top end speed
Thread Starter
8th Gear
Joined: Apr 2012
Posts: 8
Likes: 0
top end speed
I have a 79 vette L82 with 350 cu in motor and three speed automatic transmission. I time triled it Saturday and was very disapointed down the straight away. I maxed out at 110 mph at the red line 6,000 RPM's and had to lift half yway down the straight away.
Is this all I can get out of this three speed transmission?
Dick
Is this all I can get out of this three speed transmission?
Dick
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
I used a gear ratio calc. and depending on tire size you might have a 3.73 rear end.
You can change rear end gear or tire diameter, but then you might not have enough power to go any faster.
You can change rear end gear or tire diameter, but then you might not have enough power to go any faster.
Le Mans Master
Joined: Jul 2006
Posts: 8,117
Likes: 104
From: charlotte north carolina
i don't think he meant 110 for 1/4 mile. i think he means 110 is his top speed down some road.
but with errors in the speedo and tach readings, who knows how fast he was going.
personally, i think he's lucky to still be alive and able to post this after his trial run.
but with errors in the speedo and tach readings, who knows how fast he was going.
personally, i think he's lucky to still be alive and able to post this after his trial run.
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Team Owner
Joined: Jan 2006
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From: Crossville TN
Yes. That's the max speed you will get from your car with the way it is set up. You will need different rear gear or an overdrive transmission to get more top end speed.
But, unless you have a "death wish", I would advise you not to attempt a higher top end speed, unless you have tires that are rated for more speed and a car/engine that is mechanically sound for such endeavors.
But, unless you have a "death wish", I would advise you not to attempt a higher top end speed, unless you have tires that are rated for more speed and a car/engine that is mechanically sound for such endeavors.
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Actually I'm happy that a C-3 is trying out there on track days
3.73 is a good gear ratio if you have a manual tranny with OD. I drove my 79 with 4.11 rear end and OD transmissions for 20 years
That is why I keep my speeds down to about 175 mph. I'd hate to wreck at 200 mph and hurt the car
3.73 is a good gear ratio if you have a manual tranny with OD. I drove my 79 with 4.11 rear end and OD transmissions for 20 years
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
I made a top speed run this past sat night(which is only slightly passed a 1/4 mile for me). At 6190rpm I was at 137mph (gps) and it was pretty much done...it may have another 2-3mph in it but I could feel valve float getting close so I backed out. This is with 3.36 gears, T400 and 28" tires. Also I have a 10" converter that is pretty tight but it's probably still costing me 100-200rpm at real high speeds...
Car was stable as can be... I'd have no problems pushing the car to 150+ on the stock suspension if the motor/gearing would get me there..
It hit 137 mph it about 3/8 of a mile...
Car was stable as can be... I'd have no problems pushing the car to 150+ on the stock suspension if the motor/gearing would get me there..
It hit 137 mph it about 3/8 of a mile...
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
I have a 79 vette L82 with 350 cu in motor and three speed automatic transmission. I time triled it Saturday and was very disapointed down the straight away. I maxed out at 110 mph at the red line 6,000 RPM's and had to lift half yway down the straight away.
Is this all I can get out of this three speed transmission?
Dick
Is this all I can get out of this three speed transmission?
Dick
Keep the shiny side up!
Scott
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Mine hit 120mph in 3rd gear with 2 more gears to go 
and it felt like I could drive it with one finger, very stable that's why I went for the '80 with the integrated spoilers front and back
and it felt like I could drive it with one finger, very stable that's why I went for the '80 with the integrated spoilers front and back
Intermediate
Joined: Mar 2012
Posts: 38
Likes: 0
From: Broussard La
I wouldn't get on the guy for going 110mph...Heck I remember back in the day hitting 140 on a backstretch of Hwy and Boy what a feeling! LoL WAS IT SAFE? By no means...But thats what drag racers live (And Die) for and to each his own. At least he is Smart enough to take it to the track instead of the old backroad scenario. I'd change the Tranny if you are looking for more Top end speed but if your looking for 1/4 mile or 1/8 miles times id go with a Gear change.
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
I wouldn't get on the guy for going 110mph...Heck I remember back in the day hitting 140 on a backstretch of Hwy and Boy what a feeling! LoL WAS IT SAFE? By no means...But thats what drag racers live (And Die) for and to each his own. At least he is Smart enough to take it to the track instead of the old backroad scenario. I'd change the Tranny if you are looking for more Top end speed but if your looking for 1/4 mile or 1/8 miles times id go with a Gear change.
Keep the shiny side up!
Scott
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
MY '~76 tach is electronic and is a liar at 5000 rpm it's ~400 rpm too high....proven electronically with a generator and scope....
with the speedo, I believe the GPS, the gears I HAD in the car said it was correct, but that was so much BS....
the speedo is now correct to, 70 mph, dead nutz on....at 80 indicated, it's only really 78 at 100 indicated, it's only really 94 mph....
does that tell you something about the way things were designed??
Thread Starter
8th Gear
Joined: Apr 2012
Posts: 8
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I was on a track ( Lime Rock Park in CT). with Eastern Motorsport Racing Association a club I run with. I don't speed on the highways
Thread Starter
8th Gear
Joined: Apr 2012
Posts: 8
Likes: 0
Thanks, I think I will get the external tach and dwell meter out and check the accuarcy of internal tach. Don't want to hurt motor