Resolved 14b wastegate actuator travel problems

[ThunderChild]

so im trying to finish my build up, and i was testing my WGA. the stock one i had bolted on was only moving about 10-12mm (~1/2"). this caused the flapper to only open about 25-30* which seems insufficient to me. ive tried two atock 14b actuators and ordered a new adjustable one, same story. all have very short throw and barely open the flapper.

i have not actually run the car yet, but the turbo is a rebuilt 14b with a ported ebay 7 or 8cm^2 housing (whatever the chebay 16g's come with). i ported the flapper hole, and housing back so it can open at least 90*. past that, its got a 3" turbo back exhaust and a ported punishment racing o2 housing.

i did search and found a few threads with the same issues, but no great solutions. the best one i could see is rewelding the flapper peg at a different fulcrum point, which would still decrease the actuators ability to hold the flapper closed.

pics below, will this be enough opening? it seems very slim, like it might promote creep with the other mods. if not, what are some other options, and does anyone know of a long-throw actuator aside from a holset actuator?

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Aftermarket actuator, closed

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Aftermarket actuator open fully (on a side note, this aftermarket actuator expired after about 10 actuations at 20 psi regulated)

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Factory actuator closed

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Factory actuator fully open

 

[JackStieben]

You might need to take the turbo apart and check the wastegate flap. I have the same ebay housing and the whole wastegate set up shifted and my flap fell off and launched out from my exhaust. But before that happened, it was a little loose and getting stuck causing it to be open all the time. Which gave me a terrible boost lag and constant open dump noise from my screamer pipe.

 

[ThunderChild]

with the actuator unhooked it moves freely and fully, and when i was porting and assembling i made sure it opened with loads in all directions. its just the actuator itself doesnt move far enough, IMO.

im tempted to try a holset actuator as they have a deeper pot, but i am trying to run low boost during break in. i can always just unhook the actuator.

i was contemplating picking up a chebay external and replacing the poppet valve with an arm, but i cant find much info for how far the externals actually move. (yes i know that sounds silly, but it would be adjustable pressure-wise, and theyre the same price as MHI or adjustable chebay turbo ones)

idk, im pretty frusterated right now, as this is one of the last things holding me up.

 

[JusMX141]

All MHI actuators open the flapper about 5/16" to 3/8" which is why it's hilarious when people put a fair amount of time into porting a housing "so the flapper can open all the way" even though the actuator will never let it happen, then go as far as to claim they notice an improvement in boost control when they've effectively done nothing. Doesn't matter how far the flapper opens if the wastegate hole is large enough to handle the volume of exhaust.

Fill a bucket with water- now drill a 1/2" hole at the base of the bucket. Once water starts pouring out, place your thumb over the hole....now move your thumb away from the hole about 3/8", and maybe an inch or so. Does any less water come out when your thumb is 3/8" away from the hole versus an inch? Of course not.

I've run enough shims under a stock MHI actuator in the past on certain turbos that I wasn't even certain the flapper would open or not, and the setup would still hold a rock-solid 22-23psi once the wastegate opened (as noted by the external dump).

 

[ThunderChild]

Thats fair, and it came up alot in my search results, that's just how it is. I did the porting just to be sure, and it was out so I figured cleaning things up couldn't hurt.
Still, looking at how little the travel is in the pics, I'm not convinced the actuators are opening far enough. It may be the combo of the eBay housing and mhi compressor cover putting more preload on the actuator than necessary, idk.

What do u think from the pics justin?

 

[JusMX141]

If you're using a knockoff turbine housing, you need to be using a knockoff actuator...MHI actuators aren't adjustable so they won't work properly.

Use the knockoff actuator with a straight arm and set the adjustment so the hole in the arm offsets the pin by about 50%...meaning you have to pull the arm out slightly to fit it over the pin.

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[ThunderChild]

sounds like a plan. i tried with the first one i ordered, but like i said it gave up. i think ive got another one without the adjuster, so ill give that a try. guess if it creeps ill just do some modding to the arm and actuator rod.

if not that, i may just have to move to my evo 8 or x setup sooner than i planned.

 

[ThunderChild]

well i found a good enough solution for the moment.
part of the problem was excessive preload on a factory actuator, as well as some binding due to the angle. the aftermarket actuators dont have enough thread to give proper preload or enough throw. i believe this is because of the combo of a factory compressor cover with an ebay hotside.

so what i did was took the factory actuator that was working "kind of" and straightened the arm out. when bolted up, it gives me about 1/3 of a hole of preload and the actuator went from opening about 15-20* (vs my previous thought of 25-30*) to opening approx. 40-45*. much happier and even if the preload isnt enough, i can always shim it for a bit more boost if i need.

here some pics to show the increased movement

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fully closed with 1/3 eye hole preload

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fully open @ 20psi regulated, much better

 

[JusMX141]

As long as the flapper closed all the way and sealed in the actuator's resting position, that's fine....otherwise you're going to have some extreme lag issues.

 

[ThunderChild]

As long as the flapper closed all the way and sealed in the actuator's resting position, that's fine....otherwise you're going to have some extreme lag issues.

it is for sure, once i get it up and running i may post back with some results on spool and driving characteristics. im pretty sure it will by fine now tho