93 1/4 Mile Performance Questions
Thread Starter
Intermediate
Joined: Nov 2023
Posts: 39
Likes: 3
From: WI
93 1/4 Mile Performance Questions
This weekend I took my 93 to a drag strip for the first time, was a blast but was a little slower than I expected. Wondering if I might be down on power or if y’all think this is reasonable.
I’ve read that from factory it should do a low 14sec 1/4 mile (probably set by an auto?). Mine is the ZF6 and my best of two runs was 14.2sec at 100mph. It has a few minor mods to it that made me think I should have been able to run a little faster, but let me know what you guys think. I am a rookie so the driver mod definitely was a factor, I know that… also worth mentioning it has 95k miles and was flogged most of its life.
Mods:
-LT4 heads
-Ported LT1 intake manifold
-EGR delete
-BBK 58mm throttle body
-SLP cold air intake
-Single x-pipe muffler to straight pipes back
-MSD ignition control module and vented Opti
-“Custom tuned” ECU by previous owner
I’ve read that from factory it should do a low 14sec 1/4 mile (probably set by an auto?). Mine is the ZF6 and my best of two runs was 14.2sec at 100mph. It has a few minor mods to it that made me think I should have been able to run a little faster, but let me know what you guys think. I am a rookie so the driver mod definitely was a factor, I know that… also worth mentioning it has 95k miles and was flogged most of its life.
Mods:
-LT4 heads
-Ported LT1 intake manifold
-EGR delete
-BBK 58mm throttle body
-SLP cold air intake
-Single x-pipe muffler to straight pipes back
-MSD ignition control module and vented Opti
-“Custom tuned” ECU by previous owner
Racer
Joined: Jul 2023
Posts: 256
Likes: 87
100mph trap speed is putting down pretty decent for an older street car. What rear-end ratio do you have? That and tire/ traction levels off the lights is probably more impact on the ET than engine performance. Glad you had fun tho! 
Not the 1st or last time somebody goes to the track (or dyno 😬
and comes home with a new perspective 😉 Don't get yourself bummed about it, keep having fun 👍
Not the 1st or last time somebody goes to the track (or dyno 😬 and comes home with a new perspective 😉 Don't get yourself bummed about it, keep having fun 👍
Racer
Joined: Jul 2023
Posts: 256
Likes: 87
That, and 2 runs isn't nearly enough to settle the nerves and get a good feel for the car and that track. Assuming you were even running the same lane both times, can change things. You could break into the 13's next time with nothing more than more experience and maybe a slightly cooler-air night. Just be careful, it gets addictive!! 😁
Safety Car
Joined: Apr 2016
Posts: 4,648
Likes: 1,059
From: N.E. Ohio OH
Finalist 2020 C4 of the Year - Modified
Issues that I can see that you really should investigate
Did you mean a ported LT4 intake or really a LT1 intake with LT4 heads. There will be a mismatch at the ports if so which can affect performance
The issue would be "Did prev owner get it right".
-LT4 heads
-Ported LT1 intake manifold
-Ported LT1 intake manifold
"Custom tuned” ECU by previous owner
Le Mans Master
Joined: Feb 1999
Posts: 9,938
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
My bone stock engine, no headers, but flowmaster exhaust and Lingenfelter torque convert ( which was a GM S10 truck converter), ran 13.5s all day at Rockingham dragstrip. Sticky dragstrip..
Speed was about 105mph.
1993 LT1 and I put it in D and let the transmission do its things.
Speed was about 105mph.
1993 LT1 and I put it in D and let the transmission do its things.
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Thread Starter
Intermediate
Joined: Nov 2023
Posts: 39
Likes: 3
From: WI
That, and 2 runs isn't nearly enough to settle the nerves and get a good feel for the car and that track. Assuming you were even running the same lane both times, can change things. You could break into the 13's next time with nothing more than more experience and maybe a slightly cooler-air night. Just be careful, it gets addictive!! 😁
I don't know the rear-end ratio offhand, it's just the base trim LT1 package as far as I know. Is there something in the VIN that would indicate if I have the performance axle ratio option?
Thread Starter
Intermediate
Joined: Nov 2023
Posts: 39
Likes: 3
From: WI
And the ECU was tuned by a guy named The LS Cowboy. With a name like that, I didn't question him...
Thread Starter
Intermediate
Joined: Nov 2023
Posts: 39
Likes: 3
From: WI
Track was Rock Falls Raceway in Eau Claire, WI (internet says 1000ft above sea level). Don't know the DA but the weather was decent that day.
60' was 2.2sec, still learning how much I can push this stock clutch.
Reaction time... we'll just say room for improvement
Gear ratio, unknown but it's the base trim LT1. If anyone knows a free site for getting a build sheet or can interpret the VIN for me, I'm all ears!
60' was 2.2sec, still learning how much I can push this stock clutch.
Reaction time... we'll just say room for improvement
Gear ratio, unknown but it's the base trim LT1. If anyone knows a free site for getting a build sheet or can interpret the VIN for me, I'm all ears!
Thread Starter
Intermediate
Joined: Nov 2023
Posts: 39
Likes: 3
From: WI
My bone stock engine, no headers, but flowmaster exhaust and Lingenfelter torque convert ( which was a GM S10 truck converter), ran 13.5s all day at Rockingham dragstrip. Sticky dragstrip..
Speed was about 105mph.
1993 LT1 and I put it in D and let the transmission do its things.
Speed was about 105mph.
1993 LT1 and I put it in D and let the transmission do its things.
Thread Starter
Intermediate
Joined: Nov 2023
Posts: 39
Likes: 3
From: WI
I ran a few of those online calculators that you enter your trap speed and car weight with driver in it and it kicks out an estimated HP. The results varied between 260 and 285hp at flywheel, so I suppose low 14’s tracks with your C3 experience.
Le Mans Master
Joined: Feb 1999
Posts: 9,938
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
That's awesome @steve40th ! Auto's definitely have their advantages
But sticks, they are the way to go in my opinion, as tehy have far more benefits in the whole scheme of owning a sports car
Thread Starter
Intermediate
Joined: Nov 2023
Posts: 39
Likes: 3
From: WI
They do. And unless you are willing to practice practice and pracitce some more, the sticks generally wont be as quick. Thats why GM put 2.59 and 3.08 gears in the autos for LT1 C4s. They knew if the autos had the 3.45, the sticks would be significantly slower.. Not good for sales.
But sticks, they are the way to go in my opinion, as tehy have far more benefits in the whole scheme of owning a sports car
But sticks, they are the way to go in my opinion, as tehy have far more benefits in the whole scheme of owning a sports car
Le Mans Master
Joined: Feb 1999
Posts: 9,938
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
I think Shift points are supposed to be a bit higher, 5700 rpm. Launch is a little high, but if you have traction, sounds good.
Be advised its addictive... Just learn to enjoy it.
Start buying clutch, u joints and tires. Then brake pads, front rotors, helmet, .....
Be advised its addictive... Just learn to enjoy it.
Start buying clutch, u joints and tires. Then brake pads, front rotors, helmet, .....
Le Mans Master
Joined: Feb 1999
Posts: 9,938
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
The other C4s had several gears, 3.33, 3.08, 3.45 and a 3.54 I think was offered somewhere