yeah, its fun spinning them at 100 mph. i am going to have to get at the least some 295 BFG DRs for my rims and see how that helps out. alan used to have some 265s and said they gripped a lot better than the pirelli pzero rossos (285) that are on there now.


well it looks like this thursday will start the fun. i have to work all day today, tues, wed and most of the day thurs, then i am off till monday possibly longer if i would like. i am yanking out the motor out of the G on Friday, anyone in the area want to stop by and help/get in the way feel free to call me...

 

Did I hear Refi ??? You have my number call me if you need help or advise on the refi I will let you know if you got a good rate and deal or not. I dont want to see a friend locked down with somthing he does not need...I am a broker...

 

Roebling - was fantastic. The weather was great, low 80's partly cloudy, low humidity, no bugs and a slight breeze. Track was in great shape and there where a lot less drivers than the NASA event. Yet, the NASA event was much better organized and the instructors where also a lot better at NASA. The classroom stuff was a joke at this event as compared to NASA. Yet, the other drivers where great people, and it was much better to have 25 min sessions as compared to 20 min. I did hit 146 mph coming into the braking zone of turn 1, and hitting 95 mph in turn 3 - so I was going much faster than the NASA event. My heal-toe is getting better, yet I need to move the brake pedal out on the Z as it is so much lower than the gas pedal.
This was the last event there before they re-pave it, so next time we are there it will be a whole new track, I won't have the nice sealer on turn one to give me a marker for the initial turn in .

Video from Roebling: http://www.vadennissanparts.com/moody61806.wmv

 

Nice vid man you do really enjoy your car...

 

mike, i have a question, after gutting your car out a bit more, can you tell any difference in traction.

i was wondering if it hurt or helped, less weight to push down on the tires but less weight to drive forward as well...


i have the car up on jackstands now, no wheels, brembos, or front bumper cover. i should have the motor out on friday, i will start a thread and i have a bunch of pictures to post up...

 

Great question, this is one that stumps most drivers. We all understand that traction increases as vertical load on the tire increases, but the relationship is not linear. Let's say that the load force is 200#, then the traction force for this tire is lets say 200#. Now add on 500#, so the load is now 700#, but the traction force is now only 550#. This means that you will have more traction, but now you have to push 700# with only 550# of force, thus you loose traction. If that makes sense? The important thing to do with weight is to get it as little as possible but equally distrubuted over the car. This way all the tires are going to give the max amount of grip as possible.

Now as far as my experience, yes I did feel like I had a lot more grip. Yet, I am more concerned with my cornering, braking and acceleration out of a turn. It really felt easier without that 100# and when my 200# insturctor got out of the car, WOW.

Now, areodynamics give you downforce with out adding weight to the car. That is why F1 cars have such huge wings, so they add verticle load to the tires and gain more tire traction force without having any weight added to the car. Thus, they are able to achieve more than 3.5g's in a turn! Yet, don't think my car will ever be able to achieve those numbers, more like 1.0 to 1.3 g's is possible with our cars. But, it takes so much work to get over 1.05 g's!

 

cool... great answer!!



i was just wondering about putting this engine in my car that is a good 700 pounds lighter, well... what my outcome will be.

i have started and hopefully will have it in by sunday...

 

As your car gets lighter and your engine makes more power, your car's performance will get more violent. Small suspension changes will make a bigger difference than they made before. Parts will break that you never considerd before.

But it will be loads of fun and a great ride... Be careful...

 

Dan IMed me with "how is alans motor 700 pounds lighter??" hehehe i guess i should use punctuation for the slower people.... jk


jb, i know theoretically what the outcome will be, i was just wondering real world with a similar car, when mike took out 100 pounds, what he thought about it....

 

Lighter cars will also have less momentum that you are trying to change directions on. It takes less lateral force on a tire to turn a 2500 lb vehicle than it does to turn a 3400 lb vehicle. The tires (being the same make/width) will have the same lateral limit, but the lighter car will be able to take the turn with more speed as the momentum it is carrying will be the same as the heavier car at a slower speed. Did that make sense?

2500 lb car at a 1.15g turn is putting 2875 lbs of lateral force on the tires.
3400 lb car at a .845g turn is putting 2875 lbs of lateral force on the tires.

Those g's that the cars are acheiving will depend on the speeds that they are running. Assuming the turns are the same radius, the 3400 lbs car will have to travel at a slower speed.

I think/hope I did that correctly. I know downforce and suspension have factors too, but I'm trying to keep it simple.

 

Generally speaking you are correct. But, your CG also plays a huge part. Even if you have a lighter car, if the CG is way up high, the force on your tires could be even greater than a heavier car that has a really low CG (center of gravity). That is why you lower your car.
Also, how the tires are loaded, even if you have a lighter car, if the driver inputs don't match the suspension set up of the car. That is why it is not always better to have stiffer springs and/or stiffer sway bars. The stiffer these are the smoother the driver has to be.
There is so much more to handling that it is not funny. That is why I really think it is easier to achieve better hp than better cornering/braking. But, in general the two best mods you can do to increase perfomance is:
1. Tires
2. Weight reduction
Yet, you should always first invest in safety before trying to increase performance (something that I really need to do and will in the next few months)

 

Very good vid Moody I will be getting to Roebling soon but plans are for Sebring first.I am going to get really serious with attending track days soon. Next week I plan to be sporting a 03 WRX which will be tracked alot.I plan on touching the power a little at first then setting up brakes, suspension,tires/wheels,then back to more power.I need something cheaper to play with and not worry about so much.So the 350z will be missed because it really is by far the best all around car I have ever owned.
Eric

 

So you are going AWD, well you will find that you can lay on the power sooner exiting a corner than you could with a Z. Yet, you will also find more power loss through the drive train. But, the WRX is a great car - did you get the hatch back or the wagon. I believe the wagons are stiffer in the rear and handle better, plus it would be cool on track to pass people in a wagon!

 

i know he is not getting the wagon, i mean he wants four doors already for his family, i dont think he needs MORE room than that!!

 

Roebling is a great track for an AWD car like that and the Evo. I drove my instructor's Evo around Roebling last year and it was some of the most fun I've had drifting around those turn. I was giggly like a little girl. You'll love that car. The brakes should come first, you'll find that the stock WRX brakes suck.