soc_fans

Before i start, sorry i did not bring my video cam with me to the short race. ( we did 2x)

I have a 997s with EVO headers and Fabspeed mufflers, with 20" Techarts. (Don't start flaming at me about the 20's! They are not as heavy as what i expected to be)

The Evo8 has alot of tuning on the engine (Intake, Straight pipe, exhaust, etc)

Rolling start from 30mph-100mph; started at 2nd gear. (Sport button, PASM on) I started pulling on him at 60mph about 1 car length and at end of the race i was 2-3 car lengths ahead. Same thing happened when we tried the 2nd time.

I was so suprised when i pulled on him during the race as i thought with my 20's it would slow my car down pretty badly. With the evo headers, it really opens up my top end.. i never felt that way with the stock headers.

I will definitely bring a video cam for the next race with another of my friend's E60 m5 and Mercedes E63. I hope i will not disappoint you guys!

mountainmaniac

20s!!?? What is wrong with you!? You are an idiot! I can't believe you would have 20s!!! Oh my god, that is ridiculous! Dumbest thing I have ever heard! You should be tarred & feathered!! Your car is slower, heavier, & uglier than ours!!!

Kidding aside, I too am pleasantly surprised to hear this. It always makes me a little nervous to have an obviously-modded (i.e. coffee can muffler might also mean chip, larger turbos, etc.) Evo or WRX stalking me. Thanks for the info!

D.D.

awaiting info!!

Hartley

IMHO the slight added weight of 20's and the performance hindrance they may haver is severely over exaggerated by many forum members. They are not going to suddenly make the car a slug. Any race will still be a drivers race.

99firehawk

unsprung weight makes a huge diffrence in performance

ChrisF

I'm kind of surprised to hear this since I own both cars. My lightly modded stock turbo EVO VIII I'm pretty sure would kill my 997 on a low/med speed roll. The EVO is geared much lower. It's also fairly common for a stock turbo EVO VIII to make over 400 crank HP with a few bolt on mods and a tune. Would be curious to know what mods your friends EVO has. Either way, congrats.

Hartley

Got any documented facts to back that up? Surely 50lbs per wheel would make a difference but lets say 5lbs extra per wheel.

RonCT

Documented facts on the effects of weight on performance? That's pretty rudimentary - that lower weight = higher performance. At what point does weight become important? Ok, if I add just 5 lbs per wheel, that doesn't change performance at all, but once I get to 10 lbs, that's when there's a drop? It's linear - 10 lbs is 10x as bad as 1, 5 is 5x, etc. Granted, you might not be able to perceive 1 extra lb, but it's there nonetheless.

Here's the simple wiki on it:
http://en.wikipedia.org/wiki/Unsprung_weight

http://www.bluegooseriders.org/riders/roadracing.html
This is a Biker's site, but the theories are sound.

Weight is directly related to horsepower. It is estimated that every seven pounds you eliminate, gains one horsepower.
There are many benefits to reducing unsprung weight. One of the most noted is that, 1 kg of reduction in unsprung weight is approximately equal to 6kg reduction in sprung weight.

One easy way to reduce unsprung weight is the use of lighter weight wheels. By reducing the weight of the wheels, you also reduce the gyroscopic effect. The gyroscopic effect is the force that is generated from a spinning object. To get an idea of what this is, hold a bicycle tire in your hands and spin it. Now try and change the direction of the wheel. You will notice it is hard to do especially if the wheel is heavy. By reducing weight in the wheels you will reduce this effect resulting in better handling during cornering and improved acceleration. Magnesium wheels are the choice for most Superbike racers, and some are even going to carbon fiber but these are very expensive and typically not as durable as cast aluminum.
+ + +

So, if you can remove 70 lbs from your car, it's like adding 10 hp. Better yet, if you remove 20 lbs of unsprung weight (say 5 per wheel), that's like removing 120 lbs of weight, which is like adding 17 hp.

This is why performance minded racers and drivers are constantly seeking ways to reduce not only weight but more importantly unsprung weight. I'm chasing 2-piece rotors like the PFC ones currently made for the base 997. I'm on a notification list from PFC for when they start making rotors for the 997S because they should be about 4 lbs lighter per wheel. One of the reasons I stuck with Pilot Sport Cups is they are the lightest R-comp out there at 25 lbs each (vs. upwards of 30 for something from Toyo / Nitto). Same with wheels - light weight 18s at say 20 vs. others at 25 or 30 lbs.

I'm just saying - don't underestimate the impact of weight all around. Tires, wheels, rotors, stuff in the trunk (some guys snicker when they see me taking everything out of my car at the track - the tool kit, compressor, maps, etc.). It all goes in my track box and probably weighs 50 lbs, equivalent to 7 more hp

texas911

Yea, I had an EVO 8 and its way way quicker in low speeds than in top end. I wouldn't say 997 quick, but pretty quick. Once that turbo kicks in, it all hell breaks loose. Quite fun.

Edgy01

Weight has always been the challenge for racers,--but just how much are you willing to spend to shave off a lb? Isn't that the real challenge for the weekend racer,--how far they are willing to go for a buck?

Hartley

Sure weight counts but the people that say adding 20" "kills" performance are over exaggerating just a tad. I'd love to see a true back to back test, say 0-60, 1/4 miles, 0-150, 25-75, etc.

My point is, the addition of 20's would likely not add much more than a 1/10th or 2/10th in any of those which won't make anyone lose any races as drivers error is easily the same between runs.

I'm not saying go racing on 20's but on a street driven car, it doesn't matter that much for most to even worry about. If one cars so much about racing and weight savings, they should also skip the Nav or CD changer, power seats and Bose audio, etc. Maybe better yet, buy a GT3 instead.

gmoney99

It does not sound like it was tuned:

----The Evo8 has alot of tuning on the engine (Intake, Straight pipe, exhaust, etc)

Tuned in the Evo world is ECU flashed / dyno tuned etc. Your looking at 380hp with a tune and full exhaust (stock intake, filter) on an Evo 8 from one of the good places. Thats enough HP to make quick work of a 997S from my experience.

I have a V400 vishnu tuned IX MR and she puts down 330 to the wheels on a dynojet with just a tune and full exhaust. Even from a roll or move shes fast (unlike stock ones that are pigs from a roll). Vbox's 4 flat 0-60 and low 12's when launched like you hate it.

Porsche_Smile

from a stand still.... you will get killed.... once you're into the higher speeds, the evo can't keep up......there gear ratio is set for only 0-60 mph... after which, it's just a cruiser....

gmoney99

4.53 gearing and 330 at the wheels makes for some crazy 0-60 times, thats for sure.

Porsche_Smile

i agree... their 0-60 is insane... and when they re-chip it, WTF..... the things a beast... but that's all you got........ you look great from stop light to stoplight..... but what's after...?