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Wastegate necessary?
by
Rabbit TD
on 26 May, 2009 17:51
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At what point is it necessary to bleed off excess boost on a everyday car. A T3 is supposed to open around 10 from what I've heard but the other people run 15-18 so is it necessary to have a wastegate on a small t3 that probably won't go much more than 10 0r 11 anyway set not to open. I have an old t3 with a bad actuator and want to try it. I lapped the valve tonight and would like to try it and compare it to my rebuilt one which I think is too big for my use.
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#1
by
RabbitJockey
on 26 May, 2009 18:25
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you don't need one alot of industrial and truck diesels do not have them. my k24 was jammed shut(they're notorious for this) you will only be able to get as much boost as the fuel you put in. the stock t3 or k24 under stock fueling will only see around 15psi with a closed wastegate. make sure you plug or remove the bov. but i think a smaller turbo will probably make more boost with less fuel.
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#2
by
Rabbit TD
on 26 May, 2009 18:52
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you don't need one alot of industrial and truck diesels do not have them. my k24 was jammed shut(they're notorious for this) you will only be able to get as much boost as the fuel you put in. the stock t3 or k24 under stock fueling will only see around 15psi with a closed wastegate. make sure you plug or remove the bov. but i think a smaller turbo will probably make more boost with less fuel.
Thanks for your answer, I got a rebuilt turbo from mjm turbos this past winter and I don't think it's doing what it should and I want to try the old one without a wastegate cause the canister and diaphram are shot but otherwise it seems ok but I never ran it. Right now I just have the N/A pump on it because I'm still working on the T/D one but even in the beggining this new turbo didn't put much out even with it. The T/D pump leaks and I haven't put it back on yet since I got it straightened out. I still don't know a lot about turbos but if I knew then what I know now I wouldn't have got this one with the stage 1 conversion, I just have a feeling it's too big of a compressor for this engine for my use even being just a stage 1. It could possibly have a leaking valve as it's one of those that are damn near impossible to get apart without ruining the actuator and I doubt the valve was lapped when it was rebuilt.
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#3
by
RabbitJockey
on 26 May, 2009 19:43
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once you have the td pump you may see why a bigger compressor is a better compressor.
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#4
by
Rabbit on Roids
on 27 May, 2009 10:24
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yea, i would keep the big turbo on there, and try to throw enough fuel at it to get it happy. thats why i went with twins.. i had a spare useable T3 laying around, and my turbo was just too small for all the fuel i was giving it, wouldnt make near the boost i wanted it to. so i strapped a T3 on there too. i dont really have much testing or time on my new setup since i cant drive the car (legally). or you could put a little turbo on there, then bolt your big T3 on after the little guy. that would probably spool nicely.
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#5
by
Smokey Eddy
on 27 May, 2009 17:13
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#6
by
Rabbit TD
on 27 May, 2009 18:08
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once you have the td pump you may see why a bigger compressor is a better compressor.
That's one of the problems, I did have the T/D pump on when I first put the engine in the car and the turbo didn't do much with it either and then I had to go back to the N/A pump because of leaks in the T/D one. I have it re-bushed and resealed but not back on yet and want to try this other turbo just to see if there is any difference one way or another. I just have a feeling this turbo leaks either at the valve or where he machined the case for the bigger wheel {too much clearance}?
One thing I do remember though when I had the T/D pump on at first just accelerating through the gears moderately the EGT's would really climb just on flat ground with little to no smoke and still no more than 5 lbs. boost. It was in the middle of the Winter at the time and I thought there is no way I can drive to work like this with the mountains I cross in the Summer when it's in the 90's.
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#7
by
Rabbit TD
on 27 May, 2009 18:26
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#8
by
Rabbit TD
on 30 May, 2009 19:40
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you don't need one alot of industrial and truck diesels do not have them. my k24 was jammed shut(they're notorious for this) you will only be able to get as much boost as the fuel you put in. the stock t3 or k24 under stock fueling will only see around 15psi with a closed wastegate. make sure you plug or remove the bov. but i think a smaller turbo will probably make more boost with less fuel.
