[TurboGT]

As many of you know, i've advocated for the Garrett Powermax turbo since I found out about it from SEMA 2019. It caught my attention with Garrett reliability, Factory interchangeability, and (at the time) a promise of a 20% power gain. It sounded like everything I could ask for. Simple part replacement as well as factory reliability and what I assumed at the time would have been a power figure into the 300s on a conservative tune. Well, May 2021 came around and it was finally here so I picked one up as soon as I could.Now that i've completed a second round of tuning, I figure i'd post up about my experience for others to see.

First impressions: The turbo is still tiny like stock. However, the compressor housing is around 1/2” larger than stock so its a noticeable size improvement along with the advertised 52mm compressor wheel increase. It comes with a plastic bypass valve, which it's highly recommended you upgrade this unit (it uses a Focus RS unit). I installed a Ford Performancew one. When I had the BPV out I had a look at that nice GTX cnc machined compressor wheel. Looks solid!

Installation: You dont need a how-to. This turbo dropped in just like stock, zero fitment issues.

Driving: This turbo has factory characteristics. You won't be able to tell the difference other than an increased overall power level that parallels the stock k03. It does make some really cool noises though, and i'm using a factory closed airbox! I'm sure this thing would make some killer sounds through any of the hot-air intakes on the market.





Power: Prior to this turbo i have only run the factory tune, with stage 3 hard parts. So overall this was a large jump in power for my situation. Here's where Things get dicey, though. First off, there is a boost dip that occurs immediately after the wastegate opens. Whether you run the stock Garrett wastegate actuator, the Garrett wastegate actuator with more preload, or the Turbosmart Wastegate actuator with 7psi spring, the dip is still there. I think it has to do with the large difference in wheel size between the compressor and turbine, and how greatly the shaft speed reduces upon opening the gate. A large hot side and larger turbine wheel would have helped this unit in a multitude of ways. You can feel the power delivery momentarily drop when this dip happens.
Secondly- the overall output. This thing will absolutely maintain north of 20psi up to 6500rpm. While this sounds nice, the engine had ignition corrections above 8.5 degrees of timing. Due to this, the power had a sharp nosedive over 5500 and It did not feel great to drive, the power dropoff was worse than stock. During the second round of tuning I suggested that maybe the hotside is so restrictive that we can make more power using less boost and more timing. Alan agreed and started boost at 22, tapered it to 15psi by 6500, and ended up ramping up to 15 degrees of timing by 6500. Vdyno confirmed on several runs, this showed a solid 30hp 20tq gain from 5500 to 6500 and very noticeable seat-of-the-pants difference in acceleration. I'm much happier with this output now.

Here's a comparison of the Final tune with sustained high boost (red line), versus the final tune now, with tapering boost and more timing (blue line):

Heres a comparison of The two best vdynos. The higher torque vdyno (blue line) was on a 50 degree morning, the lower torque (yellow line) run was today, 65 degrees outside.

Here is Stock (green line) versus todays run (yellow line):

So with a Conservative 93 octane tune thats easy on the torque, Im around 285whp, 330 wtq on average. I'm sure with some more aggression in the tune it would be 300hp. I had planned to hold off and get this thing on the rollers before posting numbers, but that seems to keep getting pushed back and i didnt want to keep you guys waiting, so vdyno will have to do until that time comes.

e30 numbers are 321/358. Runs fantastic on the blend.



Some important notes:

• This turbo uses a focus RS bypass valve. Its highly recommended to switch the stock plastic unit out due to the boost levels being run. I used the Ford Racing bypass valve. I personally recommend a bypass valve over a blow off valve as it helps keep the turbo spooled better through gear changes by dumping the pressurized air back into the compressor inlet. Besides, if you want the noises, this turbo makes plenty of induction sounds and bypass noises.
• This turbo also uses a focus RS wastegate actuator. It is diffferent from the ST unit, and I had to machine the shaft of my ST unit and shorten it to accept a clevis to attatch on the Powermax
• With the above being said, I do NOT recommend changing the wastegate actuator since this turbo only responds well to a downward-sloping boost curve anyway. Its a waste of money.

