quattro4now

http://www.dirtyimpreza.com/forums/s...5&postcount=38

Chaotic_FC

i'm not sure what you're referring to specifically...

if you mean how the pipes merge from 2 to 1, then its just because there are twin intake plenums, so naturally, there would be 2 inlets, and clearly the guy wanted them to merge back into one so it could feed back into the stock MAF and airbox.

t-von

iTrader: (8)

It may be an improvement over stock but, it could be alot better. It's kind of pointless for both TB intake runners to be sharing the same air flow meter. My 2000 BMW M5 is designed similar but has twin meters for each runner.

quattro4now

What I'm looking at is specifically is the split up airflow.

If I understand the concept correctly, dividing up the airflow well before each throttle plate creates a much smoother less turbulent path to the TBs (sort of like an ITB). This allows the engine to pull more air through the same TBs which then makes more power. Ideally the tubing has the same ID as the throttle plates' diameter so the only restriction is the plate itself.

I realize comparing the EG33 to ANY Wankle is comparing apples to oranges, but that intake supposedly offers a 20-30bhp improvement on a completely stock engine. Raising the power from 230bhp to 250-260bhp. Also this is with only two throttles whereas the 13b and 20b have three.

peejay

The 20B and 13B have only one. There's multiple plates but there's still just one.

I think the main problem with the SVX ducting is compromises made for NVH. It was a seriously undertuned engine, after all it was designed to be smooth for a luxury car.

The MAF is not a restriction, so it's not stupid to use "only one".

- buys his tires from Paul

quattro4now

True. I was fighting the sandman and lost.

I hadn't considered NVH. I'm sure the engine is under tuned, but still that is a large increase without additional mods and/or tuning.

There used to be a TB part for the LT1 that added a longer more gradual division of the twin throttles. The claim was a 10bhp gain.

I agree. Hell I'm not even looking at that or the airbox.

t-von

iTrader: (8)

Stupid and pointless are too different words. That AFM has now become the NEW restriction. Take Bernoulli's principle as an example. All the air that feeds into the engine is going through that air flow meter 1st. Then the air flow slows down because it now has to fill the volume of the split chambers (which have a much higher surface area than the AFM). Anytime you slow down air flow into a NA engine, you decrease it's ability to make more power. Look at any hi performance twin TB set-up these days (Ferrari, BMW M models, Lamborghini, ect) . Every last one of them has it's own AFM.

peejay

I would venture that the intake manifold and/or camshafts are the new inlet-side restriction, if they weren't there already. Screwing around with the MAF is shuffling deck chairs on the Titanic.

The only time to go to a larger MAF is if you run out of sensor range, IMO. We aren't talking about spring loaded flapper doors or a hydraulic air valve, here.

I understand what you're saying about airflow concerns, but the air isn't going to be moving all that fast. It's pre throttle body so it's going to be within a couple inches of water of atmospheric.

Heck, theory states that a single large pipe will flow better than two smaller ones because there is less surface area...

I know that the V12 BMWs have two AFMs because they have two computers. And that any engineering decisions made by German companies are suspect because their engineers are the epitome of ivory-tower engineering...

quattro4now

There are worse things than an AFM. CIS comes to mind in particular.

t-von

iTrader: (8)

Not doubting that at all. I was just purely taking about pre TB intake. And since were taking NA, every little thing makes a difference. I guess I'm just one of those guys that like to go the extra mile to make the little things work.