# vacuum line to the wastegate?



## 0341TODD (Nov 15, 2003)

Hey, dumb question- but I dont think that all my boost do hickys are working properly- can I just bypass them and tap off the fuel pressure regulator line and go straight to the wastegate? Hopefully this thread will not start any crazy blast off drag races into outerspace and Chimmike wont come along and cut my posts out from under me


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## chimmike (Oct 17, 2002)

Posts are deleted when they have nothing to do with the subject. Driving off a cliff has nothing to do with differences between brembo and regular brakes. Oh, and it was just one post. If you can't get over it, I'm not the only moderator who will start to take action.


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## Chuck (Nov 19, 2003)

WOOOOPPSSHHHH - GO CHIMMIKE!!!

:but I dont think that all my boost do hickys are working properly:. Boost controller? turbo timer? blow off valve? wastegate? what exactly do you mean

:can I just bypass them and tap off the fuel pressure regulator line and go straight to the wastegate: sure, why not? as long as your wastegate is getting a vaccum source as close to the turbo as possible.. for the most acurate readings.. for example. if you have the wastegate vaccum line going all the way to the trunk (for example) it would take like.. 40 times longer for the wastegate to open up.. but if the vaccum line is only 5" long.. and has a direct vaccum source.. it would work better..


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## James (Apr 29, 2002)

I hesitate to give you an answer because I don't know what else are on those lines... my advice is to fix those "boost do hickys" instead of reinventing the wheel...


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## morepower2 (Apr 19, 2002)

0341TODD said:


> Hey, dumb question- but I dont think that all my boost do hickys are working properly- can I just bypass them and tap off the fuel pressure regulator line and go straight to the wastegate? Hopefully this thread will not start any crazy blast off drag races into outerspace and Chimmike wont come along and cut my posts out from under me


Whats your car doing wrong exactly?

Mike


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## 0341TODD (Nov 15, 2003)

Hey Dude, didnt I send you an email saying- hey atleast youre doing your job? Excuse me guys if Im not speaking as you would like- I have this sense of humor that doesnt allow me too. It may be getting too extreme for this website, so I will have to tone it down for Chimmike's sake before he has a heart attack. I was just wondering if the boost solenoid can be bypassed? Would that cause me all kinds of problems- Im assuming it would- As in running a vacuum line off the fuel pressure regulator straight to the wastegate on the turbo. Its basically just a question- I dont think I would act on it. I could see that it may work, but if the ecu couldnt read what the boost level was then wouldnt that create a fuel problem?


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## Zen31ZR (Mar 24, 2004)

0341TODD said:


> Hey Dude, didnt I send you an email saying- hey atleast youre doing your job? Excuse me guys if Im not speaking as you would like- I have this sense of humor that doesnt allow me too. It may be getting too extreme for this website, so I will have to tone it down for Chimmike's sake before he has a heart attack. I was just wondering if the boost solenoid can be bypassed? Would that cause me all kinds of problems- Im assuming it would- As in running a vacuum line off the fuel pressure regulator straight to the wastegate on the turbo. Its basically just a question- I dont think I would act on it. I could see that it may work, but if the ecu couldnt read what the boost level was then wouldnt that create a fuel problem?


The ECU doesn't read the actual psi level of boost , it only reads the increased airflow from the MAF as the turbo pulls in more air as it spools up.
It's too old of an ECU to be that complicated , it's only some of the OBD1 era cars (90 and later) that even do that. MKIV Supras do , and consequently shut off the fun at 14 psi. Its only turbo cars with MAP sensors that actually sense the boost pressure , and those are fairly easy to fool.


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## 0341TODD (Nov 15, 2003)

So Hypothetically I Could Do It And Get Away With It With No Retarded Problems-obviously It Would Still Function Properly- Like I Said, Im Not Going To Do It, Im Honestly Just Wondering If That Is Possible.


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## morepower2 (Apr 19, 2002)

0341TODD said:


> So Hypothetically I Could Do It And Get Away With It With No Retarded Problems-obviously It Would Still Function Properly- Like I Said, Im Not Going To Do It, Im Honestly Just Wondering If That Is Possible.


whats your car doing wrong? You can bypass it but it would be good to know what the problem is first.

Mike


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## Zen31ZR (Mar 24, 2004)

morepower2 said:


> whats your car doing wrong? You can bypass it but it would be good to know what the problem is first.
> 
> Mike


Yeah that whole "boost doohickeys" thing has me confused.  

Not to mention I don't really think you want to tap a line coming off the FPR to run the wastegate , somehow that just doesn't sound like a good idea. 

If you are still working with the original turbo , the wastegate line comes right off the compressor housing and goes directly to the wastegate , I think its about 4 inches long , if that. If the wastegate isn't working right (major boost spike) , that's a replacement issue.


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## James (Apr 29, 2002)

[email protected] said:


> Yeah that whole "boost doohickeys" thing has me confused.
> 
> Not to mention I don't really think you want to tap a line coming off the FPR to run the wastegate , somehow that just doesn't sound like a good idea.


its not but I have it on mine!


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## Zen31ZR (Mar 24, 2004)

James said:


> its not but I have it on mine!


Does it up the boost a touch or what. Right now I just have a bleeder valve on mine.


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## James (Apr 29, 2002)

um dunno, what do you mean by boost up a touch? 

it seems ok other than the fact I'm always worried that if the line leaks or something I'm screwed!!!


