whats up everyone

i recently installed my lord of the flies engine damper and works great and is a must have mod. its an extremely noticeable modification that enhances the sporty nature of the GP. you definitely need the magnet when installing though - the frame will digest any dropped bolts.


i have also ordered from Morristown mini -
JCW drilled rotors
JCW strut tower bar.

they should be here on friday hopefully. i wanted to do some basic up grades and keep the car as factory as possible. I figure these mods would help me in any stock class type racing i will venture into. also will keep my warranty intact


my next mod is going to be 16x7 advan rg2's with 215-45-16 azenis rt-615. this should make the GP more lively and feel faster. i figure handling should increase dramatically due to wheel weight, rotational inertia and increased grip of the tires. i want to order these in a couple days


my next mods i was thinking about were a test pipe / cel fix, lightened crank pulley, lightened flywheel / performance clutch. basically i want to exploit the full potential of the factory tune and factory supercharger components. any ideas on these mods and their benefits? are they worth it?

 

drilled rotors are not recommended on the track. The holes encourage cracks. You won't see drilled rotors on serious race cars, or even much at HPDE. I have seen drilled rotors with pie slices missing at HPDEs. Apparently this causes an unpleasant vibration under braking.

Of course all of the crank pulley & flywheel mods have a good chance of voiding warrantys. Lighter flywheel can affect balance of engine leading to crank failure. I don't know the history of cooper s engines. This is a real issue in many bmw engines: lightened flywheel == early engine failure. YMMV, but think carefully. Mods can mean less reliability. Less reliability can mean a lot of money and problems. I speak from experience. Your mechanic and the people who sell you the parts won't stop you. Buyer beware.

Obviously, the strut bar is just goodness, and anything you can get from mini won't be a problem, at least not for your warranty.


This doesn't mean I'll be able to resist modding my GP, but I'm really going to try this time. 8-) -------- 8-(

 

I second the lightweight flywheel/crankshaft pulley issue...Ive been trying to decide if i want to do the 2%alta pulley on my GP but have heard horror stories about pulleys without the dampening characteristics...

 

im not understanding the issue with drilled rotors. porsches still come with drilled rotors and thats about as close to a race car on the street you will get. granted a porsche drilled rotor is no Mini drilled rotor. but drilled rotors from Mini would carry the Mini warranty so i think this would be the best scenario in that Mini offers and recommends the use of this type of brake rotor. also would these premature hpde failure of rotors be caused from abuse in terms of warm up and cool down or the lack of? you can warp a solid rotor easily with out properly allowing it to cool down and being drilled i guess this would only quicken the ability to cool down a hot operating temp rotor with out a gradual decrease in temp - continuing to drive the car before coming to a complete stop? the holes in the rotor i guess would also decrease the strength of a warped rotor allowing for chunks to crack off? maybe there is some user error in rotor failures?

 

rotors are not warrantyed. they are expendables. If they were warrantee'd, the warranty would not be honored if they found out that you were tracking your car. Even if everything is just fine, you can use up a set of pads and rotors in about 6 days if you brake aggressively.

porche=race car for street, does not imply that you don't make changes for the track. Drilled rotors are nice on the street. They are lighter and are more responsive than solid rotors in the wet. There is no problem with drilled rotors for even -extremely- spirited driving on the street. The race track is a whole different thing. Just go down to the track and look for drilled rotors. You won't see them.

The problem isn't warping. The problem is cracking. Cracks spread from hole to hole in drilled rotors and you can really lose a pie shaped wedge, or just get a through-crack all the way across the rotor.

Long warm ups and cool downs are nice, but sometimes the give you the checker when you are 3 turns from the end and that's it. Now you are trying to cool your glowing rotors in the paddock.

Here is an example of other opinions:
http://www.superchargersonline.com/content.asp?ID=98
article on brake rotors. includes pixs of cracked drilled rotors.


http://flashoffroad.com/Maintenance/...akeRotors.html

some selections:
Darrick Dong; Director of Motorsports at Performance Friction: "Anyone that
tells you that drilling makes the disc run cooler is smoking crack."

Power Slot: "At one time the conventional wisdom in racing circles was to cross-drill brake rotors to aid cooling and eliminate the gas emitted by brake pads. However, today's elite teams in open wheel, Indy and Trans Am racing are moving away from crack prone, cross-drilled brake rotors in favor of rotors modified with a fatigue resistant slotting process."

Stop Tech: "StopTech provides rotors slotted, drilled or plain. For most performance applications slotted is the preferred choice. Slotting helps wipe away debris from between the pad and rotor as well as increasing the "bite" characteristics of the pad. A drilled rotor provides the same type of benefit, but is more susceptible to cracking under severe usage. Many customers prefer the look of a drilled rotor and for street and occasional light duty track use they will work fine. For more severe applications, we recommend slotted rotors." (Note that even though Stop Tech sells both drilled and slotted rotors they do not recommend drilled rotors for severe applications.)

Wilwood: "Q: Why are some rotors drilled or slotted?
A: Rotors are drilled to reduce rotating weight, an issue near and dear to racers searching for ways to minimize unsprung weight. Drilling diminishes a rotor's durability and cooling capacity."

