Slow In, Fast Out - LotusTalk

apk919 · 09-22-2009, 10:06 PM

I was looking at two laps that I ran last Saturday at the Cal Speedway ROVAL... trying to figure out why the slower lap actually started out faster; what had I done differently?

The answer is this: on the slowest turn on the track (in the middle of sector 5 on the track map), preceding a long straightaway, the faster lap actually had the slower apex speed by 2.5 mph! But because that allowed me to get on the throttle earlier, my eventual terminal speed on the long straightaway afterwards was 5 mph <b>faster</b>, essentially creating a 1 second gap between the two laps.

A very graphic example of the principle of slow in, fast out!

The blue lap is the faster lap, the red the slower. The cursor on the graph below is at the slowest point in the turn (just before the apex). The bottom trace shows the time gap between the laps... you can see the time gap increase dramatically on the straightaway in sector 6.

Chili Red · 09-22-2009, 10:35 PM

I love data for this very reason.. There is really no other way to tell what works and what does not effectively..

On a side note, I never did like the saying slow in fast out. There is nothing slow about entering a corner correctly. Slow in fast out always seemed to imply that you need to go into a corner overly slow to come out quicker and that is just not the case as you probably know..

My driving coach always preaches fast in faster out for this very reason. He also preaches never do anything that will take your gas pedal away as the sooner you can get on throttle the faster you will be (especially with a long straight following).

erics75218 · 09-22-2009, 11:18 PM

very cool!

ZJChaser · 09-23-2009, 01:27 AM

nice use of the data! I'd really be curious to see the difference as well that a few mph make at the apex of the banking....if possible with similar starting speeds. I've lazy on my data logging lately. I haven't pulled the memory card out of my car yet since that event.

Tracktimeplz · 09-23-2009, 06:16 AM

Looks like you made some considerable improvement in turns 3 and 6 as well.

Fun stuff!

apk919 · 09-23-2009, 07:14 AM

Thanks guys!

Chili... you're right... it's not exactly "slow" in... and as you said, the most important thing about your line/speed through the corner is how early you can get back to consistent power.

AJ... I just did a few simple calculations... on the red lap, my entry speed into sector 2 was 129.5 mph, average speed was 124.5, exit speed 127.9. If I could have maintained the 129.5 mph throughout the whole sector, the time would have dropped by 0.55 seconds....

09-22-2009, 10:06 PM	#1 (permalink)
apk919 ΒÄŅNED Join Date: Oct 2007 Location: Limbo Posts: 6,281 Images: 20	Slow In, Fast Out I was looking at two laps that I ran last Saturday at the Cal Speedway ROVAL... trying to figure out why the slower lap actually started out faster; what had I done differently? The answer is this: on the slowest turn on the track (in the middle of sector 5 on the track map), preceding a long straightaway, the faster lap actually had the slower apex speed by 2.5 mph! But because that allowed me to get on the throttle earlier, my eventual terminal speed on the long straightaway afterwards was 5 mph <b>faster</b>, essentially creating a 1 second gap between the two laps. A very graphic example of the principle of slow in, fast out! The blue lap is the faster lap, the red the slower. The cursor on the graph below is at the slowest point in the turn (just before the apex). The bottom trace shows the time gap between the laps... you can see the time gap increase dramatically on the straightaway in sector 6. Attached Images __________________ * 2009 Lotus Challenge Series Rookie Of The Year * (Thanks Jim, Tom, Jack, Rob & Spring Mountain Motorsports Ranch!) My videos: http://www.youtube.com/user/apk919 Last edited by apk919 : 09-22-2009 at 10:26 PM.

09-22-2009, 10:35 PM	#2 (permalink)
Chili Red Registered User Join Date: Dec 2006 Location: Houston, Tx Posts: 2,204	I love data for this very reason.. There is really no other way to tell what works and what does not effectively.. On a side note, I never did like the saying slow in fast out. There is nothing slow about entering a corner correctly. Slow in fast out always seemed to imply that you need to go into a corner overly slow to come out quicker and that is just not the case as you probably know.. My driving coach always preaches fast in faster out for this very reason. He also preaches never do anything that will take your gas pedal away as the sooner you can get on throttle the faster you will be (especially with a long straight following). __________________ 2007 Exige S - Chili Red 2009 Mini Cooper S - Chili Red Gotham 265, Nitron Sport Pro, Moroso oil pan, RTVBrace, Volk CE28N/R888, Cup Wheels/A048, 2Bular Ultra 4", Rapfix II w/ Sparco P300, S111 CF Splitter, Ultradiscs, Pagid RS42, V-Force Harness Bar, Schroth PROFI II, Fire Extinguisher, Folding Tow Hook, Odyssey PC680, re-ENFORCER, LLumar 30% tint, Traqmate, DashDAQ, Chasecam, Alpine IVA-D100 w/ Backup Camera.

09-22-2009, 11:18 PM	#3 (permalink)
erics75218 Registered User Join Date: Dec 2004 Posts: 570	very cool! __________________ 06' Exige C H R O M E O R A N G E Hire me to do Visual FX http://www.ericsmithcg.com/ exigevideos.com my depot of the best Lotus videos online http://exigevideos.com/

09-23-2009, 01:27 AM	#4 (permalink)
ZJChaser Blue Wheel Pimp Join Date: Aug 2006 Location: Laguna Hills, CA Posts: 2,851	nice use of the data! I'd really be curious to see the difference as well that a few mph make at the apex of the banking....if possible with similar starting speeds. I've lazy on my data logging lately. I haven't pulled the memory card out of my car yet since that event. __________________ AJ - Akua Solutions - #128 Lotus Exige - JRZ Suspension - Innovative Mounts - Toyo Tires - TW Research Development

09-23-2009, 06:16 AM	#5 (permalink)
Tracktimeplz Race lines on the mind Join Date: Apr 2008 Location: Northwest Florida Posts: 1,085	Looks like you made some considerable improvement in turns 3 and 6 as well. Fun stuff! __________________ 2003 Honda S2000 - Suzuka Blue 2005 Magnetic Blue Elise Forcefed 275 turbo - Sold 05/20/09

09-23-2009, 07:14 AM	#6 (permalink)
apk919 ΒÄŅNED Join Date: Oct 2007 Location: Limbo Posts: 6,281 Images: 20	Thanks guys! Chili... you're right... it's not exactly "slow" in... and as you said, the most important thing about your line/speed through the corner is how early you can get back to consistent power. AJ... I just did a few simple calculations... on the red lap, my entry speed into sector 2 was 129.5 mph, average speed was 124.5, exit speed 127.9. If I could have maintained the 129.5 mph throughout the whole sector, the time would have dropped by 0.55 seconds.... __________________ * 2009 Lotus Challenge Series Rookie Of The Year * (Thanks Jim, Tom, Jack, Rob & Spring Mountain Motorsports Ranch!) My videos: http://www.youtube.com/user/apk919 Last edited by apk919 : 09-23-2009 at 07:22 AM.

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