Dyno sheet - torque all over the place and low !

[garry goodall]

Cars not been running very well for a while now, took it to a local garage and this dyno graph is the result





he checked the ignition with a scope and found no issues, the fuelling also looks to be good albeit a tad rich

the bloke thinks this may be a mechanical problem, such as the valves ?

Mods are Induction filter, uprated smic, decat, and manual boost controller set at around 14.5psi

makes full torque at rev limiter lol ignore the rev scale it must be out as he didnt have ignition hooked up for true rpm and says 7800rpm rev limit

[Marf]

Your boost controller is not holding boost constant.

Look at the boost values, they are why your torque figure is all over the place

[garry goodall]

am sure thats what its supposed to look like isnt it? it doesnt look like its all over the place on the second picture (bottom), i think its the scale he has used to show the boost on the graph

[garry goodall]

Also is this calc torque or measured ?

[asdrewq]

Can you get it done anywhere else? Those flywheel figures are way too high for the measured wheel power.
Can you feel that wavy torque line with the old butt dyno or hear any turbo oscillation?

[garry goodall]

I can feel it juddering as I accelerate if that's what you mean ? What do you mean by oscillations ? Starting to annoy me now what could be causing this lack of power and torque inconsistency?

[Marf]

How old are your ignition components? plugs, leads, dizzy cap etc?

[asdrewq]

Does it sound like this under boost:

http://www.youtube.com/watch?v=nCj6Spwl1CU

[Kongaroo]

What has the car been doing to make you say it has been running poorly for a while?

To fair for 14.5psi on stock turbo and with the fueling quite rich (as would be expected on stock ECU) your graph doesn't look that unusual as you are only about 1psi or so above stock boost so your numbers are only a little bit lower than expected. The rev 3 is only around 240bhp at 13psi when standard.

Plus all dynos read slightly differently so are mainly useful for comparisons against itself when you re-run after modification.

Are you using the highest octane fuel you can get? Maybe try filling up on Tesco 99 RON or V-power (98 RON) then going back to the dyno. I would then disconnect the battery+ECU, reconnect them and then re-dyno. If your BHP improves a lot then it could just be knock response from the ECU pulling timing slightly on the previous run - this could cause the wavy power line (also as Marf mentioned already - check your ignition components are healthy and you are not getting misfires when under boost).

Another thing to try while you are there is you could maybe try increasing the boost a little to lean out the AFR as when going much above stock boost the amount of fuel provided from the stock ECU remains largely the same so upping boost should lean you out and yield better results assuming you are not causing knock.

[garry goodall]

Does it sound like this under boost:

http://www.youtube.com/watch?v=nCj6Spwl1CU

No doesnt sound like that, good call though

[garry goodall]

all ignition components are litterly brand new, ignitor+coil, dizzy, leads, and iridium plugs.

I always use a higher fuel grade, the run was done on v power, its interesting you should mention the knock sensor, could it be a faulty sensor then? how would i test it?

What boost would you recommend, i usually have it set up at 1.1/2 bar

I know all dynos are different but it doesnt feel as quick as it was and the car seems to hesistate and bog down, it seems to pick up power and drop and pick up again all the way to the red line (as the graph shows), iam not to bothered about what the cars producing power wise at the moment but would like to get the hesitation fixed , think ill have a read up about the knock sensor and see if its faulty

any ideas are much appreiciated

[Kongaroo]

Knock sensor causing the ECU to retard ignition is a normal safety feature for the car but if you want to check the ECU for error codes I think off the top of my head it is error code 52?

[jimGTS]

Cam and ignition timing?
These been checked?

[garry goodall]

So if it was the knock sensor it would throw a fault light up? can the knock sensor just read high levels and not throw a light up?, how does the knock sensor work?

cam timing is spot on i believe, i can recheck, where abouts are the timing marks on the camshafts/ crank?

I will get the ignition timing looked at tonight, is it 10 degrees btdc at 750rmp or something?

thanks for all the help btw

[Kongaroo]

So if it was the knock sensor it would throw a fault light up? can the knock sensor just read high levels and not throw a light up?, how does the knock sensor work?

cam timing is spot on i believe, i can recheck, where abouts are the timing marks on the camshafts/ crank?

I will get the ignition timing looked at tonight, is it 10 degrees btdc at 750rmp or something?

thanks for all the help btw

If the knock sensor had stopped working you would get an error code flash up on the dash when you bridge E1 and TE1 on the diagnostic port - see here:

http://www.imoc.co.uk/forums/viewtopic.php?t=49912

Certainly worth checking the error codes stored in the ECU anyway

[garry goodall]

all right so ill bridge the pins, did this last week and no codes were stored, always worth a shot though

can the knock be reading wrong and resulting in changed ignition timing or is it like a switch either off or on?

how do I check the timing is correct? turn the crank to tdc and see where the cams are aligned, how do i know if the cams are aligned correctly? i think there is timing marks on the shafts itself from inside the rocker cover but dont really wanna be taking everything off the car, it will never work again lol

[garry goodall]

If the knock sensor had stopped working you would get an error code flash up on the dash when you bridge E1 and TE1 on the diagnostic port - see here:

http://www.imoc.co.uk/forums/viewtopic.php?t=49912

Certainly worth checking the error codes stored in the ECU anyway

just seen a strange coincidence, looking at the link you have put up for fault codes, the knock sensor kicks in at 2750rpm, and thats where my first flat spot on the torque curve begins

[Ren0W]

Mine:

[garry goodall]

we swapping cars then ?

bet you cant make full hp at red line like me haha

gunna make sure cam + ign timing is correct, if they are gunna replace knock sensor unless any other ideas?

[garry goodall]

see curve easier on this one