HOME FORUM RULES CONTACT
     
   
   

Go Back   CLASS RACER FORUM > Class Racer Forums > .90 Heads Up Class Racing Tech


Reply
 
Thread Tools Display Modes
Old 02-20-2018, 10:39 AM   #1
ac302
Junior Member
 
Join Date: Feb 2015
Posts: 8
Likes: 0
Liked 0 Times in 0 Posts
Default Mph

Running super street. Will I gain any mph going from a 4.86 rear gear to 4.30? 950 hp car trapping about 140-142ish
ac302 is offline   Reply With Quote
Old 02-20-2018, 12:13 PM   #2
Lenny5160
Senior Member
 
Lenny5160's Avatar
 
Join Date: Nov 2015
Location: Inver Grove Heights, MN
Posts: 898
Likes: 604
Liked 432 Times in 225 Posts
Default Re: Mph

Difficult to say. I would doubt it, as the car will have a more difficult time getting up to speed when it comes off the stop.
__________________
S/ST 51
S/C 53
Lenny5160 is offline   Reply With Quote
Old 02-20-2018, 01:25 PM   #3
voltdr
Senior Member
 
Join Date: Jan 2008
Location: Texas
Posts: 700
Likes: 77
Liked 87 Times in 47 Posts
Default Re: Mph

I agree with Lenny5160. Converter lockup will change dramatically, It will slip more. Maybe try the 4.56 gear.
Dan
__________________
Dan Foley
SC 4698
voltdr is offline   Reply With Quote
Old 02-20-2018, 01:35 PM   #4
ac302
Junior Member
 
Join Date: Feb 2015
Posts: 8
Likes: 0
Liked 0 Times in 0 Posts
Default Re: Mph

My thoughts too. Was getting suggestions from others that I would pick up alot but I'm not sold on it
ac302 is offline   Reply With Quote
Old 02-20-2018, 02:15 PM   #5
Keith 944
VIP Member
 
Keith 944's Avatar
 
Join Date: Feb 2006
Location: Dela-where?
Posts: 2,111
Likes: 998
Liked 1,634 Times in 516 Posts
Default Re: Mph

Rpm=mph
That’s the short version
__________________
KEITH MAYERS
2 X somebody
many X nobody

Last edited by Keith 944; 02-20-2018 at 02:17 PM.
Keith 944 is offline   Reply With Quote
Old 02-20-2018, 02:36 PM   #6
jmcarter
VIP Member
 
jmcarter's Avatar
 
Join Date: Dec 2008
Location: Richmond Hill GA (and Port Ludlow WA)
Posts: 4,133
Likes: 1,958
Liked 2,664 Times in 851 Posts
Default Re: Mph

Hear lots of good things about the APD Max Speed....seems like better way to go if you don't mind changing to a different setup. There's another thread on throttle stops which got me doing some research.
__________________
Jim Carter
2340 Super Stock
2340 SST/2340 Stock
jmcarter is offline   Reply With Quote
Old 02-21-2018, 10:45 AM   #7
Tom Goldman
VIP Member
 
Tom Goldman's Avatar
 
Join Date: Jan 2003
Location: Allentown,PA
Posts: 2,433
Likes: 770
Liked 696 Times in 201 Posts
Default Re: Mph

That is a 12% change in gear ratio . not taking into account the probable loss of converter efficiency that will occur , that's a nearly 1000 rpm drop in trap rpm.
Not to mention the loss of reaction time and loss of acceleration coming off the stop.
I'd be talking to your converter guy , maybe looking at a lower stall higher efficiency converter using the existing gear.
You didn't mention what your trap RPM is . ....Is that a concern that it's too high ?
__________________
Tom Goldman 1500 SG , 1506 STK
Tom Goldman is offline   Reply With Quote
Old 02-28-2018, 04:10 PM   #8
DB
Junior Member
 
Join Date: Jan 2007
Location: hamilton
Posts: 29
Likes: 0
Liked 0 Times in 0 Posts
Default Re: Mph

Mine did.
DB is offline   Reply With Quote
Old 06-01-2018, 03:29 PM   #9
B1Ken
Junior Member
 
Join Date: Feb 2003
Posts: 13
Likes: 0
Liked 0 Times in 0 Posts
Default Re: Mph

I'm a little confused here. What does your car weigh? 950 HP and only 142 mph? Something doesn't calculate. I had a Super Street car that went 148-150 with 875 HP.
Car weighed 3000 lbs. (67 Cuda). I used 4.56 gears and hit the finish at about 7600 rpm. Engine made peak power at 7300.
B1Ken is offline   Reply With Quote
Old 06-09-2018, 11:15 PM   #10
gnicholson
Member
 
Join Date: Sep 2011
Posts: 100
Likes: 13
Liked 4 Times in 3 Posts
Default Re: Mph

I have a 505 bbc in a 70 chevelle that made 860 on stinnets dyno a few tears ago and it only runs 137,139 best. 4.88 gear 14.5 32 tires. 3150 with me
gnicholson is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not 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

Forum Jump


All times are GMT -4. The time now is 02:24 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright © Class Racer.com. All Rights Reserved. Designated trademarks and brands are the property of their respective owners.