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G35 1050 vs G42 1200 on a 13B - Best Choice for 600hp?
Good Afternoon Gentlemen,
Does anyone have any data on the G35 1050 and G42 1200 turbos or preferably something similar on a 13b large street port with all the supporting mods for 600hp?
I'm not entirely sure if the G35 1050 will make 600hp on a 13b? I've not got the expertise to make sense of compressor maps etc so hoping someone more skilled can provide some helpful info on what they think each turbo could approximately run on a 13b large extended street port at approx 15 psi, 20 psi and 25 psi of boost please on pump fuel and water/meth?
However, the above link is for a piston engine on 31psi of boost...so only posting this as a reference....not drawing any conclusions from that but as I understand it a 13b rotary will need 30% more air to make the same power as a piston engine?
which if you compare the compressor maps the G35 is going to be much more efficient in the top end range; 70% efficiency at 30 psig starts around 53 lb/min on the right all the way across to 70% at 95 lb/min
The -900 is going to come up maybe a hair short maxing out 78 lb/min @ 30 psig, but it’s doing 72% efficiency there. Which might allow using the smaller G30 for great spool and tolerable emap up top. Definitely going to need the speed sensor to avoid exceeding the rpm limit with it still being so efficient there. The overall efficiency range is more compact at that higher boost level on the 900 compressor, starting 70% with 34 lb/min @ 30 psig straight across to hitting that max flow/rpm limit at 72%.
You’re going to need ~80 lb/min to hit 600 whp. I’m not sure you can get there with that level of porting at a lower boost level. Someone else more familiar with that here will need to offer guidance on it.
there’s a barely used G35-1050 1.06 T4 for sale on fleabay, guy seemed to have an attitude when I inquired about it (dropped the price some afterward), but am really looking at the -900 for low-mid 500 whp on an RX8-REW conversion
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For 500 whp you’re better off looking at the G30-900 1.06 A/R divided T4 for spool response imo. The G35-900 is likely going to be a bit slower to spool up, but then likely better emap at peak power.
The compressor maps are straightforward for comparing and assessing the flow/power potential and efficiency differences.
The GT35 is well known here. Yet it seems as though it’s still not recognized how much of an improvement the G-series is over it. Garrett hasn’t released the exhaust flow map for the new 1.06 A/R divided T4 housing yet. However the G30 turbine map reveals that it’s 1.01 AR turbine flow curve is a very close match to the same A/R GT35 turbine flow curve.
The thing is, the G30 is doing it with a much smaller turbine wheel size. The compressor wheel is also much smaller with more potential. Because the efficiencies for both wheels is up substantially. The benefits of smaller wheels wrt to MOI/response are obvious, but nobody was looking too hard at them because of the initial V-band only turbine housing options.
The G35 1.06 A/R is going to outflow the same A/R GT35 turbine housing enough to assume that along with the larger turbine wheel it will likely respond/spool slower that the G30. These are only general assumptions though that seem reasonable to me based on the information available.
The only thing we really have at the moment for actual rotary result comparisons are Rob Dahm blowing right on past 1000 whp with the G42-1450 1.28 divided T4 on a 20B recently and also Brettus over on RX8Club making 430 whp around 1 bar on a Renesis using the G30-660 1.01 V-band.
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Thank you, I had not considered the G30-900 at all. It's fascinating that the G30-660 made 430whp at 1bar of boost.
May need to take a closer look at the G30-900 and G35-900 if i choose the 500whp option.
I was looking at the bigger G35-1050 and G42-1200 compact to see if they would be able to flow 600+whp easier without running too high boost pressures. Ideally not much higher than 25 psi as i intend to run pump fuel and water meth only.
Well that will come down to how much lag you can live with, but more importantly I think porting is going to play a lot into it as well. Because I’m not sure you can achieve that power/boost level without opening up the ports more, whether bridge, semi-P, or full-P. That’s the general trend I see, but is out of my comfort/experience level though.
