Never heard of silicone you could use on exhaust you sure its not jb weld? I think it would burn up... And crans im pretty sure the injectors are always squirting fuel prolly for a short period of time but I'm like 95% sure they don't stop prolly on newer vehicles to cut down emissions but I don't see the ecu cutting off fuel

 

thought wrong...650° silicone for making gaskets...



the whole point behind the injector statement was to clarify the reason as to why i was installing larger injectors and MAP sensor on my NA engine, and explaining that any size injector will work on a properly programmed ECU. How they work is irrelevant. Sorry, just trying to stay on the subject .

 

not sure on the reset, there may be a pin-hole logic reset button or something on the back, i don't remember. I don't have the manual for mine, i borrowed the manual from my buddy, for installation, and gave it back.

there's stuff you can buy, it's like a high temp epoxy specifically for patching exhaust leaks, that RTV might still burn off, i used it on all my laser cut steel turbo gaskets, and it stinks when it burns, lol. The reason i asked was just that your WOT reading seems leaner than a good tune, unless you have fuel delivery issues, and the ECU is pulling timing so i'll clarify:

Were you reving in neutral, or doing an actual pull? the reason is because the load on the engine plays a role in the fuel map, where a neutral rev, has no load, so AFR would be close to target idle AFR. the more load there is on the engine, the richer it should be...like 13.4-13.9 would be a good high rpm AFR for a 2nd or 3rd gear pull. then again the way an automatic uses engine power is much different than a manual...


The ECU absolutely cuts fuel when you let off...i know this partly because most, if not all modern fuel injected cars do this, and my wideband shows me that it's happening...below a certain speed, it will resume fuelling.

It wouldn't make sense to spray less fuel, this would create a lean condition. that and it wouldn't be to reduce emissions, because not fuelling would reduce emissions, and not fuelling would save fuel, so it's a win-win system...these are computers, they deal with fuel and iginition timing in the micro-seconds...6000rpm is 100rps that's a lot of combustion cycles in one second, and fuel delivery and ignition are tiny fractions of each revolution.

 

Neutral rev ... I don't have the wire routed through to the outside of the car yet so I have to remain standing.

 

ok, then that makes sense that it was well into the 14's with the throttle wide open

 

Hi guys. Someone asked me to read and comment on this.

First, the manifold that I've been making suits the T3/T04B with an internal wastegate. I have one left that "someone in this thread" has dibs on. I do have a second one partially made so I could probably finish it if someone wanted to buy it off me.

Second, the size of the injectors doesn't really matter as I just program the ECU to run whatever size you have. Even if there is a tiny exhaust leak in the system it really only affects the reading at idle. 14.2 is way too lean at WOT - assuming you're driving. Normal ralliarts will run 10.6:1 at high RPMs and WOT. Possibly the MAF sensor is going bad, there is a massive intake leak or some other reason for this.

I like the idea of moving over to the larger injectors while still NA given that an unknown injector can be tweaked until it runs perfectly without the added complication of adding boost too. Different turbos flow different amounts so that's complicated too.

-Michael

 

I'm glad we got that all cleared up , thanks hack

Out of curiousity how much for the manifold?

 

hack, he got that reading with a zero load neutral rev.

 

Lmao wow.... No I didn't think wrong that is what I thought you used but I would never use it for exhaust.. I used that stuff to seal my transmission works great

 

You got confused that's what I meant that the only reason I would see a car cut the fuel is for emissions

 

Yeah that stuff will melt off, the exhaust will get hotter than 650f especially once turbo.

 

oh sorry, you said "they don't stop prolly on newer vehicles"...i thought you meant the injectors don't stop spraying to reduce emissions, which didn't make sense to me...my point is that when you let off, the ECU does in fact cut fuel

 

I used what the muffler shop recommended. It's not melting off, and I'm not turbo. When I go turbo the down pipe and flex pipe will be changed, and this sealant will obviously not be considered with temps approaching/exceeding 900°F.

 

Touchy touchy

 

Again, "you thought wrong."