Low speed at the track?
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 2,238
Likes: 4
From: Milan
Low speed at the track?
I made a new personal record at the track:
11,5 secs in a 90°F day in an Italian track (an Airport).
The track is not prepped ..only some "glue" on the first 100 meters.
What is concerning me is the (relatively..) low speed.
I made all day in between 11,7 11,6 and 11,5 secs as the best.
The very best SPEED is 189,8 km/h = 118 mph .
my 396 ci engine in my 1990 C4 is very strong but it seems I loose something when I put the 3rd gear (AUTO 700R4 manually shifted).
(7.283 at 1/8 mile)
Is a 118 mph (average of the day was from 116 to 117 mph) a LOW speed?
I say this because I WON many passes with others cars very slow at the start but very FAST at the end ..
-Beppe-
11,5 secs in a 90°F day in an Italian track (an Airport).
The track is not prepped ..only some "glue" on the first 100 meters.
What is concerning me is the (relatively..) low speed.
I made all day in between 11,7 11,6 and 11,5 secs as the best.
The very best SPEED is 189,8 km/h = 118 mph .
my 396 ci engine in my 1990 C4 is very strong but it seems I loose something when I put the 3rd gear (AUTO 700R4 manually shifted).
(7.283 at 1/8 mile)
Is a 118 mph (average of the day was from 116 to 117 mph) a LOW speed?
I say this because I WON many passes with others cars very slow at the start but very FAST at the end ..
-Beppe-
Last edited by conv90; May 15, 2012 at 11:14 AM.
Safety Car
Joined: Apr 2005
Posts: 3,624
Likes: 431
From: Dale City VA
What rear gear do you have?
What size tire?
Auto or 6spd tranny?
If auto - whats the TQ converter stall.
Your 1/8th mile MPH is about 93mph which is inline with a small tire car car running a 7.28 1/8th ET....
With that kind of 1/8th MPH I'd expect to see 120mph in the 1/4.... but everything depends on the rest of the drive train.
A really powerful manual tranny car can pick up 30+mph in the backhalf of the track where as a big tire car with an auto and alot of converter may only pick up 15mph.
Will
What size tire?
Auto or 6spd tranny?
If auto - whats the TQ converter stall.
Your 1/8th mile MPH is about 93mph which is inline with a small tire car car running a 7.28 1/8th ET....
With that kind of 1/8th MPH I'd expect to see 120mph in the 1/4.... but everything depends on the rest of the drive train.
A really powerful manual tranny car can pick up 30+mph in the backhalf of the track where as a big tire car with an auto and alot of converter may only pick up 15mph.
Will
Safety Car
Joined: Feb 1999
Posts: 4,724
Likes: 16
From: Little Elm TX
I made a new personal record at the track:
11,5 secs in a 90°F day in an Italian track (an Airport).
The track is not prepped ..only some "glue" on the first 100 meters.
What is concerning me is the (relatively..) low speed.
I made all day in between 11,7 11,6 and 11,5 secs as the best.
The very best SPEED is 189,8 km/h = 118 mph .
my 396 ci engine in my 1990 C4 is very strong but it seems I loose something when I put the 3rd gear (AUTO 700R4 manually shifted).
(7.283 at 1/8 mile)
Is a 118 mph (average of the day was from 116 to 117 mph) a LOW speed?
I say this because I WON many passes with others cars very slow at the start but very FAST at the end ..
-Beppe-
11,5 secs in a 90°F day in an Italian track (an Airport).
The track is not prepped ..only some "glue" on the first 100 meters.
What is concerning me is the (relatively..) low speed.
I made all day in between 11,7 11,6 and 11,5 secs as the best.
The very best SPEED is 189,8 km/h = 118 mph .
my 396 ci engine in my 1990 C4 is very strong but it seems I loose something when I put the 3rd gear (AUTO 700R4 manually shifted).
(7.283 at 1/8 mile)
Is a 118 mph (average of the day was from 116 to 117 mph) a LOW speed?
I say this because I WON many passes with others cars very slow at the start but very FAST at the end ..
-Beppe-
Mine picked up 24 mph every pass in the 2nd half of the track.... so did yours. And I picked up 4.2x et in the 2nd half of the track every pass..... so did you.
Considering it did it in 90 degree temps at an unknown track altitude, I think you're running pretty good. My only comment, is that your 60 ft is a little slow.... if you didn't spin, then you have another 1-2 tenths of et hidden in your et through improved 60 ft times. (I ran in the 1.5's every hook pass with a 3000 rpm Vig and 3.45 gears) What converter are you running ?
