I was not getting the boost that I wanted and so I wired my wastegate so it would not open. Sure enough the engine boosted better. My wastegate, like most, is recieves input directly from a line on the turbo, but I have my gauge plugged into the plenum. Between the two is my intercooler which I am sure creates some back pressure. Should I have my wastegate recieving input from the plenum?

quote Originally posted by RotrexFiero: I was not getting the boost that I wanted and so I wired my wastegate so it would not open. Sure enough the engine boosted better. My wastegate, like most, is recieves input directly from a line on the turbo, but I have my gauge plugged into the plenum. Between the two is my intercooler which I am sure creates some back pressure. Should I have my wastegate recieving input from the plenum?

NOT a good idea to wire the wastegate so it won't open unless of course you want to destory you engine. The wastegate should get it's signal from the compressor side of your turbo, that way your dealing with less heat issues.

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still plays with cars..

You should give more information on what type you are using, is it mechanical only or ecm controlled, regardless of which if the wastegate is not capable of opening the way it should to avoid overboost you are taking a big risk. From what you stated there are several reasons you might not be reaching the boost levels you would like. I would connect the line for pressure monitoring to the manifold since that will give you the actual pressure that the engine should be seeing. If your wastegate functions indipendent of the ecm then you need to locate an actuator with an adjustable arm to help increase boost levels or incorporate a small bleed valve with one way flow (check valve) that can be adjusted from inside the vehicle to help delay actuator opening and increase boost. A "T" fitting in the line to the actuator will help accomplish that.

The wastegate is integrated on the turbine side of the turbo. The arm is controlled by a pressure operated actuator with adjustment. I initially had it set to respond to the slightest boost, which I guess it did.

Dont get me wrong, I did not wire it shut and go screaming down the road. I was just curious as to how much of the exhaust was being bleed off. If it is ideally set to open at 6psi, then it surely must start to open, and then fully divert the exhaust energy. Just does not seem very efficient to me. It would seem better to have a electronic solenoid type acutuator, then when it measures 6pso, or whatever, it kicks open all of a sudden.

Anyway, I will play with the arm adjustment and then move to putting a T in the line. Sounds like a good idea.

Get a pressure switch and 2-way solenoid valve, have it so no pressure goes to the wastegate until the pressure reaches the point you set at the pressure switch, then it opens the solenoid and lets pressure go to the wastegate and the wastegate swings open, boost drops and solenoid closes and boost rises. The wastgate will "flutter" and keep the boost at the point you want. This also eliminates boost creep so your turbo spools faster

First off... the Gates line should go BEFORE the throttle body... some where in the pressure piping.

Second if you want boost controll you should get a boost controller, manual are OK but arent great for low pressure applications! If you get an inexpensive boost controller from EBAY that is electronic your better off...

All it does is plug between the sylonoid on the waste gate and the pressure line... allows the pressure into the sylonoid a certain ammount to control boost.

In my 12 second AWD Laser RS i had an Apexi AVC-D boost controller. It allowed wate gate opening at 3 rpm levels 3K, 5K, 7K rpms... Basically it just bypassed the pressure line a certain ammount to atmosphere to allow control.

Again i will say I do NOT trust "manual boost controllers" they are hokey and made from fittings, ball and spring from a hardeware store and FREQUENTLY spike boost pressure. I spiked over 35 lbs once when running 26 on my Laser... they are evil and junk!

ALSO.... you should NEVER EVER EVER EVER play with your boost pressure when you dont have gauges to do so... Air Fuel, BOOST!!, and fuel pressure (and such)
You could be forcing your engine into lean conditions and nuke things

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"Raced That, Wrecked Better" ~In Memory Of Jesse Cesek~ 1980-2000
US Armored Cavalry - Fox 2/81 - Death By 120 - 1 Shot 1 Kill

This has become quite a mystery to me.

First, I recognize the boost control I have is not that trustworthy, but am uncertain at this point if it is limiting boost to the engine. It may be seeing a honest boost psi, but my engine is only seeing a very limited amout of boost.

I do have a boost gauge in the cab, along with a fue//air, and oil temp. I have a adjustable fuel pressure, and a fuel pressure gauge.

Second, does anyone know if the Saab intercoolers can flow enough air for a 3.2 liter engine? I fear that it may be limiting, or gagging the turbo.

I bleed some of the air off the actuator and was able to keep it from opening the wastegate, creating more boost. I got 5psi in second gear. I believe after that the actuator popped the wastegate open.

