mark kibort

I thought the cup cars , even the very old ones, were getting to 155mph , and they cant have much more hp than you, no? If so, that is a great example of HP /drag ratios just being limited.
If anderson is doing 170, i would think I would be able to hit 160mph, as I got 155 at road america with a bone stock, 20 year old engine with only a set of headers.

I wonder if I could have the nerve to get to that speed!

Tom W

Yes, the cups were getting in excess of 150, if not 160. I'll ask Rich what his MoTeC said (for a '10 cup) or Mike could chime in for his '09 cup. They have a lot more hp than me and better aero. My little putt-putt makes about 275 at the rear wheels and torque is about 250. The GTL class rules yield engines that are very similar power (I think we are all within about 5 hp of each other - I know the 3 or 4 engines built at Jerry Woods are).

It was cool/cold last weekend so we might have been a bit faster due to the weather too.

fleadh

On Sunday my best top speed was 158.45, I'll check the Motec data for Saturday as it should have been slightly higher with stickier tires giving a better run onto the front straight. The '10+ cups have a little more HP, but I think they also have a little more drag.. so I'd imagine our top speeds were fairly close.

-mike

tlarocque

My buddy running his near stock 996 GT3 was seeing 150-152 mph (speedometer indicated) consistently. He ran a 1:54.00 on well worn MPSC's. I hit 150 a couple times but pussed out and used some brake before turning into 1.

IcemanG17

I saw 250km/h in the video....997 cup car I am guessing....nice 156mph!!!! Taking the corner at over 140mph has to be NUTS.....WOW..... I don't think my bucket can even go 140mph!!!

Spec Miatas have to be silly on this course....bouncing off the rev limiter in 5th at 125mph or something.....

Anderson can hit 170mph....but has quite a bit more HP and torque than even the Cup cars.....

IcemanG17

MK
You could do it...no doubt....

you can get 130+ at Thunderhill...... Even my bucket gets 120mph if conditions are right.....

I wonder how much faster Andersons 130whp gets him compared to you....maybe 10mph?

mark kibort

yes, it does get 130 at thunderhll now, solid. 122ish with the old motor , and I even got a solid 140mph first time out with a blazing tail wind. thought the speedo was off, because it was the first time in this car on the track, but when the wind died down, it was back to the usual 130mph max.

its really about 140 rwhp, and i think 10mph sounds about right. BUT, i cant imagine pulling the cup cars down the straight with almost the exact same power. if they are seeing 155, thats probaby what I will see. I think the 928 is probably pretty close to frontal area and obviuosly wing, to a cup car.
Hard to imagine I couldnt go faster, because it seemed like at road america, that straight wasnt that long AND it was mostly uphill. the banking must cause a lot of rolling friction as well as the slide loading, so its probably not as long as it seems.

makes me feel better about going if max speeds are in the 155 range. thats not scary with my set up now.

Your bucket doesnt do 120 now, your speedo is a little off due to the tires. (305, 26" tires vs your 245s) However its probably around 115 I would bet. (100hp difference vs the holbert 320wrhp getting 122-5mph)
50hp got me near 5-8mph. Its hard to say. Its going to be great when we all have data aqu on board, to take all the guess work out. a lot of this stuff doesnt add up sometimes.

jrgordonsenior

Yep the weather combined with a open turn out to the banking would account for those lap times. I raced against a couple of those same cars there just a few weeks ago and they were 2+ seconds slower then.

Aero plays a huge part in top speeds obviously. My 996 only has 267 RWHP but I make 155 mph thru the banking in 5th gear. 6th is actually slower.....

claykos

Why would your 996 have so much lower drag than a regular, narrow body 6 cup? These cars would have ~350-380 rwhp depending on year and are only hitting around 155 or so?

mark kibort

I just figured out from the video , why speeds of faster than 155 are not happening. evnen though the cal speedway straight is near 30 seconds long, 2x of road america, where cars like mine get to 155, you really only have 17 seconds of WOT before you hit the banking, where everyone seems to lift, or the rpm seems to stagnate due to the banking G forces and compression drag. , then on the exit, there is only about 3 seconds where you hear a slight acceleration, but not much happens in 3 seconds at that speed. I have a new term for that................net HP-seconds. Its not very much at that point on the track for anyone. i think anderson gets to 170mph before the banking.

JR, its amazing you get to the same speeds as the cup cars with less hp. i woudl think that your lighter weight is a trade off in getting to the top speed of 155. Its a hp to weight thing, more than an aero thing, due t the fact that your car could probably go 170 if the straight was long enough. (and the cup cars more like 180-190 if they could have the gears to do it) If you have an better less drag aero package, that would help a lot too. I think the answer has to do with your body style. isnt the cup car much wider than the stock 996 of '99? remember how the cup cars at daytona vs the GT3RS had 10mph more top speed, due to the narrow body? maybe the same thing is going on here too.

btw, what is your weigiht again? i thought you said it was 2550 with you in the car vs 2750lbs for the cup cars w driver.

NJ-GT

Speedo is way off in all modern Porsches. 152 mph indicated is about 146mph actual, 150mph indicated just 144mph. Plus a 996 GT3 has less drag (less downforce too), so in stock form it can't take the bowl at 140+ mph.

My 996 GT3 (turning 1:52 on RA1 4 years ago at CalSpeedway) reached a top speed (actual Traqmate speed, not the speedo overrated stuff) of 151.05 mph, but at the apex of Turn 1&2, I could not pass 121.79mph, Rookie driver in fast car.

The Cup cars have too much drag, top speed is not their strength, but they lap Cal Speedway several seconds faster than street cars, by being able to hold Turn 1&2 at full gas (and I think JRGordon does this as well).

jrgordonsenior

Clay I was referring to Tom's wide-body 964. I agree cups share identical bodies to my 996. I'm lower in the front at CS which gives me a slightly better aero profile (see avatar) as I run 680 rears there vs. my normal 650's.....

jrgordonsenior

Mark I'm 2600 w/driver on fumes. My 6-cup was around 2775 w/driver. IIRC I hit about 160 mph into T1/2 there. I distinctly remember Bobby Fiaeta telling me his data said he was at 166 when his RR tire blew in front of me several years ago. Scary, but he luckily spun harmlessly down into the infield. Cups runa 4:00 R&P versus my street 3:44 R&P which is why I'm in 5th gear....

Oh and I asked both Patrick Long and Kris Wilson if they lifted heading into T1 and they both said yes. This was right after they were turning high 1:40's in 6-cups. Also interesting, neither went up high entering T1 but stayed down low near the white line....

claykos

I thought you said you were hitting 155 in your 996 with 267 rwhp?

I hit around 154 in my black 993 bodied car with 350 rwhp. I was able to go flat all around the oval (not every lap, but a couple of times).

I hit 174mph in my old Factory Five Cobra with 640 hp! Now that was CRAZY. Open cockpit, no windscreen, 7800 rpm in 4th - just a lift before entering the oval corner would brake at .8 Gs from all the drag!

Tom W

Don't confuse max speed observed due to (lack of) power and aero with max speed limited by grip and aero.

Remember that while some of us with putt-putt cars can take T1 & T2 flat and max out our speed, the cups are not flat and are limited by grip. Rich said that his highest speeds were before T2 as he had to lift there. As he was running 1:39's, I have to believe there wasn't much extra room left for improvement. Johannes also said that he didn't think it could be done flat in a later cup.

I tried to upload some video with data overlays last nigh but You Tube said it was too long and deleted it. I'll try again tonight.