I understand that as well. Once again hes referring to a person that already has a applicable non gated turbo on there truck. Hes referring to "retrofitting" a external gate as an "up grade" on a already installed and functioning, non-gated turbo......
A brief overview of a turbo system 'components' in the context of an IDI
- Thread starter Heide264
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Heide264
Full Access Member
I think we are starting to 'nit pick' a good bit here.
The general idea is that a wastegate isn't your first decision when choosing a turbo. You pick your ideal turbo flow characteristics... and then you decide whether you need a waste gate or not. If you want to be in an efficient area of your map that is moving a good amount of air early in your RPM band, you will probably need a waste gate. If they sell one that fits your specs and bill and has a wastegate built in, great. If not, you can always add an external.
It's not that a waste gated turbo always has better spool characteristics... its that you chose a small turbo and it required a wastegate. Not a bad thing, it just is what it is. Garrett makes turbos... they don't decide applications (For the most part).
For the record, I had to externally gate my STi on the stock turbo. It's annoying, but it happens. The stock turbo is intended for a lot of torque earlier in the RPM band, and it doesn't do well at the higher CFMs required towards redline. The internal wastegate on the factory turbo is actually too small to allow enough air around the turbine. I am aware that this is a 'gasser', but its still some food for thought.
brokeasajoke
Registered User
I always thought boost controllers were inline on pressure hose to WG to adjust pressure to the wastegate just like an airpressure adjuster on a aircompressor allowing higher pressures before WG opens to bypass exh turbine.
Heide264
Full Access Member
That sounds like a standard 'boost controller' to me. I think of a boost controller as a device that selectively 'blocks' the wastegate actuator from seeing the actual manifold pressure. They'll allow a wastegate actuator to use a small spring (5psi) and run significantly higher boost pressures. The WG actuator on my STi opens at about 7psi. Using an electronic solenoid, I run up to around 23psi at peak torque.
The company's design the waste-gate-actuator with a set tension spring to control the boost, springs can be changed to change the set tensions in turn changing the boost level. A MBC can be used to do the same at least on gas applications, my exhaust break waste gate requires no vacuum line. my banks is non-gated
brokeasajoke
Registered User
STI nice. I remember playing with the subaru turbo wagons from the 80s and talons and eclipses were the ticket in the 90s. Im gettin old.
so once again your question is:
"Why cant you external waste-gate a non-waste gated turbo?"
-----------i never said that you could not.
What will that doo?????
Heide264
"Perhaps you already have a non-wastegated turbo and it would be cheaper to retrofit an external one."
how will this work????? what will the waste-gate then do?
so a guy has a non wastegated turbo on his truck and hes running it. it does 10 psi. You asked why you cant just put a gate on that.........
Why would you put an external gate on it and would would be the purpose of the gate?
broke: i have a '95 tsi and your absolutely correct
Heide264
Full Access Member
Not all waste gate actuators can have their springs easily swapped out. Many are sealed shut from the factory and you are either stuck adjusting the pre-load (if the actuator arm has an adjustable length) or getting lucky hitting the sucker with a hammer to 'smash' it a bit.
There is no difference between a diesel and gas application with boost controllers. They either modulate a pressure 'signal', block a pressure 'signal', or allow a pressure signal through to the wastegate actuator.
Heide264
Full Access Member
Ha, yeah. They are fun. I wish they were a bit cheaper to play with, but oh well. The newer ECUs in them drive me up a freaking wall. I don't need a several 32x32 fueling tables... its a headache at times.
I wouldn't, obviously.
Say a guy drops a non-wastegated turbo on his truck that he found at a junkyard and starts running it. it does 10psi at 1.5k RPM, but does 25psi at redline. You want 20psi at redline. Guess what you could do?
If it is so big it does 25 psi it will not do 10psi at 1.5k nice try though
the bigger it is the worse the spool time thats just turbo 101
As ive tried to tell you non gated diesel turbos have larger exhaust housings for its intended application and thats going to add to the fact that it wont spool.
the bigger it is the worse the spool time thats just turbo 101
As ive tried to tell you non gated diesel turbos have larger exhaust housings for its intended application and thats going to add to the fact that it wont spool.
Heide264
Full Access Member
Man, I dunno what you want. It was a figurative example.
I think anybody here is capable of understanding a turbo could be ideal lower in a rev band, and be out of it's efficiency range at a higher RPM... regardless whether it has a wastegate or not. I don't really understand the issue here.
This above quote is sarcasm and was originally in this post. Please don't take it seriously or for fact. I'd delete it, but it's quoted elsewhere, I believe. Sorry.
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well this began with you telling me waste-gated applications dont have smaller exhaust housings............ that waste-gates have nothing to do with exhaust housings size.....
.....then you proceeded to tell me i dont know what im talking about........
now your saying they have smaller exhaust housings on them and im not an idiot that has no clue what hes talking about???
an 18 wheeler will have a giant turbo on it compared to what is applicable on a 6.9 7.3 ih idi
why would a 18 wheeler with a giant motor have a tiny turbo on it? you have absolutely no clue what your talking about...again
