LS3/LS6/LS2/LS9/LS7...what are the differences

[Bobby "Big Daddy" Flay]

What are the differences between these motors as well within the same platforms they may be in?

[BAD LS1]

Too many Little things to list. Goggle it, should be alot of write ups explaining all of this .

[GTSLOW]

Blocks, intakes, heads, cams, etc.... the thing about them is a lot of it is interchangeable between. That is what makes them so popular. Somethings like intake manis are not interchangeable but the head they mount to is.

[Taetsch Z-24]

They are different?

HmM.

[Cryptic]

Buy this book.
http://www.books4bestseller.com/images/nonfiction-automotive/how-to-build-and-modify-gm-ls-series-engines-motorbooks-workshop.jpg
http://www.amazon.com/Build-Modify-Engines-Motorbooks-Workshop/dp/0760335435

Its a good read and written by one of the mods at LS1Tech

[GTSLOW]

Something worth noting. The factory LS2 intake despite having a 90MM TB was the biggest pos of the bunch.

[TransAm12sec]

http://en.wikipedia.org/wiki/GM_LS_engine

What happened that the LS2 flowed worse than the previous LS6?

People at GM said: Here's a good design, let's make it worse.

[BAD LS1]

http://en.wikipedia.org/wiki/GM_LS_engine

What happened that the LS2 flowed worse than the previous LS6?

People at GM said: Here's a good design, let's make it worse.

This is just my hypothetical look at the LS2 vs LS6 intake. The LS6 was a one piece injection molding with smallish inlet neck but smooth radius turns into the runners and no petruding edges into the ports. The LS2 is a multi-piece, plastic welded intake with sharp edges and sloppy intersections which inhibit flow. These things have rather tall edges that stick out into the intake ports too. Alot of time went into accoustic tuning of the plenum portion of the LS6 intake to help use sound waves to ram tune the moving air. I highly doubt this part was overlooked or misunderstood by GM, BUT the way i look at it - bigger is not always better when talking intake manifolds. The LS2 has a 90mm inlet neck which untimately slows the velocity of the incoming air if the engine can't consume it all fast enough to keep the speed up. When that velocity goes away, the natural supercharging effect of moving air sped up by a sort of venturi effect drops out with it thus resulting in a intake that is a performance bottle neck. This is a common misconception that i see people make when putting a FAST intake on that errors to the enormous size side like a 102mm on a 346" LS1, airflow stalls in this thing at low engine speed because you dont have enough engine under it to use the increase in flow potential. The same can be said for cylinder heads with way too much port volume for a given size of the engine or porting in all the wrong areas. Will these HUGE intake make more power on even a 346? Yes. but where? at peak! and torque production goes in the toilet under the curve due to the less than efficient cylinder filling at lower RPM. Sorry for the long drawn out rant, its a pet pieve of mine when people spend the money on stuff that will yield very little in the end because they are misinformed and the money could have been better spent elsewhere gotten more overall gains.

[TransAm12sec]

That wasn't a rant; that was good observation.

[BAD LS1]

The LS6 intake that has the neck modified to mount the 90mmTB on a LS2 is apparently worth 20 +throughout the whole curve. I look at intake manifolds as "just in time" service. I visualize the plenum acting like a sponge for the engine to draw from while the incoming airflow through the air intake system delivers a batch of air to replace the air in the plenum just in time. This keeps things moving w/o shortage or over abundance at any given time. Basically if you have too large of plenum or reservoir and not enough engine to deplete that resivior, alot of time passes before engine uses it all up and creates a a strong enough low pressure signal to draw a fresh batch in to fill the sponge again.

[Taetsch Z-24]

So, if you don't mind me asking, how is the stock LS7 intake with a 90MM TB on it?
On the inside I can see the runners coming in to the plenum also...

[BAD LS1]

^^^much more refined piece! Also, more engine under the intake to make use of the size. The LS2 intake i feel was the subject of a cost reduction as the LS6 was probably a bit pricey to produce.

[SSLEVO]

Ls6 is a gen III where all the other engines are gen IV's i believe.

LS6 was first, 405hp (C5 Z06 vette)
LS2 came along with a bump in displacement to 6.0L using the ls6 heads and crappier intake, 400 hp (06-07 CTS-V, 05-06 GTO 05-07 vette) .
LS7 came next as a 505hp 7L with new cnc ported heads and a lot of trick components (06-present C6 Z06)
LS3 came out in 08 as a 430 hp 6.2L and has heads similar to the un-ported ls7 heads (08-present vette, 10-present camaro ss)

[GTSLOW]

The LS2 had LS6 heads? I'm pretty sure the LS6 intake would not work on my car minus the TB issues. Speaking more towards the head ports, etc..

[SSLEVO]

yeah, they had the same 243 heads, spacing may be different though

http://en.wikipedia.org/wiki/GM_LS_engine

[Taetsch Z-24]

LS7 came next as a 505hp 7L with new cnc ported heads and a lot of trick components (06-present C6 Z06)
LS3 came out in 08 as a 430 hp 6.2L and has heads similar to the un-ported ls7 heads (08-present vette, 10-present camaro ss)

Not true.

Taken out of 2011 GMPP book, page 196




Stock LS7 Head( UNPORTED AND PORTED): 270 port size (intake), 12* valve angle, 70cc Chamber, 2.20 intake valve, 1.61 Ext, ports on non CNCed LSX7 heads are “as cast” Intake valves are Titanium.

Stock LS3 Head 260 port size (intake), 15* valve angle, 68.4cc Chamber, 2.16 intake valve, 1.59 Ext, Intake valve are hollow Inlet port type L92.


Little differences, but looking at them, the ls3 port LOOKs larger.

Looks can be deceiving.

[SSLEVO]

Not true.

Little differences, but looking at them, the ls3 port LOOKs larger.

Looks can be deceiving.

Notice where i said SIMILAR, not exact.

[Taetsch Z-24]

That can be said about all LSx heads then...