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Old 11-04-2020, 08:58 AM   #1
Barge
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Default EFR vs G Series Turbos for Track Use

So I'm working toward making my Forester a legitimate "competitor" (The car at least... me behind the wheel is another story) and as part of that I've got to up my power level considerably.

I've got plans on components to put together a long rod ej22t and i'm trying to decide if I want to get on the garrett or BW turbo train. Since they seem to focus along considerably different turbo inlets once I go one way i'll be a little stuck without doing a bunch of fab rework.

Dyno charts are one thing but they don't really cover how well the turbos respond to transients and general on track performance.

The EFR 8474 seems to be the turbo to go with these days in Gridlife Streetmod and I like the potential packaging of mounting the divided T4 with IWG in a low mount location. Saves a ton of expense and piping trying to do a decent twin scoll EWG setup. This does bring me back to fully committing from a fab side of things.

Does anyone have a compelling argument to use a G35-900 or something along those lines over a 8474?
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Old 11-04-2020, 10:39 AM   #2
subydude
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The only argument I've seen for using the G series is they have a more efficient compressor wheel due to the way it's manufactured.

Both the G series and B2 housing of the EFR's seem sensitive to over speed issues on the turbo, so running a speed sensor is a good idea. However, I know the EFR went through revisions to prevent that and the issues "seem" to be mostly behind us. Conversely, I know of 3 people right now that have gotten bad G series cores, or had issues with over speed that shouldn't have happened (as in, they really weren't off the map).

The cliff notes is G series will make slightly more power, but have slightly less response in comparison to the EFR. The EFR is definitely more proven at this point, and a LOT of people like them (including me). Were it me picking a track turbo, I'd get a 7670. The 8474 will have more power potential, but the 7670 will give a broader power band with a bit more oomph out of corners so you can be lazy and not have to shift as much.
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Old 11-04-2020, 12:46 PM   #3
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I never had a chance to get onto a G series, but FWIW my GTX3076R Gen2 had me being very competitive in GTA Street Class throughout 2017-2018 with track records at Buttonwillow CW13, WSIR, Streets of Willow, Road Atlanta, NJMP, Cal Speedway + Infield.

My setup was Tomei ELH, ETS rotated kit, all Vband. Never had to worry about turbine speed issues or the like. It made great power (580whp @ 34psi), which I never even used. I ran it primarily at 540whp and had excellent results.

I would talk to Mike Aumick, he picked up a G25-660 which was one of my GFs spares that went unused, and both he and TiC were impressed with the gains / differences between that and his prior Gen2 GTX setup.
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Old 11-04-2020, 02:03 PM   #4
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Quote:
Originally Posted by subydude View Post
The cliff notes is G series will make slightly more power, but have slightly less response in comparison to the EFR. The EFR is definitely more proven at this point, and a LOT of people like them (including me). Were it me picking a track turbo, I'd get a 7670. The 8474 will have more power potential, but the 7670 will give a broader power band with a bit more oomph out of corners so you can be lazy and not have to shift as much.
I run a standalone and will, regardless of choice, be integrating in a turbo speed sensor.

I've considered the smaller turbo as well because quit frankly i'm not sure I trust myself with 8474 levels of power...but I also don't want to feel like a need to upgrade the turbo in a year (although honestly it's kind of a big step in motor build cost to truly be able to take advantage of the bigger turbo).

Are you using an external or internal gate? I know there's a thread in power bragging where people are using the internal and having different issues but if it flow sufficiently it would seem to be the way to go.
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Old 11-04-2020, 02:04 PM   #5
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Quote:
Originally Posted by kos View Post
I never had a chance to get onto a G series, but FWIW my GTX3076R Gen2 had me being very competitive in GTA Street Class throughout 2017-2018 with track records at Buttonwillow CW13, WSIR, Streets of Willow, Road Atlanta, NJMP, Cal Speedway + Infield.

My setup was Tomei ELH, ETS rotated kit, all Vband. Never had to worry about turbine speed issues or the like. It made great power (580whp @ 34psi), which I never even used. I ran it primarily at 540whp and had excellent results.

I would talk to Mike Aumick, he picked up a G25-660 which was one of my GFs spares that went unused, and both he and TiC were impressed with the gains / differences between that and his prior Gen2 GTX setup.
Based on my reading I thought people generally considered the g25-600 a little bit of an underperforming turbo on subarus... but it is the interwebs so it's hard to find real data.

What A/R turbine did you use?
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Old 11-04-2020, 02:53 PM   #6
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Quote:
Originally Posted by Barge View Post
Based on my reading I thought people generally considered the g25-600 a little bit of an underperforming turbo on subarus... but it is the interwebs so it's hard to find real data.

What A/R turbine did you use?
I can't remember if it was a G25 or G30 to be honest. Might have been G30-660?

I had a small .81 on my setup. Made great power, usable too. Was trapping 146mph into Sunset corner before the start finish straight @ Buttonwillow.
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Old 11-04-2020, 04:24 PM   #7
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Quote:
Originally Posted by Barge View Post
I run a standalone and will, regardless of choice, be integrating in a turbo speed sensor.

I've considered the smaller turbo as well because quit frankly i'm not sure I trust myself with 8474 levels of power...but I also don't want to feel like a need to upgrade the turbo in a year (although honestly it's kind of a big step in motor build cost to truly be able to take advantage of the bigger turbo).

Are you using an external or internal gate? I know there's a thread in power bragging where people are using the internal and having different issues but if it flow sufficiently it would seem to be the way to go.
I have an internal gate. It's enough on a 6758 to make 425 whp and 475 wtq on a dyno that reads 2008 STi's as 205 whp. The EWG would make more power, but for what I do the IWG solves most problems and is so easy to package. The turbo is on the ragged edge since it's for autox, and on track I'd tune it down to 375ish whp most likely. A 7163 would be +50 to 75 whp in both cases. The 7670 would again be +50 to 75 whp. That's more than enough power if you get the reliability, weight, handling, and aero right.

