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16g questions

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NVdsm

Probationary Member
11
4
Nov 6, 2019
Henderson, Nevada
been on here a little while just never posted. I usually just search everything multiple times a day LOL
Anyways little backstory I have a 97 Gst manual. I have 3 inch cat back and catless down pipe, intake, Front mount intercooler and all hard piping (not a overly huge core) with a Tial bov. I have an Innovate boost controller and boost gauge. I recently picked up a genuine Evo 3big 16g and installed it.

Couple questions I have, when I took it out on wastegate pressure only I hit like 6.5 psi. Is that normal? I do live in Las Vegas so it’s hot as balls. Could that be why it’s kinda low? I did adjust the boost with my controller and got it up to 11.5 and it feels good. Pulls as hard or harder then my t25 did at 14 psi. Second question is my spooling and blow off sound is now very quiet. Before I could hear it spool and blow off. I don’t want this to seem like a ricer question haha I don’t care if it doesn’t make noise I just wanna make sure nothing may be wrong. Do I need to put a different spring in my Tial after a big 16g? Thanks for the input guys.
 
Have you done a boost leak test after installing your E316G? Start by doing this first & fixing any leaks found.
 
I don’t have a air compressor to do a boost leak test. I think a friend of mine does so I’ll see if he can help me. I did go thru and double checked all couplers and clamps.
 
Is it a real MHI 16g or a knock off. Low boost could be caused by a large boost leak or something is up with the wastegate. The wastegate actuator could be shit if its a knock off turbo, or it could be stuck open. There are a number of issues that could cause this. Start with a boost leak test and get ALL leaks fixed and report back.
 
It’s a real MHI Evo 3 big 16g. Serial number etched in it is 47. I’m trying to find someone to help with boost leak test, I’ll update soon as I get that done.
 
+1000 on the boost leak test. I also run an E316G with a 3" catback and stock wastegate. Here's what happens:

Firstly, from personal experience I can tell you that you will barely hear your BOV (when recirculated) if you have even small boost leaks, especially around the BOV and its flange/hose. After eliminating all of mine, I can hear it all the time when I let off the gas or when it opens up and closes during cruising. So definitely do the BLT, pressurize up to 20 psi and check every single flange, gasket and bolt.

Check the stock wastegate actuator on your 16G. My first one actually unthreaded itself from inside the diaphragm, causing literally no boost at all. Make sure it's nice and tight.

Lastly, due to the nature of this, the 16g WILL want to overboost (boost creep) on you. The boost controller you have doesn't allow you to set a minimum boost level, but rather, it allows you to run higher than wastegate pressure boost. However, you're already overboosting, so it's effectively not doing anything. Leave it at 15 psi. Even after porting my wastegate flapper opening and the inner channel, if I keep my pedal to the ground it will rise up to 15 psi, then start to creep to over 20 psi. In my case, with a stock ecu and no tune, I get fuel cut at 18 psi. Also having an unrestricted exhaust flow after the O2 housing (stuff like 3" downpipes and catless pipes) makes the boost creep issue even worse.

Have this in mind and be careful with the boost. You should only run like this for a short time. You either need an external wastegate or you need to mod your existing wastegate or replace it so that you can adjust it to keep the flapper shut so it can maintain target boost levels. The 16G simply likes to creep like a mofo.
 
I have a 97 Gst manual. I have 3 inch cat back and catless down pipe, intake, Front mount intercooler and all hard piping (not a overly huge core) with a Tial bov. I have an Innovate boost controller and boost gauge. I recently picked up a genuine Evo 3big 16g and installed it.

Couple questions I have, when I took it out on wastegate pressure only I hit like 6.5 psi. Is that normal?
No. The Evo III 16G actuator contains the stiffest spring available from Mitsubishi for the j-pipe turbos with a cracking pressure of around 10-11psi. Setup, barometric pressure, and ambient air temp can have an effect on the final number but it shouldn't decrease by almost 4psi when starting at a number that low.
I do live in Las Vegas so it’s hot as balls. Could that be why it’s kinda low?
Again this has some effect, but it's something like 2% per 10*f. So if you had 10psi at 70*f, you'd have 9.4psi at 100*f.
I did adjust the boost with my controller and got it up to 11.5 and it feels good. Pulls as hard or harder then my t25 did at 14 psi. Second question is my spooling and blow off sound is now very quiet. Before I could hear it spool and blow off. I don’t want this to seem like a ricer question haha I don’t care if it doesn’t make noise I just wanna make sure nothing may be wrong.
You're at a lower boost level with a larger turbo...so the turbo will be quieter, as will the pressure release- especially when using a valve that has a piston diameter that's larger than the compressor inducer. If the turbo were surge-ported you probably wouldn't hear the blow off valve at all.
Do I need to put a different spring in my Tial after a big 16g?
Nothing should've changed the engine's idle vacuum so unless the spring was incorrect all along then it should still be the same as it was.
 
I got a pretty much brand new Oem Evo 3 wastegate actuator. Friend gave it to me for a ridiculously cheap price. As mine was old looking and had been rewelded at some point on the arm. I looks hell of a lot better but didn’t fix my issue. I got a guy that can help me with a boost leak test sunday, but looking around I think my leak is on the coupler coming right off the J pipe. When I hook up to my intercooler piping it twist to the side so it’s not sitting flush. I’m gonna take everything off and see if I can’t get that sitting better and if I can and it still isn’t right I’ll do the boost leak test Sunday.
So with no leaks and new actuator I should be seeing somewhere around 10 psi? Last I tested I made it to 7.5
 
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