knock/tuning guru's need help

[Baron4406]

Ok first off its a 1993 AWD Talon with a 6bolt swap (was reputed to be a JDM motor but more on that later). Car has 560 EVO injectors, big 16G, tubular exhaust manifold, adjustable FPR, Tial BOV, big front mount, full 3" exhaust. I bought the car as a project, it had a very clean motor in it, but cranking compression is 175PSI or higher which leads me to believe it has 2G pistons in it. Car was running a blow thru MAFT setup, is now Running an SD setup with Jackal. Problem? Car knocks. I dont think its phantom knock either because it only happens at high boost, no part throttle knock at all. If I adjust my VE's until I'm in the 9.8's AFR I can make the knock go away. At 10.0 it knocks.I have my timing map scaled WAY back, I have my 11 and 12 scale at 10 degrees from 3000rpm and up and it knocks there too. Thought it might be bad gas, but this is the third tankful and was filled up at a different station. Was suggested it might be rich knock but raising the AFR's to 11 caused more knock. I can run about 13 or 14 psi of boost before it knocks. 16psi is bad, 20 psi is horrendous knock. BTW wideband is an LC-1 running in the stock location, I had it downstream for awhile but moved it to the stock location for more accuracy. I seafoamed the motor last night, no change. Base timing is actually set at 4 degrees. I'm stumped I never thought can car could knock at a 10.0 AFR. BTW the motor is fairly quiet, no lifter tick.

 

[gofer]

What are you tuning with and what OTHER mods do you have done to your car? Thats why in your profile there is a section just for car mods, that way you don't have to post them everytime. As I'm reading the mods that you remembered to throw down in your OP it seems like you might have forgot a fuel pump, unless your running the stocker 1g pump with an afpr and Evo injectors? NOTE Evo injectors are advertised as 560cc injectors however, if you've got them on a 1g running 37psi base fuel pressure they flow 504cc/min.

On to whats going on with your car. If its knocking like crazy with those AFR's it would appear that something isn't right, have you happened to reach around under the IM and check to see if the knock sensor is loose or burnt? There is a torque spec of 17 ft. lbs. on the knock sensor believe it or not, you've just got to use a crows foot to do it...

If your running 91oct your going to see pretty rich AFR's to keep knock to a minimum, of course 9.XX:1 is really rich. If it were my car and I was trying to street tune it I'd back off the boost to run JUST off the wga (12psi) and bring my AFR's to 11:0 ~ 11.2:1 and back off the timing since a 1g's timing tables extremely aggressive. Start from there and get your AFR's and boost where you want without knock and then start advancing the timing a bit at a time.

Good luck and if you can post a log, it will help us help YOU a ton more then just going off of what your saying.

 

[toofast82]

Set your desired boost,
tune your a/fs for 10.6-11.2:1 on pump, 11.8-12.5:1 on e85/race fuel and comfort level
If knock is present, lower timing until it disappears

Tuning is all a compensation game between timing, boost and fuel. Pump gas dislikes high timing and the 1g timing map is overly aggressive for any decent boost

 

[JayRolla]

Kind of like my setup before I went to e85. Have you tried to run the rich 10.0 afr and see how much boost that will take? Maybe try some racegas and if that helps you know its a fuel issue so you can rule all other things out. If e85 is available I recommend converting or trying a meth injection kit.

 

[Baron4406]

Already did all that sorry to say. I've made the timing curve only go to 10 degrees max and at 16 psi boost and an AFR of 10.0 it "knocks" and the EGT's never get above 1400deg. Also getting black deposits on top of my pistons. No sign of detonation on my plugs or piston tops even if I hold it floored "knocking" for a long pull. I just think the knock sensor (its new BTW) circuit is picking up some kind of rattle in the engine thats rpm specific. as far as my fuel pump I get 90% of IDC's at an AFR of 9.5 so I think its ok, dunno what is back there. Car was a big time drag racer at one point.

