I hope yall brought some tissue paper with you when you came to this page!
You should try cleaning your self up a bit ;) |
Originally Posted by BMCRace
(Post 480058)
I hope yall brought some tissue paper with you when you came to this page!
You should try cleaning your self up a bit ;) |
i'm assuming that you could theoretically build one of these "backwards" for us fwd/awd 1.8 guys?
http://members.ozemail.com.au/~kevmo.../GTRengine.jpg |
Not quite catching what you mean by building one backwards.
I will say let me finish off all of the ones I am working on before I get started on new stuff already My current in order work load for intake manifold developing: Honda B Series Miata 1.8L Honda F20/F22 (s2k) Honda K Series Evo VIII Miata 1.6L Honda H Series Toyota/Scion As you can see we are still on the honda b series so it will be quite some time before I will be ready to take on any more as our list is already long and full of thankfully vary patient customers. When I am further along on these I would love to develop for many more motor types. We are just in a long process of re-gearing up our shop for high end intake manifold production rather than our already well known turbo manifold production. The reason we are pressing hard for this is because the turbo manifold market is so played out it is very hard to make any money in much less sustain a business off of. So instead of going the way of the dinosaur we are evolving and taking it to the next level where there is much less competition that has the same capabilities that we do. -James |
what i mean is, mazda/ford used the same 1.8 that is in the 94-97 miata in several fwd and awd cars. the block and head are the same, but the inlet on the intake manifold is on the opposite end of the plenum. if everything is symmetrical i'm thinking you could just put the plenum on "backwards".
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Well so far with what I have been working on for the Miata motors, the runners will have to be a curved runner because the market for the manifold will demand a similar to stock sized motor and rpm band tuned manifold so it will not be a modular design. It will be a solid welded manifold. However I can easily flip the plenum over and weld it on backwards if that is all that it would take to get it to work in your situation :)
-James |
that would do it :)
time to start saving up i suppose!! the plenum on the stock awd turbo manifold is TINY, which i can't imagine is helping me any when my torque curve plummets at high rpm. |
Lmao at the concrete comment, cant wait for new pics
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Originally Posted by BMCRace
(Post 480084)
Well so far with what I have been working on for the Miata motors, the runners will have to be a curved runner because the market for the manifold will demand a similar to stock sized motor and rpm band tuned manifold so it will not be a modular design.
Of course, folks like me want to spin 9,001 rpm just to stick it to the S2000's but... the point is a manifold with a power peak at 6800-7500 is not at all unreasonable, I spin my stock motor to 7500 without issue, the built one goes higher. |
Originally Posted by BMCRace
(Post 480080)
Honda B Series Miata 1.8L Honda F20/F22 (s2k) Honda K Series Evo VIII Miata 1.6L Honda H Series Toyota/Scion |
Originally Posted by Cspence
(Post 480103)
The 1.6 is pretty far down on the list
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But the thing that keeps the runners much longer is that you are talking about at max a 1.8L and very small cam grinds. Even a huge 380 duration cam grind would only be about a 1" difference over a 280 duration cam grind.
