I don't know Zack nor am I familiar with any g25 results. You posted a link to the 2.2L non MIVEC setup running this G30-770 turbo and then you posted the Excel file showing the spool so all of that was the basis for my comments. I've probably had 10 different turbo setups on the EVO and a few that were dog lazy, even worse than the G30 results. I personally don't recommend anyone use the G30 with an open scroll nor do I recommend anyone use the G30 on a stroker motor because a 55mm turbine exducer is too small.

 

is g30-770 lazier than gtx3076 gen 2 or am i mistaken?

 

Who is this Zach person I keep reading about?

 

So this should be best considered a pre-order advertisement? https://www.atpturbo.com/mm5/merchan...Series-G30-770

 

That is probably an ATP manufactured turbine housing similar to their original 1.06 a/r turbine housing I used with the GTX3582r. I had the original cast iron version of that housing, but was told the later stainless version of that housing was cut with excess tolerances for the wheel. So much so that a GTX3584r turbine wheel would fit despite being slightly larger.

 

LOL ok bud

 

It definitely should not be. G30-770 is basically the new GTX3071. So 71mm exducer compressor wheel compared to the 76mm on the GTX3076.

 

I believe the g30-660 is the new 3071 gtx 2 based on the horsepower rating. I guess i have to pull the trigger and order a g30-770 to see for myself.

 

By flow, yes. But by physical compressor wheel exducer size, the G30-660 has a 67mm exducer compressoer wheel like the old GTX3067. So the G30-660 should make power like a GTX3071, but have better transient response because of the lower mass and inertia of the smaller 67mm compressor wheel compared to the 71mm in the GTX3071.

 

Well it looks like I'm waiting until September (possibly). This is why I can't have nice things...

 

I have a g30 1.06 T4 divided housing in my hands. It's a Garrett part bought through my tuner, who's a distributor. My understanding is that the g35 divided t4 housing is available now too. They're both on the atp site with part numbers.

I'm not a regular user here, but I thought I'd share because this thread was where I got a lot of my info while I shopped turbos.

For me, it's a g30-900 going on a stock bottom 2jz-gte vvti, can share results in 4 to 6 weeks if anybody's interested .

 

For a 2J with VVTI, I'd go G35-900 for sure. With that much displacement and VVTI, the G35 turbine is a better fit. Not to mention, G35-900 is a better matching of compressor and turbine resulting in better turbine efficiency than the G30-900.

 

Too late. But really, this is a street car(near daily) that has been making 600whp for years and can't put the power down most of the time. A g35-900 is definitely a better fit for most 2jz cars, and could make more power, but I'm trying not to make more, just spool earlier. I was eyeing a g30-770 but my tuner felt more comfortable with the 900.

As far as the match goes between compressor and turbine, I'm really curious to see how this works. If you look at the turbine flow map, the g30 is super close to the old gt(x)35. Seeing it in person, the turbine looks tiny. Gonna trust Garrett on this one for now.

 

ATP confirmed it is indeed an official Garrett released housing.

 

When I say compressor to turbine match, I'm referring to the resulting blade speed ratio. I apologize, I should have been more clear. Put the G35-900 in that same T4 1.06 twin scroll housing casting, and it'll spool as quickly as the G30-900 but probably free up about 50whp maxed out. It's very analogous to the GTX3076 vs GTX3576 comparison as they are the same mix of compressor/turbine wheel diameters, the same 76mm diameter exducer compressors put on GTX30/G30(60mm) and G35/GTX35(68mm). Putting the G35 turbine in the same housing as the G30 with both paired to the 76mm exducer compressor, the G35 will flow more resulting in less back pressure. But the G35-900 has better turbine efficiency because of better blade speed ratio due to better match of compressor and turbine diameters. So it can spool up the turbo as quickly, i.e. the same turbine power. Turbine power is a function of efficiency and pressure ratio. More of either and you get more turbine power. With the larger G35 turbine, you will have less pressure ratio to drive the turbine, but better turbine efficiency resulting in the same turbine power to spin up the compressor wheel. I would say the 1.06 A/R for a G30 size turbine is also a bit outside of ideal for turbine efficiency. Larger diameter turbines tend to have their peak efficiencies in larger A/R housings, and vice versa. 1.06 A/R size is better suited to the larger G35/GTX35 turbine diameter. If you look at the smaller OEM gas turbos (~GT15-GT17 size), like on the Ford V6 Ecoboost, they are 0.49 A/R. Look at the big GTX50 stuff, and they are around 1.2 A/R, approximately. If you're a cyclist, a mismatch of compressor to turbine wheel sizing is kinda like being caught in the wear gear pairing. The G30-900 will still be a lot of fun, just leaving some power on the table. Jackie Ding in his AMS Supra time attack car is doing pretty well with the G30-900.

In going with the G30-770, you'd probably gain about 300rpm of spool compared to the G30-900, but have about 50whp less maxed out. About 100whp less than the G35-900. But the G30-770 would be very snappy and responsive, having the lowest rotational inertia and good turbine efficiency.

https://motoiq.com/turbo-tech-compre...map-details/3/