I wish I could get E85 trust me

 

[rstchris]

Running it pig rich is not the best solution in my oppinion. Like stated above you are going to have to lower timing even more. Try to look for ways to lower intake temps as this will welp. Meth will help very much but using meth for DD is a gamble. Depending on the baro when you did the comp test I don't think they are 2g pistons. 175psi is higher like maybe mid 9s area. That being said you are gonna have to treat it like a non-turbo engine (low timing, low boost) til you get race fuel in it. What IC does it have?

 

[gofer]

From personal experience after I installed a set of FP2 cams I had to change my tune all up to keep it from knocking. On stock cams I was around a 11.0~11.2:1 AFR on 91 octane with 11* of timing advance. After the cams went in I was around a 10.5~10.8:1 AFR on 91 octane with 5* of timing advance. Just drastically reduce your timing advance until knock disappears, then bring it back a degree at a time until you start seeing knock.

A few DSM'rs over on the dsmlink forums put a plastic washer in between the knock sensor and the block, supposedly it won't pick up phantom knock. Just another suggestion...

 

[JayRolla]

2g pistons will test around 175psi. When some buddys did a boosted stock 2.4l galant motor with 9.0:1 pistons it tested around 200psi.

 

[Baron4406]

From personal experience after I installed a set of FP2 cams I had to change my tune all up to keep it from knocking. On stock cams I was around a 11.0~11.2:1 AFR on 91 octane with 11* of timing advance. After the cams went in I was around a 10.5~10.8:1 AFR on 91 octane with 5* of timing advance. Just drastically reduce your timing advance until knock disappears, then bring it back a degree at a time until you start seeing knock.

A few DSM'rs over on the dsmlink forums put a plastic washer in between the knock sensor and the block, supposedly it won't pick up phantom knock. Just another suggestion...

Well that helped alot, with this compression this engine hates timing I found. Lowered it to 5 deg. and even at 19lbs of boost and 10.5 to 11 afr's it wont knock, funny there is a spot at 4500rpms where its loves to knock, I rolled the timing back in at 5000 rpms to 12 degrees and it doesnt knock. BTW raising in fuel pressure messed up my VE table, so I subtracted a huge amount of fuel everywhere. Now my IDC's are in the high 60's and I'm still a tad rich. This is on 92 octane too I went to another station to see if I had bad gas. I'll probably feel better and and play more when I get 93 back in it. BTW I installed NGK 8 heat range plugs and gapped them to .030, I really should be running 7's tho.

 

[gofer]

That was my case as well, between 4k - 4.5k was where it would knock. Since your running a smaller turbo like me, I've found that high timing in the low rpm range will spool the turbo faster as well. Just a little tuning trick I've learned from all the gurus, try it out if the car won't knock on you.

You should really be running 7's and gap them tighter than stock specs, around a .025".

 

[Baron4406]

Thanks for the tip, around here no one has 7's I only had a set of 8's that I found laying in the car. Better than the 6's it had to. I just gapped the 8's a little bigger to help them misfiring at low speed when its cold. Also the lower timing map is still the factory map, Dunno if you familiar with Jackal but it divides the timing into 12 load ranges at 500 rpm increments/ I only lowered the timing in the 11 and 12 rows (full throttle) above 3000 rpms. The factory numbers are still in the lower ranges and in the part throttle load tables (I dont get any knock anywhere else)

 

[JayRolla]

Glad you got rid of the knock. I would really look into a meth injection kit to get some good power out of that car.

 

[Baron4406]

Dunno what I'll do yet but from the look of my logs there's a good bit more boost in this setup im only at about 70% idc's, I'm gonna run it soon to see how it does. I also just filled up with 93 octane i might be able to squeeze out more timing. What im finding bizarre is I did a long 4th gear pull on the highway and found out two things, for one for some odd reason even tho my VE table is flat to redline as i get to 6000 rpm's my AFR's get richer to the point im down to the low 10's. I think this is because I'm losing boost slowly at the high rpm's. I was thinking boost leak but I've tested and retested my motor for that. It might be my manual boost controller. I have a MAC valve and Jackal has an integrated boost controller so i might try that.

