building an alloy plenum

[t5 pete]

Headache time
http://www.profblairandassociates.co...mouth_Sept.pdf

[claymore]

Without reading all that, I don't think it's as critical on a turbo engine as a N/A, I'm assuming that document relates to N/A engines?

[t5 pete]

[t5 pete]

Without reading all that, I don't think it's as critical on a turbo engine as a N/A, I'm assuming that document relates to N/A engines?

TBH I haven't started to read it but yes I would have thought so I will be going with bellmouths in the plenum tho

[claymore]

I think that casting will work fine, I'm using a late V50 manifold for the base of my new one, the runners are really short and just unbolt from the Plenum, interestingly there are no bellmouths on them.

[LiamT4]

Without reading all that, I don't think it's as critical on a turbo engine as a N/A, I'm assuming that document relates to N/A engines?

A couple of quick quotes from the site i posted a link to

"Application differences.

A key player in manifold design is whether an engine is naturally aspirated, or uses some form of forced induction.

Naturally Aspirated

Naturally aspirated engines tend to be far more sensitive to the smallest design changes than forced induction applications.

Forced induction.

Forced induction manifolds tend to be more forgiving than naturally aspirated manifolds in terms of their tolerance to design change. Boost pressure filling the manifold plenum typically keeps the engine well fed from the time it leaves the starting line until it shuts down."

[LiamT4]

As we know, what works for N/A doesn't automatically mean it will be beneficial for forced induction and vice versa.

[t5 pete]

I think that casting will work fine, I'm using a late V50 manifold for the base of my new one, the runners are really short and just unbolt from the Plenum, interestingly there are no bellmouths on them.

That is true none of the original have them but from what I have seen from builders they tent to use bellmouths

[claymore]

Yea, I'll be doing the same as last time and run a bead of weld around the inside then shape it.

[960kg]

That is true none of the original have them but from what I have seen from builders they tent to use bellmouths

As you can see it is all logic manufacturers don't need the ultimate but the tuner or builder does.

Airflow is airflow no matter where it comes from!

[t5 pete]

What do you use to weld colin tig or oxy acetylene

[claymore]

Tig mate

[LiamT4]

As you can see it is all logic manufacturers don't need the ultimate but the tuner or builder does.

Airflow is airflow no matter where it comes from!

Why do you use the exclamation mark so much! Its as though you're shouting all the time!

You do realise that there are differences in the way N/A and forced induction work? It does expalain a little on that link i posted, which you agree'd with.

[classicswede]

To answer the runner length to best power band here is a rule of thumb for runners

1. / One Formula: David Vizard's Rule for IM Runner Length

The general rule is that you should begin with a runner length of 17.8 cm for a 10,000 rpm peak torque location, from the intake opening to the plenum chamber. You add 4.3 cm to the runner length for every 1000 rpm that you want the peak torque to occur before the 10,000 rpm.

So, for instance, if peak torque should occur at 4,000 rpm the total runner length should be 17.8 cm + (6 x 4.3 cm) = 43.6 cm.

Vizard also suggests that you can calculate the ideal runner diameter by the equation :

SQRT [ (target rpm for peak torque x Displacement x VE)/ 3330 ]

SQRT = square root

VE = Volumetric Efficiency in %

Displacement in Liters


eg.

So if we want peak torque at 5800 rpm at 95% VE in a teg, VE = 0.95


SQRT [ (5800x 1.8 L x 0.95)/3330]

= 1.73 in. or 43.8 mm (1,73 x 25.4 mm/in.) is the ideal runner diameter.


I have always found info from David Vizard to be reliable

Here is some good reading that all reads right to me

http://www.team-integra.net/forum/bl...culations.html

you need to look at the info for FI (forced induction)

[960kg]

Why do you use the exclamation mark so much! Its as though you're shouting all the time!

You do realise that there are differences in the way N/A and forced induction work? It does expalain a little on that link i posted, which you agree'd with.

