Stu @ M Developments

iTrader: (12)

In the downpipe wherever possible, but if not i am quite happy to monitor from the tailpipe as long as the exhaust appears in good condition. With gas travelling at supersonic speeds, there is nothing to choose from between downpipe and tail readings as long as the tail pipe sample tube is correctly designed so as not to draw air in from atmosphere.

mechanic28

iTrader: (5)

cool!had mine done both ways in the downpipe and through the tail pipe

JamesH

iTrader: (21)

Thanks for your input Stu!

Can you give me any more points to try out?

I assume mid 11s is anything from 11.4-11.6? How dangerous is it being leaner than that at the points mentioned?

An 044 fuel pump has been fitted recently too, and the pumps been re-wired since Karl had it.

I usually change gear around 5500-6000rpm because you then just get the boost spike again And I don't cain it everywhere and can honestly say I've never hit the limiter/don't use the really high revs. However I understand that the damage can happen in less than seconds if bad enough; so thank you for your valuable input Stu, and for anymore you can add

JamesH

iTrader: (21)

Right then, just had it out again

Unfortunately even the road we chose we just couldn't get it past 6000rpm in 4th!!

It was holding perfect 11.8 until 6000rpm when it went to around 12.2 and 12.4, and couldn't go higher due to space...

Does 3rd gear not matter as much, just wondering why 4th and 5th seem to be of most relivence?

But I can't think of any scenario where we'd have it above that in 4th (change before 6000 usually as generally don't like giving it to harder time, plus boost spike as mentioned above) and would never go to 6000rpm+ in 5th, it might not even ever get there lol

Would the readings be expected in 2nd/3rd at the same rpm be different?

It cruises at 14 to 14.5

Karl

All sounds fine to me.

JamesH

iTrader: (21)

JUST the man I was looking for!

I will try and ring you tomorrow if thats ok with you Karl... just to check

What sort of AFR would you consider 'dangerous' Karl, as it seemed leaner in 3rd (didn't check 2nd), is there any reason for this, as per my questions previously

Feel free to answer any the of questions, if you have time of course

Karl

Don't worry about your readings too much, most people don't realise that you won't actually get constant readings. When I map a car the fueling is checked by holding the car back on the brakes fully loaded at 1000rpm intervals. In lower gears and during quick bursts of acceleration the AFR will read leaner.

ALso bare in mind that most lambda equipment such as your stack gauge may not be as accurate as my mapping equipment and hence you should'nt worry yourself.

The time to worry is if you see AFR's in the 13's on high boost. Even with a cheap wide band gauge like the stack item, it will have sufficient accuracy to indicate something is wrong if you are seeing 13+ AFR on full boost.

JamesH

iTrader: (21)

Excellent Karl

No need to disrupt you during your working day tomorrow now!!

If we see (hopefully we won't!) 13s on high boost we'll be sure to call

I understand the Stack etc are cheap (relitively speaking) compared to really decent mapping equipment, but thought it'd still be accurate enough to sound alarm bells

Thanks for your time

cossiedave

iTrader: (1)

this is interesting i have 8 greens a t4 and 30 psi and see 10.4 is this really safe

Jay,

iTrader: (4)

you need to phone diva!

Stu @ M Developments

iTrader: (12)

Its not dangerous at all generally speaking. What you ahve to be aware of, is if tyhe fuelling leans to less than it was when it was MAPPED then the spark tale will be incorrect and the increased burn speed of the lean mixture may cause her to detonante and melt down.

Bottom line is, ask your mapper. If he mapped it at 12.5, it will be fine at 12.5. If he mapped it at 11.5, it wants to be at 11.5.



Edit: had i been arsed to read the whole topic before replying to your question, id have seen you already have an answer.

Jay,

iTrader: (4)

really safe mate

cossiemanden

Mine did a 12,2 afr @ 2,1bar with a gt-35 and 22`ignition @ topend
Was fine, no det but i saw 980`in the collector

Bobby Singh

When i had my cossie it use to run 12.5:1 WOT - set up by AB 1.8bar on a T34