Hi Everyone,
I have been looking at turbo upgrades, more specifically the Garrett G25-550 which usually comes with V-Band outlets. A company in Australia offers this turbo with the MHI housing which makes it way easier for me (no need to change manifold or downpipe ect). My question is would the V-Band be better in any way or is the MHI fine in terms of spool and power all around.

Thanks

 

This is going to be highly goal and cost dependent but I really like the OEM look and ease of the MHI setups.
If you plan to swap turbos often, go larger, or something the V-band setup might make sense.

And in terms of spool, the twin scroll MHI setup will out spool a single scroll style setup on the same turbo.

 

MHI all the way if it's available. The twin scroll is a nice thing to have for maximizing response, and the fitment will be far easier with a stock manifold and downpipe. This is a really underrated variable. I've seen the price on those turbos (and it's very high), but you're not paying for a fabricated V-band manifold and downpipe solution, so it's a wash.
I've been waiting for an actual review of a G25-550 or G25-660 on a 4G63, I have yet to see one. It seems life starts at the G30-770 in the US.

 

I recommend G25-550 or go straight to G30-660, skip the G25-660. This vid has the GCG G25-550 with MHI compatible housing installed on an Evo 5. I don't think there's a drop-in G30-660 replacement, so Artec manifold with v-band G30s is the way to go if you want more power than the G25-550. IMO.

 

@spdracerut I think a lot of people dont understand how good twin scroll really is for boost threshold reduction.
I've personally got a G30-660 kit on the shelf because I think the G25-660 is mismatched. Also i'm running pump gasoline only with a 2.3, so I want the extra choke flow to help EMAP.f
I've got 0.61 A/R and 0.83 A/R exhaust housing to play with to get the power band right.
But going from a 5353 (mm) based MHI twin scroll turbo to G30-660 (5556) single scroll turbo will change the spool and transient character a lot.

 

Depends what your doing with the car. If you're autox or doing any time attack or road racing I would stay mhi. Weekend car/ drag car I would go vband so you can get the most out of the. I for one love vband setups simple and clean and easy to work on, also no gaskets to blow out.


He has ran a few g series but in the vband housing

 

Hey, haven't logged in for half a year, so just saw the tag

Curious if you got the G30-660 on? For a street car, I'd agree the twin-scroll helps a lot with the low-end spool-up. But once the engine is in the upper half of the rpm range during higher paced driving, the ball bearing G-series with a good manifold is really good in transient response. I think imperceptible difference with a twin-scroll. But I do think it is highly depending on the manifold design. On my custom S2000 setup, G25-660, 0.72 A/R, GESI 400-cell cat, 3" midpipe, stock rear dual muffler section (so fairly restrictive exhaust setup), shifting from redline in 3rd to 4th, it took about 0.35 seconds from the time I was WOT in 4th gear to hitting my boost target of 10psi.

 

I always recommend turbo kits any more. Getting replacement parts for a garret G-series is much easier than any MHI offering these days. If the turbo fails, 99% certainty you'll be bale to find one in stock and get it shipped to you within a few days vs waiting weeks/months for one of the stock frame turbo builders to rebuild their product. Also, the Gseries turbine housing won't crack and doesn't cost $1000 to replace.

 

I would lean towards the G series. I haven’t driven an evo with one but I just tuned a built sti hatch with a G30-770 vband .83 hotside. Full boost at 4k rpm.

What I was most impressed by is boost recovery, even if taking long lunch breaks in between shifts boost comes back extremely fast, faster than any stock location ball bearing turbo comparable in size although the mhi ball bearing red is about the same.

The turbo is so much lighter than an mhi contraption, artec manifold and a G series has some serious potential not just performance but weight savings as well.