Hey guys,

I'm relatively new to FD's and their stock operating system. I am by no means new to 7s or rotaries, in fact I'm a successful rotary rebuilder. I have worked on a few FD's here and there, ranging from stock to 400hp single turbo. I do 95% of my work on 2nd gens, which I can safely claim to know almost everything about in stock form. However I have never really done much research into FD's in stock or lightly modified form, such as what components perform what functions, failure symptoms, etc. All teh FD work I have done has been straight remove and reinstall with no modification.

Anyway, I finally found a good deal on a dead FD for my own project. I just finished up my 89 turbo convertible project so I wanted a new toy. I got a 93 touring with 107k, all original, blown engine, already partially disassembled. Today, I pulled the rest of it out, and later this week I will be disassembling it for rebuild.

My questions regard the engine peripherals. Such as that big *** vacuum rack with solenoids, and the non-seq. mod.

Now Im no forum newbie either, I know to search before even thinking about asking the same **** you guys have already answered. After about 2 weeks of searching, I have found a lot of info about non-seq. setups. However, I wasnt able to find much info regarding my main question. What all can you leave off of these, with the *stock ecu*, without causing problems? For example: I would like to leave out the vacuum rack and solenoids, remove the actuators and doors in the turbo system, run non-seq., with no emissions controls on the engine (acv eliminated, air pump, etc.).

The only good info I found suggested either leaving the solenoids plugged in but not connected to vacuum (defeats the purpose of my mod, simplification and cosmetic cleanup) or wiring in resistors (330 ohm, wattage I was not clear on) to each plug to fool the ecu. What happens if you leave all those solenoids disconnected totally (other than the functions they control not working anymore)? Im sure the ecu throws codes, right?

IF the ecu throws codes, are they 1) the kind that only show up when codes are pulled manually, or 2) the kind that trigger the check engine light at all times?

I'm stuck between either just putting it all back bone stock for a while (provided everything turns out to be reuseable, such as stock twins, solenoids, etc.), or going bare block, single turbo, and straight exhaust. IF I do the first, I can have the car on the road in a couple of weeks for just a few hundred bucks. If I do the second, it will be a winter-long project and cost several thousand dollars. I dont mind putting money into a car, but I like to do it over time, so I can work out any bugs first.

I'd like to get some advice from the experienced guys here. To recap: can I leave everything off the engine, run stock twins nonseq. and the engine with no emissions while retaining the stock ecu? IF so, what codes will the ecu throw, and do they result in a constant check engine light? If so, is there a way to avoid this?

I bet most of you are going to tell me to ditch the stock ecu. From what I can tell, the ecu is the first upgrade necessary to an FD. I know I need to search more, but what are the sub-$1000 ecu choices and what would be suitable for my use given the above terms?

My eventual goals for the car are single turbo with FMIC, bare block, ecu, fuel pump and injectors, around 300-350hp. For now, I can live with near stock, so long as it is reliable and smooth.

 

Welcome to the third gen section

As far as I know, if things like the air-pump are removed, and resistors aren't wired in place, the ECU will illuminate the check engine light. I think it's a constant on, and then you can pull the code to get it to do the blinky thing.

But if you want to remove emission control stuff, why not just wire in the resistor? It won't look much worse than having nothing there at all, and you won't have to deal with the annoying CEL.


Theres the kicker. Stock ECU. As you've found out
already from searching, the stock ECU is just plain horrible once you start modding the car. There are less expensive options than the Power FC, Haltech, and AEM though. For instance M2 has a few stages of ECU depending on your mods, and used ones can be had for ~$500. Pettit has similar ECU mods for about the same price. The only problem I can see with getting a non-tunable ECU is the non-seq. The stock ECU and any upgraded ones are expecting your turbos to be sequential, and expecting a dip in boost at 4500 rpm. If the dip isn't there, the motor runs lean for a split second. I blew my motor, according to Dave at KDR, by running the stock ECU with non-seq twins.

That being said, many people have successfully run the stock ECU, and upgraded ones with non-seq turbos, but my engine went POP, so it does happen.

Your goal of 300-350rwhp is more than attainable on twins, and the low end of that is attainable on stock twins. There is a lot of work involved in going single, so I'd suggest taking a look at upgraded turbos from BNR, M2, or some place like that before making a decision. Unless you want the clean single turbo look, which no twins can provide.

Good luck!

 

300-350? 300 is about where you'll be with a stock motor, stock twins, stock ecu and all the bolt ons at 10psi if i am not getting mixed up. There are people with around or over 400hp on stock twins.

single is a much nicer, cleaner, and more reliable setup once it is tuned and kept at a reasonable boost (which at 300-350hp, thats not a problem). i'd love to do a winter project like you have in mind, but for now my stock twins, stock motor, and stock ecu are plenty.

 

So stock ecu and non-seq. are not adviseable together. What about taking out emissions related stuff and leaving the boost control solenoids/hoses? ****...I need to find a good diagram of the solenoids and hoses...is there an online FSM for the 3gen, or a good diagram floating around somewhere?

 

http://www.scuderiaciriani.com/rx7/v...placement.html

 

Great link, thanks. At very least that will allow me to put it back stock if I so choose...someone has already broken and/or ripped apart half the stuff on the engine, so it'll be harder to sort out than it normally would be on a straight remove and reinstall.

Anybody wanna clue me in on which parts of the system are turbo control and which parts are emissions controls that can be removed and resistors put in their place?

 

IS that a fact?? ISnt the engine 245hp stock @10-8-10 stock boost configuration? IF so, how do you then get 300hp @10psi on stock twins??

 

Well, I got the engine torn down today. IT was a victim of carbon lock. SEVERE carbon lock. The worst I have ever seen in a rotary, as in 100+ cores disassembled. At the apex tips there was literally 1/8" of carbon. The thing must have been allowed to sit a while or something.

GOod news, everything is reuseable. Rotorhousings are about an 8 out of 10, irons look very good with no coolant seal jacket cracks, rotors should be reuseable unless some of the stuck seals dont come out.

At this point Im probably gonna put it back stock for a while, do the engine breakin and drive it, and then in the spring do the mods all at once. I have a lot of broken solenoids and check valves to replace. Thanks for the assistance guys.

After I get it together and running again, and get the car painted, I will likely post a few pics.