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3SGTE Gen 4 safe Boost on Pump Gas

162 Views 5 Replies 4 Participants Last post by  benckj
Hey everyone, my car is Gen 4 swapped and is stock atm with the exception of:

3 inch intake
3 inch downpipe and exhaust
CT20B turbo.
Front Mount Intercooler

However, its currently at wastegate (8psi). From the persons ive spoken to with caldinas they hit about 13psi. I was considering raising mine a bit but the thing im worried about is fuel. Here in Trinidad where I live the best fuel at the pump we have is 95RON.

Was wondering what would be safe boost levels using this fuel? Anyone had experiences with it?

Thanks in advance.
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I believe the Gen 4 was designed for 95 Octane. 95 RON is about 91 octane.

I run 17PSI on 93 Octane on my daily and I've put about 50k miles on the swap already (CT15b). Every now and then under WOT I can feel the knock sensor pulling some timing. Recently some gas stations in my area have started selling 94 Octane. After filling up there was a noticeable reduction in detonation (less timing being pulled).

On 91 Octane your limit will be lower. I'd suggest increasing boost slowly until you start getting detonation, dial it back a hair, and that will be your limit. Honestly 13PSI is probably close to that limit already.

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Might be worth looking into water injection. Its a great way to raise octane, lower intake temps and protect engine from possible detonation. I put a basic system on my car when high octane fuel became unavailable following earthquakes.

As mentioned, 13psi would be max and even this can cause issues in the right circumstances (high ambient temps, low octane fuel, poor ignition components, etc). You didn't mention a boost controller or boost gauge to measure pressure. These can also have an adverse effect on accurate set-points. Simply having a large spike is enough to gernade engine!
I put this gen4 in in 2018

Intake/Intercooler/Downpipe/Exhaust/Boost Controller 17PSI

91 Octane MN fuel, occasionally 92 from Costco or 93 from BP
Currently don't have a boost gauge or controller. I usually monitor boost through Torque Pro, i'm on the stock auto ecu as well.

What would you guys recommend for an EBC? I was looking at the GFB Gforce 3, but wasn't sure if it would've made sense due to my fuel restriction. I've heard of stock engines grenading at as little as 15psi here.

What sort of water injection units would you all recommend as i'm on the stock ecu.
I’m not up to date with EBC’s. I installed an HKS EVC-s because it had a small controller with digital readout for boost gauge. It’s not an easy EBC to program or control.

For WI a simple kit from Coolmist, Devils Own or otters would suffice. Only need a pressure switch to turn 200psi pump when set boost reached. Can even use your window washer tank to supply. Kits get expensive with progressive or failsafe systems.

Hope this helps.
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