Gee Cee

Hi all

Has anyone had driving experience yet with the Garrett G40-1150 with a manual gearbox? The reason I ask is I'm looking at upgrading to one of these but I am a bit concerned that it may be laggy without a convertor to bring it on.

The motor is bridgeported and also has quite a large exhaust port. Will be switching over to E85 and be aiming for roughly 600HP and only be used on the street here in Australia.

Feel free to also suggest similar turbos that may be a better option.

rx7srbad

Have a chat with omar at race only, think he's posted a some results with a g40 1150 1.19 ar on his insta. Let me know what you find in regards to the response. I'm very interested in this turbo as well.

BLUE TII

iTrader: (9)

G40 is not an overly large turbo for a bridgeport 13B.

As indicated above we have real world results from Raceonly.

You can see from the Raceonly dyno the bridgeport G40 with 1.19AR hits full 25psi boost ~4,500rpm.
200hp by ~4,200rpm and 300hp by 4,750rpm peak power 650hp/493ftlbs

That spool is like an old streetport T04Z set-up which you are probably familiar with.

Im not saying you couldnt make 600hp on a G35 with better response (you most definitely could with EFR 9180). Just that G40 would spool easily enough for drag racing on standard manual gear ratios.

TeamRX8

iTrader: (2)

just pointing out that his assessment on the two turbos used on that dyno graph is incorrect

because as I’ve neen trying to explain on here for the last several years, the actual turbine flow potential is the number that matters more than A/R value between either two different turbos or two different frame sizes

because the flow potential of the G42 1.05 turbine (~45 lb/min) is higher than the G40 1.19 (~42 lb/min)

so if rotaries love more turbine flow as stated then the G42 would win, yet it doesn’t

demonstrating that why the results are what they are is not understood by the commenter
.

BLUE TII

iTrader: (9)

Regarding the text of Raceonly"s post.

If one does the math I believe one will find the 79mm compressor g42 1.05ar has a smaller exhaust to compressor side bias than the 71mm compressor G40 1.19ar.

A dyno test of a hybrid 71mm compressor G42 1.05ar would be required for a direct comparison.

BLUE TII

iTrader: (9)

His dyno comparison shows that a smaller turbo with a larger exhaustd side to compressor side ratio can make as much power as the next size up turbo with better spool and response.

As in, rotaries prefer larger exhaust side turbos.

rx72c

iTrader: (8)

Is this derived from your real world testing?

I have said it before and I will say it again, you can theorise all you want but you have not tested any of your theories and when you do, you will quickly find out your foundations are flawed.

I have done a large amount of testing over the years and while I may not be perfect and I may get it wrong from time to time, you cannot argue with the results.

Based on what I've seen on the garret website my test was fair, I paired up two turbos with very similar exhaust flow and showed that we could make the same and in this case MORE power with a smaller compressor wheel

I did the same with the G45 vs G42, we made 60 more HP going from a G42 to G45 on the same boost (Although to be fair the G45 flows more on the back here) but we saw more HP and 4-500rpm faster spool, there were 0 cons going to the 45

I wonder why.... We could theorise all day long but they are just theories. I tend to look for patterns and trends that are repeatable in the real world and begin to build a foundation of knowledge from that

Your information is based on absolutely nothing except other peoples work which you then combine together as if they are equal some how lol

Testing requires so many control variables and you throw that out the door when you sit there keyboard analysing dyno sheets and flow maps

When you have actually finished some real world back to back testing and done the work, maybe then you will have something valuable to contribute.

rx72c

iTrader: (8)

I have done over a dozen G40-900 and G40-1150 with both Street ports and Bridgeports in a manual.

I have made 650rwhp time and time again on 24-25PSI on a Bridgeport with a G40-1150 1.19 housing

Powerband is 4500-8500 in 2nd/3rd/4th gear, 1st gear you'll make that boost by around 5000

All of those cars are using twin scroll housings and twin gates which helps them make boost earlier than the single entry vband housing(I did a back to back on a track car from vband to T4 twin scroll/twin gate and boost was much more linear and came on around 500rpm earlier), don't recommend single entry housings for a 2 rotor (we are making 10psi by around 3800rpm on the twin scroll setup)

Gee Cee

Given your experience, would the G40-1150 be your turbo of choice for that 570 - 670hp range but still responsive enough to enjoy on the street?
have you done any testing with a 1.06 rear housing? Would it make it much more responsive? And would it significantly hurt the top end power?

Either way I'm sure it's an improvement on the 20+ year old Garrett turbo that is currently on the car (which I dont even know what it is)
It has 2 numbers to identify it :
S/N - GI 6019J
GTI P/N - 704484-5

Can anyone tell me what turbo that actually is? It's been suggested that its part of the gt42 range from around 2001 but cant find anything to confirm this.

Thanks

Gee Cee

Double post

Slides

Google agrees, https://www.ausrotary.com/viewtopic.php?t=225598 , they were well regarded for making power and being more responsive than the T series and not too different to to4z despite the greater power potential if I remember correctly.

Ideally you would get major and minor compressor and turbine measurements to identify it but just the compressor if it's actual Garrett will probably let someone identify it with that other number.

I think people still aren't comprehending you need a good match between compressor and turbine shaft speed wise for them to work well, the G40 seems to be well matched in that regard.

rx72c

iTrader: (8)

they are an excellent turbo for the street

The 1.06 will not make the peak power you're looking for but it will make it a little sharper coming on boost.

In my mind id rather loose the 2-300rpm down low to gain another 800-1000rpm up top at higher boost levels and again in high horsepower street cars you want a more linear boost ramp and in a twin scroll config with the large 1.19 housing you get a nice smooth boost ramp which makes for a much faster car, less wheel spin etc (This is more personal preference but you can choose to whichever way you like)

rx7srbad

It's amazing the results with the G45. Was this on a big Bridgeport engine? What kinda boost level were you at? and can you advise what rear housings were used on both turbos? Fascinating that the spool was also faster on the 45.

rx7srbad

What sort of power are you seeing with the G40 1150 street port builds?

