IWG75 Universal 150mm rod 14 PSI Black

Turbosmart sell universal fitment internal wastegate actuators with replaceable springs to choose between 3 and 26psi

 

Nice find. Would be great to see if anyone here has tried this out.

 

I have one now. Just making up an adapter bracket tomorrow all going well. Wastegate will be easy I think. Pre control not so easy

 

Cool, keep us updated. Are you going with the 14psi spring/preload?

 

I don't know what psi or even what car it was for. Some guy bought it couldn't get it to work so went external gated. Its basically new, only a few failed dyno pulls old. He said it is 12-14psi. I will have to pull the springs out to see.

Also have some highflow twins going on!

For the prespool bracket I will use the bracket cut off an original precontrol actuator I think.

I'm just going the gate first tho.

 

Would love to see some pics

 

Wastegate bracket is made and bolts on. Not sure whether the rod lines up yet.

I disassembled the IWG75. It has the 5psi inner spring (Brown and Gray paint), and the 7psi middle spring (Brown and Purple).

This is pretty much perfect for my setup anyway. EBC will just about allow double that, and if I want more I just buy an extra spring.

Pics before Monday but I will get some up.

 

This shows fitment on a '1999 - 2002' spec 280PS twin turbo compressor cover, N3G1 / aka HT12-3B

I have tested it with compressed air and it does not get as much lift as the original wastegate actuator because the rod is slightly short and the IWG75 bottoms out before the full travel. If the clevis (the threaded adjuster bit) was longer it wouldn't be as much of an issue.

I might put up a movie link also.

 

oh wow, that looks great!!! keep us updated!

 

Uploading a movie to youtube at the moment. Its boring just showing the actuator working.

 

 

Sorry for the noob question Jobro, but I'm trying to figure out how the turbosmart wastegate actuator works compared to the stock one. The stock one has an pressure inlet and outlet "nipple" and the turbosmart one just has the pressure inlet.

Quote from Rob Robinette's site: "The 3rd gen RX-7 uses an "open loop," non-feedback boost controller. The wastegate, which diverts exhaust away from the turbos, is controlled by a combination of air pressure and the engine's ECU. Air pressure in the wastegate actuator opens the wastegate. The higher the pressure the more the wastegate opens. Airflow "in" to the wastegate actuator comes from the turbos themselves and is reduced by a restrictor pill in the vacuum line between the primary turbo and the wastegate actuator. Airflow "out" of the wastegate actuator is regulated by a solenoid that is rapidly cycled open and closed at a rate dictated by maps in the ECU."

So the stock wastegate actuator vents pressure to the wastegate control solenoid that is cycled by the ECU. So if the turbosmart actuator just vents out, how does this affect the system?

When I think about it, the turbosmart actuator makes more sense by just venting out, compared to the stock actuator that vents to the solenoid that is cycled by the ECU...

To rephrase my question...why does the stock wategate actuator vent to the ECU controlled solenoid? Is it to better control the actuator when closing the wastegate?

 

^^Very nice & clean adaptation Jobro. I think you'll like the results.


Not to jack your thread, but here's what I did back in the day; prior to the availability of these custom WG pieces--I guess it's now officially a poor man's mod, lol.

What I found (and the reason I did this) is that the WG can blow open rather early, especially when ported.

The helper springs about doubled the original load and set the WG's at 0.9bar (on spring only). It actually worked out quite well.

 

Oh and thanks for the pics, and the video is great!

 

To answer your question spalato, the ECU controlled solenoid bleeds pressure away from the wastegate can just like most forms of electronic boost control. If you wanted to replicate this and control it 'like stock' you'd get a 6mm t piece and put a small restriction feeding the t, one port to the single port actuator and one port to the factory 2 port solenoid. I had boost overshoot and also bleed off in the too with OEM control as soon as I installed an autoexe airbox. I have now drilled out the pills in the turbo covers to 4.5mm. I'm still undecided how I will plumb it. I could put the gate straight through and use my EBC on the precontrol now

I found out last night the actuator I have used is from a Ford XR6 Turbo. It is advertised as 135mm long which is a smidge short. Of interest there is one sold for a Mazda protégé Turbo listed as 143mm long that may suit more.

