5 replies to this topic

[nicklouse]

https://youtu.be/jba...mIm-i3NzIlwLn4w

well worth a watch.

 

will be interesting when he gets onto the 1275s 

[whistler]

Watched it yesterday. Very informative but would be interested in a wider study of cone v foam filters as well. Is it worthwhile going back to the Hawthorn or drilled air boxes for increased torque or power figures?

[coopertaz]

good video and agree will be interesting to see results for 1275. only one issue all testing was done with bonnet open ( i know the point was flow testing) but how will having it closed affect these results as holes underneath and towards the rear will be drawing hot air from rear of engine compartment. Holes at the front face getting cooler air, especially if a distributor guard is fitted as this will direct air towards the filter, would be the best!

Edited by coopertaz, Today, 10:05 AM.

[coopertaz]

Watched it yesterday. Very informative but would be interested in a wider study of cone v foam filters as well. Is it worthwhile going back to the Hawthorn or drilled air boxes for increased torque or power figures?

i remember the keith Calver article in miniworld that ken refers to and he did test the k&n straight onto the carb and found that removing the elbow on the carb inlet led to a reduction in low end torque, ram length change as referanced in the video, and only a couple of bhp over a drilled airbox at the top end. the reason i began drilling the front of mine in the first place.

[Ethel]

I don't think he's quite right about how filter flow restriction effects AFR, the carb venturi works on velocity "variable venturi - constant depression". It's the air's density that's dropped (fewer oxygen molecules by volume). Though a HS carb (at least) has atmospheric pressure, outside of any pressure drop caused by the filter, pushing fuel towards the venturi.

 

Would've been interesting to compare some of the factory improved cases & a bell mouth or ram pipe added to the original snorkel - that's what that case came with originally.

[ACDodd]

I have a part answer for you on the open vs closed bonnet effect. As part of the training I was delivering we did
That test, on this car peak power was reduced by 0.5HP with the bonnet closed vs open.

In an ideal world many things can be tested, but it takes time. Happy to do any tests that people want, however it needs to be funded, and that is where most people go quiet!
And trust me, if you can only get down to 4inhg of vacuum in the carb, fuel is sucked out of the jet. This is physics fact. This extra fuel is in addition to the normal Venturi effect.

Ac

Edited by ACDodd, Today, 04:31 PM.