why is my "stock" boost extremely high?

[wadiad]

I just got a boost gauge installed in my sr20 s14, and i realized my boost is going VERY high if i rev it up to the redline or even close. I think it hit 1.7- bar or more, and i am really concerned about this as i'm sure it can make short work of my engine. Without doing the exact psi conversion, i know .85 bar is ~15.2 psi, and 1.05 bar is ~18 psi, so this is very roughly around 30 psi.

I have a gt3071r turbo with a tail 38mm wastegate. I just had an HKS evc-4 boost controller installed at the same time as the boost gauge (which is actually a blitz turbo timer with a gauge in it). However, even with the boost controller turned off the boost is shooting up like this. Judging by how the car felt before and after, i am pretty sure it was doing this before i even had the boost controller, although i didn't have any gauge to read it on.

Now that i'm aware of this i'm just not revving the car much past 4k so the boost doesn't surge up, but i would really appciate any help so i can get it back to its proper wastegate boost.

Thanks.

[otterman]

I'm not sure what the stock boost is on the GT30 but heres the conversions you were talking about.

1 bar = 14.5psi.85 = 12.31.05 = 15.2

30 psi = 2.07bar

[srpowered240sx]

bypass your boost controller and go straight wastegate pressure. this will determine whats not working right.

[wadiad]

Thanks for the correction. I believe at its highest, my boost did come near 2 bar (the turbo timer has a peak-hold feature, and it was 1.9 just before a hose blew off :-)

[wadiad]

So do you mean to just turn the boost controller off, or do something more? Because i already tried it with the controller off and it's no different.

[da40]

I just got a boost gauge installed in my sr20 s14, and i realized my boost is going VERY high if i rev it up to the redline or even close. I think it hit 1.7- bar or more, and i am really concerned about this as i'm sure it can make short work of my engine. Without doing the exact psi conversion, i know .85 bar is ~15.2 psi, and 1.05 bar is ~18 psi, so this is very roughly around 30 psi.

I have a gt3071r turbo with a tail 38mm wastegate. I just had an HKS evc-4 boost controller installed at the same time as the boost gauge (which is actually a blitz turbo timer with a gauge in it). However, even with the boost controller turned off the boost is shooting up like this. Judging by how the car felt before and after, i am pretty sure it was doing this before i even had the boost controller, although i didn't have any gauge to read it on.

Now that i'm aware of this i'm just not revving the car much past 4k so the boost doesn't surge up, but i would really appciate any help so i can get it back to its proper wastegate boost.

Thanks.

have u checked ur lines making sure everything is tight,and all the hoses are where the suppose to go ,maybe check for a loose or cracked vac line

[srpowered240sx]

So do you mean to just turn the boost controller off, or do something more? Because i already tried it with the controller off and it's no different.

no, bypass the controller. run your pressure signal line (from charge pipe or on most turbos the outlet going to the hot pipe) straight to your wastegate. take the controller out of the equation and see if it will drop back down to a normal boost amount. what is your tial wastegate spring popoff boost pressure??

[wadiad]

have u checked ur lines making sure everything is tight,and all the hoses are where the suppose to go ,maybe check for a loose or cracked vac line

A few days ago i was having a problem that my boost gauge was displaying 0.00 constantly, so to address that problem i did check the vacuum lines pretty thoroughly (turns out one which connects to the underside of the throttle body had come off and that was causing the problem). But yes, everything else looked good.

[wadiad]

no, bypass the controller. run your pressure signal line (from charge pipe or on most turbos the outlet going to the hot pipe) straight to your wastegate. take the controller out of the equation and see if it will drop back down to a normal boost amount. what is your tial wastegate spring popoff boost pressure??

Bypassing the controller sounds like a good idea. I will try it. Honestly i bought the car like this (minus the controller) and i don't know the spring's popoff boost pressure. Aside from asking the previous owner, who i can't get a hold of, is there any way to determine this amount?

I just dropped the car off at a shop for some exhaust work, and i should have it back tomorrow evening (only to go to another shop Wednesday morning). I'll try your recommendations at that time and then post a follow-up.

[norcals14]

well if you take the pressure hose that you have going into the boost controller solenoid and connect it instead to the wastegate (supposing your wastegate isn't fahkd) your peak boost will be your springs pressure... it sounds as though either you didn't run your lines right or you didn't set up your boost controller right... and if you still show real high boost after those checks find someone who has a known good boost gauge and hook it up to your blitz solenoid... if it now shows good boost pressures then its your gauge... if it doesn't, take your friends solenoid too... i would be a little iffy on using the combo meal gadgets...

[S14-NEO]

wouldnt be a bad idea to find out what spring you have in your wastegate too..to run jsut gate pressure and bypass your bosot controller jsut runa vaccum line from your intake manifold to your wastegate and youll be able to tell that waywhat you baseline boost pressure is or gate pressure.

[norcals14]

i hear an echo...

[wadiad]

S#!* i forgot to post a follow up - sorry about that! I didn't think anyone was still looking at this thread because it's kind of old. The problem was that there was some kind of complete blockage in the vacuum hose to the wastegate (actually part of the hose itself had "chipped" off and was plugging it up) and that was causing the wastegate never to open. I feel very fortunate that i got up to 2.44 bar without doing any damage worse than blowing a hose off. Anyway, the problem is now fixed and it's boosting at whatever i set the controller at without issues.

Thanks to everyone for your help.