Does anyone have any thoughts on whether I have enough lift?

 

With regards to lift, I can tell you that flow bench work has shown that most of the WG flow action takes place by about 30 to 40 degrees of flapper opening; beyond this, flow increases diminish rapidly. I wouldn't waste time on anything over 50 or 60 degrees of opening as flow is already maxed at that point. (Note that The inside of the primary housing can be relieved to increase main WG lift somewhat, if necessary--and don't worry about the limited pre-spool lift as it hasn't proven to be a problem.)

 

Do you think I have 50 degrees based off the movie?

 

When the actuator arm and the waste gate arm are at 90 deg. the diaphragm is at it's maximum pushing strength any thing past that the power of the diaphragm will be reduced dramatically as the rod travels past the 90 deg. point .. so JMO but the wastegate should start to open just before the rod reaches 90 deg and should be fully open to the decided 50 or 60 deg waste gate opening just past 90 deg. on the rod , this way you are using the max power the diaphragm can deliver in getting the gate started to open and helping prevent slow opening ,, it would seem to me the further the gate is opened the less force it should take to move it further .. .. like I said JMO. Gerald m.

 

I can tell you from my experience with electric wastegate actuators on non Rx-7's that yeah, typically the 20-30 degrees from the fully closed position has the most effect on exhaust flow and turbine speed. Although a 50 degree range is a fair enough number.

All the vacuum and electric wastegate actuators on many modern engines are normally open and then close with a duty cycle command, rather than being sprung shut and forced open with pressure. The electrics are the best, but you need an h-bridge to drive them (same kind of thing as an ECU uses to drive an electronic throttle).

 

No, your travel looks rather limited, which is typical. So I went to the garage and measured one I have on the bench; it is ~25 deg max swing stock. You can increase the swing a few degrees by grinding a relief inside the center section and it will help flow (as does porting the WG); the effort may be warranted if you expect to encounter--or want to avoid--boost creep.

 

I'd be happy with the stock level of swing. The point I'm making is that the adjustable actuator can not quite be adjusted long enough and is preloading the wastegate flapper perhaps more than I would like. This also has the side effect of the pressure actuator reaching full extension before the swing valve has bottomed out.

 

This setup is now running.

The pre control pills have been drilled and the 12psi wastegate is connected directly to the turbo outlet, so I am expecting a laggy 7psi until the secondary comes online where it shoots to 12psi.

I'm going to set a rev limit to 3200rpm because this is a fresh engine with new bearings and most other parts.

So I will have results but it might take me 4 weeks to get some running under it.

 

For my own understanding, what problem do you feel an upgraded actuator is going to solve?

David

 

I think the system will be easier to control with a more appropriately sprung wastegate

 

Too much boost but close to what I was going for. Rock solid ~16.5psi (216kpa absolute ~21500PIM) in 2nd and 3rd gears. It builds more than that in 4th gear which I'm not a fan of.

That is 4x 850cc injectors all the way to 98% duty. Hoping to eventually tune it back to 11:1 AFR, maybe 10.8:1

I had to install a standard 99 airbox to get the boost down to this level.

So the mods are

Programmable ECU
9.7:1 Rotors
4x850cc
80mm turbo back with a good cat
Mazdaspeed turbos
Turbosmart IWG75 (no boost pill)
Precontrol has 1.0mm pill (overboosts, will check 1.5mm next or use EBC)
Greddy compression tube and hard pipe on engine side only
HKS Twin Power
R7420 9 and 105 plugs

I'd prefer to re install all the flow mods and lower the boost by getting the wastegate working better. I'd be happier down at 11.5psi until I get the setup sorted

These turbos would probably justify 2x850 and 2x1300 and a Denso Supra pump.