Forced Induction Superchargers | Turbochargers | Intercoolers

Boost on 11.5:1 Compression

Thread Tools
 
Search this Thread
 
Old Feb 11, 2019 | 10:46 AM
  #1  
98RedBird's Avatar
Thread Starter
TECH Addict
iTrader: (77)
 
Joined: May 2005
Posts: 2,773
Likes: 3
From: Peoria, IL
Default Boost on 11.5:1 Compression

Having a 416 LS3 built by one of our sponsors. Set it up with -8cc pistons and TFS 245's.

The builder mentioned that I should be fine on 93 octane up to about 7 psi or so of boost, more with E85.

I didn't realize that I could run boost at all on this motor given the compression ratio. What do you guys think? I wasn't planning on boost, but the idea does interest me a little bit down the line. Just curious what you guys' opinions were.

How much would 7 psi net on that larger CI motor? 700-800 to the tire?

Again, no plans just curious.
Reply
Old Feb 11, 2019 | 12:06 PM
  #2  
JoeNova's Avatar
Restricted User
 
Joined: Mar 2014
Posts: 7,192
Likes: 109
From: Ohio
Default

7-8 PSI is roughly a 35-50% increase in power depending on a few factors.
You could get away with 93 and meth on 11.5:1 with low boost.
Reply
Old Feb 11, 2019 | 12:38 PM
  #3  
TPIZ92's Avatar
TECH Regular
15 Year Member
Photogenic
Photoriffic
Liked
iTrader: (10)
 
Joined: Oct 2006
Posts: 444
Likes: 4
From: Long Island, NY
Default

I find just posting whst people get away with helps put things into perspective...

My compression is no where near you but i can give you an idea of what i see. Stock ls1 compression (stock engine) i see 6psi..ish. with about a steady 16.5 degrees of spark on 93 with intake temps around 175 and no intercooler from a powerdyne. On e50-60 i have stock ls1 timing (24-25) in it with the same boost with no detonation at all. I love e50.
Reply
Old Feb 12, 2019 | 09:20 AM
  #4  
fif_gen_powa's Avatar
Staging Lane
 
Joined: Mar 2015
Posts: 79
Likes: 2
Default

e85 - yes, I run the stock ls3 10.7:1 and have seen as high as 20psi on e85 and meth

I wouldn't bother with pump gas you will be on the edge all the time and one bad tank of gas could be all it takes to be catastrophic
Reply
Old Feb 13, 2019 | 03:56 PM
  #5  
Detoxx03's Avatar
10 Second Club
iTrader: (14)
 
Joined: Jan 2007
Posts: 7,336
Likes: 74
From: Woodward Avenue
Default

Don’t bother with 93. Run the corn and enjoy it.
Reply
Old Feb 14, 2019 | 01:24 AM
  #6  
gametech's Avatar
TECH Veteran
20 Year Member
Active Streak: 30 Days
Active Streak: 60 Days
Top Answer: 1
iTrader: (1)
 
Joined: Sep 2004
Posts: 4,915
Likes: 908
From: Stockbridge GA
Default

Originally Posted by fif_gen_powa
e85 - yes, I run the stock ls3 10.7:1 and have seen as high as 20psi on e85 and meth

I wouldn't bother with pump gas you will be on the edge all the time and one bad tank of gas could be all it takes to be catastrophic
Exactly. Unless you are boost limited by a racing class, there is no need to push things to the edge all the time. Some (a lot) of what you see people getting away with on here involves near perfect tunes that they are always working on.
Reply
Old Feb 21, 2019 | 10:42 AM
  #7  
fastvet's Avatar
11 Second Club
iTrader: (2)
 
Joined: Dec 2007
Posts: 588
Likes: 0
From: !!!!TEXAS!!!!
Default

Run Methanol. I run it on a Stock LS3 pushing about 12.5lbs of boost with a separate container holding methanol. the methonal is only sprayed at certain boost levels. get with East coast supercharging. they have good kits and dual nozzle kits. They can explain it a bit better. But yes, you can run boost at that level with proper octane.
Reply
Old Feb 21, 2019 | 11:48 AM
  #8  
AnotherWs6's Avatar
TECH Addict
iTrader: (17)
 
Joined: Sep 2012
Posts: 2,670
Likes: 38
From: Westchester, NY
Default

Use meth. Not on your motor, but personally. Wont be long before you dont care about the engine.


This was a joke.
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

 Pouria Savadkouei
story-1

Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

 Verdad Gallardo
story-2

7 Most Reliable High-Performance Engines GM Has Ever Built

 Verdad Gallardo
story-3

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-4

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-5

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-6

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-7

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-8

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-9

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
Old Feb 21, 2019 | 04:26 PM
  #9  
joyridin''s Avatar
TECH Enthusiast
10 Year Member
iTrader: (1)
 
Joined: Jan 2014
Posts: 628
Likes: 36
Default

Originally Posted by AnotherWs6
Use meth. Not on your motor, but personally. Wont be long before you dont care about the engine.


