For someone that clings so tightly to the science and physics, why do you now question the very basics:

Reducing rotating inertia improves acceleration and responsiveness.

Otherwise why would people run lightweight flywheels and/or smaller wheels?

 

True, but that just confirms the point.

Here we go: going to a lighter weight pulley on the VG30DETT increased rwhp because the UDP was lighter. The underdriving also had some effect.

Now, going to a lighter weight pulley on the VQ35 will also increase rwhp becuase the UDP is lighter. Not as much difference between the two pulleys as there is on the VG30DETT, but still a difference. Again, the underdriving also has some effect.

So, while I can only give anecdotal evidence on the possible engine damage (I had my UDP on there for about 85k, from 110k to 195k, when I had sold the car, it still ran strong, and as far as I know, a year later, it stills runs strong), I can give actual evidence, since I did do a before/after dyno with the UDP. It added 12 rwhp, and added torque throughout the rpm range. Of course, I don't have the dyno sheets anymore, I gave them to the new owner, so I doubt I will convince any of the confirmed doubters, but I doubt anything would convince them anyways.

Again, like I said, I am getting the UDP for my G, while it is still under warranty, even. No doubt if something goes wrong, my dealership will claim it voids the warranty, but thats the risk you take with any aftermarket modification.

Dave

 

Maturity at it's finest. You choose to bring up my Maxima, not me. Also, that extra 6" of roll out ain't gonna get you but more than around .5mph with a low 14-second car, Mr. Force.

 

I never disputed that reducing inertial weight improves acceleration and responsiveness. However a 10lb lighter 26" tire/rim combo is going to have a far greater improvement on performance (acceleration, launch, ride, and braking) than 4lb lighter 8" pulley mounted directly to the crank. The further the weight is from center of the rotating assembly, the more power it takes to spin the item in question (ie it takes a lot of power to spin a 26" tire/rim therefore if you remove weight from tire/rim and or push more of the weight towards the middle, the larger the gains). It takes very little power to spin a smaller 8" pulley mounted directly to the motor.

Lighter flywheels are great for road racing because they make it easier to stay in the rpms during shifts along with some marginal gains in power, however don't be mislead into thinking you'll be quicker at the strip with a lighter flywheel. A light flywheel has less moment of inertia which means the engine is far easier to bog on a launch. I even noticed this with my UR UDP on the Maxima. It takes more launch rpm and concentration to keep the car from bogging, spinning, bogging, etc. Once out of 1st gear gear and at WOT shifts everything is fine, but the most important part of a race is the 1st 100'. My friend even noticed he had to use 5500rpm launch on his LS1 Camaro SS vs his typical 4500rpm launch after he went with a 8lb lighter flywheel. He also noticed the car was far easier to bog and stall around town though he likes the flywheel for auto-X which is where he spends most of his racing time.

 

damn guys.... take a breath

The point is discussion...

Every bit of what DaveB has said is correct and accurate.
The responses should be about effect, application, etc...

I am way to old to play "my dick is bigger than yours", besides I don't care how big yours is....

Knowledge, facts, data - not pissing matches.

 

and in a previous post...

Dude you are talking in circles here, contradictions abound. You are arguing for the sake of arguing, and obviously have no more ground to stand on because you keep jumping topics once it's clear your arguments have no substance. I think it's time to put this one to bed.

 

I think you need to go back and reread my posts. You asked about rotational inertia and you got my answer and I said "useable gains" on the dyno or track. Gaining 2whp from Xrpms to Xrpms isn't going to make you any quicker in the 1/4 mile.

 

Sorry to break it to ya kiddo but there is a lot more to a sports car than 60' times and drag slips. Try some actual racing or even some spirited runs in the twisties and 60' times don't mean jack squat.

You have the mentality of a typical stoplight street racerboy

 

go back to the maxy pad club if you are so fond of your FWD floater. If you think you are impressing me bragging about your maxy pad times for comparisons to my car on another day on another track then you really are just mag racer wannabe. I beat every G timed that day except one coupe 6 speed that went 14.18 or so and tracked .3 better than most Z cars. I'll be at the June event in NJ so come to my bracket if you want to actually back up your BS. Quit dribbling. People have shown the gains you claim don't exist so you are left wanting....to argue.

 

Who's talking in circles?

I don't race on the street either. All my racing is done on the track under timers. As for auto-x, been there, done that, it's fun. It's too hard on tires though and I can't afford a full set of race tires/wheels and replacing tires every 5 events. I guess that makes me a racerboy

Dave B
Location: Overland Park, KS

That's a little too far me to travel to race someone. I guess that clearly means everything I say is BS

 

You said it. Hey if Chicago can make it from Chicago.....

You'd probably put 14's on and smoke everyone just to be ornery anyway. At least we won't have to drive into the water box like we did at ATCO and slip all the way to the 300' marker.

 

SixFive. . . . wouldn't it be nice to have 14's on the strip

DaveB . ... you are correct that the dampener is doing things like absorbing the shock of the A/C clutch engaging, or crank fan vibrations. On the opposite end, I am sure that the Auto-Tranny is probably absorbing some of this vibration due to the fluidic dampening nature of the torque converter. Perhaps we will see some associated issues with lightened flywheels for the 6MTs?

In the end, we probably are shaving some life off of our engines, somewhere from the 200/250k mile mark...down to say, 200k? I think if you concur, we can probably put this to out pasture as far CATO engine "timing". But we'll all be driving Infiniti GTR's by then and have a whole new host of issues to banter on about?!?

As far as the HP bennies, I think we'll all have to agree to disagree. This board lives for those discussion on any mod (ref Exhaust, Intake, Plenum threads). Again... it's the sum of all your mods.

cheers, Ted

 

First off DaveB Is dead right about the pulleys. I will be pulling mine off because here is another mod that killed drivability in my 6mt. I talking from off idle to 1500 rpms. Sure the pulleys make the car more zippy after you get the car moving. I do not like the fact that you have to run the belts so much tighter to keep them from squealing because of lost area of the pulley. I just wonder how long the water pump and alternator bearing are going to last with this much more load of belt tension. I have no idea what a lighten flywheel would do for drivability. A very old trick the drag racers used was to turn off there alternators with a toggle switch for a short 1/4 mile blast. I did this on my street cars for years and it worked great and that was true HP savings.
I want drivability at all rpms. But that's just me. Great thread
Dennis

 

Driveability was not the issue here, but rather power production.

I also used to use that alternator trick on my 5-liter rustangs. I wouldn't even THINK about it on this car, and judging by your grounding wire purchase, neither would you.

BTW, what would you be selling your pullies for? Joe Blow doesn't own a set yet.

 

If you somehow lost driveability at lower rpms then you have done something wrong. Never heard of such a thing...

They should last longer since they will be spinning fewer times per engine revolution. How is there that much more load tension than before?