Another S/C'd member worried about his AFR

[LtNoogie]

I can't wait to see what a properly tuned Blitz'd Yaris can put out. I know we've been admonished not to put larger injectors on this car but hear me out on this theory.

What if the current fuel system with the Blitz piggyback fuel controller cannot pump enough fuel into the cylinders during WOT, leading to a lean condition. The ECU detects pre-ignition and has to retard timing to protect the engine, and as a consequence robs us of the maximum power the S/C can put out.

If I put slightly, not hugely, larger injectors in the car, it may run less lean during WOT and the ignition retard is less, giving more power. During idle or light throttle, the ECU detects a rich condition from the O2 sensor and is able to dial back the fuel to maintain proper AFR. Remember, I said slightly larger injectors, not fire hoses. If the increase in fuel is within the ECU's cabability to control, that could just work.

Anyhow, that's the theory I want to present to my dyno guy if I have him tune the car.

[CASTREX]

Garm's car has been running with TC injectors on the OEM ECU right?

And iirc he didn't had any idle or part throttle problems... just a lean condition at WOT... but that was @ 180 whp

I say your theory is worth a shot if you can find some injectors for cheap.

Look for injectors from a Celica GTs, corolla/ matrix XRS. I think those are a little smaller than the TC's.

You can look into the 6 gen celica forums for those..

[RagnaCaT]

Originally Posted by LtNoogie

I can't wait to see what a properly tuned Blitz'd Yaris can put out. I know we've been admonished not to put larger injectors on this car but hear me out on this theory.

What if the current fuel system with the Blitz piggyback fuel controller cannot pump enough fuel into the cylinders during WOT, leading to a lean condition. The ECU detects pre-ignition and has to retard timing to protect the engine, and as a consequence robs us of the maximum power the S/C can put out.

If I put slightly, not hugely, larger injectors in the car, it may run less lean during WOT and the ignition retard is less, giving more power. During idle or light throttle, the ECU detects a rich condition from the O2 sensor and is able to dial back the fuel to maintain proper AFR. Remember, I said slightly larger injectors, not fire hoses. If the increase in fuel is within the ECU's cabability to control, that could just work.

Anyhow, that's the theory I want to present to my dyno guy if I have him tune the car.

This is the smartest post, try OEM injectors from a 1.8 like corolla or XD could help you out??? i would go for it I swapped camry 2.0 3S-FE injectors on a corolla 1.6 4A-FE modded and got almost 2 hp at WOT and that was an N/A setup you are FI

[whooppee777]

at a local auto-x event this weekend i had a nice chat with a turbo charged xa and he told me that he was running the blitz supercharger with nitrous before going turbo (he's blown his engine 5 times)

he said he had a lot of issues with the belt slipping and asked him about a/f ratios and he said that the blitz kit really has the stock injectors pushed to its limits.

now this guy also works at the shop in northern virginia which has a high reutation so this isnt some averge joe, hes a tech at this shop that knows what hes talking about.

sounds like bigger injectors r the way to go and a stronger fuel pump would also help. an adjustable fuel pump is not an option on our cars. see cali's thread on his turbo build for the explanation

[bearda]

Originally Posted by whooppee777

now this guy also works at the shop in northern virginia which has a high reutation so this isnt some averge joe, hes a tech at this shop that knows what hes talking about.

Which shop is he running out of? Ptuning?