The limits of boost?
Thread Starter
Driver
Joined: Apr 2014
Posts: 67
Likes: 25
From: Western Australia
The limits of boost?
Hi guys, long time lurker -- New member.
A supercharger kit is in my future and I know what's currently out there for these cars. I also know the current pitfalls for these cars - high compression and no tuning.
So this leads me to my question. I haven't seen anyone running more than 7-8psi on these cars. The reason for this seems to be the high compression ratio, yet the Subaru BRZ/Scion 86 twins suffer from the same issue (actually slightly higher compression than our cars). A small search on the BRZ/86 forums and plenty of them seem to run far higher psi on stock internals and pump. The only logical reason for the lack of detonation seems to be the direct injection allowing for more boost on higher static compression. Is it possible that with adequate fueling our engines are capable of taking a lot more boost without engine knock..?
The same discussions of why only low amounts of boost could be run were had on the twins forum in the early days of their release.
A supercharger kit is in my future and I know what's currently out there for these cars. I also know the current pitfalls for these cars - high compression and no tuning.
So this leads me to my question. I haven't seen anyone running more than 7-8psi on these cars. The reason for this seems to be the high compression ratio, yet the Subaru BRZ/Scion 86 twins suffer from the same issue (actually slightly higher compression than our cars). A small search on the BRZ/86 forums and plenty of them seem to run far higher psi on stock internals and pump. The only logical reason for the lack of detonation seems to be the direct injection allowing for more boost on higher static compression. Is it possible that with adequate fueling our engines are capable of taking a lot more boost without engine knock..?
The same discussions of why only low amounts of boost could be run were had on the twins forum in the early days of their release.
I'd run 10psi on the 2gr if fueling was adequate....but it's not. You'll see 90%+ IDC right around 8psi. A simple remedy is upgrading the stock fuel pump AND adding a 1000cc 7th injector to supply extra fueling at 8psi like the good ole days of simplistic fueling. 
How will the stock ecu react to additional boost? From my datalogs it would lead me to believe just fine provided the extra fuel is only introduced by psi and not wot or similar.
Here's a quick FYI thread I started regarding FP upgrades.
https://www.clublexus.com/forums/per...e-options.html
Saturn sky users gave me great ideas for boost activated add-on injectors if you google search.
How will the stock ecu react to additional boost? From my datalogs it would lead me to believe just fine provided the extra fuel is only introduced by psi and not wot or similar.
Here's a quick FYI thread I started regarding FP upgrades.
https://www.clublexus.com/forums/per...e-options.html
Saturn sky users gave me great ideas for boost activated add-on injectors if you google search.
Last edited by mikellucci; Apr 27, 2014 at 09:32 AM.
I'm not really sure as there's a lot to consider. By changing out any of the injectors you then need a way to tune fueling. The stock ecu does too good of a job with low boost for me to want to interfere with that. By adding a 7th injector you eliminate the need for tuning being that it only activates over 7.5psi.
^^DI, I highly doubt; the port injectors are probably the ones that you'd wanna look at upgrading since they are activated more often when pushing it. BUT, will the ecu be able to control said larger injectors? Nobody knows.
Thread Starter
Driver
Joined: Apr 2014
Posts: 67
Likes: 25
From: Western Australia
Arma use additional injectors in their supercharger kit as far as I'm aware? Come across a couple of people here in Aus with the kit and they certainly aren't running meth water injection to stop them from leaning out.
I'm not really sure as there's a lot to consider. By changing out any of the injectors you then need a way to tune fueling. The stock ecu does too good of a job with low boost for me to want to interfere with that. By adding a 7th injector you eliminate the need for tuning being that it only activates over 7.5psi.
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Thread Starter
Driver
Joined: Apr 2014
Posts: 67
Likes: 25
From: Western Australia
But yes otherwise a fuel pump and more injectors would seem the most logical way solve the issue.
Would you go higher than 10psi (assuming fueling it wasn't an issue) on meth/water? On e85 and high octane race fuel you can run more boost generally in a higher compression environment so with meth/water injection the same thing should be possible eh?
Would you go higher than 10psi (assuming fueling it wasn't an issue) on meth/water? On e85 and high octane race fuel you can run more boost generally in a higher compression environment so with meth/water injection the same thing should be possible eh?
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