home register FAQ memberlist calendar

Go Back   Turbobricks Forums > Mechanical > maintenance & nonperformance

Reply
 
Thread Tools Display Modes
Old 05-15-2018, 12:18 AM   #1
maxitoman007
Board Member
 
Join Date: Feb 2017
Location: Calgary, Alberta, Canada
Default I F*cked Up. Help Me Find the Damage...

1987 740 turbo with lots of mods.

Decided to try do a cold boost leak test and ended up getting frustrated with air leaking past the turbo seals (apparently they need oil to seal up). Forgot I still had the end cap in and tried to start the car. The car struggled to start up and I thought nothing of it (stupid stupid me) but it did end up starting and running before i realized what I had done and turned the car back off.

Now Since the car started with an end cap in, that means that a lot of air could get in from somewhere else... And I doubt its from that tiny nipple going to the pcv...

Car still has about 18mmHg vacuum warm at idle but I can't help but wonder where all that air was getting in. I have pressure tested from the turbo outlet to the throttle body and it checks out fine holding 20 psi. Haven't checked post throttle body yet, but I was hoping you guys could give me some insight on where I may have caused damage.
maxitoman007 is offline   Reply With Quote
Old 05-15-2018, 12:53 AM   #2
Lando
Arthur Digby Sellers
 
Lando's Avatar
 
Join Date: Mar 2011
Location: Rancho Relaxo
Default

Quote:
Originally Posted by maxitoman007 View Post
1987 740 turbo with lots of mods.

Decided to try do a cold boost leak test and ended up getting frustrated with air leaking past the turbo seals (apparently they need oil to seal up). Forgot I still had the end cap in and tried to start the car. The car struggled to start up and I thought nothing of it (stupid stupid me) but it did end up starting and running before i realized what I had done and turned the car back off.

Now Since the car started with an end cap in, that means that a lot of air could get in from somewhere else... And I doubt its from that tiny nipple going to the pcv...

Car still has about 18mmHg vacuum warm at idle but I can't help but wonder where all that air was getting in. I have pressure tested from the turbo outlet to the throttle body and it checks out fine holding 20 psi. Haven't checked post throttle body yet, but I was hoping you guys could give me some insight on where I may have caused damage.
Does it run any different? The only components I can think of that would fail in such conditions are intake hoses. Try pressurizing your intake again. It won't hold pressure, but you should be able to hear leaks or see them with soapy water.
__________________
Quote:
Originally Posted by amerbritcan View Post
Lando you have an enticing midriff.
Quote:
Originally Posted by 240240 View Post
get on my lawn
Lando is offline   Reply With Quote
Old 05-15-2018, 01:00 AM   #3
maxitoman007
Board Member
 
Join Date: Feb 2017
Location: Calgary, Alberta, Canada
Default

alright I'll try with the engine warmed up, to hopefully reduce blow-by. I fixed a bunch of other things before I did the test so there is really no way of comparing before and after. AFRs are good but my mpg is still quite low from what I can estimate (haven't actually calculated it). Also have heard some people say I should be seeing like 20mmHg at idle vs my 18
maxitoman007 is offline   Reply With Quote
Old 05-15-2018, 07:20 AM   #4
89_740Turbo
Board Member
 
Join Date: Apr 2018
Location: New Jersey
Default

Whats your mod list? Just curious
89_740Turbo is offline   Reply With Quote
Old 05-15-2018, 03:45 PM   #5
lummert
Board Member
 
lummert's Avatar
 
Join Date: Jan 2008
Location: Portland IN
Default

Quote:
Originally Posted by maxitoman007 View Post
alright I'll try with the engine warmed up, to hopefully reduce blow-by. I fixed a bunch of other things before I did the test so there is really no way of comparing before and after. AFRs are good but my mpg is still quite low from what I can estimate (haven't actually calculated it). Also have heard some people say I should be seeing like 20mmHg at idle vs my 18
Vacuum is dependent on the elevation above sea level.
__________________
Trying to understand stupid people is like trying to pick up a turd by the clean end.
lummert is offline   Reply With Quote
Old 05-15-2018, 04:31 PM   #6
maxitoman007
Board Member
 
Join Date: Feb 2017
Location: Calgary, Alberta, Canada
Default

Interesting, looked it up and I'm around 3400 ft above sea level. does this account for the lack of vacuum?

As for a mods list:

Ebay "60 trim" turbo
Ebay header (flange flipped)
big front mount intercooler (the bigger of the 2 common ebay sizes)
cold air intake
browntop injectors
AC delete
Hoodpipe exhaust
boost cut off bypassed
running 21 psi of boost
maxitoman007 is offline   Reply With Quote
Old 05-15-2018, 07:18 PM   #7
lummert
Board Member
 
lummert's Avatar
 
Join Date: Jan 2008
Location: Portland IN
Default

Quote:
Originally Posted by maxitoman007 View Post
Interesting, looked it up and I'm around 3400 ft above sea level. does this account for the lack of vacuum?

As for a mods list:

Ebay "60 trim" turbo
Ebay header (flange flipped)
big front mount intercooler (the bigger of the 2 common ebay sizes)
cold air intake
browntop injectors
AC delete
Hoodpipe exhaust
boost cut off bypassed
running 21 psi of boost
You would lose about 12% vacuum at that level. Or max vacuum would be about 88%.
lummert is offline   Reply With Quote
Old 05-15-2018, 07:42 PM   #8
maxitoman007
Board Member
 
Join Date: Feb 2017
Location: Calgary, Alberta, Canada
Default

So that means my vacuum is actually pretty good then?
maxitoman007 is offline   Reply With Quote
Old 05-15-2018, 08:08 PM   #9
lummert
Board Member
 
lummert's Avatar
 
Join Date: Jan 2008
Location: Portland IN
Default

Quote:
Originally Posted by maxitoman007 View Post
So that means my vacuum is actually pretty good then?
17-19 compared to 19-21.

At sea level: Atmospheric pressure: 14.70 psi, Maximum vacuum level attainable: 29.92 in/hg
at 3000 ft: Atmospheric pressure: 13.60 psi, Maximum vacuum level attainable: 26.80 in/hg
at 4000 ft: Atmospheric pressure: 12.68 psi, Maximum vacuum level attainable: 25.80 in/hg

This elevation also effects boost level.

Last edited by lummert; 05-15-2018 at 08:18 PM..
lummert is offline   Reply With Quote
Old 05-15-2018, 08:26 PM   #10
freevolvos
Board Member
 
Join Date: Jan 2011
Location: hillpoint
Default

doesn't it pull air through the i.a.c.?
freevolvos is offline   Reply With Quote
Old 05-15-2018, 08:29 PM   #11
maxitoman007
Board Member
 
Join Date: Feb 2017
Location: Calgary, Alberta, Canada
Default

iac is just a bypass around the throttle body, not another route for air to get in. end cap should have blocked all the air.
maxitoman007 is offline   Reply With Quote
Old 05-16-2018, 08:06 AM   #12
freevolvos
Board Member
 
Join Date: Jan 2011
Location: hillpoint
Default

got ya
freevolvos is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


All times are GMT -4. The time now is 04:51 AM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2018, vBulletin Solutions Inc.