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Old 08-31-2019, 03:03 PM   #1
cashrolling
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Default Gt35r ej207 tuning HELP

Hi guys. Need ur input on this. Just got my 2013 JDM spec C, it has a full setup to support the gt35r, but internals are stock. Car was tuned for safety. The tuner kept tourque at 352, and hp at 456. He explained to me he tuned it with low torque to keep the rods safe, therefore he played with the boost graph, meaning that he gets 20psi by 4800rpm, and slowly increasing boost to 26psi at 7500rpm, redline 8300( car has meth injection). Ha claims this is the safest way to tune it. I'm hearing different opinions on this. Would it be better have higher boost earlier and taper it down to the redline? Thanks for ur input.....
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Old 08-31-2019, 06:00 PM   #2
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Not if you want that motor to last any amount of time. He's keeping you from breaking a rod!

The way he tuned it is to keep cylinder pressures low (as low as possible with a 35r and 26psi) which will makes your rods much happier.

He is doing it right and keeping your stock bottom end together but with that much power it won't last for long no matter how it's tuned!

Good luck it sounds fun!
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Old 08-31-2019, 07:39 PM   #3
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how does your car feel? a gt35 is going to spool super slow on a 2.0 liter anyways. so yeah if you don't like the tune get someone else to do it. what I know about the ej207, is it doesnt like alot of torque down low anyways. you could probably do more boost but you run the risk of lifting the heads after like after 28ish on stock head studs. so choose yoru poison. if you want to keep your engine running, dont go super crazy and try to push it to see what it will do.
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Old 08-31-2019, 11:31 PM   #4
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The ej207 specC( the one I have) supposed to have different cams and stuff, actually it's not very laggy. By 4000rpm boost starts build and fast, B4 5000 fullboost in 3rd gear, then full power to 8000rpm. It's very nice.
About the tune, as I want it to last as long as possible, I'm going to lower the boost to 24psi, and keep it same way with lower boost at lower rpm and make it increase to redline.
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Old 08-31-2019, 11:43 PM   #5
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Your tune doesn't sound right to me and the EJ207 rods doesn't have a strength issue below 500whp/wtq. Have your tuner redo the tune and make sure there isn't any knock anywhere in the RPM band.
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Old 09-01-2019, 02:02 AM   #6
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Quote:
Originally Posted by Fierysun View Post
Your tune doesn't sound right to me and the EJ207 rods doesn't have a strength issue below 500whp/wtq. Have your tuner redo the tune and make sure there isn't any knock anywhere in the RPM band.
Please , I search but I seems to find differents infos. Help me understand the difference of my engine compare to a regular STI 207. To be more precise my car just imported from Japan, it's a 2013 STI spec C type RA, NBR challenge edition.
Can anyone explain the properties , weaknesses and strength of this engine compare to other similar version? I appreciate the help, don't really have time to spend hours searching the net.
About the tune it's very safe, no knock whatsoever.
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Old 09-01-2019, 12:46 PM   #7
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Quote:
Originally Posted by cashrolling View Post
Please , I search but I seems to find differents infos. Help me understand the difference of my engine compare to a regular STI 207. To be more precise my car just imported from Japan, it's a 2013 STI spec C type RA, NBR challenge edition.
Can anyone explain the properties , weaknesses and strength of this engine compare to other similar version? I appreciate the help, don't really have time to spend hours searching the net.
About the tune it's very safe, no knock whatsoever.
most of the complaints are from the 205 not the 207. the 205 does have rods that are a tad weaker than the 207. 207 rods are the same the usdm sti got.. if you are really worried about strength, get the manley Hbeams and rebuild the block
Quote:
Originally Posted by cashrolling View Post
The ej207 specC( the one I have) supposed to have different cams and stuff, actually it's not very laggy. By 4000rpm boost starts build and fast, B4 5000 fullboost in 3rd gear, then full power to 8000rpm. It's very nice.
About the tune, as I want it to last as long as possible, I'm going to lower the boost to 24psi, and keep it same way with lower boost at lower rpm and make it increase to redline.
you should be fine with 24. if you are happy with the tune you have... dont worry about it. I have a 2.1 with v9 heads and my powerband doenst really come on til 3700 with the avcs working. 4200 without it
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Old 09-02-2019, 09:47 AM   #8
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what gen GT35r are you using and what fuel?
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Old 09-02-2019, 11:44 AM   #9
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Originally Posted by fastnoypi View Post
what gen GT35r are you using and what fuel?
The turbo was bought brand new 6 months ago. Was the best and newest available at that time,most expensive as well. We use 91 octane with water-meth injection
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Old 09-02-2019, 12:55 PM   #10
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judging by the numbers (and meth) in the first post I'm guessing pump gas ?


