paddlenbike

iTrader: (1)

I keep hearing that installation of the TRD supercharger on a 3.4L results in lean conditions in the upper RPM range. Assuming you were to install the S/C exactly as recommended by TRD, what kind of A/F ratios are we talking about here?

ravencr

It really depends on the truck, but higher than 14.7:1 is definitely going to happen at WOT. How high just depends!

Chris

paddlenbike

iTrader: (1)

That's a time-bomb on a forced induction motor. I can't believe Toyota sells (and warranties!) such a lethal package.

rwmorrisonjr

What does that ratio mean? I installed the S/C about a month ago and am running at 5,000' above sea level, so I know that does effect the A/F ratio, but I'm not sure by how much.

ravencr

Sad but true, but I've also heard they are working on a complete system, but who knows!

Chris

ravencr

You're probably fine on your AFR's at that elevation.

Chris

paddlenbike

iTrader: (1)

It's a ratio of the amount of air in the combustion chamber to the amount of fuel. At idle and light loads, the ECU attempts to keep the A/F ratios around 14.7:1 to reduce emissions and fuel consumption. At higher engine loads more fuel is added to increase power output and, contrary to what you might think, cool the combustion charge. If the stock fuel system isn't capable of supporting enough fuel at higher RPMs, the mixture becomes lean and cylinder temperatures rise. Boost raises these temperatures even further and you risk melting aluminum pistons with lean conditions. You also risk detonation which can damage engine internals or lead to blown headgaskets.

its2slo

you heard right. trd now admits there is a problem, but they are still jack asses. they are now selling a 7th injector for a rediculous $1300.

edit:i notice you are a turbo guy and see why this would alarm you!! so many people dont understand detonation.

ravencr

Where is it being installed?

Chris

its2slo

i dont think anyone knows yet, but since they want to call it an intercooler i would assume pre-compressor. like a really crappy trd substitute for alcohol injection(or water).

ravencr

That would be interesting, because they claim that injectiing any fluid before the impellers is a bad thing for the S/C. I wonder where we could find out more information on it?

Chris

its2slo

heres where i got my info chris, have fun bud!!

http://forums.delphiforums.com/n/mb/...95116.1&maxT=2

paddlenbike

iTrader: (1)

I thought I'd mention that even at almost twice the stock boost, my A/F ratios are off the chart at well below 9:1. Supras run pig-rich from the factory so-as to protect the engine. I could mod it the cheap way and install a fuel cut defenser (FCD) and continue to up the boost, but then I'd be where you guys are at, running the fuel system on the ragged edge. So I will be ordering a Walbro fuel pump ($95), Lexus V8 AFM ($100 used), new 550cc injectors ($375) and AFPR so I can safely turn up the boost. I have an Air Fuel Controller (AFC) I bought off Ebay for $61 that will allow me to tune it to the mid-11:1 range for safety. If I were in your guys' boat, I would buy larger injectors and a cheap AFC like I got and richen the mixture in the upper RPM ranges. Much cheaper than what TRD is likely to come up with and you'll fix the lean problem in the upper RPM range. But I admit that I have no hands-on experience with the 3.4 and am only speculating what the limiting factors may be...

its2slo

sounds right on to me, plus maybe water injection for some more power.....