cantera

currently im running a t2 swap with a walbro 255 pump, but within the next couple months im looking to get a RB t2 racing beat exhaust 3" turbo back, manual boost controller @ 10psi, and a SAFC.
im under the impression that this is safe, if tuned correctly, but im curious, with the SAFC and MBC, will i have to port my waste gate? and will i have to upgrade my injectors?

SpeedOfLife

iTrader: (16)

Yes, port your wastegate. With the REVII exhaust you will be prone to boost creeping, porting the wastegate will help with that problem. Which series turbo is it? S4 or S5? Because it's especially critical with the S4 turbo since the wg only serves one runner. I ported mine bigger two or three times, now it's about 30mm and it's FINALLY stopped creeping for the most part.

Yes, you'll want some larger injectors at least for the secondaries.

One thing you left out is a way to keep the ECU from cutting fuel. The stock ECU cuts fuel when manifold pressure is over a certain psi, which is somewhere around 8 psi I think. A fuel cut defender, a modified ECU (such as an Rtek), or a standalone EMS could each eliminate this problem. People have blown motors due to overboost fuel cut. You don't want to have the same fate.

cantera

its a s5, i didnt think id have to port it with the boost controller, but i guess it can only flow so much.
i will probably get racing beats fuel cut defender as well.
when upgrading my injectors, will i need to get different fuel rails? i dont know much about this subject

hiroichi1515

iTrader: (17)

no you will use the same rails. Just get injectors that match year car as in low imp or high imp.

j9fd3s

iTrader: (3)

with an S5 turbo you probably don't need to port the wastegate. you do need the fuel pump.

the 550/550's are ok with stock ECU and a big fuel pump but its kind of borderline. if everything is good engine, injectors, no vacuum leaks etc etc, it'll be ok. if you've got an old motor, with old injectors its probably gonna push it over the cliff.... 550/720 = really rich, and you'll need the Safc to lean it out.

SpeedOfLife

iTrader: (16)

I still disagree. The REVII system flows VERY freely. 3" downpipe and no cat? It's better to be safe.

dwb87

iTrader: (22)

Shouldn't an aftermarket FPR be used for safe measure?

SpeedOfLife

iTrader: (16)

He already has a high flow fuel pump.

dwb87

iTrader: (22)

So, he'll be able to use the stock Fuel Pressure Regulator?

Spirit-RE

iTrader: (25)

^You really don't need a fpr if you have some way of adjusting the fuel map.


Having said that, safc's scare me, as they can add more fuel, but at the same time they add more timing.




Is that setup safe, mostly yes. Is it optimal? No.

SpeedOfLife

iTrader: (16)

Don't you mean that SAFC's don't adjust timing?

To the OP: Personally I run an Rtek 2.1 (eliminates the overboost fuel cut, making a FCD unnecessary) with stock fuel map (except the Rtek manages a few details when you boost higher than stock), S4 Turbo wastegate ported to 30mm (by yours truly ), Racing Beat REVII exhaust (oh how I luv eet!), 720cc secondaries (managed pretty well by the Rtek), high flow fuel pump, and on crazy days 14psi boost (I try to keep it down to 12psi, it usually stays down there because my wastegate is ported fairly well). I built and ported (streetport) the motor myself and just recently hit the 20,000 mile mark on it.

Spirit-RE

iTrader: (25)

That's what I always assumed too. The safc messes with the afm signal, which tells the ecu its under less load then it actually is when you add fuel on a safc. So you get more fuel, and timing.

As shown:


Chart(and info) courtesy of arghx.


more info:
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/stock-s4-turbo-timing-maps-warning-those-stock-ecu-943159/

SpeedOfLife

iTrader: (16)

I see.

On top of that, a FCD (fuel cut defender) tells the ECU that the boost isn't as high as it actually is. It's really not an ideal solution.

sLiCk WiLlIe

iTrader: (10)

If you wanna be safe using the safc just retard your timing a bit. The rtek does this too.

sLiCk WiLlIe

iTrader: (10)

Its been awhile now since i had my old RX, but i ran a rtek 1.7 safc piggy backed, 720 pri, 890 sec, on a stock port motor with a BNR stage 3 boosting 15ps fmici...never had any problems with is except ocassional rich at idle, due to walboro 255.

cantera

okay, after reading all this and a friends input, ive decided im going to get a rtek. thank you for the input

j9fd3s

iTrader: (3)

my last t2 ran and s5 turbo and RB exhaust, and it wouldn't hit 8psi. the s5 turbo is WAY better about controlling boost.

j9fd3s

iTrader: (3)

HIGGI showed me logs of his, and the stock FPR probably stops adding fuel pressure around 12psi of boost.

dwb87

iTrader: (22)

Ah, alright...

SpeedOfLife

iTrader: (16)

What about a boost controller though? A manual controller especially, while cheap, won't regulate boost perfectly so I think it's important to port the wastegate. But you're right that the S5 manages boost better, I'd certainly feel better running an unported S5 turbo versus an unported S4 turbo.

j9fd3s

iTrader: (3)

i didn't use a boost controller.

SpeedOfLife

iTrader: (16)

This is why I asked: when I hooked up my manual boost controller, even at its lowest setting it raised my peak boost level by at least a couple psi and aside from that also behaved a bit differently from just using the stock wastegate configuration. OP said he wanted to run a MBC up to 10psi...

K-Tune

iTrader: (26)

Why guess? buy a wideband.

SpeedOfLife

iTrader: (16)

You'll want a datalogger, too, with a wideband, otherwise it's not doing you much good.

cantera

ive been looking into a datalogger and already have a wideband picked out.
i think i will port my waste gate just to be safe, better safe than sorry.
thank you for the feedback