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My guess would be that a properly designed stiffer actuator would come with a larger diameter diaphragm so that the opening a closing forces would still be balanced.

Nope, same size internally, just a stiffer spring.

What I was eluding to is the actuators that are adjustable length have a variable rate spring inside so tension increases as the rod shortens. Putting an adjustable rod on an OEM actuator "that doesn't have a variable rate spring" inside will just reduce the flap opening angle and certainly cause boost creep. In this instance I would feel the additional external spring would be better(just changing minimum boost rather than causing boost creep).

The adjustable actuator I used increases the opening angle of the puck by a fair margin, but that is because the body of the actuator is longer.

Variable rate spring? You mean the spring is thinner at one end? Never seen that before, and I have no idea why it would be necessary.

The tension of all springs increase as they are compressed.

All a variable rate spring would do; is allow the wastegate to unseat earlier.

I rather like the idea of a double acting actuator, and a 3 port boost control solenoid.

This allows you to hold boost pressure hard against the wastegate, holding it closed right up until the point you want the wastegate to open; when it switches the pressure signal to the opening side of the actuator.

The tension of all springs increase as they are compressed.

All a variable rate spring would do; is allow the wastegate to unseat earlier.

I rather like the idea of a double acting actuator, and a 3 port boost control solenoid.

This allows you to hold boost pressure hard against the wastegate, holding it closed right up until the point you want the wastegate to open; when it switches the pressure signal to the opening side of the actuator.

I thought about making a double port actuator with the billet kinugawa actuator I have. It wasn't necessary in the end, but it looks fairly easy to do. There's a hole in the casing behind the diaphragm that could easily be tapped, then screw in a barbed fitting.

The tension of all springs increase as they are compressed.

All a variable rate spring would do; is allow the wastegate to unseat earlier.

I rather like the idea of a double acting actuator, and a 3 port boost control solenoid.

This allows you to hold boost pressure hard against the wastegate, holding it closed right up until the point you want the wastegate to open; when it switches the pressure signal to the opening side of the actuator.

My external gate setup used exactly this, most people scoffed as to why I used a 5 port solenoid, but it worked very well. Getting it to work on an internal gate would be difficult as not many have a seal around the shaft with twin ports. Certainly not the Kinugawa, Turbosmart do make one but it's expensive, and not many really understand it's capabilities. Only really needed for running high boost with a low tension spring that would normally blow open.

The coil diameter is smaller at one end. It enables a further non linear pressure relationship(almost exponential) in turn giving an actuator a higher adjustment range without inducing boost creep due to flap opening angle travel restriction

  • Like 1

Using preload to bump the boost up is just plain wrong, it limits the travel of the puck, so your standard adjustable actuator won't actually work as well as adding a plain tension spring imo. I have had no issues holding good boost with mine on a great number of cars, but it does depend on the mods as to what boost it holds, as it would if a stiff aftermarket actuator is used.

If you increase the size of the wastegate you need to increase the spring tension, as the manifold pressure is pushing on a larger area. Otherwise your stock actuator will struggle to hold boost as I found on many cars before adding external springs.

None of the good wastegates I work with, mainly Turbosmart internal or external, have tapered springs, they are only fitted to oem style actuators as the diaphragm is so small at that end. Turbosmart, like mine allow differing springs to be used rather than relying on the one exponential style that you seem to like so much. These are not common in any aftermarket actuators I have worked on, and for good reason.

I think you may be focused on external gates.

I agree a bigger surface area puck requires more force.

I absolutely disagree that no good wastegates canisters use a progressive spring. In fact the best turbo in the world(IMO) use exactly that. Borg Warner EFR and with adjustable preload. They work so well, external gate is not required in most applications.

post-49288-14472256165792_thumb.jpg

Opps this goes with the pic above. Cut and pasted description

"They are capable of handling an infinitely wider range of boost pressure, more reliably, than the OEM style actuators"

I should mention I feel Scotty's spring mod on the OEM gate to be a better option than a shorter rod to the canister since it is likely the canister has a non tapered spring.

Edited by BoostdR

I absolutely disagree that no good wastegates canisters use a progressive spring. In fact the best turbo in the world(IMO) use exactly that. Borg Warner EFR and with adjustable preload. They work so well, external gate is not required in most applications.

They work well because they actually thought about gate flow, and didn't expect a hole at a 90 degree to flow any decent amount. If there was no pressure in the manifold the standard internal gate would flow backwards. I can guarantee any spring setup would work in that EFR, great flowing design, shame they made it too long to fit in our car.

  • Like 1

Putting up some thoughts about the M35 Turbocharger high flow profiles. Since majority voted GT3071R to be the best CHRA. I will be offer that instead. By current Garrett pricing, the cost of this high flow service is $1290.

Service includes machinery service to OEM factory compressor housing, turbine housing, custom pressure plate to suit comp cover, 36mm billet internal waste gate and gate porting.

Note GT3071R ball bearing CHRA is 17mm shorter then OEM, it will need aftermarket water and oil fittings that you can purchase from Nordan hydraulics and Pirtek. We will be clock the housings over a jig so housings will be lined up perfectly. We don't do sand blasting of the OEM housings, so if you want them to looks like brand new you are welcome to sand blast them prior sending them over.

I will also provide Garrett's receipt of the CHRA for every single turbocharger high flowed, in case of any CHRA issues you are covered by what ever warranty arrangements at your local Garrett dealers.

lol. You might want to fit one to your car first and see what else won't bolt up. 17mm doesn't seem like a lot, but in the M35 it is.

As there have only been one or two GT3071 Garrett upgrades I can't see how that's a majority... All this after you told me shoving a Garrett core in would cause premature failure due to exhaust backpressure?

They are not going to handle 30psi or like the heat. Running them under 20psi and keep your AFR rich. it will work fine. I might be making some adapters to bring out that 17mm, but for time been intake and cooler pipe needs to be adjusted to suit this turbo.

Its a small frame T3x ball bearing turbo, it should be pretty happy working with stock Auto.

I might be making some adapters to bring out that 17mm, but for time been intake and cooler pipe needs to be adjusted to suit this turbo.

So how is a customer going to lengthen the alloy hot side outlet pipe by 20mm to clear the driveshaft?

You are the one selling turbo's to suit the M35, you should be making sure they will fit and work long term without issue. This has always been my issue with Hypergear turbos, the customer is on his own once payment is made, and the install costs start skyrocketing.

  • Like 1

If i buy a vehicle specific brake kit i expect it to come with brake lines. If i buy an intercooler kit i expect it to come with piping. How come if i buy a turbo kit i have to go searching for the extra lines to make it work ?

The only fitment issue from early days was the bearing housing rotation position. Thats long fix now using a Jig.

With the GT3071R Centered M35 high flows, since there are few people using it I don't think there should be too much issue. I will be fitting one soon, and supply the fitting pack with the turbocharger.

Will u still be offering the small bush high flow u have spoken of before? I think you said similar power to stock but with more torque. Not everyone is after 250 or 300kw @ the wheels. If my stock turbo fails I would like something as close to stock size as possible for a reasonable price. Just asking the question. I believe there would be quite a few people who would want to go down this path considering the very limited and expensive options there is for tuning an m35

  • Like 1

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