Stevey629

I know many of these questions have been asked before, but I would rather have newer responses and experiences, all in one thread. Your understanding merits a sincere appreciation for answers. And by all means, if I left something out with this, add on! I know I will be.

First off, a little background on what I am going to ask questions about:
I am getting my car back very soon. After being down since january, I have finally gotten around to fixing it, with a stage 2 streeport. The motor got tired and finally blew out on me at around 90k. I am going to be running completely stock otherwise, turbos and all (aside from a drop in K&N filter).

My first question regards the ever so fickle fuel managment. I have heard phenomenal things about the Power FC and its amazing capability and potential in the hands of experienced tuners. However, this bank breaking computer managment is an additional expense to the motor that I simply can't afford at this point with the rebuild taxing fort knox as it is. Are there any other alternatives? Or a soul out there that will sell one to me for less than 4 digits? I know the question is rather vague and open ended, but I am going to be running stock for quite a while, and from what my rebuilder said, I dont need fuel managment at all, but once I open up the exhaust in any way, Im gonna need either a PFC or something else with that port. I had my fuel injectors sent to RC engineering to be cleaned and refurbished, and I am planning on upgrading the fuel pump as additional saftey for the newly ported airflow duties.


ok, now that the first question has been addressed, the second one is concerning a DownPipe. can I put a DP on without the risk of running lean? I mean, don't get me wrong, I am not intending to push the limits of how lean I can get the motor before it blows up on me, but is a DP still within the saftey margin granted the fuel delivery (again, upgraded fuel pump and cleaned STOCK injectors) that I will have? I have read that a DP can really help a stock motor out, heatwise, and most importantly to me especially with this new motor...reliability-wise. I'm torn with what I should do here. But with a port, I may run over 10 lbs of boost, resulting in a woefully inadequate fuel system, equating to a waste of time and money, of which I have neither at this point.

3rd question: My exhaust compressor housing had/has? a crack in it. From what I have read, nearly all of them do this, but mine is still within the gasket line. I have tried asking about getting it fixed, but havent had a response yet from my rebuilder. What do you recommend doing in a situation such as this? Replace? Fix? Upgrade to single?
The turbos were rebuilt about no more than 300 mi. before the motor went on me. The only problem is that the housings were not replaced. "ack" is right.

and lastly, any other things that you would recommend as rebuild tips when putting the motor back in would be helpful as well. I am replacing the radiator with one from PWR, and I am replacing the Y-pipe and all intake couplings with beefier units.

maxpesce

On the turbos Living with the crack or finding a used set with a smaller crack are about the only real options - Cast Iron is really hard to weld w/o introducing new stresses in the casting leading to more cracking down the road. MAZDA will only sell the housings as part of a complete new turbo set for around $2500. The up side to buying new is that you can order the newer spec turbos that spool faster and are more efficient, especially the 99+ RZ spec ones w/ the abraidable compressor seals.

adam c

iTrader: (2)

I think a downpipe is a good idea. A streetported motor needs to breath, even more so than a stock motor. With a stock ECU, you should install a boost controller when you do the downpipe. Since you are on a tight budget, do the HD boost controller. Nothing gets cheaper than that. Here's the link:

http://www.rx7turboturbo.com/robrobi...controller.htm

If you are looking for an inexpensive intake upgrade, here is another link:

https://www.rx7club.com/forum/showth...hreadid=121491

Your manual boost controller will allow you to upgrade while keeping your boost levels from going beyond the limits of the stock ECU.

alberto_mg

Don't take this the wrong way, but why are you even bothering to port the motor if you intend on keeping you car stock or very close to stock?

It just doesn't make sense. Usually you port the motor to make more power by enabling the motor to flow more air, but you seem satisfied with the stock performance so why bother? By flowing more air, it would follow that you very likely might need to flow more fuel.

In my opinion, it would seem more logical for you to pass on the porting and spend your hard earned cash on better silicon type water/oil seals which will withstand heat better and install a downpipe for the same reason. This would work very well with the stock computer.

While I personally don't know for sure, I would hypothesize that the port might not work very well with the factory computer due to the fact that more air is flowing through.

The Y pipe is a great idea and so is the radiator but what are "beefier intake couplings"?

IMO, it just seems to me that you would be better off not doing a port.

Stevey629

Alberto, ur right. Keeping it stock doesnt make sense. However, since the motor was apart, I might as well have taken the liberty of getting it ported, setting it up for future performance modifications later. So I did so, with the hopes that until I can manage to save up more cash I can run "stock" for a while without worrying about fuel. In response to the boost concern, as long as I keep the boost under 10 PSI, Im clear correct? In any event, thx for the suggestions guys.

911GT2

You *should* be safe at 10 psi, as long as you're stock. Dave at KDR told me this, and I specifically asked "even with the streetport" and he still said yes. But as soon as you start opening things up you will need the ECU.

I understand your concern about the PFC and it's price, as I'm having the same dilemna. But if you plan on modding your car in the future to the point where it will be necessary, then you have two options.

• Buy a non-standalone, like the Pettit, M2, or Peter Farrell copmuter now, sell it later when you need to buy the PFC
• Just buy the PFC now, and get it over with

Which one you choose is entirely up to you. I still haven't decided yet.

maxpesce

I ran my Streetported 13brew w/ a stock 93fd ecu & fuel system (and still do) along w/ a downpipe, RB catback, and the DIY airbox mod for 33k miles before breaking an apex seal. The seal failure I credit as much to the generally poor quality of HAYS rebuilds as to any other reason. However part of the next rebuild will be having RC Engineering up size my injectors (to 650p/950s) and a new ECU (AEM OR Apexi PFC) to better support aprox 325rwhp (350-375fwhp). (I am to this power level limited by the AutoTrans)

Brentis

I've seen pfc and commanders go here nowadays for as little as $800. Mostly $900 though...