You need to look at restriction as a percentage, not a fixed figure. Also, the further up the rev range you go the more air the engine is demanding so the more the restriction holds it back.
What I mean is at low rpm zero restriction, mid range a little, then at top end a lot. You’ve also got IMRC which is changing throughout the whole range from 1000 to 7500rpm.
You can’t say that the manifold restricts by (say) 20bhp. The proof of that would be a 300bhp ITB engine wouldn’t make 280 with the OE manifold, yet a 220bhp engine would make 200 with it on.
Also worthy of note is that BBRs ITBs are actually quite small at 45mm. They will become a restriction eventually at around 250bhp.
I have already flowbench tested the two different inlets and there will be some articles coming up sometime about it. It’s just that as ever time and money slows things down because to put the whole thing out there I need to get a high output engine on ITBs and mapped with an aftermarket ECU.
If pulling the tube off at the bulkhead fitting allows unmetered, unfiltered air directly into the intake,
What exactly is the role of said bulhead fitting??
How it works I’m not sure as i’ve never taken one apart even though my car has one.
It’s interesting how it can transfer noise without letting the engine suck air in through it.
The best induction kit I ever had on a mk3 (I will tell you this now as I’m no longer racing one) was a ‘home brew’ cold air pipe that went from the fog lamp hole to the standard air box. The air box was ‘sealed’ so no drain holes etc…my theory was from the 1990’s suzuki ram air system & when I fitted it and logged the ecu, the ecu was seeing an increase of air flow grams per second above 60mph resulting in a slightly higher straight line speed with the induction over standard.
Obviously this was something that was not seen on a dyno…and the rules for racing said induction was free…lol
Great idea for a track car (cold and forced air) but I wouldn’t want to do it on a road car with the air inlet that low down and no water baffle/drain arrangement. Wouldn’t think that you would expect to be racing on a flooded track though so no problem in those circumstances.
It’s also on the wrong side of the car to be of much use.
At least one person did suffer from complete engine failure due to his Skuzzle sucking in (deep) water.
Pauls idea was great, but no good on a road car as the fusebox and headlight are in the way. Where it does score points (not just race points!) is that it was hidden from view so competitors won’t have seen it. That’s important in racing
Re sucking up water…
IF it was a torrential wet weather race I would disconnect the pipe to air box to prevent said problem as a few BHP loss wouldn’t matter in the wet
