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LS1 vs LT1


BeyondAddiction
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alright, i keep going back and forth between wanting to get an LT1 or an LS1 for my RX7, what i know:

 

LS1

Pros:

lighter

more HP right out of the box

newer with better technology

more reliable (in consideration of the opti spark)

lots more developement still being done to mod

 

Cons:

wider

more $$$ for just a stock engine

more $$$ for parts and mods

aluminum block so its not as strong?

 

 

LT1

Pros:

cheaper engine and parts/mods

more parts and swappable with other SBC 350's

a little thinner than an LS1

stronger iron block

R&D still being done on them

 

Cons:

opti spark is a PIA

heavier engine

older, R&D slowing down to mod

less power out of the box

 

 

would also like to find out which engine can handle the most power more reliably, i plan on building them the right way also, so if i end up turbocharging it, it will be on low boost until i get the internals built up (i plan on boosting it eventually which is the reason for the question) , so if both had built internals which would last longer under boost and be able to handle more power

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Other than money I can't think of a reason to go with an LT1 over an LS1. The heads are much, much better from the factory. I've heard of people hitting over 400 RWHP with a cam swap on stock heads. You'd be lucky to get that with heads/cam on an LT1. LS1's also have a better ignition system, 6 bolt mains, and you can swap a cam without pulling the intake manifold. As far as longevity, some people say the LS1 isn't going to last as long with an aluminum block. On the other hand there are no LT1's in the 8's, while at least one LS1 car has done that.

 

It's really just a question of money. You could find a 2-bolt main LT1 for ~1k used and running. Corvette 4-bolt blocks are a bit more, and LS1's are substantially more expensive. If you're going to build it up and go nuts with it you might be better off to go with an LT1 and put the money you save over an LS1 into mods. On the other hand, a heads/cam LS1 laying down well over 400 RWHP would be crazy fast in a car that light. If not, you can spray it. :D

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Guest stevil

I'd go with the LS1, depending on my budget. Either that or just go SBC. The LT1 is sort of the inbetween mix.

 

I think the LS1 engine is a bit taller, not wider. Notice the LS1 hoods are taller, and more rounded, thats why. The LT1 hoods have a sharper angle. Either that or they are just mounted higher.

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i know the LS1's r also wider for sure, dont know how tall either one is, but they both fit without any modifications to the hood so thats no problem

 

im trying to think if money was not put into the equation, if i built up the internals, what kind of reliability would be expected with about 550-600hp maybe even 700hp, my goal is to atleast have around 600hp so i would like to find out the reliability for them

 

i plan on turbocharging it so i can turn down the boost for just when im driving and not have so much power and save a little gas, but to have it there when i want/need it, and because of this im leaning more towards the LS1 to save some weight for the added weight of the turbo system, but thats also where the width comes in for the LS1 being wider, might cause a little more trouble but it will prolly cost just the same for the fabricated piping

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the LS1 is far and above a better engine. the LT1 is based on the original SBC, and considering what some of the specialized parts for it cost, i'd just get a 1st gen SBC if money is the biggest issue...

 

even though the block is aluminum, i'd say the block itself is stronger. you've got 6 bolt (crosbolted if i remember correctly) mains, deep skirted main caps, and better cylinder head sealing, which is critical for boosting. the cylinder heads themselves are superb, and the port design is not compromised by the valvetrain layout like the earlier engines. the only problem really with LS1 engines are cost...

 

another idea would be to use a ford modular... tongue.gif

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Originally posted by Saint:

im trying to think if money was not put into the equation

Well then that's easy. LS1. I don't know how you can directly compare the reliability of a built LS1 and LT1 though. There are so many different setups,combos, builders, etc. that an even comparison is impossible. If you build either correctly w/ forged internals they will be able to handle about all you can throw at either of em...

 

But the fact is I'm pretty sure money WILL be in the equation. It's not very realistic to think otherwise. You need to set a budget and then performance goal.

 

Once you set a budget or $$ limit it's alot easier to make a comparison. For instance, if you set yourself a limit of $10grand on the engine you can work within that framework. You can price LT1 and LS1s engines and then heads/cams and stroker kits for each. And then you can take a look a power adders and such..

 

If you have a bottomless wallet and want to know which you can go the absolute fastest.. The simple answer is LS1. Obviously, it's a better engine. They took the LT1 and improved. Does that mean that an LT1 isn't able to reach your performance goals? I'd have no idea, but HIGHLY doubt it..

 

Anyways, again.. budget and goals. Then you can determine if it is realistic money wise to opt for an LS1 and if your performance goals will surpass what you can do w/ an LT1..

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thats the thing, i dont know how much money im going to put in it, im planning on boosting it most likely, maybe not in the near future but i plan on always doing something to it, right now im thinking what i would do in the long term so i know which engine to start with so i dont end up getting to a stop and regretting which engine i chose
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As Sam said, it is all about the money.

 

If you have a bottomless wallet and swaping in a motor to something, you'd be a retard to buy EITHER. You'd go with a Gen-I SBC, nice aftermarket block, FAST, MoToTec or another nice aftermarket PCM, maybe some 15 or 18 degree heads, etc.

