I think I know the answer to this....

but.

Mapping a car - should it be done purely on the results of a wideband reading?

 

How are you going to map ignition?

with regards to fuelling though, wideband gets you to where you *think* the car wants to be, ie "I reckon 11.5:1 at 2 bar of boost is a good starting point"
Ideally though, you would then look at EGT's as well, like for example Stu was saying Focus RS need to be a lot richer than a cossie in the same circumstance, so you need to be monitoring other things to know that.

 

it also doesn't tall you that you are getting the best torque that you possibly could - only that you are in the right area

imo, only a dyno can do that entirely accurately. although by using a g-meter (or just a time/distance measurement) on a repeatable stretch of road to measure acceleration can give you some idea

 

"Off topic" Any idea why?

 

i thought this would be the case.

Cheers for clearing that up!

 

restrictive exhaust manifold

 

Although experience of a very similar spec engine can do that

Im sure most of the guys on here mapping cossies for example, know full well what AFR's are going to work on which spec without needing the dyno again and can get ridiculously close to ideal results just from experience/AFR

 

CheeRS Nick

 

i agree - if the spec. is known in detail.

but i suspect the topic starter is asking as he wants to do it himself and doesn't have that experience to rely on

 

Now YOU are making assumptions

He is actually asking because its what someone else has told him that he does, and he was unsure as to wether that was sufficient (I know as Ive just been chatting to him on MSN about it )

 

no, i suspect. not i assume

 

Your suspicion was based on an assumption I suspect

 

however, I am shorty going to be looking to ruin a cavalier sri 2.0 with megasquirt to start me on the slow learning curve to maybe know something about stuff

 

wideband
egt gauge
det cans

is what i use

 

what stuff do you use Jay if you dont mind my asking?

 

chip how do you go about setting up the ignition map? its mike btw we met the other day

 

You put in values you think will be safe as a starting point (based on experience) then you get the AFR's right, then you increase the ignition until you hear det, then you come back a few degrees.
Thats how you do a basic live map anyway.

Things like minimum advance for best torque need rollers, although generally taking timing out till the heat increases (if you have an EGT probe and can hold it on the brakes or similar to load it on a cell for a long time) gets similar results as normally as you move from min advance for best torque you also see an increase in temp

 

Just one of the reasons why a rolling road is better than a live map, you can control every situation and hold under any load any speed any gear, can't do that on the road.
Once mapped though you could run purely on egt, so long as you don't make any changes.
tabetha

 

hummmm sounds good thanks

 

You can control very little on a rolling road. Sure, you can get steady-state rolling roads now which allow you to hold the engine at a target rpm but it's not a touch on an engine dyno.

I've been quite successfully able to hold an engine at a given speed and load on the road as i'm sure most professional tuners have/do...

I think you'd be insane to rely purely on EGT. As with everything, you need as many sources of information as possible to decide what and when there is a problem - relying on one sensor can lead you down the garden path.