Can't get rid of knock Need more idea's

[DJ23GSX]

I am having some knock issues at 19psi and 93 octane that i can't tune out. I am pushing my idc's close to 95% on the 560's @ 42psi bfp and still can't get rid of it. I can't seem to get knock under 12-15 counts no matter how much fuel i add or take away. My mods are in my profile. I would love to turn the boost down but thanks to the great porting from sbr it creeps to 19psi by 5k.

So far i have fixed or tried these things

1. New Knock sensor retourqued a few times with no change in knock
2. New fuel filter
3. Fixed all boost leaks (including the AFPR)
4. Raised my base fp up to 45psi
5. Different 2g mas
6. New plugs
7. Rewired the 255
8. New caps in ecu
9. Air filter box with hose plumbed with ambient air
10. Took foglight out and trimmed the i/c duct to fit the mkiv i/c better
11. Checked the fuel pump seal and cleaned the pump bag filter


I get pk when the car is cold and driving normal but it goes away after the car is warmed up. I don't think its pk i am seeing under boost though as it does go up and down if i add or take fuel away. I just can't tune it for 0 knock. It doesn't seem like i should have to add this much fuel. The next thing i would like to try is bringing my base timing down a bit. I also have a set 650's but i don't think i should need that much fuel for this set up from what i've been reading in other threads with similar mods.

 

[romeen]

Consider water/meth injection.

 

[daren_p]

Looks like your running the supra SMIC? What octane fuel are you running? There could be other sources but I think it may just be the fact your SMIC isn't cooling the intake charge enough. With a previous setup of mine, 18 psi on the evoIII was about the limit I could run with my HRC SMIC before I would see knock. This was on pump 94. Easy way to figure out if this is the cause is to throw in some race gas or some octane booster that works (such as NOS racing formula) & see if your knock goes away. If that the case its probably time to look at upgrading to a FMIC or some meth injection. If you don't want to do either of these you can always remove some base timing but wouldn't be the recommended route since the two previous suggestions will increase performance, while this will reduce it. Another option to reduce timing would be to reduce your base FP, this way you can reduce the amount of fuel your removing with the SAFC, which will give you less timing advance but since your already seeing 95% IDC, thats probably a bad idea as well.

 

[nightspeed87]

yes I agree, you need to get you a nice big short route race fmic kit.
That should allow you to run about 23lbs on pump gas pushing the limit and net you
an overall better tune as to were your not dumping in fuel to compensate.
Other wise your doing good so far in your attempts to fix your problem...
Meth would be a good short cut but not always the best thing for a streetcar that needs
to be consistent. Consider upgrading your coolant system too if you have any heating issues with that because I believe anything over 206 deg will also result in one count of knock being pulled .

 

[DJ23GSX]

I am running 93 octane

I am starting to lean towards heatsoak. It seems like my first 2 pulls of the day i get 0-5 counts of knock and it seems to go up from there. I see around 82% idc's on my first couple pulls and end up around 95-98% after adding fuel to try and stop the knock.

Meth injection has been on my mind for a while so maybe i will go that route.

 

[ghostcar]

i would take a few degrees of timing out and change to a cooler thermostat and see how things progress.
good luck

 

[DJ23GSX]

i would take a few degrees of timing out and change to a cooler thermostat and see how things progress.
good luck

I have a fluidyne radiator and i have only seen temps over 199 a few times in the dead heat of summer.

I believe last time i checked my base timing was 7* but i don't have a timing light so i'm not going to mess with that.

 

[DSM4me44]

Consider water/meth injection.

Thats what cured mine

 

[SBR Joe]

The fact that your out of injector probably doesnt help. Its not a heatsoak issue, i ran 12.4 with my automatic on a 16g, 650's , stock pump and a supra SMIC at 24 psi on turbo blue (ya, it was a track slut and i didnt care). Turn the base FP up to like 50 and see if it helps. if not, id consider an injector upgrade. 95% DC is a lil high. Also, if you have access to it, throw a shot of race gas in to see if it clears it up, if yes, then is a matter of not enough fuel.