However, if this is a manual, your 2nd half track mph pick-up is a little down as Will said. They typically pick-up a little more depending on power and gearing.
Congrats and good luck improving your et !
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 2,238
Likes: 4
From: Milan
OK,
Rear is a dana 44 taken from a ZR1 3.45 ratio.
I recently switched from a 17" drag radial to 15" MT ET Drags
---> SO the time slip i posted is WITH 28.0/11.5-15 on 11.25 rim .
Converter is a Vigilante 3200 on a 700R4
I have to add that the low 1.6 secs at 60 IS MY best.
As I said the track is not a real drag strip, but an airport prepped with some "glue". I always Have to be carefull with th gas pedal at the start.
When it hooks for sure I'm not 100% on gas pedal.
Qa1 front set to 90/10 ... It lift the front but I have NO skinnies bUT regular 275/17 tires on front
Rear is a dana 44 taken from a ZR1 3.45 ratio.
I recently switched from a 17" drag radial to 15" MT ET Drags
---> SO the time slip i posted is WITH 28.0/11.5-15 on 11.25 rim .
Converter is a Vigilante 3200 on a 700R4
I have to add that the low 1.6 secs at 60 IS MY best.
As I said the track is not a real drag strip, but an airport prepped with some "glue". I always Have to be carefull with th gas pedal at the start.
When it hooks for sure I'm not 100% on gas pedal.
Qa1 front set to 90/10 ... It lift the front but I have NO skinnies bUT regular 275/17 tires on front
Melting Slicks
Joined: Dec 2008
Posts: 2,772
Likes: 64
From: Mystic CT
What does the dyno sheet look like at the top end? If it makes all the power in the mid range and noses over on top then you will lose MPH on the top as well. I would worry about et first and not sweat a mph or 2. I would focus on launching the car so suspension and seat time. Whatever you can't hook up is et loss left on the table to get, it would help the 60 ft time a bunch as well. You said you get on it when it finally hoks up how far down track is that 2 ft 20 ft or? If your rear spring is as stiff as the stock one in my 91 I would think way too stiff
Dave
Dave
Safety Car
Joined: Apr 2005
Posts: 3,624
Likes: 431
From: Dale City VA
That 28" tire is KILLING you with the 3.45 gear you have....
Either get a 26" tire or a 4.10 gear.... both if you want to set the car up specifically for 1/4 mile racing.
I'm calculating that your only turning 4850RPM going thru the traps.... That means your car is in 2nd gear from before the 1/8th mile marker to right before the 1/4 mile timing lights....
You want to have the car in high gear (1.1 is 3rd gear in a 700R4) for along as possible.... thats where the converter and tranny eat the least amount of power.
Will
Either get a 26" tire or a 4.10 gear.... both if you want to set the car up specifically for 1/4 mile racing.
I'm calculating that your only turning 4850RPM going thru the traps.... That means your car is in 2nd gear from before the 1/8th mile marker to right before the 1/4 mile timing lights....
You want to have the car in high gear (1.1 is 3rd gear in a 700R4) for along as possible.... thats where the converter and tranny eat the least amount of power.
Will
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 2,238
Likes: 4
From: Milan
That 28" tire is KILLING you with the 3.45 gear you have....
Either get a 26" tire or a 4.10 gear.... both if you want to set the car up specifically for 1/4 mile racing.
I'm calculating that your only turning 4850RPM going thru the traps.... That means your car is in 2nd gear from before the 1/8th mile marker to right before the 1/4 mile timing lights....
You want to have the car in high gear (1.1 is 3rd gear in a 700R4) for along as possible.... thats where the converter and tranny eat the least amount of power.
Will
Either get a 26" tire or a 4.10 gear.... both if you want to set the car up specifically for 1/4 mile racing.
I'm calculating that your only turning 4850RPM going thru the traps.... That means your car is in 2nd gear from before the 1/8th mile marker to right before the 1/4 mile timing lights....
You want to have the car in high gear (1.1 is 3rd gear in a 700R4) for along as possible.... thats where the converter and tranny eat the least amount of power.
Will
BUT... only if I were in a USA full prepped track!.
I decided in a COUNSCIOUS way to buy 28" tires INSTEAD of a 25,7" I was before.
With a Hoosiers 315/35/17 full DRAG-radial tyre (25,7" tire) traction (in the not prepped italian strip) is like crap! there is NO WAY to hook! the first gear is useless .. even using partial gas pedal.
So I decided for the 28" 15 tire.
BTW I'm able now to use the very short gear (very very short 1st gear in a 700R4..) , but I'm paying the taller tire during the 2 to 3 gear change)..
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