IWG not giving me desired boost
#21
Elite Member
iTrader: (4)
Join Date: Aug 2009
Location: Redwood City, CA
Posts: 1,784
Total Cats: 42
i dont see how this would be a problem... ive ran them both ways without issue... the upside to connecting the wastegate to manifold pressure instead of pre throttle body pressure is so you can compensate for a crappy low flowing intercooler that creates a pressure drop. making the wg open at a specified manifold pressure and not the higher pressure seen on the turbo side of a poor flowing ic.
just my $.02
just my $.02
All intercoolers create a pressure drop. Not "crappy low flowing" ones.
#22
i dont see how this would be a problem... ive ran them both ways without issue... the upside to connecting the wastegate to manifold pressure instead of pre throttle body pressure is so you can compensate for a crappy low flowing intercooler that creates a pressure drop. making the wg open at a specified manifold pressure and not the higher pressure seen on the turbo side of a poor flowing ic.
just my $.02
just my $.02
If you want to avoid the "poor flowing ic" connect the source right between the IC and the TB, not in the intake manifold.
#23
first, fix your wastegate can. It is a problem and will continue to be a problem, regardless of how the rest of your drivetrain is setup. Make it straight.
Second, yes, your 3" exhaust can affect boost, *BUT*, it will only be due to boost creep, and if that was the problem, you'll probably only ever see creep beyond 5k+ rpms anyways. The only good solution to boost creep is to have your wastegate ported professionally. I tried having a wastegate ported by a machinist, he did a good job with what he did, but he didn't have a thorough understanding of what needed to be done, the problem was only marginally better afterwards, but still nowhere near fixed.
Third, wastegate signal needs to be sourced somewhere before the throttle body. It's not a BPV. Sourcing your wastegate after the TB is going to turn your throttle into an on/off switch instead of a smooth controllable throttle.
Second, yes, your 3" exhaust can affect boost, *BUT*, it will only be due to boost creep, and if that was the problem, you'll probably only ever see creep beyond 5k+ rpms anyways. The only good solution to boost creep is to have your wastegate ported professionally. I tried having a wastegate ported by a machinist, he did a good job with what he did, but he didn't have a thorough understanding of what needed to be done, the problem was only marginally better afterwards, but still nowhere near fixed.
Third, wastegate signal needs to be sourced somewhere before the throttle body. It's not a BPV. Sourcing your wastegate after the TB is going to turn your throttle into an on/off switch instead of a smooth controllable throttle.
#26
Junior Member
Thread Starter
iTrader: (1)
Join Date: Jun 2009
Location: Los Angeles, California
Posts: 176
Total Cats: 0
1. Okay, I know the function of the wastegate, but I dont understand how to control it. Does shortening or lengthening the rod increase and decrease the boost (PSI)? Or, does it just help with spool?
The wastegate I have, the cracking pressure around 10 PSI. Is there anyway I can get this wastegate to run at 7-8 PSI?
2. Lets say my wastegate is rated at 7 PSI from the factory, is there anything I can use/change to make the wastegate run any lower PSI, or would 7 PSI be the lowest PSI I can run at.
3. Can I shorten my rod by adjusting it all the way to the limit? And, would I shorten rod all the way and then mount it or should I mount the wastegate first and then adjust the rod?
4. Can a MBC be used to lower the PSI below what the wastegate is rated at?
Sorry if I don't make any sense.
The wastegate I have, the cracking pressure around 10 PSI. Is there anyway I can get this wastegate to run at 7-8 PSI?
2. Lets say my wastegate is rated at 7 PSI from the factory, is there anything I can use/change to make the wastegate run any lower PSI, or would 7 PSI be the lowest PSI I can run at.
3. Can I shorten my rod by adjusting it all the way to the limit? And, would I shorten rod all the way and then mount it or should I mount the wastegate first and then adjust the rod?
4. Can a MBC be used to lower the PSI below what the wastegate is rated at?
Sorry if I don't make any sense.
#27
Junior Member
Thread Starter
iTrader: (1)
Join Date: Jun 2009
Location: Los Angeles, California
Posts: 176
Total Cats: 0
Would buying this item below and running it with a MBC solve all my problems?
http://cgi.ebay.com/ebaymotors/T25-T...#ht_1910wt_793
http://cgi.ebay.com/ebaymotors/T25-T...#ht_1910wt_793
#29
What I have seen people do is cut the rod, thread it, and have an adjusting nut for longer or shorter settings.
Picture is from this thread, diy adjustable wg
If you want more boost put some washers where the wastergate is bolted on, between the compressor and wg plate.
Picture is from this thread, diy adjustable wg
If you want more boost put some washers where the wastergate is bolted on, between the compressor and wg plate.
#30
Junior Member
Thread Starter
iTrader: (1)
Join Date: Jun 2009
Location: Los Angeles, California
Posts: 176
Total Cats: 0
@Hustler , I have no idea what that is
@mazpr , Will shorter settings allow me to run at a lower boost (7PSI) if the wastegate is originally rated 10PSI from the factory? Should I use more preload?
