[KingLT1]

It's been tested and proven that 160 degree coolant temp does not make more power then 180. LT/LS engines actually like some heat in them for optimal combustion. Supercharged cars run cooler T stats to help with the additional heat created by the Supercharger its self. On a NA application there is no point to run it any cooler then 185-190.

[cmitchell17]

I will say since I've fixed my thermostat, I now notice a lot more knock retard being pulled at WOT. I run E85 (more like E74) 100% of the time so I was surprised.

If you let the coolant get too hot, it will knock enough for you to audibly hear it. My stock oil cooler hose busted and my coolant and oil temps got above 240 and I was trying to limp it home and even then it was knocking like crazy, I should've had it towed.

[lt4camaro]

Originally Posted by cmitchell17

I will say since I've fixed my thermostat, I now notice a lot more knock retard being pulled at WOT. I run E85 (more like E74) 100% of the time so I was surprised.

If you let the coolant get too hot, it will knock enough for you to audibly hear it. My stock oil cooler hose busted and my coolant and oil temps got above 240 and I was trying to limp it home and even then it was knocking like crazy, I should've had it towed.

And timing being pulled is a power loss. Run a 180 stat for the best of both worlds and you should have less or no spark retard and maintaining power levels versus losing power. Hot engines require more octane.

[s346k]

Originally Posted by cmitchell17

I will say since I've fixed my thermostat, I now notice a lot more knock retard being pulled at WOT. I run E85 (more like E74) 100% of the time so I was surprised.

If you let the coolant get too hot, it will knock enough for you to audibly hear it. My stock oil cooler hose busted and my coolant and oil temps got above 240 and I was trying to limp it home and even then it was knocking like crazy, I should've had it towed.

how much timing do you have in it?

[BlackbeastSS2]

I will be running a cooler thermostat with my cam/heads/headers package in order to activate the coolant system sooner and set the fans to come on earlier. Every little trick helps.

[cmitchell17]

Originally Posted by s346k

how much timing do you have in it?

About 27-28 degrees at WOT. The log I took tonight actually had basically 0 knock retard, except for .01-.02 degrees being pulled for about 500 rpms.

I think the knock that happened after I fixed the thermostat wasn't really do to the stock head temperatures, sometimes you just get random knock that can't be explained.

[s346k]

Originally Posted by cmitchell17

About 27-28 degrees at WOT. The log I took tonight actually had basically 0 knock retard, except for .01-.02 degrees being pulled for about 500 rpms.

on ethanol?

[KingLT1]

Originally Posted by lt4camaro

And timing being pulled is a power loss. Run a 180 stat for the best of both worlds and you should have less or no spark retard and maintaining power levels versus losing power. Hot engines require more octane.

He is running E74 which is about 105-106 octane. It shouldn't be knocking at stock compression or even with it raised. I ran 28 degrees timing on the same Ethanol content when I was NA bolt-on and never seen knock with the stock T stat. Yes the OP has heads/cam, but I don't believe the compression was increased so the dynamic compression is probably lower with the cam...and that should make it less detonation prone.

[s346k]

i have the same experience as king. i sat in my bolt on e85 car for 15 minutes letting it idle on a hot and humid day. iats were 115+, coolant temp hovering around 200. stock tstat & 27*. went from idle to a 1-4 pull and it had 0 knock. e75 ish.

i don't know that i've ever seen the car knock on ethanol. it had a touch more timing in it (28-28.5) with the stock intake manifold, tb & air box, but same results.