Another S/C'd member worried about his AFR - Toyota Yaris Forums

largeorangefont · 03-27-2009, 04:38 AM

Quote:

Originally Posted by LtNoogie

Thanks to CTScott, I found the OEM fuel pressure regulator. It is not in a place that is easily replaced by an aftermarket unit. Since the fuel system's pressure is now maxed out at the 44.1 to 49.7 psi put out by the OEM regulator, using another regulator after this unit to get higher pressure is impossible.

Dyno guy now admits that replacement of the fuel pump (like Garm's turbo install) or replacement of the stock injectors is probably in order if the goal is to get more fuel to the engine during boost.

Calculating the proper injectors size, using the many online injector calculators, is a little bit daunting but I'll use them all until I can understand the concept and get consistent results.

I'd rather understand the science behind the proper selection of injectors rather than just shotgunning any device in and hoping that they do the job adequately.

If that is truly the problem, you could try a boost-a-pump. You need a scan gauge or tool that can tell you injector duty cycle to know for sure if you need anything.

You guys will not be able to solve this by just swapping out parts. You will solve one problem and create 5 more with bigger injectors.

LtNoogie · 03-27-2009, 10:42 AM

Quote:

Originally Posted by largeorangefont

If that is truly the problem, you could try a boost-a-pump. You need a scan gauge or tool that can tell you injector duty cycle to know for sure if you need anything.

You guys will not be able to solve this by just swapping out parts. You will solve one problem and create 5 more with bigger injectors.

What is a boost-a-pump? Can you post a link to a comparable product online? I have not seen injector duty cycle as available for display on the ScanGauge. I am guessing that some instrumentation would have to be connected to the injector wires to measure duty cycle? This intrument would have to be sturdy enough to measure during WOT?

TOUGEghost · 03-28-2009, 12:27 AM

Quote:

Originally Posted by LtNoogie

What is a boost-a-pump? Can you post a link to a comparable product online?

Here's the link:

http://store.summitracing.com/partde...5&autoview=sku

It increases voltage to the fuel pump as boost increases. Seems like it could be a good solution for moderate boost levels.

LtNoogie · 03-28-2009, 12:46 AM

Quote:

Originally Posted by TOUGEghost

Here's the link:

http://store.summitracing.com/partde...5&autoview=sku

It increases voltage to the fuel pump as boost increases. Seems like it could be a good solution for moderate boost levels.

Thanks, I had seen that earlier. My thought is that a properly working fuel pressure regulator will hold the current pressure unless it fails. My water pressure regulator at the inlet to my home maintains a constant 80psi across a wide band of street pressure.

Any mechanical engineers out there?

dallas · 03-28-2009, 01:48 AM

Ive seen the Boost-a-pump used on a buddys Mustang and it works well, if you need to squeeze a bit more out of the fuel pump. If Richard Holdners Intake /exhaust combo made more hp than the supercharger it must be using more fuel to acheive this. I don't think it's the fuel delivery, but maybe the management of the delivery thats causing a lean condition. I wish you pioneers luck to figure this out.

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03-28-2009, 01:48 AM	#5
dallas Drives: Yaris Hatch /Landrover D2 Join Date: Jun 2007 Location: Canada Posts: 242	Ive seen the Boost-a-pump used on a buddys Mustang and it works well, if you need to squeeze a bit more out of the fuel pump. If Richard Holdners Intake /exhaust combo made more hp than the supercharger it must be using more fuel to acheive this. I don't think it's the fuel delivery, but maybe the management of the delivery thats causing a lean condition. I wish you pioneers luck to figure this out.