scottyMIz Posted July 6, 2001 Share Posted July 6, 2001 I got it all done the guys at the muffler shop did a great job bending the pipe.I had to fit everything at home and get it all together checked for leaks seems like there isn't any but now in first it only goes to about 7 psi and then in second it only goes to 8 psi it use to run 9 psi in second and 8 in first.Could it be the intercooler?Or the piping?I can't turn up the boost yet cuz i don't have an adjustable pop off valve.Would it make that much difference if i put in a blow off valve?I plan to anyway but i was just wondering why it doesn't go up as high in first and second. Quote Link to comment Share on other sites More sharing options...
Drax240z Posted July 7, 2001 Share Posted July 7, 2001 The extra volume you've added in the intake system (ie the intercooler) is causing a pressure drop. The better the IC you get, the less the pressure drop will be. (normally) Usually you can simply turn up the boost a little to compensate for the drop. Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 7, 2001 Share Posted July 7, 2001 Where is the pressure reference to your wastegate connected to? My guess is that you have it connected between the turbo and the intercooler. If you move it to between the intercooler and the throttle, the pressure drop across the intercooler will get taken into account, and you should get your old boost pressures back. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted July 7, 2001 Share Posted July 7, 2001 I think Tim nailed this one! The beauty of turbos is that they compensate via the wastegate for things like changes in elevation or moreless restriction in the intake. Quote Link to comment Share on other sites More sharing options...
scottyMIz Posted July 7, 2001 Author Share Posted July 7, 2001 Thanks guys it runs like a bat out of hell now i have the gauge hooked in the intake.It feels quicker to me seems to not take as long to spool up.Hey guys how do you post pics on here?I'll show the ic and piping i know it's doing it's job cuz if i touch the piping before the ic and after there is a huge diff in temp even if i try on the intake side on the ic and the out of it i get the same results.I don't know how effecent it is but it does work really well. Quote Link to comment Share on other sites More sharing options...
scottyMIz Posted July 7, 2001 Author Share Posted July 7, 2001 i see what your saying now sorry it was a long night.So you want me to take the pressure line off the turbo for the wastegate and move it to the pipe between the ic and throttle? Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 7, 2001 Share Posted July 7, 2001 im really interested in seeing how badly the crimps are. I really was going to get my piping crimp bent, but i had my exhaust done that way and the crimps are just horrible. A ruff guesstimate is around a 40% airflow loss, and it wasnt even on like a 90 degree bend. Maybe a competant shop will do it better. Also, scottie, how did you run your i/c pipes and what i/c. I havnt been following anyone on the forum lately, i just got my computer working after a few weeks of downtime. Thanks Scott Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 7, 2001 Share Posted July 7, 2001 quote: Originally posted by scottyMiz: i see what your saying now sorry it was a long night.So you want me to take the pressure line off the turbo for the wastegate and move it to the pipe between the ic and throttle? Yes, that's correct. The wastegate will regulate the turbo output to x psi at whatever reference point you give it. So, if the wastegate pressure line is connected between the turbo and the IC, and your wastegate is set for, say 9psi, the boost pressure between the turbo and the intercooler will be 9psi. But, whatever drop you have across the intercooler will not be accounted for, and your actual boost pressure will be 9psi minus whatever drop you have across the IC. If you move the reference point to between the IC and the throttle body, the boost pressure AFTER the IC will be regulated to 9psi (or whatever your wastegate is set to). Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted July 8, 2001 Share Posted July 8, 2001 Scott, I used the NPR in my L28T. Look here: http://www.zdriver.com/members/scottiegnz/icmods.html Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 8, 2001 Share Posted July 8, 2001 Timz, i have a question for you. You said move the reference point on the wastegate to after the intercooler. I am a bit confused on how the wastegate works now. I have my reference point on my wastegate connected to the little nipple on the turbo inlet. I am thinking this is a vacuum source only, as the turbo is sucking all the air from the point to the airfilter. Moving the reference line to the manifold would have the wastegate actuator seeing boost, is this how it is suppose to work? When i had my intercooler hooked up, i was getting REALLY bad boost pressure problems. I was getting like 7 psi in first gear, 11 in 2nd, and 16 in third, and higher in 4th. But I could adjust it so i could have like 14 psi in first gear, but it would skyrocket in second. could the fact that i have the wastegate tubed wrong be causing this. I have a t3/t4 turbo but the stock wastegate. Thanks Scott Quote Link to comment Share on other sites More sharing options...
scottyMIz Posted July 8, 2001 Author Share Posted July 8, 2001 het tim i have a dial a boost on it and i run it wide open cuz the pop off valve releases the rest would i still have to move the feed line for wastegate? Quote Link to comment Share on other sites More sharing options...