I gave up some boost response on my g35 1050 going vband. Do you use custom fully divided twin scrolls setup? would a twin scroll with a single gate impact boost response you rekon?

Gee Cee

This makes sense, you dont want to run out of legs once you break through the wheel spin.

Which workshop are you from? I'm based in NSW.

Howard Coleman

iTrader: (6)

" in high horsepower street cars you want a more linear boost ramp and in a twin scroll config with the large 1.19 housing you get a nice smooth boost ramp which makes for a much faster car, less wheel spin etc"

linearity in all aspects (handling as well as acceleration and braking) cannot be over-emphasized. unless you have driven, really driven a 500+ rwhp FD you cannot appreciate how violent the accel is. in order to manage it, it needs to be linear.

i did a hot side housing comparison a few years ago. SXE-62 .91 and 1.0. i found the 1.0 produced about 60 F less EGT and 4 psi less backpressure. both made good power, over 500, at 8800 w an optimized raceport.

a 13B should be considered as having a similarity to a two piston motor. when one piston/rotor is at TDC the other is at BDC. a properly designed UIM, such as the OEM item but there are other race manifolds that use the same design concept, uses a "U" shape connecting the two rotors. this takes advantage of violent pressure waves from the closing port. an "opposite and equal reaction" helps fill the opening port. i unfortunately proved this communication between the 2 rotors when i broke a ceramic apex seal in one rotor and the material did a really good job of totally wrecking the other rotor housing.

on the other side of the motor, the lack of slower closing valves, the PERIPHERAL nature and size of the exhaust port, and the fact that the flow is not smoothed by a larger number of impulses all delivers an exhaust stream that really needs to not be diluted by combination.

in other words, do NOT run a V band.

as to general power of the G40-1150... i am just getting acquainted w it, running off the spring at 15.9 psi. i am seeing 536 rw. i have a 1.06 back end. backpressure crossover is 350 rpm later than my EFR9180 and remains lower. i look forward to getting into higher boost.

Slides

Raceonly

rx72c

iTrader: (8)

What dyno are you using?

rx72c

iTrader: (8)

Fully divided, twin scroll with single gate might as well be vband

The street port builds as always just require more boost to make the same Peak HP since they peak at a lower RPM (around 76-7800 instead of 84-8600rpm) and that really depends on the street port itself. Some of them don't really make much more grunt than a stock port.

Instead of making 650@24-25psi on a bridge, we are going to 30-31psi to make it that on a street port the power curve is not as wide. This is all on OEM intake, if your using a Projay Tyhpoon or Bully this dramatically changes the peak power RPM and that changes all of the above.

rx72c

iTrader: (8)

It was a Semi PP with a Typhoon intake

Boost was at 28-30PSI

1.28 housing used on both

Same car, same engine less than 1 week apart

I can't say exactly why it spooled faster, I have a few theories but they are just that. After that back to back on the G45 I have opted for the smaller compressor on a few other turbo combinations and they have all seen faster spool. Obviously smaller compressor would mean faster spool, but on that G45 test you would have thought that the larger turbine wheel would offset any gains in spool from the smaller front, it seems clear that the compressor has more say on spool characterisitics than the turbine does? Maybe someone more knowledgable on turbo tech could explain it. Looking at turbo manufacturers, we can see a clear trend change in turbo configurations, smaller compressor wheels and large turbine wheels is becoming more and more popular. G40,45,47,50,57 have all seen many additions here with significantly small compressor wheels in relation to the turbine wheel. Even precision are doing more in this department as well.

rx7srbad

Absolutely fascinating, and thanks for sharing your experiences and insights. I'm unable to explain the spool of the G45, I'm afraid I have even less experience with turbo tech on 13bs.

I recently discussed turbocharger specifications with my engine builder, Tim. We talked about the T51r Kai and T51r SPL models, which were used on his drag car over a decade ago (the latter turbo running a 8.3s 1/4 mile). His Semi PP still runs the T51r Kai and he mentioned it uses a 92mm compressor and a 71.4mm turbine, while the T51r SPL has a larger 102mm compressor with the same 71.4mm turbine. Quite the contrast in turbine sizing on the current G series line up you mentioned.

I'm no turbo tech expert but for my own benefit I tried to find some kind of reference with the old T51s to the current G series line up. Correct me if i'm wrong but the old skool T51r's 94mm and 102mm compressor falls into the mammoth G55 turbo range. Big boy turbos!! Wonder what R&D HKS did with those comp/turbine numbers.

Slides

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Download an old Garrett catalogue, the HKS turbos are basically Garrett compressors and turbines with lighter housings. Wheel major/minors match, I can't recall exactly but it was only around gt42 or 45 size wise from memory.

BLUE TII

iTrader: (9)

71.4mm being the minor diameter of the HKS T51R.

HKS T51R exhaust wheel is 82mm major diameter and 71.4mm minor diameter turning a 70.3mm/94mm compressor wheel for the "800hp" Kai spec and 76.5mm/102.2mm compressor wheel for the "1,000hp" SPL spec.

rx7srbad

I'm getting confused here....explain the above like I'm a 5 year old...haha!

so a G35 is a 68mm comp / 62mm turbine ...would drag racers call this a 68mm turbo?
the G40 1150 is a 71mm comp / 70mm turbine? so this is a 71mm turbo?

what is the HKS T51r Kai in relation to the above?
kai - 70/71
51r spl - 76/71.4?

rx7srbad

To me this sounds far more reasonable.