Opinions - B18CR Bottom End with Alaniz head

[Chr1s]

I don't know what your aim for this build is, or what you will be using it for. I havn't taken the time to go back through posts to see what its about either, but going by the "crazy" comment you said earlier I assume you want a mental B series.

Internal combustion motors unfortunately are not as simple as they may seem. You need to have a very sound understanding of fluid/thermodynamics to even get anywhere before looking at the material and form of the components. What i'm saying is, what good is it knowing to run forged internals when you can't get the motor to flow the right way?

I already can see this leading to a kind of "headcase" of a build when I see that you want to use off the shelf parts. I don't like to look through a catalogue and pick parts out.

Since you asked about intakes, I beleive the intake should be designed around the camshaft, if you take some time and look at how the intake operates, beleive it or not, it's more than 4 pipes welded to a bigger tube; you will see that the camshaft has a great effect on the intake. So yes, if you want to get the most out of this motor, toda ITB's are NOT going to cut it, you will need a custom setup.

The way custom manifolds are made to spec is by some fairly complicated mathematics. It's very stringent on sizing, shape, velocities and flow to name a few. Helmholtz resonant frequency is a name you will learn to recognise. Not just in combustion engines, but also in audio speaker boxes for example!

To break it down nice and easy, the intake works on pressure waves, if it's easier for you to understand, picture it in a plumbing sense, since we use water to compare flow of air as a general rule of thumb at atmospheric pressures. The water comes down the runner, valve shuts, hits the back of the valve and a "wave" travels back up the intake runner and then hits the back of the plenum, this wave occurs again and guess what? travels back down the runner. Now this occurs many many many many times a second and at different rpm's as the RPM increase, so its not a linear function that we generalise on, but! We learnt in physics back in school that when two waves of the same phase occur at the same time, they join to create a superposition of the two. This generally increases the amplitude of the wave but keeps the frequency the same, so if you're tuning for x frequency @ x rpm, by tuning the timing when the valve will open with the fresh air charge and resonant frequency inside the current chamber you can create a ram air effect which is another name for "supercharging" the air into the cylinder. This is how intakes are made, now to get the optimum superpositioning of the one frequency charge you need a runner length that is impossible for the rpm range we deal with. We half the length of the runners and inturn we half the strength of the "superpositioning effect", we divide by 3, and we divide the strength by 3 and so forth. This is why the B18C2 has a dual runner setup, one for peak torque at high RPM and one for peak torque at low RPM.

All in all, I would go for a properly designed ITB setup with a plenum which is tapered to maintain velocity in the plenum for the further cylinder and of course, a proper high pressure zone cold air feed.

It's very very complicated, I will try and explain better later tonight, I'm just in a rush typing this so if any errors are in there, you know why .

Hope it helps you understand a little better!

[ewendc2r]

Hi and thanks for the explanation. I have a vague understanding of the dynamics of the air flow with respect that, vague enough to give a basic understanding. I realise that I will need to choose my velocity stacks carefully and that the length / diameter of the stack is designed to increase volumetric efficiency (I think thats what you are referring to? Isn't this how they can achieve greater than 100% volumetric efficiency for race engines? I am bit in over my head here .. So I am likely wrong lol .. But anything you want to share is welcome!

I would've though that once you have the ITB's that a stack can then be chosen based on your requirement (i.e. to improve harmonics for mid range or top end)? I understand the runners need to be quite long to tune lower rpm (which makes sense) but I haven't researched exactly how long (and as I don't know the mathematics etc, but I can look into it ...

One of the guys (geeang) @ clubitr seemed to get some very good midrange results on his motor?

[TODA AU]

So yes, if you want to get the most out of this motor, toda ITB's are NOT going to cut it, you will need a custom setup.

Good info but this comment is a bit harsh... LOL

But he was talking about OBX ITB's which are poor copies of the old (now discontinued) TODA 43mm ITB's.
The current TODA ITB's are actually an excellent product & would be more than up to the job covering all areas you have discussed.

Anyway,
What should be mentioned is for maximum output,
The intake ports will be the wrong shape to suit any oval port quad throttle system.
This will cause a power set & he'll be at a power deficit because of it.
This can be sorted with welding or resin, but is more work on an already ported head.


ewendc2r - You need to set yourself an end goal & back engineer the thing.

[tinkerbell]

ewendc2r - You need to set yourself an end goal & back engineer the thing.

yep, that is what is needed.

you can do it in stages, if you like,

but you still need an intermediate goal, then a final goal...

[Chr1s]

Adrian, I didn't know there is a new ITB setup from TODA, got any detailed info/pics?

I personally feel the motor should be built from the bottom end up, you can always swap around different heads and manifolds, but the bottom end is always going to be solid and a PITA to modify when in the car. Let alone expensive.

Question I have...I know some people don't like K series and all that, but if you are going to spend a large amount of money on a highly strung B series to make x amount of torque and power that we don't know the reliability of, why not go K series? They have motor sizing that will meet your torque requirements quite easily in standard application. General statement there.

[Benson]

Back engineer it maybe. But what happens when you dont meet your target or goal with the budget in hand? Will the OP need to throw more cash at it to make it all work? Why try something different when there is heaps of sucessful B-series combo's?


