Ignition Advance At Full Throttle - Rb25det With 18psi And >240rwkw

[benl1981]

R33 Rb25 running GCG turbo. Been getting some knock - though not very consistent.

18psi (tailing to 16psi). Made 247rwkw. Was getting readings of 90-100 knock around 5000rpm - 6000rpm under full throttle. Pulled 2 degrees out of most of those cells. These were load point 16 (using z32 afm).

Most of those around around 15 deg advance now.

Just lately noticed some knock around 4000rpm in 3rd and sometimes 2nd. I've pulled out about 3 deg around that zone. When it's at 3500-3700prm it's at load point 16 so I've only altered load point 15 and 16 around that zone. I've also pulled 1 deg out of a few cells close by in case it's passing through there.

Thing was it wasn't pinging on the dyno. Don't know if it's just mechanical noise or what. Thought it might be a bad batch of petrol but it's been on 2 tanks now, and it has always had the tendancy to flash the check engine light (knock oer 60) every now and then (not consistently).

Can somebody post their ign map with similar mods - would like to see if mine was a bit agressive. Around 5000rpm it had about 16 deg previously going up to 20 deg at 6800rpm.

Dyno was done in summer about 27 deg, would think now being cooler would not be an issue at all..

All ignition no.'s in the attached are before touching the tune myself, the negatives are the corrections I have made (I have made more since), to bring a lot of load point 16 no's back to ignition advance values of 14 or 15..

Ignition_map.pdf

[Guilt-Toy]

If i was you i would go see a tuner who has some chasis ears or a really good knock listening device who can check it on the dyno and the street for you.

I hate knock sensors.. mine do all kinds of crazy things as well

[RBwhatever]

R33 Rb25 running GCG turbo. Been getting some knock - though not very consistent.

18psi (tailing to 16psi). Made 247rwkw. Was getting readings of 90-100 knock around 5000rpm - 6000rpm under full throttle. Pulled 2 degrees out of most of those cells. These were load point 16 (using z32 afm).

Most of those around around 15 deg advance now.

Just lately noticed some knock around 4000rpm in 3rd and sometimes 2nd. I've pulled out about 3 deg around that zone. When it's at 3500-3700prm it's at load point 16 so I've only altered load point 15 and 16 around that zone. I've also pulled 1 deg out of a few cells close by in case it's passing through there.

Thing was it wasn't pinging on the dyno. Don't know if it's just mechanical noise or what. Thought it might be a bad batch of petrol but it's been on 2 tanks now, and it has always had the tendancy to flash the check engine light (knock oer 60) every now and then (not consistently).

Can somebody post their ign map with similar mods - would like to see if mine was a bit agressive. Around 5000rpm it had about 16 deg previously going up to 20 deg at 6800rpm.

Dyno was done in summer about 27 deg, would think now being cooler would not be an issue at all..

All ignition no.'s in the attached are before touching the tune myself, the negatives are the corrections I have made (I have made more since), to bring a lot of load point 16 no's back to ignition advance values of 14 or 15..

Sorry I don't have a direct reply for your post ignition wise.

But my general thought is that it is better to tune in winter. Because the air is colder and denser hence more oxygen enriched. So if you had your tune done in summer when its not so cold, the air then isn't as dense and your tune is suited to summer only. When winter comes around the air is denser and it would actually cause your car to lean out because it takes in more air than mapped. And when it leans out it can make it more prone to knock.

So, If you tune in winter you should rule out the possiblity of knock in summer because the AFR's will be richer in summer than winter.

But if you tune in summer, It will lean out in winter because your AFR's will be leaner due to more oxygen, thus knocking in winter.

Someone correct me if otherwise, but its worked for me so far.

[Sydneykid]

I have always found it necessary to take a couple of degrees of timing out of a dyno tune for track work. That's even allowing for the fact that we use chassis ears during tuning. On the dyno the controlled load limits the engine to increasing rpm at a slower rate than what we get on the road/track. Plus the dyno runs are done in 4th gear, which is even more of a even/smooth loading rpm increase than say 2nd or 3rd gears. The real world, faster and less even rpm increases manifest themselves as a propensity to knock. Hence taking a couple of degrees out is a good idea for road cars. For the race cars we tune using 98 ron on the dyno and then run 100 ron on the track, that seems to be an effective way of avoiding the knock problem. Most tuners I speak to do the same.

Cheers

Gary

[benl1981]

Thanks guys.

It has been to a good tuner (Well I think he is). Maybe the cooler weather is playing a factor and what SK is saying about the loading type.

Does anyone with similar mods know what kind of timing they are running around that load point (16). Around 4000rpm are you only feeding in about 14 deg also?

Seems a bit on the low side. I've taken up to 3-4 deg out at some points. I saw an 85 today. Even when it's hit 100 I can't hear anything..

I have taken the air snorkel off - wonder if sucking hot air from the engine bay is doing anything (though the modified snorkel is restrivtive after 5500rpm).

Cheers

[RBwhatever]

You've probably already read pauls PFC FAQ about getting rid of knock by reducing timing etc. As easy as it is to do, its hard to do by yourself.

