I'm in the process of upgrading an evo 9 turbo I recently bought that needs rebuilt into an hta 73 green. I have the option of upgrading from the 64mm housing to the 84mm fp anti surge housing. It will cost an extra $150. Is the upgrade worth it? I am currently on sd with a 4 inch intake anyway. Any input would be great. Thanks

 

Yes it will definitely be worth it

 

yes get it, sounds cool and it is good for the turbo and looks cool at the same time!

 

Yes.

 

It depends. Numerous people have reported that the surge cover hurts spool. It was developed to alleviate, yes you guessed it, compressor surge. Most people that complain about surge have a stroker motor.

Yes the covers look cool and they make a sweet noise. But it was designed to alleviate surge at the expense of a little spool.

For me, the thing I want most is a fat powerband. The wider the tq curve the better. As such the quicker it spools the better.

 

thanks for the great input guys. I'll probably go ahead and get it. I don't track the car or anything. Just enjoy driving it on my day off. Everyone says it sounds sick and in theory will help extend the life of the turbo. One other question I have is am I able to use the stock ix wga with the hta73? I don't see an option to purchase the 18 or 25psi wga from fp.

 

I was looking for their WGA's on their website the other day and didn't see them either. You could always do the stock spring mod

 

I'll look into that. Thanks man

 

Here's the how-to thread on it.

https://www.evolutionm.net/forums/showthread.php?t=305565

 

the boards are just figuring out how much a shrouded cover hurts spool and low speed drivability. switched from ported green to unported red and the red is more responsive and more fun to drive. ported covers are likely killing about 20hp through the midrange as well . they are very turbulent. the air noise we treasure as cool is essentially a boost leak

 

Stock ECU steps the boost map every 500 rpm. I was experiencing surge at 3200 rpm and had to reduce boost from 3000-3500rpm and then ramp it back up a bit to get the boost back where it would have been.

Using a surge cover, reducing boost to avoid surge may not be required.

So, did I lose torque due to having the cover as opposed to reducing boost to avoid surge?

I'm not sure.

Also, I like being able to give quick throttle inputs in 5th/6th gear while cruising and not having to worry about the turbo surging.

 

Unbelievable but from your other threads I know you are knowledgeable person.thanks for letting us know.

 

surge can be tuned out through the ecu. especially with mivec. but even when you dont or cant you can generally drive around the surge zones. for instance if you have surge at 3200 rpm in 4th you learn to 75% throttle in that area. not sure if its costing hp or not between tuning out surge with non ported cover and not having surge with ported cover. both methods are achieving same end. but you have no leak control with a ported cover. if it leaks more in a zone that doesnt need to be leaking you are loosing hp in that area. "that area" is actually huge. from 2000-3500 rpm there is no real surge threat. in that rpm region the ported cover feels like a 2.0. with a non ported cover the engine feels like a 2.3. its a big difference.

 

I think there might very well be a lot of ways to deal with surge that don't deal with permanent leaks .. bov tuning and waste gate tuning are huge and so often overlooked .

 

https://www.evolutionm.net/forums/ev...ort-cover.html