2013 v10 sti ej207 should have very thick cyl walls , weak link would be pistons , then rods


sounds like his tuner is not a brotuner idiot
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Old 09-02-2019, 06:37 PM   #11
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Quote:
Originally Posted by motorbykemike View Post
judging by the numbers (and meth) in the first post I'm guessing pump gas ?


2013 v10 sti ej207 should have very thick cyl walls , weak link would be pistons , then rods


sounds like his tuner is not a brotuner idiot
gt not gtx remember.. true ti doees have thick walls, but the 2-7 dont really make alot of power down low anyways
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Old 09-02-2019, 11:15 PM   #12
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So, am I safe to keep boost the way it is? As now it spools fast at 21psi by 5000rpm, then slowly increase to 26psi at 7800. Should I lower the top boost to 23 or 24?
Yes. Pump 91 plus meth
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Old 09-03-2019, 07:54 PM   #13
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Quote:
Originally Posted by subaru_gc8 View Post
gt not gtx remember.. true ti doees have thick walls, but the 2-7 dont really make alot of power down low anyways

huh - eng rish pleas e - ?
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Old 09-03-2019, 07:55 PM   #14
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Quote:
Originally Posted by cashrolling View Post
The turbo was bought brand new 6 months ago. Was the best and newest available at that time,most expensive as well. We use 91 octane with water-meth injection


how about a part number for that turbo ?

the box or the tag on the center section has it on it
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Old 09-03-2019, 09:54 PM   #15
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Quote:
Originally Posted by motorbykemike View Post
huh - eng rish pleas e - ?
wow sorry for the spelling errors dang but if you cant figure it out here we go again he said it was a gt not a gtx so the spool will be slow. the 207 does have thick walls but it still a 2.0 and will spool that turbo super slow anyways....better??
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Old 09-04-2019, 12:10 AM   #16
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Quote:
Originally Posted by subaru_gc8 View Post
wow sorry for the spelling errors dang but if you cant figure it out here we go again he said it was a gt not a gtx so the spool will be slow. the 207 does have thick walls but it still a 2.0 and will spool that turbo super slow anyways....better??
Honestly it's not that slow. It's a ar63, and from 4200 it starts spool and fast. Actually I was surprised myself. Then I have progressive power all the way to 8000rpm..
But back to the topic, am I playing with fire here? Should I lower boost to 21psi to be safer? What u think of the way he tuned it, 20psi at full spool slowly increasing to 26psi to redline?
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Old 09-04-2019, 09:37 AM   #17
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really depends on what version of the 35r you are using

it could flow from 54 to 87 lbs/min

that makes a difference because 20lbs of boost on one turbo is not the same as 20lbs on another

it's more about the air mass being moved

part number ?

it's usually the lower set of numbers on the tag on the center section on a garrett
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Old 09-04-2019, 11:49 AM   #18
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Quote:
Originally Posted by motorbykemike View Post
really depends on what version of the 35r you are using

it could flow from 54 to 87 lbs/min

that makes a difference because 20lbs of boost on one turbo is not the same as 20lbs on another

it's more about the air mass being moved

part number ?

it's usually the lower set of numbers on the tag on the center section on a garrett
The turbo number is
706451-5008
Ljm026920
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Old 09-05-2019, 05:04 PM   #19
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Quote:
Originally Posted by cashrolling View Post
Honestly it's not that slow. It's a ar63, and from 4200 it starts spool and fast. Actually I was surprised myself. Then I have progressive power all the way to 8000rpm..
But back to the topic, am I playing with fire here? Should I lower boost to 21psi to be safer? What u think of the way he tuned it, 20psi at full spool slowly increasing to 26psi to redline?
Who applies more boost after full spool (which implies it hasn't reached full spool yet)? When boost should be taping off after that point. Tell you the truth, something is not right with your tuner's logic.

Also, the EJ207 doesn't have rod issues where you need to limit torque. The proper tune would be to give it as much boost as it'll take as early as possible without knock and then taper off when it's no longer making power at that boost/rpm level.