Any ideas?

quote Originally posted by The Fieromaster: First off... the Gates line should go BEFORE the throttle body... some where in the pressure piping. Second if you want boost controll you should get a boost controller, manual are OK but arent great for low pressure applications! If you get an inexpensive boost controller from EBAY that is electronic your better off... All it does is plug between the sylonoid on the waste gate and the pressure line... allows the pressure into the sylonoid a certain ammount to control boost. In my 12 second AWD Laser RS i had an Apexi AVC-D boost controller. It allowed wate gate opening at 3 rpm levels 3K, 5K, 7K rpms... Basically it just bypassed the pressure line a certain ammount to atmosphere to allow control. Again i will say I do NOT trust "manual boost controllers" they are hokey and made from fittings, ball and spring from a hardeware store and FREQUENTLY spike boost pressure. I spiked over 35 lbs once when running 26 on my Laser... they are evil and junk! ALSO.... you should NEVER EVER EVER EVER play with your boost pressure when you dont have gauges to do so... Air Fuel, BOOST!!, and fuel pressure (and such) You could be forcing your engine into lean conditions and nuke things

The way i posted is almost exactly how high line boost controllers work, except half the price. I did it to my car and it performs just the same as when i put my friends $700 boost controller on it.

Where can you get one, or how do you make one? Sounds like a good solution.

Hook your wastegate to the your plenum. I always tee my gauge and my wastegate from same vacuum port. I then know exacly what the gate is seeing. If you want to control boost, build a cheap manual boost controller. They work fine for all applications and can be built for a few bucks. You are right in that there is some pressure loss through your induction system.

This is how you set it up

You can get the pressure switch at NAPA, (Hobbs pressure switch part# 701-1577)
I got my solenoid valve off a map sensor on a turbo lebaron, technical name is a "Barometric Pressure Read Solenoid"

make sure you have the solenoid vent air from the wastgate line when it takes the pressure off, else it will lock the air in and keep the wastegate open. and also make sure you have a BOV or your turbo can be damaged

Thanks!!!

Great boost controller.

Incidently, I just conducted an experiment. Not necessarily scientific, but I used my shop vac in reverse to flow some air through my mini Saab intercooler. I was not impressed by the output versus the input. Granted my shop vac is pretty powerful, but this intercooler is not so efficient as I initally thought. Any idea what this thing will handle?
Any specs? Anyone?

Thanks for all the help, you guys are great!

post a picture, i have a 15x9 on my 2.2 liter

Dont know how small that saab IC is but i would try a Stock front intecooler from a Eclipse/Talon/Laser... They may flow more.

The stock setup for you controller just opens the waste gate MORE as you make more boost... this is a perfectly OK system if you only want to run a certain amount of boost... That which is produced with waste gate fully opened...

However some larger turbos... like that which was on my Laser could flow way MORE with the waste gate fully open then you would want... 16PSI or so. Thats why it all comes down to output and consumption.

You need to get a boost gauge, hook it up and then you can figure out what you need to do for your controller... stock 2.8L i wouldnt run much over 5-8 psi. Which could be all your outputting with the waste gate fully open (rpm depending)

REASON NOT TO PLUMB THE LINE TO THE MANIFOLD...

When you let off throttle you basically then pull vacuum through that line, when you DO THIS you are then pumping all the exhaust through the turbo making it create boost against the throttle body and out the BOV. When you open the throttle you then dump tons of boosted air into the engine and you WILL over boost!!!

The boost line NEEDS to go like this...

the wastegate regulates exhaust air to control the turbine, when the throttle closes it will put out alot less exhaust gases so the turbine will slow down even though the wastgate isnt open. It will not overboost because the turbine will not be spinning past the point that it did to make the boost set by the pressure switch, during shifting you will start back at a lower RPM so if the turbo stayed at the same speed then yes it would overboost briefly, but since the turbo will slow way down during shifting and the lower RPMs will not be able to sustain the turbo to make the overboost you will not overboost.

I have this setup with the line going to my manifold and i have never overboosted

quote Originally posted by The Fieromaster: REASON NOT TO PLUMB THE LINE TO THE MANIFOLD... When you let off throttle you basically then pull vacuum through that line, when you DO THIS you are then pumping all the exhaust through the turbo making it create boost against the throttle body and out the BOV. When you open the throttle you then dump tons of boosted air into the engine and you WILL over boost!!! [/IMG]

I'm afraid this is not correct. When you pull the vacuum on the gate signal line, it will shut the gate shut and run the exhaust through the turbine that is true. However, you want that as the case as you will respool much faster. What your senario doesn't consider is the fact that exhaust flow will fall off instantly and significantly when you close the throttle. Your blow off valve will dump boost pressure in the line which will prevent any possibility of a boost spike due to excess pressure in the induction track.

