2003 STI Boost Levels

[Dyzzii]

Hey guys, just had a question about my boost level on my 2003 STI.

 

Car is currently running 23.4PSI peak boost, which just seems a bit high, or is it safe? Past research leads me to believe around 21 is the highest you want to go. It drops down to around 17-18 across the end of the rev range however. Is running the stock JDM VF37 Twin Scroll Turbo.

 

Is tuned on 98 octane running the following mods:

 - Front Mount Intercooler

 - RAGE catless downpipe

 - HKS mid-pipe and tip

 - DW200 In-Tank Fuel Pump

 - Apexi Air Intake Kit

 - Link 3-Port Boost Solenoid

 

Tuner has told me the car sounds fine and is not struggling under boost whatsoever, which is why he set it to this. Just have that 21 figure set in my head of the highest safe number. Should I ask him to lower the boost level. He is a very reputable tuner and has tuned hundreds of these cars, just it has me worried.

 

Any information is appreciated!

[El_Chado]

I'd say if it's been tuned to that boost level it should be fine. I'd be more worried if it had no mods other than a manual boost tap.

[IZichard]

Someone told you to join clubsub from one of the facebook groups right? Welcome to the club.

 

23.4 psi does seem pretty high, however I don't claim to be an expert on this what so ever. If your tuner says that it isn't struggling, afr is fine and intake temps are still reasonable then probably not too much to worry about.

 

Perhaps have a think/talk with your tuner about what you really want from the car. Whether you want to back it down a bit for an under stressed reliable package or whether you want it to be as fast as it can be, like it seems the tuner has set it up.

[KingCole]

I ran around 23 psi peak boost in my V8 STI for about 2 years before I sold it. It was tuned for that so never had any problems

[TNHSTI]

16 minutes ago, KingCole said:

I ran around 23 psi peak boost in my V8 STI for about 2 years before I sold it. It was tuned for that so never had any problems

 

I had the same on my V7 STI, had full catless exhaust and was tuned for 98

 

No Issues either

Edited February 22, 2017 by V7STI1992

[Batbaruman]

welcome bro, that was me on the fb group inviting you here haha  glad you joined up!

 

i have v7 also, it's been tuned at 23 psi target boost so it's safe. if your tuner has the same target boost in mind, all good. if it spikes then that isn't good. before mine was tuned, it would spike whcih could have caused me grief in the long term. i say this because the factory map sensor only capable of reading up to 23psi and after that it doesn't know/can't read higher... so for all you know, it might read 23 but be spiking to 27 (just a random number, for arguments sake).

 

if the tuner has looked at it, he probably has copy of the map  / logs, can you get him to verify what the target boost is and maybe show you the boost curve? i'm no expert but wouldn't have thought stock turbo would hold that boost well, so it's probably going above its boost efficiency with that peak.

 

for example my chart is below, not trying to be one of those dicks who puts up his dyno sheet every post just easiest way to show u example if you dunno what im talking about..

 

 

discuss with tuner, get graphs from him, post back up here if you want 2nd opinion

[boon]

The VF's start to slide out of their map above 21psi but if it's earlier in the RPM, so less flow, it's potentially completely fine.

[Kiwi_Fozze]

It all comes down to the tune. The vf's are small, but they do well considering. I'd imagine you are fine.

 

My old v7 was tuned to 24psi as a daily, but it'd had a lot of tinkering to keep that boost cold on the stock tmic (looooots of water from the sprayers)

[Dyzzii]

On 2/23/2017 at 0:27 AM, IZichard said:

Someone told you to join clubsub from one of the facebook groups right? Welcome to the club.

 

23.4 psi does seem pretty high, however I don't claim to be an expert on this what so ever. If your tuner says that it isn't struggling, afr is fine and intake temps are still reasonable then probably not too much to worry about.

 

Perhaps have a think/talk with your tuner about what you really want from the car. Whether you want to back it down a bit for an under stressed reliable package or whether you want it to be as fast as it can be, like it seems the tuner has set it up.

Yeah they did! Glad I found this place haha. Seems far more useful for information!

On 2/23/2017 at 7:02 PM, Batbaruman said:

welcome bro, that was me on the fb group inviting you here haha  glad you joined up!

 

i have v7 also, it's been tuned at 23 psi target boost so it's safe. if your tuner has the same target boost in mind, all good. if it spikes then that isn't good. before mine was tuned, it would spike whcih could have caused me grief in the long term. i say this because the factory map sensor only capable of reading up to 23psi and after that it doesn't know/can't read higher... so for all you know, it might read 23 but be spiking to 27 (just a random number, for arguments sake).

 

if the tuner has looked at it, he probably has copy of the map  / logs, can you get him to verify what the target boost is and maybe show you the boost curve? i'm no expert but wouldn't have thought stock turbo would hold that boost well, so it's probably going above its boost efficiency with that peak.

 

for example my chart is below, not trying to be one of those dicks who puts up his dyno sheet every post just easiest way to show u example if you dunno what im talking about..

 

 

discuss with tuner, get graphs from him, post back up here if you want 2nd opinion

How the hell are you pulling 867nm of torque!! That's ridiculous! Yeah I have my dyno sheet which shows my boost curve etc. It peaks at 23 and then drops right down to around 16psi at the end of the rev-range which i've been told is normal. Also thanks for the invite to this page! Seems way more reliable than a bloody fb page haha. I may put up a photo of the sheet just to show what it's doing

On 2/27/2017 at 11:39 PM, kwi_fozze said:

It all comes down to the tune. The vf's are small, but they do well considering. I'd imagine you are fine.

 

My old v7 was tuned to 24psi as a daily, but it'd had a lot of tinkering to keep that boost cold on the stock tmic (looooots of water from the sprayers)

Yeah i'm running a front mount to stop that haha. I just need to stop being lazy and get myself another window washer jet so I can relocate it to the front bumper and squirt from both sides.

[Dyzzii]

Heres the boost curve:

 

http://imgur.com/a/ChNBb

 

For some reason it wont let me just upload the photo to the site

[boon]

These motors typically make peak power around 6500rpm and you're only getting 15psi up there. With a FMIC intake temp shouldn't be an issue, wonder why they tuned it to fall off like that? With a 3-port you should in theory be able to hold around 20psi out to the redline, although there's not much point since power falls off like crazy anyway. 

 

That said, our cars were tuned by the same person, and he's tuned a LOT of these cars, so there's no doubt a good reason behind it. I know from my experience that he won't just add boost for boosts sake, if it's running that much boost up there it'll be because it didn't make any more power with more boost.

 

[IZichard]

11 hours ago, Dyzzii said:

Heres the boost curve:

 

http://imgur.com/a/ChNBb

 

For some reason it wont let me just upload the photo to the site

To have the photo displayed you have to paste a direct link to the image file.

"http://i.imgur.com/bx4L1D9.jpg"

Shows up as 

 

You will still have to upload to an image host like imgur as they are not hosted here.

[Kiwi_Fozze]

Your dyno chart isnt scaled correctly. Rpm / torque crossover should be at like 5252 or something around there.

[Andy_Mac]

Only applies to hp/ftlbs though man, ratio's way off with kw/nm

[Dyzzii]

2 hours ago, kwi_fozze said:

Your dyno chart isnt scaled correctly. Rpm / torque crossover should be at like 5252 or something around there.

Are you referencing to batburmans?

[Kiwi_Fozze]

aahh, yes