Knock issue

Discussion of tuning specific to MAZDASPEED3/MAZDASPEED Axela/Mazda 3 MPS vehicles
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skiptownmcat
Posts: 383
Joined: August 3rd, 2011, 11:29 am

Knock issue

Post by skiptownmcat »

If I go wot from anything under ~4500 to redline I get no KR reported but if I go ~50-75% throttle then go wot after 4500 I get anywhere between 0-2.2 KR. I have reduced timing and made afr a touch richer but it seems to be staying. Any ideas steve? No log as of yet.
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Steve @ VersaTune
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Joined: March 29th, 2010, 12:58 pm

Re: Knock issue

Post by Steve @ VersaTune »

Could be the CL-OL timers. Are your OL PT Fuel tables similar to WOT tables? You may need to reduce the Max timing rather than the base timing.
skiptownmcat
Posts: 383
Joined: August 3rd, 2011, 11:29 am

Re: Knock issue

Post by skiptownmcat »

The ol pt fuel targets are richer than wot tables, I just copied the table from the new high load tune. I have the max timing set to stock level. I'm pretty sure I'm in ol when this is happening, even at 50% throttle I'm asking for 1.8 loads.
Maybe I'm just asking for too high a load and it's overspooling at the top and running out of efficiency? copy of tune attatched
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mituc
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Re: Knock issue

Post by mituc »

I wasn't paying attention to the posts I wasn't interested in for a long time now, but I assume you changed your injector seals already, yes? Or you did not and still experience that crazy KR which you want to believe it's tolerable up to even 5 degrees?
2008 Cosmic Blue Mazda 3MPS
Built engine + WMI + GTX3071 gen2, ~509BHP @34PSI
2008 Icy Blue Mazda CX7
Stock engine and exhaust (YES!!), JBR3" + GTX2867 gen2 + Autotech HPFP, self-tuned to 330-ish BHP
skiptownmcat
Posts: 383
Joined: August 3rd, 2011, 11:29 am

Re: Knock issue

Post by skiptownmcat »

Heres the strange thing, part throttle knock is still the same. WOT knock has now dissapeared! Afaik, the loads at part throttle aren't enough to affect the injector seals. Although they are on my todo list
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mituc
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Joined: December 17th, 2011, 2:47 pm
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Re: Knock issue

Post by mituc »

Maybe if you enriched the mixture a bit the cylinders cool down a bit faster and the cylinder pressure diminishes quicker after the initial boom. But I still think it's the injector seals, or some of them not all. Your car has pretty much the same mods I have and you were still experiencing knock with the same mods and tune as I was using... we're also using gas of equivalent quality. But you had that stutter in high gears at high load and that crazy knock, and these symptoms are consistent with injector seals problem - I think.

I'm not a specialist, but this is what I think so you should have someone listen for light rattle/knock from the intake manifold at idle (I hope the noise the blown injector seal(s) make will be loud enough to hear over the fuel pump rattle) and have this possible issue eliminated.

Btw, did you see the toyota injector seals on msf, for like $10 a set? :) So we don't need to spend $200 on the cp-e now unless, of course, we aim for 500bhp.
2008 Cosmic Blue Mazda 3MPS
Built engine + WMI + GTX3071 gen2, ~509BHP @34PSI
2008 Icy Blue Mazda CX7
Stock engine and exhaust (YES!!), JBR3" + GTX2867 gen2 + Autotech HPFP, self-tuned to 330-ish BHP
skiptownmcat
Posts: 383
Joined: August 3rd, 2011, 11:29 am

Re: Knock issue

Post by skiptownmcat »

I didn't see them, can u link me?
I thought injector seals made quite a loud popping noise, easily audible over the noise of the engine when driving?
The part throttle KR is consistent with countless descriptions on countless threads on msf, it only does it when you're off boost and goes away when i put my foot on the accelerator, so I fail to see how that can be injector seals.
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mituc
VersaTuner guru
Posts: 1329
Joined: December 17th, 2011, 2:47 pm
Location: Iasi/Romania

Re: Knock issue

Post by mituc »

Oh, so you got rid of the KR in all WOT situations? Good. I wasn't referring to PT KR which is to be expected in these cars both with the stock or aftermarket tunes (targeting for better fuel economy in CL).
You may not hear the injector seals popping during hard acceleration, but you may feel the car stuttering. However, you may be able to hear the injector seals ticking/rattling at idle or low rpm (car off gear, rev it to 1000rpm and listen).

Here is the link to the MSF forum (I hope it's allowed as we're on a mazdaspeed section): http://www.mazdaspeedforums.org/forum/f ... on-104815/
2008 Cosmic Blue Mazda 3MPS
Built engine + WMI + GTX3071 gen2, ~509BHP @34PSI
2008 Icy Blue Mazda CX7
Stock engine and exhaust (YES!!), JBR3" + GTX2867 gen2 + Autotech HPFP, self-tuned to 330-ish BHP
skiptownmcat
Posts: 383
Joined: August 3rd, 2011, 11:29 am

Re: Knock issue

Post by skiptownmcat »

I'm such a retard sometimes, It came back @WOT but only in 5th gear. I was reducing the timing at the given rpm in the 2.0 row. Then I remembered I have the per gear load set @1.9 in 5th at that rpm. I was reducing the wrong cell!!!
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