Ok so I have a wideband, water temp, oil pressure, boost/vacuum gauges already installed.

I was originally going to get an egt and mount it on the crossover y right before the turbo or in the leanest cylinder(which one is leanest in a mustang 302)?

But after some read ait would be usefull aswell. I have a wideband but it doesn't really show me if it's running hot ait or egt just that it's a good afr. But if the afr is good usually egt is good right? So an air gauge would be more usefull?

What's your take? I know I can't keep my eye on all of them but if needed I can watch each one at a time. Example if it's too hot out I can't see if my ait is too hot or not etc.

What do you have in your car? Thanks

 

what fuel ?

 

what temp should you look for when running E85? i just installed some T/C in my exhaust

 

I don't think they are in the same category where you should have one or the other. I don't see many iat gauges, mainly just logs in computers. Egt is more common, but it seems to be on race cars and diesels more often. If its one or the other I would go with Egt just because like I said, most engine management systems log the iat data

 

This is on regular gas, I ditch the e85 idea.

Yea I was recently exposed to ait and it spark my interest as another way to see what your engine is getting.

What's your take on egt placement? In the crossover or right befor the turbo?

I have read that the downpipe placement is useless so it's either on crossover or after one of the cylinder or right before the turbo

 

My knowledge of EGT probe placement stems from the diesel world. In that application, you want the probe as close to your cylinders as possible. By the time the EG makes it to the collector, it has cooled substantially. And I know for a fact that it is potentially a 2-500* drop in the downpipe, compared to in a manifold.

I would choose a location as close to the cylinder as possible.

 

What I am doing and is adding a bung in every header primary. I will then switch an EGT probe into each one of them for a trip down the track, once I know the leanest cylinder I will leave it in that bung. If the engine starts to run strange I can move the EGT around to help trouble shoot. For the AFR I am running one on each side where all 4 primaries come together. All the data from both the EGT and AFRs is data logged to a megasquirt computer allong with the RPM, boost level, etc. This way I can bassically re-play my quarter mile runs and examine the numbers.

Even when I am running a carb, I will use the computer to datalog my runs. To help further I am running a camera and mic so I can have a visual to go allong with the data.

 

Dam that's a good idea except don't know about adding 8 bungs lol
I'll do more research on this And see what cylinder is the leanest for people. If I can't find it I'll just go with #4 or 1

 

You can just look at the plugs . No reason to weld 8 bungs .

AFR readings should be after the turbo .

 

Get the combo working and find out which cylinder is the leanest in YOUR engine... Lots of things can change things like this so treat your combo as an new combo, do not guess things will be the same as similar combos. The bungs are just a place to insert the EGT proble.... Close to the cylinder is a good thing.

 

The reason to run 8 bungs is so that you can do diagnosis or just do a check of every cylinder at any given time... I just run a plug in the probe hole when not in use (remember the never seize on the threads).

I have never heard of the concept of taking the AFR AFTER the turbo, please envighten me on what this info gives you vs an AFR close the the cylinders. Not trying to be rude, just inform me of what the reasoning is...

 

I've always heard that back pressure / pulses will mess with AFR readings . I might be wrong . :noidea:

Heat will also be an issue with 02 sensors .

 

Yep the WB sensor must be after the turbo,

the following is from the innovate LC1 manual

"On TURBO CHARGED vehicles:
Install the bung downstream from the turbo before the catalytic converter. The high exhaust pressure before the turbo interferes with the lambda measurement and the high exhaust temperatures encountered there can damage the sensor."

IIRC the WB shouldn't be subjected to more than 500deg C, I'm sure it said this in the LC1 manual but I cant find it now.

usually putting the sensor about 5" after the turbo will be ok, but thats on smaller 4 cyl's, a big v8 might make more heat.

Also if your using a divorced wastgate the dump pipe must be routed in well after the WB as that style of wastgate leak air to the exhaust path to keep them cool which will obviously casue a lean reading if picked up by the WB.

 

OK, very useful info! I will use my o2 sensors in the 5" down-pipes on each side... All the more reason to have an EGT on each cylinder header primary to help with tuning.... I am not going to change my fuel delivery from a crarb or TB EFI based on an average of 4 cylinders, it is so vague. The actual temp of each primary seems much more reliable...

 

Uhh, what? How can they leak ambient unpressurized air into a system that is typically seeing twice as much pressure as the engine is boost?

 

5" is pretty close .

I would go around 18" or more .

 

Aem recommended 18" from the turbo.

 

Never been a fan of EGT unless you use other methods to verify the results, its nice to have but if you cant/wont read plugs its a waste of time since plugs are the only thing that actually "sees" whats happening in the cylinder.

The EGT can tell lies, so can the wbo2.

 

they leak into the exhaust pipe not the manifold, so boost pressure against what little pressure there is in the exhaust pipe.

 

Still makes no sense to me. Show me a wastegate you are talking about doing this.