1/4 mile questions - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Hotrodding Basics
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 10-15-2005, 09:44 PM
Member
 
Last photo:
Join Date: Sep 2004
Location: wichita, KS
Age: 41
Posts: 126
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
1/4 mile questions

Ok so I took my car to the track and need some answers if anybody can anyway. 4 years ago with my 351C I pulled a 15 flat best time with a 3.00 peg leg rear end and stock convertor, I changed out the to a 3.80 posi rear with a 2500 stall. and my times are almost identical. the 0-60, end speed and ET. shouldnt something have changed. I mean instead of bogging or roasting my tire I actually launch now but my times are the same. the only real difference I know for sure is that I cant drive it on the highway anymore. is there something im missing. I am at a complete loss. if anybody can shed some light on this for me I would appreciate it. I can also post any info that would help in figuring this out.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 10-15-2005, 10:04 PM
Siggy_Freud's Avatar
Hotrodders.com Moderator
 
Last photo:
Join Date: Dec 2003
Location: Portland, Oregon
Age: 29
Posts: 2,371
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
The car would have to be running considerably worse for that to be the case. What is your timing both base and full advance set at? What RPM do you have it coming in by? How are you staging at the lights? Are you wheel spinning a lot? What do you plugs look like? Have you modified the engine at all?

Lots of questions to be answered lol.
__________________
Bringing history and technology together.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 10-15-2005, 10:15 PM
New Member
 
Join Date: Oct 2005
Location: 40 minutes north of NYC
Posts: 18
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Yes some thing should have changed But 4 years how many more miles and what else has been done do the car/engine ?

I would say you now have a base line number to work with to improve.

How did you do with your timing? Read the articles below I sent a link to and get the car in proper tune.

Ill share a quick story I used to be into sledding. and one of the best things were the fellows used to go thru the vendor books and get every go fast assesory the could get and put them on there sleds. Studs,pipes,re jetting air boxs. and they would never really tune there sleds. I would make a simple clutch weight spring change,jet down a size and use a hotter plug and whip there butts,

I am not bragging here just pointing out that proper design and tune should be what your after.You want to build an entire package not just peices of go fast parts. If I remember correctly you changed a cam. Where is the cam making its power? what year cleaveland do you have. My 70 cleavland was a heavey breather and made power up on the top of the rpms so your 2200 stall may be a little light to get it off the line. You really want the car up there in the revs where the power is being made.
Again I am normally the one to say use the proper carb bigger is not always better,but I still think you may be light on the carb.

Good luck with it and dont get discouraged.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 10-16-2005, 01:22 AM
xntrik's Avatar
Save a horse, Ride a Cowboy.
 
Last photo:
Join Date: Jul 2005
Location: Arkansas
Posts: 5,131
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Here's some food for thought.

2-3 years ago, HotRod Mag or Car Craft ?, took (assoc editor) Matt King's green Nova with the 383 SBC into the mid 13s. They did an extensive article about changing rear gears and torque converters, etc.

If I remember correctly they went in 3 steps from 3.08 to 4.11, and upped the stall in 3 steps from 1800 to 3600, combining each gear with each converter.... they really did a lot of effort in two days.

The result was some improvement in times..... but... under their controlled conditions, the variations with several gears and converters was that the times varied only about .3 and the speed less than 2.0......

Proving to me what I had always thought.... Unless you have a truely dedicated drag car (high rpm screamer), the differences are certainly not worth the $$ price paid.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 10-16-2005, 06:13 AM
steve t's Avatar
ex biker, now hotrodder
 
Join Date: Mar 2005
Location: NC
Age: 64
Posts: 863
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
why cant you drive on road, 380 gears are ok on road
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 10-16-2005, 09:58 AM
Member
 
