wastegate loop performance upgrade.. ?

Started by ZachS, August 16, 2002, 07:06:19 PM

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ZachS

Hey guys...

I cant really remember who brought this entire deal up, but I remember the person recieving some flack for the entire thing.

I was just curious what was done to 'loop the wastegate?'  What, exactly, do you have to do?  I understand that the raised boost levels could definately cause some concerns, but I was just curious for my own information on what exactly needed to be done.

Thanks in advance!  :)

later,
Zach

GPChief

1st Off neither TGPilot or myself will take any responsibility for what YOU do to your car.  Remember that we are at 5000 Ft + above sea level with much different oxygen at this altitude.  Doing this to your car a sea level will have bad effects (blown motor like others have experienced). :twisted:

The simple mod is to take off the vacuume line that goes to the waste gate and plug it.  With doing this the waste gate is held open all the time meaning full boost all the time. :wink:

Once again this will blow an engine at sea level real quick!!  TGPilot & I will not be responsible. :twisted:  :bad-words:  :nono:  

If you ask nicely maybe someone will talk about the "threaded wastegate" or better yet - research it on the web.  :roll:
2004 GTP -  3.8 Blown - Only modding for MPG.
1997 GTP  - 3.8 Blown - Too many mods to list.
1996 GTP - 3.4 DOHC - Twin to my 1997.
1995 SE - soon to be a 3.8 turbo car.
1990 TSTE x 2 white cloth
1990 TSTE x 1 maroon leather
1990 TGP - 5 speed.

ZachS

Hey Twalt...

Yeah... I figured it would blow an engine at sea level.  I'm not quite that dumb  :wink:

But some guys from work were saying that they've heard of it being done, and I remembered that somebody explained it on here, so I was just curious.

Thanks for the info.  :)

later,
Zach

GPChief

It was a "painfull blow to the obvious" when TGPilot told me about it. :D
2004 GTP -  3.8 Blown - Only modding for MPG.
1997 GTP  - 3.8 Blown - Too many mods to list.
1996 GTP - 3.4 DOHC - Twin to my 1997.
1995 SE - soon to be a 3.8 turbo car.
1990 TSTE x 2 white cloth
1990 TSTE x 1 maroon leather
1990 TGP - 5 speed.

Chris A

The only reason this works on the TGP is that the wastegate spring is very weak. It only holds about 4 pounds of boost. When you undo the wastegate vacuum connection its the exhaust that blows the wastegate open and its "regulated" that way. If you have a chip, or no boost cutoff, then  its an easy way to get more boost, but it is VERY dangerous. My brothers car has been running this way for a while since his boost solenoid won't work and we can't figure out why. So the only way for him to have any boost is to undo the line. We are in MD so it hasn't blown it yet, but it will hit about 15 psi of boost. Now, does the extra boost make it faster? who knows. the timing could be backed off enough to negate the extra boost.

Now as far as a threaded wastegate, it allows you to preload the actuator so it won't open as SOON, but still opens at the same rate. So by moving the opening pressure up, you move the total pressure up. Other turbo's use a much heavier actuator that doesn't open at a very fast rate. They kinda have to be matched, but I coudn't tell you what the relationship should be.

Chris

skalor

wouldn't a stardard mechanical boost controler in line with a the stock wastegate controller negate the same outcome.  Most of my friends with turbos make a ball valve with parts from home depot and I don't see why you couldn't just put the ball valve between the wastegate controller and the actuator.
'90 Lumina <-- Turbo 3.1 - SOLD :P
'89 TGP <-- getrag 284 equipped - SOLD :(
'89 Olds Cutlass Ciera International coupe

florida_tgp

You can do that, I did. There are a lot of ball and spring boost controllers on ebay, I just installed one of those, replaced my simple bleeder valve. Works fine. I still have factory boost limit of 9.5lbs.
I guess I could a fiddled around with parts from home depot, but i wasn't in the inventive mode, let somebody else find spring size, bleed hole size, etc.
I just like the foot control  of my boost , instead of computer controller. By the way, if any body else is using a similar setup, tell me if you have windows up, radio off, a funny hissing sound at part throttle any time you  have  boost, even 1 or 2 lbs. I think it is the turbo builting to 9 or so lbs boost, and air rushing past partially cracked
throttle.
white Turbo STE

