Megasquirt build question: Wideband O2 or no?

Low budget build mk2 VW Golf with a 2.0 16V 9A.

I am putting this together with a Megasquirt 2 Ver3.0, running HAL effect off stock distributor/Bosch module.

I am currently putting the exhaust/header together and it's off the car. I have a newish 3-wire Bosch O2 sensor. Will I regret not putting a wideband on the car after I try to get this running?

Budget is tapped out, but it's the optimal time to install since the header is sitting on the ground.

....so, wait till next month's paycheck? or just put it together and try to get it running?

Sorry for rookie question, but first attempt at MegaSquirt anything, and trying to balance a car project on pinched pennies, with plenty of other things left to buy.

I couldn't imagine trying to get a car running on a standalone ecu without a wideband.

Last wbo2 sensor I bought was only $40 and it has like long ass pigtail to boot.

Ranger50 wrote: Last wbo2 sensor I bought was only $40 and it has like long ass pigtail to boot.

The sensor isn't the expensive or hard part. It won't do you much good without a controller in OP's case.

You could build this into the MS case for ~$40 + sensor: http://www.14point7.com/products/slc-oem

Or just pickup this for ~$75 + Sensor: http://www.14point7.com/products/spartan-lambda-controller-2

bluej wrote: You could build this into the MS case for ~$40 + sensor: http://www.14point7.com/products/slc-oem Or just pickup this for ~$75 + Sensor: http://www.14point7.com/products/spartan-lambda-controller-2

Interesting.

Thanks for the links.

I've always been intrigued by those, but i have to wonder about support. In modern versions of TunerStudio, you can literally just select which wideband you're using and it'll have the values already there, assuming you don't have a ground offset problem.

The MTX-L can be had for about $150, same with the AEM UEGO. MTX-L recently upgraded to the Bosch LSU 4.9 as well.

I couldn't imagine tuning without a wideband, it seems like it would be way more frustrating than just doing it right in the first place.

Could you junkyard from one of the VWs that had a factory Bosch 4.2 wideband? Then just pair it with that $40 Sigma board, which looks awesome.

You should definitely tune with a wideband, there's no question about that. The question is if you want to run a target AFR table or run open-loop from a stored table...which basically comes down to whether you think your O2 sensor or your fuel system are more likely to give trouble.

I wouldn't do anything without a wideband.

Just had a shop do an install without one, when we started trying to tune it.. well it was a bit challenging and the customer is paying for it via my time.

You can tune without a wideband - as long as you're just looking for stoich. And it's definitely possible to do some tuning without one even if you're aiming for something else. We haven't always had them! Heck, "narrowbands" respond quicker so they're often preferable for idle behavior. We actually run one of each in our setups.

But it's best to have one.

Swank Force One wrote: I've always been intrigued by those, but i have to wonder about support. In modern versions of TunerStudio, you can literally just select which wideband you're using and it'll have the values already there, assuming you don't have a ground offset problem. The MTX-L can be had for about $150, same with the AEM UEGO. MTX-L recently upgraded to the Bosch LSU 4.9 as well.

The values usually mimic another widebands settings in Tunerstudio or you can calibrate using the two baseline starting voltages the 14.7 controller sends. I'm not completely savvy in the process because we are using a really ooooold version of that system that doesn't have as much current info out there. As far as support, the owner of the company responded personally to email questions pretty quickly.

MrJoshua wrote:

Swank Force One wrote: I've always been intrigued by those, but i have to wonder about support. In modern versions of TunerStudio, you can literally just select which wideband you're using and it'll have the values already there, assuming you don't have a ground offset problem. The MTX-L can be had for about $150, same with the AEM UEGO. MTX-L recently upgraded to the Bosch LSU 4.9 as well.

The values usually mimic another widebands settings in Tunerstudio or you can calibrate using the two baseline starting voltages the 14.7 controller sends. I'm not completely savvy in the process because we are using a really ooooold version of that system that doesn't have as much current info out there. As far as support, the owner of the company responded personally to email questions pretty quickly.

Sorry, i worded that pretty funny. I'm not calling that company out, they've been around for awhile. That's the dude that did the JAW (Just Another Wideband).

I meant support more on the TunerStudio side of things.

If you're quick you can tune to stoich everywhere with a narrowband and a separate air/fuel ratio table fully populated to 14.7, and then once the VE table is done, you can turn off closed loop operation (in whole or in part) alter the air/fuel ratio target table to reflect where you want the engine to run.

I say "if you're quick" because you really don't want to run at high load and stoich for very long.

Widebands are not that expensive, practically speaking.

In reply to Swank Force One:

Yep, the one we have is a JAW. As long as you set it correctly in the settings you shouldn't have to worry about it again (well, unless you treat it like total crap for 8 years like we have then it may get cold natured). I don't know how much the MSExtra forum guys have adopted them. That would be where I would look to see if it would have easy MS community support.

Keith Tanner wrote: You can tune without a wideband - as long as you're just looking for stoich. And it's definitely possible to do some tuning without one even if you're aiming for something else. We haven't always had them! Heck, "narrowbands" respond quicker so they're often preferable for idle behavior. We actually run one of each in our setups. But it's best to have one.

This guy has a point, but I definitely wouldn't go without one at this point.

If the header is on the floor now you should at least weld the bung in place. Check Jeg's or Summit for bung and plug kits there like $12. This way when you do have the $$ you can add it quickly. (make sure to use anti-seize on the plug threads)

If you want a bung and plug kit, stop by your local exhaust shop. They weld them in all day long. Faster than waiting for shipping from an internet store. The plug can be a dead O2 or even a bolt.

44Dwarf wrote: If the header is on the floor now you should at least weld the bung in place. Check Jeg's or Summit for bung and plug kits there like $12. This way when you do have the $$ you can add it quickly. (make sure to use anti-seize on the plug threads)

Well to verify yes there is already a bung. I just happend to have a standard O2 laying around, but I don't own a wideband/controller (yet).

Solid input all around. Thanks everyone.

Tuning without a wideband is like shaving with out shaving cream.

You can do it, but is it worth the pain?

dusting this back off as I now need to actually order something, and I have a few extra car bucks to spend.

I'm looking at the glowshift version of controller and gauge myself.

But watching to see what's recommended.

Wideband. Period.

Can a MS3 handle a wideband by itself? Or does it still need a separate controller? Seems like the elephant in the room...

It will need a separate controller. However, it can be configured to work with any controller's output, and there are configs for 99.9% of the widebands out there.

I'd recommend the LC-2, via from DIYAutotune. They have a very competitive price and it's a decent unit with a cheap replacement sensor.

Although IMO the LC-1 is better, but it's not made anymore.