Ok.. First off, hi.. Im Josh.. I am about to get an 89 rx7 non turbo.. I have been into cars for a while now, and am very good at piston driven motors, but I wanted something different.. So I am here..

My question is, if I get this car, I plan on keeping it N/A for a while, as the turbo swap will cost grip.. lol.. after intake, headers, exhaust, motor mounts, what else can I do?

I see alot of people in here talking about porting and whatnot.. What are they porting? What about the cam (or lack thereof)? Is there one, and if not, how do you get the valves to open wider?

Im just curious what I should do after the basic I/H/E.. What makes all motor power in these motors? Could someone tell me, or give me some links?

 

wow you have alot to learn. but ill help because i remember being in your same spot.

first do some searching. all your questions can be answered and have been answered in the past.

porting the motor does not involve cams because there are none on a rotary. the best way to get more power out of a rotary is to port it and then do the supporting mods bigger injectors, ECU..etc

i do suggest you keep it NA for a while untill you become very familiar with the rotary and then look at swapping.

alot can also be learned through searching around google.

 

After the basic mods you could get an aftermarket engine management system or a chip like the RTEK 2.0 and tune the fuel maps, timing, VDI activation, etc. The porting is referring to the intake and exhaust ports in the rotor housings. Go to howstuffworks.com to learn about the rotary engine. Or rotaryengineillustrated.com. Your best bet in increasing hp and tq in a naturally aspirated engine though is going to be increasing displacement.

 

I have done some searching, and just have not found anything satisfactory.. and I am not a rook.. lol.. I am very familiar with an internal combustion engine and forced induction (had 2 awd turbocharged DSM's, and a few fast honda's)...

So, what are the normal things to start porting and what the general power gain from it (after I/H/E have been done).. Start with the TB and work back? or from the the IM and move to the TB? Im just curious, because after I get it and give it a tune up, I want to start modding it..

What are some general numbers of power gain from these port jobs?

sorry for so many questions.. last one.. How high can a rotary rev? Whats the normal powerband in these motors?

 

Hehehe. thats funny

but really. i've been in your same position. Once you buy this car, your best friend is going to be this website, the FAQ section, the stickied threads and your trusty haynes manual.

dont get boned. make sure the car runs and drives nice b4 u buy it. (my 1st rotary mistake.) and if you can, reasearch on how to to a compression test on a rotary and do that to the 89 b4 its yours.

But as long as u take care of it, it will take care of you. buying an rx7 is always worth it.

 

o yeah.. and I dont want too much.. Because I will most likely swap to the turbo'd engine.. Whats a reasonable amount of power to make off of bolt-ons, and porting the IM and TB? Is it possible to be into the 14's with bolt-ons and a tune?

Sorry for being such a newguy-type..

 

for sure.. I am actually quite active on DSMtuners.com, honda-tech.com, focusfanatics.com, and jbody.org... Im very happy with the support I get in forums, and I like helping others in the forums as well with problems.. Especially on DSMtuners..

 

rotaryengineillustrated.com

^^ that site is tight.. I will be reading that... lol

 

Replacement of the airbox and headers with a free exhaust will make the biggest difference without opening the motor.

Any port work will require a rebuild of the motor.
There are no valves, cams, lifters, rods, rings, chains, tappets or rockers in a rotary.

Aside from exhaust the only way to make big power gains is with porting or boost. The bigger the ports in general the more power you will make. It will also start shifting the power higher up the RPM range, reducing idle ability and longevity of the engine.

 

Weight loss.
I have witnessed an 88 RX-7 run mid 14's on an original factory engine with nothing more than a cone filter and headers.

However it had no interior (no dash), no power anything, no headlights, no passenger seat and a lexan windshield. Probably weighed 2200lbs.

 

haha.. I dont want to gut it.. what kind of power does just IHE make?

If I buy a clutch and flywheel (ACT) for the NA, will it bolt up to the turbo'd motor and tranny?

Im actually reading about the different ports right now.. Im wondering how easy it would be to rebuild one of these motors, considering the internals are nil compared to a regular overhead cam engine, and those are easy..

 

Good rule of thumb, staying N/A and streetable - you'll be limited to 200whp and less.

Anymore then that - go turbo.

 

If you buy a clutch/flywheel combo for an NA it will not fit the turbo application. And if you are buying a lightweight flywheel keep in mind you will have to buy a rear counterweight from an automatic car of the same series.

