Discussion
Hello,
Currently looking at engine choices for my Ultima. I want around 600bhp and it must be able to do track days reliably with no oil surge problems etc.
After reading threads about the new engine of choice, the LS7 I thought that my choice had been made for me and that was the engine for me.
Spoken to a very nice chap breifly on the phone today and he mentioned that the LS3 might be a better proposition for my needs because it can be easily tuned and offer more scope for more power in the future?
Has anyone had the same dilema? What do you chaps think?
David.
Currently looking at engine choices for my Ultima. I want around 600bhp and it must be able to do track days reliably with no oil surge problems etc.
After reading threads about the new engine of choice, the LS7 I thought that my choice had been made for me and that was the engine for me.
Spoken to a very nice chap breifly on the phone today and he mentioned that the LS3 might be a better proposition for my needs because it can be easily tuned and offer more scope for more power in the future?
Has anyone had the same dilema? What do you chaps think?
David.
You can get 1000hp from an LS7, how much more scope do you want? 
It's reasonable to assume that you would get 550hp from the LS7 with the standard GM ECU with no need for dyno tuning, rolling roads etc. These are costs that you would incur with a non standard engine. Plus the LS7 in standard tune will always start and run like a new production car engine.
It's reasonable to assume that you would get 550hp from the LS7 with the standard GM ECU with no need for dyno tuning, rolling roads etc. These are costs that you would incur with a non standard engine. Plus the LS7 in standard tune will always start and run like a new production car engine.
An ls3 is the poor mans pretender when compared to an ls7. Sure it's a great engine but it's a factory budget build, no titanium anywhere and not built to the same strict tolerences as an ls7. The ls7 also has better main caps and a better block then an ls3. in fact just about everything's better then an ls3.
It's really down to money. The 7 is superior in a lot of ways whereas the 3 is better value for money and not that far behind in the performance stakes.
I'd just have to have an ls7, well I do
It's really down to money. The 7 is superior in a lot of ways whereas the 3 is better value for money and not that far behind in the performance stakes.
I'd just have to have an ls7, well I do
s62 said:
It´s 2009 - why on earth would you put a carbed engine in an Ultima 
I can see the attraction even if it does seem a backward step. Anything that's been modded may need a remap on a dyno and add that to the cost of the efi kit, injectors and loom etc it gets very expensive. A carb can be diy with no expert help.I really can't see the attraction of the LS 3. To get to the LS 7 output you need a cam, dyno setup and an expensive dry sump conversion. Why bother when the LS 7 has the nice internal bits as well, straight out of the box.
Presumably the comments about running an LS with a carb is a joke...
Presumably the comments about running an LS with a carb is a joke...
Rusti Evo said:
I really can't see the attraction of the LS 3. To get to the LS 7 output you need a cam, dyno setup and an expensive dry sump conversion. Why bother when the LS 7 has the nice internal bits as well, straight out of the box.
Presumably the comments about running an LS with a carb is a joke...
simply the LS7 is not as strong as the 2/3 ..... the rods are light but there has been a lot of problems with them shattering.Presumably the comments about running an LS with a carb is a joke...
the standard LS7 dry sump system is poor and to make it a 'proper' dry sump system it needs upgrading!!
pros and cons for both engines imo but you will have to map them both to get the best out of them.
yep i agree why on earth would you want to put a carb on a LS?? unless its regulation driven ie motorsport.
This debate has been around for a while now, but there hasn't been any quantifiable data shown detailing the merits of either.
LS7s aren't as strong - how many have let go, what is that %age of those out there. How does that compare to a tuned LS2/3 letting go?
What's the cost get an LS2/3 to LS7 spec? Is the LS2/3 then "better"?
For £12ish k you get a 5-550hp, standard LS7 engine with all the gubbins, £14k for approx 600hp.
What is the cost for this on an LS2/3, with a dry sump etc and what is the expected lifespan?
I want reliability first, power second. Ls7 seems perfect for me unless someone can prove a tuned LS2/3 will offer more?
LS7s aren't as strong - how many have let go, what is that %age of those out there. How does that compare to a tuned LS2/3 letting go?
What's the cost get an LS2/3 to LS7 spec? Is the LS2/3 then "better"?
For £12ish k you get a 5-550hp, standard LS7 engine with all the gubbins, £14k for approx 600hp.
What is the cost for this on an LS2/3, with a dry sump etc and what is the expected lifespan?
I want reliability first, power second. Ls7 seems perfect for me unless someone can prove a tuned LS2/3 will offer more?