Drax240z Posted July 8, 2001 Share Posted July 8, 2001 Dude, absolutely that could be causing your problems! Basically the wastegate opens at a set pressure, in the stock case its 6-7psi. It uses the vacuum line to trigger it. If you have it hooked up right at the turbo outlet, which is how it it stock, the 6-7psi is what is right at the turbo outlet. Once you add an intercooler and have a pressure drop, your wastegate may be seeing 6-7psi, but instead of your engine actually seeing 6-7psi in the manifold, its likely more like 4-5psi. (Assuming a 2psi pressure drop across the IC) So technically with no other mods, you may be losing power by adding an intercooler. (granted the higher air density could offset this somewhat, but thats another point all together) Now, by connecting the vacuum reference line to the turbo inlet, your wastegate will NEVER see the 6-7psi that it is designed to open at. It will only see vacuum. Therefore your wastegate will NEVER open. Which sounds like exactly the symtoms you describe. Do yourself a favor, and if you are running an intercooler, reference the wastegate from between the IC and the throttle body. Then your engine will be seeing the same pressure of air after the IC install than it did before. [ July 08, 2001: Message edited by: Drax240z ] Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted July 8, 2001 Share Posted July 8, 2001 Scotty, if you are running a t3/t04, then you should be using an adjustable wastegate rod so you can up the boost to recover the boost lost from the pressure drop in the I/C and take advantage of that bigger turbo. IMO, it really does not matter whether the source for the wastegate is coming from the compressor or the intake. What is important is that the reference point for the boost gauge comes from the intake. MOF, I think you get a more consistent source for the wastegate from the compressor and if the rod is adjustable, you adjust the boost accordingly until the gauge tells you that you are getting the desired boost at the intake. I had a similar problem with my L28T and it ended up being the ID of the line that caused the problem. BTW, the Buicks have the wastegate source off the compressor with a restrictor in the line. Think carefully about what is actually happening. Boost pushes against a diaphragm in the cannister which pulls the rod away from the turbo, pulling the lever which opens the wastegate puck. The less the puck opens, the less boost gets bled off, the more boost will be produced. With the source at the compressor, the diaphragm should be seeing higher boost making it easier to open the puck. Instead, as you put more load on the engine in the upper gears, the boost keeps going up which means the puck is not opening as much as it should. To me that means 1 of 3 things. - There is a restriction in the source line - The diaphragm is bad - The wastegate puck is stuck and not swinging open freely. Disconnect the wastegate rod and make sure the puck moves the puck freely. Every serious turbo owner should own a MityVac. If you had one, you would connect it to the wastegate and pump it up and as it increases the pressure (like boost) you should see the wastegate rod get pulled into the cannister. If it does not, then the diaphragm is probably torn. If the those are OK, check the source line and then try different ID lines. Vacuum lines are cheap. BTW, any boost testing should be done in 3rd because it puts more load on the engine and you have more time to react if the boost goes off the scale. [ July 08, 2001: Message edited by: Scottie-GNZ ] Quote Link to comment Share on other sites More sharing options...
scottyMIz Posted July 8, 2001 Author Share Posted July 8, 2001 Hey ferrari did you get the pics i sent you?What did you think?I sent them to your email that was posted on here.I'm going to try to move the waste gate feed line today. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted July 9, 2001 Share Posted July 9, 2001 Waste gate should be reading manifold pressure, not anything in the piping leading from the turbo.... Quote Link to comment Share on other sites More sharing options...
Drax240z Posted July 9, 2001 Share Posted July 9, 2001 quote: Originally posted by Z_Ferrari: I have my reference point on my wastegate connected to the little nipple on the turbo inlet. I am thinking this is a vacuum source only, as the turbo is sucking all the air from the point to the airfilter. What I got out of that is that the vacuum reference is hooked up before the turbo inlet, so that it will never see boost, and that the wastegate will never open. Did I misread it? Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 9, 2001 Share Posted July 9, 2001 quote: Originally posted by BLKMGK: Waste gate should be reading manifold pressure, not anything in the piping leading from the turbo.... Looks like this has been pretty much beaten down, already... It doesn't absolutely have to be manifold pressure - the wastegate actuator has no use for the vaccuum part of the signal, it just cares about boost pressure. As long as the reference is after the intercooler, it should work fine. For the external wastegates that I have seen, the boost pressure side of the diaphragm is the side that the valve is on, meaning that the valve seal is also there. In my experience, the wastegate valve seals are kind of leaky, and I'd prefer not to send it a vacuum signal if I can avoid it. Vacuum leaks, sucking crap into the diaphragm, etc. The internal gates on the T3 turbos are a regular dashpot, so this probably isn't a concern there. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 10, 2001 Share Posted July 10, 2001 the wastegate actuator vacuum line i have is hooked up to the turbo inlet. So...its seeing NO boost, but its still functioning fine. How is this happeneing? Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 10, 2001 Share Posted July 10, 2001 quote: Originally posted by Scottie-GNZ: Scotty, if you are running a t3/t04, then you should be using an adjustable wastegate rod so you can up the boost to recover the boost lost from the pressure drop in the I/C and take advantage of that bigger turbo. IMO, it really does not matter whether the source for the wastegate is coming from the compressor or the intake. What is important is that the reference point for the boost gauge comes from the intake. MOF, I think you get a more consistent source for the wastegate from the compressor and if the rod is adjustable, you adjust the boost accordingly until the gauge tells you that you are getting the desired boost at the intake. I had a similar problem with my L28T and it ended up being the ID of the line that caused the problem. [ July 08, 2001: Message edited by: Scottie-GNZ ] Ok, i thought that might be the problem too. My i/c lines were only 1 1/2", i/d. my i/c inlet/outlets are only 1 7/8" OD, so those are really small, and i went with that size the whole way. Is this going to be my fatal problem? do i need to get a bigger i/c with larger inlet and outlet tubes? I also have a question with the threaded wastegate rod. I can sorten it so the boost increases, BUT only to a certain point, around 10 psi. Then the actuator arm just becomes incredibly hard and trying to get it on the puck arm is very hard. Should i just brute force it? Thanks scottie Scott Quote Link to comment Share on other sites More sharing options...
scottyMIz Posted July 10, 2001 Author Share Posted July 10, 2001 hey scott what they are saying it the acuator only works on boost when your turbo spools up it puts out boost and pushes the acuator diaphram and opens the wastegate.They are suggesting moving it inbetween the ic and throttle butterfly so it sees the pressure it needs up there to keep the boost constant in every gear.I'm going to do it soon. Quote Link to comment Share on other sites More sharing options...
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