Lowering VRT Question
Thread Starter
Racer
Joined: Oct 2001
Posts: 310
Likes: 0
From: Brooklyn NY
Lowering VRT Question
Assuming that your C5 A4 has a torque converter with a 2800-RPM stall, at what RPM to you launce for the best Vehicle Reaction Time? (Vehicle Reaction Time is the time your car needs to start moving after you have stepped on the throttle)
What I am trying to do is lower my VRT so that I can launce at the third yellow. My average reaction time to the light is 0.12 seconds but my VRT is about 0.5 seconds. That gives me a 0.62 to 0.66 second reaction time when I launce on the third yellow.
I tried to stage “deeper” but I was unsuccessful in producing consistent results. I can’t stage “deep”, turn the pre-stage lights off. My assumption is that the only way to guarantee that the car is always at the same spot on the stage line is to either stage “shallow”, i.e. barely light the stage lights or stage “deep”, i.e. turn the pre-stage lights off.
Any suggestions?
What I am trying to do is lower my VRT so that I can launce at the third yellow. My average reaction time to the light is 0.12 seconds but my VRT is about 0.5 seconds. That gives me a 0.62 to 0.66 second reaction time when I launce on the third yellow.
I tried to stage “deeper” but I was unsuccessful in producing consistent results. I can’t stage “deep”, turn the pre-stage lights off. My assumption is that the only way to guarantee that the car is always at the same spot on the stage line is to either stage “shallow”, i.e. barely light the stage lights or stage “deep”, i.e. turn the pre-stage lights off.
Any suggestions?
Le Mans Master
Joined: Feb 1999
Posts: 6,172
Likes: 11
From: somers, ny
Re: Lowering VRT Question (Hex29A)
higher RPMs should lower your VRT. As will more air in the front tires, smaller front tires, reducing unnecessary vehichle movement, reducing weight (especially rotating weight) or as you already i mentioned going in deeper. if you have .120 r/t, you are way quicker than the avg person (avg being around .200), but if your car is really .500...that's slower than the avg (12-13 sec) car. Also be aware that most people anticipate the last yellow on a full tree. My r/t on a protree is about .210-.220, but that drops to about .160-.170 on a full tree (no matter how hard i try to focus on only the last yellow).
Race Director
Joined: Oct 1999
Posts: 13,298
Likes: 14
From: Somers NY
Re: Lowering VRT Question (ralph)
Try just staging, keep the RPM at about 1500, then just "bump" it in 1 time sorta quickly pump the break ONE time.. This should move your car forward about 3-4"... try that 3 or 4 times, & see if your reaction times are staying consistent..
IF... repeat IF they are, & you are still mid to high 5xx then bump it in 2 bumps...
It works for me... I think its worth a try on a test & tune day..
[Modified by Red96Coupe, 10:39 AM 6/25/2002]
Thread Starter
Racer
Joined: Oct 2001
Posts: 310
Likes: 0
From: Brooklyn NY
Re: Lowering VRT Question (ralph)
higher RPMs should lower your VRT. As will more air in the front tires, smaller front tires, reducing unnecessary vehichle movement, reducing weight (especially rotating weight) or as you already i mentioned going in deeper. if you have .120 r/t, you are way quicker than the avg person (avg being around .200), but if your car is really .500...that's slower than the avg (12-13 sec) car. Also be aware that most people anticipate the last yellow on a full tree. My r/t on a protree is about .210-.220, but that drops to about .160-.170 on a full tree (no matter how hard i try to focus on only the last yellow).
You must be right about my R/T (0.12 sec been to quick). I'll setup the tree with 0 second rollout and see what numbers I get when I hit the pedal at the 3rd yellow.
Thread Starter
Racer
Joined: Oct 2001
Posts: 310
Likes: 0
From: Brooklyn NY
Re: Lowering VRT Question (Red96Coupe)
Try just staging, keep the RPM at about 1500, then just "bump" it in 1 time sorta quickly pump the break ONE time.. This should move your car forward about 3-4"... try that 3 or 4 times, & see if your reaction times are staying consistent..
IF... repeat IF they are, & you are still mid to high 5xx then bump it in 2 bumps...
It works for me... I think its worth a try on a test & tune day..
IF... repeat IF they are, & you are still mid to high 5xx then bump it in 2 bumps...
It works for me... I think its worth a try on a test & tune day..
I assume you are talking about a “staging” technique.
As far as RPM are concerned, I am trying to establish a relation between the torque converter stall and the launch RPM. The 15K RPM you are referring to, is it what you do from experience or is it related to my 28K theoretical torque converter stall?
Race Director
Joined: Oct 1999
Posts: 13,298
Likes: 14
From: Somers NY
Re: Lowering VRT Question (Hex29A)
John
I assume you are talking about a “staging” technique.
As far as RPM are concerned, I am trying to establish a relation between the torque converter stall and the launch RPM. The 15K RPM you are referring to, is it what you do from experience or is it related to my 28K theoretical torque converter stall?
I assume you are talking about a “staging” technique.
As far as RPM are concerned, I am trying to establish a relation between the torque converter stall and the launch RPM. The 15K RPM you are referring to, is it what you do from experience or is it related to my 28K theoretical torque converter stall?
Also I find it easier to stage at 1200.. (I get no heat in the trans/converter) also I don't have to STAND on the breaks real HARD.. I can bump in a little if I want,
Some cars will like to have a higher RPM at launch, but my BEST 60' 1.65 was at 1200 rpm..
I'm going to install a new 3200 converter this week, & will have to test to see my best method for launching...
[Modified by Red96Coupe, 11:45 AM 6/25/2002]
Team Owner
Joined: Nov 1999
Posts: 32,782
Likes: 11
From: Former NCM Drag Racing coordinator, National director Corvette Challenge Spring Hill, Tennessee: Whiting, New Jersey
Cruise-In VI Veteran
Cruise-In VII Veteran
Re: Lowering VRT Question (Red96Coupe)
I'm going to install a new 3200 converter this week, & will have to test to see my best method for launching...
[Modified by Red96Coupe, 11:45 AM 6/25/2002]
[Modified by Red96Coupe, 11:45 AM 6/25/2002]
Elite Torch Red Member
Joined: Sep 1999
Posts: 57,805
Likes: 23
From: Exit 89 GSP,Lakewood,NJ The Land Of Mojo
Cental/South NJ Events Coordinator
CI 1-2-3-4-5-6-7-8-9-10-11-12 Vet
CI-II Burnout & Drag Champ
St. Jude Donor '03-'04-'05-'06-'07
Re: Lowering VRT Question (mackeyred96)
I'm going to install a new 3200 converter this week, & will have to test to see my best method for launching...
[Modified by Red96Coupe, 11:45 AM 6/25/2002]
I hope it's better than my 4400 :(
[Modified by Red96Coupe, 11:45 AM 6/25/2002]
I hope it's better than my 4400 :(
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