 

[SBR Joe]

I am having some knock issues at 19psi and 93 octane that i can't tune out. I am pushing my idc's close to 95% on the 560's @ 42psi bfp and still can't get rid of it. I can't seem to get knock under 12-15 counts no matter how much fuel i add or take away. My mods are in my profile. I would love to turn the boost down but thanks to the great porting from sbr it creeps to 19psi by 5k.

Stock Flapper???



Joe
SBR

 

[gixrman]

Have you tried the foam combustion chamber cleaner? Carbon buildup will cause knock too. That was my problem for awhile.

 

[ypnas777]

What range plug are you using? Consider a colder non-projected plug. Also, since you say the knock increases with the amount of pulls it's probably heat soak so I would upgrade the intercooler or go with water/meth injection. Good Luck!

 

[SBR Joe]

What range plug are you using? Consider a colder non-projected plug. Also, since you say the knock increases with the amount of pulls it's probably heat soak so I would upgrade the intercooler or go with water/meth injection. Good Luck!

Bolt-on Modifications
Ported 16g,Ported 2g exhaust man and o2 housing, 3" turbo-back exhaust, 2g MAS 3" intake pipe with K&N, ACT2600 SS line, MKIV i/c,, SAFC, Evo8 560cc's, 2.5" upper and lower i/c pipes, Magnecor's, bpr7's, Fluidyne radiator, rewired Walbro 255lph pump Aeromotive afpr


Plugs are covered.



Joe
SBR

 

[ypnas777]

Bolt-on Modifications
Ported 16g,Ported 2g exhaust man and o2 housing, 3" turbo-back exhaust, 2g MAS 3" intake pipe with K&N, ACT2600 SS line, MKIV i/c,, SAFC, Evo8 560cc's, 2.5" upper and lower i/c pipes, Magnecor's, bpr7's, Fluidyne radiator, rewired Walbro 255lph pump Aeromotive afpr


Plugs are covered.



Joe
SBR

he could try br7es or br8es.

 

[SBR Joe]

he could try br7es or br8es.

Non projected plugs wont help that much. He shouldt have to run 8's but it would help a bit beings it will burn a bit colder, wouldnt last very long though.



Joe
SBR

 

[Rice Over Wheat]

Get your intake temps down as much as possible by reducing engine bay heat and a cold air box allowing the turbo to pull only ambient air from below the filter (cut sheetmetal around stock smic uicp hole). Try and get intake temps under 100F, anything above and the ecu pulls timing and you are more prone to detonation.

 

[DJ23GSX]

Stock Flapper???



Joe
SBR

Nope 38mm.

I am also running bpr7's

On my first few pulls of the day i am able to lean out the safc and get around 80-83% idc's at 42psi bfp with 0-5 counts of knock. I only see 95+% after the knock starts and i add fuel to try and stop it. Thats why i think its heatsoak. I go from little to no knock to high knock after a few back to back pulls.

Get your intake temps down as much as possible by reducing engine bay heat and a cold air box allowing the turbo to pull only ambient air from below the filter (cut sheetmetal around stock smic uicp hole). Try and get intake temps under 100F, anything above and the ecu pulls timing and you are more prone to detonation.

I have a cold airbox with a 4" hose plumbed under the car grabbing ambient air straight up to the filter

 

[SBR Joe]

Nope 38mm.

I am also running bpr7's

On my first few pulls of the day i am able to lean out the safc and get around 80-83% idc's at 42psi bfp. I only see 95+% after the knock starts and i add fuel to try and stop it. Thats why i think its heatsoak. I go from little to no knock to high knock after a few back to back pulls.




I have a cold airbox with a 4" hose plumbed under the car grabbing ambient air straight up to the filter

If you do like one 3-4th gear puill does it knock? or will it do it only after a few pulls? .....and u mean 34mm flapper..


Joe
SBR

 

[DJ23GSX]

If you do like one 3-4th gear puill does it knock? or will it do it only after a few pulls? .....and u mean 34mm flapper..


Joe
SBR

Yes 34mm Sorry..

I can usually get 2 good 2nd and 3rd gear pulls with less than 5 counts of knock. Once the knock starts it takes forever for the i/c to cool down and the knock to go away.

 

[SBR Joe]

Yes 34mm Sorry..

