rg42284

Can stock turbos that has been ported and polished take 14 psi of boost? What is the most it can take? The car right now is producing 377 rwhp at 14 psi. And how much will the stock injectors handle? Just how good are those xs engineering ecu's?

GoodfellaFD3S

iTrader: (213)

In my humble opinion, you're pushing it. W/my current setup, on 13# I'm seeing ~90% inj duty cycle (as measured by the PowerFC commander). That's a whole lot of rwhp for stock injectors. You're prolly at 100% toward redline.

If you're not careful, I wouldn't be surprised if you pop your motor. I would *really, really* turn down the boost to 12# until you can get injectors. 1200, 1300cc secondaries. I would also get a Power FC and commander so you can monitor all your vital functions.

There's a fuel calculator on the rx7.com site under the fuel mods section. Go check it out; I think stock injectors are like 360 wheel hp at 100%. Which means you're in the danger zone. Be careful, man....there've been way too many blown motors lately...

Mach2

Yea, Goodfella is right. I've run 14psi for a while with the stock twins, but I don't know my inj duty cycles. I'm pretty sure that they were maxed out at 100%. It was definitely pushing it, but if you've got the right upgrades for engine management and fuel then I think it's possible. I'm sure that it will put alot of stress on the turbos, but it shouldn't break anything. Btw, you need a really good IC if you're going to run that much boost. I ran 14psi through the stock IC, but that was a "terrible" idea. What kind of ECU are you running?? I remember reading about Anthony from T&R who ran 18 psi on the stock twins and pulled an 11.1 1/4mile. I think that's a little too much considering the turbos' effeciency, but 15 psi would probably be the max with a "slight" margin of safety. You must have all the upgrades though, 1300cc secondary inj, higher flowing fuel pump, PFC or Haltech, BIG IC, etc. At this level your turbos won't last as long though, but hey, you'll have an excuse to upgrade them too!!

rg42284

Right now the car is running a programmed XS engineering computer. The car is running a little rich, which is good. The turbos, keep in mind, are ported and polished so the turbos have 15% more flow that the stock ones. The car is running a Blitz SMIC. Do you still think that the turbos wont last long?

Mach2

What I meant was that I don't think that they will last 100K miles, but that doesn't mean that they'll break. I'd guess maybe 20% less lifespan. It also depends on what condition the turbos are to begin with. If you install a brand new set and change the oil every 1500miles and use a turbo timer, then you might even get 100K out of them. It all depends on how they are taken care of. Btw, I really don't like the blitz smic(no offense). It looks very little and I doubt that there is a noticeable increase in cooling when compared to the stock ic *(puts on flame suit)*. If you want to run 15psi then you need either a fmic or a big smic like the M2 that Goodfella has. If you use anything smaller then you'll be diminishing even further the life of the turbos, and start to put added stress on the engine. Good luck and be very careful. At 15 psi every thing is critical and it doesn't take much to loose an engine. Don't ask how I know.

kwikrx7

yeah, the Blitz smic can't support 15 psi for too long. It is barely larger than stock maybe 1.5-1.7 times the size of stock. they do look nice on top though. To run that much hp you'll need a bigger ic, and the entire fuel system need upgraded. 12-13 psi is max for stock injectors (85-90%) at WOT.

jackc

I ran 14 psi. for many years probally 3 yrs. I always added octane boost from NOS. With every 1/2 tank of gas. I had allot of fun with the car.
This year at the track my O2 sensor started
to go. Showed slightly lean at wot on the air/fuel gauge. In the burn out box, blew the apex seals on first rotor and some metal went into the turbos as well.
Engine got rear ported then I blew the second turbo on the street. My engine builder missed a hose to the charge control seleniod. Many more $$$ later.
Again at the Track: I blew the Diff. on the launch.w/ Drag radials. And it's taking the Dealership over a month to get all the
parts and I still do not have my car back... And the Diff will be more exspensive than a Engine...


To think all this started with a bad O2 sensor....
I think you can run 14 psi w/a good octane booster but
your fuel system has to be running perfect... Get a air/fuel meter as well... stay off the gas if you see anything slightly lean... at WOT.
Best wishes jc.

Stevil

I run 14.5psi on stock turbos. Granted I have 1200cc secondaries, PFC, CWC IC(w/duct), DP, high flow cat, Apexi duals, HKS twinpower, 50/50 alcohol/water injection, yadda, yadda yadda.
I have been doing this for a few months. Then again, I am not always boosting(street car) and dont really put that many miles on the car(avg 30 week). But, still, I am doing it.

Steve

Mach2

Stevil,
you're doing it 100% right. You're setup should last a LONG time. Btw, think about upgrading the fuel pump yet? It's a very good investment when running higher boost. Good luck!

Stevil

Oh ya, I forgot, throw in an upgraded fuel pump also(first fuel mod I did).

Now, I just need to get it fine tuned. And get my vented hood. Then I am done.

Steve