[Clap135]

I also spoke with shiv about another issue as I have decent experience with DI cars.
You can develop a fuel system that supports 40000whp. However ultimatly you are limited by the injection times each injector has to fire the fuel. In that small window, you can only squirt so much fuel, and if you try to extend that window then you will run into overlap issues and piss out fuel out the valves giving the o2 sensors false rich conditions

[Clap135]

Originally Posted by indy99gpgt

I would imagine you can run more boost without meth. More fuel to mix with more air. Safer and more consistent AFR's at higher power levels.

that has nothing to do with hardware, that has to do with the type of tune you are running.

[mithiral67]

Originally Posted by 335iPSI

Stock turbo's are very efficient at lower RPM... lets do some 22psi from 2k-5k tapering to 17 at redline, could be 500wtq down low all day! Reminds me of my SRT4 days... like 400tq and 280whp lol.

A half a dozen half shafts just shatter with ur post.

[335iPSI]

Originally Posted by mithiral67

A half a dozen half shafts just shatter with ur post.

Eh... I've got 4 driven half-shafts (xi !) and an AT... bring it on!

[ianthegreat]

Great research shiv

[indy99gpgt]

Originally Posted by Clap135

that has nothing to do with hardware, that has to do with the type of tune you are running.

How is that? If you turn up the boost dont you need the hardware to support it? Ive always considered supporting mods to be the most important. You can make 22psi all day but if you dont have the fuel/injector to push the fuel, you are going to run lean. Most of the afr graphs i have seen of the high hp cars on here seem to start getting in the high 12's for afr. I always considered 11.5:1 to be the perfect afr for a FI car. I could be wrong but that is how ive always gone about modifying cars.

[pentaxis]

Originally Posted by indy99gpgt

How is that? If you turn up the boost dont you need the hardware to support it? Ive always considered supporting mods to be the most important. You can make 22psi all day but if you dont have the fuel/injector to push the fuel, you are going to run lean. Most of the afr graphs i have seen of the high hp cars on here seem to start getting in the high 12's for afr. I always considered 11.5:1 to be the perfect afr for a FI car. I could be wrong but that is how ive always gone about modifying cars.

DI equipped cars can run leaner AFRs.

[Clap135]

Originally Posted by indy99gpgt

How is that? If you turn up the boost dont you need the hardware to support it? Ive always considered supporting mods to be the most important. You can make 22psi all day but if you dont have the fuel/injector to push the fuel, you are going to run lean. Most of the afr graphs i have seen of the high hp cars on here seem to start getting in the high 12's for afr. I always considered 11.5:1 to be the perfect afr for a FI car. I could be wrong but that is how ive always gone about modifying cars.

its not if they high 12s, its when they hit 12s. Some tune are limited in fuel control.

[indy99gpgt]

its not if they high 12s, its when they hit 12s. Some tune are limited in fuel control.

Ahh, I see. Thanks for the explanation.

[OpenFlash]

Anyone who is targeting 11.5:1 AFR on this engine must have stock in oil companies. Or just not know how to tune it.

Shiv

[Clap135]

Originally Posted by shiv@vishnu

Anyone who is targeting 11.5:1 AFR on this engine must have stock in oil companies. Or just not know how to tune it.

Shiv

yea cause when you are floored, getting 1.7mpg is much better then 1.2mpg lol

[OpenFlash]

Originally Posted by Clap135

yea cause when you are floored, getting 1.7mpg is much better then 1.2mpg lol

The point I was making is that it is undesirable to target an unnecessarily rich AFR for the sake of saying "look how much richer I am running". With these engines, over-fueling beyond a point has no discernible effect on knock resistance or cylinder temps. It just results in power loss and reduced fuel economy. Also, the injection window on this DI engine is quite narrow so extending the injection time of the injectors will never get to the point where valve opening is going to be an issue. It's also worth mentioning that there has been no evidence of a discrete injector on-time limitation in this application. The limit, until now, has been induced by other components in the fuel system.

