The setup:
freshly rebuilt w/ stock internals KA24DE-t
GTiR T28 w/ SR compressor housing upgrade
.5 bar / 7.25psi boost (controlled by hks actuator)
370 SR injectors
24x7x3 fmic
3" turbo back exhaust
Clean stock KA maf
z32 fuel filter
255l pump
93 oct (only) Shell or Chevron gas
txs knocklite (set on 4 from the highest sensitivity setting)
AEM wideband (logs ~11.6 - 12.1 under boost)
The problem:
8* at peak to avoid detonation; It just seems to be a LOT of timing taken out for such a low boost setting.
The question:
Is this normal for a simular setup? I want to run ~13psi (have to upgrade maf and injectors first tho) but it looks like I'll have to take timing down to 0* or even something atdc @ those levels...
I'm not running lean, but could maxing out my maf (4.82v) cause this?
Sry for such a long post... but thanks for any tips or suggestions!
looking back over the log, I'm thinking maf, and not so much timing now... what do you think?
Pulling TONS of timing out to avoid det... is this too much?
Moderator: Matt
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Pulling TONS of timing out to avoid det... is this too much?
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Hmmm, I do not know the KA24 but what if you look at the SR20DET at those levels (this must be the stock map)?
The suggested fuel from Nissan would be 95 octane for stock (european map of course) and we drive 98 octane to avoid knock if we raise the boost pressure to max. 0.9 bar with the original 370 ccm injectors and the original Nissan Map, even with such mods as the 255l/h Walbro fuel pump.
I think that 93 oct is a little bit to low for aggressive ignition settings. But I can be wrong of course...
The suggested fuel from Nissan would be 95 octane for stock (european map of course) and we drive 98 octane to avoid knock if we raise the boost pressure to max. 0.9 bar with the original 370 ccm injectors and the original Nissan Map, even with such mods as the 255l/h Walbro fuel pump.
I think that 93 oct is a little bit to low for aggressive ignition settings. But I can be wrong of course...
Nissan S14a (SR20DET) :-)
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Re: Pulling TONS of timing out to avoid det... is this too m
I'd suspect false knock.
Honestly read about knock lights etc.. they don't really work that well and give alot of false positives.
Are you running 12.1:1 AFR when you're knocking? Try running 11.5.
Have you pulled your plug after you supposedly knock to see if you are indeed knocking?
Honestly read about knock lights etc.. they don't really work that well and give alot of false positives.
Are you running 12.1:1 AFR when you're knocking? Try running 11.5.
Have you pulled your plug after you supposedly knock to see if you are indeed knocking?
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the KA24de is not a turbo engine in stock form, being so it has a higher CR than the SR. So with my KA having stock 9.5:1 pistons, I'm not sure how close the detonation threshold will be between the two... But it may give me a better idea of how to map my IGN so I'll defiantly take a look at it.
as far as the fuel goes, we have a different grading scale than you guys. 93 is the highest fuel grade we have without using E85 or race gas.
Thanks for the input. Keep them coming, please!
the only bad ideas, are the ones left unheard. Well, sometimes...
a nice IGN map for a similar setup (KA24) would be awesome just to compare.
as far as the fuel goes, we have a different grading scale than you guys. 93 is the highest fuel grade we have without using E85 or race gas.
Thanks for the input. Keep them coming, please!
the only bad ideas, are the ones left unheard. Well, sometimes...
a nice IGN map for a similar setup (KA24) would be awesome just to compare.
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- Joined: Sun Feb 08, 2009 11:44 pm
- Location: Waycross, GA
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Re: Pulling TONS of timing out to avoid det... is this too m
The detonation is audible. I have a really quite exhaust so I can hear most engine noises to an extent. Lots of diy tuners have used the txs knocklite with great success. I agree that its not a dyno, but its better than nothing... I'm just trying to do the best I can with what I have at this point.modulation wrote:I'd suspect false knock.
Honestly read about knock lights etc.. they don't really work that well and give alot of false positives.
Are you running 12.1:1 AFR when you're knocking? Try running 11.5.
Have you pulled your plug after you supposedly knock to see if you are indeed knocking?
If you'll look at the log, when i let off the tps, I had just come into det. my afr's are 11.6 - 11.7 when I jump off the throttle. But my maf is @ 4.82v. But its not leaning out... Still confused.
I havent checked the plugs in a few days, so I'll do that tomorrow.
Thanks!
MAF should be ok for 8 psi. I (somewhat) successfully ran 12 psi on stock MAF. At 12 psi it will burn up in weeks. I ran 8psi with no problems for about a year. So that shouldn't be affecting your tune.
It is possible that you have some crappy fuel. I have noticed that the fuel varies greatly all over the country.
I would pull some more timing from the area of the map in question and see if that takes care of the knock.
It is possible that you have some crappy fuel. I have noticed that the fuel varies greatly all over the country.
I would pull some more timing from the area of the map in question and see if that takes care of the knock.
ya if you are using a type 4 board i dont think matt has figured out the knock feedback but usually what happens is u pull timing under boost anything before peak torque then can slowly add some back to keep hp numbers up after that but knock will be heard on most cases and usually can be seen on the plugs but false knock is common threw the knock sensor