Hi I have a 90 GXL and want to install a better intake. So far i have just realized the problem with the air flow meter. I was wondering if any of you guys could show me what you did to upgrade your intake system. Thanks

 

The S5 intake is pretty good.
Maybe check the "for sale" forums for a replacement.

The next step up is a stand-alone ECU that uses MAP & TPS senors for fuel mapping.

 

i wanted to shorten my intake piping but my stick welder cant weld alluminum im thinking of just cutting and changing things with the stock s4 manifold to shorten and straighten it. then i will borrow a mig welder from sumone.

 

why dont you just rig up a itb setup? it can be done with the stock ecu. anyone that says it cant is stupid.

 

Any welding shop should be able to get you aluminium rods to use with your stick welder. You'll need at least 120A to get enough heat to the metal, and it takes some serious practice.

 

really??? i always thought it would be impossible to weld alluminum with my stick welder. that would be great if i could! ill have to look in to this....

 

The weld quality is not great, but it does work. With practice, you can get quite good at it.

Edit...I even found some aluminium flux cored wire that I can't wait to try out. Might be prone to jamming, though.

 

the flux wire is for a mig welder right? i think the weld quality would be better with a mig and i might be able to get access to one.

 

Read the part right under turbo's, mazda spent a lot of time/effort on making the intake systems for our cars,i doubt any of us has the thousands of dolars to r&d a proper intake system the will test better then mazda's

 

better is in the eye of the beholder. mazda designed it for a wide variety of people. if a custom one can be made that the owner is happier with, then why not?

second, i think this is getting off topic. when he says intake i bet he means everything before the throttle body. this can be replaced with aluminum piping. i've never seen a kit for it but i've seen it done but don't know the size off hand. the plastic elbow at the throttle body must be retained as well. as for the maf, mazdaspeed7 on this site was designing a system that uses a much better flowing hot wire type maf out of a mustang. check out this thread for details. i don't know how successful it was though.

https://www.rx7club.com/showthread.p...ht=beefy+n%2Fa

if you are thinkin custom manifold, the only ones i've seen are designed for individual throttle bodies or carbs. however if you are worried about flow in the manifold, this thread entails some ideas on porting it.

https://www.rx7club.com/2nd-gen-archive-72/porting-intake-manifolds-how-reactions-79511/

 

it's 3inch used with adapters, get a kit from a honda or anything and chop it up.
I have done it on the s4 with the afm, the s5 with the mass air flow sensor and the 84-85 se systems. rx7doctor

 

The flux cored wire is for a standard flux wire welder. Some MIG welders allow you to run gassless (flux wire). No, I doubt the weld quality will be great, but it will work.

I ran some aluminium rods last night. They burn FAST, and you need to crank the current (aluminium takes heat away from the bead very quickly). I can't imagine using them on any kind of thin aluminium without great deals of practice. Have not tried the flux cored wire yet.

 

One more thing about the aluminium stick electrodes. You need a DC welder, and you have to run reverse polarity. AC just makes a mess.

Flux cored ALU wire is junk without a spool gun. It just makes a birdsnest in regular wire feed welders.

 

CAN it be done? Yes. That gets rid of the potential for being called stupid as per the above requirement. The stupid part is actually in thinking that this will work properly and that you will actually be faster with it. You won't. Changing the ecu but using the stock manifold will be faster than using the stock ecu but changing the manifold. Anyone debating this has absolutely no experience with modding these cars "properly".

If a better intake (not intake manifold) is wanted in this situation, don't shorten it. It won't do any good. The best thing to do is to get the air source from out of the engine bay. If a better intake manifold is wanted, get a system that allows you to dump the factory ecu first. You'll go faster this way. The stock air flow meter has less than 5 sq inches of airflow potential and even this miniscule area is blocked with a spring loaded flap door. This is even true in the S5 except that the door is now a cone shape. Standalone ecu's don't have to be expensive (as little as $150) nor are they complicated. My car started up on the very first try with one. All the time I had spent in the past trying out different manifolds and mods to them while retaining the stock ecu were just wasted time. Nothing did anything of any real benefit and more things than not actually hurt performance. Getting rid of the afm was the single best thing to ever have been done to the car and now I can do anythig I want and tune it properly. Proper (not bandaid like S-AFC devices) tuning is everything. All else is an excuse for doing it wrong and excuses aren't results.

 

if you are thinking about modifying what comes after the thottle body in any significat way, you do not want to build your own intake manifold without a way to flow test it etc. your AFM reads the total air coming in, if you have some flow characteristics where you end up with an uneven split of the air between the rotors then the fuel mapping would be messed up for each of them. this will lead to lean conditions in one rotor and rich in the other and that will not make for a happy engine. to build your own intake manifold, besides something simple like a short individual throttle body setup, would most likely be a wasted effort. you will be getting into the type of project that race teams take on, except they have the funding to test their setups and to cope with the failures.