16v intake runner dimensions in 240

[HenrikGM]

Hi All;

Im working on a 245Turbo where im planning on using the 16v head, and want the engine in an upright position.
Im a bit worried though that my intake runner lenght suffers too much if im building a classic runner+plenum manifold, especially cyl4 is tight.

The purpose of the car is to build as extreme a turbo engine as possible, while keeping the joy in cruising with the car, so driveability is higher rated that big HP number if/when it comes to a tradeoff.

I could fabricate a curved sheetmetal intake with rather long runners, but that would cause non straight intake runners right away.

What is the better alternative here?
Short straight runners, vs. long curvey runners?
Will the better torque from the longer runners be eaten up by losses from non straight runners?

[Kadett4wd]

Bear in mind... as long no fuel is traveling in the runners the air has quite a bendable back..
You can bend the runners quite hard as long as it's only air.
long sweeping bends can in some places even be an advantage for making the correct swirl into the throat.

in a perfect world ofcourse there are gains with straight runners.

[johan johansson]

My old intake with straight runners and a 5 inch manifold - fits my brothers 240.
3-4cm clearence to the strut tower??

The only thing that didn't fit was the brake cylinder.

[Jan van Vurpa]

Hej Henrik, here is what one motor that we know was desined from clean sheet of paper to be a big bore turbo motor had for intake:


It was designed by some English guys who it seems every person on every forum is much smarter than but it doesn't seem like they were very much concerned with runner length..

On the other hand it sure seems like they were trying to manage air flow and help get it down the port:




And this seems to be fairly unique on a series produced motor;


maybe runner length is not so important as we think in turbo motors..

or maybe forum experts are smarter than those english who designed and made this.

Hard to say.

[HenrikGM]

The cosworth engine was perhaps designed from clean sheet, but im sure ease of manufacturing, and space confinements paly a major role for OEMs.

I could go nuts, and design a continous tapered intake runner with +400mm runner lenght, and it will be containing bends and tricky details.

On the other hand, does it actually give a wider torque curve, without hurting top end? My intuition says it should, but who knows?

By far the easiest approach is a short straight runner, but im guessing bottom end is suffering on that desicion.

Here it seems like excessive effort were made allthough im guessing whats inside:
http://www.dieselpowermag.com/features/ ... to_10.html

[HenrikGM]

Aother view of similar intake concept.

Very very long runners, if the plenum in fact is part of the runner, or just a design gimic?
http://www.evo.co.uk/front_website/gall ... ?id=360016

[Jan van Vurpa]

Point is that we know that resonances work like harmonics and that there is always whatever the hell its called "first order" "second order" "third order" etc.. And of course packaging for OEM fitment is always an issue, but think a bit. That motor and the whole car was concieved of with basically one goal and that was to beat Volvo Group A in Tour car raaces...
The goal was somewhere around 500 hk..

Do you really think they would make serious compromises in design for piddly things like brake servo or just junk in the way?

It's not like it was some lesser engine design house like BMW, Mercedes, Opel, ---all of whom went to the guys who designed THAT ^ motor when they needed a good head---since they knew who was better than them.

So I say, whatever--that works, the engine was famous as an amazing thing that worked real good, and is still first class..
What will you lose if you don't have the absolute-straight-from-the-hand-of-God runner length?
What will you win if you do?

The Roman guy Senneca said 2000 years ago "The Perfect is the enemy of the good"
Smart man..

[Kadett4wd]

Quite funny...
On almost all high hp Cossieengines,, the std inletmanifold is scrapped.

[muppo]

True kadett, even without hp, size of plenum to small, first bpu fit a plate to increase volume.
When it comes to runners length for GM application, no worries, if calculate from intake valve, U can easy get nice engine with around 300 mm or even less as long you keep some good design with plenum and intake to that.
You will use turbo and then I always prefer shorter runners.

Br,
MJ

[Kadett4wd]

I honestly thinks the cossie engine is a HUGE compromise.
Engine developed in the 70´s
Head developed for NA engines
misdesigned areas in runners(exhaust especially)
etc etc etc.

