Cold air induction
Discussion
HarryW said:
Slightly of topic, but here goes . The trumpet base has a water jacket for heating. Has anyone considered plumbing that up with a coolant system such as a air conditioning pipe feed or a bastardised fridge type thing to cool the air as it passes through the trumpet base
.
Feel free to laugh, but take the time to pass comment as well
Harry
There are two water heaters. One under the throttle body is often sealed off, if yours isn't it should be. The other is at the front of the inlet manifold. This one is harder as it connects the outlets from the heads to the thermostat housing. It's only a small chamber and probably not worth the hassle of trying to engineer it out, unless you happen to find yourself remanufacturing the inlet manifold for other reasons.
Yeah right.... NooNoo....
This was the throttle body that was originally intended for the engine in the first place. It was not ready in time so I used a ACT one for a few months.. I had this about 6 months before Tim's designs came out.
My experience of CF in this car is that is doesn't offer any better protection against heat soak than a well designed ally system. Several times the engine went into shutdown mode through heat soak problems and I had temps of around 90 degrees measured by the ECU! Albeit very hot days. Looks great and is a bit lighter but I had no end of heat problems which mysteriously went away when the ally system was fitted. The original design picked up air form the same place as the CF unit as well.
The air box was a later improvement, inspired by Pete Humphries and his efforts of getting cold air in. My own view is that sorting out the air intake so that you get cold air in is the key thing. Get that right and you can make the stuff out of anything... MDF, mahoghany, rice paper or what ever as the 5+litres of air per engine rev that flows through will keep things very cool. I can measure the air temp of the air in the plenum and there is only about 0.5 to 1 degree rise and that may well be differences in measurement so it works. Hammering around Goodwood and coming in with an air intake temp of 12 degrees and an ambient of 18 seems to say: yep got this bit of the design right.
Bonnet scoops were not allowed in the class and are notoriously difficult to get right without destroying the air flow. Having a scoop is no guarentee that the air will flow in anyway. The bottom of the windscreen is high pressure and does not do anything bad to the aerodynamics. It is about the best place but you need a lightweight bonnet with a big air gap at the back for it to work. The whole thing can be removed by undoing two clips which makes access easy.
The eight throttle body upgrade I am planning for the Winter may require a different installation yet again!
This was the throttle body that was originally intended for the engine in the first place. It was not ready in time so I used a ACT one for a few months.. I had this about 6 months before Tim's designs came out.
My experience of CF in this car is that is doesn't offer any better protection against heat soak than a well designed ally system. Several times the engine went into shutdown mode through heat soak problems and I had temps of around 90 degrees measured by the ECU! Albeit very hot days. Looks great and is a bit lighter but I had no end of heat problems which mysteriously went away when the ally system was fitted. The original design picked up air form the same place as the CF unit as well.
The air box was a later improvement, inspired by Pete Humphries and his efforts of getting cold air in. My own view is that sorting out the air intake so that you get cold air in is the key thing. Get that right and you can make the stuff out of anything... MDF, mahoghany, rice paper or what ever as the 5+litres of air per engine rev that flows through will keep things very cool. I can measure the air temp of the air in the plenum and there is only about 0.5 to 1 degree rise and that may well be differences in measurement so it works. Hammering around Goodwood and coming in with an air intake temp of 12 degrees and an ambient of 18 seems to say: yep got this bit of the design right.
Bonnet scoops were not allowed in the class and are notoriously difficult to get right without destroying the air flow. Having a scoop is no guarentee that the air will flow in anyway. The bottom of the windscreen is high pressure and does not do anything bad to the aerodynamics. It is about the best place but you need a lightweight bonnet with a big air gap at the back for it to work. The whole thing can be removed by undoing two clips which makes access easy.
The eight throttle body upgrade I am planning for the Winter may require a different installation yet again!
dickymint said:
Shpub,
Is it feasable to duct through the bulkhead?
Or maybe a fan in each pipe and a grille in the bonnet
with a cover to prevent rain coming in (opening at the rear therefore not a scoop)?
In a word no. To be honest, with a plain 350i the gains are not brilliant and it would be a lot of pain for almost zero gain. The more tuned the engine the bigger the impact though. The 90 degree temps caused the ECU to run the engine in shutdown mode and I lost about 100 bhp which is why I spent a lot of time and effort making sure it didn't happen again!Going from 360 (in that spec) to 260 is a big big loss!
