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Boosting high compression engine on pump gas safety

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Hey guys,

I have a fully built Honda H22A engine with Mahle 11.5:1 pistons and Eagle H beam rods. My original plan was to keep it Naturally Aspirated, but I would now like to turbocharge it. I am very new to turbocharging so my question is, is it safe to turbocharge a higher compression engine like this on 95 octane pump fuel? If so, what sort of boost numbers could I expect to run safely on a turbo such as a precision 5831?

Kind Regards,


95 RON ain't much RON. Since you will have a built motor, the best approach is to spend time on a dyno to look at the trade off between boost, timing, and knock to make power. What ECU are you using?

Hey. Thanks for your reply.

I am using a Hondata S300, but it doesn't have knock control as far as I am aware. Also if I remember correctly, I believe our 95 pump gas is equivalent to 93 in the USA. Someone may be able to correct me on that. I don't have E85 readily available in my area so that isn't really an option either. The best I can get in my area is 98 octane with 10% ethanol blend.

I just want to know if it can be done relatively safely before I go ahead and start gathering all the parts.

I should also add that I am really only looking to run maybe around 8 to 10psi, Shooting for around 350whp. Or more if possible. The car is also not my daily driver.

Kind Regards,


95 RON is about 91 octane in the US, which is the lower premium fuel.

I think a big thing you need to keep in mind is having a good wastegate and manifold to keep the boost under control. If you have a poorly flowing wastegate, you will overboost when the weather is cold, and then you will either hit a boost limit (fuel cut set in the ECU or whatever) or you could damage something.

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