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2011 A6 black diamond sedan.
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Discussion Starter · #1 · (Edited)
My current LSA had an extremely catastrophic failure.
There is really nothing salvageable and I think the stock blower my need new rotor also.

info in my intro thread

I've been researching for a few weeks.
I want something that will run on 91 octane, make decent power 6-700 at the wheels. Maybe more with meth inj?

I originally ordered a lsx 376 b-15, (no ETA) but now I'm second guessing that. Due to cam, oil pump, head bolts that are advised to change.
Also If I'm building something new I'm thinking I may as well add some displacement to bring up the torque and rely less on spinning it fast.
I'm also unsure of the 9:1 compression and think I may be better off with more compression, more cc and less boost. Maybe 10ish to 1 comp and keep the boost around 10psi?

I did get a build quote from Thompson.
LS3 416 block
all forged internals
Carrillo pistons
Callies compstar Rods
arp bolts
callies crank
FED ported ls3 heads

cam 232-238 112lsa +4adv .629 lift. I questioned that with my stock converter and then they switched to 222-235 120lsa +4 adv .595 lift. (would this cam maybe hold too much pressure causing pump gas issues)?

They stated 10.5:1 comp ratio which I fear may be a little high??

I'm in Canada. These guys are a long way away and my $ is worth shit there now.
Many variables.
$12800 usd plus shipping taxes etc , probably 21k CAD once it's said and done, Then I still need to think about the blower, get an oil pan and other misc parts to put it together.

With my 1.9l blower needing work it should probably be rebuilt with new rotors and get ported while we're at it.
Maybe instead of spending thousands on that I may be better just to spend a little more and get a heartbeat or something?

I'm trying not to fall in the rabbit hole as I want a good driving car I can put miles on.

Where I'm at now is to concentrate on a larger displacement, well built bottom end and I can always upgrade heads and crank up boost later if I feel the need.
I'm really not sure.

I was hoping to keep it around 20k CAD but it's looking like that may not happen.

I'm no mechanical dummy but I have a lot to learn in this realm. I appreciate everything I've learned while sorting through threads on this forum and the wealth of knowledge that is passed around here. Thanks for that.

If it were you and you were starting from scratch what would you do? .......No. Twin turbos are too expensive lol.
 

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Fun pedal, Few doors
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Folks who are far more versed in this will weigh in and point you in the right direction, but I'll throw in my thoughts on a couple of general points:
  • the B15 is a great choice IF (ONLY if) you want a warranty, ~stock output~ and you DON"T plan to mod it.
  • Building your own is they way to go for your kind of target.
  • There's a lot to recommend investing in a six-bolt build but you'll need to weigh the cost on going that route ($$/peace of mind) and that is more important the further you get from stock HP... but even at stock levels, it is still a valid consideration.
  • There is a similar argument to support upgrading crank and rods above the entry-level pieces that are typically quoted
  • There is, In my opinion, a somewhat vague "line in the sand" that exists around 800-850 rwHP; if your target gets over that range, costs go up exponentially because EVERYTHING has to be upgraded to achieve the big numbers AND to be able to handle that output and live a long happy life.
  • Read my sig line...
  • Get with Matt @Lt1z for the real experienced low-down
  • Have FUN!
 

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Just buy a new GM blower, 376.
 
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2011 A6 black diamond sedan.
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Discussion Starter · #4 ·
Just buy a new GM blower, 376.
You're referring to the stock 1.9l blower?
I looked at that.
I'd be into it about $3600 CAD with a ZL1 lid and Brick included (my brick also got poked)
and then I would possibly still consider porting while it's apart.

Folks who are far more versed in this will weigh in and point you in the right direction, but I'll throw in my thoughts on a couple of general points:
  • the B15 is a great choice IF (ONLY if) you want a warranty, ~stock output~ and you DON"T plan to mod it.
  • Building your own is they way to go for your kind of target.
  • There's a lot to recommend investing in a six-bolt build but you'll need to weigh the cost on going that route ($$/peace of mind) and that is more important the further you get from stock HP... but even at stock levels, it is still a valid consideration.
  • There is a similar argument to support upgrading crank and rods above the entry-level pieces that are typically quoted
  • There is, In my opinion, a somewhat vague "line in the sand" that exists around 800-850 rwHP; if your target gets over that range, costs go up exponentially because EVERYTHING has to be upgraded to achieve the big numbers AND to be able to handle that output and live a long happy life.
  • Read my sig line...
  • Get with Matt @Lt1z for the real experienced low-down
  • Have FUN!
I appreciate your input @MrSurly
I've read your build thread and am trying my best to learn from that and not to get in too deep. I won't be going to shoot for 1/4 mile times or anything. Just some tire peeling fun and a nice comfy powerful car to drive.
I see the line in the sand and plan to stay below the 800-850 range (even in the future) If I did decide to add more than that later, then at that point it might just be a "fuckit. Run er till she blows" scenario and start again. lol
I look forward to learning more from the likes of @Lt1z and have my mind blown by reading more @rubberduck posts.
 

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2011 A6 black diamond sedan.
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Discussion Starter · #6 ·
I'm still reading and learning.
I learned a lot on this thread similar Thread
I fear a built up LSX block or Next may end up out of my financial comfort range.
I'm unsure about the durability of the sleeved LS3 block
Is a 6.0l based block a good option to build from? If so what are the pros and cons?
 