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## Zen31ZR (Mar 24, 2004)

James said:


> um dunno, what do you mean by boost up a touch?
> 
> it seems ok other than the fact I'm always worried that if the line leaks or something I'm screwed!!!


Does it run more psi like that? I'm just confused as to the merits of putting the wastgate line off the FPR.  
And yeah , not only will the wastegate not open , I think the fuel pressure will drop under boost if the FPR line leaks.


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## James (Apr 29, 2002)

there are no merits I don't think... just I have no more places to tap into!

it functions fine, no problems in boost or anything...


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## 0341TODD (Nov 15, 2003)

Wow, Everyone Is Really Riding My Ass About The Boost Doohickeys Thing Huh? Like I Said I Will Completely Stop With My Sense Of Humor And Stick My Head In My Ass- I Was Just Wondering-- Now Maybe The Problem Is The Wastegate, But If The Car Isnt Moving And Building Constant Pressure And I Was Revving The Engine With The Throttle Body Would I See The Wastegate Move Upon Letting The Throttle Go? Why Couldnt The Wastegate Be Opened Be Opened With The Fpr Vacuum? Does The Boost Solenoid Create That Much More Vacuum? More Then 20 Psi?


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## Zen31ZR (Mar 24, 2004)

0341TODD said:


> Wow, Everyone Is Really Riding My Ass About The Boost Doohickeys Thing Huh? Like I Said I Will Completely Stop With My Sense Of Humor And Stick My Head In My Ass- I Was Just Wondering-- Now Maybe The Problem Is The Wastegate, But If The Car Isnt Moving And Building Constant Pressure And I Was Revving The Engine With The Throttle Body Would I See The Wastegate Move Upon Letting The Throttle Go? Why Couldnt The Wastegate Be Opened Be Opened With The Fpr Vacuum? Does The Boost Solenoid Create That Much More Vacuum? More Then 20 Psi?


Unfortunately , with the engine not under load and mostly stock , you won't see much boost simply revving it up in neutral. Maybe 1 or 2 psi at most. Maybe with an intake AND an exhaust system , it would go higher. If the wastgate was staying closed , you'd see a massive boost spike (if you have a boost guage) above 3000 rpm. Like 20+ psi , and the engine would likely blow. If you're not , don't worry about it , everythings working fine.


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## morepower2 (Apr 19, 2002)

[email protected] said:


> Does it run more psi like that? I'm just confused as to the merits of putting the wastgate line off the FPR.
> And yeah , not only will the wastegate not open , I think the fuel pressure will drop under boost if the FPR line leaks.


Usaualy if you move the wastegate line off of the compressor housing and to a full time manifold vacume sourse, the turbo becomes more snappy as it allows the wastegate to repsond to the boost pressure that the engine is actualy seeing. It seems mickey mouse but usualy you can really feel the SOTP difference.

Mike


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## morepower2 (Apr 19, 2002)

[email protected] said:


> Unfortunately , with the engine not under load and mostly stock , you won't see much boost simply revving it up in neutral. Maybe 1 or 2 psi at most. Maybe with an intake AND an exhaust system , it would go higher. If the wastgate was staying closed , you'd see a massive boost spike (if you have a boost guage) above 3000 rpm. Like 20+ psi , and the engine would likely blow. If you're not , don't worry about it , everythings working fine.


Exactly.

Mike


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## Zen31ZR (Mar 24, 2004)

morepower2 said:


> Usaualy if you move the wastegate line off of the compressor housing and to a full time manifold vacume sourse, the turbo becomes more snappy as it allows the wastegate to repsond to the boost pressure that the engine is actualy seeing. It seems mickey mouse but usualy you can really feel the SOTP difference.
> 
> Mike


Yeah , I thought about doing that , but I'm not real sure which ports up by the mani are full time vacuum and which are thermal actuated (are there any?). Sure would hate to spike at 20 psi before the engine warmed up.


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## morepower2 (Apr 19, 2002)

[email protected] said:


> Yeah , I thought about doing that , but I'm not real sure which ports up by the mani are full time vacuum and which are thermal actuated (are there any?). Sure would hate to spike at 20 psi before the engine warmed up.


Look for ones right on the pleunm and t into them before the thermo valves if any. Check with a vacume gauge to make double sure if you want to.

Mike


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## 0341TODD (Nov 15, 2003)

so the fuel pressure regulator vacuum line would be a good candidate for what youre talking about right Mike?


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## morepower2 (Apr 19, 2002)

0341TODD said:


> so the fuel pressure regulator vacuum line would be a good candidate for what youre talking about right Mike?


It would work right but I don't like dasiy chaining too many things on the FPR because if something springs a leak, the motor could go BOOM.

Mike


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## Zen31ZR (Mar 24, 2004)

morepower2 said:


> It would work right but I don't like dasiy chaining too many things on the FPR because if something springs a leak, the motor could go BOOM.
> 
> Mike


Exactly. I don't think the FPR is a good choice just from the vac line integrity standpoint. The health of the engine depends too highly on the correct fuel pressure , something I'd rather not risk by T-ing lines off of the FPR. 

If nothing else , pull the intake and drill and tap a couple of vacuum ports yourself. It's not horribly hard to do , from what I've seen in the Haynes.


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## 0341TODD (Nov 15, 2003)

Cant I run a vacuum line off the exhaust pipe? HAHAHA-J/K........I will just leave it alone- I agree, I dont think adding all those lines is such a hot idea.


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