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Afr's Rb25Det Neo

Bugzs15

By Bugzs15,
in Engines & Forced Induction

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Bugzs15 Contributor

Bugzs15

Posted
Posted

I got my results recently and wanted to confirm if these AFR's are ok.

Car is stock apart from some Jap ECU (Impul) and Cat back exhaust.

Made 150kw and 250 nm

my afr's are as follows:

13:1 @ 2,800rpm @ 6psi

12.5:1 @ 3,500 rpm @ 6psi

12:1 @ 3,750 rpm @ 6 psi

11.5:1 @4,750 @ 6.5psi

11:1 @ 5,100 rpm @ 7psi

10.5:1 @ 6,250 rpm @ 6 psi

150kw @ 5,750rpm

250nm @ 5,250rpm

I wish to put in a bleed valve (GFB) and raise the boost to a constant 7-8psi, with the above AFR's do you think I still have a safety margin.

Car was not detonating on the dyno, i just want to make sure I wont cause issues if I put in an MBC, especially if my boost comes on earlier where i am the leanest with regard to AFR's.

I do have an aftermarket Jap ecu (Impul) which is for 100 octane i think. So by running 98 ron i was cautious and had it Dynoed after turning the boost down from 12psi (set in Japan) to 6-7psi.

Any advice appreciated guys.

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https://www.sau.com.au/forums/topic/436003-afrs-rb25det-neo/
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Ben C34 Grand Master

Ben C34

Posted
Posted

It is going quite rich which is expected on an untuned ecu.

You cant just aim for a specific afr though, you have to give the engine what it wants, which varies between engines.

You are also forgetting timing. You cant guess what thats doing.

Why didnt yiu just crank the boost whule it was on the dyno?

Bugzs15 Contributor

Bugzs15

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  • Author
Posted (edited)

It is going quite rich which is expected on an untuned ecu.

You cant just aim for a specific afr though, you have to give the engine what it wants, which varies between engines.

You are also forgetting timing. You cant guess what thats doing.

Why didnt yiu just crank the boost whule it was on the dyno?

It was dynoed to check for timing issues as well and seemed to hold up ok. definitely going to tune it in the future. Just need funds as I just imported the car and also had major service done. Wanted to steady the boost at 7psi but wasn't sure if it's safe to do so as it leans a bit in lower rev range and GFB advertise for their MBC to bring boost on earlier so need to know how safe it is for me to do that. Didn't have a boost controller when it was dynoed so couldn't experiment at the time. Edited by Bugzs15

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