|
![]() |
|
|
![]() |
|
Thread Tools | Display Modes |
![]() |
#1 |
Scooby Newbie
Member#: 99268
Join Date: Oct 2005
Location: Clayton, NC
Vehicle:2018 Sti Type RA Blue |
![]() Ok before you roast, I did a search and read the recommended threads. I'm still ill informed.
So, I'm getting stage 2, SF intake/box, air/oil separator, and a protune on an ' 18 type RA. I know on Cobb's site they don't recommend this setup, but the tuner said there is a lot of misinformation out there regarding this setup and says i'll be fine/safe. This is a very reputable shop that does a wide variety of cars and is a COBB certified gold protuner. (Prolly just means they paid for the title lmao) So, since I'm sure there is a lot more people that have experience with this setup now vs the old threads I found...I'd love to hear input on people that have actually run this setup or tuners that have tuned it. Assuming no other mods, should this be ok to run with a protune? Is Cobb's non-recommendation simply because it is risky with an OTS tune? I appreciate any input. Thank you.
* Registered users of the site do not see these ads.
|
![]() |
![]() |
![]() |
#2 |
Scooby Newbie
Member#: 450712
Join Date: Jul 2016
Location: Indiana
Vehicle:04 STi WRB |
![]() If the OTS map notes don't list the mods that will work with it then it is not recommended to be used and there is a risk of a lean condition.
Now if you're getting a protune, then the tuner will be able to take care of any mods done to the car and you shouldn't need to worry. You're on the right track my listening to your tuner and what he recommends. |
![]() |
![]() |
![]() |
#3 |
Scooby Newbie
Member#: 186068
Join Date: Aug 2008
Chapter/Region:
South East
Location: NC
Vehicle:2019 STi DGM |
![]() Cobb doesn’t do it for their OTS map because they run rich putting IDCs higher with just a DP. So when you add the intake the stock injectors will be running at max if it was an OTS tune from Cobb. With a protune he will tune it to be efficient and safe so you won’t have to worry.
|
![]() |
![]() |
![]() |
#4 |
Scooby Specialist
Member#: 111641
Join Date: Apr 2006
Chapter/Region:
MWSOC
Location: St. Louis, MO
Vehicle:2020 CWP STi RIP - 06' WRX w/ 6spd |
![]() Skip the intake IMO, the airbox is better and you can use the money for something else. There is no better intake than the stock airbox until you are pushing enough power to actually need a new one, which you aren't at stage 2. Even truer for the 18RA and 19-20 STI's which have a revised airbox and scoop setup.
I know they sound cool but IAT's will suffer and MAF scaling won't be as good as OEM. |
![]() |
![]() |
![]() |
#5 |
Scooby Newbie
Member#: 99268
Join Date: Oct 2005
Location: Clayton, NC
Vehicle:2018 Sti Type RA Blue |
![]() Thank you guys so much. This is pretty much exactly what i was looking for. Thanks for the help.
|
![]() |
![]() |
![]() |
#6 | |
Scooby Specialist
Member#: 181298
Join Date: May 2008
Chapter/Region:
MAIC
Location: MAIC
Vehicle:2019 KUV 21 Crystal White |
![]() Quote:
Mods shouldn't matter much since the tune will be tailored for the car. The next concern should be injectors, fuel pump or Fuel Pressure Regulator. OTS Map has Required parts list... |
|
![]() |
![]() |
![]() |
#7 |
Scooby Newbie
Member#: 99268
Join Date: Oct 2005
Location: Clayton, NC
Vehicle:2018 Sti Type RA Blue |
![]() Protune. Will stay on this setup for a while and see how i like it. Next step will be fuel system with E85 conversion, but that will probably be next tax season lol.
|
![]() |
![]() |
![]() |
#8 |
Scooby Newbie
Member#: 510655
Join Date: Jan 2020
|
![]() Running it right now, except with an upgraded pump and regulator pushing higher fuel pressure. Without a new pump and increased pressure it's dangerous. The stock injectors at stock pressure will get overrun but up the psi and tune for it, you're gtg. There's more to get adjusted as well in the tune. If you want more info lmk but I'm not here to steal anyone's business.
|
![]() |
![]() |
![]() |
#9 |
Scooby Newbie
Member#: 510655
Join Date: Jan 2020
|
![]() Parts list schmartslist... do the fpr and pump, skip the injectors... prove me wrong besides what cobb has to say.
