Nobody needs or wants to prove you wrong and I feel no need to to defend myself against your BS. Anyone who reads this thread (or any other) can quickly sort those who know from those who think they know. If you wanted proof of anything I post you could have just asked. I dont say anything on these forums unless I can explain how I came to those conclusions (almost always based on dyno or datalogs). That doesnt mean I am always right, but it does mean I dont just pull s**t out of thin air and I am always happy to discuss ideas openly, which I though is what was happening in this thread.

Mate, sorry to say but in your short time here you have posted a lot of crap. Because of your attitude nobody will be bothered correcting you and you wont learn anything. Worst still others will learn the wrong thing from you which isn't a good thing for the forum.

Everyone is entitled to an opinion, but you should be open to the idea that yours might not be right.

LOL, wasn't expecting that one!


Wheres your fact?
You haven't posted one bit of proof for anything you've said!

From where did you spawn mate? I have to admit that Stockstandard and I didnt get off on the best foot when we first started discussing issues, however through discussions with him Ive learnt to respect his oppinions, even if I do dissagree. Stockstandard is a good guy who is trying to help, so cut some slack.

So in his defense, here is your reply.

You will nearly never find an equally lengthed exhaust manifold on street going cars, as they are too physically hard to fit. I know this as Ive played with a V8 supercar over the last year and even they dont run equal length pipes. However, they are stepped in different sections to optimise on the wave tuning of each individual pipe, so as to create a balanced effect. Now there is a couple of things to consider, unequal length pipes make your torque band wider as each cylinder runs on a different inertia tune and therefore act together to make a more driveable car. In the race cars they do try and keep them similar as they have targeted RPM's and therefore fatter torque bands arnt as crucial as on a race car as they are on a street car. Next is that within a length of pipe, you have 3 waves which act either together or not. You have 2 progressive waves and one stationary wave. When your progressive waves act out of phase then your stationary wave's amplitude is reduced to a relative zero effect, however on the other hand, when they are out of phase they double the amplitude of the stationary wave. Fact...... its the stationary wave that acts on your tuning more so than your progressive waves as it has a higher influence on molecular movement due to the combined forces involved.

Now this can also be applied to an intake manifold too as the theories are the same, just the wave velocity changes due to relative temperature. The fact that a log style manifold has a plenum is why it doesnt starve the back cylinders, it doesnt act as a single pipe due to the rapid change in cross section. The TB position has little relevance as it simply feeds the plenum and the plenum feeds the cylinders. When you have a plenum, depending on its volume, your scavenge will change. Its got to do with system balance. This balance is made up of several factors such as wave characteristics, gas volume & flow, and cam dynamics. I WILL NOT go in to such features as it has taken me years of research and R&D to work out what the go is with manifold tuning, however Ill leave you with this; V8 supercars must be s**t, cause they only have one mouth that feeds all 8 intake trumpets and therefore the front 2 cylinders would get all the air whilst the others would starve.

Mate before you start bagging out people on here, take your high school physics and shove it up your a***. Stockstandard doesnt need to be slandered by you as he has demonstrated that he has actually played with cars instead of being a text book warior like yourself.

OK, back to manifolds...



Not an easy question to answer because there are two forces at work in the BBM manifold. First, there is the helmholtz resonance, which is a fancy way of saying tuned rpm. This is changed by changing the duration of the intake valve. However, the resonance only works over a narrow rpm range and that probably isnt all that close to 3800rpm anyway.

The second force at work is just plain old runner length manipulation. Long runners build up more velocity, which means more swirl in the chambers and a faster burn, all the things you want for low end torque. Short runners however flow better, which is good for high rpm. IMO this is the primary force at work in the BBM. Any resonance will definitely give a little boost over a narrow rpm, but not to the extent of the each of the runner lengths.

I could measure up the runners on a BBM and do the maths to work out how much of a change a few degrees of intake valve timing would make, but really their is no real world evidence that suggests its a worthwhile.

What about the screw on the diaphragm how do I know it is correct. It looks like it has been moved when the cam went in.

Unlikely it was moved, not easy to move and no reason to move it.

If you want to set/check the position you have to apply vacuum to the diaphragm and set the screw gap to 0.05mm.

vibr8n, not sure what your getting at, but only being a member for all of a week and a half i'd shut my mouth and walk away from this one. and we dont just flame someone (anymore). sounds like your well on the road to getting a suspended membership

stockstandard is performance god, dont ask him if your going to disrespect him after

I'm not sure i would call him a performance god, but its crystal f**k clear he knows what he's talking about. And to abuse him, and call him a liar when he's offering someone he doesn't know the best of his knowledge is so far from what these forums are for, it's just pathetic.

Vibr8n, i don't care if you guys argue in debate, but keep the abuse down, it won't be tollerated around here.

Has anyone flow tested the log manifold and the BBM? The BBM has a more complicated flow path and it would be interesting to see if this has any adverse effect.

i'd be intrested to see the flow bench test, that was my arguement, not thats it is an arguement...

I asked an engine builder who had flowed them and he just said "they both flow plenty" with a smile on his face. Take that to mean what you like. However, any flow bench tests do not tell the whole story. For example, a BBM on long runners wont flow as well as short runners on the bench, yet it will make more power at certain RPM even though it flows less. Also flow benches are a constant flow, not pulsed like an engine so you cant measure any resonant frequencies.

The resonant frequencies also change with what cam is in there too.

vibr8n


Do you actually fix cars for a living? We want to see proof.
I would like to see some of your awards, achievements, etc etc before we should be believing anything that you have to say anyway? for all i know you could be just some 13 year kid talking s**t using daddys computer?
I want to see some proof that you have to fix cars for a living to know more than those that don't.
And before you ask, yes i am a qualified mechanic but I don't do it for a living. minimum wage isn't enough for me.

I am amazed that you consider yourself so much more knowledgeable than the rest of us at the ripe age of 21. I thought i knew it all at 21 too.

Look at the interviews at autospeed.com (this is proof) with Ford Australia's Gordon Barfield about the xr6 turbo and why they decided to remove the butterflies in the inlet manifold.
http://autospeed.drive.com.au/cms/A_1904/article.html


Forums actually need less people like you vibr8n, not less people like stockstandard.
The swearing & insults are completely uncalled for.

Anyways, regarding the manifolds, you can't argue with that fact that the fastest e-series car in australia is using a mpefi manifold, they can't be that bad. i just wanted to put in this FACT/PROOF.

you cant live the rest of your life relying on facts mate. I hear it hurts to get hit by a bus. i don't need facts, ill just go on hearsay.

I would love to argue with you all day/night.

i don't work on cars for a living a actually try to work on them as least as possible. i was just saying i want to see figures from someone who does.
i never said i was a mechanic or a performance god n i never made anyone digest my opinion just offered an alternative. which is what forums are for, discussion & like engineering,proving theories to create the best outcome in practical application.