How fast is your 968?
01-22-2008, 10:56 AM
#46
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I meant, do you know at what RPM the stock valves begin to float? Or is it at such a high RPM to not be an issue?
Some of the racing rules allow you to change the rev limit, but not the internals of the head. If the stock valves begin to float at a low RPM, there is no reason for me to raise the rev limiter.
Some of the racing rules allow you to change the rev limit, but not the internals of the head. If the stock valves begin to float at a low RPM, there is no reason for me to raise the rev limiter.
I was told to keep the stock valve train to stay under 7450 rpms. I had new stock valve springs. I do not know if that's the limit but you would not want to run the motor over that RPM anyway. -Mike
01-22-2008, 11:33 AM
#47
So that seems like a 7000 redline is not dangerous. For those of you who think your speedo is off, post your rear tire sizes and whether you are a 5sp or 6sp and I can give you the actual speeds of the wheels at specific rpms so you can see how much larger tires affect the speedo reading.
01-22-2008, 12:03 PM
#48
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H2 you should come on down and run an open road race, there a few new guys coming down from Washington state for the 08 season. Nothing like running the car all out! Keep in mind your running at an altitude from five to seven thousand feet.
It’s a blast no matter what speed class you run, we ran 150+ for almost 50 miles in the PE130. Seriously you should consider running one of the MKM events in “June or August” We are getting the car ready for the NORC in May
Matt
It’s a blast no matter what speed class you run, we ran 150+ for almost 50 miles in the PE130. Seriously you should consider running one of the MKM events in “June or August” We are getting the car ready for the NORC in May
Matt
I would love to run one- Mike
01-22-2008, 12:23 PM
#49
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Raj
01-22-2008, 02:25 PM
#50
Three Wheelin'
Join Date: Jul 2001
Location: San Francisco, CA Porsche: '92 968 Blk/Cashmere
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01-22-2008, 03:15 PM
#51
Hey Mike,
Yes you need to add some safety equipment, my first race I was in the 120mph class – Tech speed is 140mph. I needed a 5 point harnesses and a 2.5 lb minimum, automotive BC fire extinguisher. Full Face SA Helmet and a set of gloves, to my surprise I could add the 5 point harness using the Bay Krause mounting kits without drilling a bunch of holes in the car. Max speed in this class is 140mph if you go faster and they catch you with one of there hidden radar traps you get disqualified, the same rules apply up till the 125 class.
For the Pony Express 130, last August we added the following and entered the 130mph class
Auto Power Bolt in Roll Bar
Driving suite “SFI 3-2A/5”
Padded helmet supports (“horse collars”)
Arm Restraints
Racing Gloves & Shoes
For tires you would need W minimum but (Y) (parentheses) tires (186+ mph rating) are highly recommended.
Our tech speed jumped to 168mph, so we can run the car as hard as we want and never exceed our tech speed. We did hit 163mph in practice; race day was windy so our max speed was just over 155mph. All the rules are available on-line @
http://www.openroadracing.com/html/rulebook.html
If you want to take a look at our full run start to finish Click Here
There are speed classes from 85mph to 170+, the lower classes "up to 110 with a 124mph tech" all you need is a fire extinguisher, helmet and a set of gloves
Yes you need to add some safety equipment, my first race I was in the 120mph class – Tech speed is 140mph. I needed a 5 point harnesses and a 2.5 lb minimum, automotive BC fire extinguisher. Full Face SA Helmet and a set of gloves, to my surprise I could add the 5 point harness using the Bay Krause mounting kits without drilling a bunch of holes in the car. Max speed in this class is 140mph if you go faster and they catch you with one of there hidden radar traps you get disqualified, the same rules apply up till the 125 class.
For the Pony Express 130, last August we added the following and entered the 130mph class
Auto Power Bolt in Roll Bar
Driving suite “SFI 3-2A/5”
Padded helmet supports (“horse collars”)
Arm Restraints
Racing Gloves & Shoes
For tires you would need W minimum but (Y) (parentheses) tires (186+ mph rating) are highly recommended.
Our tech speed jumped to 168mph, so we can run the car as hard as we want and never exceed our tech speed. We did hit 163mph in practice; race day was windy so our max speed was just over 155mph. All the rules are available on-line @
http://www.openroadracing.com/html/rulebook.html
If you want to take a look at our full run start to finish Click Here
There are speed classes from 85mph to 170+, the lower classes "up to 110 with a 124mph tech" all you need is a fire extinguisher, helmet and a set of gloves
01-22-2008, 05:41 PM
#52
Nordschleife Master
Based on my transmission calculator, your speedo is way off. Your speed at 6500rpm on those tires with an S2 tranny is calculated to be 120mph. 6500rpm in 5th would net you 159mph.
01-22-2008, 07:34 PM
#53
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So, that's about a football field per second.....quick stops at that speed would be difficult....how many seconds? A lot.
Also, not just any tire is rated for the higher speeds. A few years ago a brand new 911 (996 or 997, I forget) blew a front tire at just over 200mph on one of the Nevada runs. He died and the rest of the runs that event were canceled.
There are strict requirements for the open road runs, including roll cages at the higher speeds. It's not something you can do without a lot of preparation.
To achieve the highest speeds they remove mirrors, tape over headlights, seams, etc. At those speeds every little bit makes a difference. Also, the wind resistence becomes a major thing, requiring the additional HP.
Harvey
Also, not just any tire is rated for the higher speeds. A few years ago a brand new 911 (996 or 997, I forget) blew a front tire at just over 200mph on one of the Nevada runs. He died and the rest of the runs that event were canceled.
