Cadillac CTS-V Forum banner
1 - 19 of 19 Posts

·
Registered
Joined
·
36 Posts
Discussion Starter · #1 ·
I have read a few threads about distortion issues with the LSA block but I would like to know if anyone has gotten one to survive at 1300+whp. I am planning a drag week build for 8.50 class which requires a minimum weight of 3200lbs and some other very limiting factors for my C6 corvette chassis. Obviously this will get driven regularly on the street (4000+miles per year) and must survive 30-40 passes per year for the next 3 years. What are your thoughts on the below combination and what can I do to improve reliability:

LSA block with 4.070 bore, 9.230 deck height, ACL H bearings and factor oil squirters
LSA crank- stock
Molnar power adder PLUS rods
Diamond pistons from Dedicated motorsports w/ .205 wall wrist pins yielding 11.26:1 compression
LS9 CNC heads from GM with 66.5CC chamber, titanium intake valves and sodium filled exhaust valves
BTR Stage 3 turbo cam
S491 with 102mm turbine wheel 1.30 v-band housing
hi-ram with 210 injectors and LS3 90mm throttle body
e-85
LSA oil pump
ARP main studs
ARP 2000 Head studs for LSA
ATI Damper

Rotating assembly will be balanced by a local machine shop

I am hoping rubber duck and some of the other long time contributors to this forum can enlighten me on issues I may run into and possible solutions. Would even like to talk to someone over the phone if interested
two four eight four one zero four four three eight

Thanks
Matt
 

·
Administrator
Joined
·
21,854 Posts
I would say you will be in bad shape. Not only the crank wanting to move, and the mains will move, but you will also have a hard time holding the gasket.

Why use those heads at 1300hp?


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
36 Posts
Discussion Starter · #3 ·
I was thinking the heads were a good cheap alternative to aftermarkets and have lightened valvetrain for the 7500+rpm that i plan to run. $2118 for the set
I forgot to mention in my original post i will be using Johnson ST2126LSR lifters.

I'm afraid you may be right with the block not wanting to hold the power. What alternative do we have for an aluminum block that will hold the power and not cost $5k+

My previous engine was a completely stock LC9 with opened ring gaps and LJMS stage 2 cam that is still running at 900whp for over 3 years and made 146 passes in the high 9 sec range in a very heavy car.
 

·
Administrator
Joined
·
21,854 Posts
You do know that good and cheap are very close to being mutually exclusive.

They might be a good value, but since you are chasing 1300hp, you need power (fuel, turbos, cam, and heads) and seek longevity (block, crank, rods, rings, bolts, machining. Add all the rest, like pistons, ring seal, etc, and, well, speed costs money, get ready to spend it.

That’s my 2 cents. Best of luck.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
1,487 Posts
The turbo is going to be much easier on parts. IMO, an LSA crank will get you there. There are plenty of imported cranks making that power too. I think the problem with the block will be the cylinder walls. It seems a gamble at what hp they crack.

The cheap option in an aluminum gen 4 5.3 block. If you can live with the small bore, the stock sleeves are thick. If you want more bore, you have to sleeve it. With a small bore, you mostly be stuck with cathedral port heads.
 
  • Like
Reactions: Rubber Duck

·
Premium Member
Joined
·
5,007 Posts
I have read a few threads about distortion issues with the LSA block but I would like to know if anyone has gotten one to survive at 1300+whp. I am planning a drag week build for 8.50 class which requires a minimum weight of 3200lbs and some other very limiting factors for my C6 corvette chassis. Obviously this will get driven regularly on the street (4000+miles per year) and must survive 30-40 passes per year for the next 3 years. What are your thoughts on the below combination and what can I do to improve reliability:

LSA block with 4.070 bore, 9.230 deck height, ACL H bearings and factor oil squirters
LSA crank- stock
Molnar power adder PLUS rods
Diamond pistons from Dedicated motorsports w/ .205 wall wrist pins yielding 11.26:1 compression
LS9 CNC heads from GM with 66.5CC chamber, titanium intake valves and sodium filled exhaust valves
BTR Stage 3 turbo cam
S491 with 102mm turbine wheel 1.30 v-band housing
hi-ram with 210 injectors and LS3 90mm throttle body
e-85
LSA oil pump
ARP main studs
ARP 2000 Head studs for LSA
ATI Damper

Rotating assembly will be balanced by a local machine shop

I am hoping rubber duck and some of the other long time contributors to this forum can enlighten me on issues I may run into and possible solutions. Would even like to talk to someone over the phone if interested
two four eight four one zero four four three eight

Thanks
Matt
The LSA Crank is the same Crankshaft that is used in the GM lsX Iron Block. GM warrants this crank to 900 fwHP. However, some have used that crank to make well over 900 fwHP. In spite of that, I highly suggest you purchase a higher quality crankshaft also having center counterweights.

Those crankshafts do help to help to stiffen up the crankshaft at the higher power level, which is exactly what the LSA Crank requires.

As pointed out by others already; Your two biggest problems from what I can see today, are the block and the heads.

