Too much knock

[tsidrift1]

Well guys, I turned the boost up to 15 a few weeks ago. I was messing around with the car this weekend a little bit. I have noticed in third as I am on it, it seems to make one large backfire. I figured it was probably just a boost leak or something. I went and logged it this morning and I noticed that my knock count is way up again high 20's at times. I have weiseco 8.5:1 pistons in the car and I know I was going to have to deal with knock a little more now, but at 15lbs already. my mods are in my profile. I dont know why I would be getting knock so soon. I turned it down to 10-11lbs. and everything is fine now, well, I had 1 coubnt of knock. What can I do to run 15lbs safely.


Let me know,
Anthony

 

[Black_Bullet]

I can tell you what the problem is right now.... Given that you have fmic you must know its not the boost temp, especially considering that your probably still running stock rich fuel maps... Its your timing maps...
Your a 1g, and if your running stock 1g timing maps with 2g pistons you will get knock at anything over 13psi because the 1g maps are way too aggressive in their spikes and peaks.
Ive delt with this issue before a long time ago with my old gst when i put 2g pistons in it. The only solution now is to either get a thicker head gasket to bring compression down some, which doesnt help much, or get something to really tune with such as dsmlink or keydiver chips and with that convert over to the 2g timing maps... Whatever you do, dont get a safc because that will further raise timing adv with bigger inj and make it even WORSE. Looks like your going to have to get dsmlink sooner than you thought. ..( saw it on ya parts wish list.)

(( p.s. Sexy looking talon you have.. ))

 

[tsidrift1]

hey thanks a lot. Yeah I will just keep it at were its at then for boost. it felt fine at 15 lbs but I just noticed it was knocking like crazy. Ill play it safe and keep it were its at then.

What about a translator. I have one that has been sitting around in my garage now for about a month. I read that they are not very good to use just by themselves, so I was going to wait till I get link to mess with it.

Thanks,
Anthony

 

[Black_Bullet]

Nah go link... Do you already have a eprom?

 

[tsidrift1]

yes, I have just ben waiting to get some extra cash to get link. I am also getting a dual bb pte 5031, afpr, 255, 680's,tial external gate and some other goodies this winter. I just have to wait for tax return time.

Anthony

 

[oldman]

I can tell you what the problem is right now.... Given that you have fmic you must know its not the boost temp, especially considering that your probably still running stock rich fuel maps... Its your timing maps...
Your a 1g, and if your running stock 1g timing maps with 2g pistons you will get knock at anything over 13psi because the 1g maps are way too aggressive in their spikes and peaks.
Ive delt with this issue before a long time ago with my old gst when i put 2g pistons in it. The only solution now is to either get a thicker head gasket to bring compression down some, which doesnt help much, or get something to really tune with such as dsmlink or keydiver chips and with that convert over to the 2g timing maps... Whatever you do, dont get a safc because that will further raise timing adv with bigger inj and make it even WORSE. Looks like your going to have to get dsmlink sooner than you thought. ..( saw it on ya parts wish list.)

(( p.s. Sexy looking talon you have.. ))

That is too broad of a statement to make at this point, timing is only one factor, you can also get knock from running too rich, bad gas, high intake temp.....etc. I'm running 9:1 compression at 24 psi with straight 93, besides the usual 1G 6k timing spike, I have made very little timing adjustment (aside from adding 1-3 degrees between 6.5-8k) to the timing table and I have no knock to 8.5k.

 

[tsidrift1]

That is too broad of a statement to make at this point, timing is only one factor, you can also get knock from running too rich, bad gas, high intake temp.....etc. I'm running 9:1 compression at 24 psi with straight 93, besides the usual 1G 6k timing spike, I have made very little timing adjustment (aside from adding 1-3 degrees between 6.5-8k) to the timing table and I have no knock to 8.5k.

What do you suggest I start to look at?



Anthony

 

[2gGSX]

Without seeing a log, I would say

-Boost leak
-Base timing
-Fuel pressure
-Metering

 

[oldman]

Without seeing a log, I would say

-Boost leak
-Base timing
-Fuel pressure
-Metering

Sounds good to me, then again, boost leak test always sound good to me.

 

[tsidrift1]

Its probably been a month since a boost leak test, but when I tested it last, I hit 20lbs with no leaks, except for the tb shaft seals. I have no way of checking my fuel pressure. As for timing, is there a different setting I need to be at to run the higher compression pistons?


Anthony

 

[2gGSX]

No, it is to ensure that you are at 5 degrees BTDC base timing. If it is advanced at all, on top of your already aggressive 1g timing map, then you can bet that is a big contributor to your knock.

 

[tsidrift1]

well, I will get my timing gun back from my friend and check the timing again on it when I get some time.



Anthony

 

[Black_Bullet]

That is too broad of a statement to make at this point, timing is only one factor, you can also get knock from running too rich, bad gas, high intake temp.....etc. I'm running 9:1 compression at 24 psi with straight 93, besides the usual 1G 6k timing spike, I have made very little timing adjustment (aside from adding 1-3 degrees between 6.5-8k) to the timing table and I have no knock to 8.5k.

Perhaps, but I was referring to one of my past experiences because it sounded so similar of a situation with the 1g ignition timing and 8.5 + compression ratio combo. I bet im on the right track, but yes mechanical timing advance being off, boost leaks, and etc will also increase chance of detonation which those will always be first steps to solving the issue, and i assumed he wasnt stupidly running 87 octane, so unless he's got bad injectors or fuel pump and is leaning out real bad high 20 counts of knock is excessive and
most ppl dont knock at under 15psi especially with fmics and hes running stock fuel maps so thats why my assumption was accurate to me. To the OP if youve done everything you can to figure out the problem and it still gets more than 10 counts of actual knock; refer to my first post in this thread....