There are strict requirements for the open road runs, including roll cages at the higher speeds. It's not something you can do without a lot of preparation.
To achieve the highest speeds they remove mirrors, tape over headlights, seams, etc. At those speeds every little bit makes a difference. Also, the wind resistence becomes a major thing, requiring the additional HP.
Harvey
01-22-2008, 07:57 PM
#54
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Someone asked about horsepower. I think Tahoe Shark's NA Silver 928S4 (6.4L) was pushing 500-525HP. When you factor in the weight difference between the 928 and 968, I'm not sure what HP would be required to achieve 200mph in the 968.
H2
H2
01-22-2008, 08:38 PM
#56
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At that speed, weight is almost irrelevant. It's all aero efficiency. HP vs air resistance. If a 968 has the same coefficient of drag as a 928 then it would need the same hp, regardless of weight differences.
01-22-2008, 09:58 PM
#57
edco....cool video. We need a 968 contingent at the Pony Express. Have you ever seen a 944/951/968 running there?
H2
H2
Bill Ball - 1989 928S4, 145 class
Gorj7 - 1990 928S4 "Supercharged" 160 class - Looking to join the 200mph club
Tahoe Shark - 1988 928S4 "6.4L" 160 class & 2 time 200+ club member
Richard S - 87 928S4, 135mph class
Paul M - 2006 Z06 in the 150 class
edco - 1988 928S4 moving up to 135 class
StevenB - 1989 928GT "Rookie" running the 120 class
A 944 contingent at any of the events would be awesome, come on out and I'll buy you a cool drink
01-22-2008, 10:40 PM
#58
Drifting
We have a stretch of road we call highway 5 here in Kansas. Sits right on the missouri border, so cops are never around. A buddy had a 1995 Honda prelude, SOHC F22 motor. We did all of 105 or 110. That motor makes like 150hp if that. 3 people in the car.
That SAME stretch, I did 135mph in my car, one passenger from a dead stop (spinning through first gear). So you mean to tell me I managed only 10mph more over a 150hp Honda that was loaded with 600+lbs of people?
I think not. Trust me. I have seen how fast cars go buy at 110mph in my toyota truck, and it wasn't nearly as fast as cars going by at 140mph (both speeds done on the same stretch- 70mph zone). Not to mention when I was doing the 140mph run, I had a girl passenger who was loving every minute of it as I put bus lengths on a '00 Honda prelude with H22 DOHC motor (same buddy that had the '95 prelude).
I swear that calculator is wack.
Not trying to be a dick about it or anything, but I'm going off what the speedo says...and I highly doubt it's off by 10mph at 70, 14mph at 103, and 20mph at 140. I've kept pace with cars on the highway and been verified at certain speeds. With and without my 18's.
My 16's sizes were 205/55/16 and 225/50/16.
Last edited by CarbonRevo; 01-23-2008 at 01:14 AM.
01-23-2008, 09:29 AM
#59
Nordschleife Master
Yea, and 2nd goes to 60 and 3rd to 89. Trust me, it does more then that in each gear because I'm giving rsx's a rear shot of 285's every time pulling 2 cars on them, and over 3-4 cars at 120mph.
We have a stretch of road we call highway 5 here in Kansas. Sits right on the missouri border, so cops are never around. A buddy had a 1995 Honda prelude, SOHC F22 motor. We did all of 105 or 110. That motor makes like 150hp if that. 3 people in the car.
That SAME stretch, I did 135mph in my car, one passenger from a dead stop (spinning through first gear). So you mean to tell me I managed only 10mph more over a 150hp Honda that was loaded with 600+lbs of people?
I think not. Trust me. I have seen how fast cars go buy at 110mph in my toyota truck, and it wasn't nearly as fast as cars going by at 140mph (both speeds done on the same stretch- 70mph zone). Not to mention when I was doing the 140mph run, I had a girl passenger who was loving every minute of it as I put bus lengths on a '00 Honda prelude with H22 DOHC motor (same buddy that had the '95 prelude).
I swear that calculator is wack.
Not trying to be a dick about it or anything, but I'm going off what the speedo says...and I highly doubt it's off by 10mph at 70, 14mph at 103, and 20mph at 140. I've kept pace with cars on the highway and been verified at certain speeds. With and without my 18's.
My 16's sizes were 205/55/16 and 225/50/16.
We have a stretch of road we call highway 5 here in Kansas. Sits right on the missouri border, so cops are never around. A buddy had a 1995 Honda prelude, SOHC F22 motor. We did all of 105 or 110. That motor makes like 150hp if that. 3 people in the car.
That SAME stretch, I did 135mph in my car, one passenger from a dead stop (spinning through first gear). So you mean to tell me I managed only 10mph more over a 150hp Honda that was loaded with 600+lbs of people?
I think not. Trust me. I have seen how fast cars go buy at 110mph in my toyota truck, and it wasn't nearly as fast as cars going by at 140mph (both speeds done on the same stretch- 70mph zone). Not to mention when I was doing the 140mph run, I had a girl passenger who was loving every minute of it as I put bus lengths on a '00 Honda prelude with H22 DOHC motor (same buddy that had the '95 prelude).
I swear that calculator is wack.
Not trying to be a dick about it or anything, but I'm going off what the speedo says...and I highly doubt it's off by 10mph at 70, 14mph at 103, and 20mph at 140. I've kept pace with cars on the highway and been verified at certain speeds. With and without my 18's.
My 16's sizes were 205/55/16 and 225/50/16.
Based on your tire size of 285/30-18. That tire actually has a smaller diameter than your 225/50-16s and hence will give you a lower speed at any rpm.
Last edited by Lemming; 01-23-2008 at 02:59 PM.
