Deciphering straight line speed

#1

I’ve heard this too many times now about people (not always me), “He just pulled away from me on the straight he must have a ton more power than me”

Or some version of that racers crutch.

Here are two laps from my traqmate data, that can illustrate the importance of how critical turn 7 is and doing it properly. This is a 1.474 vs. a 1.483 and nearly half of that time gap (ie 1/2 a second) is right in this one turn.

I overslow the car by 2 mph and at the end of the straight it is almost 3 mph and that equals 1/2 a second difference.

Consider what that would look like if you were the guy that braked a tick too hard going into 7 and I’m the guy that did it ‘right’, add in the draft you’d get from staying behind the lead car and you could see as much as a 5mph or more difference at the end of the back straight. Something to consider before you think the guy behind you has a V8.

In fact many of the answers about going faster can be found in studying the data. If I had a choice between a $3k motor and a $3k data system I’d take the data and work on understanding it. What you can learn with that information will outlast the 3-5 extra HP. [file name=Back_Straight.jpg size=97300]http://spece30.com/media/kunena/attachments/legacy/files/Back_Straight.jpg[/file]

#2

Good post. Completly agree.

#3

Another thing I had the infamous HP graph on this as well. I’m around 150 for the entire run except when going downhill into 12 where it goes up to like 200. So data is powerful but you have to understand and use it in context.

The graph resolution is poor due to this wonderful forum software. If anyone wants the real version, or if you’re a SouthEast racer and want the actual traqmate files email me and I’ll send.

Jim

#4

Jimmy, Obviously you are talking about my comments. I had the occasion to come off seven with Seth in tow and I was dead ass even with him. Half way down the straight (moved over so he couldn’t draft) he motored away from me like I didn’t have a motor at all. I’d be happy to trade traqmate data with you.

#5

Nope sorry Steve I’ve said this myself about other people too. No passive aggressive weirdness here or anyone specific just hoping to satisfy my own curiosity more than anything.

I’d always ‘heard’ the most important corner is the one before a straight but this shows it, or at least it did to me.

#6

Jim,

That’s a great info. Thanks for sharing a portion of your upcoming book ‘Racer-X Speed Secrets Vol #1’ with us (Hardcover $49.95).

P.S. - Could you send me a copy of that traqmate file?

#7

Steve, I assume it was Franklin Futrell who set the fastest lap in E2 (enduro) by over half a second in your car, right?

#8

TheRedBaron wrote:

Now why would you make the assumption that Franklin was driving it? :wink:

Yep, the boy is just wicked fast.

#9

Everything that Jim says is dead on. But if you exit 7 with a car, are in their draft, and they just drive away from the draft about a third of the way to T10A, you might have an engine that is a bit down on power.

#10

I underestimated how popular my mediocre laps would be, so I’ll make this easy for everyone (except Patton who isn’t good w/ dem computors).

http://dtomracing.com/traqmate

There is a .zip file that you can download. I just pulled everything off the TM so there may be some garbage files of a few minutes in there. The fast laps are in Saturday practice, Sat. race, and Sunday race.

Seth turned a 1.47 in the enduro, I was able to get to 1.474 in Sunday’s race. So while the motor is probably 98% of the equation I think the nut behind the wheel is doing okay too. Different days, tires, cloud formations ie apples to oranges disclaimers apply.

A few conditions:

a) buy stuff from Clay & BimmerWorld since he and Seth have taught me anything I know about racing and data. It isn’t just for me either, I know Clay is happy to help any customer and answer any question I’ve seen someone ask.

b) if you’re still convinced its the motor call Brendan Digel at RWL German Imports and tell him you want the Geegar / Robinson half a$$ special - 404-588-1624.

c) if you see anything of interest that I’m doing right or wrong tell me, I look at this stuff to get faster (and so should you)

Enjoy.

#11

Jim, since I ain’t no good at computers, just tell me the bottom line…

Oh, wait, youse already did. Robert is an 75 golfer.
Skeen, Swartz,Allen,Cobetto,Hunter, etc., are 68 golfers.
If we swap golf clubs, they’ll still shoot a 68 and I’ll shoot a 75.

Okay, their clubs might be better. Naw, that’s just an excuse.
Well, I can have excuses, can’t I? By the way, you had better brakes and breaks than I did in Sunday’s race. I’ll get ya next time.

I need more practise at my game.

Regards, Robert (sometimes I can shoot a 70)Patton

PS, where is the DTOM report? I wanna see my name in the report so I can brag to my friends that I made to the DTOM page.

#12

and in our game it isn’t the club - its the ‘balls’…

#13

Hey where the deuce is JP? If I hear him whining one more time about how I pulled him at Rockingham cuz of motor, I’m gonna flip. It’s all driver. Jim just proved it. Eat it JP.
Man, this armchair racing is a lot easier than getting out there and wrenching.
-Vic

#14

Excellent thread. After e-mailing Jim and some others my data from December, I thought I would add it to the thread. Obviously, the weather was great on that weekend for setting fast times, but I think there is still a lot to learn from it.

Anyone that wants help reading data or a second opinion at the track, let me know. It’ll be cheaper than building a motor. Just ask Ranger. :wink:

[file name=Road_Atlanta_SpecE30_Michael_Skeen_3_001.zip size=406493]http://spece30.com/media/kunena/attachments/legacy/files/Road_Atlanta_SpecE30_Michael_Skeen_3_001.zip[/file]

#15

I got no Data
I got no HP (latest greatest motor 144hp)
And my balls are shrinking from old age.

Any suggestions?

Al

#16

Take up golf?

#17

I’m honored that you guy’s think the engines I built have the juice, but the fact is compared to the Sunbelt engine they really are half A$$, Theese engine not only aren’t overbored but I reused the orignal pistons,Some of you are so focused on one thing that not only do you not see the " Forest though the trees", you don’t see the tree though the bark. Jim has put a lot of effort in being a good student of the sport, He looks, at every thing, he puts a lot of effort in to the entire car, ie If i tell this gut he has a wheel bearing that feels slightly rough, hell show up a with 4 wheel bearings, 2 half shafts, and want to rebuild the diff, If I tell him there is a split boot on a tierod end he shows up with two tie rods, two control arms, new lolly popsand bushing and a steering rack! My wife asks on fri nights what are you doing to jims car this weekend??? Not only Does JIM put a lot of effort into the car he has put a lot off effort into improving as a Driver, though DATA, Video and coaching from his ringers,and working on his Fitness. Jim Recently went to VIR with me for a BMW race to co drive my 535, last year my best lap was a 2.15, with Jims data, him coaching me and some changes we made to the car I turned consistent 2.10s, and finally , this guy snice late 2007 has lost 40ish pounds to improve his fitness in the car, how many of you have put that much effort in to it??? BAM

#18

Brendan, I just read your post and it is obvious to me why Jim’s got it going-on.

He moved 40 pounds from the front left position to the rear of the car. Better balance. Geez…why didn’t I think of that?

Again, congratulations to Jim on his RA wins. He has worked diligently on his game and it shows. I’ll get him at the next RA ecvent in August.

RP

#19

40 pounds? That just proves he will go to great lengths to cover up his dirty, rotten, low-down cheating. Winky winky winky. Bastard. Winky wink.

Steve D.

#20

The pills Jones gave me helped, but made me cry a lot.