Thanks for your answer, I got a rebuilt turbo from mjm turbos this past winter and I don't think it's doing what it should and I want to try the old one without a wastegate cause the canister and diaphram are shot but otherwise it seems ok but I never ran it. Right now I just have the N/A pump on it because I'm still working on the T/D one but even in the beggining this new turbo didn't put much out even with it. The T/D pump leaks and I haven't put it back on yet since I got it straightened out. I still don't know a lot about turbos but if I knew then what I know now I wouldn't have got this one with the stage 1 conversion, I just have a feeling it's too big of a compressor for this engine for my use even being just a stage 1. It could possibly have a leaking valve as it's one of those that are damn near impossible to get apart without ruining the actuator and I doubt the valve was lapped when it was rebuilt.
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Well today was a good day finaly. I have been wanting to try the old turbo {stock t3} that was on the engine when I got it. I haven't rebuilt it yet but I did tear it down enough to lapp the valve and put it back together without a wastegate just to compare it to the turbo I got that doesn't make much boost for my needs. Boy what a difference it made, just letting the clutch out is even better and the engine is way more torquey in all ranges. I was in 4th gear one time and I thought I was still in 3rd the way it was pulling just putting around on these back roads. Just like they say the smaller ones start making boost quicker and I also have way more boost than before with the stage 1 abortion I bought. I let it wind up in 4th on this one stretch of road I use and it climbed to 10 psi where the other one would only show 5 and I still have factory fuel settings and am currently using the N/A pump and still no smoke, I think I'm getting on the right track now finaly and the old rabbit is hopping along a lot better now. I was starting to get pretty frustrated with this thing with all that I did to it. I still have to put the T/D pump back on yet though. I re-bushed and re -sealed it but when I tried it a while back I couldn't get it to start. Since then I took it back apart and checked it out and all seems well, I just haven't tried it again yet but it should make a big difference. But just today with this old 432,000 mi. t3 it feels like I picked up at least 10 or more horses and the turbo doesn't seem to be leaking oil either, it might not be the original though but it doesn't have any more shaft play than the rebuilt one with just 4,000 on it now.
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#9
by
MJF
on 01 Jun, 2009 06:59
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DonŽt block the wastegate. YouŽll need to control boost, boost does not make power. Industrial and truck engines have so big turbine housings that boost will not get too high, these are not made for horsepower/quick spooling.
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#10
by
53 willys
on 01 Jun, 2009 07:55
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DonŽt block the wastegate. YouŽll need to control boost, boost does not make power. Industrial and truck engines have so big turbine housings that boost will not get too high, these are not made for horsepower/quick spooling.
X2 this guy knows whats hes talking about!! wastegate is your friend....unless you like rebuilding turbos.....
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#11
by
arb
on 01 Jun, 2009 10:11
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DonŽt block the wastegate. YouŽll need to control boost, boost does not make power. Industrial and truck engines have so big turbine housings that boost will not get too high, these are not made for horsepower/quick spooling.
X2 this guy knows whats hes talking about!! wastegate is your friend....unless you like rebuilding turbos.....
Think about it this way, The wastegate is the speed govenor for the turbine wheel. Without it, you could easily over speed it and damage it.
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#12
by
zukgod1
on 01 Jun, 2009 10:27
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No waste gate = BAD!!
I have pieces of turbo's on my bench at home. Overspeed and BOOM!!!
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#13
by
Rabbit TD
on 01 Jun, 2009 14:13
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DonŽt block the wastegate. YouŽll need to control boost, boost does not make power. Industrial and truck engines have so big turbine housings that boost will not get too high, these are not made for horsepower/quick spooling.
X2 this guy knows whats hes talking about!! wastegate is your friend....unless you like rebuilding turbos.....
[/qute]
I'm not planning on turning the fuel screw way up and all that just to see how much I can get, I want this thing to stay economical too and after just todays drive to work for the first time with this turbo it is definately running more economical and way more power especily on the mountain. I saw it hit 8 for a little bit and the EGT was around 1100 and the water temp never got over 190 about 80 degrees outside. My question about the wastegate is that they aren't supposed to open on these little t3's till around 10 anyway aren't they? So if i don't ever see more than 10 anyway what harm does it do if it is blocked and secondly how do these people run with these high levels like 20 and above and get by with it. I know I'm never going to see anything like that for my use. I do understand the overspeed issue but is it a problem at the 8-10 psi level and all the temps way on the safe side and almost no smoke at all even pulling a mountain?
