Rochester

iTrader: (9)

OP, the 1 to 2 whp recovered (not gained) with a lightweight or under-drive crank pulley is a negligible thing in a high-HP, heavy car. The only thing noticeable with that mod are bragging rights. I had a lightweight crank pulley from Unorthodox Racing in my last car, and while it's a very real WTF moment when you're holding both the OEM pulley and the lightweight pulley in your hands at the same time, in the end it's just not worth the time and money. (IMO... always IMO.)

Instead of chasing HP, have you considered taller gears in the rear diff?

Only4theGnme

For me, and IMO...the difference from the underdrive pulley was noticed immediately in "pick-up", I think that can be described as torque gains, but I never had a dyno done to quote specs...my aftermarket underdrive pulley is also much lighter than the factory pulley so I don't know how you can hold them in your hands and not notice the difference because there was most def a difference noticed comparing the two in my hands and again after the install. I can't say I gained numbers in HP, but I'm pretty sure I gained torque.

IMO...it was worth it....but to each his own.

Rochester

iTrader: (9)

Re-read, because you completely misinterpreted. And I'm not sure how, because the difference in weight is so obvious. Hence the WTF moment.

And you might very well notice your engine rev up quicker when goosing the throttle in neutral, but there is no way at all you'd notice gains from a UDP when under load. It's just not possible. Like I said... hundreds of dollars worth of bragging rights.

That said, when done right, every incremental power mod is cumulative... although rarely aggregated. So you got that going for you, I suppose.

bluedevils95

iTrader: (2)

The 1st gen free up 15 and i would love to see what the 2nd Gen does to this. A before and after dyno would be awesome to see. But i don't want to pay $1400 for that CF Drive Shaft.

tejasg37x

All this talk about lightweight and under drive pulleys...

I used to disconnect my belts for the AC and power steering on my Camaro when racing it...of course that was 1/4 mile drag racing, but THAT did make a difference.
Of course you wouldn't want to do that driving on the street...but you could always do that on te Dyno just to get the numbers up.

Rochester

iTrader: (9)

^^^
When I was a kid, I used to have a cut-off switch on my alternator wired through to my dashboard (Pontiac Trans Am), so the belt would spin w/o resistance. Did it matter? Probably not... but it was a hobby.

On topic here, but I made what I thought was a reasonable suggestion to the OP about the gears in his rear diff. Yes? No?

tejasg37x

Very much so...gearing is the biggest bang for your buck.

It was quite fun in my Camaro after installing a built 350 ci, manual shift reverse pattern TH350 with very low first gear, and some 4.56 gears in the rear. Didn't bother with disconnecting the belts for the AC and power steering after that.

soolman32

iTrader: (15)

don't know if this has been suggested before but why not go with a nitrous setup? Not as expensive as SC or TT but if you keep it at 100 or less shot, it seems fairly reliable or so i've read lol

Rochester

iTrader: (9)

That's what I thought too, tejasg37x. And I've got my terminology upside-down. (oops)

Taller = lower ratio
Shorter = higher ratio

The 4.083 gears for the RWD G is off one of Nissan's trucks, I believe. And runs about $500 with a relatively simple install (for a mechanic).

I've only been doing casual research into it every now and then, however. It's on my list for far-in-the-future mods.

Can'tGme

iTrader: (1)

I was waiting on someone to suggest the 4.08 gears, lol. Yes the gears come off the Nissan Frontier truck. I installed them myself in my old 03 Z. I literally gave the dealer a random VIN number from a 06 Frontier I found on AutoTrader and had them order me the ring and pinion, crush sleeve and seal for it. I installed it at home in my garage on jackstands and had ZERO issues with it. It was by far the BEST mod I had ever done to that car. All for around $500.

To the OP: If you really want to make a huge difference in acceleration for cheap then I highly recommend putting in the 4.08 gears.

A little tid bit of info though; I did not have to shim anything inside the rear diff when swapping the gears. I was very lucky that it all lined up perfectly. Be aware that it can get tricky if you have to shim it up. If everything is not lined up where it's suppose to be then you will bust the gears the first time you take off. I recommend you take it to a shop if you are considering this mod; unless you're somewhat mechanical.

Weiboy718

iTrader: (10)

Please check out this post before considering the lightweight under drive pulley

Nissan 370Z Forum - View Single Post - GTM Performance Engineering stage 2 600hp supercharger kits line-up press release

Only4theGnme

It's very possible...because it happened.

I wasn't attacking your opinion of the mod...I was only offering my opinion of it, which was different from yours.

I did misinterpret your WTF comment....but only because it wasn't clearly stated...I know that there is an OBVIOUS dif in weight. You did say that there was little to no gain in this mod...that it was only for bragging rights. But in fact...a lighter weight pulley would spin faster, thus there has to be a gain of some kind...most likely in torque. But that's neither here nor there...that was your opinion and I respected it as such.

I wasn't attacking your statement or your opinion, just offering the OP a different one, my opinion of this mod made to this car and not a different car, since I actually made this mod to this car and not my "last" car, as YOU stated.

And I definitely noticed a difference under load after the making the mod, and still do now...again, thats my opinion. If your opinion is that there is no difference, I respect that...I just don't share that opinion because my experience with this mod is obviously dif from yours.

...there was no accumulative effect of mods at the time because the only other performance mod I had at the time the UDP was installed were the CAIs.

...if your opinion is different, that's cool...I don't have the same opinion. IMO...the mod was worth making.

Rochester

iTrader: (9)

Well, you're right that I've not put a lightweight crank pulley in my G, and I won't be based on my previous experience. So is it possible that on the 330 hp, 3700 pound G37 that an under-drive, or lightweight, crank pulley actually makes a difference? I suppose so, because anything is possible.

But I highly doubt it.

IMO

Only4theGnme

...now this is definitely worth paying attention to! In doing research before making this mod, I got mixed reviews, even from mechanics. But at the time the general consensus was that it wouldn't cause any harm, it just wouldn't give you huge gains in HP numbers, just torque gains. Is it possible that this damage was from the additional stress of the Stage II SC and a NA engine might not have this problem or was this damage done before the SC install and had to be removed to install the SC?? I couldn't tell from the post.

Weiboy718

iTrader: (10)

^ that's a negative. The car was about to get the GTM stage 2 SC installed at that time and was recommended to remove the pulley. When they tried to remove it, it is ceased due to all the heat generated from the engine and welded tightly together.

If you asks me, I would say it is not worth it for a few HP gains. That link is a perfect example.