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General Car Related Discussion.To discuss anything that is related to cars and automotive technology that doesnt naturally fit into another forum catagory.
As some of you know i attended a RR Day @ TOTD yesterday.
From 5800rpm until 7500rpm the engine just flat lines, the power only varies 1 or 2bhp over this range. The boost drops 2.5psi over this period from 22 to 19.5.
Can anbody explain to me whats going on (Chip etc)
The AFR dips from 11.0 @ 6200rpm to 10.5 by 6500rpm then climbs slowly to 11.1 by 7500rpm
The AFR is a constant 11.0 before that point under full load.
Ithink you need to find out why it wont boost no more than 22psi, lets face it my first T3 that came with my car used to boost and hold more pressure than your T34.
Cams are standard and cam timing was only checked less than 750 miles ago, also all sensors checked and boost leak test completed.
A small boost leak was found on the dump valve which has been changed
Cams are standard and cam timing was only checked less than 750 miles ago, also all sensors checked and boost leak test completed.
A small boost leak was found on the dump valve which has been changed
Steve
I don't know much about Cossie tuning to be honest, but I think its a cam issue. You got the graph you can post up?
Although its richer now than before, it doesnt look enough difference to give a 20% difference in top end power, and I cant imagine stu would have made the timing massively oversafe at the top end either.
Looks like a drop in actual VE for some reason, is the turbo ok, no play in the shaft etc?
Although its richer now than before, it doesnt look enough difference to give a 20% difference in top end power, and I cant imagine stu would have made the timing massively oversafe at the top end either.
Looks like a drop in actual VE for some reason, is the turbo ok, no play in the shaft etc?
The turbo is fine Chip, no play in it at all.
If you study the boost curves top end you will notice the turbo holds more boost.
My feeling is that one ran it in 4th (Surrey I think) and the other in 3rd.
I can see a reason why it wouldn't have held boost as well as it might have, but I don't want to discuss dyno operators procedures on an open forum as I know both of them.
Holding boost doesnt always mean the turbo is actually working well though, if the actuator is shut and ALL the engines exhaust gas is having to go through the turbo to make it spool it can cause a drop in power even with the same boost, as its working harder to get it.
Not saying that is happening, you really cant tell just from a graph, Im just offering up suggestions of things you could check.
Stu is the person's input that is required, as he is familiar with the car and knows what map its on, im sure he will be surprised to see it with that much less power!
My feeling is that one ran it in 4th (Surrey I think) and the other in 3rd.
I can see a reason why it wouldn't have held boost as well as it might have, but I don't want to discuss dyno operators procedures on an open forum as I know both of them.
Clearly run in different gears, but that shouldnt make that much difference to power.
After all if it does, it means the rollers are innacurate if they will only work with one particular gear ratio, as what would happen if you were on a different ratio gearbox, lol
No dont leave it, educate us, why should a set of dyno dynamics rollers read out by a massive amount because they are in a different gear, the engine still has the same power, the rollers know what the gearing is (they can see roller speed and engine speed), so why would they be totally inaccurate in one gear and accurate in another?
Im sure that has nothing to do with why my power flat lines.
Sensor was placed on N/S of slam panel
Steve
More then likely not!although as i said to ya on msn,I am sure u would feel the difference of 50 odd bhp!must be a dodgy reading?Plus torque of the devil have not got the best of reputations at the mo!
First step for me would be to give Stu a quick bell. Your old setup may have made 371bhp but might have been detting its tits off on high boost so he might changed things to prevent this.
what in general terms is regarded as safe afr on full boost?11 odd?why can u not run a cossie in the 12,s?as this is still rich with regards to the ideal mixture ratio
what in general terms is regarded as safe afr on full boost?11 odd?why can u not run a cossie in the 12,s?as this is still rich with regards to the ideal mixture ratio
You can, lots of people run their cossies in the low 12s without a problem.
Obviously your margin for error is then a lot smaller than in the 11s though!
29-03-2009, 05:43 AM
Power Flat Lines(Graphs added)