If you have a turbo car with your gate plumbed before the TB, try moving it after. You will find no problems with boost spikes and your car will spool faster. This is especially true if you are running an excessively large turbo.

a little late in the game but the only time you would want to plumb the wastegate pressure line to before the throttle body would be if you have no blow off or bypass valve -- those are you safety system to prevent overpressuring the intake system and damaging the compressor...

with a BOV in the intake line you want ot plumb the wastegate to the plenum - I have the guage,bov, and wastegate all on the same port so they all see exactly the same thing

I talked with a mechanic friend who told me that it is possible that I may be blowing too much exhaust energy, too fast, and that I may have to restrict the exhaust some to slow the flow. He actually suggested a muffler. I am running, if I remember correctly, 1.5 inch turbo manifold. Is this possible? He suggested this after I told him that the turbo is boosting if first gear but no psi is registering on the guage. He also said I may be spooling so quickly that I am kicking open the wastegate.

I highly doubt if that's the case. If it were, you would have such an exhaust overpressure that you would have boost creep. What the cause is, and I would bet money on this, is your gate is seeing the pressure of the signal port on the turbo itself and opening. However, your induction system is a little lossy. The pressure drop across an induction system is quite linear. If you plug that port and run your gate from the manifold, that will solve your problem!

There are other things that can keep the boost down,specifically in the higher gears.What is your fuel pressure set at,and how did you set it?What size are your injectors?Does your computer go to open loop with the gas pedal floored?If your fuel pressure is too high it will cool your exhaust and drop boost pressure,just like the other examples I mentioned.In my GN I set the fuel pressure at 35lbs above atmosphere at zero atmosphere.

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#1112
Question my ability,question my intelligence,never question my integrity!

Well, I plugged my boost gauge into my turbo, instead of the manifold. The turbo is make good boost, registered 5 psi with little rpm effort. So if you have been following this thread I most definitely have a intercooler that is stiffling air flow to the manifold. The question is, is it a bad IC or just too small for the engine?

I know others have run the Saab IC so are you running very low boost levels with it, which would not make sense since you could easily run 6psi without it. I fitted the car with the Saab intercooler so I could run around 10-12 psi with some cooling.

Could the IC be clogged somehow? Anyone know anything or used the Saab IC before?

I guess it's possible that the IC is clogged. I've got a Saab IC on the system and it has no problem making boost to 15psi. The key to getting the boost that you want is to hook your wastegate to your manifold along with your boost gauge. Plug the port on your turbo. Do that and your problem will be solved.

quote Originally posted by caddyrocket: I'm afraid this is not correct. When you pull the vacuum on the gate signal line, it will shut the gate shut and run the exhaust through the turbine that is true. However, you want that as the case as you will respool much faster. What your senario doesn't consider is the fact that exhaust flow will fall off instantly and significantly when you close the throttle. Your blow off valve will dump boost pressure in the line which will prevent any possibility of a boost spike due to excess pressure in the induction track. If you have a turbo car with your gate plumbed before the TB, try moving it after. You will find no problems with boost spikes and your car will spool faster. This is especially true if you are running an excessively large turbo.

Actually if your running any kind of larger turbo as i did in my laser YOUR wrong... There is even new boost controllers that keep the waste gate OPEN from idle RPM to a certain RPM to allow then engine to bypass the restriction that IS the turbo. This in turn allows the engine sharper low end throttle response. When the set RPM is reached the waste gate slams shut diverting the flow through the turbo spooling it up almost instantanious...

But i guess i dont know anything because i didnt have a worthless 4 banger Laser that only ran 12 at the track

Here it is in black n white, the waste gate on the boost side of system..

OR coppied out of Apexi manual...

OR what i copied from Apexi AVC R manual...

all have line to waste gate from CHARGE pipe not the manifold... and are inturpted or atmsohpere vented at the boost control sylonoid

[This message has been edited by The Fieromaster (edited 09-13-2005).]

quote Originally posted by The Fieromaster: Actually if your running any kind of larger turbo as i did in my laser YOUR wrong... There is even new boost controllers that keep the waste gate OPEN from idle RPM to a certain RPM to allow then engine to bypass the restriction that IS the turbo. This in turn allows the engine sharper low end throttle response. When the set RPM is reached the waste gate slams shut diverting the flow through the turbo spooling it up almost instantanious...

Yes it completely makes sense that a turbo would spool faster by not using your exhaust energy and keeping the shaft speed low until you want to spool it. It definately makes sense that the fastest way to get something to spin 70,000 rpm is to start it from 1,200rpm rather than 15,000. This is kind of like cold water boiling faster than warm water. Or perhap perpetual motion.

