Correct FMU ratio with different injectors

[markwt]

First would like to thank you in advance for any advice/help. Turboing is def a huge learning curve, too much info out both good and bad.
I have an 05 busa that I am installing a EVO III T3 g16 turbo, going to run between 6-8 psi. I installed a .08" spacer plate and plan to run stock pistons, rods, and injectors. I purchaced a Walbro 255 fuel pump and had purchaced a Magna Fuel regulator with boost 1:1 ratio. The more I research it sounds like the 1:1 ratio is not the way to go with low psi boost and stock injectors. I figure I will be around the 225-250 hp range. Some have said to go with a 6:1 or an 8:1 ratio FMU. Please let me know advice on what ratio FMU I should use and as well if I am safe using the stock pistons, rods, and injectors. Thanks again

 

[VIPER]

from all my reading on turbos etc you are safe with the stock internals. Many have boosted more then you are on stock internals. you might want to ad what ear of busa as this does matter for the advice you want.

 

[Boosted Cycle Perf]

With a base spacer your good for 300hp on stock internals.

As far as fmu 8:1. Go with the fmu from Rcc, it will do exactly what you need, and is a very reliable unit.

 

[markwt]

Thank for the advice. I was just told by MPS that if I kept stock injectors and ECU program that I would need to go with an 8:1 fmu. If I got a 650cc injector and they flashed my ecu with the map for them, I would need to use the magna fuel 1: regulator. Does this sound right? I don't want to doubt what he is telling me, just trying to figure out the best setup. If I do not have to spend a ton more buying new injectors and flash my ecu for minimal performance then I won't. Sounds like I will need to flash mu ECU either way, but wouldn't buy $350 injectors for a few hp

 

[Boosted Cycle Perf]

Yeah that right. Either way you go, I would Reflash the ecu anyways. Ecu is far superior then any aftermarket piggy back system you can buy.

 

[markwt]

So sounds like I already have the 1:1 regulator and I have to get my ecu flashed anyway, I may as well get the bigger injectors incase...I am sure I will next winter...I decide to go with more boost. Sounds like stock injectors are pretty maxed out at around 8 psi boost. You agree Murdered

 

[Boosted Cycle Perf]

It's not so much they're maxed out as at 8psi the duty cycle is still in a safe margin. It's more the fueling pressure you need to use in order to achieve your desiered afr. That's basically what your doing with an fmu is pushing a ton of pressure through your injectors to maximize they're output/ over clock them. Really anything over 110psi and the injectors won't even close.

However, on a gen 1 bike, if you don't run a secondary set of injectors, you can't run big primaries with a 1:1 because the ecu doesn't do boost referenced fueling. You would have to add a power commander with a hub, and run a 3 bar sensor, and use the boost compensate map on it.

 

[markwt]

I appriciate yourt time and help, thank you

 

[Boosted Cycle Perf]

Not a problem, happy boosting.