I wanted to start this thread with the hope of motivating someone out there to
do some R&D on a New Intake Manifold for the RX-8...

We are starting to produce some decent Power with the turbos now, that I'am hearing that this is a lodgical move.

If you take the time and look at the plastic intake manifold and the contour of it's
shape, It looks as if we can improve on that design for Better Flow, which should
help make more power for both Forced air and Na Renesis motors.

I look at the 13b,20b's intakes and they look much better designed to me... So if
anyone is interested please respond, and maybe they will hear and put some R&D
time into looking at the flow and flow restrictions on this intake, and comeout with
a New Chrome looking better flowing intake manifold .

Come on guys I know someone has this Idea going thru the head......Thanks

I think PTP mentioned some time ago that they were considering developing a new manifold. I'm sure it will be awhile though as they still haven't released their turbo kit.

If you want my opinion, and you did ask. You will be hard pressed to better the one you have. I have studied it in the course of designing a manifold for my supercharged application and see no great avenues for better flow. Not that you couldn't make it bigger but you will lose power below some point where you start to gain. There are no sharp turns like in the exhaust so you can't find anything there.

I love to toss stock stuff and build my own, but in this case my instinct is to leave it alone. I'm only changing it because I have to gain some real estate. Yet what I'm replacing it with is almost the same as far as it can be. I have free hand but I'm going with Mazda. It costs me no more to make it different and I'd love to say that I made it better.

Hell, id just like it if you had a metal intake of the same design. I dont think much need to be changed and i think mazda did a good job with their design but i just dont like the idea or look of a plastic manifold. Just make a metal intake of the same design and id buy it!

Hell, id just like it if you had a metal intake of the same design. I dont think much need to be changed and i think mazda did a good job with their design but i just dont like the idea or look of a plastic manifold. Just make a metal intake of the same design and id buy it!


Just buy my supercharger, it comes in the kit.

^^^
That's what a lot of us, like me, are waiting for!!!

Actually the plastic was probably designed to keep intake air temps down. Plastic is very good at desipating heat.

We might be making an intake manifold for turbo setups but we haven't decided for sure yet. Hopefully some time this year we will start having a little more free time to work on our projects.

Like this:

http://www.rx8club.com/showthread.php?t=58416

Just buy my supercharger, it comes in the kit. Oh yeah I remember you saying that. THat will be awsome! I cant wait till you get your little project done!

Like this:

http://www.rx8club.com/showthread.php?t=58416Ive seen that too. the price scares me though! lol

We thought about designing one too.The plastic intake is ok but we have seen it expand and contract with boost pressure.Watching your intake expand on the dyno is sort of scary and it is only a matter of time beffore the glue that holds it together lets go.Here is a picture on an intake we designed for the Z.

http://www.speedforceracing.com/images/products/infinity/g35/intakemanifold/g35_1_3.jpg

I am sure we could come up with something cool for the 8.



Tim

I want one of those!!!!! MAKE ONE LIKE THAT FOR THE 8!!!!!

Very cool, it looks like two giant hands with fingers reaching down into the engine.

The stock intake manifold is a much better design in every area than any previous manifold ever used on a rotary as supplied by Mazda. It is most certainly better than the 3rd gen RX-7 manifold. It's turns are very smooth and gentle. The plastic piece is very nice. Making a different one out of aluminum may be beneficial for strength reasons but don't expect to really improve on it in the power department. You could alter the tuning a little bit by varying it's collection length though.

Very cool, it looks like two giant hands with fingers reaching down into the engine.

You call that an engine? If it ain´t a rotary it ain´t an engine... :yelrotflm :smoker:

We thought about designing one too.The plastic intake is ok but we have seen it expand and contract with boost pressure.Watching your intake expand on the dyno is sort of scary and it is only a matter of time beffore the glue that holds it together lets go.Here is a picture on an intake we designed for the Z.

http://www.speedforceracing.com/images/products/infinity/g35/intakemanifold/g35_1_3.jpg

I am sure we could come up with something cool for the 8.



Tim


Thats awesome.

Hey guys thanks, I was unaware of some of the manifolds that are out there, or will be soon.

I don't know if any of them flow better, and Rotarygod I buy one if you make one for half the price as you said earlier....

Hey Nemesis8, Have you seen any new updates on the HKS Intake Manifold, I like that it has provisions for two additional injectors, will come in handy...

I will probably buy one to see if there is a better flow at the higher RPM's. If there is I thing
I will have solved my problem of the boost falling off a bit at those higher RPM's...

Anyways, you guys are Great, I love the communications we have .....I will do alittle more
research and talk to afew of the vendors you guys have posted about, and see what time frame of any New ones to hit the market... Thanks...

Actually the plastic was probably designed to keep intake air temps down. Plastic is very good at desipating heat.


This is sort of true, sort of not. Plastic will not get heat soaked as fast as aluminum, but once it does, it will stay hotter for longer. Metal will take heat in quickly, but will shed it just as fast.