Chris A

Quote from: florida_tgpYou can do that, I did. There are a lot of ball and spring boost controllers on ebay, I just installed one of those, replaced my simple bleeder valve. Works fine. I still have factory boost limit of 9.5lbs.
I guess I could a fiddled around with parts from home depot, but i wasn't in the inventive mode, let somebody else find spring size, bleed hole size, etc.
I just like the foot control  of my boost , instead of computer controller. By the way, if any body else is using a similar setup, tell me if you have windows up, radio off, a funny hissing sound at part throttle any time you  have  boost, even 1 or 2 lbs. I think it is the turbo builting to 9 or so lbs boost, and air rushing past partially cracked
throttle.

You mean the not really building  boost sound? yeah, my brothers car does that. It sounds like air is leaking, but not really like the turbo is building boost. I don't know if its the TB making the noise, or just the way the turbo sounds.

Chris

Tooky

My TGP is stock with a K&N cone on the turbo, and I noticed on the factory boost gauge, the turbo noise starts very whooshy around -5" vacuum and then once it hits 1-2 PSI, the noise stops completely and changes into a very high pitched whistle.  But if you drive in such a manner to maintain that 1-2 PSI range, it's loud and sounds like a tire leaking.
Josh Straub
1990 Pontiac Turbo Grand Prix, GT2871R 475HP-capacity turbo, built 4T60, 28# Injectors, DIY Ostrich realtime chip tune, JeffM Crossover, Cold A/C, BoostValve.com manual controller @ 14 PSI.  200,000 mi factory original motor.  Best time on T25 @ 11 PSI: 14.78 @ 93 MPH.
1991 GMC Syclone: 11.79 @ 114 MPH. Stock with PT51 turbo plus SMC alcohol injection and tuning, 24 PSI

skalor

From what it sounds like my car makes the same noise.  If I get on it pretty good and then let off a little but still on the gas it screams really loud.  I also contributed it to the throttle body only being partially open.
'90 Lumina <-- Turbo 3.1 - SOLD :P
'89 TGP <-- getrag 284 equipped - SOLD :(
'89 Olds Cutlass Ciera International coupe

1trucavalier

Chris A! what part of md?  i am in alexandria, va and if possible i could let someone with a TGP knowledge (never again the idiotic dealer) look at my TGP and see wtf is going on with it.  If you aren't to busy.  TY!
hi-flow intake, straight pipe, dsm bov, 24lb inj,  polished upper intake, turbo, and frt valve cover.

Chris A

Quote from: 1trucavalierChris A! what part of md?  i am in alexandria, va and if possible i could let someone with a TGP knowledge (never again the idiotic dealer) look at my TGP and see wtf is going on with it.  If you aren't to busy.  TY!

Well, I'm busy, but would LOVE to  meet up with another TGPer. There are/were a few guys around here who had cars but I never was able to catch up with any of them (despite alot of chasing). There is one other local guy who bought a TGP after I met him, but I don't see much of him. I work in laurel, so your not terribly far. We have guys that live as far as sterling (i think) and down past waldorf and SoMD who come to our shop for GN/TType repairs. I usually hang out on the weekend with some exceptions so you could come on by then too!

Chris

1trucavalier

I tried that mod monday and the turbo spools faster but I had to switch it back.  My car isn't running 100% and I don't want to damage it.
hi-flow intake, straight pipe, dsm bov, 24lb inj,  polished upper intake, turbo, and frt valve cover.

TGPilot

Which mod? Disconnecting the waste-gate loop? Be careful... 8)

1trucavalier

yeah the waistegate mod.  I didn't floor it.  I did just enough to make it boost then let it off.  My car isn't running right so I won't dare floor it past the stock 9.5.  The turbo does though spool to max a whole lot quicker.  I already switched it back.
hi-flow intake, straight pipe, dsm bov, 24lb inj,  polished upper intake, turbo, and frt valve cover.