Forced Induction Superchargers | Turbochargers | Intercoolers

under powered?

Old Sep 22, 2008 | 10:42 PM
  #1  
hawk584's Avatar
Thread Starter
TECH Fanatic
15 Year Member
Liked
Loved
Community Favorite
iTrader: (1)
 
Joined: May 2006
Posts: 1,786
Likes: 43
From: earth
Default under powered?

http://i33.photobucket.com/albums/d7...awk584/001.jpg

i've been wondering for a little while now...

forged 385ci LT1 w/stock intake manifold & TB, LEP custom turbo cam
9:1 compression
t67 STS 10psi
intercooled
tuned by pcm4less( whom i dont have any issues with i think they did an awesome job)
Reply
Old Sep 22, 2008 | 10:56 PM
  #2  
borninatransam's Avatar
TECH Regular
iTrader: (4)
 
Joined: Mar 2004
Posts: 483
Likes: 0
From: GSO
Default

What kind of cam? And I don't doubt Alvin's tuning abilities but if this tune wasn't done on the road or at least on a dyno it's just not the same.
Reply
Old Sep 22, 2008 | 11:00 PM
  #3  
hawk584's Avatar
Thread Starter
TECH Fanatic
15 Year Member
Liked
Loved
Community Favorite
iTrader: (1)
 
Joined: May 2006
Posts: 1,786
Likes: 43
From: earth
Default

i was asked not to give out the cam specs and I'd like to respect his wishes. it's only be tuned once so maybe it could be in need of a touch up tune and added boost? i just find it odd that i'm only putting down about 50 more hp's then an all motor 385... maybe he played it safe for the first tune and amount of boost to let the newly built motor break in

Last edited by hawk584; Sep 22, 2008 at 11:08 PM.
Reply
Old Sep 22, 2008 | 11:31 PM
  #4  
calongo_SS's Avatar
10 Second Club
iTrader: (7)
 
Joined: Feb 2004
Posts: 2,070
Likes: 1
From: Victoria, TX
Default

Looks like it falls off really early and falls off hard. It's peaking @ 4700 rpms???? Maybe you're floating the valves? I don't know enough about it to tell, maybe some one else will chime in.
Reply
Old Sep 22, 2008 | 11:40 PM
  #5  
Zombie's Avatar
10 Second Club
iTrader: (2)
 
Joined: May 2004
Posts: 2,498
Likes: 4
From: Las Vegas
Default

If the boost isn't dropping off after it peaks, it looks like it could be valve float, what is the spring pressure?
Reply
Old Sep 22, 2008 | 11:52 PM
  #6  
borninatransam's Avatar
TECH Regular
iTrader: (4)
 
Joined: Mar 2004
Posts: 483
Likes: 0
From: GSO
Default

If the motor was built correctly the only break it needs is a couple heat cycles. Was this done on or off the dyno? If it was bench top tuned then I don't see where you could be hitting the tune spot on. Again not doubting the abilities of the tuner it's just from my experience dyno or street tuning is the only way to get the car where it needs to be. Where are you located? I'm sure there's at least one tuner close to where you live.
Reply
Old Sep 22, 2008 | 11:52 PM
  #7  
RW99's Avatar
TECH Resident
 
Joined: Jan 2004
Posts: 832
Likes: 0
From: Castro Valley, CA
Default

Your turbo almost looks like a centrifugal blower by its dyno sheet. Where's the boost? In order to troubleshoot your problem, please list as much supporting info as possible. Include your A/R on the T67, and tell us about the boost trace for these pulls. Is this a new install? Or a retune? Isn't a T67 almost too small for 385 ci? I would think that it's way off of its "happy zone" on the compressor map at 10 psi for that many cubes...

I run a front-mount T67 0.96 A/R on a 346 at 11 psi and that's pretty much its limit.
Reply
Old Sep 23, 2008 | 04:22 AM
  #8  
87silverbullet's Avatar
TECH Veteran
iTrader: (11)
 
Joined: Mar 2007
Posts: 4,873
Likes: 8
From: Slidell,LA
Default

Unless I missed it you don't state what heads either. I second that you don't have a big enough turbo for that motor
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

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

 Verdad Gallardo
story-1

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

 Pouria Savadkouei
story-2

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

 Verdad Gallardo
story-3

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-4

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-5

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-6

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

 Verdad Gallardo
story-7

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-8

10 Camaros You Should Never Buy

 
story-9

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo


Thread Tools
Search this Thread

All times are GMT -5. The time now is 03:42 PM.

story-0
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-1
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-2
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-3
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-4
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-5
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-6
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
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE