Hey guys im building my dream car a mazda 1986.
I love the intake manafold of the series 6 1992 and onwards i was wondering if i could keep the block and just fit the seriers 6 manafold? Or would i have to source a hole series 6 block and put it im my 1986?

 

Your '86 will have a 6 port N/A engine and the S6 manifold is made for a 4 port. Aside from other issues the ports won't line up with your motor.

 

he never said his was an NA...
so IF your car is an NA (non-turbo motor)
you can't, just as Craiger said.

but IF its a turbo engine that you have, you can do it with a spacer(about $150) that someone sells (forget who, sorry)

plus the cost of the FD intakes/throttle body (usually sell for around $200 IIRC)

 

He did however say it was an '86, and all '86's were N/A (in North America). If he has done a motor swap than that would be some very important information which he should have included.

Even if he has a turbo swap completed, he will need a way to hook up the S4 TPS, and find a way to drive the S4 OMP. Unless he wants to get a standalone and premix. I have a feeling if this were the case the question would not have been asked in the first place.

Back to the original poster. Anything is possible with enough work and custom fabrication. Also note, an S6 block IS NOT by any means a drop in to an S4. If nothing else, the motor mounts are in completly different places. When swapping engines it is generally recomended to stay within series. It will make your life a lot easier in the long run.

 

Not in Japan which is where i'm guessing his car came from.

 

You beat me to my own mistake. I corrected my former post.

 

If it is a Turbo II you can use the S6 upper manifold by bolting it to the S4 lower manifold. You will have to do a little bit of grinding to match up the ports and redrill 2 holes but it can be made to work. You don't need a spacer but can use one if you find one. The S6 lower will not work on an S4 engine. The intake ports on the S6 enter the engine from higher up as opposed to the S4 that has the intake ports coming in directly from the side. Don't even try to adapt these. It'll be crap even if it is made to fit.

If you have a naturally aspirated car, you can again use the upper manifold from the S6 and the lower from the S4. However since the non turbo cars had 3 piece manifolds you'll need to fab up a center section that will adapt these 2 parts together. It'll need to be several inches long but with relatively straight runners. If this is what you are trying to do, hold the S6 upper over the S4 lower in the car and measure the distance between them. Then fab up an adapter. You'll also need to install injector bungs in this section as well as a custom fuel rail.

Another problem you'll have is that with the larger throttlebody of the S6, you'll need to also install a new ecu in the car that you can program. I'm not going to say that it is impossible to make the larger throttlebody work on a stock ecu. However even if it did, it would be far from optimal and probably down on power and drivability as a whole. If you are looking for simplicity this isn't it.

 

S'all good. Rotary trivia FTW.

 

So a couple extra s6 parts and a standalone would do it for us TII owners.

 

What's the real benefit from this? Because I can't really see one.

 

It looks cool. That is all.

And on some modded cars it has produced a slight shift in the power band.

 

Thanks for your replies guys I'm new on here you all replied very quickly.

To answer some questions I'm looking for a series 4 1986 haven't bought yet.
It will be turbo and I'm going to pretty much start rebuilding it as soon as she arrives in my driveway.
I owned one a couple of years ago and have throughly missed it since so I'm looking for one now and this time ill never sell it again (dam wife) lol...

So any way I'm pretty much gonna build a show car and i hate the look of the standard top mount inter cooler and when you add a front mount your left with an ugly manifold starring at you.
Ive always loved the look of the series 6 manifold when polished it comes up great. Even the Cosmo manifold is more attractive.

Any way I'm sure ill work it out ill probably keep the series 4 engine rebuild it and do some custom mods and fit a series 6 manifold or a Cosmo one or even get something made specially. I just love that part of the engine bay its kinda the center piece to me its the part of the engine bay I'm most attracted to.

By the way my technical understanding of rotaries is very limited hence joining a forum to learn. A few months in here and I'm sure i will be ready to start building.

 

if you're gonna do all that work, why not just get a series 6 motor and drop it in? The custom mounts will cost about the same as all the foolishness required to swap the manifold and you'll have a better motor.

 

In order to put the S6 upper intake manifold on a S4 TII you must use the S5 lower intake manifold as the bolt pattern where the UIM bolts to LIM is much closer and can work with some minor machining.

 

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/what-makes-fd-intake-manifold-better-than-t2s-714929/

I had a thread about this (advantages of the s6 manifold)

 

I'm gonna agree with you on that one.

 

Looks like a peak of over 20 ft/lbs of torque and about 20 RWHP gain in a broad region between 4,500rpm and 6,500rpm and a smaller ~9 ft/lb and RWHP peak bump between 3,800rpm and 4,500rpm while only losing ~2ft/lb and HP in three very short sections below 3,500rpm on a ~360RWHP 13B.....

Read this thread
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/conclusive-b2b-dyno-tests-fd-uim-fc-uim-655708/

For comparison, when Dsport did a Lancer Evolution intake manifold shoot out even the very best $2,200 manifold only gained ~40hp from 7,000rpm to 7,800rpm, ~20hp at 6,000rpm and lost power (as much as 40hp) at any rpm below 6,000rpm on a ~650rwhp engine.

Hmm, Lan Evo owners have to pay $2,200 for a max 7% increase in power over a short 800rpm with as much as 18% loss in a 1,000rpm band and RX-7 owners discount almost free 6% power increase. Wonder why the rotary engine is so under developed :P

 

Oh, and it looks cool, which is reason enough to do it :P.

Here is a pic of my set up.

 

Thats cool...

Fantastic work looks great and looks like you got some power gain as well.

well done.

So how much did it cost you roughly? and sorry what throttle body are you using?

would love to hear a step by step guide to how u achived this if its not to much trouble chears.