706 replies to this topic

[Exmantaa]

I personally think it's something hidden in the software that Peter hasn't mentioned. He does this for non forged engines as a fail safe. I'll be contacting him today as mine drops off at about 6800rpm in the same rate as Martins. Peak power was at 6800rpm also.

 

That would be a bit duff if there is a 2nd soft limiter in the software that we cannot change...   (Not sure if they did contact Peter about this problem above 7K, but I've seen more OBD powerlogs that tail off at high revs.)

 

 

Just a other idea in the mix Is it possible there is some kind of resonance happening and causing issues

 

Would be a bloody hefty resonance issue causing this power drop and it's not that he has build something exotic. Only a freak resonance in the valvetrain could maybe cause something like that, not intake/exhaust related.

 

The list of possible causes is for us to shoot at, so we will end up with a small To-Do list, starting with the quick and simple things. (Swapping parts & sensors first...  After contacting Peter about a possible OBD soft limiter !!)

 

Edited by Exmantaa, 12 October 2015 - 02:20 PM.

[fezzasus]

Just a other idea in the mix Is it possible there is some kind of resonance happening and causing issues

 

Not really an issue in forced induction. 

[MartinS]

I upped the rev limit to 7800 see if there was a 500 rev length soft limiter but it still tailed off at 7000.

My next planned task is to get a new pcv valve fitted when the new one arrives, probably early next week as want to try to solve the oil burning problem, then will tackle the power drop off.

I am running the 6 plugs with a .8mm gap.

 

I have only done about one hours driving doing ignition and knock learning as opposed to 10's of hours of fuel learning so maybe I should also do a bit more of that.

There is no way my car is running lean, if anything I would say its running notably rich, but this may also be affected by the disappearing oil.

 

Martin

 

 

 

[CHILL Gone DUTCH]

Can you match the plugs you took out to this table Martin

[CHILL Gone DUTCH]

Are you running NGK plugs ?

[MartinS]

NGK plugs would have to take them out see exactly which ones (I know there 6's) but were fitted by Vocky when the engine was done, too do a proper plug check would have to do a plug chop at some time.

 

 

Martin

 

 

[The Batman]

Rmemeber don't fit z22 plugs

[siztenboots]

are saab tapered , or like the z-let/cosworth ones

[CHILL Gone DUTCH]

Yep same plugs as a turbo

[Rosssco]

are saab tapered , or like the z-let/cosworth ones

 

The Saab plugs are flat washered (like the Z20LET yep), the Z22SE plugs are tapered..

[The Batman]

Yup you can fit z20 ones

[MartinS]

[font="arial, helvetica, sans-serif;"][color=rgb(255,0,0);]1/- exhaust restriction [/color]- U bend and backbox size / type ? > should show in his log as a rise in MAP, but that is flat @ ~195KPa[/font]

[font="arial, helvetica, sans-serif;"]Martin  S   Checked and all seems good. With the old restrictive middle section the car produced 260 bhp its no better than that now and has a bigger better centre section.[/font]

 

[font="arial, helvetica, sans-serif;"][color=rgb(255,0,0);]2/- intake restriction?[/color] - alloy tube fitted so not sucking in, but air filter size ? > should show in his log as a decrease in MAP, but flat @ ~195KPa[/font]

[font="arial, helvetica, sans-serif;"]Martin S   Checked, old air filter back on, no worse, possibly better than the Apexi.[/font]

 

[font="arial, helvetica, sans-serif;"][color=rgb(255,0,0);]3/- too high IAT's, causing ecu to retard ignition and loosing power?[/color] - quite possible > IAT's during that run are not excessive. Also Ignition advance is constant in the log[/font]

 

[font="arial, helvetica, sans-serif;"][color=rgb(255,0,0);]4/- too much knock, causing ecu to retard ignition[/color] (there is ~3 degrees knock >5K...) - this needs looking into > Ignition advance is constant in the log up top, but his log shows knock and maybe there is some ecu failsafe action going on at high revs? => revise ignition map with less advance and test.[/font]

[font="arial, helvetica, sans-serif;"]Martin S   Need someone like Vocky to check this I guess?[/font]

 

[font="arial, helvetica, sans-serif;"][color=rgb(255,0,0);]5/- Soft rpm limiter in action?[/color] - needs checking > He already upped his hard rev limit with no change...[/font]

[color=rgb(255,0,0);] [/color]​Martin S   Has anyone asked Peter about this?

