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Skyline R33 25Gts-T Help Blow Off Valve

IronPat
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tripsteady Proficient

tripsteady

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Posted

Lol , harsh but understandable responses...i too preferred this sound but once I learnt about the physics of the whole thing , I decided my turbo was more important then a sound. Anyone reasonable will come to the same conclusion. The sound is from the fact that the bov is blocked off/not working correctly , leading to air rushing back towards the turbo when the throttle is closed shut. This hair is chopped up by the blades of the turbo leading to the psh psh psh. If you hear this sound it either means that your bov port is blocked or it isn't working correctly. The pressure on the blades usually doesn't do much but in a series 2 r33 the wheel is ceramic not steel and is more susceptible to being damaged. If you really want the sound , as stated above , all you have to do is block of the bov but this may (and is still highly debated) shorten the life of your turbo , especially if its ceramic wheeled.

tripsteady Proficient

tripsteady

Posted
Posted

I was under the impression that it's only the exhaust side that's ceramic on a R33 turbo?

yes this is correct however there have been many failures , thought to have been caused by a blocked bov on series 2 ceramic wheeled skylines as opposed to much less failures to on the s1's . Like I said its still a hotly debated topic as to whether it does any significant damage (you'l hear the vl guys talk bout their hectic flutter setup running strong for 3 years on the stock turbo)...but Id rather keep away from that , fit a pod and just be content with the "whoosh" sound.

Tai1or Made Grand Master

Tai1or Made

Posted
Posted

Yeah trying not to start that debate.

But.

How does the air on the intake affect/effect the ceramic blades on the exhaust side?

The pressure on the blades usually doesn't do much but in a series 2 r33 the wheel is ceramic not steel and is more susceptible to being damaged.

tripsteady Proficient

tripsteady

Posted
Posted

Yeah trying not to start that debate.

But.

How does the air on the intake affect/effect the ceramic blades on the exhaust side?

it shouldnt...at all...as far as i understand..just pointing out that for some reason the ceramic wheeled turbos arent that tolerable as the completely steel wheeled ones... Id lean towards the compressor wheel being made of nylon in the s2 having something to do with it as well.

if im spewing wrong info , il be more then happy to be corrected as I am fairly new to skylines myself.

Hanaldo Grand Master

Hanaldo

Posted
Posted

Nylon is very very strong. Frankly, I have my doubts that air flowing back through the compressor will do any damage, as there is no load on anything. Actual compressor surge which occurs on throttle when the engine can't consume the air being generated by the turbo; that I could understand how it would damage things as there is significant load on the turbine and therefore the compressor.

But when the shaft is just free-wheeling in decel and off-throttle situations, there is very little resistance to the air flowing backwards. Perhaps on already weakened blades it might put enough stress on them to be the final straw on the camels back to cause major damage, but otherwise the wheels should be built to handle much more stress. The only harm I can see it doing is to performance.

And performance is good. Don't do flutter kids.

joeyjoejoejuniorshabadoo Grand Master

joeyjoejoejuniorshabadoo

Posted
Posted

yes this is correct however there have been many failures , thought to have been caused by a blocked bov on series 2 ceramic wheeled skylines as opposed to much less failures to on the s1's . Like I said its still a hotly debated topic as to whether it does any significant damage (you'l hear the vl guys talk bout their hectic flutter setup running strong for 3 years on the stock turbo)...but Id rather keep away from that , fit a pod and just be content with the "whoosh" sound.

i for one would like to see these failures.... i have been around sau for quite a while now and i don't recall ever seeing 1 confirmed failure caused by a blocked bov.

also let's not forget R31 and Cefiro RB20 motors never had a bov from factory...

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