Will a stronger psi wga help stop the 34mm flapper problem?

[bob123131]

I have heard hearsay that getting a stonger wga will help stop my 34mm flapper on the eov 3 16gt from blowing open, but after much searching no definate answers. Wondering what people's opinion are on it, maybe i can get it and answer the question. Also if any one is running it what psi spring did u go with. Currently at 19psi creep to 21 my power curve drops off at like a 40 degree angle after 5400 rpms and it did the same at 17psi. Any help would be apreciated.

 

[talondave]

If your holding boost from 19-21lbs and your loosing power i dont think its your wastegate!
Around that rpm is when the 16g's loose airflow. I had a big 16g and did the same thing, switched to a biger turbo (20g) and pulled alot harder after 5500rpm's at the same boost level.

 

[bob123131]

Yea, i understand and agree, but the MHI, without the 34mm flapper dont seem to have this problem at all. There also alot of topics on the 34mm flapper blowing open early so i know im not the only person with the problem, its just there is little stated on how to fix it. Also when i say it drops off i mean it drops off i dont have the sheet handy but im talking 300 whp at 5400 and 220 at 6k.

Also the cams, and shorter length of the evo 3 intake mani, on my car should help level that curve

 

[JusMX141]

You're only able to hold roughly double the actuator's spring tension before the boost level begins doing some goofy things. Normally it will spike or drop as a result of not enough spring tension....the bigger flapper makes this even more of an issue as there's more surface area for the boost pressure to force the flapper open.

What happens is once the actuator finally gives into the force pressing against it and opens, the spring isn't strong enough to pull the flapper back shut again as the airflow continues through the wastegate and the boost level drops. The wastegate should open hard at 20psi (or whatever your MBC is set to) in order to stop boost that is climbing rapidly, and slowly close as the RPM's climb so it does not let too much boost escape. When too much boost escapes, your boost level will drop.

The Holset / Mitsu Hybrid Actuator that I designed has effectively made 24psi without spikes or drops on a customer's FP 18G, and I believe all of those turbos use a 34mm flapper. I wouldn't think there would be much difference in the compressor's ability to produce boost at higher levels between the Evo III 16G and the 18G. One of my turbo rebuild customers ran an Evo III 16G at 30psi with an external gate off the o2 housing on his FWD 2G, and I believe it only lost 3psi by redline....so I know what the Evo III is capable of.

 

[bob123131]

Thanks for the information Jusmax so if i understood you right a stronger actuator would infact help to keep the flapper closed, or at least to help it slowing close as after i have hit a constant boost? Just curious what i can do besides go get a stock 7cm housing.

 

[amg_dragon]

I'm interested in that hybrid actuator as well. On a side note (also how I found this thread), My almost new FPE316G that I paid to have ported and a 34mm installed had 2 bolts snap off when I pulled the motor. All despite using high temp anti-seize during the install ~500 miles ago. I also have an Evo III GT that came with the car but the shaft wobbles like a bad oar lock! My question, other than more information on the hybrid actuator, is it possible/advisable to use the GT hotside and save having the bolts drilled out? Sorry for the highjacking but it seems like jusmx141 might know the answer to both questions.

 

[bob123131]

by all means go ahead and steal it one thing that might help you if you have a similar problem as i do, is to put washers on the mounting bracket for the actuator.

 

[turbo addict]

2 or 3 washers and hold 37psi on a e316g. For me anyway.

 

[amg_dragon]

Wouldn't you still get spikes though?

 

[wishihadatalon]

2 or 3 washers and hold 37psi on a e316g. For me anyway.

Same here but that pretty much means that you aren't running a wastegate which is hardly ideal.

 

[JusMX141]

You'd probably get spikes, yes.

Adding preload using washers or adjusting the arm tighter (if possible) effectively raises the spring tension a little, but it also shortens the arm travel and delays the opening of the wastegate because more air pressure is needed in the actuator head to push the wastegate open.


Turbo addict, I'd love to see a shimmed OEM wastegate actuator that got you to hold 37psi on a 16G. I've seen cases where 37psi couldn't be generated by a 16G with the flapper welded shut.

 

[toofast82]

2 or 3 washers and hold 37psi on a e316g. For me anyway.

I bet its real efficient at this level
Do you have a video of this happening?

 

[matthewdesigns]

I've got an unported E316g, wastegate shimmed out with 2 washers, and it will hold 27psi after spiking to ~32psi. I think that Justin's hybrid actuator is the best sounding solution to this problem, but finding the appropriate wastegate to modify has been challenging to say the least. I've been looking for a month .

 

[GPTourer]

Currently at 19psi creep to 21 my power curve drops off at like a 40 degree angle after 5400 rpms and it did the same at 17psi. Any help would be apreciated.

So you are able to hold 19-21 to redline? Wow. My 34mm flappered MHI Evo3 would drop to 16psi by redline. I decided against shims and welded it shut and went with an external. I think something else needs attention rather then the WG. I guess I'm not understanding what the WG arm will correct if you already hold the desired boost pressure. Your tune just isn't taking advatange of the big end of the tach.

 

[turbo addict]

this isn't tough guys. a turbo is an air pump. I have a 3" that comes out in front of the rear wheel, a external dump for the wastegate port, I ported the crap out the the intake and exhaust housings, and a big intake and a little air scoop that helps the turbo breath. Also have a big filter. before I did the intake mods I was stuck at 32ish psi. The way it is now I unhooked the wastegate and pegged my gauge 45psi+. I'm sure that i could make more power with a bigger turbo. But my power under the curve is great and being in a mirage turbo i don't really need any more, no traction now. It is nice to roll race and either never shift or shift only once. The car pulls from 3000-3100rpm to 8800rpm. I could probably run a little more boost but i am running into ignition problems after 37psi.