LT1 vs LT4 pros and cons?
Racer
Joined: Mar 2018
Posts: 411
Likes: 97
From: Las Vegas
thanks for the chart. I see the LT4 weighs about 200lbs more. Compression ratio is .5 higher and peak torque happens 500rpm higher and I wonder how much hp it makes at 5000 rpm, I wonder if less that LT1. Peak horsepower is greater at 330 but at almost 1000 rpm higher for only 30hp gain. Roller rockers, stronger timing gears, both run on premium gas 93 so thats no different. Is it really worth it Im wondering and it was only made the one year. Are there parts that would be impossible to find whereas the LT1 is everywhere? What do you all advise?
Last edited by jayjones; Nov 18, 2019 at 06:54 AM.
Safety Car
Joined: Apr 2016
Posts: 4,648
Likes: 1,059
From: N.E. Ohio OH
Finalist 2020 C4 of the Year - Modified
There is no way the lt4 weighs 200 pounds more. Yes, I see the link says so. But how that is logical, is beyond me.
There is no component that differs between the 2 that can add 200 lbs.
Are there parts that would be impossible to find whereas the LT1 is everywhere? What do you all advise?
Le Mans Master
Joined: Aug 2015
Posts: 6,102
Likes: 1,981
From: St. Charles MO
Originally Posted by garack
Compression ratio is .5 higher and peak torque happens 500rpm higher and I wonder how much hp it makes at 5000 rpm, I wonder if less that LT1. Peak horsepower is greater at 330 but at almost 1000 rpm higher for only 30hp gain.
Well...yeah, that's how power is generally made from the same displacement. And power is the sole determinant of which car is faster in a straight line. Period. The LT4 has 10% more power than the LT1, and a wider rpm range as well. If they had equipped the car with a 3.73 rear gear (so that redlines occur at about the same road speed), you'd feel that extra power directly. As it is, the car is longer-legged than an LT1 since it can hold any gear to a higher road speed and keep accelerating in that lower gear after the LT1 car had to shift. You'll drive right by an LT1 car. This is not just on-paper power. It's meaningful.
The LT4 also has higher compression to make up for the slightly longer intake duration and overlap, so it won't lose anything in the midrange. At any rpm that matters at all, it's either equal to or more powerful than the LT1. You have more flexibility of when/where to shift it. The one stock LT4 C4 I've driven was just lovely to drive on the street or in competition. It's just a better engine all around.
Thread Starter
Burning Brakes
Joined: Oct 2019
Posts: 1,110
Likes: 119
From: USA
Yeah, the goofey chart has been around for years. It seems that they include the weight of the transmission and the dual-mass flywheel (which alone is 40 lbs) for the LT4, but they weighed the LT1 alone. Or something. The reality is that either engine weighs around 520-530 lbs by itself. I don't know where those weights came from. If anything, the LT4 is a few ounces lighter because it doesn't have an EGR system.
Well...yeah, that's how power is generally made from the same displacement. And power is the sole determinant of which car is faster in a straight line. Period. The LT4 has 10% more power than the LT1, and a wider rpm range as well. If they had equipped the car with a 3.73 rear gear (so that redlines occur at about the same road speed), you'd feel that extra power directly. As it is, the car is longer-legged than an LT1 since it can hold any gear to a higher road speed and keep accelerating in that lower gear after the LT1 car had to shift. You'll drive right by an LT1 car. This is not just on-paper power. It's meaningful.
The LT4 also has higher compression to make up for the slightly longer intake duration and overlap, so it won't lose anything in the midrange. At any rpm that matters at all, it's either equal to or more powerful than the LT1. You have more flexibility of when/where to shift it. The one stock LT4 C4 I've driven was just lovely to drive on the street or in competition. It's just a better engine all around.
Well...yeah, that's how power is generally made from the same displacement. And power is the sole determinant of which car is faster in a straight line. Period. The LT4 has 10% more power than the LT1, and a wider rpm range as well. If they had equipped the car with a 3.73 rear gear (so that redlines occur at about the same road speed), you'd feel that extra power directly. As it is, the car is longer-legged than an LT1 since it can hold any gear to a higher road speed and keep accelerating in that lower gear after the LT1 car had to shift. You'll drive right by an LT1 car. This is not just on-paper power. It's meaningful.
