Need some LT4 Tech Info, Plz
Thread Starter
Instructor
Joined: Mar 2005
Posts: 157
Likes: 2
From: Fayetteville Ga
Need some LT4 Tech Info, Plz
1. Does the LT4 require premium gas? Is the gas mileage the same
as LT-1?
2. What is the rear axle ratio for LT4 equipped Vettes?
3. Any special quirks with the LT4, cronic problems, things to watch
out for when buying a used one? That kind of thing.
as LT-1?
2. What is the rear axle ratio for LT4 equipped Vettes?
3. Any special quirks with the LT4, cronic problems, things to watch
out for when buying a used one? That kind of thing.
Drifting
Joined: May 2005
Posts: 1,336
Likes: 12
From: Chicago Executive Airport, formerly known as Palwaukee
No-IL Events Coordinator
St. Jude Donor '12-'13-'14-'15-'16-'17
LT4 requires same gasoline as LT1: Premium.
Rear axle ratio: 3.45 to 1
Drive the Vette. If it screams, you have a good one.
Actually, all the LT4s scream!
Rear axle ratio: 3.45 to 1
Drive the Vette. If it screams, you have a good one.
Actually, all the LT4s scream!
Heel & Toe
Joined: May 2002
Posts: 20
Likes: 0
From: Waco Tx
Your gas milage is going to depend on how you drive.
I have gotten up to 28 mpg on the hiway driving like there is an egg under foot on the gas pedal. Of course, that's no fun!
The LT4 is an awsome motor and even driven like they want to be, will still reward you with decent economy.
I have gotten up to 28 mpg on the hiway driving like there is an egg under foot on the gas pedal. Of course, that's no fun!
The LT4 is an awsome motor and even driven like they want to be, will still reward you with decent economy.
Burning Brakes
Joined: Apr 2001
Posts: 994
Likes: 0
From: Jamison PA
Originally Posted by jonecap
I've gotten 26mpg on the highway with 4.10s if I drive very conservatively. Great motors!
I've got 4.11's gears in and get 26-27 on the highway. Best quirk is the engine wants to scream up to redline in every gear.
Safety Car
Joined: Apr 2003
Posts: 3,793
Likes: 9
From: VA
Originally Posted by TorchRedlt4man
LT4 requires same gasoline as LT1: Premium.
Also, the definition of "premium" in the manual is 91, which is mid-grade in many parts of the country.
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Safety Car
Joined: Apr 2003
Posts: 3,793
Likes: 9
From: VA
Originally Posted by Flyingboy
1. Does the LT4 require premium gas? Is the gas mileage the same
as LT-1?
2. What is the rear axle ratio for LT4 equipped Vettes?
3. Any special quirks with the LT4, cronic problems, things to watch
out for when buying a used one? That kind of thing.
as LT-1?
2. What is the rear axle ratio for LT4 equipped Vettes?
3. Any special quirks with the LT4, cronic problems, things to watch
out for when buying a used one? That kind of thing.
Drifting
Joined: Mar 2004
Posts: 1,522
Likes: 0
The LT4 DOES require premium. That doesn't mean that it won't run on anything less, but the computer will cut timing, at a loss of power and fuel economy!
I remember a post on here from (Mr. Mojo I believe it was) about how he was in a cruise with some other c4's, and on guy had used less than premium gas, and got a noticeable drop in his fuel economy versus other cars like his running the exact same route together.
IMO: there is no reason at all to run less than premium gas in a LT4, or really a LT1. An older vette with a lower compression ratio, or a vette that has been rebuilt and has less compression, sure, but not a stock one. We are talking 20 cents a gallon and 20 gallons, equals a whopping $4.00. You bought a vette, not a yugo. Just because you can get away with it, doesn't make it a good idea.
I remember a post on here from (Mr. Mojo I believe it was) about how he was in a cruise with some other c4's, and on guy had used less than premium gas, and got a noticeable drop in his fuel economy versus other cars like his running the exact same route together.
IMO: there is no reason at all to run less than premium gas in a LT4, or really a LT1. An older vette with a lower compression ratio, or a vette that has been rebuilt and has less compression, sure, but not a stock one. We are talking 20 cents a gallon and 20 gallons, equals a whopping $4.00. You bought a vette, not a yugo. Just because you can get away with it, doesn't make it a good idea.
Race Director
Joined: Jan 2002
Posts: 12,263
Likes: 86
From: O'Fallon Missouri
Originally Posted by Vis Croceus
The LT1 does not require premium, it just wants it. I would assume the LT4 is the same. I doubt GM makes any vehicles that require premium.
Also, the definition of "premium" in the manual is 91, which is mid-grade in many parts of the country.
Also, the definition of "premium" in the manual is 91, which is mid-grade in many parts of the country.
