After reading many difference conflicting viewpoints on timing numbers, I can't come to a conclusion on the subject. I know the majority of LS combos like 28-29* of timing max. Thats where the make about the most power safely... I keep seeing some people say that that rule applies to the 4.8 as well, while others say they like around 34-35* of timing at WOT... I have seen claims for both arguments but no real results to to back up either claim.

Opinions, arguments?

 

Get it on a dyno and find out what it likes. You can push the timing past peak hp and see no knock retard. So its just a matter of finding what your particular combo likes.

 

I run 27-29 depending on load on 87* swill. On the street it can get a little kr on down shifts but ehh its a 4.8 soooooo. I also knocked my decay rate down too. I pumped a **** load in at cruise and its made a huge differance on mpg.

 

I have the knock sensors desensitized according to the "Tuning the right way" pdf. Its a 4.8 with bolt ons, converter, 4.56's anda 226/229 cam and some BR6EF plugs. It pulls past 6800 rpm easy but its on a stock timing chain and owner is afraid to push past it. Don't have easy access to a dyno unfortunately. I do have the virtualdyno software and know it can be pretty useful for seeing gains/losses but not necessarily accurate at a real HP number. Haven't tried it out though.

Just trying to get some different opinions.

 

mines just a bolt-on 4.8 for now. Throwing my cam in the next few weeks. I had way less timing in it till i threw it on the dyno, as my afr was around 13.0 on my street tuning. Depending on the dynamic compression of that cam you may have to put more in at lower rpms the pull some at peak torque and put it back in up top.

Edit i also never "desensitize" My knock sesors i just allow timing to be put back in faster for * of kr I pull 1/2* of timing

 

Btw those are high comp, light no2 or e85 plugs... why you guys running those?

 

The 4.8s do like a lot of timing. Every setup is different but a cammed stalled 4.8 will typically like over 30* on 93 and stock compression.

 

it will see nitrous this spring

 

Stock compression on 4.8s is relatively low...so that's likely where you're getting your '4.8s like a lot of timing' information. As for there being a particular number that all combos like, I would forget about it... Every cam/heads/intake/power adder combo is going to change the MBT values. When someone tells you that LS 'combos' make the best power at 28 degrees of timing...you can just assume they haven't done their homework.

 

Nice... the non-projected tip plugs also tend to let a * or two more of timing on an na setup. Should be fun.