[color=rgb(255,0,0);][font="arial, helvetica, sans-serif;"]6/- Sparkplug or Ignition coilpack issue? [color=rgb(0,0,0);]Possible, but less likely > He changed plugs with no results. Should try out a known good coilpack to rule that one out..[/color][/color][/font]

 

[font="arial, helvetica, sans-serif;"][color=rgb(255,0,0);]7/- Fueling issue (pump / injectors)?[/color] - aftermarket pump fitted - is it duff ? - fuel pressure needs checking > Any lack of fuel should show as a lean mixture with possible knock etc. He has no wideband fitted, but his O2 sensorshows 1,1v, which indicates a rich mixture..[/font]

[font="arial, helvetica, sans-serif;"]Martin S My car stinks of fuel apparently if your following me which could we a mix of fuel and oil. The exhausts used to be grey with the ecotec and are no permanently dark with soot weven after a track session. It is running rich.[/font]

 

[font="arial, helvetica, sans-serif;"][color=rgb(255,0,0);]8/- valve / cam problem?[/color] (cam timing / valve float?) - vernier'd cams and dbilas springs fitted > Easy check if springs and lifters etc. are still OK?[/font]

​Martin S   Need someone like Vocky to check this I guess?

[font="arial, helvetica, sans-serif;"][color=rgb(255,0,0);]9/- Mechanical engine problem?[/color] (should be audible and cause high friction lossesn/engine temps me think?) - possible, but less likely[/font]

 

[font="arial, helvetica, sans-serif;"][color=rgb(255,0,0);]10/- Engine electrical / sensor issue?[/color] (maybe external crank trigger looses the plot at high revs?) - solid mounting bracket for crank sensor, but a possiblity > Can be a gap issue with the VR sensor & trigger wheel, only playing up at high frequency / revs... (what's the gap?)[/font]

​Martin S   Need someone like Vocky to check this I guess?

 

[font="arial, helvetica, sans-serif;"][color=rgb(255,0,0);]11/- PCV oiling issues / blowby playing a role here too?[/color] - certainly possible, temporary fix - blank off PCV port under cam cover. > Try this...[/font]

​Martin S   Am getting the old pcv taken out an a new one fitted.

 

Though my car is going through oil faster than I drink beer, the back of the car is clean, no soot no mist of oil.

I had all the underneath off at the weekend and no oil spillages.

Martin S

[fezzasus]

Martin. If you have the crankcase breather venting to atmosphere rather than back into the inlet manifold, do you still see the dip in power at high rpm?

 

Thought process: if significant oil vapour is produced at high rpm, the air charge going into the combustion zone will be mostly oil vapour and make for very different combustion conditions than with fresh air and fuel.

Edited by fezzasus, 14 October 2015 - 08:59 AM.

[Exmantaa]

I think Chill can revise your ignition map a bit to combat the knock that is present >5K rpm.

And for all mechanical related things, contact Vocky as he build it?

 

And did you guys already contact Peter about this power loss?? I just saw the graph of Artic monkey in the B207 thread and that one has exactly the same tailing off power at high revs as Martin's...

[CHILL Gone DUTCH]

I did ask Martin to do a knock/retard learn session But not sure it was added effectively or not at all Unless the knock in the power runs was caused by the road or banging on the chassis

[fezzasus]

Consider softening the dampers for the knock measurements.

[siztenboots]

plus I run with much higher tyre pressures when doing a map check, you really do need the smoothest road possible , or hand tune the results afterwards.

[MartinS]

PCV change next, knock and ignition runs to and from Back on track planned (90 miles worth).

After that will do new power runs and log runs.

Have just written to Peter re a possible 2nd limit in there somewhere.

 

Martin

 

[CHILL Gone DUTCH]

Wideband Martin ?

[smiley]

And did you guys already contact Peter about this power loss?? I just saw the graph of Artic monkey in the B207 thread and that one has exactly the same tailing off power at high revs as Martin's...

 

Same with mine. (cut off set at 7600, yet drop at 7k)