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2011 Thunder grey coupe auto
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With the same issues of only 91 I’m in similar situation. That was my concern with adding meth for more power is now my tune was reliant on it unless I was only using to cool the charge . My car is tuned so if I’m traveling all I have to worry about is getting 91 . Some local motorsports shops sell gulf e85 in 5 gallon and drums so I have a Dsx auxiliary pump 1050x injectors and sensors and can add that if I want to go out to play but keep reliability on pump . Not the cheapest option but safe enough for me .
 

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I'm still reading and learning.
I learned a lot on this thread similar Thread
I fear a built up LSX block or Next may end up out of my financial comfort range.
I'm unsure about the durability of the sleeved LS3 block
Is a 6.0l based block a good option to build from? If so what are the pros and cons?
What kind of power are you looking to make?
 

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2011 A6 black diamond sedan.
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Discussion Starter · #9 ·
What kind of power are you looking to make?
.I want something that will run on 91 octane, make decent power 6-700 at the wheels. Maybe more with meth inj?
With the same issues of only 91 I’m in similar situation. That was my concern with adding meth for more power is now my tune was reliant on it unless I was only using to cool the charge . My car is tuned so if I’m traveling all I have to worry about is getting 91 . Some local motorsports shops sell gulf e85 in 5 gallon and drums so I have a Dsx auxiliary pump 1050x injectors and sensors and can add that if I want to go out to play but keep reliability on pump . Not the cheapest option but safe enough for me .
I think if I was to spray meth it would be for insurance. I don't know a lot about it "yet" though.
No E85 here.
I think I'll put an aux pump in while it's down though and I guess it depends on where I end up with the engine whether the 850 injectors will suffice or not.
 

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I’m not sure at what point you’d need to add auxiliary pump if not running e but if you do look up alm fuel hat . He’s a member on here . He adds a port on his billet fuel hat instead of drilling and tapping fuel tank . Also addresses the common stock fuel hat elbow leak .
 

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Discussion Starter · #12 ·
You dont need to worry about the block at that level. It will be fine
At what point would I worry? (in case of future adds)
my current block wasn't ok but I think that may be related to pistons more than block.
 
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600-700 whp on pump gas is totally doable on a mildly built LSA. You're overthinking it. If you start increasing compression ratio it's not going to like running on 91 and will be a lot less tolerant to environmental changes or any tuning that isn't exactly on the money.
 

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Theirs actually some stations in Ontario that has 94 Octane.
But Meth injection should be on your list.
A forged piston/rod stock crank will handle 600-650RWHP all day mild cam,10-12 psi of boost, 91 w/meth.
We have one that is at 880RWHP and it did a few 1 mile events and survived with no issues.But it's at the limit.We have another street car(Camaro) with 1100rwhp(91 and meth) that we use mostly for 1 mile runs, that one we had to go with the LSX block,6 bolt heads,and all the other good stuff to survived.
So be honest with your goal and budget,make a plan and stick with it.
 

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Yes, just get a factory 1.9, port it if you would like. Your goals are easily doable with the factory stuff.

My build,
Stock LSA shortblock factory compression
Gmpp cnc ls3 heads
Ported stock blower
Matt’s, Lt1z 2.5 cam
2.4 and 8.6 pullies
T56 magnum

I made 750 of both at the rear wheels and I’m sure the tune wasn’t optimized, on E85 maybe 60%.
Cloud Sky Mesh Building Rectangle
 

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Discussion Starter · #17 ·
Thanks for all the input. Maybe I'll just keep it simple and wait for the LSX376b-15. I see some places have January ETA dates, so it might actually ship.
Maybe I'll just add a new 1.9 blower blower to the order also.
 

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At what point would I worry? (in case of future adds)
my current block wasn't ok but I think that may be related to pistons more than block.
What type of piston damage did you encounter?
 

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Discussion Starter · #19 · (Edited)
What type of piston damage did you encounter?
This is what came out with my starter.
All the pics are in my intro thread though. here

While I have your attention Mr. @Rubber Duck . In you opinion, could it be beneficial to upgrade the cam in the LSX376b15 to make it more tolerable to 91 octane gas by reducing dynamic compression without losing power?

Gas Auto part Cylinder Metal Titanium
 

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This is what came out with my starter.
All the pics are in my intro thread though. here

While I have your attention Mr. @Rubber Duck . In you opinion, could it be beneficial to upgrade the cam in the LSX376b15 to make it more tolerable to 91 octane gas by reducing dynamic compression without losing power?

View attachment 163178
Oh Yes, I remember that thread now..:giggle:
And you did a very nice job, regarding destroying that engine..:eek:

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

Regarding your camshaft question. .
Yes, that can be done.

However, accurately calculating that with a roots blower, which is very sensitive to heat, versus the 'average density ratio' seen at the output of the intercooler, could be a difficult task.

Also, generally speaking; all of the OEM Camshafts, are meant
to 'retain cylinder pressure', so as to maximize torque.

They are not meant to provide for 'Peak HP', nor is the
too small of a TB these engines are equipped with.

How about you simply reduce your pulley ratio a bit, or use an octane booster. . . .

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

-roots blowers are highly inefficient-
And these 'Stock Roots Blowers' don't like filling the cylinders,
much more than 100% fill, and they then generate much heat.

This then causes the density to go down, and the
quality of the fuel then becomes an issue.

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

A 1900 CC Roots Blower, is equal to 116 CID.
Your running a pulley ratio of 3.62.

If we multiply those together, then the 'Equivalent CID' would be
the product of the two, and amounts to (116 * 3.62)= 420 CID.

Also, at ~6200 rpm, your blower is also spinning ~22,440 rpm.

And if we divide 420 by 376, we get a volume ratio of ~1.11.
You might desire to reduce that down, just a bit..;)

Good Luck!
 
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