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top speed

J

jmp

Guest
I read somewhere (Motor Trend, 1972 article found on www.corvettearchive.com ) that the top speed of the 72 LT-1 was 152 mph... Maybe I need a driving lesson, but exactly how do you get to that speed!? At 5500 rpm, in 4th, I was going about 115mph -- I don't think I can get to 152 by the time I reach the redline!

How fast have you gotten your LT-1?
 
0

0018

Guest
jmp said:
I read somewhere (Motor Trend, 1972 article found on www.corvettearchive.com ) that the top speed of the 72 LT-1 was 152 mph... Maybe I need a driving lesson, but exactly how do you get to that speed!? At 5500 rpm, in 4th, I was going about 115mph -- I don't think I can get to 152 by the time I reach the redline!

How fast have you gotten your LT-1?
[/QUOTE

Imp, If your after topend, try the 2.73:1 Axle. The 3.08 will give you about 140 mph at 5,000 rpm. LT-1s were geared for acceleration, not top end. I had my '70 with a 3.70 ratio at 135 mph and I figured I was still alive to tell about it, so I took my foot off the gas. There was more left.
 
J

jmp

Guest
Well, I'm not really after anything -- the car is stock and going to stay that way. I was more curious than anything, 'cause the LT-1 in the article was the same as mine (3.70 gears, btw) but it seemed to have a much higher top speed.

But I really do think I need a driving lesson (I guess driving Hondas isn't the best thing for prepping for a 'vette! :s ), b/c I also have a hard time launching the thing! More practice, I guess. ;) :D
 
0

0018

Guest
JMP,
I dont know how they got a 3.70 ratio '72 LT-1 up to 150 mph. Your readings are more in line with reality, and what my '72 with 3.70s does. I know theyll do 150+ with the right highway gears. With a 75mph limit, the 3.70 is just fine. I drive a Honda too, and it takes some getting used to switching back and forth. Stu
 
J

jmp

Guest
I forgot to ask this newbie question:

What do the different ratios mean, in real-world terms? I can see how the smaller the ratio, the higher the top-end speed, but what do the higher ratios get ya'?
 
R

Robert N

Guest
If I have this right:

smaller ratios (taller gears) are better top end speed and gas mileage

higher ratios (shorter gears) are better torque and off the line acceleration.
 

F4Gary

Well-known member
Joined
Jun 5, 2002
Messages
93
Location
Grapevine,Tx
Corvette
72 LT-1 conv w/fact air
I've had mine up to 115 at Texas Motor Speedway and I was turning less than 4500 with a 3:08. I replaced the '66 4:11 rear end that was in my car when I bought it with the 3:08 for cruising purposes. The club I'm in here does alot of weekend cruises and with the 4:11 it was way too noisy.
 
Joined
May 4, 2004
Messages
405
Location
Mt. Vernon,NY,USA
Corvette
1990 Bk/Gy ZR-1, #2233
HI jmp, I had read a test report from Car and Driver,1972, that tested a '72 LT-1 w/AC and they said that they "observed a top speed of 152 mph". I think with a 3.55:1 rear and using a 6500 rpm red line on one of those speed calculator formulas you get 152 mph, but I don't remember if the formula takes into account CoF, or body drag. I know the CoF on a '72 vette is .33, same as a '72 911S.
 
Joined
Nov 8, 2002
Messages
402
Location
NH
Corvette
1972 LT-1 Coupe w/ AC
If somebody wants to do the math, my LT-1 turns approx. 3k RPMS at 80 MPH in 4th...thats with the 3.55's & Muncie M20...
 

JJS

Proud to Support the Corvette Action Center!
Joined
Feb 19, 2003
Messages
1,315
Location
Oregon
Corvette
2013 Triple Black GS, Previous cars: 1971 LT-1
TonyK's numbers are realistic

The 3K RPM's at 80 in 4th are exactly what I see in my '71 LT1.
It feels like there's at least as much (if not more) left in my car.

Last year I had mine around 100, but I was white knuckled to the steering wheel as the car was "loose" as hell. I had some alignment work done, as well as some power steering adjustments, but I haven't had it up to those speeds yet this year. I also have new wheels, and more of a stock tire (I had wides all the way around last year) so I'm looking forward to running it wide open some Saturday or Sunday morning.
 

JJS

Proud to Support the Corvette Action Center!
Joined
Feb 19, 2003
Messages
1,315
Location
Oregon
Corvette
2013 Triple Black GS, Previous cars: 1971 LT-1
3.55's with M21

Oh yeah, I have 3.55's (4.11 original...I have these gears) with an M21.
 
L

lt1srule

Guest
funny how I remember some of this stuff...

Hi, new to the group... just found it surfin the net today. I bought one of the first LT-1s in 1970. I ordered it in Dec 1969 and it was delivered to Lou Bachrodt Chevrolet in Rockford IL the first week of Feb 1970 and of course I couldn't have it till Feb 28 (the official day of release and prices). It was a low option Marlboro Maroon Convertible, saddle leather, and AMFM. Pretty sure it had the M-21 transmission. When it was ordered, we didn't know if the LT-1 option was going to be available (it was only rumored), so I ordered a 3:55 rear end thinking I'd end up with a 350-300. The 3:55 was the performance ratio for 300HP, but economy ratio for 370HP. I was 25 in 1970 and wasn't afraid to test the limits... LOL. I seem to remember redline in first was 65 MPH... second was 90... and third was 115. I remember racing a Roadrunner one day and getting up to 135 (and he was ahead of me)... and it was just about as fast as that LT-1 was gonna go. I couldn't catch him. Worst problem with that 70 was I had to run Sunoco 260 to keep it from pinging, and it needed new plugs once a week, if u wanted to get to redline. I've owned 9 Corvettes (61-73), sold Chevrolets from 71-74, and was the President of Northern Illinois Corvette Club in 1973. The last Corvette I owned was a 72 LT-1 coupe w/air, back in the early 90s. So fire away, I remember way too much :)
 

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