 

[gofer]

Your 16g won't hold boost to redine, its just not efficient enough. Most will tell you to shift 200 rpm after your max hp, which on my setup peak hp was at 5.5k and peak tq was at 3.6k. I'd shift at 6k and it would put me right in my peak torque power band, its up to you and you can play with it at the track to see what works best for your setup though.

 

[Baron4406]

Well an update here, trying to run any kind of boost/timing with higher compression is no fun. My high cranking compression (175+ psi) means I'm limited to around 17-18 psi as long as I keep my AFR's in the 10.5 range and keep my timing under control.

 

[Ceddy]

The above conversion chart will give you an idea of what the Load numbers 1-12 represent.

A big problem with the 1G Load axis is about 10 psi and above you are in the same Load column. Also the stock 1G timing map has way to much advance for higher then stock boost or higher compression. With higher boost and higher compression you will most likely run into knock.

If you are getting Tip-In knock(knock at end of spool up, 3000-4000 rpm), just lower timing in that rpm area. The higher compression evos have timing as low as -1 in this area with their stock maps.

You will make more power with boost then timing, if you need to run low timing at high boost, thats what you got to do.

Since you have a high compression motor, you may want to check out the stock Evo8 timing map to get some ideas.

 

[Baron4406]

Thanks Ceddy Jackal does have full timing control over all load areas and I do have knock problems in the 4500 rpm areas. However I also read you will make more power with higher timing rather than lean setups so I've been richening up my afr's (shooting for around 10.5 AFR) and trying to run more timing. So I will probably try your advice and try to back the timing off to run more boost and see what the butt dyno tells me. I honestly wish I could get E85 around here this higher compression motor would be a monster on it. This car is the most responsive DSM I ever drove around town, it actually feel like a healthy V8 cruising around- thanks to the high cranking compression. But at full throttle its a bear to keep it from knocking.
Thanks for your advice I'm gonna try to knock the timing way back and run more boost. I see you right down the road from me too, I assume you knew Wess Hess? He was a pretty good friend of mine before he joined the Air Force and I was experimenting with a 2G head on my 1G for him as a rolling test bed for awhile.

 

[the_mork]

FWIW you are having some issues with the way that you are fuel tuning. When you change your base fuel pressure you need to adjust whatever table affects your injector size because you only want to affect your fueling and not your timing. Changing your VE tables to compensate for injectors is BAD NEWS except in very isolated circumstances because of the effect that that has on timing. If you happen to be dialing in very large injectors you can adjust your VE tables near idle and cruise for fine tuning where scaling and deadtimes have too much effect one way or another.

Short version: changing fuel pressure doesn't affect VE so don't change your VE table to fix fueling changes.

 

[Baron4406]

No large injectors here, all I have are EVO 560's and I have the fuel pressure set to stock EVO pressure (43 psi). Plus Jackal has settings for ejector size and deadtimes so you dont have to mess with your VE when changing injectors.

 

[the_mork]

BTW raising in fuel pressure messed up my VE table, so I subtracted a huge amount of fuel everywhere. Now my IDC's are in the high 60's and I'm still a tad rich.

This is what I was referring to. If you later went back and adjusted this back and made the compensation with your injector tables then everything is happy.

 

[Baron4406]

This is what I was referring to. If you later went back and adjusted this back and made the compensation with your injector tables then everything is happy.

Well Mork the injector tables have settings for deadtimes and CC's, no settings for fuel pressure. So I had the correct deadtimes and incorrect cc's simply because I wasn't running the injectors at their rated pressure. Resetting the values in my injector tables would have done nothing. It was a dumb mistake by me