The best advice i can give you is READ and collect the combo's and builds in the Cammed Spec thread and the B-series combination on Honda-tech.com. All the information is there. Choose a build and power you want and replicate it! Easy isnt it?

And yes, geeang engine set-up is a good example of a simple build. He simply slap on A-sport ITB's with good headers and a good tuner to make it all happen. Who care's about peak power, the mid-range produced will be more or even to built b18c's.

[Slaz]

As Adrian said, having the budget and or goal in mind when putting the puzzle of this or any combo together is the way to go in this case but now a days when using stock parts ( when i say stock, im referring to head and block heights as V2V,P2V,P2H and deck height are affected ) as most shelf items can be strapped together and they accomodate most cams available off the shelf aswell, but if you were shooting for a particular comp ratio, piston/chamber design to compliment each other then you are having to work backwards as the head here is the item he wishes to use.

The old Toda ITB's would work for this set-up at 1.8ltr as i made 136KW atw's with my 1.9ltr combo, old 43mm Toda ITB's and that was only spinning to 7000 odd, but i personally believe bigger are better and would be for a 1.8 and the new units accomodate for that,the new Toda ITB's are great units, but require the head to be welding as its been said to take advantage of them as with most itb's done properly, a ported intake would flow the required to hit 140kw and be much cheaper and not require the head to be ported, just the manifold to the head and a suitable T/B matched to it.

Here is the Link to the new Toda ITB's on here Chris.

http://www.ozhonda.com/forum/showthread.php?t=101636

The K up front and transplant costs start to add up pretty quickly, especially if all the work is outsourced, as Benny and Jimmy have said and showed, some solid parts in a B20 yield good power, but the same parts between a 87.2 and 89 wouldnt be much, as its been said, its the bore that pays dividends which comes cheap with a B20, opposed to sleeving a B18 and going from there, but then some would argue on stock sleeve strength, some have luck, others dont, comes down to personal decison in the end, i think alot of motors come unstuck due to poor maintenance after they leave the builder or owners getting excited at the track or drags and asking to much of an engine that may have been built but not with the suitable parts and respecting its rpm limits, i dont think B's are that strung at those power levels when the parts match the application, its built right and maintained accordingly.

[Chr1s]

Some valid points Slaz

I would not call ~140kw high for a B series, I wouldn't even call 150kw high. It's a good figure to achieve, i'm not saying it's easy, but if I wanted to aim for a big B series, I'd be hunting the 200kw figure, as for that matter, I will be chasing that soon on standard sleeves. If it gives, it gives.

I have the feeling this guy wants to build a B series and be serious about it, in this case it would require some big research and heavy blueprinting work.

To the OP,

There is alot more to buying x pistons and using them in the block, there is certain clearances to be checked as a start and even then, I would modify the pistons to suit my needs. I find that there is a massive misconception about building motors and making power, alot of people think the most expensive parts and the best branded items will make power. The assembly plays a massive part in making power and reliability. Aside the technical aspect of manifold design and head design - probably the most complex and grey area to be talked about.

I see this thread turning into a technical analysis of the B series motor?


Benson: Albeit there is some good combo's out there making good power, not everyone is the type to follow others and the OP sounds like he is chasing alot of power/torque from the B series project - seems to me something a little more radical that no-one has really chased yet.

OP, can you please state your goal for this build?

[tinkerbell]

the OP sounds like he is chasing alot of power/torque from the B series project

nah, the OP was trying to take advantage of an offer on a "race head" from the USA...

i think he has since realised the folly of this path... (due to our combined input)

so i *think* he is revising his position...

[ewendc2r]

TB - Pretty much spot on.

Look, originally I had plans of building an NA build but realise the limits are around the 160kw mark and with considerable money spent IF that isn't enough (which I don't think it will be - more below) you have to start over basically .. However as I love the NA response etc I thought there may be a way to get a 'taste' of things to come if I committed to going down that path.

In terms of power levels, and noting that if I went FI it'd only be a roots style or a screw type blower (to retain the NA characteristic of the car as much as possible), I guess on a stock motor at 11psi (reliable except for the belt breaking / slipping) something in the order of 180-200kw@wheels with strong torque across the range. I feel that the chassis could handle this on a track but not much more really.. My theory is that with this sort of straight line potential and the already strong braking / cornering traits which will only be built on, it'd be an interesting time attack car in almost full trim. From there when the car is 'retired' for weekends only etc, I will rebuild the engine, strip car, change blower systems, go a little nuts etc.. Plus I'd get that gorgeous whine everyone time you press the loud pedal lol (

So now I'm re-thinking which path to take to reach my goal -- I do know where I want to finish. I'm trying to figure out the best journey on the way there.

The car just simply (as with a lot of the hondas, especially the nsx) is under-powered.. My goal is to make it a fast type r in anyones books really. I think 200kw would give it the potential to be a weapon and potentially too much, but its easy to change boost pulleys

[tinkerbell]

the AUDM B18C7 engine wont take 11psi of S/C boost with out ......
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you guessed it!!!!

rebuilding the bottom end!!!

[Chr1s]

I think a well prepped B20vtec will serve you well for what you are after.