Last photo:
Join Date: Sep 2004
Location: wichita, KS
Age: 41
Posts: 126
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
In 4 years I have put maybe 3000 miles on it. as for any other changes to the engine. theres none. the timing I changed the timing every 3rd run and it really didnt change anything. I went from 0 TDC/ 6 BTC / 9 BTC to 12 BTC and my times were only a few tenths of either way. After smoking the tires in the pit I got no wheel spin, It hooked up and flew. my first run was the best and after that it continually got a little worse, my plugs were clean at the beginning and after the night was done there a little carboned but not bad. it is running a little rich maybe. as for on the road my engine is twisting 3200 at 65 MPH which sucks to drive on the highway now. its ok for the street but I dont have an overdrive its a C4. and I dont like to drive any engine for long periods of time over 3k. I am not sure what my overall timing is because I dont know what the specs on my dist is. I like my mallory unilite but tech support sucks. but basicly its the same motor and tunning as it was the last time just with a different gear and stall. on of my thoughts was that its reaching it powerban to quick and not pulling the whole way to the line in third gear. when I pass the line its running at 5000. so I thought that was where I was losing my time but it still doesnt explain my 60 foot times. arrggh
oh and according to my dyno run. my engine is making its peak power at 4800 and torque at 2600. the engine is a 1970 cleveland with the 2v heads, edelbrock performer manifold with a 600 mech secondaries and hedman headers with flowmasters.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 10-16-2005, 05:01 PM
Siggy_Freud's Avatar
Hotrodders.com Moderator
 
Last photo:
Join Date: Dec 2003
Location: Portland, Oregon
Age: 29
Posts: 2,371
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Id check full advance and see what its at and when its all in by. Its possible that over 4 years the advance springs aren't of the same spring rate and/or the weights are off a bit.
__________________
Bringing history and technology together.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 10-16-2005, 05:03 PM
xntrik's Avatar
Save a horse, Ride a Cowboy.
 
Last photo:
Join Date: Jul 2005
Location: Arkansas
Posts: 5,131
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
[QUOTE=voodoosurfer]
...4 years
...my times are almost identical. 15 flat best time
...changes to the engine. theres none.
...times were only a few tenths of either way.

...no wheel spin, It hooked up and flew.
...my first run was the best and after that it continually got a little worse,
...my plugs were clean at the beginning and after the night was done there a little carboned but not bad.

...but basicly its the same motor and tunning ,,,,,,,
...just different gear and stall.

is there something im missing. I am at a complete loss.

QUOTE]


1) All the standard temperature/pressure/humidity/wind/track variables from year to year, day to day, and hour to hour.
2) engine internal temp getting hotter for subsequent runs
3) maybe the carb is getting tired from sitting
4) brakes dragging
5) gear and stall mismatched for combination
6) see thread entry # 4, and consider your car is slower than theirs, so the variation might be less.

I bet it would be better all the way around with a 3.25 gear. That would put you at 2750 @ 65 mph.

You might pop the 3.00 back in and make a few passes to see if it pulls better with that 2500 stall.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 10-16-2005, 05:32 PM
Member
 
Last photo:
Join Date: Sep 2004
Location: wichita, KS
Age: 41
Posts: 126
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
when i first got the stall, i still ha the 3.00 gear and the thing was a complete dog, mushy starts and sluggish shifts, so I put the 3.80 in and it really woke it up (I thought). but in reallity it did nothing but make my top end slower.
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 10-16-2005, 05:39 PM
xntrik's Avatar
Save a horse, Ride a Cowboy.
 
Last photo:
Join Date: Jul 2005
Location: Arkansas
Posts: 5,131
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Quote:
Originally Posted by voodoosurfer
when i first got the stall, i still ha the 3.00 gear and the thing was a complete dog, mushy starts and sluggish shifts, so I put the 3.80 in and it really woke it up (I thought). but in reallity it did nothing but make my top end slower.
too much stall?
what is the actual stall speed?
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 10-16-2005, 05:54 PM
bracketeer's Avatar
489 Lemans
 

Last journal entry: Street Legal
Last photo:
Join Date: Dec 2004
Location: Courtenay, BC, CehNehDeh
Age: 55
Posts: 2,139
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Since you haven't specified what cam you have. The stall may actually hurting more than helping.

You said you adjusted the timing and only picked up a few tenths. A tenth on the 1/4 is ten HP. So you were able to pick up 30 HP by adjusting the timing.

Wheel spin is not something you feel. It is measured by your 60 foot time. What was your 60 ft time 4 yrs ago as opposed to your last run.