The LT4 also has higher compression to make up for the slightly longer intake duration and overlap, so it won't lose anything in the midrange. At any rpm that matters at all, it's either equal to or more powerful than the LT1. You have more flexibility of when/where to shift it. The one stock LT4 C4 I've driven was just lovely to drive on the street or in competition. It's just a better engine all around.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
Reworked? Haha. If you rework the LS like they did the LT4’s they will easily blow that time away. Just one turbo on an LS engine would destroy that time slip. LS engines are still king when it comes to horsepower. My 98 Z will stomp my two low mileage C4 cars. All three are completely stock. My wife’s GMC Yukon Denali XL comes close to beating my C4 cars. The 6.2 LS engine is a beast of a motor. I am a former racer so I know how to drive a car and all we do is a straight line shot and she can get het beast moving. Crazy how awesome the LS platform is. LT1/4 are good engines but an LS they are not.
Racer
Joined: Mar 2018
Posts: 411
Likes: 97
From: Las Vegas
You're usually more accurate than this...OP was talking about peak engine horsepower which isn't the sole determinant of which car is faster in a straight line. I'm actually not disagreeing with your statement since I know you were referring to "tractive force per unit time" (isn't that what you've called it in the past?) but your reply may be misleading to some
Le Mans Master
Joined: Aug 2015
Posts: 6,102
Likes: 1,981
From: St. Charles MO
You're usually more accurate than this...OP was talking about peak engine horsepower which isn't the sole determinant of which car is faster in a straight line. I'm actually not disagreeing with your statement since I know you were referring to "tractive force per unit time" (isn't that what you've called it in the past?) but your reply may be misleading to some
So actually I was referring to average power during a run through the gears, not just peak power. It is useful to point this out more clearly, though. The OP needs to know that the LT4 isn't just more powerful at one specific rpm. I had alluded to that, but didn't explicitly say it.
Last edited by MatthewMiller; Nov 18, 2019 at 12:47 PM.
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Melting Slicks
Joined: Jul 2002
Posts: 2,223
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From: Tallahassee fl
I highly suggest driving both LT1 and LT4 cars. The power isn't just when hammering it... the power the LT4 makes can be felt driving the car to the end of the road just cruising. It's impossible to explain without just feeling it for yourself. The LT4 feels like the L98 down low... where all the torque makes it a fun daily driver / stoplight to stoplight car without having the massive falloff up top... they just want to keep revving to the moon, and they do so better than the LT1.
Thread Starter
Burning Brakes
Joined: Oct 2019
Posts: 1,110
Likes: 119
From: USA
I highly suggest driving both LT1 and LT4 cars. The power isn't just when hammering it... the power the LT4 makes can be felt driving the car to the end of the road just cruising. It's impossible to explain without just feeling it for yourself. The LT4 feels like the L98 down low... where all the torque makes it a fun daily driver / stoplight to stoplight car without having the massive falloff up top... they just want to keep revving to the moon, and they do so better than the LT1.
Race Director
Joined: Sep 2001
Posts: 14,676
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From: NEwhere Ohio
Le Mans Master
Joined: Aug 2015
Posts: 6,102
Likes: 1,981
From: St. Charles MO
ultimately this is what I wanted to know. Thank you vette. Looking at the specs I was getting the impression that it was a high revving engine that was better for racing but not as good down low as the LT1 and that to really see any positive difference I would have to go over 5000 rpms which is not how I typically drive around town.
Last edited by MatthewMiller; Nov 18, 2019 at 05:12 PM.
Thread Starter
Burning Brakes
Joined: Oct 2019
Posts: 1,110
Likes: 119
From: USA
Le Mans Master
Joined: Aug 2015
Posts: 6,102
Likes: 1,981
From: St. Charles MO
In stock form, it has a solenoid that forces a 1-4 shift unless you're over a certain percent throttle or certain mph. All LT1 and LT4 have it, I believe, as do C5s. It was a way to get an improved EPA fuel mileage rating. And it's horrific. Luckily, it is easy and cheap to bypass with a resistor kit (I think) or to disable it in the PCM if you have programming software (Jet DST software suite in the case of a 1996).
Thread Starter
Burning Brakes
Joined: Oct 2019
Posts: 1,110
Likes: 119
From: USA
In stock form, it has a solenoid that forces a 1-4 shift unless you're over a certain percent throttle or certain mph. All LT1 and LT4 have it, I believe, as do C5s. It was a way to get an improved EPA fuel mileage rating. And it's horrific. Luckily, it is easy and cheap to bypass with a resistor kit (I think) or to disable it in the PCM if you have programming software (Jet DST software suite in the case of a 1996).
Thread Starter
Burning Brakes
Joined: Oct 2019
Posts: 1,110
Likes: 119
From: USA
so I dont need to hold out for the LT4? I found a 94 with the LT1 80k miles. maybe I should just get that one?
Last edited by Garack; Nov 21, 2019 at 04:30 PM.
