Oh and einstien? Why are the ford v-8's producing profound gains with a udp if gains are physically impossible? I know you refute all dyno results but 8-15 ponies is outside most margins of error.

 

Let me try and sum it up for you in a way that you might understand.

1) Underdriving. Frees up power by increasing the mechanical advantage on the accessories. 20% underdrive frees up 20% of the power used to drive any accessoriese run off of that belt, in general. If the Ford V8s use a 20% underdrive and their accessories consume 50 hp, then I'm sure they result in 10 hp gain.

2) Lightening. Frees up power by reducing the inertia that must be angularly accelerated by the engine. Gains are percentages of the engine power and differ in each gear. For the G35, it's generally a couple hp in 1st, and less than 1 hp in the higher gears. I go through the details of this calculation in the link I posted previous. It is not "copied and pasted" from a textbook, but derived (very simply) by myself from first principles.

3) Bogging on launch. You have stored angular moment in your rotating assembly before launch. When you attemp to launch, your driveline is rotating at a different rate (generally 0) than it would be if rigidly connected to your engine at whatever engine RPM at which you're launching. Thus there is a torque generated that attempts to decellerate your engine to match your driveline speed once you attempt to join them through the clutch, and how quickly the engine decelerates is a function of the inertia of your rotating assembly and the power output being varied by the throttle. The more engine inertia you have, the more buffered the launch is and the less sensitive it is to perfect throttle control off the line. This is the same reason why it's easier to accidentally stall a car with a very light flywheel.

Nothing magical here. But you can continue to make a fool of yourself if you wish.

 

Good point. With a non-RevUp motor, I probably wouldn't do until you add the RevUp rod bolts. The non-RevUp motors were prone to dumping the connecting rods thanks to weak rod bolts. Nissan addressed that problem. I know that a lot of the 95-99 Maxima guys that swap in VQ35 blocks are utilizing the RevUp rod bolts so that they can run 7500rpm with little worry.


It has a lot to do with the fact that the Ford V8 pulleys are in fact 2 and 3 pulley sets including a new crank pulley, water pump pulley, and sometimes and alternator pulley. Underdriving the water pump results in most of the gain. With a VQ, the water pump is driven off the timing chain therefore you're not underdriving the water pump.

I found this very interesting. Sean Hyland Motorsports (SHM) is one of the more respected Mustang tuners. As taken directly from thier website (note the bold), you can see that they believe the OEM harmonic damper is VERY important and take note of the way the Ford pulley looks in comparison to the VQ pulley. They're almost a direct match.

 

Well I guess staying away from the 7100 mark and TS is a good idea for now. In the meanwhile, I've done about all I can do to make this car run like a beaatch NA.

As for the level of ridiculousness we stooped to it was great fun for a while. But, unfortunately, no else seems to want to dare step in here and chat with us anymore. Since it's yet to be shown with real world test that either side is correct I guess we'll have still have track days and textbooks. I've always been one for using products such as DaveB did and then coming to conclusions. I still hope to find the conclusions on this topic but I'll never buy into munchee's going and on about how shedding weight from a rotating mass doesn't allow that mass to accelerate faster, but we don't have to agree - this isn't a space shuttle launch. Now I'm off to watch the upset of the year!

 

Go Texas

 

SixFive
Well, I guess staying away from the 7100 mark and TS is a good idea for now. In the meantime, I've done about all I can do to make this car run like a beach NA.
Sorry Bro. Its not the time to throw in the towel just yet.
There are a few more things for you to do, Lets just call it finer tuning. Your a great poster, and ask great questions. Damn I wish we had owe SIGs back. I bet I can find you a few more HP. and better ET's ,,,,,,,,,,,,,, Your old buddy Pasta

 

SixFive may post a lot but he sure can't follow a logical argument to save his life!

Case in point:

Regarding the game, I'm about 1 mile from the Rose Bowl currently and could watch the game live with some binoculars.

 

According to my wife, I can't follow an illogical argument either...

And go they did! Should have mortaged all the property and bet it on Texas. They gave the heisman to wrong guy..maybe they should have given 2 out this year... Can't wait to rub this into my Texas A&M alum friends this weekend....Go buckeyes

 

Sig's back

 

Hahahahahaha.

 

Pasta: What's my gameplan for adding some ponies and bettering the ET's? Was thinking of checking my AF and spark plugs. Does anyone know if my crawford cats have a pre cat bung for a better AF reading? I forget...

I still get giddy thinking about my first run ever at ATCO after the pulley was installed. Maybe I'll dig up the video later and post it. I still think my AT was the only one the squealed the tires going into 3rd that day...gotta love the Turanza AS's

 

Here's a pretty OK read I found a while back.
http://www.nissanperformancemag.com/august04/specv/

This actually shows that gains were made (supports my theory) and that they were minimal and only at the bottom end (supports opposing theory).

 

The shape of those curves with respect to the "gains" tells you right away that it's most likely just run-to-run error and variability. Most repeated runs on the exact same car vary more than that from run to run. But assuming the curves are accurate, what it for sure tells you is that the "lightening" is making no significant power (less than 1 hp) as we predicted.

Pure lightening will result in a "stretched" power curve (gains are a percentage of the engine output). Gains from underdriving should simply offset the torque curve, but that could vary if different accessories consume different amounts of torque at different rotation rates. Basically since the gains are effectively zero at high RPM, those dynos tell you that the lightening is doing essentially nothing (fractions of 1 hp, as predicted for those engine acceleration rates in my unsolved misapplied textbook theories). ALL "gains" are coming either from error and variability, or if you are in love with the dyno and assume there is no error or variability, then variations in the underdrive torque gains from different torque vs rotation rate specs for the accessories.

 

Good call on the Upset! I was loving that ending!!!

I am glad to see you and DAVE B are still around...Man so many new names, etc...on here...the place looks totally different too...and no sigs any more...

So has anyone cracked my 14.0 @ 100.7 mph in an NA auto with stock exhaust???

Man am I behind...I just got the new Z-Mag and I had to come on here and look up all these new 05-06 Terms like REV UP, etc...lol...Take it easy man...

 

Hey stranger; no one I know of has beaten that mark with an Auto G of any kind coupe, sedan or 280hp version. You kicked some serious butt after the TS install. You still da man. Oh and sigs are back, you just have to retype them.

I'd love to get a race on with you sometime...but with a little princess on the way it may be hard for me to get to NE even tho I've been meaning to get to Manchester for a while now.

And that was the best football game I may have ever seen. And I've seen Ole miss at LSU in person!

Oh and Boss, did you put on a UDP?