So what you are trying to say above is by slowing spool time to let the engine "breath" better by keeping the gate open is going to help low end response? Then "Slam" the wastegate shut to instantly divert this additional energy to the turbine to spool it. Sounds logical to me. All N/A engines make more horsepower down low than the same engine would if in a boosted condition.

Here are the problems with your theory:
Boost increase exponentially. This means as the turbo spools it crams more air into the cylinders. This condition is called boost. Adding more fuel to remain soich, you create more exhaust flow. That greater exhaust energy (mass and volocity) acts to exert greater pressure on the turbine, hense spooling it faster or adding more boost. Keeping the gate open prevents the turbo from spooling up. All "slamming" it shut does is place added stress on your shaft and turbine and slows your spool time down.

quote But i guess i dont know anything because i didnt have a worthless 4 banger Laser that only ran 12 at the track

Wow 12 whole seconds eh? Man yo

u must be using a a 101mm AND nitrous to run a 12 with a 4 banger!! NOONE is doing that.. Er perhaps not... Here is my list of recent accolades..

95 Civic Hatchback (D16Z6 ) - 11.3@119
97 Camaro Z28 (Stock engine, street tires. 2.3 60') - 11.8@128
554hp/630tq (stock LT1 turbocharger system built by, you guessed.. me)
01 Grand Prix GT (Nonsupercharged L36) - 12.8@114
325hp/370tq (stock l36, stock 4T60e NON-intercooled)
438hp/429tq (same as above with a 50 shot of nitrous)
01 Firebird V6 (stock engine L36) - 13.3
352hp/416tq (Stock engine, Intercooled)
94 Firebird V6 (Stock bottem end. Ported heads)
336hp/397tq
99 TransAm LS1 (Stock engine)
615hp/613tq
And the list goes on...

quote Here it is in black n white, the waste gate on the boost side of system.. http://www.ecanfix.com/users/mdhamilton/images/vacuum/vacuumt.jpg OR coppied out of Apexi manual... http://www.jull.co.uk/mods/images/vacuum_hoses.jpg OR what i copied from Apexi AVC R manual... https://images.fiero.nl/pffimages/boostsetup.JPG all have line to waste gate from CHARGE pipe not the manifold... and are inturpted or atmsohpere vented at the boost control sylonoid

Thanks for quote Apexi's specific installation instructions for some car. Here is another helpful link that might better explain why keeping the gate closed and the shaft speed up is beneficial to horsepower.

http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html

Here is another manufacturer that claims doing it his way is best... This might be your ticket into the 11s.

http://www.turbonator.com/

I guess if you are looking for a case study, both fiero turbo systems I've built are getting full boost by ~2krpm.. To your previous point, I guess I don't know what I'm talking about either...

At the end of the day, it goes like this.. You hook that bad boy up any way you like. I'll hook it up to the manifold, get spooled up quickly and get on down the track....

[This message has been edited by caddyrocket (edited 09-14-2005).]

Yea, if you look at the wastegate bypass hole in most turbos, its really the side of a quarter if that, you're not going to reduce any real amount of back pressure by opening it, its just enough to keep the turbine speeds in check.

Sorry I did not mean to create such a heated discussion. Lets just keep in healthy, but I am surprised that Dennis has not jumped in here somewhere. I am sure he is monitoring this.

Anyway, I removed my Saab intercooler tonight, and feeling rather silly removed a paper towel form the inside. Yes, it was clogged. I only road tested the car briefly but it was boosting much better. Imagine that.

But, I am still interested, and in need of a efficient boost controller. So I watch and learn. I appreciate all the discussion, ideas, and suggestions.

Naaa, I should have restrained myself. Sorry about that. Paper towl eh? Love those oppses lol. Glad to hear that it is running better. Just for the sake of arguement, try hooking the wastegate to the vacuum port by your distributor.

I've now built two unique turbocharger systems for Fieros and they both pull full boost by 2k. There are a lot of design aspects contributing to that fact, but you will most likely find a little harder hitting spool up if you have the gate plumbed in before the tb. Anyway, good luck with it!

quote Originally posted by The Fieromaster:

if you look at that diagram - the line going to the solenoid may be coming from the charge pipe - but the sensor that controls the solenoid is coming from the plenum -- therefore you can determine that without an electronic controled wastegate that setup should have the vac line going to the plenum

edit - infact all those are specificly for electronics systems - which all require a pressure sensor - often being the stock MAP sensor which oddly enough is attached to the plenum..

the pressure that you want controlling the wastegate is the plenum pressure - an electronic system may pull its pressure line from the chargepipe but its still being controlled by plenum pressure

[This message has been edited by Kohburn (edited 09-15-2005).]