All in all, whether i'd recommend this turbo or not depends on your personal situation. Horsepower per dollar it's on par with someone changing their car from stock to stage 3 ( 20whp for 1500 dollars total). Because of that I'm categorizing this as Stage 4, as it is NOT a big turbo nor makes big turbo numbers, but more or less is just another incremental step in power before jumping off the deep end into huge horsepower aux fuel and built motor territory. It drives just like stock in every way and will not change how the car responds with the exception of more horsepower. If you're looking to spice up your commute and not lose any of the stock turbo snap or stoplight-to-stoplight performance, this guy is for you. If you want to be a highway star and see how fast you can do 40-120 rolls, this is not your turbo. It fell slightly short of my expectations regarding power delivery. I was hoping to make 300 reliably on 93 octane, but unfortunately you would need to ride a fine line to get that with this turbo.



EDIT: finally made a video showcasing the sounds this turbo makes.

EDIT: Full throttle e30 Acceleration

 

[Duece McCracken]

Sounds slow...

The torque is waaaay lower than a K03. Which is interesting.

Glad to see you do something to your car. Lol

Great info!

 

[TurboGT]

Sounds slow...

The torque is waaaay lower than a K03. Which is interesting.

Glad to see you do something to your car. Lol

Great info!

The torque could have easily been higher (panda achieved 400wtq on pump gas). It was intentionally reserved. Doing burnouts isn't cool when you're trying to accelerate though. This entire venture was mainly for better top-end power. While it didn't really broaden the graph, either, its still much more fun to drive than before and is a large improvement on the highway.

 

[ryno9100]

As someone looking to keep my car as reliable as possible, while increasing the "stoplight to stoplight" performance, as you put it, this sounds like a no-brainer. I don't want to deal with aux fuel or mixing gas. I have a hard enough time convincing myself to put 93 in it some days (though, I've never put anything but 93 in it since I got it).

Thanks for the write-up! I was just mentioning in another thread that I couldn't wait to see more and you definitely gave us more. I assume you were running all of this on your already existing stage 3 setup?

 

[TurboGT]

Thanks for the write-up! I was just mentioning in another thread that I couldn't wait to see more and you definitely gave us more. I assume you were running all of this on your already existing stage 3 setup?

I had stage 3 hardware, but stock tune this entire time. The 3rd vdyno graph shows where i started and where i am now.

So i just added the turbo and tuned for it at this stage.

 

[Habriant40]

Nice write up! Looking like 50 whp over stock by Vdyno comparison. Which is excllent - roughly a 20% power increase

Now for some water meth.
But don't increase your timing.. Increase your boost.

On second thought.. Maybe enjoy the fruits of your labor for a while

 

[davesST]

@TurboGT Who did you go with for tuning purposes? I’m fairly low tech, so if I went with this unit I’d like to get with a tuner who has some experience with this turbo. Given some of the past posts from some, I’m not sure I’d want to use Panda.

 

[TurboGT]

@TurboGT Who did you go with for tuning purposes? I’m fairly low tech, so if I went with this unit I’d like to get with a tuner who has some experience with this turbo. Given some of the past posts from some, I’m not sure I’d want to use Panda.

I used Alan Jackson at Edge autosport. He told me that they have one of these units they will be installing on their otherwise Stock ST shop car, and as he gets a bunch of time on the dyno with it, if he finds more refinement in this turbo, he will update my tune accordingly.

@Habriant40 Yeah its a pretty good jump. I esitmate 20hp over a tuned stage 3 k03 car, which again, is about all the power you get when you go from stock to stage 3. Nevermind the torque, this isnt a tow rig.

@Joe007 forgot to mention, here is the review you were looking for.

 

[MonsterTuned]

@STallion18 just purchased a dyno tune for his powermax so I'll have it on the dyno here to see what my results are with it. The dyno I use had my 2021 GT baseline 423 whp and 478 whp with e85/headers on our tune. It gives pretty standard 12% drivetrain loss results with SAE correction.

I'm expecting 300whp on 93 octane or at least that's my goal so we'll see. We used to do 325whp on 93 and 360whp with our hybrid turbo on e30, but we discontinued them due to not wanting to sell parts anymore.

