WA-GONE09

So how finiky are the motors and tuning on the FD platform. I've currently got an opensource tuned STI and the motors in those are very tempermental to changes so I'm used to dealing with tuning and adjusting for every change in climate/mod to be on the safe side. I know the rotary/wankle motor has its issues but are we talking one of the first things to do is to get rid of the cats and perform a good baseline tune?

also ive read something about 2 stroke oil mixing with the gas? can anyone explain that a little more. I understand that the motors eat a ton of oil compared to other cars but is there a specific reason to use 2 stroke oil and are there any mods that need to be done motor wise to perform this?

thanks guys, sorry for the questions, I'm just new to the world of 3 sides vs flat horizontally opposed pistons.

Sgtblue

iTrader: (16)

Buying a Used RX-7
http://www.marx7.org/infocenter/faqs/3rd_faq_main.html
Buying a Used RX-7
Buy a Used RX-7
1994 RX-7 Consumer Reviews | Fast, affordable, exotic beast | Epinions.com

^From the 3rd Generation section FAQ sticky.

The rotary doesn't "eat a ton of oil". On a stock system, the oil metering pump (OMP) injects a fine mist of engine oil in the intake phase of the engine. Unlike piston rings, hard seals on a rotary can't be lubricated from one side. The injected oil reduces wear and aids sealing/compression. Can't remember exact amounts that are used this way, but you probably won't notice the loss between oil changes. Some delete this system and "pre-mix", which is simply adding 2 cycle oil with fuel at the pumps...and there are other options for those into modding things as you apparently are.

KansasTom

I do the premix and leave the OMP intact. Keep them cool and lubricated and no problems

WA-GONE09

Thanks Sgtblue for the info and KansasTom about the opinion. I guess it makes since since shooting conventional engine oil into the motor could leave more of a residue inside of the housing and motor vs 2-stroke would burn cleaner and reduce deposit.

thanks guys for the info

Sgtblue

iTrader: (16)

OP: I happen to do the same (premix at a reduced rate and keep the stock OMP) and hold the opinion that (on a standalone computer) neither the stock OMP nor pre-mixing are ideal by themselves. I also have an auxillary injection system in place that should keep carbon down along with it's other benefits. BUT also know that this is MY opinion for MY car. Some other really smart people here might feel different, especially when it comes to their car. Point is, if you end up buying an FD, study and learn about the car yourself and don't take any one person's opinion for gospel.

Right. And of course this could also apply to anything from piston engine to a hot-flashing menapausal prostitute.

Cruzzer38

This forum is just great lol. Sgtblue you sir are the man

misterstyx69

iTrader: (142)

Yep..gotta keep the Skank engine cool..or it over heats..won't accept the Input shaft and will expel hot gases out the rear.
Major arterial damage can result and affect every day driving!
This can result in Excessive wear and higher prices at the Pimp!

gerald m

Use Goose Grease on the input shaft Dave it works great although after a bit when the goose grease gets warm it does tend to quack a little .

diabolical1

iTrader: (3)

FD. Lubrication. Black Holes. okay, got it. thanks guys.

mitim3

iTrader: (1)

I think pre mix is often talked about as a precaution or backup for the oil injectors. Sometimes the oil injectors don't squirt enough oil and so the premix is there for lubrication/sealing etc. I know edemitsu carries premix as well as pettit racing (protek R: Protek-R 1-gallon Jug)

dvaz

Pettit racing gives a good explanation on the whole premix thing, might wanna check their website out.

Sgtblue

iTrader: (16)

Yes, IIRC it's mixed in with a plug for their stupidly expensive magic rotary oil.

FDrx7guy

I also premix and use the omp and it's standard rate, no issues, does stick a bit though

Evil Aviator

The FD is a little finicky because it uses a speed-density engine management system that does not compensate for changes in volumetric efficiency. It is also an older system that will not work with your OBDII whiz box, so any serious modifications will require a standalone EMS and an experienced rotary engine tuner. Those who try to cheap-out and tune via what they hear on the internet tend to blow their engines quite often.

Personally, I don't see the urgency in screwing with something that has been running just fine for 20 years, especially if you are a noob. Rather than randomly throwing money and parts at it, how about driving it as-is for a while, and maybe taking it to an experienced rotary mechanic for a check-up? Yes, I know, it's a radical concept, but I'm a real "outside the box" kind of guy. (The box is full of broke guys with blown engines).

Most of this has been covered already. I tend to support leaving street cars with the original oil metering pump. The engine typically lasts 100-150K miles before a rebuild is necessary, sometimes as long as 200K. I have seen no legitimate study proving that premixing makes a street car engine last any longer, nor have I seen any extended warranties for premixing offered by any of the engine shops. Given that, I don't see anything wrong with premixing on a street car other than the fact that additional oil will lower the octane rating of the fuel.

In original form, an RX-7 typically consumes about 1 qt per 3,000 miles. This is not a ton of oil.

I live in the world of rotary, vee, flat, centrifugal, and axial-flow engines. I'm dying to get my hands on a dynacam engine, but at this point it looks like I will die of old age before an affordable production version is available. For that matter, I may not even live to see the 16X engine in production, lol.

WA-GONE09

haha thanks for all the comments ( especially the lubrication ones lol) and thanks Evil Aviator, I understand what you mean by leave stuff alone and enjoy the drive and the old school tuning that would be needed lol. I don't plan on doing anything for a while, but I know that the mod bug will come at one point so I wanted to test the waters and gather some info regarding things.... btw hi from across the state.

Sarios2

I find it very strange to put an oil gas mixture in the tank unless you go for hugh power. I am sure that Mazda calculated the lubricatrion good enough to keep the engine running.

Sgtblue

iTrader: (16)

^A (valid) criticism to MAZDA'S OMP system was that it injects oil from the crank case. Crankcase, or sump oil is not designed to burn cleanly and will by nature, already contain contaminants. That tends to increase carbon deposits in the combustion chamber surfaces and that's always been an issue for the rotary.
The OMP system was almost certainly designed so that the average "non-car-guy" owner just didn't have to worry about pre-mixing, or maintaining the level on a separate supply tank of oil for the OMP system.
So pre-mixing two-cycle oil, which burns much cleaner and hasn't been contaminated makes some sense...and shouldn't be so strange. As mentioned above, IMO neither system is ideal...at least when you move to a standalone computer, but that's a whole separate discussion.

vicious1

1. FD's are expensive
2. Premixing is for road course pro racing
3. Don't use synthetic oil

Sgtblue

iTrader: (16)

Yes if you buy wrong, mod poorly or can't read and follow FSM. I'm not wealthy.
Wrong. Perfectly acceptable even on a streeted car.
If you don't want to, fine. But many owners have for many years without issue. Yes, I'm well aware of what MAZDA said. No, I won't debate it further. There are hundreds of related threads already...go read some.