So somebody else will need to guide you on that. In fact, with full disclosure at least one person on RX8Club would tell you I’m an idiot who understands nothing about nothing, but the numbers presented stand on their own accord.
The G35-1050 can get to 80 lb/min no problem and with good efficiency range. The G42-1200 is going to be quite a bit behind it on response, but likely with slightly lower discharge temp and emap. 600 whp would be dead center of peak efficiency island on the G42, but that may mean operating in the lower efficiency zones getting there. From there to 70% efficiency island on the LH side is not very wide. The G35 seems to make more sense in that regard. Over the G30 too unless you can accept a lower peak power limit.
There's also the newer G40-1000 & G40-1150 you can consider. Myself I went with the GTW3884 67mm (6765) for cost vs performance. It'll probably max out on my planned setup with a semipp.
to the best of my knowledge it hasn’t been released yet, not listed on their website either. Everything is on a slow roll out due to Covid. Their factory being in Wuhanfluville isn’t helping and is likely becoming a regrettable decision.
imo the efficiency difference is well worth the extra cost and likely not fully appreciated yet, but am understanding to budget limitations.
Thank you, I had not considered the G30-900 at all. It's fascinating that the G30-660 made 430whp at 1bar of boost.
May need to take a closer look at the G30-900 and G35-900 if i choose the 500whp option.
I was looking at the bigger G35-1050 and G42-1200 compact to see if they would be able to flow 600+whp easier without running too high boost pressures. Ideally not much higher than 25 psi as i intend to run pump fuel and water meth only.
The turbo doesn't really dictate what boost level an engine will make at a given boost level, that is dictacted mostly by the engine itself, Big variables are intake manifold and porting. Stock intake manifold likes to peak pretty low in terms of rpm 8-8300rpm even with a bridgeport or a semi pp so that will limit your ability to make power at lower boost levels. Going to a 4 barrel or projay will change that considerably.
Well that will come down to how much lag you can live with, but more importantly I think porting is going to play a lot into it as well. Because I’m not sure you can achieve that power/boost level without opening up the ports more, whether bridge, semi-P, or full-P. That’s the general trend I see, but is out of my comfort/experience level though.
So somebody else will need to guide you on that. In fact, with full disclosure at least one person on RX8Club would tell you I’m an idiot who understands nothing about nothing, but the numbers presented stand on their own accord.
The G35-1050 can get to 80 lb/min no problem and with good efficiency range. The G42-1200 is going to be quite a bit behind it on response, but likely with slightly lower discharge temp and emap. 600 whp would be dead center of peak efficiency island on the G42, but that may mean operating in the lower efficiency zones getting there. From there to 70% efficiency island on the LH side is not very wide. The G35 seems to make more sense in that regard. Over the G30 too unless you can accept a lower peak power limit.
best wishes.
Thank you, many considerations to take into account. I've currently got a Garrett TO4Z and at 1.4 bar of boost im making 400 rwhp on a large extended street port. Looks like the G35-1050 dimensions are close to my current turbo. The G42 would require a full new kit as the turbo dimensions are significantly bigger. From what you have mentioned the G35 1050 looks like the better choice for spool and peak power and I could get away with a simple a turbo swap from a much older turbo to the current platform.
The turbo doesn't really dictate what boost level an engine will make at a given boost level, that is dictacted mostly by the engine itself, Big variables are intake manifold and porting. Stock intake manifold likes to peak pretty low in terms of rpm 8-8300rpm even with a bridgeport or a semi pp so that will limit your ability to make power at lower boost levels. Going to a 4 barrel or projay will change that considerably.
Hey thank you. I'm trying to make the most of a large extended street ported setup. I understand you've had great success and appreciate any pointers. One of the reasons i was looking into a G42 1200 is because I read the your post about where you ran a GT42 at 35psi on pump fuel and water injection . Looking at the G35 1050 as well as mentioned above it will spool faster and be a bit more responsive. Do you have any pics of your engine bay?
