Craigorypeck
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| posted on 12/4/11 at 08:18 PM |
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Redlined eventually...
So after a few miles on the car I set the rev limiter to 7500. (YB on zx9r carbs)
The only way to get there is by pressing the throttle in line with the increasing revs.
If I plant the boot from say 3000rpm pinking edges in at approx 4000rpm and is really bad from 4500 onwards.
Afr is 12-12.5 all the way up so i doubt its running lean?
The ignition advance is from TPS and on WOT will be less than the linear action im using on the throttle now so shouldn't be over advanced..?
WOT is set at 23 degrees from 3500 onwards
Any help would be great!
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Chippy
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| posted on 12/4/11 at 09:37 PM |
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Well really only two causes of "pinking", (detonation as they call it now), either incorrect mixture, usually too weak, or ignition too
far advanced. I would say that the latter was your problem, and would reduce down to 20 deg's from the 23, and see how things go then. Only real
way is to shove it on a rolling road, and get it set up correctly. HTH Ray
To make a car go faster, just add lightness. Colin Chapman - OR - fit a bigger engine. Chippy
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Angel Acevedo
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| posted on 13/4/11 at 01:14 AM |
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Up the Octane rating a notch....
Higher Octane will have better performance under WOT....
It may not be enough....
You don´t state the age of the engine...
Carbon deposits on the Combustion Chamber will raise CR and Localized High temperature Spots on Cylinder Head to the point of pinging... but this will
be on old engines.
HTH
AA
Beware of what you wish.. for it may come true....
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Craigorypeck
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| posted on 13/4/11 at 06:40 AM |
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It will eventually be rolling roaded, engine 1000 miles old, cr 11:1.
Have 98 and octane boost in the tank.
I will try bringing the total WOT advance down to 20. it idles at 18!
Cheers!
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MikeRJ
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| posted on 13/4/11 at 09:24 AM |
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18 degrees seems very high for what will be effectively the static advance on a 16 valve engine? I'm surprised the starter motor doesn't
struggle.
By gradually opening the throttle with increasing RPM you are throttling the engine through the rev range, effectively reducing the CR. This points
to either too much CR or too much ignition advance.
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coyoteboy
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| posted on 13/4/11 at 11:06 AM |
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My tintop does this exact same thing, the only solution I found was to drop the advance a little to account for it, or learn to drive without just
hitting WOT right away. Or running v-power and a lesser combination of the above  It's a shame because it really affects the light-throttle
response to drop the advance. I'd like to program into the MS an acceleration retardation much akin to the acceleration enrichment.
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Craigorypeck
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| posted on 13/4/11 at 05:41 PM |
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The cranking advance is 14, the 290 cams should have a static timing of 16?? if so mine is actually a bit high, will bring it down a bit. Hopefully
I'll get the megajolt hooked up later and have another play around..
One concern- Will such little advance on WOT burn the exhaust valves??
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Volvorsport
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| posted on 13/4/11 at 07:03 PM |
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pinking and detonation are two different things .
is the exhaust manifold glowing hot ? whats the total advance ? i think you may need a bit more advance , volvo 2.3 motors can have upto 42 degrees
total advance .
Have you looked at the plugs ? are they fouling 12.5:1 is pretty rich
www.dbsmotorsport.co.uk
getting dirty under a bus
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Craigorypeck
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| posted on 13/4/11 at 08:35 PM |
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Got my computer to connect to the megajolt again... phew!
I got the current map saved and looks like this-
As you can see (barely!) its basically what a vacuum line from dissy would be doing and not a proper map relating to torque figures
With 11:1 Cr I should be on 30 degrees at least full in from 3500 on WOT
Exhaust doesn't seem any hotter than the pinto..
Plugs are clean... too clean I reccon.
I have ordered colder plugs, maybe the ones I have are running a very hot tip and causing detonation?
Have ngk BCR8ES in now gonna try BKR9EIX, should arrive in the post tomorrow.
I will report back with the results.
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coyoteboy
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| posted on 13/4/11 at 08:36 PM |
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Indeed there is a difference between pinking, det and pre-ignition. Anyone that's heard real det will know about it. IME, with my engine, it
sounds like the noise you get when you lob a hefty stone at a thick-frozen lake - that sort of "thhdooiik" noise. You back off the
throttle pretty damn quick when you hear it! The other two just sound like tinkling and are impossible to distinguish from each other by ear.
[Edited on 13/4/11 by coyoteboy]
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MakeEverything
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| posted on 13/4/11 at 09:15 PM |
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I reckon your AFR is weak when you nail the throttle. Do you have a wideband controller to check it? ITs gonna be a real expensive job to repair it.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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mikemph
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| posted on 13/4/11 at 10:48 PM |
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Are the sure the trigger wheel is actual set so it's actual firing at say 25degs when the engine is 25degs. You might need to alter the trigger
offset. Get the timing light and check it if I was you. Some times it's the simple things that get over looked.
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Craigorypeck
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| posted on 14/4/11 at 06:51 AM |
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Wideband in the exhaust manifold, has been free air calibrated twice incase it was wrong.
With engine at 18 degrees on idle, timing light on -18 shines bang on TDC... might get a lend of the timing light again and try it up at 4000 rpm see
if it lines up.
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Craigorypeck
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| posted on 14/4/11 at 06:46 PM |
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Reduced the WOT advance and it seems to handle it a lot better now.. Havent tried the other plugs yet as they haven't arrived. Thanks for the
pointers peeps!
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