Hey. I have a stock 5.3 with the mp112 putting out about 6-8 psi boost. I am assuming the pulley is the 3.3 or 3.4. I would like to go a different size pulley and was wondering what would be a good size to go with? I have a 2.8 pulley, but was told that it was too much for this stock engine. So I would like to either sell it, or trade it for a 3.0 pulley. If 3.0 is going to suit my needs. Any thoughts.

 

How much boost do you want?

 

Just wanted to know what pulley to go for a stock 5.3. Would the 3.0 pulley and the extra boost harm the stock 5.3 in the long run. Would I be able to run boost pressure's of say close to 10 psi and still have a reliable engine. I have long tube headers installed and have a black bear tune.

 

I have the 2.9 and running just at 10psi. 2.85 wont hurt the engine as long as you have the proper tune. Also belt slippage can be a problem when you put on a smaller pulley. An HD tensioner should be purchased if you go for a smaller pulley.

 

If you have the fuel system ( injectors and pump) to support it, 10 psi is no problem on a stock engine.

Remember your foot controls the boost, its nice to have it when ya want it.

Also like said, i would def. get an HD tensioner aand twin dayco 101mm idler pulleys to help with belt wrap.

Tell us your exact setup right now, cam? Headers? exhaust? current fuel system??

 

I have a 5.3 with Katech rod bolts. I ran a 2.6 pulley at the end of the year, and next spring I am installing a 10% over drive crank pulley. I wouldn't worry about a 2.8 at all.

 

Thanks for all the reply's. The engine is bone stock. I have a high flow in tank fuel pump. The injector's are 42 lb. The gear ratio is 3.73. I have the hd shift kit in the stock tranny. I did mention that I have LT headers, and the pcm is black bear tuned. The intake has a AEM dry filter. I run premium unleaded fuel. My main goal was to run higher boost that would not hurt the longevity of the engine. If I can run this 2.8 pulley and not harm the engine, then that's what I will do. I just wanted to see what opinions you guys have and what would be the best pulley to use for my application.

 

Your tune will need to be spot-on perfect for you to run that small pulley. Do you know how much timing you're running? Are you monitering your AFR's?

You never said anything about your cam, just that your engine is stock. If you're still on the stock cam, and wanting a big performance gain, that should be your next mod. Not the small pulley. Just my opinion.

 

If you dont have a wideband already, invest in one and watch it when you press that skinny pedal. More air = more fuel

I highly recommend the upgraded HD tensioner. I havent pinned my crank yet but will def be on my next to do list and would suggest it to you if you haven't done so yet. A list of your other supporting mods would be helpful as well...

 

You'll need 60lb injectors as the 42lb will be maxed out