Fans just get in the way. The bulkhead is a major impact zone so I would not advocate cutting through it and anyway there is virtually no room. Been there, tried it, gave up. The only way is with a low intake under the front, under the rad and into the engine bay but very susceptible to water ingestion and hydraulicalling the engine. Not a good idea.
shpub said:
Yeah
My experience of CF in this car is that is doesn't offer any better protection against heat soak than a well designed ally system. Several times the engine went into shutdown mode through heat soak problems and I had temps of around 90 degrees measured by the ECU! Albeit very hot days. Looks great and is a bit lighter but I had no end of heat problems which mysteriously went away when the ally system was fitted. The original design picked up air form the same place as the CF unit as well.
Curious this one, as on mobile tests that we carried out the CF plenums showed reduced air temp slightly, if you rest your hand on a CF plenum after a good few laps it should feel warm as apposed to burning hot with the alloy, I'm not disputing what happened with your car Steve , i guess every application is different, if i remember correctly the 520 picked up over 60 lb ft by going to multi throttle ? this makes me think that there was something else going on here and it must have been running with a high vacuum within the single CF plenum.
Tim
I think I'll buy some stripes and fluffy dice instead!!dickymint said:
so does my bog standard filter draw in air at 60MPH? 
>> Edited by dickymint on Wednesday 2nd July 13:21
The filter should have a larger x-section than the pipe, so it would be proportionately slower. 60mph estimate comes from 5 litre swept volume at 6000rpm ... 5 * 6000 / 60 / 1000 = 0.5 cubic meters per second swept volume ... assume that the pressure in the cylinder is roughly one atmosphere at the end of the induction stroke (is that fair??) ... if the air pipe has a radius of 8cm, then it has a x-section of about 0.02 meters squared ... to get 1/2 m^3 of air thru a 0.02m^2 hole, it needs to flow at 25ms-1 which is about 60mph
ATG said:
so does my bog standard filter draw in air at 60MPH?
>> Edited by dickymint on Wednesday 2nd July 13:21
The filter should have a larger x-section than the pipe, so it would be proportionately slower. 60mph estimate comes from 5 litre swept volume at 6000rpm ... 5 * 6000 / 60 / 1000 = 0.5 cubic meters per second swept volume ... assume that the pressure in the cylinder is roughly one atmosphere at the end of the induction stroke (is that fair??) ... if the air pipe has a radius of 8cm, then it has a x-section of about 0.02 meters squared ... to get 1/2 m^3 of air thru a 0.02m^2 hole, it needs to flow at 25ms-1 which is about 60mph
I would halve that volume flow because it's a four stroke. Assuming the air duct is 80mm diameter the area would be about 0.005 m^2, so the average speed is 50 ms-1, in the region of 100 mph. My guess is the volumetric efficiency is nearer 75% at high revs but whatever way you look at it that air's got to be moving pretty darned fast. At one point I tried to do the same calc for the air flow meter and worked out that the air would go supersonic at the equivalent of about 300 BHP.
dickymint said:
well,I drove to work in my pretty well sorted and original TVR 350i feeling the bees knees, and low and behold i just drove home in a "plain old 350" needing a driving lesson
If it makes you feel better... I still go for driving instruction. No one is that perfect that they can't benefit from some tuition.
danny hoffman said:
I always thought the a rising rate fuel regulator was the best way to spend under £200 (£70 ish I think) on a V8 Wedge
Danny
This is true. plus you get a ful tank of fuel and enough money to get slaughtered at a pub at lunchtime, and change for the missus!
Get one .. they really do work.
Well after all that discussion ive rung Pipercross who told me the only way to get a Viper is through my local TVR dealer!!!!!! I promptly told them that my local dealer wont even service a 350i so do you really think i'm going to buy anything from them?
It took me ten minutes of persuasion to get the girl to tell me that they don't make one for V8 anyway!
Ah well at least ive ordered a PBV.
Cheers all.
It took me ten minutes of persuasion to get the girl to tell me that they don't make one for V8 anyway!
Ah well at least ive ordered a PBV.
Cheers all.
Well heres an idea (bit of lateral thinking)
www.mantec.co.uk/index.cfm?param=Products/detail.cfm&id=933
www.mantec.co.uk/index.cfm?param=Products/detail.cfm&id=933
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