my KR

[Warbeaver]

Question about KR...

Back in October when I had all my mods such as HV3, ER rockers, wizair, and dogbone mounts, I got absolutely 0* of KR in all gears/rpms using 93 octance. After the demod, I got like 6-7* of KR in 3rd gear. My buddy tuned it, and decreased my timing a bit along wth a new MAF tune. KR went down but i still get it. I am using 87 octane now and still getting 6-7* of KR. The tune i have was done with 87 octane. the KR does go down when i switch to 93 so i know its not false.

my question is, would having too cold off a plug cause knock? I am running ngk tr55 gapped at .060. I used to run autolites gapped at .058 but my buddy said i should run the biggest gap possible without getting spark blowout. I am not heavily modded so i dont see a need to decrease the gap....would that decrease KR if i did though? Would not enough incoming air cause knock? i no longer have the free breathing Hv3 or the wizair, but i do have a gutted stock airbox with a drop-in K&N.

Just some thoughts on what i could do.... mods now are tune, 180* t-stat, 3" DP, fuel rewire, wrapped manifolds/xover, gutted airbox w/K&N, and i think thats it as far as engine stuff.

[Bio248]

too cold of plugs is just going to cause bad gas mileage.

i would just run premium and call it a day.

[Warbeaver]

hmm, well i get about 28mpg highway and like a 25 mpg average with highway and city so i guess plugs are ok.

one reason for demod was to save money by running regular. I don't wanna go back to premium. gas is going up, up, up

it was just weird, with all those mods i was getting 0* kr and after i'm seein it at 6-7* constant at third gear.

[Bio248]

that's fine, you can save $2 per tank if you want. i put premium in my impreza...

[MrTube]

You said you did the mods in october. I've seen ambient temperature play a BIG roll in spark knock. If your pulling in 50F air your going to have a lot less chance of knocking then pulling in 80F air.


Also you ran 93 octane with the mods, no?

I've never run a scanner on a modern engine. But I wouldn't be surprised if a small amount of knock on regular gas was normal even stock.

[matt5112]

my GT knocked that much when stock.

It knocks up to 3 * with headers and a short ram intake on 94 octane with no tune.

[Warbeaver]

its not the ambient temps. i had those mods for almost a year before demodding in october. my engine temps were always low, and intake temps were always pretty much same as outside air. I did a pull last week when it was 40-* outside and it knocked like i mentioned.

ah well. i was wondering if i put an hv3 back in there if it would decrease my knock lol sounds dumb, but i got knock after taking the stuff out and it still does it regardless of tuning down the timing. I was running crazy high timing according to my buddy. but i could, cuz i had no knock lol

[matt5112]

flow mods get rid of knock. not much else to it.

I hate my car for knocking with no boost and headers but theres nothing I can do about it really.

[GeosGP]

Seems like these cars just do that. But without a wideband, I can't tell if it's real knock or not.

Also, they oxygenate fuel during the winter, no?

[blueguy]

Isn't your car tuned? Tuned cars require the higher octane to prevent the knock...there ya go.

[GeosGP]

Isn't your car tuned? Tuned cars require the higher octane to prevent the knock...there ya go.

Unless you brought your timing back down...

[Warbeaver]

yes it is tuned, and i know u usually have to run higher octane gas, but i thought that was mostly cuz of the timing

thing is, i dont know what stock timng is. I think at a point i was running like 32* of timng....buddy said he lowered it 6* which would lower about 3* of KR. Timing i remember now is like 26* but i guess i need to look again during a WOT pull sometime.

[matt5112]

22* is stock. thats all you should need.

[Warbeaver]

well that could be the problem. im running 26*+ instead of 22* with 87 octane.....

[matt5112]

yup.

[MrTube]

stock timing is 22 degrees at what rpm? idling? I would think 22 degrees idling would be kinda rough.

If i'm remembering right. fuel takes approx 2ms to burn under most conditions and a crank turns 6 deg in 1 ms. so you would want 12 degrees of advance at 1000rpm. If this math is correct it means you would want 72 degrees of advance at 6,000rpm in a perfect world.


eh?

[matt5112]

22* at WOT.

[Warbeaver]

well thats about right. a 4 degree difference would be 8* of knock which is almost what im getting. its around 6-7 and thats with lower intake/engine temps and a 3" DP

[MrTube]

22 deg at wot at what RPM?

[matt5112]

when going WOT it locks in and stays that way... At least mine does last i checked.