The only UK ls7's that I've heard of letting go have IMO had mapping issues and detonation. These were/are track racers running aftermarket ecu's so it's easy to get it wrong. The stock ecu seems perfectly capable on a stockish engine and due to knock sensors will offer a degree of protection using GM maps.
I've never heard of any inherant faults with the Ti rods which just have to be better then an ls3 rod at 7000 rpm's.
If building for more power then both engines would have a cam change and possibly a piston change to forged items so I can't see where it would cost more to upgrade an ls7. It has juicy bits already so a lot of parts wouldn't need upgrading.
Don't know much about the sumps but I'm going to use mine as I don't have a GT racer.
I've never heard of any inherant faults with the Ti rods which just have to be better then an ls3 rod at 7000 rpm's.
If building for more power then both engines would have a cam change and possibly a piston change to forged items so I can't see where it would cost more to upgrade an ls7. It has juicy bits already so a lot of parts wouldn't need upgrading.
Don't know much about the sumps but I'm going to use mine as I don't have a GT racer.
LS7 is okay and the stock TI alloy bits will do their 'designed job'...... but if you are planning a serious motor in the future you want to upgrade either engine with good quality forged internals. So, if you think that might be you in the no-too-distant, there seems no point buying expensive TI bits to throw away for a mere 35-40HP initial gain. (LS3 480 vs LS7)
Better spending your pennies on a well matched box and accusump initially!
Better spending your pennies on a well matched box and accusump initially!
To me Peter Knights experience in the Britcar 24 hour shows the extraordinary robustness of the LS 7.
Straight out of the box (just converted to Motec) no test running, races for 24 hours - perfect. He says that engine is doing its second 24 hr Britcar this year.......... gasp
Compared to that sort of extreme environment our little track days are just a stoll in the park for the LS 7
Straight out of the box (just converted to Motec) no test running, races for 24 hours - perfect. He says that engine is doing its second 24 hr Britcar this year.......... gasp
Compared to that sort of extreme environment our little track days are just a stoll in the park for the LS 7
Boosted LS1 said:
The only UK ls7's that I've heard of letting go have IMO had mapping issues and detonation. These were/are track racers running aftermarket ecu's so it's easy to get it wrong. The stock ecu seems perfectly capable on a stockish engine and due to knock sensors will offer a degree of protection using GM maps.
I've never heard of any inherant faults with the Ti rods which just have to be better then an ls3 rod at 7000 rpm's.
If building for more power then both engines would have a cam change and possibly a piston change to forged items so I can't see where it would cost more to upgrade an ls7. It has juicy bits already so a lot of parts wouldn't need upgrading.
Don't know much about the sumps but I'm going to use mine as I don't have a GT racer.
plenty of evidence of rods through blocks with the 7 and pictures on ls1tech.comI've never heard of any inherant faults with the Ti rods which just have to be better then an ls3 rod at 7000 rpm's.
If building for more power then both engines would have a cam change and possibly a piston change to forged items so I can't see where it would cost more to upgrade an ls7. It has juicy bits already so a lot of parts wouldn't need upgrading.
Don't know much about the sumps but I'm going to use mine as I don't have a GT racer.
Thanks Gulf,
I'll take a look. I'd be surprised if the issues could be blamed specifically on the rods though. More like a faulty tune with some detonation thrown in or a different engine application/installation where something's different.
I wonder if there have been many failures in vette installations where the pcm offers some protection and revs remain near stock?
I'll take a look. I'd be surprised if the issues could be blamed specifically on the rods though. More like a faulty tune with some detonation thrown in or a different engine application/installation where something's different.
I wonder if there have been many failures in vette installations where the pcm offers some protection and revs remain near stock?
Boosted LS1 said:
Thanks Gulf,
I'll take a look. I'd be surprised if the issues could be blamed specifically on the rods though. More like a faulty tune with some detonation thrown in or a different engine application/installation where something's different.
I wonder if there have been many failures in vette installations where the pcm offers some protection and revs remain near stock?
probably not!!I'll take a look. I'd be surprised if the issues could be blamed specifically on the rods though. More like a faulty tune with some detonation thrown in or a different engine application/installation where something's different.
I wonder if there have been many failures in vette installations where the pcm offers some protection and revs remain near stock?
Ti is a brittle material under compression imo ive seen a lot of golf club heads explode. Its lovely and light but running it with a blower would worry me but i suppose powder LS3 rods may struggle as well??
I know ProCharger made 700bhp with 6psi on a standard internalled LS7 and its now done 30k!!!
Edited by Gulf -LS2 on Thursday 23 July 18:27
Gassing Station | Ultima | Top of Page | What's New | My Stuff