[JuniorB]

Kubrick's tuner pulled some good numbers, but mentioned there is more on the table, I still believe you can pull 325hp to the wheels with fbo, headers, tune, intake, and a good exhaust track. That sc is no slouch, we know the n52 can handle the power. That's were a good kit should be when your at 200rwhp. I'm sure others will agree that the 45-60 you get isn't worth the price. Two things I see happening here.... This is a bust, or ess sells out, and Bpc is booking custom tunes... I'm guessing the second.

[hassmaschine]

Originally Posted by dgaultiere

What is the argument for the n54 manifold anyway? Is the n52 single stage manifold somehow more constricted than the n54?

shorter runners for higher RPM power - but you already have that with the supercharger, you'd just be giving up the low end torque boost from the DISA stages.

[CobraMarty]

To help the needed low end power, wouldn't the long runner single stage IM work better than the 3 stage?

The 3 stage actually shortens the runner lengths with each DISA valve opening.
This isn't really needed as the single stage will flow more under boost and still have the long runners for torque.

The 3 stage will have a higher peak hp number but the torque curve will be lower across the whole rpm range.
Drivability vs dyno queen.

[hassmaschine]

No, because they are both the same length (actually they are identical except for the flaps). If that were true, the single stage would make more low end torque than the 3 stage, but it doesn't - because of the resonance tuning you get from the DISA flaps. the 3 stage makes more torque everywhere. There's no reason to believe a single stage would flow more under boost.

[Bob@BPC]

Originally Posted by hassmaschine

No, because they are both the same length (actually they are identical except for the flaps). If that were true, the single stage would make more low end torque than the 3 stage, but it doesn't - because of the resonance tuning you get from the DISA flaps. the 3 stage makes more torque everywhere. There's no reason to believe a single stage would flow more under boost.

The only thing I worry about with the 3 stage is the flaps break easily in an NA engine, I cant see them living a long life under 8lbs of boost. There are other options with building tq down low besides the disa flaps, and Ive built some good vanos maps over the years on the m54 with a S/C.

[hassmaschine]

I understand the concern, but I don't believe that they would actually see a pressure differential - if you look at the diagrams for the DISA manifolds, it's not like it seals off a chamber (it just reflects the intake pulses essentially) - both sides should always see the same pressure, so it really shouldn't matter.

[dancing__narwhal]

Originally Posted by hassmaschine

I understand the concern, but I don't believe that they would actually see a pressure differential - if you look at the diagrams for the DISA manifolds, it's not like it seals off a chamber (it just reflects the intake pulses essentially) - both sides should always see the same pressure, so it really shouldn't matter.

I'm no aerodynamics expert, but it seems to me that the velocity of the intake air would be more likely to damage DISAs than the boost pressure. Though perhaps the SC has effect on this too?

[JuniorB]

Well one thing we haven't seen is any n54 guy trying a 3si, lol. I'd be scared running 14psi with flaps.

[rjahl]

Originally Posted by JuniorB

Well one thing we haven't seen is any n54 guy trying a 3si, lol. I'd be scared running 14psi with flaps.

I think you guys are missing the point, The flaps never experience any boost pressure as the pressure is the same on both side of each flap. Resonate frequencies change when the flaps are opened or closed and its the frequencies that enhance air flow at different RPM's.

Study the diagram below, you see that any pressure forced in the manifold will always be the same on both sides of the flaps. You could put 100 PSI into this thing and the failure will not be the flaps.

[CobraMarty]

The DISA flaps change the Length of the runners to the head.
Longer runners = More torque, Shorter runners = Higher rpm power.

Low rpm in 3IM has both DISA valves closed and the runners are the longest. a 3 into 2 into 1 design. This is the same as the single stage intake.

Mid-Range rpm has the first DISA valve open and shortens the intake runner length and makes a bigger plenum and has the 3 into 2.

High rpm has the shortest runners. All 6 into a big open plenum.

It's about runner length not resonate frequency changes. Shorter runners flow more than longer runners.

Boost will make the 1 stage IM flow more, more in more out. Everything flows more under boost and higher pressure.

