Boosted lt1, high compression and timing

[Fast4.7]

I did some digging and the knock sensor stuff is odd.

02 Express 5.0 uses KS2
97 LT1 (mine) KS2
02 Express 5.7 KS7

I compared the 02 5.0 (KS2) to the 02 5.7 (KS7) with efi live. Efi has sensor sensitivity settings as well. Either way both tuned were EXACTLY the same for knock sensitivity settings . So its possible to say the KS2/KS7 sensors should interchange.

O well. Its been a while. I haven't had a chance to get out. I'm going to try 16 degrees and work from there.

My 1983 G20 305 Q-Jet w/ ESC used a KS2. When I put a 350 in that van I put a KS7 in it. We used to do the same thing on 305 to 350 TBI swaps.

[anniversaryss]

My 1983 G20 305 Q-Jet w/ ESC used a KS2. When I put a 350 in that van I put a KS7 in it. We used to do the same thing on 305 to 350 TBI swaps.

You're saying they are interchangeable?

[anniversaryss]

Have you actually seen the knock sensors report anything? I still haven't had a eficonnection or torquehead swap report any knock at all.

I've seen up to 5 degrees in the lower rpms before 24-3600rpm but I think it was false knock tho.

I've never seen any knock up top at wot but I think 33 degrees NA was fairly low even with TFS heads.

[Fast4.7]

You're saying they are interchangeable?

Electronically they are, frequency they are not. The KS2 is usually used on a smaller 3.735" bore. In TBI conversions or 350 swaps the KS7 is usually used on a 4" bore.

[anniversaryss]

Electronically they are, frequency they are not. The KS2 is usually used on a smaller 3.735" bore. In TBI conversions or 350 swaps the KS7 is usually used on a 4" bore.

Ah so it would be beneficial to swap to a ks7 then?
Its kinda odd tho that my lt1 is a 4" bore iirc and uses the KS2

The least I could do is buy a KS7 and chnage it and see what happens

[DrLoch]

Is there a GM part number for the KS7 or are you just buying based on the "KS7"

[anniversaryss]

I just go by KS7 which is standard motors

I believe the GM is 10456288

Acdelco I believe is 213-324

[anniversaryss]

The 5.0 l30 has a different part number than the 5.7 l31

[DrLoch]

Thanks, just wanted to clarify. I got (2) 10456288/213-324. In the process of going through my engine again and will be replacing the ones I was using.

[anniversaryss]

Yeah according to GM parts direct and advance auto those are the correct part numbers for the 2002 Express 5.7.

The ks7 is like 30 bucks the ac delco is 60

[anniversaryss]

I installed the KS7 today. Going to get some seat time in soon

[anniversaryss]

I'm up to 18 degrees and I'm at 14.5-15 psi. A little more than expected.
I havent seen any real knock event yet. Tuning on 93 at the moment and e85 sooner or later.

Also using the KS7 or Express van sensor

[DrLoch]

Thanks for the update

[Ben Charles]

I'm up to 18 degrees and I'm at 14.5-15 psi. A little more than expected.
I havent seen any real knock event yet. Tuning on 93 at the moment and e85 sooner or later.

Also using the KS7 or Express van sensor

You’re a ways off on timing still, mid 20s be the sweet spot on 93 with that combo

Oops sorry at 11.1 CR you’re fairly close to being maxed on 93 octane, I had Lower CR in mind..

[anniversaryss]

You’re a ways off on timing still, mid 20s be the sweet spot on 93 with that combo

Oops sorry at 11.1 CR you’re fairly close to being maxed on 93 octane, I had Lower CR in mind..

Thank you Ben. Yes I'm working in it slowly for now. As you said I feel like I'm pretty close to being set with timing until I run E85.

I'll keep updating as I go. Once a week is slow moving lol

[Alvin]

A dyno would really help for that. I wouldn't trust that the knock sensors define the limit. I'm still not sold on 411 swapped LT1's and normally functioning knock sensors.

Seems like all of them miss picking up real knock.

[anniversaryss]

Yeah I'll get back on the dyno sooner or later I'm enjoying street tuning for now. I prob wont up the timing anymore until I get on the dyno

[JnJSpdShop]

Yeah I'll get back on the dyno sooner or later I'm enjoying street tuning for now. I prob wont up the timing anymore until I get on the dyno

If you aren't using my dyno or Alex's loaded hubs on Grand Island just do your tuning on the street or track. Inertia dynos are only good for measuring horsepower & torque, they are useless for tuning fuel/spark (finding MBT)