There are so many variables that determine the "calculated tuned rpm" of an intake manifold. The thing is not that I couldn't build one with a straight runner that you could use in a Miata, it is that if I did one with a straight runner for a 7500rpm max powerband we will be having to use the 5th or 6th wave to tune the runners to and by that time the harmonics have died down so much you will get very little if any harmonic charge to the air. I try to not go anything more than the 4th charge which is what the longer curved runner manifold would be, at this point it will still be a good kick in power, 3rd charge is better but we are talking a calculated runner length of a 1.8L reving to 7500 @ around 20" then which is obviously a ridiculous length... The theory is simple and sound and proven over 30 years to work by almost all automotive manufactures having having been put into effect by Chrysler ages ago. You want to use the least amount of wave bounces possible as you get a stronger harmonic supercharging effect, while still being able to package it in both economically and physically in your application. Pretty much my limiting factor in the instance of the Miata is the Shock tower. If I can't get my runner length by going straight out, I will have to either, use a different wave which will have a degraded harmonic, or use a curved runner to maintain a stronger harmonic, but it will have to be welded and thus no longer being modular. Now if someone decides they are willing to build a 10k revving 2L motor hear, it should be much easier to tune it to this, keep a straight runner, keep it modular, and package it all in the tight constraints of your engine bay. Also note that just because a motor spins to 9k rpm does not mean the manifold is tuned to hit peak trq at 9k rpm as this would destroy lower rpm power, especially when you shift it would have a major drop in power. What I like to do is find the total powerband of the motor, then depending on how the car will be driven (drag cars need high rpm power, road course need more mid range, street cars need lower rpm power) I will tune the runners to that application. If you rev to 7500 rpm redline, but you are on the road course and constantly shifting gears and only over 6500 rpm in the long straights it would be a waste of yours and I's time to tune the manifold to your peak 7500rpm power (unless that is your driving style, baby it in the turns, nail it in the straights...) so I might end up tuning the manifold to a peak trq at 6000rpm or even a hair less. See how all this can easily become a major cluster fck of stuff lol. Basically my intentions for the Miata motor will be to hit peak trq @ 6000 rpm as I am sure that is what the majority of you will be using this for. At the same time the manifold must flow enough cfm and have a plenum large enough to sustain your power after peak trq so that you do not get hp drop off (this is what happens when your either you do not have enough cfm flow into the motor, OR, when your plenum volume is to little for the power requirements) -James |
wow, I think ive been in this thread for an hour now, some cool ideas, I want to see some numbers and is there any chance of actual hp gain data with the b series? Not just what it makes on a fully decked out setup. Any chance of making a d-series design as well?
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If you thought the 1.6 miata was low on the list the d series is last place lol.
Eventually I will be doing 1 for just about everything. Yes we will have alot of dyno charts to post eventually, just takes time though. We have signed on a new distributor for us www.illgarage.com and he is more than willing to help us in our development of all products. I am headed home now so I will talk more tomorrow l8rs guys |
There's only one thing that confuses me (well, ok, one relevant thing) - doesn't a higher RPM peak mean shorter runners? Honestly, 6,000 RPM is probably close to right for a very serious street car. Maybe 6,500. I'm already upset at the idea of losing the variable reluctance manifold that's stock, but the large plenum is too good to pass up.
Out of curiosity, does more boost effect this? I guess the change in speed of sound with pressure isn't that high, but... at 1.5 bar positive pressure, wouldn't that shift your tq peak significantly? |
Yes the higher the rpm the shorter the runner. (remember we are only tuning the trq peak by changing the runner lengths)
As to the sound traveling at different speeds well see the theory was based on atmospheric pressures (14.7psi) so now when we turbo it, it becomes a controversial talk on how the air works. Some people say it scales proportionately, others say it just gets all out of wack so why even bother, and then yet others say the sound wouldn't travel any differently at all. I personally believe that it scales proportionality so what is good at atmospheric pressure will be good at 20, 30, 40psi pressure as well. If not anything else it is alot better than just rolling the dice to get your magic number to tune the runners to. This above^^ is the exact reason for the tune-able runners. You should be able to hop on the dyno with several different runner combination and really see what does best. |
Good at 20, 30, 40, meaning every ten, or you just mean under boost?
Adjustable runners would be awesome to do once - I guess with your non-welded manifolds, it wouldn't be that bad to make a series of runners and swap them out. If it DOES turn out to shorter with increased air pressure, you'd have a really awesome trick going on: TQ in the low end, out of boost, and tq at the top end, in boost. If it was linear with pressure, you're talking about 3,000 rpm (little to no boost) tq peak, and another at 6,000 rpm and 15 psi, etc. Self tuning manifold. |
http://bmcrace.com/vise/DSC02313.JPG
http://bmcrace.com/vise/DSC02314.JPG http://bmcrace.com/vise/DSC02315.JPG http://bmcrace.com/vise/DSC02316.JPG Here is another vise we did for the same company. Will be posting more intake manifold pictures soon as well as pictures of something for a Miata 1.8L ;) -James |
Hopefully something we can buy :) If you can get together a 1.8 manifold in the next few weeks I'd give a deposit to be first on the list..
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