Ram Air for Clio 172 Mk2

[ChavyBoy]

OK I not one for modding as my car is bog standard but I am interested into what people think.

If a ram air system was to be created for the 172 would it make any gains of bhp ?

What I have been thinking about is something Bigmoose said to me on Saturday night regarding the Cliocup ram air scoops.

Aparently you can get these which scoop in air and because you are going from a big scoop into a smaller pipe would this flow air through quicker also making the air forced into the inlet chamber at speeds ?

Any ideas ? I know it would really make a difference at low speeds cause the air isnt being forced in but what about high speeds ?

 

[Simon172]

Hi, I think the Captain and Nick had a big ol discussion about this a while back - cant remember what the thread was called. Try doing a search on ram air. I doubt youd notice the difference to be honest. I think youd have to be doing over 150 mph to benefit from any gains from a ram effect. Or am i wrong? who knows? certainly not me, im only a musician who loves clios! If its noise youre after, take the cold air feed pipe from the connection to the wheel arch and unleash the beast within....

 

[Anders]

Yeah Chavy, you are opening a real can of worms here matey. The logic says yep it is possible to create a higher pressure of air to simulate forced induction, but the speeds you would have to be doing to gain any significant benefit are up for discussion. Plus the aerodynamic alterations to your car would have to have to do it properly would be quite a job.

Knowing bikes as you do you could try and copy the ram-air effects that the superbikes use.

 

[ak_uk]

I think the Capn and Nick agreed to differ!




ak

 

[Simon]

The main benefit is the Air will be colder if it is drawn from outside the car than if it is drawn from inside the car. Colder the air the bigger the bang.

 

[Nice Try Good Bye!!]

I have such a project ready for testing this weekend, no cutting of holes etc needed just remove of the front nearside wheel and plastic guard to fit it, will let you know the out come as soon as I note a inprovment

 

[Fred@BTM]

No arguing about whether RAM AIR is possible on a 172 please!!!!! (Nick + the Captn)

 

[tomboy]

We had ram air make their first one for us, and they took it down to their roling road. It LOST 4 BHP on paper (the car was not moving therefore no ramed air) but on the road it did seem to gane a bit, not a lot though. However it dose sound nice though, espesally as we got it for free!!!

 

[ChavyBoy]

Anders,

The RAM air on a Ninja 600 (2000) model uses one massive port in the front fairing which is then fed into the airbox. If you disconnect the pipe and have just a normal feed into the airbox the bikes power is well down, so I think it may work in the car as well !

Also the scoop is massive on the bike (About 7" by 2") but goes into a pipe maybe 1.5cms in diameters to "RAM" the air in.

 

[bigmoose]

This is where I think that my idea may work!!!! (I am not technical though)

The idea that I have is that of....

1. Get Clio Cup front Splitter
2. Cut centre section out
3. Fabricate large scoop to fit in gap left
4. run it through to thin piping to create a ram effect.
5. Get a bonnet with vents in to release warm air.

It may work, but we shall see. I have the pipework made up without too many bends in it, and I am getting the measurements of the splitter so that the scoop can be made, and as soon as the splitter can be purchased from Renault, it will be rushed to the bodyshop to be butchered. All I neet now is the bonnet of the 1600 race car.

 

[Nick Read]

Well I can say that with a 7"x2" forward facing scoop that feeds a two foot long 2.5" diameter pipe up to the airbox, with two gentle bends in it - which is the system I run - I get a definite detectable increase in airflow into the engine at above 75mph. In fact I see *so much* boost that if you open the throttle more than halfway (on a 16v there a 2 throttle plates, the 2nd one starts to open after half throttle) at 75mph+ the air/fuel ratio goes totally lean, almost off the scale, through a lack of fuel in proportion to the air intake.

This suggests that the boost is more than the stock ECU can cope with (even when chipped for more fuelling as mine is) and the only method that I can use to keep the air/fuel ratio right is by physically turning up the fuel pressure as well to match the air. And as you know more fuel+ more air = more power.

Joes argument (I think) is that you need F1 engine and aerodynamics technology to get it to work and even then it wont be until 150mph. My results show otherwise, that in fact it can be made to work at 75mph on a normal road car. I would suggest that if you are serious about putting in a ram scoop you think carefully about fitting an air/fuel ratio meter as well.

 

[ChavyBoy]

Nick see my point about my old Ninja 600 as well. The air scoop is necessary for this engine so it does work.

 

[telford_mike]

Isnt this exactly what a PiperCross Viper reckons it can do? Or am I missing something?

 

[Simon172]

Heres some good info (lifted from this webpage: http://www.adapco-online.com/user_arts/werner/

FRONT END AERODYNAMICS - Various front end configurations were simulated, in order to determine how the external flow was affected by the internal flows through the airbox, brake and engine cooling systems. Different internal flows were considered, starting with a completely closed front, which of course is not feasible. It was assumed that the vehicle moved at 250 km/h and that the engine was running at maximum rpm (approx. 12.000 rpm). Fig.8 displays the normalized pressure distribution in the symmetry plane. Clearly, the internal flows led to considerable changes in the front end pressure distribution. In particular, the low pressure region at the front of the hood (case 1) almost disappeared when the internal ducts were open (cases 3 and 4). This effect is more important for racing cars than for ordinary passenger cars, as racing car engines operate at higher rpms for a given vehicle speed so that the ratio of the air flow through the airbox to the external flow is much higher.

http://www.adapco-online.com/user_arts/werner/fig08.gif

 

[BenR]

hmmmmmmm, maybe me and capt should enter this.
haha!

no the theory works but in principal not so much.

your engine is consuming roughly 6300lts of air @7000rpm.

the ram effect would have to suply 6301lts to provide any possible "ram air effect"

can you design a system which does this?

as capt would say, even f1 has trouble utilising ram air....wouldnt they make that intake a damn sight larger so it could inhale or ram a larger area of moving air....the more air you can fit in fer min, the higher the pressure inside the box will be, effectively....
but that dont, cause air to the rear wind is of much more benefit than the 3hp it would gain.

the viper kit although they say uses ram air, its main benefit is the location of the intake outside the engine bay....

my 2p

 

[Simon172]

Its a Calibra by the way. "These results demonstrate that the internal flows must be taken into account for an accurate prediction of the front end flow".

That study on the web page given previously is relevant to what weve been discussing.

 

[M.C.]

Not made my mind up on this yet, but think about it a different way.

The ultimate aim in tuning an inlet tract is to reduce restriction as much as possible. As the engine sucks in air it will cause a vacuum, and will have to work harder and harder to draw air in from around it. So this in itself is a restiction. Now if you are ramming air at the inlet, it might not meet the needs of the engine exactly, but it will help the engine to some extent. Try sucking water through a hose pipe, then attach it to a tap, turn it on and suck again, tell me which is easier. Instead of scavaging for air, there is a plentiful supply, and the engine must be able to draw slightly more in? Its the same principle as fitting a free flow panel filter. The engine encounters less resistance to air flow. Not saying how much it helps, but Id guess that the benfits of power gain would not be outweighed by the aerodynamic disadvantage.

This could be complete tosh as Ive never experimented, but surely vauxhall wouldnt have gone to all the trouble they did to rotate the head on there TC if it doesnt help at all, and it was a lot of trouble for them to do it.