i want to get an upper pulley will it be safe to put on? i have a lower 4# with filter reflash and 90mm mass air. i have stock internals other than denso.what do you guys think?

 

you'll be fine, but IMHO i'd just get a bigger lower.

you might need a reflash

 

sell the 4 and get a 6#. would it still be safe? do you get more out of a 6 rather than a 4 2 combo

 

Do you get more? In a way yes, because the 4lb lower and 2lb upper will slip because of the smaller upper pulley. With just the 6lb lower, there is less of a chance of belt slippage.

-Mike

 

Swapping 4 to 6 is adding 2 lbs of boost. The only difference is that you will increase your belt contact area with a larger lower, and decrease it with a smaller upper. Pulley ratios are linear, so there's no difference in the boost/rpm map. The only downside to a larger lower is the slightly increased rotating mass, but on an engine producing 500+ lb/ft of torque at the crank, that is insignificant.

The change from 4#-6# is not as significant at the dragstrip as you'd think. At this level of overdrive, the Eaton is starting to produce more heat above 4500 rpm than the stock intercooler can keep up with. One blast down the strip takes longer to recover from, and some have actually lost power in hot climates without some significant cooldowns. However, on the street, you get improved SOTP feel because of the torque increase at lower rpms.

Having said all this let me clarify my statement before someone flames away: You will have increased HP and torque; however, the heat/boost level is reaching the point of diminishing returns.

As far as a reflash, only your tuner could truly answer that. However, reflashes are more tolerant than chips in adapting to changes (within reason). A 2lb increase in boost won't matter much unless you were tuned fairly aggressively before. Having your A/F ratio checked would be the reasonable thing to do.

 

thanks guys for the info using my judgement im gonna go with the upper pulley it will probably creat less heat and still give me at least 10-18 hp. now any suggetstions on a good pulley to go with the psp 4#

 

I would guess its a 99 or 00, dont bother with the upper, a 6# lower would be fine. I went from 5# lower and 1# upper to a 8# lower with stock upper. I did notice a big difference, but after driving it for a while I noticed a loss of power due to the heat. Bigger pullies are great for the 1/4 with good cool downs. But for a daily driver I wouldnt recomend it.