|
![]() |
![]() |
![]() |
#10 |
Scooby Specialist
Member#: 181298
Join Date: May 2008
Chapter/Region:
MAIC
Location: MAIC
Vehicle:2019 KUV 21 Crystal White |
![]() |
![]() |
![]() |
![]() |
#11 |
Scooby Specialist
Member#: 111641
Join Date: Apr 2006
Chapter/Region:
MWSOC
Location: St. Louis, MO
Vehicle:2020 CWP STi RIP - 06' WRX w/ 6spd |
![]() Why do the newer STI's suddenly (supposedly) need more fuel than we ever did on the GD's? Stage 2 cars never needed injectors before, why now? They aren't making anymore power than they ever did 15 years ago.
|
![]() |
![]() |
![]() |
#12 | |
Scooby Guru
Member#: 50586
Join Date: Dec 2003
Chapter/Region:
RMIC
Location: Colorado Springs
Vehicle:2020 STI Crystal White Pearl |
![]() Quote:
![]() |
|
![]() |
![]() |
![]() |
#13 | ||
Scooby Specialist
Member#: 447898
Join Date: May 2016
Chapter/Region:
BAIC
Location: W Sac, CA
Vehicle:2016 WRX (traded) 2019 STI CWP |
![]() Supposedly, the newer models make more power even when modded. This was initially discovered when the 15s were released.. and then another power bump was noticed with the 18 RA/19+ STIs.
One theory was that the hotside of the turbo was larger. Perrin initially speculated this and BrenTuning also noted a significant difference on the dyno when comparing a 2014 vs 2015 STI. Some members of the community then confirmed this by measuring their VF48s. https://www.perrin.com/blog/post/per...obb-accessport Quote:
Quote:
Last edited by WRXnick16; 02-20-2020 at 01:15 PM. |
||
![]() |
![]() |
![]() |
#14 | |
Scooby Guru
Member#: 50586
Join Date: Dec 2003
Chapter/Region:
RMIC
Location: Colorado Springs
Vehicle:2020 STI Crystal White Pearl |
![]() Quote:
|
|
![]() |
![]() |
![]() |
#15 |
Scooby Specialist
Member#: 447898
Join Date: May 2016
Chapter/Region:
BAIC
Location: W Sac, CA
Vehicle:2016 WRX (traded) 2019 STI CWP |
![]() Of course Subaru never announced this and the VF48 part # remained the same. So who knows if it was an intentional design change or the result of an IHI casting/manufacturing change.
|
![]() |
![]() |
![]() |
#16 |
Scooby Newbie
Member#: 490876
Join Date: Aug 2018
Chapter/Region:
NWIC
Vehicle:2016 STI Ice Silver Metallic |
![]() Not to hijack, just curious... How much of a performance difference would there be on a 2016 STi by adding the Cobb SF intake (w/correctly adjusted tune) to a Stage 2 setup consisting of Cobb TBE exhaust, everything else stock.
I do understand IAT's will suffer, MAF scaling won't be as good as OEM and the tune will need to taper because IDCs being pushed. Does anyone have a dyno graph comparing the two? |
![]() |
![]() |
![]() |
#17 | |
Scooby Newbie
Member#: 416298
Join Date: Mar 2015
Location: Houston, TX
Vehicle:2015 STI Limited Galaxy/Lapis Blue |
![]() Quote:
|
|
![]() |
![]() |
![]() |
#18 | |
Scooby Specialist
Member#: 447898
Join Date: May 2016
Chapter/Region:
BAIC
Location: W Sac, CA
Vehicle:2016 WRX (traded) 2019 STI CWP |
![]() Quote:
Here are Cobb's dynos for stage 2 & stage 3 (with upgrade fuel system). There's probably a ~10-15 hp gain (+/-) after 5k rpm. Figure less than that with the tune scaled back for stock injectors. Stage 2: ![]() Stage 3: ![]() I personally recommend going with an ELH before an intake. But most people just follow Cobb's stages or are just after the sound that an intake and the OEM UELH offer. Last edited by WRXnick16; 02-20-2020 at 04:51 PM. |
|
![]() |
![]() |
![]() |
#19 |
Scooby Newbie
Member#: 490876
Join Date: Aug 2018
Chapter/Region:
NWIC
Vehicle:2016 STI Ice Silver Metallic |
![]() @WRXnick16. Thanks for the insight. I appreciate it.
|
![]() |
![]() |
![]() |
#20 | |
Scooby Newbie
Member#: 510655
Join Date: Jan 2020
|
![]() Quote:
![]() |
|
![]() |
![]() |
![]() |
#21 |
Scooby Newbie
Member#: 499183
Join Date: Mar 2019
Chapter/Region:
Tri-State
Location: NY
Vehicle:2019 STI |
![]() The highest I'd want to see my IDC is 90% tops. Calibrators aim for 80%, that's what it's at stock.
