You need a heavier pulley to dampen the crank. The weight of the pulley is the issue, not the under or over drive.

About the HR cams and stuff. Iirc my best friend that's a master tech at BMW (that also has an infiniti dealership attached) there is a flatrate of 10 hours on cams on a g35. I asked him about it when i was tearing mine down so he looked it up. That's at least a grand in labor for someone who can't do it. Probably a little more in doing the springs on top of that.

exemption: With the difference in the heat in the plenums. Plenums don't really transfer much heat into the air since there is minimal surface area and the velocity of air traveling though it is so fast when WOT. The change in power i got from icing my plenum down to freezing with dry ice and doing a pull verses heat soaked wasn't even noticeable on the graph. Now something like the intercooler that has tons of surface area for the air molecules to contact then yes, the heat will transfer easily into the air. It will probably be a waste of your time to change them and see. Plus they are 2 different plenums so you are comparing air flows instead of straight heat. My "normal" verses "iced" plenum was more of a direct measure of the heat transfer and it proved almost nothing.

 

dont really need a heavier pulley just need a dampened one which the lightweight ones dont do. the dampening isnt associated with the weight its the elastometer that connects to the belt surface and the hub surface. it only works in a specific rev range however, the elastometer is specific to that engine and rev range. if extending it with cams and such there really is no way to beat a fluid type damper like the fluidamper

 

You could do the cam swap in car... But I agree it's a serious pita. Although for some reason a lot of vortech cars run stock block with cams... As you saw op already has cams. Weird I know but I just want to plug HR cams anywhere I can as an alternative... for most DE setups it's a step up and it's quite a bit cheaper than regular cams.

What? I've never heard of an elastometer... Either I'm missing something because I've been up for 24 hours, OR somethings a bit herpaderpa here.

 

when you pull the crank pully off of it it should have elastometer like a super hard rubber on the inside facing the engine, the thickness and hardness is determined by the stock power band and what frequencys need absorbed. ill admit i havnt had the stock pulley off yet but i have never seen a single production engine that dint have it.

thats why the liquid filled pulleys are so much better because liquid will absorb any frequency vs the elastometer will only vibrate and absorb specific frequencys

 

not sure if these are right as im having a hard time finding oem pulleys and this website has a pic of two different pulleys for the vq35 im going to assume one is for our cars and another for fwd vehicles but they could be the completely wrong pulley rofl gona have my wife take a pic and send it to me now =/
this one looks like the elastometer is bonding the hub to the actual pulley surface.


and this one looks like the smaller diameter pulley is mated to the larger with elastometer.


cant tell for sure or not i intend to use fluidamper so i can hack my stock one apart when i get back.

 

Hmmm interesting.
You mean this? It's a terrible picture, but the band is totally visible

 

ill have to check the pic out in the morning im sitting in the office in shorts and flip flops, cant sleep from having three days of guard in the middle of the night. work comps block out just about all photo sharing sites if you wanna email it to me at jerryd87@gmail.com i can look at it though

 

Thank you for all the pulley information you 2 much appreciated !

 

I've changed heads in my car. Dealers do the cam swap in car as well. It is a major PITA. Last time i did head gaskets i pulled the engine, changed the gaskets and installed in less time than leaving the engine in to do.

and yes, the stock pulley does have a sad attempt at dampening material. Based on it's makeup one would think the weight has to do some work to dampen the crank as well. Weight isn't the main factor but if it didn't do anything at all then someone would have made lightweight dampened pullies by now.

I use the ATI so i don't have to deal with any fluid. Both ATI and fluidampr do a great job though.

 

I defend my self on cam proposition via OP's already done it !

And that ring didn't even feel like it was rubber, if it was elastic at some point it's long lost all elasticity, and this one only has about 40k miles on it.
+1 on ati, I've got one... in pieces at the machine shop lol

 

Alot of the small block chevy aftermarket pulleys are several ounces lighter then stock and dampened, not sure why they dont make them for this platform as well since a v6 is naturally rougher then a v8. metal isnt very good at expending the energy, well the energy isnt really expended its simply transfered to the air, metal dosnt move much so not much is transfered. without anything the vibrations will travel to both ends of the crank, hit and then travel back inwards, some energy will be transferred but not very much and it will continue to grow every time a cylinder fires. That said a large amount of the vibrations on this engine are absorbed by the dual mass flywheel so there isnt alot required of the pulley but some is still required, heck even engines without dual mass flywheels dont require very much think the strip of it on my old 305 stock pulley was about 1/8th inch thick and 1/4 inch wide, not very much considering it used a single mass flywheel. the elastometer uses much more energy because it can move more, but it must be tuned to the engine too soft a material and it will fly apart at higher rpms or stretch and create harmonics of its own, too hard or too much and it wont dampen at lower rpms.

honestly going with lightweight pulleys with the oem flywheel probably isnt a big deal but going with a aftermarket single mass flywheel i would say ati or fluidamper is required even more then the stock piece.

 

errr actually ignore the begining of my last post i blanked for a moment the small block chevy has the dampener as a seperate piece from the pulley

 

ya, i think their "harmonic balancer" as they call it bolts onto the front of the crank pulley. I can't say all, but i've seen quite a few that just bolt on.....as i've also seen them come violently flying off at the track as well

 

its pressed on then has a really big bolt on the front then the pulley bolts onto the front of it with 3 10mm bolts. most tracks wont let you run past a certain et/mph unless you have a sfi rated one since they do tend to explode lol. most of the time its refered to as a harmonic balancer, hmmm 4.6 mustangs where the ones i was originally thinking of the pulley and balancer are one unit and you can get the steeda unit or aluminum ati to replace the factory steel one and save yourself about 4 or 5 oz.

honestly though that little bit of weight might make like 1 hp, most of the power comes from the underdrive.

it really dosnt take much though just something flexible usually rubber(although most of us would consider it hard plastic by how tough it is) so that vibrations can be absorbed and not eat the bearings away kinda makes me wonder how many people who had eaten up bearings where running stock or lightweight pulleys with single mass flywheels. hadnt considered it at first but it would definatly do the trick. either way im going with bigger clearances and a fluidamper lol. reminds me i needa go order some new micrometers and dial bore guage, sold mine when i joined the army and def dont trust the public stuff at the hobby shop...............

 

easy, tune ==>uprev ftw
spacer ==> blox 1/2 or any other upper plenum (aps,crawford) but not the kinetix

 

do you mean "easy to tune" or "easy to pay someone else to tune"

osiris is by far the hardest and most complex tuning software. of all i've used it's the hardest and a pain to use other software to get my a/f and compare.