 

Otherwise, block work on an LS1's is fawking EXPENSIVE. Seems getting head work done on an LS1's isn't nearly as cheap as an LT1 either. Hell, most parts are cheaper for an LT1. I've also heard bolt pattern for the heads on the LS1 isn't as strong as the GEN-1 and II SBC's (probably do to their different intake/exhaust valve setup).

 

Now building an IRON block LS1 shortblock is significantaly cheaper, but there goes some of your weight savings.

 

And I swear, the whole Optispark thing is taken WAY out of hand. Sure, they are not the most reliable things, but its not like they go out every 3k miles. :rolleyes: Yes, you CAN get rid of it (for a price), but hell, some of the fastest LT1's are STILL running it (usually just for the low voltage optical side of it).

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well, another consideration is that its going to be a semi daily driver too, i've made up my mind that its an LT1 or an LS1 going into it, unless i somehow really come into some money and then ill just get an LS6

 

im pretty much leaning mainly towards an LS1 so how much power would a typical LS1 be able to handle if the compression ratio was lowered and forged internals on boost?

 

like an example i know smokinhawk's firebird is turbocharged and how much hp it has, so how long would that engine be expected to last if nothing else was added to it?

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Originally posted by 'No Boost For You':

the LS1 is far and above a better engine. the LT1 is based on the original SBC, and considering what some of the specialized parts for it cost, i'd just get a 1st gen SBC if money is the biggest issue...

 

even though the block is aluminum, i'd say the block itself is stronger. you've got 6 bolt (crosbolted if i remember correctly) mains, deep skirted main caps, and better cylinder head sealing, which is critical for boosting. the cylinder heads themselves are superb, and the port design is not compromised by the valvetrain layout like the earlier engines. the only problem really with LS1 engines are cost...

 

another idea would be to use a ford modular... tongue.gif

I don't think I'll agree with you on that one. The LS1 is by far easier to work on, but a better motor, I won't agree with... both motors have their problems as do any motor.....

 

have you maybe thought about an LT4? those heads flow ALLOT better than LT1 heads.... you can get some nice power out of them.

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Originally posted by Josh Miller:

have you maybe thought about an LT4? those heads flow ALLOT better than LT1 heads.... you can get some nice power out of them.

Well if he is gonna go full blown I don't think he'd waste his time w/ LT4 heads.. And I don't think they flow a LOT better.. maybe a non-capitalized "lot" at best. ;) But ported LT1 vs ported LT4 heads aren't much different..

 

 

Matt, you are still being very vague about what you're shooting for tongue.gif . A 500,600 or even 700 rwhp boosted LT1 can be done quite reliably w/ a properly built bottom end and proper tuning..

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Originally posted by SamZman:

Well if he is gonna go full blown I don't think he'd waste his time w/ LT4 heads.. And I don't think they flow a LOT better.. maybe a non-capitalized "lot" at best. ;) But ported LT1 vs ported LT4 heads aren't much different..

 

 

Matt, you are still being very vague about what you're shooting for tongue.gif . A 500,600 or even 700 rwhp boosted LT1 can be done quite reliably w/ a properly built bottom end and proper tuning..

I capitolized allot for a reason... my heads are ported just about as much as they can be for LT1 heads...... I use LT4 intake gaskets on it, so I'll say allot better since my heads really can't be ported anymore and I'm using stock LT4 gaskets tongue.gif
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Originally posted by SamZman:

Matt, you are still being very vague about what you're shooting for tongue.gif . A 500,600 or even 700 rwhp boosted LT1 can be done quite reliably w/ a properly built bottom end and proper tuning..

well i guess the reason im being a bit vague is because i dont know exactly what i would need, just what i want to shoot for which is ~600rwhp

 

so far i just know the quickest way is to get an LS1 with an LS1MS single turbo kit and working the engine and setting it up for more boost

 

thats pretty much what i've decided to work for already, but i just wanted to make sure that it will be able to handle it reliably and last a good deal of time on that setup, i dont plan on running it at that power ALL the time, i just want it there when i want to use it, otherwise the boost will be turned down to just maybe ~450hp for daily driving until someone wants a piece :cool:

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Guest Hot Rod
Originally posted by SamZman:

Well if he is gonna go full blown I don't think he'd waste his time w/ LT4 heads.. And I don't think they flow a LOT better.. maybe a non-capitalized "lot" at best. ;) But ported LT1 vs ported LT4 heads aren't much different..

I think LT4 heads have just a slight advantage over LT1s non ported and fully ported. . .

 

A = LT1 B = LT4

 

Intake

http://home.tir.com/~steveher/intake.jpg

 

Exhaust

http://home.tir.com/~steveher/exhuast.jpg

 

My performance LT4 intake gaskets swallow stock LT1 and stock LT4 gaskets. . .

