87_RX7_fc3s

I'm currently in the process of removing the spider vac line. Do you know if i need the twin scroll solenoid (its the green one), will removing it have a negative effect on the way the car runs? I have already yanked all the other solenoids and the rest of the emissions stuff.

thejallenator

iTrader: (14)

http://www.rotaryresurrection.com/2n...s_removal.html

RotaryRocket88

iTrader: (7)

It's not an NA ^.

The twin scroll solenoid allows vacuum to be applied to the twin scroll actuator under 2700 RPM. This closes off one of the runners in the turbo's turbine housing, which increases exhaust gas velocity & promotes quicker boost response down low. Above 2700 RPM, the flapper door is always open, so you wouldn't notice any difference at all in the mid to upper RPM range. And since it works on vacuum, the default actuator position should have the door open. So if you remove the solenoid, the door shouldn't move around at all, it should just stay in the open position at all times.

87_RX7_fc3s

OK... well I guess I will have to keep it in order to keep some low end turbo response... I noticed that the Grey solenoid was tied into the same vac lines.... Could I just grab a new vac source to use with the twin scroll... or will it only function if I have the gray and green solenoids together?

HAILERS2

The grey switching solenoid has nothing to do with the twin scroll. The switching solenoid controls part of the ACV functions.

RX-7tII88

iTrader: (1)

Ive been wondering on this for my car. Can someone else clarify that it is open if
disconnected. I dont want to have to deal with removing it completely at the moment, but it is
not hooked up properly in my car. I just got it back up and running.

S4 Vert

It really pays off to search old threads on this site .

I think this may be the reason I am not getting low end boost. I do get boost at higher rpms, and when I mash the gas pedal from a standing start, but it's not instant boost response, it comes on at may 4krpm.

Sometimes though I do get a dose of low end boost and it's real brief and goes away instantly like it's being cut off. So now I am thinking the twin scroll solenoid is either disconnected, or faulty.

Enlighten me please.

VANHALEN

iTrader: (3)

When doing the rats nest, you can remove /plug everything except the twin scroll solenoid valve (green ?). ****...it's been over 10 years since I did this. You need the twin scroll if you are keeping the S4 manifold. Your low end is gonna suck. If you have the turbo out, bore the wastegate just enough for the flapper to close shut. You'll be amazed how small it is.

S4 Vert

I just performed my first 13B T swap and I am still trying to work out the bugs in the engine. I am finding little things that are wrong and fixing them as I go a long. I am not getting any boost at low rpms, I hear the inducer blades whistling but not boost. I do not plan on removing the rats nest anytime soon, I just want my engine to run like it should stock.

I do plan on having the waste gate bored to 32,or 35mm (BNR specs), but for now I am keeping everything stock. Or I may just decide to upgrade to an BNR Stage 1, or 2 turbocharger.

Thank you for the advice.

VANHALEN

iTrader: (3)

Boost comes on very early on these cars...about 2700 rpm.
Check if there's a vacuum line going to the solenoid valve (green ?). Under the car, the switching actuator rod is attached to the turbo manifold via c-clips. See if it's attached.

S4 Vert

Awesome! Will do that, and I am hoping the problem lies there. Yep I am not getting any boost until around 4k, then I feel it.

VANHALEN

iTrader: (3)

It's a really simple design activated by vacuum and sping. Make sure that check valve is there too near solenoid valve. If not, any one way check valve will do.
Let's hope that clears it up. If not, something's not working.

If you can see the switching actuator rod, rev it past 2700 and it should move each time you rev it past 2700rpm.

S4 Vert

Thanks for that tip .

That seems like the easiest way to detect what the problem is and from there I should be able to trace down the exact problem.

wthdidusay82

iTrader: (15)

I'm running an s5 Turbo so I don't have to worry about this?

I do know people talk about a restrictor pill as well, which I dont if my car has, where it goes or what purpose it serves. I'd think its near the boost sensor.

