Share on other sites More sharing options...
Graham Perry Posted July 18, 2001 Share Posted July 18, 2001 Ah, so a nice little (read big) nitrogen fuelled heat exchanger downstream of the carbs could be the way to go.(Or in the airbox of FI cars). Its a pity there isn't the room. Mind you I suspect the air on my car that is sucked into the engine via two 45's poked through the side of the bonnet is bound to be pretty cool anyway. As I have now also cured my Cross-flows habit of running at 110 degrees after only 3 minutes of 9000 revs, I guess that there is little scope for improvement now. Drat. Power feels good though. Edited by - Graham Perry on 18 Jul 2001 07:41:12 Link to comment Share on other sites More sharing options...
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