GT35 ... without the anti surge housing.

Whats the disadvatages of not having the anti surge housing?

What problems will I have without it?

Can I survive without it?

Is it best that i have it?

Does it really matter if I have it or not?

Thanks!

Please help me out... let me know

 

In a nutshell, surging results from the turbo moving more air than the engine can accept, which usually arises at lower rpm. Considering the size of a GT35R in comparison to the EVO's 2.0L, surging should not be an issue, and I see no advantage herein.

 

Most of the Supra with big turbo will selete thier antisurge,why??They said it will add HP,is this ture??

 

I can't see how that would be true looking at the design of an anti surge port.

 

^ Nesiop the design of an anti surge port is made to create a sort of buffer zone around the impeller to stop air that cannot go through the turbo from causing turbulence pre compressor, so if you were to get rid of it I could easily see there being an advantage to having a normal inlet.

Scorke

 

Well considering that all the GT42 GT45 and GT47's only come in the anti-surge housings they obviously work and are needed for good reason, those turbos generally go to very very high boost pressures if you could get a high pressure compressor map of the gt35 that your going to use i could inspect the surge margin, As the name suggests, surge margin provides a measure of how close an operating point is to surge at a given pressure. Honestly if your going to try to run curt brown times with a 35, yes by all means you NEED a antisurge housing, and as above post is correct about turbo pushing more air than the head can injest, this causes an abrupt reversal of the airflow through the unit. Hope that wasnt too technical for you, just wanting to explain things a little better. If your going to keep to "sane" boost levels then you will have little no no adverse affects of not having a anti-surge housing

 

I was saying above I can't see removing the anti surge to add hp like he quoted from Supra owners.

I prefer the surge cover, as the advantage of ANTI surge.

 

Well, that's true. If the turbo is cranked so hard that it manages to kick mass airflow to the left side of the surge line, there will be a problem. One can get an idea of where things will fall via plotting with a compressor map, but for most sane turbo apps, it shouldn't be an issue.

 

Yea I know, the turbine inlet is exactly the same size, just the non surge housing is contoured smooth, And theres too many variables in what a power difference could be if one does exist. On a turbo that size and the boost they are most likely asking of it, could mean any slight variable in tuning/setup can mean a decent size difference in power.

 

Yea, but its really hard to say when he doesnt include any information about his setup/ desired boost levels. I just wanted to throw the information out there,because alot of people have the wrong idea of what compressor surge actually is.

 

Would this scenario be compressor surge?

Go full throttle at 4000 rpms, boost comes up to 28psi (20G9 turbo), let off the gas to about 50%-75%, boost falls down to about 2psi, then you roll back on the gas. As you roll on the throttle you get a very fast da-da-da-da-da "machine gun" noise, the whole car shudders and the BOV opens and closes very rapidly. I can not log in the EMS any abnormalities when this happens - logs look completely normal. This was not able to be tuned out or around with any features of the AEM EMS.

Does that sound like surge?

EVOlutionary

 

I haave that problem on my high boost 100oct map. I've been told to soften up my recirc valve spring, but havent been able to test it yet.

 

The garret style anti surge ports can change the entire compressor map, not just move the surge line over only. This can be good or bad for a given application. I've never seen what the "bullet" or HKS style anti surge does to the compressor map though.
With a 2.0 and a GT14 (35R compressor with a 30R turbine wheel) I had surge problems. I put my 2.4L in and had no problems with a bigger engine.

 

About 3/4 of the way through this vid, there's footage of spool up of apparently a non-surge ported GT-35R on an Evo and you can hear it surge as well as watch the cameraman bounce arond when it happens as well...

http://videos.streetfire.net/search/...65feb4178a.htm

 

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.