Frankly, and don't take this wrong; your 'Kidding Yourself' if you think that a 4-Bolt head is going to seal that much power / cylinder pressure. Also, your kidding yourself thinking that the stock LSA block is going to retain a round cylinder with that much power.

So if your not blowing head gaskets, the oil in the cylinders will reduce the octane to such a degree that you will find the engine going into self-detonation as heat builds up within the engine.

Again, don't take this wrong; but there are no short cuts with aN 1300 HP Engine Build you can safely take, using essentially an LS-9 Engine.

Cheers,
RD
 

·
Premium Member
Joined
·
5,007 Posts
I am planning a drag week build for 8.50 class which requires a minimum weight of 3200lbs and some other very limiting factors for my C6 corvette chassis. Obviously this will get driven regularly on the street (4000+miles per year) and must survive 30-40 passes per year for the next 3 years. What are your thoughts on the below combination and what can I do to improve reliability:
With a 'Sense of Humor'. . . . Short answer to that one is. . . . .

Font Magenta Signage Brand Graphics
 

·
Registered
Joined
·
36 Posts
Discussion Starter · #9 ·
Thanks guys for jumping into this discussion.
I'm an engineer so I like to talk with facts.

Here is what i am hearing so far:
1. Bore distortion is a concern with the block
-At what cylinder pressures are we seeing this?
-Are there any ways to alleviate this other than sleeving or filling?
2. Head gasket sealing with 4 bolt heads
-We could use 1/2" or 12mm studs since I'm already using the LS( heads which will accept them)
-gasket ideas, i have always used LS9 gaskets but maybe an athena or hoops?
3. Rubber Duck mentioned heads but didn't say why they are an issue
-My reason for choosing LS9 CNC GM heads is price ($2118), Flow (~350CFM at .600"), smaller chamber (66.5cc) and light valvetrain for high RPM use
4. Crank rigidity
- I have considered using the new GM L8T crank which would add the CCW that rubber duck mentioned. (this would also increase stroke to 3.855 which puts more stress on the cylinder walls)


It doesn't seem we have many data points but as Mean Mike mentioned, the turbo setup should be much easier on parts. I would love to talk to someone else running a large single turbo on a somewhat stock LSA/LS9. I see a writeup done on Steve Morris 1200chp LS3 with very similar components that supposedly made 100 dyno pulls at that power during a cam test.
 

·
Registered
2012 CTSV coupe
Joined
·
420 Posts
Honestly you have heard everything you need on this. The LSA block is not the platform for those HP levels. There is significant blow by even at the 850whp level on the LSA. Ask me how i know.

Add in the crank and non priority oiling and you will struggle to have any reliability at those levels.

Sent from my SM-N975W using Tapatalk
 

·
Registered
2011 Black Wagon
Joined
·
227 Posts
Band-aid on a sucking chest wound…

Opposed to running the LSX iron block as RD mentioned? If you’re trying to stay in that weight class, shed some pounds.


Sent from my iPhone using Tapatalk
 

·
Premium Member
2011 CTS-V Coupe M
Joined
·
44 Posts
I have read a few threads about distortion issues with the LSA block but I would like to know if anyone has gotten one to survive at 1300+whp. I am planning a drag week build for 8.50 class which requires a minimum weight of 3200lbs and some other very limiting factors for my C6 corvette chassis. Obviously this will get driven regularly on the street (4000+miles per year) and must survive 30-40 passes per year for the next 3 years. What are your thoughts on the below combination and what can I do to improve reliability:

LSA block with 4.070 bore, 9.230 deck height, ACL H bearings and factor oil squirters
LSA crank- stock
Molnar power adder PLUS rods
Diamond pistons from Dedicated motorsports w/ .205 wall wrist pins yielding 11.26:1 compression
LS9 CNC heads from GM with 66.5CC chamber, titanium intake valves and sodium filled exhaust valves
BTR Stage 3 turbo cam
S491 with 102mm turbine wheel 1.30 v-band housing
hi-ram with 210 injectors and LS3 90mm throttle body
e-85
LSA oil pump
ARP main studs
ARP 2000 Head studs for LSA
ATI Damper

Rotating assembly will be balanced by a local machine shop

I am hoping rubber duck and some of the other long time contributors to this forum can enlighten me on issues I may run into and possible solutions. Would even like to talk to someone over the phone if interested
two four eight four one zero four four three eight

Thanks
Matt
If you have not already made any purchases, I suggest an LSX376-B15 long block with an E67 ECM and CTSV FPCM.
 

·
Registered
Joined
·
36 Posts
Discussion Starter · #14 ·
Honestly you have heard everything you need on this. The LSA block is not the platform for those HP levels. There is significant blow by even at the 850whp level on the LSA. Ask me how i know.

Add in the crank and non priority oiling and you will struggle to have any reliability at those levels.

Sent from my SM-N975W using Tapatalk
Thanks Arctic white, Actually i would like to ask how you know. What is your experience with blow by and what is your setup?

