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I think it's important to note that comparing these two engines (LT4 and LSx) is like comparing apples to oranges. Yes, they both have 8 cylinders and similar displacements. But the LT4 is the last of the "small block" family. LSx's were designed from the ground up to be much improved. GM even refers to them as "medium displacement V8's" They are a completely new breed of engine. Even the cylinder firing order is different. Everyone knows of the remarkable flowing LSx heads, but the block itself is much departed from traditional "small block". One of the goals of the LSx was to obtain 1 HP per cubic inch of displacement. Granted the LT4 does this as well, but at a higher RPM than LSx. If anyone has some time to kill check out this link. Very informative on LS1. http://www.idavette.net/hib/ls1c.html
Really is a shame they didn't stick with the LT5. The LT5 is what happens when the engineers tell the bean counters where to stick it!
I think it's important to note that comparing these two engines (LT4 and LSx) is like comparing apples to oranges. Yes, they both have 8 cylinders and similar displacements. But the LT4 is the last of the "small block" family. LSx's were designed from the ground up to be much improved. GM even refers to them as "medium displacement V8's" They are a completely new breed of engine. Even the cylinder firing order is different. Everyone knows of the remarkable flowing LSx heads, but the block itself is much departed from traditional "small block". One of the goals of the LSx was to obtain 1 HP per cubic inch of displacement. Granted the LT4 does this as well, but at a higher RPM than LSx. If anyone has some time to kill check out this link. Very informative on LS1. http://www.idavette.net/hib/ls1c.html
Really is a shame they didn't stick with the LT5. The LT5 is what happens when the engineers tell the bean counters where to stick it!
As I stated above, the only thing in common between the SBC and the LSx motor is bore center. That's IT!!!
The LT5 is a good motor, but very complex and very heavy. A ZR1 weighed 200 lbs more than the same base coupe.
BTW, the LT5 solders on as the father of the Caddy Northstar!
As I stated above, the only thing in common between the SBC and the LSx motor is bore center. That's IT!!!
The LT5 is a good motor, but very complex and very heavy. A ZR1 weighed 200 lbs more than the same base coupe.
BTW, the LT5 solders on as the father of the Caddy Northstar!
Whoops, I meant to give bogus credit for that observation. Couldn't remember who said it off hand and was too lazy to re-read the thread. I guess bogus doesn't sleep either Wasn't the LT5 an aluminum block? Must be all that computer crap weighing it down. Who else finds themselves wanting a Caddy XLR-V when it comes out?
From: Everyday you must choose between the pain of discipline and the pain of regret. Fredericktown, OH
Originally Posted by bogus
An all new Vette was being released, and it had to be better, in all facets, than the prior version. That meant, it had to have more power than the base model it replaced. The engine was new, the drivetrain, the chassis, everything.
Absolutely, and the cost of developing the LT-4 is far less than not selling any vettes in 1996 as people waited another year for the C5.
I believe the LT-4 is a result of multiple factors, using r&d that had yet to find its way into the LT-1, sending the C4 out with a bang, filling the HP hole left by the departing LT-5, and they needs to find a way to make sure they sold vettes.
People will argue that they still sold a ton of LT-1 vettes in 1996, but would all the people who bought LT-4s have bought an LT-1 or waited?
I bought, actually leased, my LT4 because......well I wanted an LT4, and loved the stealth aspect of having a GrandSport engine in sheeps clothing.....BlackSheep that is...
Another really big reason.......In 1996 GM was selling $40K Vettes for $28K.......then they added great lease deals with the idea buyers would be back in 2 years to buy a C5.......but no C5 for me, I could not pass the buyout on the LT4!!!!! In 1997 GM was selling $40K Vette for $40K+....
From: Stafford, Virginia Kittah, Kittah, Kittah...
Originally Posted by vader86
82 was a crossfire, yes.
GM had to tool up the LT1 in its last year of production because most of the information about the C5 was already out, and they wanted to give people a reason to buy the 96s, so they bumped up the power. GM usually does this when they know people will just wait to buy the newer, improved model.
From: No more yankee my wankee, the Donger is tired!
Originally Posted by wake
Why didn't they do something for 2004 then???
They did, that Z16 POS. 82 Had the collector edition, 96 had the GS and Collector edition. 04 had the Z16. Look at how many C5's are still sitting on the lots unsold.
LT4 was done for several , aforementioned reasons:
Last year of C4s's 12 year production, no more high hp LT5, needed to sell cars even though the new C5 was coming next year, final display of Gen II production power in Vette.
LT4 produces nearly identical power and torque curves as early Ls1's. Even modified they are very close but the edge going to the LS1. LT4 was underrated by about 10-15 hp , it should have been exactly what early LS1 was , 345hp. Even GM engineers stated when the C5 arrived that it was about the same overall performance as the 1996 LT4 it replaced on paper, the difference was in the feel.
What is kind of amazing is that had the LTx engines been aluminum blocks , those C4's would be as light as LSx cars (though not nearly as stiff).
Whoops, I meant to give bogus credit for that observation. Couldn't remember who said it off hand and was too lazy to re-read the thread. I guess bogus doesn't sleep either Wasn't the LT5 an aluminum block? Must be all that computer crap weighing it down. Who else finds themselves wanting a Caddy XLR-V when it comes out?
If I remember the build of the LT5 correctly, it's an aluminum block and heads, with steel cylinder liners.
What made is so heavy was the heads and complex intake system. The steel liners ain't much...
Not sure why they choose to change the lt1 some. I know a coupe guys with lt4's and I have driven them and not noticed that power difference from my 95 lt1(lt4 only pulls a little harder from 5800 rpm and on...theres not much left after 5800) I have even beaten these lt4 they have at the track many times so I really don't see how people say they have more than 330hp. Also these guys have had some problems with theirs, seems like they took a solid platform and slapped a few upgrades on it at the last minute to me so not a lt4 fan and not sure why GM went this route.
I THINK they shoulda put the lt5 in the cars not upgraded the lt1.....that woulda been something to sell the 96's for sure!
also the lt4 had the same torque as a lt1......340lbs...nto 350 like someone mentioned.
Last edited by wildman378; Jan 19, 2005 at 09:56 PM.