Running a T4 without a dump valve?
10-12-2013, 07:27 AM
#1
Running a T4 without a dump valve?
This is apparently not reccomended on bigger turbos, why exactly is this? Excuse my ignorance!
I have heard that bigger turbos W/O DV's are more prone to early failure, does the bigger turbo generate more force when it stalls, is the shaft design on a T4 the same as a smaller turbo? Or simply because the larger turbo is running at higher performance level so the shock load on the bearings is greater when it stalls?
Although I am keen to hear from people who have run a T4 for a long time without a DV and have had no issues, this does not really answer the question in a technical manner. Cheers!
I have heard that bigger turbos W/O DV's are more prone to early failure, does the bigger turbo generate more force when it stalls, is the shaft design on a T4 the same as a smaller turbo? Or simply because the larger turbo is running at higher performance level so the shock load on the bearings is greater when it stalls?
Although I am keen to hear from people who have run a T4 for a long time without a DV and have had no issues, this does not really answer the question in a technical manner. Cheers!
11-12-2013, 03:52 PM
#4
Glennvestite
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Ive heard the boost pressure has nowhere to go so it stalls the turbine and starts to damage it.I dont know if this is true.
Why dont you want a dump valve fitted is it cause you think there chavvy.
Why dont you want a dump valve fitted is it cause you think there chavvy.
11-12-2013, 04:46 PM
#6
Ben
Can't you run a recirc instead?
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11-12-2013, 05:12 PM
#8
big floppy donkey dick
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ive never, ever ran under 30psi, ran a dump valve, or any sort of faggot valve,
always ran Garrett T4 (RS200, RS500 and other types, 4 of them)
Turbonetics T61 at 40ish PSI
never, ever had a failure from broken shaft
always ran Garrett T4 (RS200, RS500 and other types, 4 of them)
Turbonetics T61 at 40ish PSI
never, ever had a failure from broken shaft
11-12-2013, 05:29 PM
#9
Ben
11-12-2013, 06:05 PM
#12
10K+ Poster!!
Never believe what you read on forums and magazines.
12-12-2013, 08:00 AM
#16
Cheers. I've had issues in the past destroying turbos, it always seems to happen when I take the dump valves off. I would assume that the failure is due to stall, but together with a knackered bearing, so you have excess play in the shaft, then bang! So in essence the route casue is not the DV, but the worn bearing, the failure only happens earlier becuse it's stalling?
So at a guess off the top off my head if you had a new turbo with a good bearing, it wouldn't matter about running without a DV?
So at a guess off the top off my head if you had a new turbo with a good bearing, it wouldn't matter about running without a DV?
Last edited by rog; 12-12-2013 at 08:02 AM.
12-12-2013, 09:39 AM
#17
Fast Ford snapper
I love the sound of compressor stall, and I've run three completely different turbo cars without dumpvalves..... but I've had complete failure on each of them!
T34 at 24psi on my Cossie, CR Turbos recently rebuilt that for me and it needed a complete new core. The turbo had only done around 6000 miles since its last rebuild.
T3 on my Alfa Romeo 155 Q4 at under 20psi snapped the shaft at the Nurburgring. I've still got the turbo where you can look inside and see the impeller jammed the wrong way against the housing!
The last 15T on my old Volvo 850 T5 at just over a BAR failed for the new owner not long after I sold it. Don't know the whole story, but I'm guessing it's similar!
I'm now sadly a convert to sneezevalves
T34 at 24psi on my Cossie, CR Turbos recently rebuilt that for me and it needed a complete new core. The turbo had only done around 6000 miles since its last rebuild.
T3 on my Alfa Romeo 155 Q4 at under 20psi snapped the shaft at the Nurburgring. I've still got the turbo where you can look inside and see the impeller jammed the wrong way against the housing!
The last 15T on my old Volvo 850 T5 at just over a BAR failed for the new owner not long after I sold it. Don't know the whole story, but I'm guessing it's similar!
I'm now sadly a convert to sneezevalves
Last edited by Ade; 12-12-2013 at 09:49 AM.
13-12-2013, 08:30 AM
#22
13-12-2013, 01:12 PM
#24
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I fucking HATE the sound of dump valves, and LOVE chatter, but let's cut the BS and have some facts here.
I've personally seen, in the flesh, as it happened, at least 2 (possibly more, can't remember) RS500 T4s snap shafts, and both were with no dump valves. Countless others in the same situations with no turbos dying.
MOST other turbos cope way better without one, I've ran many cars at 1.5-2bar with no DV and no issue. I think quite possibly the RS500 T4 is a very big compressor for a very thin shaft, so it doesn't cope as well.
You might not realise, but while the air stalls without a dump valve, the shaft speeds up. This is why the thing about DVs helping response is total BS, but they can indeed help turbos live (honest, sounds wrong, but tis true).
Also, DVs with very strong springs that chatter THEN dump are fairly useless, as tbh the damage is already done then.
I've personally seen, in the flesh, as it happened, at least 2 (possibly more, can't remember) RS500 T4s snap shafts, and both were with no dump valves. Countless others in the same situations with no turbos dying.
MOST other turbos cope way better without one, I've ran many cars at 1.5-2bar with no DV and no issue. I think quite possibly the RS500 T4 is a very big compressor for a very thin shaft, so it doesn't cope as well.
You might not realise, but while the air stalls without a dump valve, the shaft speeds up. This is why the thing about DVs helping response is total BS, but they can indeed help turbos live (honest, sounds wrong, but tis true).
Also, DVs with very strong springs that chatter THEN dump are fairly useless, as tbh the damage is already done then.
Last edited by WTF?!; 13-12-2013 at 01:13 PM.
13-12-2013, 02:49 PM
#26
Ben
15-12-2013, 09:15 AM
#28
Happily retired
My Tuner Spec's my engine so if I open the bonnet & see a DV its because its required. Too many non-experts on here giving advice as is always the case.
My advice
is never listen to advice on an internet Forum.
When I used a T4 about 700 years ago it had a DV fitted so it was required we ran 42psi back then. Another bit of advice you must not listen to is fit a DV & ditch the T4 it was outdated in about 1990.
My advice
is never listen to advice on an internet Forum.When I used a T4 about 700 years ago it had a DV fitted so it was required we ran 42psi back then. Another bit of advice you must not listen to is fit a DV & ditch the T4 it was outdated in about 1990.
16-12-2013, 08:10 AM
#29
Looks like it's staying on.
I do agree about the internet forum advice in most cases, but it's also nice to research these things for yourself from time to time and get input from more than one person. I searched for info on this topic already and couldn't find anything so hopefully this will help someone else if they are considering it.
I do agree about the internet forum advice in most cases, but it's also nice to research these things for yourself from time to time and get input from more than one person. I searched for info on this topic already and couldn't find anything so hopefully this will help someone else if they are considering it.
16-12-2013, 12:29 PM
#30
My Tuner Spec's my engine so if I open the bonnet & see a DV its because its required. Too many non-experts on here giving advice as is always the case.
My advice is never listen to advice on an internet Forum.
When I used a T4 about 700 years ago it had a DV fitted so it was required we ran 42psi back then. Another bit of advice you must not listen to is fit a DV & ditch the T4 it was outdated in about 1990.
My advice
is never listen to advice on an internet Forum.When I used a T4 about 700 years ago it had a DV fitted so it was required we ran 42psi back then. Another bit of advice you must not listen to is fit a DV & ditch the T4 it was outdated in about 1990.
Horses for courses rod
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