@mazpr , Will shorter settings allow me to run at a lower boost (7PSI) if the wastegate is originally rated 10PSI from the factory? Should I use more preload?
#32
Junior Member
Thread Starter
iTrader: (1)
Join Date: Jun 2009
Location: Los Angeles, California
Posts: 176
Total Cats: 0
God, I am so confused. When people use the term "short rod", does that mean to adjust the length shorter and then mount it,
or
does it mean mount the wastegate, adjust length of rod (now the hole of the rod won't reach the shaft that opens the wastegate), and then apply preload?
or
does it mean mount the wastegate, adjust length of rod (now the hole of the rod won't reach the shaft that opens the wastegate), and then apply preload?
#33
Tour de Franzia
iTrader: (6)
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,085
Total Cats: 375
1. Okay, I know the function of the wastegate, but I dont understand how to control it. Does shortening or lengthening the rod increase and decrease the boost (PSI)? Or, does it just help with spool?
The wastegate I have, the cracking pressure around 10 PSI. Is there anyway I can get this wastegate to run at 7-8 PSI?
The wastegate I have, the cracking pressure around 10 PSI. Is there anyway I can get this wastegate to run at 7-8 PSI?
Bolt the can then pull the rod to the eyelet on the flapper mechanism.
No.
#34
Junior Member
Thread Starter
iTrader: (1)
Join Date: Jun 2009
Location: Los Angeles, California
Posts: 176
Total Cats: 0
Thanks Hustler
How do I make the rod longer? Do I mount the wastegate first and then adjust the length? But in this case, the rod won't fit on the eyelet on the flapper mechanism?
Or, should i just elongate the rod as far as possible, and then mount the wastegate?
If the wastegate I have cracks at 10 PSI, is there any way I can check that the wastegate will be at 7psi when i elongate the rod?
How do I make the rod longer? Do I mount the wastegate first and then adjust the length? But in this case, the rod won't fit on the eyelet on the flapper mechanism?
Or, should i just elongate the rod as far as possible, and then mount the wastegate?
If the wastegate I have cracks at 10 PSI, is there any way I can check that the wastegate will be at 7psi when i elongate the rod?
#36
Junior Member
Thread Starter
iTrader: (1)
Join Date: Jun 2009
Location: Los Angeles, California
Posts: 176
Total Cats: 0
but if i adjust the threaded coupler, which will increase the length of rod, the hole on the rod won't fit on the eyelet on the flapper mechanism.
I know then if shortening the rod, I can apply preload, but if I lengthen the rod, how do I make it work?
I know then if shortening the rod, I can apply preload, but if I lengthen the rod, how do I make it work?
#37
There should be a lot of preload already. By loosening it there should be less preload.
Basically if you run it once without connecting the rod to the arm, your waste gate will be fully open the entire time, in other words you will have lots of lag and very little boost. Take it to redline and keep your eye on the gauge especially at higher rpms. If you overshoot the desired PSI by doing this experiment there is no hope of you ever getting your desired low boost out of the turbo u're running just by toying with that arm. On the other hand if you do hit lower than your desired psi, keep loosening the arm and eventually you'll get it although your low rpm psi might suffer.
Basically if you run it once without connecting the rod to the arm, your waste gate will be fully open the entire time, in other words you will have lots of lag and very little boost. Take it to redline and keep your eye on the gauge especially at higher rpms. If you overshoot the desired PSI by doing this experiment there is no hope of you ever getting your desired low boost out of the turbo u're running just by toying with that arm. On the other hand if you do hit lower than your desired psi, keep loosening the arm and eventually you'll get it although your low rpm psi might suffer.
Last edited by triple88a; 08-13-2011 at 08:25 PM.
#38
Junior Member
Thread Starter
iTrader: (1)
Join Date: Jun 2009
Location: Los Angeles, California
Posts: 176
Total Cats: 0
So if I am understanding correctly, increasing the length of the rod will lower the pressure of the wastegate, but at the same time, it will increase lag.
Would it be better to get a more stiff wastegate, lower than 7-8 PSI (what i want) cracking pressure, and use a MBC to raise my boost to 7-8 PSI?
This way, I can have better spool at lower rpms and maintain 7-8 PSI.
I was looking at this wastegate
http://cgi.ebay.com/ebaymotors/T25-T...#ht_1910wt_793
Would it be better to get a more stiff wastegate, lower than 7-8 PSI (what i want) cracking pressure, and use a MBC to raise my boost to 7-8 PSI?
This way, I can have better spool at lower rpms and maintain 7-8 PSI.
I was looking at this wastegate
http://cgi.ebay.com/ebaymotors/T25-T...#ht_1910wt_793
#40
Junior Member
Thread Starter
iTrader: (1)
Join Date: Jun 2009
Location: Los Angeles, California
Posts: 176
Total Cats: 0
I read somewhere about a rule of thumb, such that if I wanted to run at a certain PSI (say 8), I should always get a wastegate that has a cracking pressure half of the desired PSI (4 in this case).
Can anyone confirm that this is true
Can anyone confirm that this is true