Does anyone know what speeds you need to be up to in order to get near the figures quoted for bike engine output with ram air? I'm wondering if sevens ever reach those sort of speeds and hence if i can be bothered. Anyone done any testing?
If people have bothered, what sort of scoop/duct do you tend to use, and where on the car is this most effective?

I've heard a figure of 120mph quoted although that could be totla bull!

If it is true - don't bother!

Wyn

Some info here
http://www.sportrider.com/tech/146_9508_ram/index.html
http://www.sportrider.com/tech/146_9910_ram/index.html
http://www.sportrider.com/tech/146_9912_ram/index.html

Cold air is always denser than warm so ducted air from the front will be a. denser and be have some extra pressure than filters out the side.
On my CEC i have bike carbs and a pipercross, when funds allow i will get one of there airboxes and pipe cold air from the front or a bonnet scoop.
every little helps and cold air makes a lot of difference compaired with hot under bonnet stuff

Ok, so that one can go on my post-sva "when i can be ars3d" to-do list.

Thanks folks!

The effect is not only good but can also be very negative on a bike engine in the wrong conditions. I had twin ram intakes on my GSXR 600 and 750 a few years a go and it would cause carb icing on cold mornings resulting in loss of power and in extreme conditons stalling. If the bikes were used during the winter I would have to blank one off thus restricting the cold air intake and some of the performance ( noticable at higher speeds). My current bike is a zx12r with fuel injection and is not affected in any weather conditions. The speed/wind effect required to make a perfomance gain noticable is well on the way to sending you to jail and well out of reach of more standard 7 style cars.

Hope this helps

This is currently on my list if things to figure out too?? So would you say a sausage filter in line with bonnet scoop with a cold air feed would be a good way to go.

Will be running a ZX12 and seem to remember reading on Hellfire's site somewhere they had heating issues?

quote:

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Originally posted by eznfrank
This is currently on my list if things to figure out too?? So would you say a sausage filter in line with bonnet scoop with a cold air feed would be a good way to go.

Will be running a ZX12 and seem to remember reading on Hellfire's site somewhere they had heating issues?

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The zx12r engine runs fairly hot all the time, for the size of engine the oil capacity was kept low to reduce weight. Even in the bike when riding through town the fans kick in very quickly compared with say a blackbird engine.

I think this has been looked at before.
I think the general consensus is the ram air effect kicks in well after your standard 7 has hit the aerodynamic brick wall!!!!!!!
Good on a 200mph bike though (I was told it starts happening at 130mph+ as a rule of thumb)

I am using the standard airbox which will have a small plenum added to the filter opening with 2 X 3" tubes sticking out.
My engine is mounted the same as a bike at the rear end of the Motaleira.
From either side of the seats there will be two NACA ducts (one either side of the car) piped in 3" flexi to the airbox.
I believe that using the original airbox is a bonus and the ducting can only help.
Because a rolling road cannot simulate airflow as the car is static, I have invested in a power commander and an inovate lambda gauge.
This will enable me to tune the car in the "real" world, while I am actually driving.
Rescued attachment fuel filler 4.jpg

Like kevmcdo says, you'll not be able to reach the speeds required to benefit from ram air.

Phil

If you use a forward facing bonnet scoop, don't forget to ensure that the air flow under the bonnet is retained. The air flow through the radiator will be reduced if too much air comes in that way 'cos you get the same pressure in front and behind the rad, rather than just high pressure at the front only.

if you had a bigger input volume of air and focused it down to a smaller diameter. this will have the same effect as going faster.

Its normal to see this on big sports cars.
The trick is getting the fueling right cost loads of money