[Jan van Vurpa]

True kadett, even without hp, size of plenum to small, first bpu fit a plate to increase volume.
When it comes to runners length for GM application, no worries, if calculate from intake valve, U can easy get nice engine with around 300 mm or even less as long you keep some good design with plenum and intake to that.
You will use turbo and then I always prefer shorter runners.

Br,
MJ

Too bad you're so wrong on most of your dates. Pinto was designed in the 60s---before Redblock
Head developed in mid 80s expressly for WTCC and BTCC turbocharged motors...You may have read something---I have spent days at Boreham where I was for a series of long job interviews.. Have since 89 had nice long whole -afternoon chats with various of the key players in Ford in that time..

Sure it's a big compromise on intake side--EVERY CAR head is...there is simply not room in a car for runners to approach the valve in a optimal angle---I have to guess that you guys don't look much at the details of the heads of virtually any Japanese road motorcycle after who knows when but mid 70s onward, and especially by mid/late 80s... Very steep approach angle, beautiful short side radius---if you can call it that.. But if scaled up to car size the head and intake would be a meter out of the hood...

So sure its a compromise--but the point that you evidently missed or want to ignore is that it worked excellently both as a road race engine and as a rally engine.......even better of course when one is not locked into homologated parts and dimensions..
But it worked..

As so often on discussion forums it seems people mistake the/their "ideal" for "the only truth"..

If I'm not misttaken , wait let me check, Oh yeah here it is stackars Henrik sade;

as extreme a turbo engine as possible, while keeping the joy in cruising with the car, so driveability is higher rated that big HP number if/when it comes to a tradeoff.

It certainly seems to be a big compromise all that snack om "driveablity" so it SEEMS like fine nit-picking about idealt or theoretical värsta sorten insug längd till den sista tiondel" is just missing HIS point.


EDIT:
Kanske jag borde ha citerat din och den föregåande svar. äääsch, spelar ingen större roll.

[Kadett4wd]

Ohhh. Holy crap i was wrong with year of development for the pinto engine.
hope not your whole world fell apart for somebody not knowing pintos complete history.

As for the heads. I read in old magazine here in Sweden 'illustrerad motorsport' that the head were developed in the middle to late 70s as an upgrade for pinto in racingcars
but were put on the shelf as time went bad..(falkland war?)
It was meant for capris and formelcars in racing before turbo era.

Later on when Sierra needed a boost in power they just went back into the cosworth development shelf and used the head in rs500.

And before starting blowtorch again remember that the swede magazine could have been wrong too.

but this is the history as i know it.

back to volvo's.

rgds

[HenrikGM]

Well, im thinking this way:

Im not getting driveability with ultra short runners. They work fine for high boost high rpm, but doesent benefit the bottom end.

My target is to try and maximise the low end torque enough to maintain driveability(for effortless cruise), hence radical cams are out of the question.
This would mean to go for long intake runners and high port speed but without choking the port untill some 7000rpm.

Obviously it would be very easy to give the head 80mm straight runners and a plenum. Thats one alternative.

The other alternative is to raise the ports and simply build a high intake with long runners, and that could be inspirec by the peugot 908 engine. I could obtain intake runner lenghts in the 600mm range that way, if i wanted. It will need some fabrication, but thats just a matter of time to do it.

But my original question is what benefits the engine the most:
Long curvey runners to benefit the low end torque or just the longest "line of sight" runners that will fit the engine compartment.....

[Kadett4wd]

In low throttle openings i think the runnerlength has almost none value at all.
So if you need drivability in town with small throttleopenings,, do whatever pleases you
You see.. tuning is out of control when running lower pressure than atmosphere(absolute 1bar)
As the air has a total different density etc etc.

[johan johansson]

With my old intake i hade around 280-300 mm runner, and hydrolic cams.

That engine hade 400nm at 3500rpm on 0,6bar.

i think that was quit driveble.

more like crazy.