So the 3IM and the single IM will make the same low end, same long length runners. The 3IM will make more top end power with the shorter runners compared to the single IM.

I wouldn't spend the additional money to add the 3IM in this centrifugal SC kit as the high rpm loss due to the long single IM runners is made up with the higher boost.

[Cdutch513]

Originally Posted by CobraMarty

The DISA flaps change the Length of the runners to the head.
Longer runners = More torque, Shorter runners = Higher rpm power.

Low rpm in 3IM has both DISA valves closed and the runners are the longest. a 3 into 2 into 1 design. This is the same as the single stage intake.

Mid-Range rpm has the first DISA valve open and shortens the intake runner length and makes a bigger plenum and has the 3 into 2.

High rpm has the shortest runners. All 6 into a big open plenum.

It's about runner length not resonate frequency changes. Shorter runners flow more than longer runners.

Boost will make the 1 stage IM flow more, more in more out. Everything flows more under boost and higher pressure.

So the 3IM and the single IM will make the same low end, same long length runners. The 3IM will make more top end power with the shorter runners compared to the single IM.

I wouldn't spend the additional money to add the 3IM in this centrifugal SC kit as the high rpm loss due to the long single IM runners is made up with the higher boost.

I actually just picked up my car from ESS and they installed a 3im. Will post dunks when I get home.

[Cdutch513]

Here is single stage with single stage modified 330 tune. And then 3im with complete 330 tune

[CobraMarty]

Great results!! 302rwhp!!

You comparison shows exactly what I'm saying.

1IM and 3IM-longest runners -- same power 1500 to 2500/3000rpm
Both 1IM and 3IM have the same long runner length.

1IM and 3IM-first DISA open-mid length runners -- 3IM loses some power 2500/3000 to 4500rpm compared to 1IM
1IM has long runner length and 3IM has mid length runner length

1IM and 3IM-both DISA open-short runners -- 3IM makes more power above 4500 to 6800rpm
1IM has long runner length and 3IM has short runner length(which favors higher rpm gains)

[Cdutch513]

Originally Posted by CobraMarty

Great results!! 302rwhp!!

You comparison shows exactly what I'm saying.

1IM and 3IM-longest runners -- same power 1500 to 2500/3000rpm
Both 1IM and 3IM have the same long runner length.

1IM and 3IM-first DISA open-mid length runners -- 3IM loses some power 2500/3000 to 4500rpm compared to 1IM
1IM has long runner length and 3IM has mid length runner length

1IM and 3IM-both DISA open-short runners -- 3IM makes more power above 4500 to 6800rpm
1IM has long runner length and 3IM has short runner length(which favors higher rpm gains)

That was the first drive with the new manifold. ESS says after adaptations figure themselves out it will be about the same, maybe a little higher, in that dip range, and the high end might pick up some more. Next step is a meth kit and ESS will tune that and slap on the 110mm pulley.
Btw, the measured boost pressure and max boost with 115mm pulley is 6 psi.
Another btw, these pulls were in 118 degree weather.

[hassmaschine]

Originally Posted by CobraMarty

The DISA flaps change the Length of the runners to the head.
Longer runners = More torque, Shorter runners = Higher rpm power.

Low rpm in 3IM has both DISA valves closed and the runners are the longest. a 3 into 2 into 1 design. This is the same as the single stage intake.

Mid-Range rpm has the first DISA valve open and shortens the intake runner length and makes a bigger plenum and has the 3 into 2.

High rpm has the shortest runners. All 6 into a big open plenum.

It's about runner length not resonate frequency changes. Shorter runners flow more than longer runners.

Boost will make the 1 stage IM flow more, more in more out. Everything flows more under boost and higher pressure.

So the 3IM and the single IM will make the same low end, same long length runners. The 3IM will make more top end power with the shorter runners compared to the single IM.

I wouldn't spend the additional money to add the 3IM in this centrifugal SC kit as the high rpm loss due to the long single IM runners is made up with the higher boost.

actually, no - it doesn't. In fact, it's completely opposite.

