safe boost on level on V-Power?

[FD_Ken]

Hi guys,

I've heard some mixed opinions on how much boost you can SAFELY run on 98 octane pump fuel in a 13B turbo.
Ben at Rotary Motorsports wont go over 14psi, others are saying 16psi is fine.
My car is spewing out black sooty smoke when on full boost. Seems very rich???
opinions?

[Stretch]

Just for the record, Are we talking internally stock fd 13b rew twin turbo?
Stretch

[Shifta]

Just to add to this, pump fuel in Australia is measured in RON. What is usually described as octane is AKI in the United States.
93 octane (AKI) = 98 RON

But yes, A mod list will help the tuning gurus on this forum answer your questions.
Upgraded fuel system, turbo setup etc would play a big part in how much boost a tuner would feel safe about having your car run.

[Black Talon]

I'll add my 2 cents, and you can make of it what you will.

There is NO SPECIFIC SAFE BOOST LEVEL as you would call it for ANY grade of fuel, regardless of the type of engine.

It's all about the tune. There is no reason why you couldn't run 30psi on 91 octane pump fuel. It's all about the tune and a few specific parts of your setup. If your tuner says it's not safe to run more than Xpsi, then your tuner simply isn't good enough at tuning to do it.

That's all there is to it.


As for the whole 14psi I keep hearing about... well that's more to do with the stock MAP sensor than anything else. It will only measure 2BAR absolute. That means roughly 14.5psi over average atmospheric pressure (the ambient air is at approx 1BAR, plus 1BAR = 2BAR). This is the only real limiting factor on the stock setup.

If you go to the effort and replace the MAP sensor with a 3BAR one, then there's no reason at all why you can't run 29psi.

You can get an Apexi 3BAR one that plugs in to the factory harness, but it's not cheap. Alternatively you can get a GM one from Banzai Racing for less than half the price, including an adapter harness and shipping.

Both of these would require a little calibration in your ECU, but any competent tuner should be able to do that.

[Earthvillager]

Boost, fuel octane, fuel maps, fuel pump, ignition, map sensor, rotor seals and engine build and condition, exhaust (free flowing or not), tuning...are all interrelated ..... Get something wrong at higher boost =new engine

[ROTATE]

Hi guys,

I've heard some mixed opinions on how much boost you can SAFELY run on 98 octane pump fuel in a 13B turbo.
Ben at Rotary Motorsports wont go over 14psi, others are saying 16psi is fine.
My car is spewing out black sooty smoke when on full boost. Seems very rich???
opinions?

Rich.
Check your spark plugs

[FD_Ken]

Just for the record, Are we talking internally stock fd 13b rew twin turbo?
Stretch

No far from.

-Large extend port
-Haltech PS1000 ECU
-Garret gt3788
-Rochester 1000cc injectors
-Bosch 044 fuel pump
-Custom fuel rails and fuel lines
-Magna flow fuel reg

all balanced and rotors clearanced.

I bought the car this way and as usual the guy I bought it off wasn't completely honest.
I've been told 14psi with this turbo is very low??

[FD_Ken]

I'll add my 2 cents, and you can make of it what you will.

There is NO SPECIFIC SAFE BOOST LEVEL as you would call it for ANY grade of fuel, regardless of the type of engine.

It's all about the tune. There is no reason why you couldn't run 30psi on 91 octane pump fuel. It's all about the tune and a few specific parts of your setup. If your tuner says it's not safe to run more than Xpsi, then your tuner simply isn't good enough at tuning to do it.

That's all there is to it.


As for the whole 14psi I keep hearing about... well that's more to do with the stock MAP sensor than anything else. It will only measure 2BAR absolute. That means roughly 14.5psi over average atmospheric pressure (the ambient air is at approx 1BAR, plus 1BAR = 2BAR). This is the only real limiting factor on the stock setup.

If you go to the effort and replace the MAP sensor with a 3BAR one, then there's no reason at all why you can't run 29psi.

You can get an Apexi 3BAR one that plugs in to the factory harness, but it's not cheap. Alternatively you can get a GM one from Banzai Racing for less than half the price, including an adapter harness and shipping.

Both of these would require a little calibration in your ECU, but any competent tuner should be able to do that.



you sure know your shit mate, btw I checked my thermostat after you mentioned it in a previous post and turns out it was the wrong size and was also not working properly.
Cheers!

[Stretch]

Nice mods, what sort of power is it currently making can I ask?
Im going similar mods, sadly no porting but same turbo so very interested. If you have a healthy motor and a big turbo/upgraded fuel system then yes 14psi does seem conservative. Got any dyno sheets, AFR info or vids of it running? :)
Stretch

[FD_Ken]

Nice mods, what sort of power is it currently making can I ask?
Im going similar mods, sadly no porting but same turbo so very interested. If you have a healthy motor and a big turbo/upgraded fuel system then yes 14psi does seem conservative. Got any dyno sheets, AFR info or vids of it running? :)
Stretch

It`s a long story Stretch but I''l try and keep it short..

Bought the car and took it straight to Ben at R/motorsport.
At 18psi was making around the 430HP mark atw but Ben said the tune was a mess.
Re-tuned at 14psi and is now making around 350HP.
I have the dyno sheet somewhere so I'll try and dig it out.

I had some issues with it getting hot which I think I have sorted.

-No understray
-Wrong size thermostat
-Plazmaman IC

Still have the IC but need to take the car to the track again to give it a real test.

Also recently discovered I have a small water seal leak sooooo looks like I'll be pulling the engine out soon....

I think the guy I bought it off may have over heated it at some stage as it was only recently built. The muppet was also using the wrong pre-mix oil.

[EATV8S]

Hi guys,

I've heard some mixed opinions on how much boost you can SAFELY run on 98 octane pump fuel in a 13B turbo.
Ben at Rotary Motorsports wont go over 14psi, others are saying 16psi is fine.
My car is spewing out black sooty smoke when on full boost. Seems very rich???
opinions?

I have tuned rotary turbos with a substantial amount more boost than the above on 98 pump fuel with no issues at all. All it means is you can not add as much advanced ignition timing as you can with higher octane race fuels. High boost is fine on any fuel readily available provided safe knock levels are not exceeded.

As for the black smoke on boost, I would be confident to say that those load cells are tuned too rich and that will be causing rich AFR's