I can usually get 2 good 2nd and 3rd gear pulls with less than 5 counts of knock. Once the knock starts it takes forever for the i/c to cool down and the knock to go away.

thats odd...i never had an issue with my supra SMIC heatsoaking liek that with pretty much the same mods you have.....but def souds like a heatsoak problem. Whats your intake temps usually at? Also, the one thing i had that i dont think you do, heat wrap. i heat wraped my o2 housing, the dump, had aheatsheild on my manifold and had the piping from the turbo outlet to the throttle body wrapped. thats probably why i had much less heat soak issues.



Joe
SBR

 

[DJ23GSX]

thats odd...i never had an issue with my supra SMIC heatsoaking liek that with pretty much the same mods you have.....but def souds like a heatsoak problem. Whats your intake temps usually at? Also, the one thing i had that i dont think you do, heat wrap. i heat wraped my o2 housing, the dump, had aheatsheild on my manifold and had the piping from the turbo outlet to the throttle body wrapped. thats probably why i had much less heat soak issues.



Joe
SBR

My intake temps at the mas are usually within 5 degrees of ambient temps.

You were running 650's compared to my 560's but other than that the mods are similar. That was a track car right? Did you ever make back to back pulls at 24psi with that setup? I've done some searching and have read a few threads where people claimed to heatsoak the mkiv and have read others that run 20psi daily with no issues.

I have 650's sitting in my basement but i am not sure they would help. I am sure they would probly dump enough fuel to calm the knock down but i am not sure what there going to do to my timing. With 0-5 counts of knock on the 560's i get 19-20* of timing.

All i have is my heatshield over the exhaust manifold i broke the o2 shield and i have no heatwrap on anything in the engine bay.

Say i go with meth injection... Should i stick with the 560's or drop in the 650's? Mind you i only have a safc for tuning. No eprom.

Thanks for the help

 

[nightspeed87]

Adding bigger injectors will raise timing since your tuning with safc which isnt good about 1g timing maps. Have you thought about dsmlink, or an chipped ecu to control those injectors at least? Also warding off any heat in the engine bay will help slightly.
Is your egr valve hooked up like stock? But for the most part you just need a fmic man.
Make sure you dont have any oil going into your intercooler because ive read that that can hurt the intercoolers cooling efficiency. Get a catch can or something for that if you dont have one.

 

[Hop]

I'd install the 650cc then back down the base fuel pressure close to stock. Try to get the IDC no higher than 90%. Leave base timing at 5*. Why did you set it to 7* when your AFC is already adding timing on top of that? Logging 20* when your base is advanced means you're already at 22*. Hell, I run 24* on C16.

I agree on a better FMIC.

The BPR8ES plugs allowed me to run 1-2* more timing but they like to foul. I've gone back to the 7's in my Talon.

[edit] Now I see that it's only 5 counts of knock. Isn't that near nothing for a 1G? At first I thought you meant 5* of retard. Now that would be knocking.

 

[DJ23GSX]

Adding bigger injectors will raise timing since your tuning with safc which isnt good about 1g timing maps. Have you thought about dsmlink, or an chipped ecu to control those injectors at least? Also warding off any heat in the engine bay will help slightly.
Is your egr valve hooked up like stock? But for the most part you just need a fmic man.
Make sure you dont have any oil going into your intercooler because ive read that that can hurt the intercoolers cooling efficiency. Get a catch can or something for that if you dont have one.

I know about the timing issues i would most likely have with the 650's thats why there still sitting in my basement. My egr valve is still hooked up like stock. There is no oil being recirculated through my i/c.

I'd install the 650cc then back down the base fuel pressure close to stock. Try to get the IDC no higher than 90%. Leave base timing at 5*. Why did you set it to 7* when your AFC is already adding timing on top of that?

I agree on a better FMIC.

Get as much of that engine bay heat as possible away from the air filter too.

The BPR8ES plugs allowed me to run 1-2* more timing but they like to foul. I've gone back to the 7's in my Talon.

My idc's with the 560's are only 82% before the knock/heatsoak happens. The only reason they climb over 95% is because i add fuel to try and stop the knock. As far as the timing goes i set the base timing in the datalogger to 7 so it should be reading the correct timing while under boost.

 

[nightspeed87]

I run 850cc injectors like stock...

www.dsmchips.com

with an eprom ecu of course...