air intake

truckdoctor · Post by **truckdoctor** » Tue May 03, 2011 6:31 pm

My p5b sucks air in from under the bonnet consuming large amounts of HOT lighter air. Would there be any advantage in moving the air intake (via a hose etc. ) so the engine has access to cooler air from maybe the front vallance. Do you think it would improve MPG figures etc. As the car is used in the summer only I don't consider a problem with carbs iceing up, and am wondering if improved performance when it get's hammered ?
What do you think?

RoverP6B · Post by **RoverP6B** » Wed May 04, 2011 4:59 am

I own a P6B, and it too draws air from under the bonnet. I too considered the same, notably after the installation of my new engine. My main concern was the possibility that water could be drawn up into the engine during heavy rain etc. Although unlikely, the possibility is nonetheless real, and all it takes is just one occasion for it to happen and then the engine will be destroyed...literally.

So I decided against it. Doing this will also change the fuel/air ratio, so your existing needles will no longer be correct.

Peformance wise, there may be a tiny improvement way up the rev range, but how often does your engine spend there?

Fuel consumption,...can't say.

Sorry I can't be super positive, but as I say I have gone into it reasonably thoroughly, and for me it just wasn't the right choice.

Ron.

truckdoctor · Post by **truckdoctor** » Wed May 04, 2011 6:22 am

Not really thinking of any forced induction, just cooler denser air from behind the front valance or similar, this won't effect fuel mixtures.I agree regarding water ingress though so maybe some kind of water trap/drain could be incorporated. Modern engines take air induction from a cooler area so I guess there must be an advantage?

ChrisJC · Post by **ChrisJC** » Wed May 04, 2011 6:56 am

I suspect that modern cars can get away with it is because there is no carburettor to ice up. Cars like the SD1 had a thermostatic flap in the air intake to get air from either over the exhaust manifold or from the front of the car.

I don't see what harm it will do if you take cooler air from the front of the car, but I think the difference will be negligible.

Chris.

V8Smudge · Post by **V8Smudge** » Sun May 08, 2011 9:06 am

I seem to remember from when I did my City & Guilds, that the optimal intake temperature for carb efficiency (not power) is 38degrees. I've had a few cars with cold air feeds to the carb, always seemed more responsive, but always suffered from carb icing in cool damp conditions, to the point that I used to revert to the original intake during the winter.

Post by **Coops** » Sun May 08, 2011 9:35 am

my capri v8 is a right bastard to start in hot days, (as in 25C upwards air temp),

i ran a pipe from the intake to the front grill so the intake was out of the engine bay and the car started a lot better, i think im getting heat soak under the bonnet, never did before though,
so im thinking about possibly moving the filter, or boxing the filter in its current position from the engine bay heat (i know it wont stop the heat but must help? ) and run a cold intake pipe to the front grill, just like an OE air box idea, thoughts?

kiwicar · Post by **kiwicar** » Sun May 08, 2011 10:49 am

Hi Tony
Been on holiday??
yes I would box in the airfilter and run cold air from the front of the car, If you are getting heat soak you may want to put some louvers in the bonnet aswell to help the hot air get out.
Best regards
Mike

Post by **Coops** » Sun May 08, 2011 6:22 pm

nah not been on holiday mate,
nowt to do on the fopruim as it seems to be running smooth again (famous last words).
nowt to report on the car so kept quiet etc,