Cobb Stage 2 (catted) puts you at the limit which is why Stage 3 package includes the fuel system upgrade, and they're only adding what... their SF intake and a turbo inlet. I'd do the same going catless, at least pump and injectors. |
![]() |
![]() |
![]() |
#22 |
Scooby Newbie
Member#: 303722
Join Date: Dec 2011
Location: Florida
Vehicle:2018 WRX STi type RA WRB |
![]() From what my tuner told me on my RA is that just going stage 2 without injectors or any fuel modification will max out the stock injectors especially on a cold climate day they tend to go 100% very quickly. He recommended at least a fuel pump and highly suggested injectors to be safe. a set of 1050x arent too expensive for piece of mind and will make over 400whp on pump so that is what i am going to do for the time being
|
![]() |
![]() |
![]() |
#23 | |
Scooby Specialist
Member#: 447898
Join Date: May 2016
Chapter/Region:
BAIC
Location: W Sac, CA
Vehicle:2016 WRX (traded) 2019 STI CWP |
![]() Quote:
Of course, there's the debate on how Subaru's IDCs are calculated (based on IPW & RPM) and many tuners have gone well over 100% IDC (see end of post). IDC is a calculated value (with a margin of error), not a raw counter produced by the ECU. Obviously going over 100% wouldn't be possible if the IDC values were accurate, real-time values. I've seen tuners go as high as 120% IDC, but of course those tunes run a higher risk of running lean under the right conditions. In that case, you need to pay close attention to the AFRs, especially in colder weather and at high load in higher gears. Or if you spend extended periods of time at high RPMs (track car). Cobb tests in cool climates with high atmospheric pressure (low altitude) where the air density is high (demanding more fuel) to check their IDCs. At stage 2+, their IDCs were at 107% with their AFR and they considered that unsafe for an OTS tune in that environment. Of course they err on the side of caution which is why they're known for their long-term reliability. Their tunes also run on the richer side for added safety (using more fuel) which further increases their higher IDCs. A protune will typically run leaner resulting in more power and lower IDCs. Cobb also wouldn't mind convincing you to spend more money on their fuel upgrade package ![]() Subaru's reported 100% IDC != absolute 100% IDC (static injector operation). For example, 126% IDC: ![]() |
|
![]() |
![]() |
![]() |
#24 | |
Scooby Specialist
Member#: 181298
Join Date: May 2008
Chapter/Region:
MAIC
Location: MAIC
Vehicle:2019 KUV 21 Crystal White |
![]() Quote:
|
|
![]() |
![]() |
![]() |
#25 | |
Scooby Specialist
Member#: 447898
Join Date: May 2016
Chapter/Region:
BAIC
Location: W Sac, CA
Vehicle:2016 WRX (traded) 2019 STI CWP |
![]() IDCs start to become a limitation at the top of 4th gear on Stage 2+ setups with the stock injectors.
While this is a "limitation".. how much time does an average street car spend at WOT at ~90-100+ mph? It just so happens that 4th gear is the most commonly used for dyno tuning and the higher IDCs are observed. Tuners will of course err on the side of caution. They don't want any responsibility (blame) in you potentially running lean, detonating, and experiencing a catastrophic engine failure. They also have to assume the worst of your driving habits (ie maniacally doing extended WOT pulls in excess of 100 mph at sea level in below freezing temperatures when air is the densest despite your their warnings about IDCs with the stock injectors). I'm not opposed to upgrading the injectors at Stage 2+, but it isn't really necessary for a daily driver unless it's spending weekends doing extended track sessions. If you have the money to burn and it helps you sleep better at night.. then by all means go for it. Or just reach out to a few experienced tuners and ask their opinion. Most will be willing to tune your setup on the stock injectors. They'll just scale power back a bit in the higher gears for safety. For example: Quote:
|
|
![]() |
![]() |
![]() |
Thread Tools | |
Display Modes | |
|
|