Drive(Serpentine Belt) problem...

[TISon28s]

Ok, so i have the unorthodox lightweight crank pulley. Just a couple of days ago, my drive belt started making noise. I look under the hood and it looks like belt residue is around the inside of the crank pulley. could this be because the belt isn't tight enough? What type of belt can hold thepower from my motor? I have about 340 at the crank on my 04 sedan. thanks!!

[tollboothwilley]

how long has it been since you changed your belts?

The only time I have seen a belt get "eaten" was when a pulley was losing its bearings. Check your other pulleys. One of them could be going out.

[joe603]

Sounds like it needs to be tightened. I think 1" of play is the correct tightness.

As for your HP numbers...I really don't think that you're up there (with your list of mods) without FI on our engines. If I had to guess, I'd say you're around 270-280.

See this thread for model/year HP/TQ ratings: http://forums.g35club.org/zerothread/327050

[Sentientbydesign]

As for your HP numbers...I really don't think that you're up there (with your list of mods) without FI on our engines. If I had to guess, I'd say you're around 270-280.

See this thread for model/year HP/TQ ratings: http://forums.g35club.org/zerothread/327050

I didn't read his mod list and thought he had a low PSI blower.

TISon28s,

Even if we use some oddball math I can't see you pushing 340 to the crank. Sorry if that bursts your bubble.

04 sedans were rated at 260 peak crank hp. If we say they mistated it, then let's go with the 280 from the coupes.

280 + your mods may tip you over 300 to the crank, but that's questionable.

Here's a good link for comparison:

http://www.gurgen.com/clint/G3....html

Look at THX723 (Clint). His mod list is pretty similar to yours. Actually, slightly more involved than yours. He has an 04 6mt on a dyna pack putting down 281.5 (this type of dyno mounts to the rear hubs, not wheels, so it's much closer to crank power, than a dynojet.).

[SteveTheTech]

Ok, so i have the unorthodox lightweight crank pulley.

You answered your own question. You need to get a shorter belt. Measure the belt and get one an inch or two shorter. Clean the burned rubber off the crank pulley, and tighten the new belt to ~1/2" deflection.

What type of belt can hold thepower from my motor? I have about 340 at the crank on my 04 sedan.

No Way, sorry to call shenanigans on you but not possible with your mods.

[Sentientbydesign]

Steve,

Your suggestion only applies to the underdrive pulley, right? I would think the stock diameter lightweight pulley would use the factory belt. Am I missing something?

Just want to know because this is on my "long list" of mods.

[SteveTheTech]

I really do not like underdrive pulleys and I think they are not usefull, but that is a side issue/ I have little experience with these as mods. I really do not know how much smaller they are, but it seems more than likely that if there is no more adjustment in the tensioners a smaller belt would be needed.

Now I am going to have to look into this.

[Sentientbydesign]

Unorthodox racing generally has two lines of pulleys. Both lines are CNC machined T6061 (I think). One of them is an underdrive setup with a smaller diameter crank pulley. I'm almost positive they require smaller belts for this.

The other is a stock diameter pulley/pulleys. These are used for weight loss and as the set weighs 4.5lbs less than stock. I can't speak for actual gains.

[SteveTheTech]

Yeah I know I have read their website too.

If you have ever looked at a crank pulley you will notice that there is a rubber band between the two sections. This acts as an vibration mechanism under some driving conditions where harmonic resonance may transfer.

The cost/benefit ratio doesn't work for me on ud pulleys, is it more about the weight? Really is weight that much of an issue with a G? The car is a brick, a very nice looking brick but its what it is and 9lbs of mass will not have noticeable difference. lol.

I am not turning this into another fight with you Nate. The products may indeed be built extremely well, I have only seen one OE fail on a 3.5. Plus the installation is not usually a party, as the crank bolt can be a PITA.I will admit the look very cool and fast.

[Sentientbydesign]

I'm still on the fence about this mod, but I will say that I believe that the G has LOTS of weight that can be shed. Maybe I'll pick up that scale this weekend and start weighing things.

I know it's supposed to be a luxury GT, but I want more performance out of my luxury GT.

[SteveTheTech]

If you want more power go FI, superchargers produce the most power for the least amount of work and irreparable alteration to your G.I have seen people remove superchargers and most people would never even know they were there, decent job. For a turbo you will always find something that will not be right. They are a relatively easy install and the benefits are the lower boost under the right tuning should keep your stock block from blowing. This is the only serious mod I would even consider.

IMO you can sink thousands of dollars over a long period or save up and do it all at once and do it right. That is a different thread though. I guess that come with years of living with an accountant though, it's tainted my car guy needs.

[tollboothwilley]

That is the right way to do things....but many people don't want to trade the reliability issues of FI + the cost. Also, its an extensive mod that most aren't willing to do themselves. But we all WANT IT.

The idea behind the crank pulley is not so much to shed overall car weight but more to reduce rotational mass as less of a drag on the engine.

Underdrive...well...thats different too as you know.

[SteveTheTech]

Your POV is very understandable, I am very cheap myself and also very lazy with my own cars (I have never liked working on my own cars, too much like work). I may add an intake and maybe exhaust, but that would make the wife complain so probably not, I do however like to wish.

[tollboothwilley]

I've never done a SC or Turbo but its something I plan on doing on a car of mine. To be honest though, I am scared I'll forget something small and it'll blow the engine before I get a chance to run it.