"Use premium unleaded fuel rated at 91 octane or higher. You may use middle grade or regular unleaded gasolines, but your vehicle may not accellerate as well".
I datalogged a friends 94 LT1 using regular (87 octane) unleaded, and it was under a constant spark retard.
Premium unleaded is recommended, but not required.
Drifting
Joined: May 2005
Posts: 1,370
Likes: 1
From: Raleigh NC
Originally Posted by Tony.96LT4
Best quirk is the engine wants to scream up to redline in every gear.
LT4's just beg for more RPM...they will scream. I turn mine to 6,500 at the track (rev limiter has been raised). The '90 L98 I previously had didn't want to turn much at all...but it did have some torque.
Instructor
Joined: Dec 2004
Posts: 168
Likes: 0
From: Charlottesville VA
Just my take, but I don't know if gas mileage would be one of my primary concerns when looking to buy a Corvette. Reason being, that you probably will rarely get anywhere close to those high MPG numbers, since getting on the gas in a LT4 is to much fun to resist. Of course if you are going to daily drive it, then that might be more of an issue I suppose. Running less than premium though should immediately get the driver brought up on "Corvette Neglect and Abuse" charges.
Safety Car
Joined: Sep 2000
Posts: 3,524
Likes: 4
From: Hinckley Ohio
Originally Posted by Flyingboy
Ok, with the 3.45:1 rear axle ratio. What kind of gas mileage does the LT4 platform get? High/ low,,,average
It is an incredible engine......you can loaf along easily it 6th gear at barely 1000rpm or you can easily run to redline.......and 6th gear is very useable due to the tremendous versatility of the LT4 engine...
Does great around town, if you keep your foot out of it....I don't ever recall getting anything less than 20mpg between fillups..
You will love it.....a great economy car..
Thread Starter
Instructor
Joined: Mar 2005
Posts: 157
Likes: 2
From: Fayetteville Ga
Thanks for all the input guys. I agree, and will run premium in the car (when I get it). The extra $$ isn't much. And my daily driving distance will only put 10k on it per year. Buying a vette of this year/ price means not to get skimpy on fuel quality. I show my Vettes more respect than that 
I was just curious.
I was just curious.
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
I am facinated... everyone is giving credit to the motor for the great MPG, but are forgetting the real reason it's so good - GM engine management systems are truely world class.
THAT'S why the LTx engines get mid-20s to low-30s hiway.
1992-1993 LT1s were batch injected, and the best highway MPG I ever got was in the 26mpg range. When sequential came out in 1994, the mileage JUMPED - 31~33MPG from what I have read here.
The LS1 is even better...
And it's all because of the engine management systems.
THAT'S why the LTx engines get mid-20s to low-30s hiway.
1992-1993 LT1s were batch injected, and the best highway MPG I ever got was in the 26mpg range. When sequential came out in 1994, the mileage JUMPED - 31~33MPG from what I have read here.
The LS1 is even better...
And it's all because of the engine management systems.
Drifting
Joined: May 2005
Posts: 1,336
Likes: 12
From: Chicago Executive Airport, formerly known as Palwaukee
No-IL Events Coordinator
St. Jude Donor '12-'13-'14-'15-'16-'17
My LT4 gives me up to 31mpg on the highway at a steady 75mph. I usually do not use 6th gear unless I am doing at least 75.
Racer
Joined: Apr 2005
Posts: 408
Likes: 0
Originally Posted by bogus
I am facinated... everyone is giving credit to the motor for the great MPG, but are forgetting the real reason it's so good - GM engine management systems are truely world class.
THAT'S why the LTx engines get mid-20s to low-30s hiway.
1992-1993 LT1s were batch injected, and the best highway MPG I ever got was in the 26mpg range. When sequential came out in 1994, the mileage JUMPED - 31~33MPG from what I have read here.
The LS1 is even better...
And it's all because of the engine management systems.
THAT'S why the LTx engines get mid-20s to low-30s hiway.
1992-1993 LT1s were batch injected, and the best highway MPG I ever got was in the 26mpg range. When sequential came out in 1994, the mileage JUMPED - 31~33MPG from what I have read here.
The LS1 is even better...
And it's all because of the engine management systems.
Safety Car
Joined: Sep 2006
Posts: 4,129
Likes: 1
From: Pasadena CA
I drive 50 miles a day with a mix of freeway and streets - much of the freeway is stop-go and variable speeds. I step on the gas where I know I can 
Getting about 19.6 mpg per tank and had it just about 2 weeks now. I use 6th at 50 mph+ when cruising
Getting about 19.6 mpg per tank and had it just about 2 weeks now. I use 6th at 50 mph+ when cruising
Last edited by Eakster; Oct 16, 2006 at 11:52 PM.