so if you get it with the alt also, then does that put your alt output back closer to stock?

 

That is what I thought to but dont know. My kit came with a alt pulley but have not put them on.

 

If the alt pulley is bigger than stock it will help with charging. If the pulley is smaller, then it's more underdriven and you'll have an issue.

 

pulley I got for my alt is bigger than what is on there now so I should be good and not have any issues right.
How do you like the underdrive what did it do for you.

 

good $100 investment in the power vs. price ratio. I believe the more mods you do to produce power in the engine, the more of that power gets transferred to the wheels instead of the accessories.

 

wait an minute, I think I got that backward on the earlier post, you need to think of it like bike gears. a smaller pulley will spin more times and thus work the alternator harder and produce more voltage. A big pulley turns the alt less and produces less. I think that's right.

 

I dont know what way it is but hope I dont have any issues
Also what about those heads you put on were they a good investment. I am thinking about putting them on my truck.

 

haha i have never seen or heard of one of those before. I am kinda new at some of this stuff. so what are the benefits of it again?

 

underdrive pulleys will be smaller on the drive pulley (crank) and larger on the driven pulleys (alt, wp, psp, a/c, etc). if you are concerned about lack of charging due to the too much underdrive, then a bigger pulley on the alt will only make things worse.

 

Basically, it takes some of the energy used by the engine to turn the accessory belt, and puts it back to the wheels by running all of the accessories: Water pump, Alternator, Air Conditioner, and Power Steering slower at the same RPMs as the old pulley, less power to the accessories=more power to the wheels at a given RPM.

Pros - Performance increase across the whole powerband, all the time, whenever you drive. Slight MPG boost if you can keep your foot out of it as you're using the same amount of gas but putting more power to the wheels to move the truck.

Cons - I'll list them one by one and why I'm not concerned with them, but why others might.

Alternator will charge lower at idle. It picks right back up when you start driving. If you're running electric fans, A/C, a big stereo amp, and lights this could be an issue for you at idle because you'll start to draw off the battery and that's bad if you're stuck in heavy traffic and can't get up to speed. You can buy pulleys for the alt that will increase charging, but you don't get quite as much out of the underdrive crank pulley that way. I just emailed Hemifever and he said he could raise my idle through SCT tuning so I'll get back to a decent charge. I'll lose a little in town MPG's from the increased idle, but I probably will net zero MPG change with the pulley gain. I loves me some SCT!

Water pump goes slower. This could be an issue if you tend to overheat. The water will be pushed thru the system slower and the clutch fan will spin a bit slower. I think opening the t-stat earlier (running a 180* stat instead of the stock 195*) could help offset that and making sure your cooling system is working correctly and the radiator is clean should be fine. I'll be watching carefully this summer to see if it's an issue. I have a feeling that it will even out as the coolant will spend more time in the radiator to cool as well as spending more time in the engine extracting heat. A high volume WP would probably make it a mute point if you're needing to replace it. The only way I would say no way is if I was working in and extreme heat location or running 4-6RPM's for long periods of time.

Powersteering pump operates slower. It might work the PS system harder, but I sure haven't noticed ANY issues as I hardly move my wheel while not moving. the hydraulic pressure is fine, not sure if overheating the PS pump would be an issue, but it's got a small cooler on it anyway. Might be a concern for somebody that wheels a lot at slow speeds or somebody that drives in circles or figure 8's all the time.

A/C runs slower. Might take a little longer to cool down the truck, my e-fans put cooler air thru the condenser so it's a non-issue for me. It might also help the A/C clutch and compressor last longer though.

ASP claims at least 6hp gain and 26ft/lbs. that's on a stock engine and thats a pretty good $$$ to hp ratio since it cost me $100 with the pulley and belt. I believe the actual gain is based on a percentage, so the more power you are producing, the more it benefits you.