Personally I would love going to a 4 barrel or projay setup, performance gains aside they look soo good too. Do you think they would help hold power and torque any better on a street ported engine.
Hey thank you. I'm trying to make the most of a large extended street ported setup. I understand you've had great success and appreciate any pointers. One of the reasons i was looking into a G42 1200 is because I read the your post about where you ran a GT42 at 35psi on pump fuel and water injection . Looking at the G35 1050 as well as mentioned above it will spool faster and be a bit more responsive. Do you have any pics of your engine bay?
Personally I would love going to a 4 barrel or projay setup, performance gains aside they look soo good too. Do you think they would help hold power and torque any better on a street ported engine.
A 4 barrel on a street port would move your peak power over 9000rpm. So yes it will make a heap more power.
G35-1050 can move a lot of air.
A g35-1050 on an extend port on E85 with stock intakes will need around 30psi to make 600
Same turbo , same engine, E85 with a 4 barrel will do it on around 21-22psi.
If your doing pump fuel with water injection youll need more boost to make the power with either combo.
A 4 barrel on a street port would move your peak power over 9000rpm. So yes it will make a heap more power.
G35-1050 can move a lot of air.
A g35-1050 on an extend port on E85 with stock intakes will need around 30psi to make 600
Same turbo , same engine, E85 with a 4 barrel will do it on around 21-22psi.
If your doing pump fuel with water injection youll need more boost to make the power with either combo.
Are you staging throttles on the 4 barrels or is it all at once? Seems to be a bottom end torque/flow advantage an keeping the secondary runners closed.
Are you staging throttles on the 4 barrels or is it all at once? Seems to be a bottom end torque/flow advantage an keeping the secondary runners closed.
Would also like to know. Unfortunately, only the e&j TB has the option for staging throttles but thats optional purchase, I believe the Extreme setup also had the option, but no longer available. The pro-jay TB is not capable of staging the throttles
I dont have any personal data, but my "future" tuner also said the same thing as you.
Not entirely sure the choice of going for the 1.21 v band over t4 twin scroll is a wise choice, time will tell i guess. I saw some data on a G35 900 at 16psi on a stock port and was not impressed and thought....just go for the biggest ar 1050. Do you feel the 1.06 would have been a better choice?
Well you do understand that the v-band on that is the same ID as a 2” Sch. 10 pipe, right? So you’re going to bring two of those in (one from each exhaust port) and reduce it to an undivided single one then?
Results can vary greatly for a variety of reasons. Can you direct me to what it was you were looking at? Otherwise I’m not at all questioning you choosing the G35-1050
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First, we should trust Garret a bit.
G35-1050 comes with the appropriate size 3" v-band inlet (#2 size garret v-band) that has an internal diameter of 60mm.
Second, know that V-band inlets flow more than their rectangular open volute equivalent because they have a lower cross sectional surface area to volume.
In turn, an rectangular open volute flows more than the equivalent divided volute for the same reason plus, they have a lot more cross sectional area.
Third, know that a T3 open volute housing is actually the same size (sometimes larger even as industry standards vary by a few mm) than T4 divided housing in terms of cross sectional area!
Note: cross sectional area, but listed by flow capability of housing assuming same A/R turbine housing. (Note: I was too lazy to subtract the corner radii from the T3/T4 flanges, so they have slightly less area than I list below.)
T4 open volute= ~3,800mm2
60mm ID V-band= ~2,800mm2
T3 open volute= 3,000 to 3,300mm2
T4 divided= 3,100 to 3,500mm2
So, we see 60mm inlet Vband of G35-1050 actyally flows more than T4 divided housing of the same A/R.
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Next mindblower- even if G35-1050 came with the tiny 2.5" V-band with 46mm diameter (~1,660mm2 surface area) a collector in the manifold that went from 60mm (or whatever size one deems necessary) properly tapered to that 46mm would not impact flow over the larger 3" 60mm inlet V-band as the manifold merge would be an extension of the turbo housing A/R.
