LT1 vs LT4
Thread Starter
Melting Slicks
Joined: Dec 2001
Posts: 2,437
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From: Gainesville Fl
LT1 vs LT4
is there much bottom end difference in these two? or should the power band be about the same down low? i drove a buddys stock LT1 tonight and his seems to rev and pull a little bit better than mine down low. his will rev up to 3k with just a touch of the gas pedal and throws you back in ur seat a little more and i remind you its 100% stock. i have a few mods but i am thinking that since i know my car is getting air and i just replaced the fuel pump and the fuel injectors are good and im getting good fuel pressure it has to be the spark. its the orignala optispark and i dont ever know if the plugs and wires have ever been changed. it has 160k miles on it so im wondering if im not getting enough spark to get the power i want untill it has already reveed up and that stock LT4 cam can really spin and generate power. what do you all think?
Race Director
Joined: Dec 2002
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From: SCMR Rat Pack'r Charter Member..Great Bend KS
Interesting question.
When Car & Driver tested the LT4 in 1996, they turned the same quarter mile time as the last LT1/MN6 they tested. (in 1993, IIRC)
My opinion is that from idle to the LT1's redline, the engines are pretty much equal. The advantage for the LT4 is that last 500rpm pull.
Maybe your LT4 feels weaker than a stock LT1 because of the LT4's "mods".
Hey, it wouldn't be the first time.....
BTW, "quality" or strength of spark has no influence on power output. If the existing spark ignites the mixture at the right time, that's all it can do. Also, don't put too much stock in the buttdyno. Very few are that accurate....
Unless you have a real dyno on which to compare the two cars, the best way to compare them is a 30-130mph, side-by-side pull in third gear...and even that will be influenced (as will the buttdyno) by rearend gearing.
The bottom line: the LT4 does make more power than the LT1, but not much and only very near the redline.
Larry
code5coupe
When Car & Driver tested the LT4 in 1996, they turned the same quarter mile time as the last LT1/MN6 they tested. (in 1993, IIRC)
My opinion is that from idle to the LT1's redline, the engines are pretty much equal. The advantage for the LT4 is that last 500rpm pull.
Maybe your LT4 feels weaker than a stock LT1 because of the LT4's "mods".
Hey, it wouldn't be the first time.....
BTW, "quality" or strength of spark has no influence on power output. If the existing spark ignites the mixture at the right time, that's all it can do. Also, don't put too much stock in the buttdyno. Very few are that accurate....
Unless you have a real dyno on which to compare the two cars, the best way to compare them is a 30-130mph, side-by-side pull in third gear...and even that will be influenced (as will the buttdyno) by rearend gearing.
The bottom line: the LT4 does make more power than the LT1, but not much and only very near the redline.
Larry
code5coupe
Last edited by rocco16; Jul 29, 2005 at 10:34 AM.
Thread Starter
Melting Slicks
Joined: Dec 2001
Posts: 2,437
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From: Gainesville Fl
hmmm well most of my mods are done for topend power and its possible i have lost a little bit of bottom end torque i suppose. I wonder if a new ignition system will help me at all. i have heard ppl say that as the opti gets ready to die it WILL subtract horsepower. i guess those questions will be somewhat answered next when i do a complete tune up and cam swap
Burning Brakes
Joined: Nov 2004
Posts: 834
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From: Keller Texas
Originally Posted by 1996man
hmmm well most of my mods are done for topend power and its possible i have lost a little bit of bottom end torque i suppose. I wonder if a new ignition system will help me at all. i have heard ppl say that as the opti gets ready to die it WILL subtract horsepower. i guess those questions will be somewhat answered next when i do a complete tune up and cam swap
Well let me tell you it does make a differance in the spark because of several different reasons.....I would check to see if the plug wires have been changed because I have a LT4 and I looked at the plug wires at night in the dark and it looked like a light show.....The wires break down over time and you will still get fire at the plugs but it may not be the correct amount of fire and that will cause the fuel not to burn commpletly and you will not get the full power out of the fuel that is burned! My LT4 had 110k miles with the original opti as well. I have changed wires and the opti and it made a big difference. If you cant burn "all" of the fuel then you will be down on power.
Large Impressive Member
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
With 160K miles it could have any of a number of issues that are affecting your off idle response.
Racer
Joined: Apr 2003
Posts: 286
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From: Suffolk VA
Originally Posted by rocco16
BTW, "quality" or strength of spark has no influence on power output. If the existing spark ignites the mixture at the right time, that's all it can do
WTH??? Spark Strength has no influence on power output??? Well I guess I have been wasting my time and money on all those Malory, Jacobs, MSD and Accel ignition systems with the "hotter coils" ... Man what a conspiracy this must be, all those aftermarket companies selling stuff that has no influence on an engines power output..
Of course ignition strength has an influence on power... weaker sparks won't ignite all of the mix and thus not produce as much power.
Melting Slicks
Joined: Apr 2003
Posts: 2,150
Likes: 6
From: NS
Originally Posted by KyRP2NITe Corvette
Of course ignition strength has an influence on power... weaker sparks won't ignite all of the mix and thus not produce as much power.
So, if you engine is working fine and not misfiring, putting a high output coil isn't going to do squat for you. Put our stock ignition systems on a race engine with 13:1 compression and 8500rpm red line and it'll misfire like a SOB.
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Safety Car
Joined: Feb 2000
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From: MANDEVILLE, LA La
Originally Posted by Corvette Kid NC
With 160K miles it could have any of a number of issues that are affecting your off idle response.
