Compressor surge, Is it really that harmful ???

[BlitzBoy]

Luv to see to see these pics of these big single turbos with broken blades due to surge, the only ones i have seen broken is due to debris getting into the compressor housing.
Anyway im not really arguing there is evidence for and against BOvs. I run without because of performance and have had no ill effects in two years of hard driving on my turbo, plus speaking to guys down under who are into drag with similar sort of setups to me also run without bovs coz of performance

[Timmy]

No because a wrc has this little thing called anti lag and it\'s alot more than just a throttle kicker. So the turbo produces boost without any throttle caused by an injector in the exhaust manifold.
I think you\'ll find if you look at the boost gauge with or without a dv the system looses all boost pressure.
In fact i don\'t think there are any performance gains from not running a dv at all.
As carl said full throttle changes when you do a drag run so maybe there\'s room for improvement on you 11.39

[Carl]

Come on Mark,tell us about your new bridgeport.
Regards
Carl

[bobert]

Ok, what other reason is there for blades to come off a Garrett turbo?? i was only told it was Due to Surge.

We aint talking top end best you can buy turbo\'s, lets face it most of the T series are x truck?

exactly.

who knows the history of the turbo plus a lot of turbos on the market are old truck technology, not designed for loads of boost pressure.

[Timmy]

If a turbo is run with a filter so no debris can get in the fins can only be caused by 2 other things imo. Bearing failure cause shaft play so the fins touch the housing. Obviously on stip down you\'d have lots of shaft play or compressor surge.

[Carl]

Mark,
here is a couple of pics of the second fastest rotary in the world up the strip,you are right,they are not running a dump valve,they are actually running two!
Regards
Carl

[Timmy]

has that thing got 3 turbos?

[Carl]

has that thing got 3 turbos?

Yes it has.
Regards
Carl

[Carl]

Even Abel Ibarra has on his car which is the fastest rotary in the world.
Look at this vid where you can clearly see it/them.http://videos.streetfire.net/video/f1e022e3-bcb6-4843-91a0-99b001670330.htm
Regards
Carl

[BlitzBoy]

lol for every picture you post of a drag car with a BOV I can post several pics of drag cars without BOVs Carl, plus I have intercooler and more length of tubes to pressurise rather then the methonal cars without coolers, I am more concerned with the class of car that im up against, and with my setup my car is quicker without a BOV in this case

[BlitzBoy]

turbine is constantly spinning whilst the engine is running whether at WOT, cruise, foot off the gas etc

bare in mind that the expansion of the thermal heat has more effect on the turbine spinning then flow of the gasses, hence why some people use turbo beanies to keep the heat in the rear turbine of the housing.

As I said there are Pros and cons to Dump valves. On my setup with an intercooler and long pipes is beneficial not to have a dump valve,
There are Drag cars they dont run them and some that do, remember these guys test all the time and would either add or take them off if it makes their cars quicker, some find they are quicker without them.
Anyways we can debate this till the cows come home, im going to bed lol

[rotari]

Mark,
here is a couple of pics of the second fastest rotary in the world up the strip,you are right,they are not running a dump valve,they are actually running two!
Regards
Carl

I\'m also loving the lack of Intercooler! But then they make up for it with the massive front mount oil cooler! Suppose not worth the extra weight -not exactly like it be doin big distances.
 
What size you recon the three turbo\'s are? Bet that was an interesting choice as to what to go for.

[SiH]

As an aside - there are some production FI cars that are not fitted with recirc/BOV valves :nod: S13 200sx for one...

[Carl]

I\'m also loving the lack of Intercooler! But then they make up for it with the massive front mount oil cooler! Suppose not worth the extra weight -not exactly like it be doin big distances.
 
What size you recon the three turbo\'s are? Bet that was an interesting choice as to what to go for.

I don\'t know what turbo\'s they are,maybe something like  gt35r\'s,but the reason for no intercooler is they are running methanol for fuel which in itself has a very dramatic cooling effect.
Regards
Carl

[marco]

If you run a recirculating dump valve then you don\'t lose any boost at all.
Regards
Carl

by this do you mean recric it into the intake as on the stock set up? surely the only way you could maintain boost would be if the air filter provided sufficent restriction to ensure the pressuried air went to the turbo inlet rather than to atmosphere through the filter. if this was true then the turbo would have to overcome a large presure difference to get ari into the engine during normal operation- hindering performance. this isn\'t the case as air filters are designed to provide as little restriction as possible, and so the pressure is going to dissipate very quickly.

on the other hand whilst the preasure from the dump/recirc valve will reduce to atmospheric rapidly, the temperature diffusion of the hot air put into the inlet would be much slower- so when the turbo did spool up again after gear change or whatever, it would be drawing in hot air pretty much straight from the turbo outlet. so from a preformance point of view, it would be slightly better to have the dump valve going to atmosphere, as in effect that is all a recirc valve does anyway, and it eliminates a source of hot air into the intake?

Obviously i could be wrong on this and await my argument to be shot to pieces.....

marco