Last edited by Fierysun; 09-05-2019 at 05:11 PM.
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Old 09-05-2019, 11:32 PM   #20
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Originally Posted by Fierysun View Post
Who applies more boost after full spool (which implies it hasn't reached full spool yet)? When boost should be taping off after that point. Tell you the truth, something is not right with your tuner's logic.

Also, the EJ207 doesn't have rod issues where you need to limit torque. The proper tune would be to give it as much boost as it'll take as early as possible without knock and then taper off when it's no longer making power at that boost/rpm level.
Ok. I thought so too. My tuner logic is as follows: limit boost at 20psi initially, (to keep torque low, as he claims that high torque is what kills a stock engine) then slowly increase the boost to 26psi by 7000rpm, that would keep the torque below 360, but power reach 452whp by 7500.
So this is his reasoning. It also news to me, but thinking about it it makes sense, I'm just getting confused. That's why I created this thread, love to hear different inputs.
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Old 09-06-2019, 11:10 AM   #21
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Quote:
Originally Posted by cashrolling View Post
Ok. I thought so too. My tuner logic is as follows: limit boost at 20psi initially, (to keep torque low, as he claims that high torque is what kills a stock engine) then slowly increase the boost to 26psi by 7000rpm, that would keep the torque below 360, but power reach 452whp by 7500.
So this is his reasoning. It also news to me, but thinking about it it makes sense, I'm just getting confused. That's why I created this thread, love to hear different inputs.
Go to a different tuner, his tune strategy will cause more issue than it avoids.
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Old 09-08-2019, 04:28 PM   #22
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Quote:
Originally Posted by cashrolling View Post
Ok. I thought so too. My tuner logic is as follows: limit boost at 20psi initially, (to keep torque low, as he claims that high torque is what kills a stock engine) then slowly increase the boost to 26psi by 7000rpm, that would keep the torque below 360, but power reach 452whp by 7500.
So this is his reasoning. It also news to me, but thinking about it it makes sense, I'm just getting confused. That's why I created this thread, love to hear different inputs.
tuner's logic could be correct but your way could also be correct based on the application. some people taper boost off at WOT to be safe but i understand where he didn't want the full boost early because that's where peak torque is achieved & probably is trying to be conservative to preserve internals & drive train
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Old 09-08-2019, 10:54 PM   #23
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Originally Posted by AR15 View Post
tuner's logic could be correct but your way could also be correct based on the application. some people taper boost off at WOT to be safe but i understand where he didn't want the full boost early because that's where peak torque is achieved & probably is trying to be conservative to preserve internals & drive train
Yes, I called ecutek engineers in England, they agree with my tuner logic, as long as the fueling is good up top . My tuner actually added more meth from 24psi{6000rpm) to keep everything proper. They said that the bigger load is at lower rpm where boost spike, so it's a good thing to keep it lower and raise it with the rpm. That said, car feels amazing, boost never drops, it starts at 23psi by 5000rpm, and get to 26.5psi by 7800. Giving a progressive power feeling all the way to redline.
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Old 09-09-2019, 02:26 PM   #24
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Quote:
Originally Posted by cashrolling View Post
Yes, I called ecutek engineers in England, they agree with my tuner logic, as long as the fueling is good up top . My tuner actually added more meth from 24psi{6000rpm) to keep everything proper. They said that the bigger load is at lower rpm where boost spike, so it's a good thing to keep it lower and raise it with the rpm. That said, car feels amazing, boost never drops, it starts at 23psi by 5000rpm, and get to 26.5psi by 7800. Giving a progressive power feeling all the way to redline.
That tuning method is only valid for motors that have weak rods, which the EJ207 doesn't have. Go to some other tuner that really knows Subaru engines, because the one you went to doesn't.
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Old 09-09-2019, 05:02 PM   #25
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https://www.garrettmotion.com/racing...turbo/gt3582r/

look at the compressor map for yourself. compare boost vs airflow.

Tapering boost controls the speed of the compressor wheel.
Tapering becomes necessary when the compressor is at its limits.
However, consider the vertical line at 55lbs/min, if youre starting at like 20 psi and 30lbs/min at and run out to 55lbs then tapering and maintaining a constant compressor speed will push the turbo into a region that is less efficient than if it climbed up to about 26psi and 55lbs instead.

Efficiency is heat, so at 76% efficiency the air coming out of the turbo is cooler than at 66% efficiency.
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