Rebuilding a rotary isnt that hard, but its all the time involved in cleaning everything and checking to make sure every part you intend to reuse is within mazda's spec's. And then its a matter of putting it back together without damaging any of the coolant seals in the process. There is more detailed information in the various subsections of this site, and AtkinsRotary and a few other engine builders also sell detailed video's showing the process of rebuilding a rotary engine.

As far as porting goes theres only so much material in certain area's you can remove before youve ported too far and have to junk the iron or housing.

 

The flywheel for the N/A is a different size from the turbo flywheel. I think it's something like 2 cm.

You might want to check out the n/a performance section as well

https://www.rx7club.com/naturally-aspirated-performance-forum-220/

As for the mods you spoke of, the throttle body mod won't do much, if anything, on an n/a outside of making the throttle response a little crisper. I've owned a both a car with it, and without it, and have not noticed much difference. If you want to take the time to do it then that's up to you.

Since you are planning on making it faster you might want to consider upgrading the brake's to the 4-piston calipers from the Turbo II or GXL. You can usually find the pair in a junkyard for about $60-70.

 

I say you ask too many questions. I'll give you this gift.
https://www.rx7club.com/showthread.p...ighlight=beefy

 

Thats fine.. I will do in and out, and all the mods that I can, then just swap to a turbo'd motor.. 180-200 is fine for right now.. as long as it gets me around... Ill just gauge it up, drop it, tune it.. Ya know.. make it purrty

 

yeah.. upgrading to all the turboII stuff over the next year would be my goal.. well, not all of it.. really, the brakes, engine, etc...

Rebuilding any engine takes the same.. gotta be clean and measure everything.. So that doesnt scare me..

 

http://www.rotaryengineillustrated.com/ Click on every link, great annimations on how the rotary works.

yawpower.com , read through ALL the tech articles.

And thats a good start.

Now go get your learn on...........

~Mike....................

 

Oil pump chain.


HE SHOOTS HE SCORES

 

stick with the stock airbox and put a K&N replacement filter, unless you can make a shield for the cone filter.... you'll be sucking up much more and much warmer air.

 

+1 You ever feel those intake manifolds after a jaunt to the corner store? They be hot.

 

Bolt-Ons: High flow catalytic converter, mufflers. Bonez and Racing Beat are popular for good reason. Also check out www.aaroncake.net to make sure your 5th and 6th ports (auxillary ports) are still working. There are a couple other minor things like the cone + cold-air box mentioned, but those 3 are the big items. A lot of people swear by headers, but I haven't seen good verifiable numbers for a rotary. Racing Beat outright recommends against it if you keep the fuel injection, and they sell a good header (which they recommend if you get a carb). At the same time they sell a piston engine header for the Miata that does make power. That and the fact that the cheap brands are the ones making the high power claims should tell you something.

Tuning: SAFC, rtek, or a stand-alone ECU. Overly-aggressive tuning could instantly blow your motor without much warning and not necessarily right away. So you gotta be careful here.

Engine: If you open up and rebuild the engine (~$3k) you can get a street port while you're at it. You can get more from a bridgeport but most people don't because, among other reasons, it's a huge hit to mpg and emissions. There are no cams or valves in a rotary. A larger port is the rough equivalent of getting the valves to open wider and longer. The auxillary ports, which activate to add port area only at higher rpms, are the rough equivalent of VTEC.

Turbo: The best option is usually to swap in an entire turbo motor or just start with a turbo car. The $1.5k JDM swaps often need a rebuild shortly after installation. Putting a turbo on an NA is typically harder and more expensive.

All of the above are significant. Search the forums for more info.

 

Air flow makes power.... The ability to manage the power properly is an equal side of the equation. Larger ports does not necessarily make more power... check out the venturi effect.

Port velocity will overide port volume for making power. Charge temperature & density would impact net power as well. there are many factors that contribute to power. Port timing is critical.

It all adds up. Back pressure plays a role as well. There is no bolt on thing that does everything properly. whatever properly is. Ignition timing & split timing & plug selection and spacing also have impacts on performance.

Obi-wan was wise in hiding the truth!! only the chosen can find the true path of the force!! LOL

Ramses666

 

^ Wth? Venturi effect unrelated, higher velocity always robs power (but IIRC you need a high velocity at the auxillary port pickup tube to trigger the aux ports), charge temp & density cannot adjusted directly (no one pays or needs to pay attention to it), back pressure is always bad. I think those are all rumors.

Port size & timing (falls under porting), & ignition timing (falls under tuning) do matter. Just look it up when you're getting those things. Try a forum search.

 

[QUOTE=DJYoshaBYD;8189829]Is there one, and if not, how do you get the valves to open wider?[QUOTE]

............0 boy!