 

[TurboGT]

@MonsterTuned keep us all in the loop when you get his dialed in. Ultimately the dyno will be a place to get the necessary feedback on where this turbo will be happy with boost and timing.

 

[Joe007]

Thanks for the review.
I was really thinking of going with this turbo. But now I will hold off to see more reviews.

 

[Habriant40]

I'm expecting 300whp on 93 octane or at least that's my goal so we'll see. We used to do 325whp on 93 and 360whp with our hybrid turbo on e30, but we discontinued them due to not wanting to sell parts anymore.

Aw mann.
Such a cool project and product. Wish I had $$ when I did my turbo replacement. Bummed to see them go.
Makes sense with all this hype for Garett powermax and such. Still the most powerful hybrid. Very impressed

 

[Thieske]

So if i understand correct;
you dont actually know how much more hp this turbo makes? you went from stage 0 with bolt on parts and now turbo straight to stage 4 and gained approx 50hp?
My car was stage 0, I added bolt ons but kept stock turbo + got it on rolling road for new map = also got +50hp (+52 actually).
Not to downtalk your efforts, but this would have been a better comparison if you were fully tuned and then added the turbo + got it remapped

 

[STallion18]

No doubt you can go 302 crank hp on stock turbo with bolt on's and tune, pushing the stock turbo to the limit and creating a time bomb in the process. With this new turbo the philosophy is reaching around 300 wheel hp in a relative safe and reliable way. It's not a big turbo by any means, it keeps the stock turbo daily manners with a better upper end.

 

[beretta96]

So if i understand correct;
you dont actually know how much more hp this turbo makes? you went from stage 0 with bolt on parts and now turbo straight to stage 4 and gained approx 50hp?
My car was stage 0, I added bolt ons but kept stock turbo + got it on rolling road for new map = also got +50hp (+52 actually).
Not to downtalk your efforts, but this would have been a better comparison if you were fully tuned and then added the turbo + got it remapped

The thing with the Powermax isn’t so much the final horsepower number as much as it’s the way it gets to that number.

You’re spot on with your assertion that someone can get ~290hp with a tune the same as getting to ~290hp with the Powermax; however, the Powermax gets you to that ~290hp target with less cylinder pressure and stress on engine internals - it’s a ‘softer’ 290hp so to speak.

You’re correct that dollar for dollar there is a cheaper way to get an ST to ~290hp - just go get a tune like folks have been doing for years.

However, with the Powermax, for an additional ~$1200 and some wrenching, you can get to 290hp with less stress on the engine and a lower risk of having to add to the ‘Blown Engine’ thread.

 

[TurboGT]

@Thieske didn't you make 300 brake horsepower? This turbo is capable of 300 wheel horsepower, so approx 330BHP. i have a conservative tune so i am 10 to 15 shy of that.
The stock turbo is only capable of these numbers on ethanol, anything saying otherwise is a falsely-reporting dyno. There are pretty well-documented hardware limits with these cars.
Also, see @beretta96 's reply above.

 

[SSgtjrobertson]

To @beretta96 point. It's less to do with big power and more to do with producing more power with less overall strain on the engine and related components. While this unit does fall short of it's original expectations it will be a vast improvement over the factory equipped K03.

 

[ryno9100]

To @beretta96 point. It's less to do with big power and more to do with producing more power with less overall strain on the engine and related components. While this unit does fall short of it's original expectations it will be a vast improvement over the factory equipped K03.

The fact that it's a direct bolt on will be a big win for a lot of folks, myself included. I want things as simple as possible. No added piping, no need for extra setups, just take one turbo off and put another on.

 

[Habriant40]

Cheapest way to consistent 300 whp is the BWS. 🤪
probably the most you can do with the k03 turbine. Everything else moves up to a K04 or more

 

[junits15]

So if i understand correct;
you dont actually know how much more hp this turbo makes? you went from stage 0 with bolt on parts and now turbo straight to stage 4 and gained approx 50hp?
My car was stage 0, I added bolt ons but kept stock turbo + got it on rolling road for new map = also got +50hp (+52 actually).
Not to downtalk your efforts, but this would have been a better comparison if you were fully tuned and then added the turbo + got it remapped

This unit will theoretically be more reliable at the same power level. It’s a smarter way to get that power.


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