Unfortunately you can't exactly just "compare" maps with people who have similar mods and power output. Car A and car B may have the same mods and power output, but the maps will be different for both. No 2 engines will be the same.

The best thing for you to do is to get it checked by your reliable tuner and just clean up the maps a bit, it shouldn't take him all that long as the majority of the tune is already done. It just needs some tweaking.

[paulr33]

from the tunes i have seen and all the guys who have asked me or pm'd its very common to see knocking on the street after a dyno tune

it seems when a user loads it up in 2nd/3rd gear on the road the load axis is ever so slightly different than the WOT runs on the dyno in 4th

so they touch a few different cells, which is enouggh to throw knock past 60 and bring on the engine check light

my usual advice includes to read the FAQ and learn how to back out timing and using map tracer to detect where the knocking is coming from

i always warn my guys that knocking is real and dont ignore it, if you see knocking typically on full 2nd/3rd WOT runs (as most guys do) to back off and fix it

if they cant fix cos its too hard or they are scared to use the hand conrtoller then i suggest reppeatedly to go show a tuner and show them when it occurs

or ideally take the tuner for a trash on the street to demonstrate it - cos if they plonk it on the dyno in 4th it will be fine + wont fit those cells

if any of my guys had a 98 ron dyno tune and all was well and they were going to do a track day

i would suggest repeatedly to run 100ron purely for safety / anti detonation killer

more as an insurance purpose. if something is gonna fail / go bad its gonna be

a few laps of a track with excessive temps and lots of WOT load - so 100ron is a good fix / workaround

if they refuse 100ron then i suggest to back out some timing even 2deg using the temp IGN adjust can be enough to save an engine on a few track trash laps

[benl1981]

Yeah thanks - I've used the map trace and I understand that all engines are different, but I just wanted to see someone that had a similar turbo what sort of timing they're running, more for curiosity's sake.

Paul - I like your idea re. the 100 octane shell on track day. I have done that before and it seems to keep knock levels at bay..

Thanks

Anyone with any maps or comments re. 4000rpm load point 16 ignition timing levels?

[benl1981]

Well if I knock out another 2 deg of timing I can keep knock below 50, but that means that around 4000rpm-6000rpm I am only runnning 12-13 deg of timing (in the load point 16 and 17 cells)..seems very low?

Wish theyd start running ethanol in the 98 octane (like the boost98), then it probably wouldnt be an issue..

Might try another batch of petrol and new fuel filter..

Edited August 8, 2008 by benl1981

[Guilt-Toy]

every engine is different. I have tuned cars that have had 30deg of timing on 20psi and i have tuned cars that cannot take more then 8deg of timing on boost.

Every engine is different. So no its not low. Its just what your engine needs to run correctly.

[DECIM8]

I dont know if you read my post but my controller was reading 90-125 and I found out it was a matter of disconnecting the controller, starting car and idle it for 20 seconds, shut it down, reconnect and go for a spirited drive..

After this had no issue, Supposedly something to do with datalogit and PFC controller... plugged in at once.

Try it cant hurt.

[paulr33]

I dont know if you read my post but my controller was reading 90-125 and I found out it was a matter of disconnecting the controller, starting car and idle it for 20 seconds, shut it down, reconnect and go for a spirited drive..

After this had no issue, Supposedly something to do with datalogit and PFC controller... plugged in at once.

Try it cant hurt.

this is a load of nonsense, doing the above will achieve zero

if the hand controller is displaying knock, the engine is knocking

you have one or two cells that have too much timing, simple

[180or200]

I dont know if you read my post but my controller was reading 90-125 and I found out it was a matter of disconnecting the controller, starting car and idle it for 20 seconds, shut it down, reconnect and go for a spirited drive..

After this had no issue, Supposedly something to do with datalogit and PFC controller... plugged in at once.

Try it cant hurt.

only works if you stand on one foot and stick your tongue out!

more than likely it knocks because its loaded up with shit from driving like a pussy, first blast cleans it out then it's all good.

[DECIM8]

this is a load of nonsense, doing the above will achieve zero

if the hand controller is displaying knock, the engine is knocking

you have one or two cells that have too much timing, simple

Thanks fool your the bloke who said it was the cause!!! obviously your telling me everything you've said was dribble.

You said directly the cause was running Datalogit and handcontroller side by side.. Anyway I have not seen knock over 20 so its fixed.

Edited August 8, 2008 by DECIM8

[R31Nismoid]

^^ Paul is probably assuming benl1981 is not running the datalogit & H/C at the same time.

So his response makes sense, yours does not really.

[benl1981]

Thanks guys. Yeah I have hand controller only. Wonder how much power I've lost by knocking out ~4 deg timing. Still feels really quick.

I do know that if you dont get a good start - just let out clutch and floor it, until you hit a good amount of boost at about 4000rpm in 1st its no quicker than a v6 commo to about 40km/h. You really need to rev it a little off the mark to get a decent start. Stock turbo might have been slightly better for this