From Waren Gilliand: (Warren Gilliland is a well-known brake engineer in the racing industry and has more than 32 years experience in custom designing brake systems ...he became the main source for improving the brake systems on a variety of different race vehicles from midgets to Nascar Winston Cup cars.) "If you cross drill one of these vented rotors, you are creating a stress riser that will encourage the rotor to crack right through the hole. Many of the rotors available in the aftermarket are nothing more than inexpensive offshore manufactured stock replacement rotors, cross drilled to appeal to the performance market. They are not performance rotors and will have a corresponding high failure rate"
From Baer: "What are the benefits to Crossdrilling, Slotting, and Zinc-Washing my rotors? In years past, crossdrilling and/or Slotting the rotor for racing purposes was beneficial by providing a way to expel the gasses created when the bonding agents employed to manufacture the pads...However, with today's race pad technology, 'outgassing' is no longer much of a concern...Slotted surfaces are what Baer recommends for track only use. Slotted only rotors are offered as an option for any of Baer's offerings."

Grassroots Motorsports: "Crossdrilling your rotors might look neat, but what is it really doing for you? Well, unless your car is using brake pads from the '40s and 50s, not a whole lot. Rotors were first drilled because early brake pad materials gave off gasses when heated to racing temperatures, a process known as "gassing out." ...It was an effective solution, but today's friction materials do not exhibit the some gassing out phenomenon as the early pads. Contrary to popular belief, they don't lower temperatures. (In fact, by removing weight from the rotor, they can actually cause
temperatures to increase a little.) These holes create stress risers that allow the rotor to crack sooner, and make a mess of brake pads--sort of like a cheese grater rubbing against them at every stop. Want more evidence? Look at NASCAR or F1. You would think that if drilling holes in the rotor was the hot ticket, these teams would be doing it...Slotting rotors, on the other hand, might be a consideration if your sanctioning body allows for it. Cutting thin slots across the face of the rotor can actually help to clean
the face of the brake pads over time, helping to reduce the glazing often found during high-speed use which can lower the coefficient of friction. While there may still be a small concern over creating stress risers in the face of the rotor, if the slots are shallow and cut properly, the trade-off appears to be worth the risk. (Have you looked at a NASCAR rotor lately?)

AP Racing: "Grooves improve 'cleaning' of the pad surfaces and result in a more consistent brake performance. Grooved discs have a longer life than cross-drilled discs."

 

Supposedly, Porsche rotors are done to their specs. They require that the holes are cast in when the rotors are manufactured, not drilled later on like most drilled rotors you see.

Most serious racers use slotted rotors to vent gases, not drilled. And of course, most racers change out rotors for every race, so minor heat cracking around non chamfered holes wouldn't be as big of a deal.

If you go drilled rotors, make sure to gradually warm up the brakes and rotors for a lap or two before getting on them. Less thermal stress with less change in heat, less chance of cracking.
Regards,
Jerry

 

A little bit more. This is from rennsport systems, bigtime porsche tuners:

the link has more than I've reproduced here. There is a very good guide to making your brakes work better on the track.
1) cooling system
2) brake fluid (after you've addressed cooling).
3) pads (after you've addressed brake fluid)
etc.

http://www.rennsportsystems.com/2c.html

"Porsche used cross-drilled rotors with mixed success. The Zimmerman rotors used on the 930 Turbo brakes were very soft and crack prone, even though the holes were chamfered. The later Brembo rotors will also show some wear when used with most performance brake pads. Some of the best rotors in the world are made in Britain by AP and Alcon. Those rotors, when properly adapted, seem to be superior to the Brembo ones in terms of wear and crack resistance. All drilled rotors will crack sooner or later if overheated. Slotted rotors are more durable in this regard however they are heavier. One reason that most large iron rotors are cross-drilled is to save some unsprung weight. Since nice big, light, carbon rotors cost $1000 each, saving some weight without bankruptcy, is important. Plus, carbon rotors possess very little friction until they reach 500-600 degrees F. Porsche's PCCB ceramic matrix rotors while very light, seem to have mixed success when used for track events.
"

 

And to date I still have (now) $400 on the table to anyone who can prove this great 'cast in holes' comment. So far, about 3-4yrs later I still have the money and more info on rotor casting than I care to remember. But none of it providing any evidence of such parts. In fact their own literature is quoted as "drilled". But I remain open minded and will pay to play.

Now, back to your regularly scheduled thread....

 

great info everyone. so seems like i will try the jcw rotors and after my beggining hpde event ill see how i handle the car and take it from there. ill definitely keep an eye out on cracks and fatigue. ill go with the stock rotors as i get better. the car is gonna be a mostly street/weekend car for now.

have any of you road racers / auto x'ers installed a crank pully, competition flywheel or crank pulley? any reliabilty issues or premature failures? any gains?

 

I have the M7 2% lightened crank pulley on my GP. I love it and have NO problems, vibrations, noises,.......nothing. Love it.

 

cool, that may very well be my next mod.

my rotors came in - they look pretty sturdy and are slotted as well as drilled. this may add some strength as the slots are in place of more drills maybe allowing for a higher strength. i dunno, but they look cool and should work great having both technologies. oh yeah, the holes are chamfered and are quite small. pics to come.

the strut bar is very light and very shiny. i hope the added rigidity is noticeable. the bling is definitely noticeable - its a nice piece. it does not look like a $224 part but hey its factory so the premium is not so bad.


i am placing the order for my advans/falkens now!!! better handling and grip here i come!