Kittyboy- As you stated i am trying to keep the nose light so the extra 140lbs from an LSX is not desired for this build.

Do we think that this is the reason for cylinder distortion? I'm thinking the pressed in cylinders could have increased strength due to the interference fit of the outside of the pressed in liner. The cast in liners on our blocks have basically no compressive stress on them. I also wonder if the cast in liners are subject to worse positioning or core shift as some call it.

Rubber duck quote
"LS3 Block is a deep skirt cast A356-T6 ALUMINUM ALLOY with pressed in cylinders.

LSA and LS9 Block is a deep skirt cast 319-T7 ALUMINUM ALLOY, with cast-in-iron cylinders
and uses 4-Bolts per cylinder to affix the cylinder heads to the block, just as does an LS3."
 

·
Registered
2012 CTSV coupe
Joined
·
420 Posts
I put forged rods and pistons in my low mile LSA. At 16.5lbs of boost on ported aftermarket heads and with a moroso catch can i had enough blow by/crank case pressure that i blew out the front main seal.

I've got 10AN hose venting the crank now.

What you are talking about is well above this HP level. Even if you were to go to thicker sleeves and could solve this issue, the block has other issues at the power levels you are talking about.

You could put a bunch of money into it CCW crank etc but why put a whole bunch of money into a foundation (block) that simply isnt made for it. It might live depending on how you drive and stress it, but it is the opinion of many knowledgeable people that an LSA at those power levels isnt a "100 dyno pass" setup.

That said, learning by doing/first hand experience is a good teacher.

Sent from my SM-N975W using Tapatalk
 
  • Like
Reactions: Rubber Duck

·
Premium Member
Joined
·
5,007 Posts
I put forged rods and pistons in my low mile LSA. At 16.5lbs of boost on ported aftermarket heads and with a moroso catch can i had enough blow by/crank case pressure that i blew out the front main seal.

I've got 10AN hose venting the crank now.

That said, learning by doing/first hand experience is a good teacher.

Sent from my SM-N975W using Tapatalk
Congratulations, you have taken 'Blow By' to a new level.. :giggle:
 

·
Premium Member
Joined
·
5,007 Posts
Thanks guys for jumping into this discussion.
I'm an engineer so I like to talk with facts.

Here is what i am hearing so far:
1. Bore distortion is a concern with the block
-At what cylinder pressures are we seeing this?
-Are there any ways to alleviate this other than sleeving or filling?
2. Head gasket sealing with 4 bolt heads
-We could use 1/2" or 12mm studs since I'm already using the LS( heads which will accept them)
-gasket ideas, i have always used LS9 gaskets but maybe an athena or hoops?
3. Rubber Duck mentioned heads but didn't say why they are an issue
-My reason for choosing LS9 CNC GM heads is price ($2118), Flow (~350CFM at .600"), smaller chamber (66.5cc) and light valvetrain for high RPM use
4. Crank rigidity
- I have considered using the new GM L8T crank which would add the CCW that rubber duck mentioned. (this would also increase stroke to 3.855 which puts more stress on the cylinder walls)


It doesn't seem we have many data points but as Mean Mike mentioned, the turbo setup should be much easier on parts. I would love to talk to someone else running a large single turbo on a somewhat stock LSA/LS9. I see a writeup done on Steve Morris 1200chp LS3 with very similar components that supposedly made 100 dyno pulls at that power during a cam test.
Responding to your point number 3.
I was not referencing any issue regarding cylinder head flow.

I was referencing the issue of holding / clamping down a
cylinder head with only 4-Fasteners, not six (6), relative
to the cylinder pressures one would encounter at 1300 HP
rather than the 556 HP the engine makes stock.

Years back Porsche claimed they had overbuilt their cars
to that one could safely add 50% more power.

I don't remember GM making that statement with the LSA.
But I do know that GM rates their Iron Block lsX to 900 fwHP.

And I also know that GM representatives claim that a good
lsX block can be safely used up to 1500 fwHP.

--------------------------------------------------------------------

Did Steve Morris use a stock LS3 Block?

Cheers
 

·
Premium Member
Joined
·
5,007 Posts
Do we think that this is the reason for cylinder distortion? I'm thinking the pressed in cylinders could have increased strength due to the interference fit of the outside of the pressed in liner. The cast in liners on our blocks have basically no compressive stress on them. I also wonder if the cast in liners are subject to worse positioning or core shift as some call it.

Rubber duck quote
"LS3 Block is a deep skirt cast A356-T6 ALUMINUM ALLOY with pressed in cylinders.

LSA and LS9 Block is a deep skirt cast 319-T7 ALUMINUM ALLOY, with cast-in-iron cylinders
and uses 4-Bolts per cylinder to affix the cylinder heads to the block, just as does an LS3."
When the 'Big Bang' goes off just before TDC on the compression stroke,
'What material is supporting that thin sleeve". . . . .

It's Not Quality Iron such as with the GM lsX Iron Block!
It's not high quality 'Billet Aluminum' such as with CNC Blocks.
 
1 - 19 of 19 Posts
Top