VANHALEN

iTrader: (3)

Well, they're both twin scroll but the S5 is a simpler design using equal runners and no actuator.
That pill is a restrictor for the boost sensor. If you have the original vacuum line, there's a tiny restrictor inside the line. It's just to smooth out pulses when you mash the gas pedal instead of a burst of air slamming into it.
You may have felt a bog /hesitation when you mashed the gas pedal. Really isn't necessary but you can pick it up at any parts store.

wthdidusay82

iTrader: (15)

So it basically gives the boost sensor a better reading.

VANHALEN

iTrader: (3)

Yup...smoother reading.
Most people don't even feel it. I've worked on one with no restrictor, bone stock TII and I didn't feel it.

wthdidusay82

iTrader: (15)

I say if it came with it and is helpful why not keep it.

I am going to get rid of all my emissions airpump etc, only thing I will keep is the power steering.

I'd remove it but I don't want it to be done ghetto like my last NA.

S4 Vert

I checked the actuator rod today as I revved my engine. It moved freely each time I revved the engine, but I am still not getting any low end boost. My boost is coming on at 3k-4k.

I checked the twin scroll solenoid and check valve, everything is in place and looks good. My idle was real crappy today (below 900rpm and bobbling), my engine was ready to shut off every time I was coming to a stop, or sitting at the stop light.

What do you think the problem is? At this point I am ready to take my car to an RE shop and have them find and fix the problem(s). BUT before I take my car to the shop I will jack my car up and see if the rod is actually attached.

VANHALEN

iTrader: (3)

When you said "today", was it running ok before?
Sounds like your car is running lean. The connector is on the solenoid (doesn't affect lean or rich) ??

Next to the pass. shock tower , there's a black resisitor with a flat head screw to richen / lean. With the car idling , turn it counter clockwise (it will start to idle rough) then slowly turn it clockwise until it smoothes out. Before doing this see if you can get it close to 750rpm as you can.
Your TPS checks out ok?

S4 Vert

My engine has been running like this since I took my car to the shop to have some work done. Additional work was done, ie the oxygen sensor connection at the engine was disconnected, the air bypass solenoid valve was disconnected and capped off, and I'm guessing the idle was adjusted as well.

Before my engine idled well but since then it idles very low on cold starts, where as before it idled above 1k rpm until the engine warned up then the idle would drop down to 1krpm, or 900 rpm. So like you said it's possible the mechanic leaned out my engine

I will look into my TPS and try adjustments on the resistor at the passenger shock tower.

Once again thank you .

VANHALEN

iTrader: (3)

That is possible. Before you adjust the mixture, get the engine to normal temp. first.

Did you have the emissions removed? That will cause low idle on cold starts since the cold asisit is disabled. No way around that. No biggy though.

Soooo...check the TPS, get the engine close to 750 and check timing....then use the mixture screw in that order. They're plastic and it stops at a point so don't force it.
Good luck

VANHALEN

iTrader: (3)

If you have a hard time to get it to idle from leaning out, use the mixture screw and go back to it after setting everything. Lean it all the way (counterclockwise) and slowly turn it other way to richen it up.

S4 Vert

The only emissions parts that have been removed is the catalytic convertors. The oxygen sensor was disconnected without my knowing and so was the air bypass solenoid valve. I was told the air bypass solenoid valve would only effect the air conditioner,( which I removed) and that it would not be an issue. Other then that the air pump, acv and everything else is still in place.

The cold start assist was removed by me during the swap, but my engine idled well (1k-1.5k rpm) on cold starts before I took my car to the shop. And the work that was done at the shop was a replacement of the gasket between the turbo charger and manifold. The mechanic did some other work on his own which resulted in the problems I am having now.

I will try the steps you have given me and I hope that will fix the idle, hot start, and stalling issues. Then it's the matter of fixing the absence of no boost at low rpms .

VANHALEN

iTrader: (3)

Whoa...he said what about the air bypass valve??

That is to assist in the cold assist on cold start up. ..not the A/C. The oly thing to"assist" the A/C is the BAC valve .

Did you have the boost problem before taking it to the shop ??

I saw you live Cal so you need the emissions stuff.
How were you able to pass without the cat???

Damn...the torture your state puts its citizens through.