That said, any further tuning discussion is best left for another thread. This one is about fuel system capacity.

Shiv

[Jake@MOTIV]

All my v5 logs show afrs from 11.0-11.5 throughout the power band

[Clap135]

Originally Posted by shiv@vishnu

The point I was making is that it is undesirable to target an unnecessarily rich AFR for the sake of saying "look how much richer I am running". With these engines, over-fueling beyond a point has no discernible effect on knock resistance or cylinder temps. It just results in power loss and reduced fuel economy. That said, any further tuning discussion is best left for another thread. This one is about fuel system capacity.

Shiv

Well I already commented on the fuel system capacity, but you chose to respond to someone else comment about running 11.5 a/f ratios.

[Clap135]

Originally Posted by FlyLow335i

All my v5 logs show afrs from 11.0-11.5 throughout the power band

mine showed the complete opposite, I was running as high as 18s at some points of the power band. Those af reading, imo, are not very accurate.

[OpenFlash]

Originally Posted by FlyLow335i

All my v5 logs show afrs from 11.0-11.5 throughout the power band

Up top at high RPM, it's normal to run that rich. But if you are seeing those AFRs in in the meat of the powerband, something is wrong. Either you are injecting too much meth. Or your meth mix has too much water.

Shiv

[Clap135]

Originally Posted by shiv@vishnu

Up top at high RPM, it's normal to run that rich. But if you are seeing those AFRs in in the meat of the powerband, something is wrong. Either you are injecting too much meth. Or your meth mix has too much water.

Shiv

But it is a closed system, it will target the same af ratio.

I sprayed meth with the COBB, m10 nozzle, 100 percent meth, 14psi falling to 13, af didn't change. I also used the same set up with windshield washer fluid which is mainly water with some meth mixed in, af didn't change.

[Jake@MOTIV]

Irregardless of how much meth I run - its a closed loop system. You are swaying the widebands to run the AFR you want. Im using a 100ml/min and 225ml/min nozzle from snow. At my pump pressure its about 600ml/min so smaller than an M10. My tank is filled with about a 75-80%meth/20-25%water mix

[OpenFlash]

Originally Posted by Clap135

But it is a closed system, it will target the same af ratio.

I sprayed meth with the COBB, m10 nozzle, 100 percent meth, 14psi falling to 13, af didn't change. I also used the same set up with windshield washer fluid which is mainly water with some meth mixed in, af didn't change.

Chris,
Yes, it's a closed loop system. But if you are injecting too much meth/water, it will exceed the limits of the system's authority range and overshoot the AFR target. 1 single M10 nozzle isn't enough to do this. These days, some high hp guys are using dual M14s.

Shiv

[OpenFlash]

Originally Posted by FlyLow335i

Irregardless of how much meth I run - its a closed loop system. You are swaying the widebands to run the AFR you want. Im using a 100ml/min and 225ml/min nozzle from snow. At my pump pressure its about 600ml/min so smaller than an M10

Your AFR is in line with what i would expect to see at that high RPM, during a short 2 second low gear WOT pull. Not enough time for the DME to hit the AFR target. Try again in a more appropriate gear and start the run at a lower engine speed and you will probably see something different.

And please, let's keep on topic.

Shiv

[indy99gpgt]

Originally Posted by shiv@vishnu

Anyone who is targeting 11.5:1 AFR on this engine must have stock in oil companies. Or just not know how to tune it.

Shiv

On EFI cars, 11.5-11.7 was always the sweet spot if you were a forced induction engine. You could go leaner if the engine was knock free. Ive never moded or tuned a DI engine so that is just what I assumed.

Sorry for making it off topic, im just trying to learn.

[Brey335i]

So Shiv, to keep this on topic, I will extend you the same question that I asked before lol. Will us non-meth, non-RB turbo guys see a power/drivability benefit or will it only benefit high hp crazy people?