Anti-Surge compressors housings? why? how?

[20vQC]

Hey guys' I've been reading some info about the anti-surge compressor housings and are interesting, dunno what do you say about them. I didn't see any thread reffered to this point so it's good to post it! So, there is some ppl who are machining their turbochargers creating these anti-surge gates\ports around the compressor inlet. On the next pic, you will see a GT22V modified, with those machined gates. On one forum I red this:

"Quote:
Originally Posted by NDgsx
The garret style anti surge ports can change the entire compressor map, not just move the surge line over only.

I actually just saw two compressor maps of the exact same turbo with the difference being a normal housing the the other having an 'anti-surge' housing as you call it. The 'anti-surge' housing not only moved over the surge line, but fattened up the max eff. island of the compressor map; basically making the turbo more efficient over a wider range."


Is that true? So, I can machine my K24-7000 (to give an example) and increase it's efficiency creating those gates? WIll that increase the power or torque of my engine?


OPINIONS ALLOWED

[Jamo]

Yes but not everything is for free, by shifting the surge line you also make the turbo more laggy

Ask S2_Dave he tried one for the 3071

[newsh]

Everything is for free Jamo?

[20vQC]

Yes but everything is for free, by shifting the surge line you also make the turbo more laggy

Ask S2_Dave he tried one for the 3071

That's right jamo, didn't think about it! Fast response! ^^

[Jamo]

Typo! oops

[Billman]

@Jamo

Are you sure that the lag increases? Shifting the surge like doesnt mean that the things that make out the spool characteristics change. Wheels and housing dimentions stay the same. It is only the backwards pulse waves that are coming out from from these holes.

[Jamo]

google it if as usual you dont believe me

[lind4hl]

google it if as usual you dont believe me

Roflmao

[20vQC]

To Jamo. Mate, one question. When it's said that the surge-line moves, it does to the upper (increasing the efficient absolute pressure)? Or does it to the right way (increasing the flow capability)? Cuz if does to the right or both ways, increasing it's flow, then, as you said before, the turbocharger will be more "laggy"! What's your opinion?

[quattro84]

Nope, the map just gets wider on the left side and exposes more of the efficiency islands, and you lose a bit on the right side. Efficiency doesn't get harmed because that involves the compressor wheel.

You can see the ported shroud as an example of a recirculating valve. Some of the pressurised charge after the deflection gets recycled into the compressor inlet.

You don't get any more lag. You are able to build boost faster with a lower displacement of air in stead of passing the surge line (= minimum pump discharge)

I would not modify a standard turbo because you can't be sure how much material is in the casting. If you modify the radius in which the compressorwheel is housed you will destroy it's efficiency.

[Jamo]

That's theory in reality you get lag because the a lot of air recycles through the anti surge ports.

If you don't believe me speak to the UK Garret importers Owen Development , who do kits to delete the anti surge on turbo's such as the 3076r

[Jamo]

For real world S2 results http://www.s2forum.com/forum/showthread.php?p=350136

[quattro84]

For me theory comes in to practice every day. Turbo's are my daytime job MHI turbochargers

The modification that Owen makes is something else, he is only interested in max performance ignoring surge which will wreck the compressor much faster. Especially with a small turbine housing.
In fact you aren't recycling a lot air, it's just the dampened pulsating air deflecting in the opposite direction (current developments reducing it to 2-3%). It only works when the cover is developed to house a ported shroud, useless to modify an old K24.
A wider map is always better. Or your car should have a stationary engine only running at one point in the map.
At some points a ported shroud can even improve spool-up because it makes the turbocharger move in another (read: more efficient) way in the map if matched right to the engine.. in stead of delivering an unstable flow it's delivering a stable flow on a different speedline.

My last 50 cents for this topic. No way i can debate against google wisdom.

[Jamo]

Google or ignore the real life test results? theory is just that, reality bites

[Billman]

My last 50 cents for this topic. No way i can debate against google wisdom.

@Jamo