I need to change my accessory belt on my stock 99L. I was looking to get a LFP quickchange kit for my truck to swap out the stock caged unit.

I thought I read a post once that you can add a 2# pulley to a stock tune. Is this true? Will it damage my engine if I run a larger pulley?

 

It can be a problem in the winter air, the risk is that the maf can't keep up with the increased dense air as a result the gas to air ratio gets lean. I have run a 2 # upper in the summer to offset the warmer and thiner air. But I taook it off for the winter. I hoiw ever was also running other mods with a dyno tune.

If you are going to the trouble to install a bigger pully why not get e tuner and get more timming.

 

I haven't had my lightning that long but I do know this basic rule from the turbo cars and previous supercharged vehicles I have owned. A "GOOD" tune from a "GOOD" tuner will do more for your vehicle than adding parts and not tuning. Not only will it free up what the factory left out it will have a your truck running on a tune personalized for it instead of the same one that all other trucks run with from the factory. I would get a tune first or at the same time you add any parts to your truck. Boosted vehicles can spike the MAF bad enough to blow the bottom end with only a few days on an incorrect tune or of running without tuning the vehicle for the parts you put on.

 

im not really looking at getting maximum power out of my truck by doing all sorts of add on parts and tuning, I really dont have the $400 for a tune. My accessory belt needs to be changed, and because the stock caged pulley that is on it now is such a pain in the *** to change I figured it would make sense to just get the LFP kit that comes with everything to swap out the old pulley. I just wasnt sure if the extra 2# (closest to stock pulley available) would mess up my engine.

 

Now; from the little I know, the factory tune is nice and fat, it will accommodate high and low attitudes and can handle extremely hot temperatures as well as extremely cold temps. (Yes sir, this is the way it comes right out of the factory)!!!! For that reason alone I did not trust any tuner….

Now from the little facts that I have read, and mind you once more it’s only my opinion (which carries very little weight)! A purchased tune is only as good as that one tuner, if you Dyno tune it’s a little better! However; that tune is only good for Hot weather, and you need another tune or program to run in Cold weather… If you got your tune in “lets say in Colorado 6,500 feet above sea level”, that tune regardless of the temperature” will not work at Surfside Texas @ 4 feet above sea level.

So a Purchased tune is very narrow and sensitive to everything, it also depends what conditions existed when they wrote the tune, let say 80 degrees F with 60% of humidity, I guarantee you that the vehicle will act differently (such as horsepower and torque) @ 100 degrees F with 90 Humidity!! Where a standard factory tune is very wide and will adapt or adjust to extreme conditions!

So I say go for it, get rid of the caged pulley, it sure makes it easer to change the accessory belt, (that is a given)! A two pound pulley will give you something that you will feel, but I decided to go to a 4lbs…

Now what happened to me after 40K of running 4lbs with the stock plugs and the stock tune, one cold morning (about 5:00 AM) on a long WOT ( playing with a Firebird/Thunderbird You know the one with a pigeon painted on the hood ) I burnt two plugs. After that I got a tune, change my plugs, and made 450 hp and 500 some lbs torque, now before the tune I did not had that!!

However; once more, now I have over 120K and running +6lbs with a tune, and during that time I have burnt plugs on two occasions…. Is it the tune or just the conditions where not just right for everything to work together…
Heck don’t know, But I did burnt the plugs…….

I say go for it, add the two pounder and forget it, you will be fine…

 

they sell stock size rings... but if you don't have money for a tune then you probably don't have the money for a pulley and belt....

 

hhmmm.. $200 for pulley vs. $600 for tune+pulley. no where did i say im doing this to get maximum performance out of my engine. my truck is completly stock and that is the way i like it. I just thought that seeing changing the stock pulley and belts are such a pain in the *** why not put a non caged on it! Thats why im not justifying the extra $400 for a tune.

 

Adding the 2lb pulley won't cause you any problems (the stock PCM is more than capable of compensating for it) and it will give you a little more power a little quicker. I had one on my 01L back in 01 and made no other alterations while running it and had no problems.

Later on, if you decide, you can always do more mods.

 

I think you are safe running a 2# with no tune. Of course a factory belt is cheaper than a pulley and belt, lol Just kidding good luck let me know what kind of results you see from the ol' butt dyno if you will

 

I know this is a month later, but I would say to spend the extra to get a good programmer and have a good tuner do it on a dyno evem without the #2 pulley. You will be surprised at what can be extracted both hp & mileage just from correcting the factory parameters for your location. Like had been said earlier. The factory is set to accomodate a wide variety of scenarios. Plus, the programmer is now yours and if you did decide to mod more later, you already have that covered. Just my 2 cents. I hope everything came out for you.