Searched and followed what others did. Cannot get mine past 12 psi on the stock setup. Replaced the bcs hose kit I ordered from the dealership because I was missing the pill closest to the bsc. Correct orientation with one boost pill on the j pipe side of the T fitting, and one close to the bcs. Reset the ecu by removing the negative battery cable and placing it on the positive battery terminal.

2003 evo 8
Sard intake and adapter
Oem inlet pipe
Replaced the bcs hoses
STM tb shaft seals
New iridium spark plugs
Tephra v7 94170715 flash

 

save your money, don't do anything until you do this. https://www.evolutionm.net/forums/ev...g-how-why.html

 

Do a big boost leak test. I had a big nasty leak at my EGR blockoff, a big leak at my turbo outlet to LICP, and a leak at my UICP to BOV.

My 9.8 housing also wasn't sealing. Slow boost, and low boost. Replaced it with a single flapper 10.5 housing. Much better.

 

Check for leaks. Esp listen for leaks around your throttle body as well, could be a throttle body seal. Test your WGA. Check the boost lines to the WGA, and verify that they are going to the correct spots. I was running 12-13 psi after I rebuilt and installed my turbo, it turned out to be that I had my boost controller hoses connected in the wrong order. and was a quick fix.

 

Checked for leaks. Intercooler piping holds steady 25 psi with the greddy type s bov recirculated with the ngr diaphram. Boost leak test was how I found the tb shaft seals to be leaking before. Slow drop in pressure when testing intake manifold I believe is normal due to the leaking through the valves with the cams installed. Also egr is still in place. Did not install the stm block off as of yet. I'm pretty much resetting the ecu every few days as I'm still working on the battery tray for my miata battery.

 

Trying to get stock power back, may flash the rom back to the one I pulled off the ecu in the first place. Or maybe jump on a 3 bar map sensor and wire up my greddy 3 port bcs.

 

How many miles on your car, OP?

 

If you start a WOT run in 4th, flooring it at 2500 RPM, by what RPM do you see 12# on your boost gauge?

 

BTW, OP, it is probably irrelevant, but, does your car have any exhaust side mods, such as test pipe, hiflow cat, aftermarket DP, or O2 hsg., etc.? Or, is that all stock?

Edit: Yeah, I realize that I seem to be padding my post count...I am. LOL

 

Def do the test. I recently did a leak down, come to find out there were a few spots I was loosing pressure from. Now car is back to normal.

 

Unsure of when it hits 12 psi at wot, exhaust mods are minimal. No cat, no res, defoulers added to prevent secondary o2 cel, one piece downpipe to what looks like a black magnaflow with chrome tip. All done by previous owner. Oem o2 housing, oem manifold with egt bung, oem 9.8 hotside turbo. Boost leak test was already done. Minor leak at intake manifold at the alternator bracket nut. Not large enough to cut boost from oem to wastegate pressure. Psi in tester doesn't drop fast enough to identify "moderate to major" leaks. Thanks.

 

Disconnect the boost/vacuum hose that is connected to the compressor discharge nipple on the j-pipe, as well as the hose that is connected to the WGA nipple. Plug both open hose ends with golf tees. Run a length of 4mm vacuum hose directly from the comp hsg discharge nipple to the nipple on the WGA. Take the car for a WOT run in 3rd, or 4th gear and report back the peak boost reading. I am guessing it'll be 10-12#.

 

Wot 4th gear hits 12psi at about 3k rpm give or take 100 rpm.

 

Should be seeing 20# in the 3000-3400 band given the 9.8cm housing, no BL's and a healthy, functional and properly preloaded WG assembly. So, yours is way off the mark.

 

See my post #12 above, and follow those steps so as to determine actual WG spring pressure. From there we will try increasing spring tension. The most likely scenario is that your turbo's WG flapper is fully open by 12# due to insufficient spring pressure, me thinks