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Originally posted by Josh Miller:

I don't think I'll agree with you on that one. The LS1 is by far easier to work on, but a better motor, I won't agree with... both motors have their problems as do any motor.....

the LT1 was an bandaid attempt at fixing some of the shortcomings of the original 1st gen SBC. they made revisions to the cooling system, ignition, and several other things, but the general architecture of the original SBC engine remained...

 

then the engineers at GM realized the LT1 or another revision of that engine design would never meet their performance and emissions goals, so they wiped the slate clean and started from scratch with the LS1, designing a more efficient engine with the 40 or so years of experience they had with the original small block...

 

the end result is an engine with a stronger block, uncompromised cylinder head ports, much better sealing, and an improved ignition and cooling system. it also makes more power... tongue.gif

 

i'm not saying the engine doesn't have its quirks, but it's still a better engine that the LT1...

 

 

with regards to nitrousbird's comment on a weaker bolt pattern, i haven't heard that but i do have a few things to add on that topic. if i remember correctly, the head bolts on the LS1 thread deep into the engine's main webs, clamping the head down better than earlier engines, and they don't go into the water jackets like the earlier engines, eliminating any chance of a leak.

 

also, the LS1 uses a square shaped four bolt pattern around the cylinder. earlier engines used a star shaped five bolt pattern. maybe it's just a rumor, but from what i've read, the new pattern is to allow 4 valve cylinder heads on the engine... ;)

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Originally posted by 'No Boost For You':

the LT1 was an bandaid attempt at fixing some of the shortcomings of the original 1st gen SBC. they made revisions to the cooling system, ignition, and several other things, but the general architecture of the original SBC engine remained...

 

then the engineers at GM realized the LT1 or another revision of that engine design would never meet their performance and emissions goals, so they wiped the slate clean and started from scratch with the LS1, designing a more efficient engine with the 40 or so years of experience they had with the original small block...

 

the end result is an engine with a stronger block, uncompromised cylinder head ports, much better sealing, and an improved ignition and cooling system. it also makes more power... tongue.gif

 

i'm not saying the engine doesn't have its quirks, but it's still a better engine that the LT1...

 

 

with regards to nitrousbird's comment on a weaker bolt pattern, i haven't heard that but i do have a few things to add on that topic. if i remember correctly, the head bolts on the LS1 thread deep into the engine's main webs, clamping the head down better than earlier engines, and they don't go into the water jackets like the earlier engines, eliminating any chance of a leak.

 

also, the LS1 uses a square shaped four bolt pattern around the cylinder. earlier engines used a star shaped five bolt pattern. maybe it's just a rumor, but from what i've read, the new pattern is to allow 4 valve cylinder heads on the engine... ;)

There are downfalls on the LT1 as well as the LS1.... I didn't deny that..... the backwards cooling system, opti spark..... etc.... the LS1 has their's too oil pump, shitty composite intake, weak piston rings, shitty rod bolts, me not owning one.. etc... ;)

 

what I am trying to say is that LT1's are good motor, if you find one that was treated right, it still will produce more power than what you will want. I would probably go with an LT1 just because of the fact that they are cheaper which means more mod money and I'm sure you're on a budget.

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Originally posted by Josh Miller:

There are downfalls on the LT1 as well as the LS1.... I didn't deny that..... the backwards cooling system, opti spark..... etc.... the LS1 has their's too oil pump, shitty composite intake, weak piston rings, shitty rod bolts, me not owning one.. etc... ;)

 

what I am trying to say is that LT1's are good motor, if you find one that was treated right, it still will produce more power than what you will want. I would probably go with an LT1 just because of the fact that they are cheaper which means more mod money and I'm sure you're on a budget.

the backwards cooling system on the LT1 was pretty cool if you ask me... ;)

 

as far as the problems with the stock internals on the LS1, i usually don't consider that in a high output application, since they tend to get replaced with stronger aftermarket pieces anyways...

 

as far as using the LT1 because it's cheaper, i couldn't agree with you more. saving money is almost always important. hopefully as the LS1 finds it way into more and more cars and trucks, the price will come down...

 

i don't think the LT1 is a bad engine by any means. i almost bought an LT1 car a while back. just given the choice between the LS1 and LT1, i'd recommend the LS1 as long as money wasn't THAT much of an issue... ;)

 

i still like the ford modular better though... tongue.gif

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Originally posted by 'No Boost For You':

the backwards cooling system on the LT1 was pretty cool if you ask me... ;)

 

as far as the problems with the stock internals on the LS1, i usually don't consider that in a high output application, since they tend to get replaced with stronger aftermarket pieces anyways...

 

as far as using the LT1 because it's cheaper, i couldn't agree with you more. saving money is almost always important. hopefully as the LS1 finds it way into more and more cars and trucks, the price will come down...

 

i don't think the LT1 is a bad engine by any means. i almost bought an LT1 car a while back. just given the choice between the LS1 and LT1, i'd recommend the LS1 as long as money wasn't THAT much of an issue... ;)

 

i still like the ford modular better though... tongue.gif

haha... dude, you're just asking for a flame war! tongue.gif He said he want's power... why on earth would he go with a ford? ... haha.... you asked for it ;)
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