Le Mans Master
Joined: Apr 2000
Posts: 5,713
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From: Manassas VA
I have 2 thoughts on this. 1. are both cars 6sp.? Because if not that can make a difference. 2. Muffler eliminators are known to make a LT1-4 vette loose power. Just ask Mr. Mojo. He has posted before on his experience of removing mufflers.
Safety Car
Joined: Sep 2000
Posts: 3,524
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From: Hinckley Ohio
Originally Posted by 1996man
i dont ever know if the plugs and wires have ever been changed. it has 160k miles ?
Plus the original LT4 plugs are known for loosing the platinum "hocky" pucks.....
Does your buddy's LT1 have a 160K miles on it........
BTW LT1 & LT4 are very close in engine torque below 4000 rpm, but LT4's torque stays up while LT1's falls off........if you are racing you want to shift the LT4 right at redline and all things being equal it will beat the LT1 easily........
Burning Brakes
Joined: Feb 2000
Posts: 1,247
Likes: 2
From: Parker, Colorado, USofA
Originally Posted by KyRP2NITe Corvette
WTH??? Spark Strength has no influence on power output??? Well I guess I have been wasting my time and money on all those Malory, Jacobs, MSD and Accel ignition systems with the "hotter coils" ... Man what a conspiracy this must be, all those aftermarket companies selling stuff that has no influence on an engines power output..
Of course ignition strength has an influence on power... weaker sparks won't ignite all of the mix and thus not produce as much power.
Use your uprated ignition stuff to replace old parts, control redline, whatever, but I _seriously_ doubt if you've got a mild to stock motor that it's making ANY difference.
Race Director
Joined: Jan 2005
Posts: 10,641
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From: Slidell Louisiana
He said that most of his mods were for top-end power. There is no free lunch, for example if you hog out the ports to increase your top end you lose a little low end grunt. The LT1 and LT4 torque ratings are pretty close so his buddy can have (like Mr Mojo's) an exceptional LT1 and the LT4 may be one the is at the bottom of the statistical bell curve. The gearing, tires, amount of gas, etc may be different and SOTP dynos are notoriously inacurrate. So nothing may be the matter.
Burning Brakes
Joined: Mar 2005
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heres some numbers for you
95 LT1 6spd
rearwheel horsepower 265
rearwheel torque 295
0-60 4.9
1/4 mile 13.3@104
96 LT4 6spd
rearwheel horsepower 300
rearwheel torque 305
0-60 4.7
1/4 mile 12.9@108
those are "best average numbers,any better than those,and they are factory freaks IE Mojo
of course,they could be worse,depending on production tolerances etc.both cars are pretty even up to about the 1/8 mile,then,The LT4 pulls away.BTW,the LT4's I've driven felt like they had a tiny bit better throttle response.
95 LT1 6spd
rearwheel horsepower 265
rearwheel torque 295
0-60 4.9
1/4 mile 13.3@104
96 LT4 6spd
rearwheel horsepower 300
rearwheel torque 305
0-60 4.7
1/4 mile 12.9@108
those are "best average numbers,any better than those,and they are factory freaks IE Mojo
of course,they could be worse,depending on production tolerances etc.both cars are pretty even up to about the 1/8 mile,then,The LT4 pulls away.BTW,the LT4's I've driven felt like they had a tiny bit better throttle response.
Melting Slicks
Joined: Mar 2003
Posts: 2,472
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From: Toronto ONTARIO
Honest opinion? 160 k miles... could be many things ( as was said above).
Engine wear is my first opinion. that puppy needs refreshening. Not putting down Lt1s but an LT1 should NOT feel stronger than your car especially if yours has mods.
Engine wear is my first opinion. that puppy needs refreshening. Not putting down Lt1s but an LT1 should NOT feel stronger than your car especially if yours has mods.
Race Director
Joined: Oct 2000
Posts: 14,064
Likes: 1,166
From: N. Alabama
In all honesty, let me relate my experience a couple of weeks ago at the Nashville speedway road course; I carried my '03 Z w/ only air intake mod. I ran decent times on my street Firestone wide ovals. A friend in his 4K mile C6 ran right with me and I had to actually let him pass toward the end of the day. I was tuckered and he was more aggressive and more familiar with the track. We were right together on the backstretch at 125 to 130 mph.
A stock Z28 passed us both. The Z28 gave up just a little on the backstretch but got us both in the road course. The Z28 had 1 1/2" torsion bar, slicks, and upgraded brakes.
Bottom line; one is not going to tell a whole lot of difference in stock trim and with street tires/alignment between LT1, LT4, LS6 and LS2 in real world. Fractions of a second are just that; fractions of a second!
Upgrades make all the difference in the world.
A stock Z28 passed us both. The Z28 gave up just a little on the backstretch but got us both in the road course. The Z28 had 1 1/2" torsion bar, slicks, and upgraded brakes.
Bottom line; one is not going to tell a whole lot of difference in stock trim and with street tires/alignment between LT1, LT4, LS6 and LS2 in real world. Fractions of a second are just that; fractions of a second!
Upgrades make all the difference in the world.
Thread Starter
Melting Slicks
Joined: Dec 2001
Posts: 2,437
Likes: 1
From: Gainesville Fl
i think after reading everything it is a combination of my spark plugs, wires and opti being old plus i think i lost a little bottom end tq when i made those exhaust mods to get over 110 trap speed in the quarter mile. To answer some of the questions asked.... yes it was a 6 speed as well 92 with 120k miles on it. not sure about the other options. but i do think he has had it tuned up pretty recently which is something i desperatly need to do
