How Much Boost on Built Motor?

[rideyamaha287]

i wanna know if you guys think it is safe to run 5 psi on a built motor i disconnected the portfueler until i can get it tuned in. but in the mean while i have the following fuel mods walbro, aeromotive regulator. obx fuel rail and i ran the return line my self. i dont want to hurt my motor i dont have a wideband i just have the worthless narrow band.. what do you guys think

 

[Fotowntalon]

i wanna know if you guys think it is safe to run 5 psi on a built motor i disconnected the portfueler until i can get it tuned in. but in the mean while i have the following fuel mods walbro, aeromotive regulator. obx fuel rail and i ran the return line my self. i dont want to hurt my motor i dont have a wideband i just have the worthless narrow band.. what do you guys think

general consensus says its safe to run around 8-10 psi on a stock motor, i'd imagine you'd be fine

 

[rideyamaha287]

general consensus says its safe to run around 8-10 psi on a stock motor, i'd imagine you'd be fine

yeah thats what i thought 2 but just makin sure. thanks

 

[tec_41]

Psh crank it up...I've run 7 on a stock motor for about 5k now. Yours will handle it

 

[rideyamaha287]

Psh crank it up...I've run 7 on a stock motor for about 5k now. Yours will handle it

do you have a fmu or is it the stock fuel system..? i wanna turn it up but im afraid to hurt my motor...but i think i will be fine. up until about 10 what do you think...

 

[Rob10_99]

What kind of built... that's the real question.
Built engines can take 30psi on a daily, that doesn't mean your rings will last more than 10k miles but still.

 

[tec_41]

do you have a fmu or is it the stock fuel system..? i wanna turn it up but im afraid to hurt my motor...but i think i will be fine. up until about 10 what do you think...

Well you need to upgrade your fuel system regardless- A FMU is the bare minimum. Otherwise SFMU, or some kind of engine management is next.

Stock injectors limit you to about 8psi max, so that's another issue.

I run a 12:1 FMU, Walbro 255, and stock injectors for now.

 

[rideyamaha287]

[QUOTERob10_99;152033861]What kind of built... that's the real question.
Built engines can take 30psi on a daily, that doesn't mean your rings will last more than 10k miles but still.[/QUOTE]

i just wanna know its gonna be safe to run about 5-8 psi on just a walbro,obx f.rail,i made my own return line and i have a aeromotive regulator thats about it and the portfueler but i need to tune it in the maps are all mest up...

 

[Locke]

With the PortFueler properly tuned, and the engine in otherwise healthy condition, it'll handle 8psi just fine.

 

[rstare]

With your portfueler disconnected, as you said it is currently, you shouldn't run any boost.
As someone else mentioned, you'd need an 12:1 FMU, otherwise you're going to be extremely lean.

 

[rideyamaha287]

With your portfueler disconnected, as you said it is currently, you shouldn't run any boost.
As someone else mentioned, you'd need an 12:1 FMU, otherwise you're going to be extremely lean.

yeah i need my portfueler to be tuned in. i took my car to a performance shop and they couldnt fix the bog and then i un plugged the vac line to the portfueler and it stopped bogging so those guys are idiots they should have street tuned the portfueler dont you think.

 

[rideyamaha287]

I fixed the bogging. all i did is email hahn and got the stage 5 software and i programed the software and i took it for a spin and no bog. those guys have great customer service for the most part.But i had one more question, how much boost can i run until my ecu starts pulling timing? i have dis II but i have no clue how to mess with timing.

 

[Locke]

The factory ECU won't pull time unless it senses knock. When knock will occur depends on far to many variables, not that you'd ever want it to knock.

Knock = bad.

 

[rideyamaha287]

The factory ECU won't pull time unless it senses knock. When knock will occur depends on far to many variables, not that you'd ever want it to knock.

Knock = bad.

so would i be able 2 run 15psi with the portfueler non tuned for now. i just feel like i should be running alot i have a built bottom and top end with stock cams...

 

[xceler8]

wow! ok, so you can basically run as much boost as you want given you have propper fuel and spark so your not knocking as Locke put it.
If your running the 1:1 with return line and no portfueler, I wouldn't run any boost. you need to raise your fuel pressure higher than 1 psi per pound of boost. basically fuel injectors will dump more fuel than their rated amount if the static pressure behind them is higher. So with a 12:1 regulator, it will raise your fuel pressure higher based on the boost it sees. therefore, more boost more pressure more juice through your injectors. If your only going up 1 psi of fuel per psi of boost, your not nearly getting enough fuel and will definetly knock and cause daage on your nicely built block. yes, you can destroy your forged pistons! I've done it at 16psi with a bad fuel setup. Don't do it, just wait till it's all gravy with your fuel setup.
By the way, if you don't have a wideband..get one! Anyone running boost should have one if they don't I don't feel sorry for them when they blow their motors.

 

[Locke]

Don't run it unless it is tuned.