Gearing; what was your mph as opposed to your ET from 4 yrs ago. If you did not increase tire heighth when re-gearing, you may be running out of top end power before the end of the track. This would account for a low ET.

For example;
A 26" tire,3.0 gears,@129 mph, will cross the finish line at 5504 rpm.
A 26" tire,3.8 gears,@129 mph, will cross the finish line at 7000 rpm.
I doubt very much you could attain 7000 rpm at a steady pull. Thus a low ET.
Now if you change the tire heighth,
A 30" tire, 3.8 gears, @129 mph, will cross the finish line at 6250 rpm.
You can see how increasing tire heighth will affect your ET when changing gears.

What was your rpm at the finsh 4 yrs ago as opposed to this time?

A lot more info is required here.
__________________
[URL]http://members.shaw.ca/g.body.building[/URL]

Last edited by bracketeer; 10-16-2005 at 06:20 PM.
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 10-16-2005, 08:38 PM
Member
 
Last photo:
Join Date: Sep 2004
Location: wichita, KS
Age: 41
Posts: 126
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
specs
351C over .030, 2v heads
edelbrock performer manifold
mallory unilite dist w/ vac advance
roller fulcrums
roller timing chain
hedman headers into flowmasters full exhaust
edelbrock 600
C4 with shift kit
Cam specs advertised:
-----------------------------------------------
intake@cam 2800 @ valve 484 / Duration 262
Eshaust@cam 2947 @ valve 510 / Duration 272
-----------------------------------------------
cam timing @ .050 lift
opens intake (5)* atdc / exhaust 44* bbdc
closes intake 29* abdc / exhaust (10)*
Max lift Intake 107* atdc exhaust 117* btdc
Duration intake 204* / exhaust 214*

4 years
all specs above with a non-posi 3:00 rear and stock convertor ran
reaction time .196
60 ft - 2.293
660 ft - 9.753
ET - 15.073
MPH - 91.856
RPM around 4600 if I remember correctly (it was 4 years ago)haha

Current
same setup except a Locker rearend 3:80 and a 2500 stall from hughes
reaction time .1705
60 ft - 2.2448
660 ft - 9.511
ET - 14.8564
MPH - 92.98
RPM around 5000

I dont understand cam mathematics very well so I hope the info I posted is good enough. I can also scan the piece of paper if that would be better. but I will have to reboot to do that.
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 10-16-2005, 09:07 PM
lluciano77's Avatar
Short changed on common sense
 
Last photo:
Join Date: Jun 2003
Location: california
Age: 37
Posts: 3,548
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
It is all about keeping the engine in its powerband for as long as possible, and putting under just the right amount of load.
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 10-16-2005, 10:31 PM
bracketeer's Avatar
489 Lemans
 

Last journal entry: Street Legal
Last photo:
Join Date: Dec 2004
Location: Courtenay, BC, CehNehDeh
Age: 55
Posts: 2,139
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
2500 stall should work fine with that cam.
I don't know what 2v heads are so I can't say much about your combo other than; Your 60 ft and 660 ft hasn't improved alot. I would try to borrow a 650 carb for a test run.
__________________
[URL]http://members.shaw.ca/g.body.building[/URL]
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 10-16-2005, 11:25 PM
Member
 
Last photo:
Join Date: Sep 2004
Location: wichita, KS
Age: 41
Posts: 126
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
the 2Vs have a 2.04 intake valve and a 1.65 Exhaust and I believe somewhere between a 65-71cc chamber.
Reply With Quote Quick reply to this message

Recent Hotrodding Basics posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
estimated 1/4 mile time?? tirefryin_s10 Hotrodding Basics 7 10-20-2006 12:54 PM
Horsepower & Performance Formulas/Calculators edge General Rodding Tech 7 08-13-2005 06:01 AM
1/4 mile times 78 chevy truck Engine 7 07-26-2005 11:42 PM
1/8th mile to 1/4 mile conversion Ken. P. Hotrodders' Lounge 4 09-10-2004 05:25 PM
How to get 1/4 mile times from 1/8 mile. Rubberman2003 Hotrodding Basics 7 11-18-2003 11:35 PM


All times are GMT -6. The time now is 04:14 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.