It has nothing to do with runner length - the runners are always the same. What does change is the chamber volume. In Stage 1, the chamber volume is smallest. With both flaps closed, it's the complete opposite of a single stage (which has the same extra chamber as the 3 stage, but it's always open). In stage 2, one flap opens increasing chamber volume (and also resonance frequencies change), and in the final stage the chamber volume is highest (again with a change in resonance frequencies).

A single stage always has the full chamber volume, it's just like having "stage 3" turned on all the time. Technically, you could probably make the same peak power with a single stage, because stage 3 is basically the same thing (all flaps open, full chamber volume). But you could never make the same amount of power/torque at lower RPM (notice how torque is completely missing from that graph..); the flaps are optimizing the resonance frequencies & chamber volume for those engine speeds.

What you are saying is essentially that a single stage makes more low end torque, but that's simply not true. if it were, everyone would be deleting their DISA flaps for a low end torque bump..

[rick100]

Originally Posted by Cdutch513

Here is single stage with single stage modified 330 tune. And then 3im with complete 330 tune

nice numbers, I m wondering with proper headers how much more you will be doing .

[CobraMarty]

It's a variable 'runner length' manifold, not a variable 'plenum' volume manifold.

Longer runners make more torque. Shorter runner length makes more peak power at the expense of bottom end power numbers.
Look at 1IM vs N54IM. Long runner vs short runner. Look at the N54IM on N52 engine dyno graphs. Lose low end power and makes more top end power.

For the masses, all the soccer moms and commuters, and 98% who buy the 328 especially with auto trans, and hardly rev it over 3500rpm, a single stage intake with long runners is the IM of choice.

For the performance minded and stick shifters who rev beyond 3500rpm and to near redline, a shorter runner intake in the IM of choice. Look at the e46 M3 and ITB. It has very short runner lengths.

The best is a combination of the two. Long runners for low end power and short runners for top end power. Like the 3IM.

This is a different engine, V based, but it illustrates variable length runners and rpm range.

[hassmaschine]

No. Look at the diagram again. The runners are always the same length. It's the plenum volume that changes. When the flaps open they allow air to reflect off the closed intake valves and supply air to the valves that are open. The diagram is clear.

Variable runner length manifolds typically have two sets of runners as shown in your diagram above. the N52 manifold doesn't have that. It has a single set of runners, with two plenum chambers. The plenums affect resonance frequencies mainly. The flaps open and close the rest of the manifold to the two plenums to change the resonance of the manifold.

Also, the runner length of the single stage and and 3 are exactly the same. The manifolds are in fact identical except the 3 stage has holes for the DISA flaps. The flaps increase *low end torque*. I believe the increase in power for the "3rd stage" is mainly just tuning, because the 3rd stage is the same thing as a single stage (flaps open, full plenum volume).

The single stage makes significantly less torque below 5000rpm than the 3 stage. You've stated the single stages "longer runners" (which are in fact exactly the same) increase low end torque, but this is 100% reversed - the single stage makes less torque everywhere because the plenum volume isn't optimized by RPM.

You won't find a single graph of a single stage engine making more torque below 5000rpm after a 3 stage swap, because it doesn't - it makes less.

To illustrate, here's the DISA manifold at the 3rd stage (both flaps open):


Here's the single stage manifold. I removed the flaps because it obviously doesn't have them. The plenums, runners, etc. are identical.


Explain how you think it makes more low end torque.

[N52UNED]

[rjahl]

Originally Posted by N52UNED

Yes, it nice to watch two contributing forum members have a polite disagreement. Maybe not as entertaining as some of Axioms discussions but look where that got him.

[hassmaschine]

I'm open to the idea that perhaps the single stage has one of the plenums blocked (basically a "closed flap"). I'm not certain as to why the 3 stage cars seem to make more top end power, in addition to more low RPM torque. Maybe there's a cheap "single stage" mod where you simulate an open flap by cutting a hole in the plenum where the DISA would be.

I have another single stage I could cut up and see, but the last one I hacked apart I don't remember seeing anything inside the plenums that looked like it was blocking it.

either way the runner sizes, lengths, and plenums are identical between the two.

[JuniorB]

I thought this was already proven years ago?