[RESOLVED] Tuned intake manifold

[Evilimports]

Has anyone come across a tunned intake manifold ( i.e. equal length runners) for a 2nd gen eclipse? And would it even matter since the manifold would be pressurized under any power demand?

 

[jrohner]

The stock ones have 'equal length runners'. That term is usually used on exhaust -- headers actually.

 

[VETTE_50_TH]

He could be referring to an intake that breaks up from the Tb to the runners evenly rather than having a plenum to "hold" the air. Kind of bad terminology but you understand. I have never seen one and not sure how much it helps either.

James

 

[StavRedline]

I have seen a few stock engines that come with equal length inlet runners actually, but never an aftermarket inlet for a car like it.

And yeah, they do kind of resemble a tubular header.

It would give equal airflow to all cyls, which is pretty damn rare on most engines, which would mean ECU mapping would be a lot easier and eliminate the usual situation where one cyl is always the one to melt as it gets more air than the rest.
The obvious solution is use individual cyl trim to increase the fuel to whatever cyls need it more than the rest, but that would mean either a bit of guess work, or EGT/AFR sensors on each exhaust runner to get it totally accurate.
Hence why most just run it all safe.

 

[Evilimports]

To clarify equal length, i mean an equal distance from the tb to all the cylinders. I guess the runners are equal length an oem manifold but there different distances from the tb.

 

[StavRedline]

To be honest mate, youd be very unlikely to find any intake like that, barring the ones I mentioned (It was on some crappy 4cyl n/a suzuki IIRC).

Often manufacturers taper the plenum as it gets further from the TB to it makes flow more equal, but as 99% of them stock or not are log style, its very rare they are proper equal length like some headers.
Mostly due to it not giving any real gains, barring making getting the fueling safe/accurate far easier.

You will usually find most big plenum aftermarket inlets are higher flowing but far LESS equal than the stock intake manifolds (no matter what they claim! )

 

[VETTE_50_TH]

To clarify equal length, i mean an equal distance from the tb to all the cylinders. I guess the runners are equal length an oem manifold but there different distances from the tb.

Thats what i thought you meant. Yea, man, i havent seen anything like that before.

James

 

[BoostFrenzy]

Very interesting idea. It wouldn't matter too much on a pressurized system but it could have its benefits. I think of it like this: On the 2JZ engine, they want a LARGER plenum such as ones Veilside and Titan have made. And since they run big numbers and have not had a problem, we shouldn't want to get rid of the plenum either.

 

[kronus]

I was under the impression that the distance from the TB to the actual intake port is not as important as having the velocities at each of the intake ports as close to equal as possible. That's why most 'street' SMIMs are tapered. Typically the cylinder furthest away from the TB suffers, so aftermarket manifolds are tapered to remedy this.

 

[Defiant]

There's half-a-foot of "tuned" runners heading into the head on the stock intake. With fuel injection, the motor's not so concerned with where the throttle plate is. Pressurizing the intake tract also reduces the payoff for intake tuning, other than when running off-boost.

 

[pboglio]

The packaging for a DSM would be difficult.

 

[gixrman]

The GM quad4 had a tuned intake.

 

[WIDSM]

Individual throttle bodies would give you that equal length. I wouldn't want to see the piping needed for that on a turbo car though.

 

[GSeX02]

your not going to find it if i had to make a bet