Obviously as you are not writing the post you do not know how i feel about what i write .........so also obviously you don`t know the explanation of the exclamation mark?

I agree with that link but what gets me is members like claymore thinks that nobody else knows anything and he even states that he can explain an opposite to every thing i say!

It simply has ALL been done before as the physics or whatever you want to call them cannot change just like in the post below.

I learned early in my tuning of motors that you don`t give away secrets otherwise you will never beat the opposition...why do you think even now F1 keep things secret.

Probably claymore is just trying to confuse the opposition instead of being truthful!

To answer the runner length to best power band here is a rule of thumb for runners

1. / One Formula: David Vizard's Rule for IM Runner Length

The general rule is that you should begin with a runner length of 17.8 cm for a 10,000 rpm peak torque location, from the intake opening to the plenum chamber. You add 4.3 cm to the runner length for every 1000 rpm that you want the peak torque to occur before the 10,000 rpm.

So, for instance, if peak torque should occur at 4,000 rpm the total runner length should be 17.8 cm + (6 x 4.3 cm) = 43.6 cm.

Vizard also suggests that you can calculate the ideal runner diameter by the equation :

SQRT [ (target rpm for peak torque x Displacement x VE)/ 3330 ]

SQRT = square root

VE = Volumetric Efficiency in %

Displacement in Liters


eg.

So if we want peak torque at 5800 rpm at 95% VE in a teg, VE = 0.95


SQRT [ (5800x 1.8 L x 0.95)/3330]

= 1.73 in. or 43.8 mm (1,73 x 25.4 mm/in.) is the ideal runner diameter.


I have always found info from David Vizard to be reliable

Here is some good reading that all reads right to me

http://www.team-integra.net/forum/bl...culations.html

you need to look at the info for FI (forced induction)

.....and there is none better than Vizard and he goes back to my Mini days of tuning and Small Fords also having articles in Car & Car Conversions. I still have one of his books.

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Yes, N/A is more critical for tuning but as i have said before whatever goes in general for N/A is also good for a blown engine.

Don`t forget boost in psi is NOT air speed.

[claymore]

Obviously



Probably claymore is just trying to confuse the opposition instead of being truthful!

WAW, why the hell would I want to hide anything when you have already stated on a previous post that I couldn't build a powerful engine so I had to put an extra engine in the car. I don't hide anything, on the contrary I post everything I do up on here, warts and all, your arrogance astounds me, but that statement certainly tells me the way your mind works.

Pete, my runner length is 31cm from valve stem to bell mouth, if that's any use to you, and as my on board videos show, you can hear the second power band come in at around 7k rpm

[960kg]

WAW, why the hell would I want to hide anything when you have already stated on a previous post that I couldn't build a powerful engine so I had to put an extra engine in the car. I don't hide anything, on the contrary I post everything I do up on here, warts and all, your arrogance astounds me, but that statement certainly tells me the way your mind works.

Pete, my runner length is 31cm from valve stem to bell mouth, if that's any use to you, and as my on board videos show, you can hear the second power band come in at around 7k rpm

Ha ha ha........i don`t call it arrogance, only yooooo would...Lol

I call it persuasive posting......at least you stating the 31cm length is a bit more help for Pete.....

[t5 pete]

Thank you one thing I will say unless your a business there should be no reason as to keep secrets on a forum as that is what they are originally intended for I for one have no knoledge on actually building a custom manifold to a correct spec or formula that's why I ask and as said a big thank you to people who have helped.

[oblark]

Did you work on any theroy regarding the size of your chamber or was it just a case make it to fit and then you worked out the ltr

My runners are 215mm long (thats from valve hand to plenum chamber.

[claymore]

So, let me get this right, David Vizard says shorter runners for higher revs, strange that, as that's what I said in post 2, then 960kg jumped in with his convoluted post to tell me I was wrong?