TII

removing rats nest have read post on doing it but have a few questions

1 still useing the twin scroll - how to hook it up without the nest

2 diagram i have shows 4 vac lines going around to the bak of the uim but there are only three nipples can i use one that is on the front side of the uim that was going to be capped off

Wankel7

Not to sure on this...but I have a Jspec upper manifold and there are just three vac ports on the back.

Also, don't forget about the turbo oil inlet line.

James

J-Rat

iTrader: (2)

The Twin scroll is controlled by a solenoid in the vac rack...

2 possible solutions:

1. Wire it open. Advantages? Its open. Disadvantages? Go get lunch while you wait for your turbo to spool.

2. Run it to a vac source after the compressor. MIGHT still work as advertised..

TII

if i get vac from the intake manifold would it work

J-Rat

iTrader: (2)

That would constitute a port after the compressor..

NZConvertible

Take both the solenoid with the green plug and the little green and white check valve off the rack. Use vac line to plumb it up exactly as per the schematic on page 4B-53 of the FSM, i.e manifold, check valve, solenoid, actuator. Note that both the check valve and the solenoid must be arranged exactly as per the schematic or it won't work. The check valve must allow air to flow to the manifold but not from it (it has a flow arrow on it). Mount the solenoid somewhere handy and extend the wires of the green plug so it can reach the solenoid.

Not all the UIM nipples see vac, and the twin-scroll must be connected to one that does. On the front you can use the top or bottom nipples but not the middle one, and on the rear you can only use the bottom one.

jhammons01

NZ, or anybody, My check valve broke when I was removing the harness. Is this a typical part??

is it just called a check valve?

jhammons01

Get this, Check valves are $32 bucks at Mazda. any alternatives out there??

NZConvertible

You need the check valve if you want the twin-scroll to work. Any suitably sized check valve will work, and these are fairly common items in older cars that needed a lot of emissions gear. A trip to a wrecker will get you a handful of suitable check valves.

Ricer240sx

iTrader: (3)

ok, i know this is old, but instead of starting a new topic and being told to search im bringing it up!

son for my questions: what happens if u dont hook the twin scroll up?? is it bad or does it not matter?? what exactly does the twinscroll do??

hondahater

iTrader: (2)

just to let anyone know and not saying it will be the same on your car and not wanting someone to jump down my throat *cough*cough*NZConvertable*cough*cough* I took my twin scroll out and didn't notice any great effect in the way my turbo spooled up. Maybe about 1 to 200 rpm later, to me no bigy but to someone else it may be too much.

TII '87

I'm planning on removing it too, but I'll try to pick up a S5 manifold instead ( they didn't have twin scroll right? )

if you remove your twin scroll actuator, you should port the turbo' s runners while your down there...

I'm planning to remove this system simply for simplicity, I'm sick of seeing all those vacuum hoses everywhere!

HAILERS

If the twin scroll actuator is not connected to the solenoid, the actuator goes to a spring loaded open position.

Or another way of saying it.....no vacuum to the actuator means the twin scroll flap will go to the full open position. That is where it is on a fully functional system when the rpms are over 2800 rpm.

The turbo manifold has two passages to the compressor wheel. Below 2800 rpm the FLAP operated by the twin scroll actuator blocks one of the two passages causing a higher velocity thru the remaining passagae to the compressor wheel which in turn gives you quicker boost. Something like that.

Bottom line: If you want to see the effect of having/not having a twin scroll actuator, then just disconnect the vacuum line to the actuator and drive the car. The FLAP will be spring loaded to the wide open position, much like it not being there.

full-cruise

iTrader: (5)

im with hondahater on this one.. i didnt notice much of a diff.

NZConvertible

Did you test it to see if it was working before removing it? If it wasn't working before, how would you know if removing it made a difference?

gingenhagen

Reading through the Yamaguchi book...without the twin-scroll system, turbo would have been able to achieve only 160-165 bhp safely, otherwise increasing boost leads to detonation.

NZConvertible

I haven't got the book at hand to confirm, but I think you've misunderstood that comment slightly. Mazda obviously had both power and response goals, and with the turbo technology available at the time were not able to meet both. A smaller turbo (faster response) would only make 160-165hp at the desired max boost, needing more boost to meet the power target and risk detonation. A bigger turbo (more power) would be too laggy. The answer was to incorperate a system to make the big turbo less laggy, hence the twin-scroll system.

hondahater

iTrader: (2)

Well like I said, before I removed it my turbo would spool 200rpm sooner and I did test it per the fsm manual and it worked perfectly. Before I knew how to test it I bought a new silenoid, check valve and rerouted my vac line to make sure it was getting good vacuum and it was all working fine.

Tofuball

Check valves for aquariums are 92 cents at Wal~Mart.

Same bloody thing

hondahater

iTrader: (2)

I believe I got this one for free off of a fellow forum member, I can't really remember though.....Oh yeah, the guy I bought the silenoid from automatically just threw the check valve in for free I believe. THanks for looking out though

Tofuball

NP: I just want everyone to know aquarium stuff works! Sometimes it's better stuff
Like the vac Ts are 70 cents or so at Wal~Mart aquariums and $3 at advanced auto for some that arent as good.

I wouldnt reccomend using aquarium tubing (Though its ultra cheep) because it is weaker then the vac tubing and sensitive to heat. (Though you CAN use it)