I think our definitions of tight would align in this case. To remove the WA arm from the flapper I had to pry it off with a flathead screwdriver. Also to reinstall it I had to grasp it with vice grips and tug it up and back onto the flapper. It is deffinetly preloaded. I will do a pull like this at wastegate pressure and then I will adjust the arm until it lines up and slides on and do another pull at wastegate pressure to see if there is any difference.

 

First. You'll need to disconnect whatever vacuum hose is connected to the nipple on the turbo's compressor discharge tube(aka j-pipe) and disconnect the hose on the WGA. Plug the 2 open hose ends for now.

Connect a length of new 4mm hose directly between the port on the WGA And the j-pipe nipple. Try a WOT run. Go ahead and try it with the way you have the actuator rod length set up presently. This will tell us exactly what spring pressure is loaded to now.

 

i need to get a boost gauge to find out how much im boosting now

 

Jdmgt35R: Yup. Boost gauge is required.

 

Ok, I just got back from doing a WOT pull running wastegate pressure with the wastegate in it's previous "preloaded" state. I did a full third gear pull from 2500-7000 RPMs and the boost went straight to 9, slowly crept up to 10, and then fell to 7-8 by redline. Just for fun I plotted the pull in virtual dyno and it was 193 hp @ 6,906 RPM's and 194 lbft @ 3,625 RPM's.

Once it cools down enough I will adjust the wastegate to where it slides on, thus remving the "preload", and do another pull to see what my wastegate spring pressure is.

I've read that stock wastegate pressure should be around 11psi, is that correct?

 

I adjusted the wastegate actuator do it lined up with the wastegate flapper arm and slid on easily. With it like that and running wastegate pressure it took a while to build up to 8 psi and then it fell to 7 psi by redline. Normal driving when I am usually hitting boost it wasn't boosting at all. I'm thinking I may have found my problem.

 

I'm having the same problem I got my gauges hook up got it tested for vac and boost leak but I'm only running 10psi. Can I just get a mbc and set it to 19 where it should be?

 

im also hitting 1bar on my evo 9 so to conclude this the wastegate was faulty?

 

1bar= 14.5 PSI. Probably nothing wrong with either your wastegate actuator or the flapper valve. My non-USDM VIII hit only 14.5# when it was new from the factory too. But, you can increase the 14.5# spring level by adjusting the actuator.

 

i check the factory settings and was suppose to be 1.5bar then tapers down a bit
but i do see alot evo 9 owners hitting mostly around 1 bar.... so if its true then getting a MBC would be better to turn up the boost higher with a good tune

 

Basically, your WG's spring pressure is just too low. Thus, regardless of whatever method you may wish to employ to control peak boost level and/or the slope of the boost curve...your turbo's WG spring pressure is just too low and needs to be increased. Do you comprendo?

The factory MHI wastegate actuators fitted to our 16G turbos are adjustable allowing a fairly wide range of spring pressure, pretension, or "preload" to be achieved. This internal spring is about a 9 PSI and is non-replaceable inside the wastegate cannister. Overtime the spring itself tends to become fatigued just as the suspension springs on a high mileage automobile lose tension. The tip of the actuator rod is threaded allowing for a range of adjustability in WG spring pressure.

You brought this thread back from the dead, so this may have been gone over in earlier posts, I don't know. Some basics: If you bought the car new does it have a lot of miles on the original actuator? The previous owner may have removed and later tried to replace the factory boost/vacuum hoses. So, run a boost leak test. Buy a factory vacuum/boost hose assembly from the dealer and install it. Test WG spring pressure level by running the gate straight off the compressor discharge pipe's nipple.

 

You are talking about the peak boost level as set by the factory on USDM IX Evos using the factory ECU/2-port BCS boost control setup, right? Even then there was a range of variance as you mentioned somewhere between 19-21#, right?

My question is did you purchase the car new and observe 1.5 bar originally and that peak boost level has lowered over time since 2006 down to a present peak level of 14.5#? Or, did you buy the car second hand and you are just now discovering that peak boost is not quite what you expect that it should be?

 

First of all, run a boost leak test(BLT). Double check all boost/vacuum hoses for tears and tight fitment. If running the factory boost control setup check for presence of the two "pills", aka restrictor orifices. Test the wastegate to establish current spring pressure level.

 

what happened was i bought it used without the boost gauge working so when i got it fixed it was boosting around 1 bar. Ive done the boost leaks and have fixed all leaks but it still holds 1 bar. i even open up a thread about my boost leak too. But i have yet to try to test the wastegate. That is my next test.

one thing though 3rd and 4th gear do boost up to 1.4barb if you accelerate
but if you start from 1st they stay close to 1.1bar all gears then tapers down

 

That's normal my friend. You won't hit peak boost in 1st and 2nd gears. I have a stock evo 8 MR and does the same thing that you described.