The amount of heat production above 500 whp is pretty high, and the wear and tear on mechanical parts above that is equally high. I've tracked cars from 90 whp to 470 whp and honestly I will always go for the ones with the broadest power bands. A 7670 should be able to make plenty of power, while giving a broader band than the 8474 which prevents extra shifting (chances to screw up). I honestly question people who think they'll quickly grow out of big power setups. Make the car reliable, quick out of corners, fast enough on the straights to not be embarrassing, and spend the money saved from not breaking engines all the time on handling and light weight stuff, which makes the car faster again.

There's a reason I track a 2,375 lbs (with me in it) civic and 125 whp but regularly pass "track" cars with big power.
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Old 11-04-2020, 04:29 PM   #8
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Quote:
Originally Posted by subydude View Post
There's a reason I track a 2,375 lbs (with me in it) civic and 125 whp but regularly pass "track" cars with big power.
I have a lot of room to grow as a driver, car setup, etc etc so I agree on the 7670 probably being enough for me for some time...

I don't know if I can really have a chance of ever being competitive in Street Mod Gridlife no matter what with the way i've built and kind of want to keep the car (still a family sunday driver). So it may be more reasonable to stay at a level that won't kill a motor a season.
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Old 11-04-2020, 04:58 PM   #9
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Quote:
Originally Posted by Barge View Post
I have a lot of room to grow as a driver, car setup, etc etc so I agree on the 7670 probably being enough for me for some time...

I don't know if I can really have a chance of ever being competitive in Street Mod Gridlife no matter what with the way i've built and kind of want to keep the car (still a family sunday driver). So it may be more reasonable to stay at a level that won't kill a motor a season.
That bolded bit right there says don't even run a 7670 with custom setup. Until you're willing to commit to a track build you will run compromise after compromise and having a ton of money tied up in a power adder you can't properly use that's pushing around a bunch of extra weight because you want the idea of driving it with other people in it on the weekends is just not the way to go. I've seen guys say they want a track and autox combo build and will tell them the design for each is very different if you want to be competitive. There are cars that can package both, but they definitely aren't Subarus

That being said, running a 400 whp setup (7163 in the stock location would do it) to start with on a not stupid expensive setup is an acceptable step to see how you like it. That way some of the costs are easily recouped if you back out, and 400 whp is way more than enough to go fast.

When you commit to it and are willing to take the car off the road and make true competition decisions, then more power would be useful. Again, this is all IMO. After all, I still track a civic and mostly do autox
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Old 11-04-2020, 05:06 PM   #10
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Originally Posted by subydude View Post
That bolded bit right there says don't even run a 7670 with custom setup. Until you're willing to commit to a track build you will run compromise after compromise...

When you commit to it and are willing to take the car off the road and make true competition decisions, then more power would be useful. Again, this is all IMO. After all, I still track a civic and mostly do autox
My Sunday driver limits may be a bit beyond some... but I'm well into the compromise game. That's why i'm fulling willing to accept that I won't really be a top3/10 whatever... but I want to have fun, compete, and at least show well.



With E85 and the 20g turbo I have no there's really no point into even changing turbos until I bump to something 500+ range.
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Old 11-30-2020, 10:26 PM   #11
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Quote:
Originally Posted by subydude View Post
A 7670 should be able to make plenty of power, while giving a broader band than the 8474 which prevents extra shifting (chances to screw up). I honestly question people who think they'll quickly grow out of big power setups. Make the car reliable, quick out of corners, fast enough on the straights to not be embarrassing, and spend the money saved from not breaking engines all the time on handling and light weight stuff, which makes the car faster again.
Largely agreed! I do however question if a 7670 would actually have a broader powerband than an 8474. I think 'easier' or lazier to drive powerband might be more fitting. From what I've seen, the two are capable of comparably long powerbands. One is just bigger and spools later...and requires a much bigger budget to keep operating.

Quote:
Originally Posted by subydude View Post
There's a reason I track a 2,375 lbs (with me in it) civic and 125 whp but regularly pass "track" cars with big power.
Calm your pants there, Colin Chapman!!


Quote:
Originally Posted by Barge View Post
I have a lot of room to grow as a driver, car setup, etc etc so I agree on the 7670 probably being enough for me for some time...

I don't know if I can really have a chance of ever being competitive in Street Mod Gridlife.
SM at Gridlife is a pretty wild class. I've been looking to build my coupe for it. Hoping my shoulder recovers in time for me to get some wrench time.

If you're in it for fun factor, I think a 7163 or 7670 would be the ticket. If you were building an engine with all of the revs but lower boost (wink wink), the 8474 might be a stupid broad torque curve. BW's have pretty broad compressor maps for lower PRs.
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Old 12-01-2020, 12:46 PM   #12
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Originally Posted by Homemade WRX View Post

If you're in it for fun factor, I think a 7163 or 7670 would be the ticket. If you were building an engine with all of the revs but lower boost (wink wink), the 8474 might be a stupid broad torque curve. BW's have pretty broad compressor maps for lower PRs.
I think that's what is making things harder on me. I've got some stages to my planned "motor program" (makes it sound more professional if I call it a motor program haha) that has enough variation in displacement and especially RPM that it makes it hard to have 1 turbo really fit it all.

I'm now heavily leaning towards a 7163 and just making sure something like an 8474 will fit physically. That way I can have an enjoyable powerband now with the motor spec that I have and as I grow to a higher RPM creation (which is the direction I wanna go) I can at least try to ensure my fabrication work doesn't need to be scrapped.
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