What Cam for B21 with ITB's

Jussi Alanko said:

You are wrong, usually they get more torque with longer intake manifolds in f-group rallycars, and this is not hurting the top end power.

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I mean, I'm not an engineer or a dyno expert, but I would tend to agree. Having worked on and owned a couple V8 cars in the past, I can vouch for the whole longer runner = more power idea. I'd like to assume something to do with velocity, but again, not an expert. There's probably a reason tunnel rams and crossrams are so popular, right?

Well I stand corrected. Though doesnt mean I wont find the facts. Post them if/when.
As I have a set of DCOE 45 #3’s that with some fitting, should work well. Albeit larger progression and jets etc as the are set for a 16. Was sort of thinking for the 23, but that might require the 50’s. So earmarked for the 21.
Velocity comes from many factors (not just plenum or trumpet), though I doubt this affects or has an effect of atomization.

h20ham said:

Well I stand corrected. Though doesnt mean I wont find the facts. Post them if/when.
As I have a set of DCOE 45 #3?s that with some fitting, should work well. Albeit larger progression and jets etc as the are set for a 16. Was sort of thinking for the 23, but that might require the 50?s. So earmarked for the 21.
Velocity comes from many factors (not just plenum or trumpet), though I doubt this affects or has an effect of atomization.

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You need to do some homework. It definitely helps with atomization and also with charge momentum. Longer runners help the charge to overcome the closing of the valve. IOW, it improves cylinder charge density.

mikep said:

No reply to a troll is the best approach. I’m over it all.
Besides, some of us are on vacation. I was driving home.

To answer his question , you can use wasted spark on any even-number 4 stroke engine with any overlap. It has been proven by the CVT toyotas and BMWs that run variable timing lift and duration. They crank that overlap in some cases to reduce pumping losses and for high rpm action.

Back to the OP,
My opinion is go with A, B, V, K, whatever you can find. Some other threads have info about newer grinds, and i might try one in a turbo engine. But the big cam companies might be ignoring volvo B engines because we are cheap and we share info. Some of the cams on this forum have really slept around.

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Only problem redblock 16v volvos don't have CONTROLLED VARIABLE TIMING and neither does a flagship T6 I do not believe. You saved the face and it wasn't a challenge for you to answer but at least I see whos in the rooms. You also confirm by your post that cams with valve overlap reduce pumping losses an make higher rpms possible. Your answer shows me that at least YOU do your homework and realize the issue with valve overlap of a radical cam and wasted spark . Sequential injection and ignition systems now have a home on turbo bricks as a result of this question. What a save someone unknowingly orchestrated for sequential fuel management and cdi ignition systems... "velocity stacks" with "bell mouth inlets" are also already definitely proven technologies for more power. There is nothing quite like the phone world where you need to ask slick questions to extract truth.... Outside it an elliptical bell mouth profile typically wins.


TTYL
Hubert

Jussi Alanko said:

You are wrong, usually they get more torque with longer intake manifolds in f-group rallycars, and this is not hurting the top end power.

Click to expand...

fatcatbestcat said:

I mean, I'm not an engineer or a dyno expert, but I would tend to agree. Having worked on and owned a couple V8 cars in the past, I can vouch for the whole longer runner = more power idea. I'd like to assume something to do with velocity, but again, not an expert. There's probably a reason tunnel rams and crossrams are so popular, right?

Click to expand...

It wasn't a runner/header tuning question. It was about why DCOEs specifically need to be close to the valve, which they don't.

Hi Mike,
I think his point was that stacks and long runners don't actually change the carb or injectors atomization and Id have to agree. Fuel Atomization and air charge density aren't exactly one in the same. It would seem that finer atomization could benefit the effects of cool rammed air much more effectively based on an increase surface area to interact with. One theory might be If it occurs further back that process has more faciliatory time to effect positive change. More than likely these different things will be merged all into one thing in the phone world versus isolating the separate pieces of the fuel and air delivery systems and seeing them for what they are. That creates misunderstanding and for some a point of contention.


Regards
Hubert

I think this encompasses both theories as you see the injectors are still at relatively factory locations despite the longer runners and elliptical bell mouth stacks possibly inside the plenum.

You also need perfect taper from cylinder head to carburetor or throttle bodies, it influences to flow of whole combination carb.>Intake mani->cylinder head...

Here is a finnish made intake manifold, from lvr racing engines:


those are good but a bit expensive.

You can also use these kind of fueling:



Those and megasquirt is very good combination.

But you need at least a 531 head with 48/40 valves, and 12.5-13.5cr if you want power which is comparable to turbos, original head and a or l or m or t or v or k or h cam and 14psi of boost. Thats make the same.

But 2.3-3.4 16v redblocks are damn good racing engines, those can make 400hp at wheels.
This engine is a f-group winner engine...


Here is a little peek to intake channel...
https://scontent.fqlf1-1.fna.fbcdn....=45e13ca5420757f55e450f3c595818b7&oe=60E205AD

Its a 2.3 maybe 270hp, at 2.5 it can make 300 and 2.8 it makes 340, and 3.2 or 3.4l 16v redblock can make a over 400hp and 400nm torque from 3500 to 8800-9200rpm. It have a very flat torque curve if all it's ok.

The numbers are really astonishing Jussi. Are the really large displacements a result of stroking as well as boring? Will such an engine accept high boost?. What you are showing makes me envious of what the Volvo scene is like on the other side of the pond, Glad to see the European tuners sticking it to them and showing us the real potential of the engines .... If you have other forums please share a link. If not here then privately Jussi. I definitely plan to spend a little change with your friends at SK

Thank you for your time and patience
Hubert