This was a joke.
SMH...yeah...that was a good one!
Reply
Old Feb 21, 2019 | 04:28 PM
  #10  
joyridin''s Avatar
TECH Enthusiast
10 Year Member
iTrader: (1)
 
Joined: Jan 2014
Posts: 628
Likes: 36
Default

Originally Posted by fastvet
Run Methanol. I run it on a Stock LS3 pushing about 12.5lbs of boost with a separate container holding methanol. the methonal is only sprayed at certain boost levels. get with East coast supercharging. they have good kits and dual nozzle kits. They can explain it a bit better. But yes, you can run boost at that level with proper octane.
Stock LS3? No aftermarket cam or anything? Got any rough idea of what horsepower you are seeing? My engine is stock except a cam/headers and I was going to drop on a Supercharger but was a little worried about the 10.75 CR.
Reply
Old Feb 21, 2019 | 04:32 PM
  #11  
pdxmotorhead's Avatar
TECH Addict
5 Year Member
 
Joined: Oct 2016
Posts: 2,513
Likes: 480
From: PDX-OR-USA
Default

One advantage,, of Ethanol over methanol is that its Way less corrosive to Aluminum.
The Octane and burn are very close,, You can run E85 on the street, and bump to E100 if your local distributor is cooperative..

If your just using supplemental injection Ethanol works just fine in place of methanol. (With the correct tune.. ) and its about 1/2 the price if you have a pump source.. I've purchased it at big chemical distributors,, but they often require a 50GAL drum purchase..
Reply
Old Feb 21, 2019 | 11:32 PM
  #12  
Detoxx03's Avatar
10 Second Club
iTrader: (14)
 
Joined: Jan 2007
Posts: 7,336
Likes: 74
From: Woodward Avenue
Default

Originally Posted by joyridin'
Stock LS3? No aftermarket cam or anything? Got any rough idea of what horsepower you are seeing? My engine is stock except a cam/headers and I was going to drop on a Supercharger but was a little worried about the 10.75 CR.
Nothing to worry about with a good tune and proper octane. Stock LS3 here at 980rwhp.
Reply
Old Feb 22, 2019 | 05:21 PM
  #13  
C5_Pete's Avatar
10 Second Club
15 Year Member
Liked
Loved
Community Favorite
iTrader: (8)
 
Joined: Dec 2008
Posts: 983
Likes: 361
From: Washington TWP, NJ
Default

Originally Posted by Detoxx03
Don’t bother with 93. Run the corn and enjoy it.
^^^ This right here... If you have access to E, then use it.

My buddy has a forged internals LSA block 377" on E at 11:1CR. He street drives it everywhere and has more passes than I can remember. 25+PSI with a YSi. It's in a C5Z. He's run 158 so far still tuning.
Reply
Old Feb 25, 2019 | 02:15 PM
  #14  
fastvet's Avatar
11 Second Club
iTrader: (2)
 
Joined: Dec 2007
Posts: 588
Likes: 0
From: !!!!TEXAS!!!!
Default

Originally Posted by joyridin'
Stock LS3? No aftermarket cam or anything? Got any rough idea of what horsepower you are seeing? My engine is stock except a cam/headers and I was going to drop on a Supercharger but was a little worried about the 10.75 CR.
I'm hitting 652RWHP on a conservative tune in a 6l80 transmission dyno'd in 3rd gear. Bone stock motor

Don't mind my signature block. that was my old setup in the C5 not the C6. I just haven't been on here that much lately
Reply
Old Mar 3, 2019 | 09:14 AM
  #15  
joyridin''s Avatar
TECH Enthusiast
10 Year Member
iTrader: (1)
 
Joined: Jan 2014
Posts: 628
Likes: 36
Default

Originally Posted by fastvet
I'm hitting 652RWHP on a conservative tune in a 6l80 transmission dyno'd in 3rd gear. Bone stock motor

Don't mind my signature block. that was my old setup in the C5 not the C6. I just haven't been on here that much lately
What cam are you running? Looking at different manufacturers, they seem to be all over the map for a supercharged positive displacement camshaft. If you don't mind, what psi are you running?
Reply
Old Mar 7, 2019 | 01:32 PM
  #16  
fastvet's Avatar
11 Second Club
iTrader: (2)
 
Joined: Dec 2007
Posts: 588
Likes: 0
From: !!!!TEXAS!!!!
Default

Originally Posted by joyridin'
What cam are you running? Looking at different manufacturers, they seem to be all over the map for a supercharged positive displacement camshaft. If you don't mind, what psi are you running?
I'm Bone stock on the motor. Only thing I have done to the car is ECS Supercharger, LT Headers with x-pipe, no cats, borla exhaust, Methanol kit, hardened output shafts, and Yank SC3000 Converter. I believe the PSI is at around 12-12.5. Just go to east coast supercharging and you will see all these setups pushing this rwhp running low to mid 10's.
Reply




All times are GMT -5. The time now is 04:27 PM.

story-0
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

Slideshow: We take a close look at the ONE and Artidiag 800BT2 diagnostic tools from Topdon and the reasons to buy one over the other.

By Pouria Savadkouei | 2026-05-28 11:05:11


VIEW MORE
story-1
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

Slideshow: The controversial Ferrari F6 swaps its original flat-12 for a Corvette Z06-derived LT4 V8 and sends power to four rear wheels through a custom-built drivetrain.

By Verdad Gallardo | 2026-05-26 18:23:54


VIEW MORE
story-2
7 Most Reliable High-Performance Engines GM Has Ever Built

Slideshow:These GM engines didn't just make huge power, they survived abuse, boost, track days, and six-digit mileage with a reputation for refusing to quit.

By Verdad Gallardo | 2026-05-21 16:45:27


VIEW MORE
story-3
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-4
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-5
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-6
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-7
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-8
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-9
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE