When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
When I looked at the V2 options it looked like G40-1150 or a jump to the G45-1500 or 1600 was probably still the best balanced compressor/turbine couples for our use in terms of efficiency, possibly a little bit of boost threshold available on the higher flowing smaller GXR inducers if you are willing to give up a few percent pumping efficiency in the top end.
The G40-1150 is undoubtedly a solid choice. I may well regret not getting this turbo. It has delivered many proven results, making it a go-to option.
For higher output setups, the G45-1500/1600 appears more oriented towards drag racing. While powerful, I think these turbos might lack mid-range response. Nath's G42-1200 ran an impressive 4.89s 100-200 km/h, but the turbo showed limited power below 6000 RPM. Unfortunately, he forgot to record the dragy video overlay so i couldn't add it to the leaderboard. He has run over 10 low 5s 100-200 passes consistently which was verified with the report and the video overlay. I'll update the leaderboard soon. It's a very impressive result on pump fuel and water injection.
The G45-1125, is my pick with its 67mm compressor and 82mm turbine because it closely resembles the Precision 6885 turbo that Omar runs. While the Precision has shown strong performance, I suspect the Garrett G45-1125 would be more responsive while achieving similar power levels. Of course, this is speculative, and real-world results would provide valuable confirmation.
Another intriguing option for me is the new GXR 42-68.9. Its 69mm compressor and 75mm turbine size closely resemble a 69/75 Precision turbo but benefit from Garrett’s renowned efficiency.
As you pointed out, there are excellent turbo options in 2025.
For now, the G40-900 is my speculative pic. Fingers crossed it does well compared to its bigger sibling. We all love a good under dog story !!
i can't be of much help on spool rate as my WG is set at 19.5 Duty Cycle. i could significantly improve spool if i were to change to a higher DC.
Howard, are you running open or closed loop boost control with your Link? If using open loop, you might want to try out the closed loop boost control - I've found it works wonders for improving spool on mine, especially if you've already got a well-sorted open loop boost control tuned.
the last 100% TPS data point on my most recent run (8008) showed 22.0 boost and 30.2 back pressure 37%. at just over 600 rw/80 pounds air.
on that log i had more boost than backpressure until 6500.
4 inch DP, 3 inch exhaust, WG plumbed into DP., Borla mid muffler, Racing Beat single tip catback.
i can't be of much help on spool rate as my WG is set at 19.5 Duty Cycle. i could significantly improve spool if i were to change to a higher DC.
starting at the point where i first was at 100% TPS (4316/12.9 psi) the log shows it took 1.081 seconds to go to 22.0 psi/5185. third gear.
The 1150 T4 1.06AR shows better response compared to the G35-1050 V-band 1.21AR. The logs indicate 22 PSI at 5300 RPM in 3rd gear, though EMAP data isn't available.
Will get to 26psi on the G35 1050 and see how it does. Then move onto the G40 setup which should be interesting.
there is something to be said for a boost "curve" rather than an explosion especially for my current turbo. whereas it might be fun to be at 16/20 on an 8374 around 3500 it wouldn't be fun w my G40-1150. i recall one time having the hoses reversed and i was above 30 psi before the pedal reached BDC. no way to control that. w my current wastegate springs i am around 450 off the spring with zero creep. around 600 at 19.5 duty cycle and 31 psi at 32.5 duty cycle. yes, i am wastegating lots of flow but operating around 77% efficiency.
i see zero creep anywhere in spite of my (purposely) disadvantaged wastegate location. (single Tial 60) i also notice less than 2 pounds decrease at redline w a constant duty setting. true at 20 or 30 boost.
Your approach to boost control with the G40-1150 is well-tuned for drivability. I do similar for the 1050 to keep it progressive and linear. Depends on application of course but max response with zero traction is a slower car, Spinning's not winning!
If you get a draggy, would be good to see a 100-200 or similar to compare data.
my test roads have a bit (unknown) of slope to them. i will not be doing the typical 100/200 - 1/4 mile but will use it for tuning in 3rd gear... around 70 to maybe 120. i have read that if the slope isn't within X the run is DQ'd. i can understand that if the data is being used for some larger leader board type of situation. my question is, will the data still be logged and available if there is slope outside the normal parameters.
my current plan for my mile run will be to use my I phone hooked to dragy to get a vlog with speed distance and the view out the front window.
my test roads have a bit (unknown) of slope to them. i will not be doing the typical 100/200 - 1/4 mile but will use it for tuning in 3rd gear... around 70 to maybe 120. i have read that if the slope isn't within X the run is DQ'd. i can understand that if the data is being used for some larger leader board type of situation. my question is, will the data still be logged and available if there is slope outside the normal parameters.
my current plan for my mile run will be to use my I phone hooked to dragy to get a vlog with speed distance and the view out the front window.
what is the best place for the dragy module?.
Try doing 60mph -100mph, should be a fairly easy 3rd gear pull in a stock fd box.
If the slope is negative -1 degree the result will be invalid but it will still record a time.
He's gone faster since, upping boost to 32psi and running a 4.91s 100-200km/h on pump fuel and water injection. However, he forgot to record the run with draggy overlay. So his time of 5.18s with video overlay and report goes on the leaderboard. That being said 5.18s - 4.91s on pump fuel and water injection is an insane time demonstrating incredible real world acceleration. Well done guys!!
The G42 setup looks like an obvious upgrade path for many FD owners who desire faster acceleration than a G35-1050/G40-900/1150 streetport. It will be very interesting to see how the smaller siblings compare. Watch this space.
Nath ran a 4.91s 100-200km/h but due to the video overlay not being recorded...its not able to go on the draggy leaderboard at this time. Once again, an impressive feat on pump fuel and water injection.
Better late than never, RX7 13B 100-200km/h Leaderboard updated below.
We now have verified Dragy results for a G42 1200C and G35 1050, allowing us to make some calculated estimates for the G40 900, which sits between them.
G42 1200C 73/75 (Nath's Setup): Verified 4.91s (32 psi) and 5.18s (29 psi) 100-200 km/h times show that this turbo excels in top-end power breaking into high 4s range for the 100-200km/h sprint.
G35 1050 68/62 (my setup): At 5.98s (23psi), lacks the airflow to compete with the G42 at high speeds but offers quicker spool and better low-end response. Even with more boost, I suspect it wont break into the low 5s. However, I will try my best to push 30psi to see how it performs in the real world. However, I suspect there will be diminishing returns.
G40 900 62/70 (Projected Performance): Given its mid-range size, I estimate 100-200 km/h in the 5.3-5.5s range at similar boost levels. It will spool faster than the G42 but won’t match its outright power.
The data confirms that G42 dominates top-end performance, while G35 is better suited for quicker response. My thoughts are the G40 900 should provide a balance between the two, making it a strong contender for both spool and high-speed performance. This turbo has a lot to live up to now and hopefully gets into mid to low 5s range.
At this point I doubt the G42 will be able to reach mid to low 4s without tapping out. The trend suggests a G45-1125 67/82 which closely matches Omars 6885 is the ticket for low 4s range if choosing from the Garrett Catalog.
I think the G40-1150 is a brill turbo - I think it will be a touch faster than the G40 900 in the real world due to its larger compressor 71mm vs 62mm of the 900 but turbine-limited as both turbos share a 70mm turbine.
Take it with a pinch of salt as I've put the G45-1125 and G40-1150 into the below table for projected performance.
log shows slightly higher EMAP after 8132 which is the backup pressure after the throttle closes
1.06 back end
Is that power figure based on an airflow model, fuel flow model or a maths channel of vehicle mass, rolling resistance, wind resistance and inertia?
Edit: I'll add I did validate a list of equation Sneaky Pete AKA Rice Racing posted in Ausrotary.com years ago that he was using on a maths channel on his Vbox years and years ago that should have been pretty accurate for wheel power on the FD3S chassis, you may be able to foid that information if you want to generate a simulation maths channel.
Nice! What size a/r turbine housing? 1.06?
Would this be ok in a semi p or is the 1.19 better suited to keep exhaust reversion lower?
For a semi-PP, which makes peak power higher in the rev range you’ll want as much turbine flow as possible. A 1.19 A/R will help the engine breathe freely and keep EMAP as close to 1:1 as possible, reducing exhaust reversion. Since these engines thrive in the top end, the larger housing will allow for better efficiency and maximum power without restriction. The 1.19 is the better choice, imo.
I'm gonna be running a G40-900 with a 1.19 A/R on my 13B street port with a Turblown UIM to maximize airflow and keep EMAP as close to 1:1 at my 8000-9000 RPM redline. I can only imagine a semi-PP would want to rev even higher. What’s your redline on the semi-PP?
Ultimately, it will come down to your personal preference, application plus any input from your tuner and engine builder.
!!
