I was just wondering, has anyone actually seen a difference from one side of the engine vs the other when running dual widebands on a turbcharged DE? I am planning out my turbo system and dual widebands is something I am considering, but I am wondering if its really worth it for a low boost setup. Does one side of the engine run inherently leaner than the other?

Let's say I did have dual widebands…and a UTEC. Does the UTEC even have the capability to adjust injector pulsewidth individually for each cylinder? If not, then I assume you would tune using the leaner of the two readings.

Thanks!

 

The driver side is generally accepted as being the leaner of the 2 banks.

You wont get into bank correction until you buy a Haltech, ViPec, Motec... I dont think that the FCON even does that.

The UTEC definatly does not.

 

where do the dual widebands get mounted anyways? exhaust manifolds? I wonder what the lift of those widebands is...

 

Utec definitely wont be able to do it. I have WB on both bank and the driver side is definitely leaner especially on WOT than the passenger side.

 

athen...do you run haltech?

 

At WOT, under boost, the differences become insignificant on my widebands. A tenth of a point in AFR difference or dead even. At cruise/vacuum there is a very significant difference and that's where having dual widebands really helps to provide smooth engine response, adjusting bank to bank.

So you don't NEED to have it. One wideband is good enough - just keep in mind that the driver's side will be up to 5-10% leaner at low loads / cruise and adjust accordingly if you can. If you can't, you can still adjust low load target AFRs in the low 14 range instead of right at 14.7 and you won't be able to tell the difference in driveability.

 

So it sounds like if I am going with a UTEC, my best option is probably just to use a TXS tuner on the driver's side and call it a day. If the day comes when I want to shoot for big power, I will go with a Haltec and grab a second wideband.

Thanks guys, that's exactly what i needed to know!

 

I have Utec. I dont see much difference when cruising coz the ecu is controlling the A/F to be around 14.7 via 02 feedback. I do have a water/meth so the difference I'm getting could also be the uneven distribution of Meth on each bank. At WOT I can see my driver side .1-.2 leaner than my passenger side.

 

Yes, most tuner here just use the driver side bank for tuning...

 

It does.

-George
GT Motorsports

 

I have the Haltech and dual widebands, and yes, the driver side runs a bit leaner. Most I have ever seen in my datalogs is 5%, and this is at full load/boost. They are actually very good/even at low loads.

I have read many times that if you are using one wideband, put it about a foot down stream from the turbo.

 

my pro efi 48 has 4 widebands dedicted to it...it adjust on each bank based on a/f. I have a 5th wideband on drivers bank but that is just for gauge on my a-pillar....once I get my pro-efi can gauge hooked up it won't be necessary though either....I'll keep it though.

 

I have observed both banks on a number of setups and it seems the largest difference is at idle/cruise, and the widebands approach each other as load/rpm increase.

Thom, do you have any idea how the Proefi fires injectors and how it handles cylinder/bank trims when it only has 4 injector outputs?

 

That explains it. There is a bigger difference at cruise, but it is already corrected for by the stock ECU at the point you're reading it. On the Haltech, you see the final corrected value (which is generally matched up all the time if you have dual widebands), but you can also see the correction factors in real time. So both widebands may read 14.7, but I can see more fuel being added to the driver's side than the passenger's.

 

Dual widebands ftw.

O2 Feedback is god also. I loooveeeee thissss.

I have o2 feedback for lower rpm's. I've been logging the topend/boost on both sensors to see what's up. I was told by Hal you can open up tables for each of the banks to adjust each side. Haven't tried it yet since the car is at the bodyshop. But been logging to see what's up and yes, my topend is a tad bit lopsided.

 

if you get utec get the mpslogger available for the setup. itll log your af when tuning in the correct load scale and rpm. also logs everything else. easement of tuning!@

 

MPS is not bad but UTI > MPS by a mile.

 

^^^hm......gonna have to try it out! gonna try out there uti me also. looks pretty cool ecspecailly with interpolation and smoothening functions.

 

As mentioned the biggest difference is at idle and light cruise. At WOT or heavier loads, the two banks homogenize. Engine idle speeds allow for very specific exhaust pulses, and more turbulence, which helps cause the different readings between banks. Once the engine hits full sound, it's smooths out nicely, as the air is also mixing very nicely in the plenum.

 

Having two widebands in a car is like having two watches, they can eash read a different time, but it doesn't mean that even one of them is exactly right. I have two in my car, and the passenger side originally showed leaner. Why would this be??? So I swapped the sensors (still connected to the same controller) and what do you know....now the drivers side is leaner. These are electronic devices reading current and changes in millivoltes and milliamps, Unless you have a way to "sync" the two, not all widebands are going to read dead equal...especially at light load. Under power, they both even up, no matter which bank they are in. It even does this on with the stock ecu in place with widebands.

The Pro48 can do dual wideband, however on the Z they are paired, so it isn't set up that way. After "synching" the two widebands so they read the same swapping bank to bank, and having my injectors flow tested so I know one isn't flowing more than the others. The variance bank to bank is neglegable.