I say that not just to be a self important know it all, but also point out how important turbo manifold design is.
Again; it’s a 2” Sch 10 which is 2.375” OD x 2.157” ID (54.8mm). It’s the V-band register/centering protrusion that’s 60mm. The Garrett flange diagram doesn’t show it exactly, but I know for a fact that’s what it is. It’s not far from an open T3, but less area for sure. I seem to recall a particular person in a previous G-series discussion arguing that once we thrown in the unique rotary pulse parameters then Garrett shouldn’t be trusted, but then I’m not really surprised by much these days.
The T4 divided is quite a bit more entrance area, but eventually it all tapers down to whatever the internal volute is. However, it will keep the pulses divided and complimenting each other rather than the interference and turbulence of two 2” pipes reducing to a single 2” undivided. I suppose you could weld a thin Inconel divider plate between them to help minimize that some.
Will the 1.21 make up for some of that? Maybe, but for a 2-rotor my comfort level with the divided is higher. A bunch of previous arguments on why nobody was trying these turbos was due to not having any divided options lol.
It will be interesting to see how it goes since the turbo is fairly responsive and it might be a big surprise that teaches us something. My comments are not against the selection, but rather it wasn’t the one I had expected. Because I’m not really sure what the end result will be.
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Well you do understand that the v-band on that is the same ID as a 2” Sch. 10 pipe, right? So you’re going to bring two of those in (one from each exhaust port) and reduce it to an undivided single one then?
Results can vary greatly for a variety of reasons. Can you direct me to what it was you were looking at? Otherwise I’m not at all questioning you choosing the G35-1050
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You have made some really good points. I dont know if going for the vband was a good choice but I'll test it on the 1.21 ar and report back with some real world results soon. If it doesn't flow 450rwhp around 20psi on my current setup then I will have enough data to conclude that there is a restriction somewhere else on my setup.
I saw a G35-900 make 388whp at 16psi on a stock port and thought best to go for the biggest G35 and tweak the rear ar if required. Currently looking at all the data on my old Garrett TO4Z 1.01 ar t4 twin scroll - I am making 350rwhp at 12psi, 375rwhp at 15psi and 400rwhp at 20psi....so I am hoping this new G series can flow 400rwhp on my large street port setup at a lower boost level. I mean garret claim the G series flows more air. The only thing I have changed on my current setup is my turbo...so I'll be sure to put Garretts claims of their latest and greatest flowing more air to the test. Essentially all I'm looking for is a genuine 450rwhp. Hopefully this new 1050 should get me there without working too hard.
there are some stock port EFR8374s on here doing about the same, but we all know they can do a lot better. I’m familiar with your previous TOZ4 thread as well.
There has to be something else driving that result, we can only speculate on and question based on such little information. Which 450 whp is only ~60 lbs/min and that compressor has 750 whp potential, a bit more than a BW SXE369. I don’t think you have to worry about pushing it, especially with a 30+ lb/min turbine housing.
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there are some stock port EFR8374s on here doing about the same, but we all know they can do a lot better. I’m familiar with your previous TOZ4 thread as well.
There has to be something else driving that result, we can only speculate on and question based on such little information. Which 450 whp is only ~60 lbs/min and that compressor has 750 whp potential, a bit more than a BW SXE369. I don’t think you have to worry about pushing it, especially with a 30+ lb/min turbine housing.
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I am running a HKS cast mani, 3"DP with wg plumbed back into the dp and a 3.75" exhaust system. I suspect the 3" dp could be a potential restriction but like you said we can speculate on why the old to4z did not flow enough for 450rwhp. However, the only change in my entire setup will be the turbo, so the results will certainly be interesting. Hopefully the G35 flows more like Garrett advertise! I know the piston guys are raving about the G35 1050 but no idea how well that will translate over the a 13b.
06-13-21, 10:38 AM
. Looking at the G35 1050 as well as mentioned above it will spool faster and be a bit more responsive. Do you have any pics of your engine bay? 
lol.