I think I remember reading that Mazda choose plastic instead of aluminium mainly because of the weight of it. If you compare the intakemanifold on the FD3s compared to the 8, the new one is lighter.

No new knowledge on the HKS from me, but maybe Japan8 can chime in if he is reading this. Those pics were from a show in Tokyo

Well, I talked with the guys at Acosta today about their Intake Manifold for the RX8..

It takes them about 2-months to fab and ship.. They did say that on the Greddy turbo I would see more HP than what they show for a NA motor... So I'am given this some serious thinking, I just wish it was'nt so much (1,599.00). I would feel like taking the chance more
if it was around the $ 800.00- $ 900.00 range...

I also talked to afew other vendors, and one has said he feels that it's not the lack of flow of the intake that is dropping the boost at high RPM's.... He told me that other turbo and supercharger systems show a drop also and that they have other intake manifolds.

So I hope soon we will figure this out, I would still like the Intake Manifold for the fact of
1. Safety, because I heard that under boost some have seen the plastic intake expand
and this over time this can't be good...

2. It would be nice to see a polished intake under the hood.

3. If , like in the HKS setup have two new injector sites..

Also I'am hearing some rumors to hang on for afew weeks, that I can do. But after that I must try something... Thanks everyone...

Make your own decision on this as it is only my opinion but I don't see any intake manifold being worth $1599. Theirs isn't even an entire manifold. It's only an upper manifold.

I don't think it is the manifold causing the boost to drop as other turbo kits can hold boost fine. I think you could find a much better use of that money.

Hey rkostolni, please explain which turbo out there is holding full boost all the way to redline.
I have'nt seen one yet...

I dont think it has to do with the upper manifold, I think it has to do with the last runners opening.

Think of it this way. Boost dropping off isn't necessarily a bad thing. The turbo is more than likely pushing out the same amount of air. It's just that the engine is gulping a lot more than before because of higher rpms and the third intake transition.

Before the third transition, the engine isn't taking in as much air, so the air that the turbo is pushing out is backing up in the intake manifold (the computer reads as more boost though). Once it goes past the transition, the engine takes in more. Also this is good because the compressor is having to work less to push the same amount of air, reducing the amount of heat it dumps into the air. It's kind of a win-win.

Now I don't know if this is the case with the Greddy kit... But it makes sense to me...

The custom kit by Ozzy holds boost pretty well. Jeff claims his holds boost. The Bullseye upgraded turbo can supposidly hold boost, and I believe, although I'm not sure on this one, that the SFR turbo holds boost.

Hey rkostolni, just checked out SFR dyno, Power falls off after 7100rpm's I assume the boost is falling also... You say: "ozzy's holds boost pretty well" What's pretty well, either it holds boost or it dosen't..

I'am not being a (smart ass) just trying to see if it is true that nobody is holding steady boost after 7200RPM's.... for an RX8...

I don't think the power falling off is indicating the boost is falling off. You might want to call them and see. If I remember correctly, Ozzy's was running like 13psi, it does dip down some, but he is still able to hold 9+psi to redline.

From my experiments, the boost seems to fall-off due to the increased exhaust gas pressure cracking the wastegate when the tertiary runners open. Adjusting the wastegate let me hold about 2.5-3 psi more at redline. I go from 10psi to about 7.5-8psi.

Sounds like a good idea MadDog, I'll try it. Actually I remember Benny telling me to losen the adjustment at the beginning of my install last year because I had too much boost ..So I'll try tightening the adjustment to the orginal setting, then go from there.. I always have a record of what I've done before... Thanks..

Hey Rotarygod, on the (3rotor thread) you say the Renesis intake is much bigger than the 13B, where did you get this info or where can I see this info... If that's true can that be why boost falls off on the Renesis FI, because the turbos are not big enough to handle the massive intake size... I wonder if twin seq. turbos would help that or just a bigger Turbo, Hey what do you experts think...I
was still thinking of getting the Acosta Intake but I don't know now...

Let's see if I can help you guys. It wouldn't make a difference if the intake manifold were as big as a fuel dragster. When it is full, that's it. If the engine is so big that it sucks more air out then the turbo puts in then pressure will go down.
If the turbo puts out more air then the engine takes at X pressure then the waste gate opens.

Now in the instant case I believe that some have gotten pressure up top with these kits. However if you are going way out of the efficient operating range you will gain nothing but trouble. There may not be anything to gain going away from the original design point. Some engineer matched that blower to where he was aiming with his design. If you guys think you are smarter then he is, then by all means modify the shit out of it.

You might look to see it the TB is closing off from some input it is getting. Not sure that works that way, you might want to ask MM.

Too bad someone like Greddy, SFR, Mazsport,RP,Pettit etc, don't have the time or interest to buy a Renesis Motor so they can work on it in a dyno room and really see what's going on , on this motor.. I would believe it would be so much easier to see what,where and why we are having problems with boost falling off.

This way we can see if it's the Intake, Intake Ports, The Exhaust, the Exhaust ports, The Turbo or whatever.... that way we would know what to fix and what to spend our money on. Ah well someone will figure it out eventually...