I have a quick question that I couldn't find an answer for using the "search button". I have the stage 2 kit installed with 42# injectors and 3.0 pulley. It has been fine tuned in, not a canned tune. If I dropped to a 2.9 pulley, would I have to retune? Or only if I go with bigger injectors? Any help appreciated.

 

Dropping to a 2.9 from a 3.0 is not a "huge" difference. You will gain a little torque.

Optimally you would tune for any airflow change, but you should be fine. Keep an eye on your afr.

The 42's can handle more than the kiddies on here will regurgitate to ya.

 

Appreciate the response.

 

I might as well ask here. MT2 Stage Kit Pulley Tool MT2

Is the GMS2 tool the only way to undo the blue bolts?

 

Yes.

 

^^ yup! only way.

 

2.9 will be fine. You shouldn't have to do any airflow tuning, or at least minimal if any. Depending on how aggressive the timing is you *MIGHT* have to pull timing back a bit. Some cars are more touchy when you make airflow changes than others.

I ran a 2.9 on my LSJ for the entire life I owned it and never had issues. The injector duty cycle with a 2.9 and GM 42# injectors is on the high side but still within the "safe" range, albeit just barely.

Oh, almost forgot, yes you have to have the tool for the GM blue bolts. When I had the Stage 2 kit installed on my car I made sure they gave me back the tool and the old injectors. They conveniently "forgot" at first and I had to remind them, but I did get it back. I swapped my GM blue bolts out for hex bolts as soon as I got my 2.9 so I didn't have to deal with the pain in the ass GM bolts.

 

Look at my signature.... You will want to drop the heat range on your plugs with a 2.9" pulley, trust me....

 

$23.52 for a bit? wow