Forced Induction Superchargers | Turbochargers | Intercoolers

Cam question on current combo...

Thread Tools
 
Search this Thread
 
Old Mar 25, 2006 | 05:17 PM
  #1  
67Firebird455's Avatar
Thread Starter
12 Second Club
20 Year Member
Photogenic
Photoriffic
Liked
iTrader: (27)
 
Joined: Sep 2004
Posts: 2,552
Likes: 12
From: Visalia, California
Default Cam question on current combo...

Running 6-8# currently, kept the hot cam i had in it when it was NA, seems to run excellent, and recently purchased a set of #317 6.0l heads and looking at another block to build a low-comp shortblock, but anyway... I know turbocharging "requires" a reverse/split cam for maximum efficiency... how much would you say I'm loosing by allowing boost out the exhaust? Experienced users, please give me your opinions and suggestions!
Reply
Old Mar 25, 2006 | 06:45 PM
  #2  
engineermike's Avatar
TECH Addict
 
Joined: Jul 2005
Posts: 2,153
Likes: 3
Default

Originally Posted by 67Firebird455
. . .I know turbocharging "requires" a reverse/split cam for maximum efficiency... how much would you say I'm loosing by allowing boost out the exhaust?
Reverse split turbo cams are way over-rated. There are very few back-to-back dyno tests available, but in the testing I've seen a single pattern or regular split makes as much or more power. The Hot Cam will be fine at "low" boost levels, and okay for higher ones.
Reply
Old Mar 25, 2006 | 08:24 PM
  #3  
67Firebird455's Avatar
Thread Starter
12 Second Club
20 Year Member
Photogenic
Photoriffic
Liked
iTrader: (27)
 
Joined: Sep 2004
Posts: 2,552
Likes: 12
From: Visalia, California
Default

I also thought it was over-rated, but... My friend just got back from getting his Z dyno-tuned and he's running about 9:1 with 11-12# through an auto with 3.73's and they got an extra 60rwhp out of it, but still only just over 400 rwhp/tq. They removed the MAF and 2 bar MAP apparently, I really don't understand that, but his numbers are dang low, and he's running a Z06 cam (less overlap than mine). What do you guys think?

PS - The guys at the speed shop said his turbo was done "blowing" at around 5200 rpm where the hp would fall off. He's got a 1-bar spring in the WG, and ocassionally gets 12# out of it, nothing more, his reference is up front, turbo in the back.

I don't want to show up and be disappointed as hell with my setup running 7-8# and only making 400rwhp.
Reply
Old Mar 26, 2006 | 02:50 AM
  #4  
DeltaT's Avatar
TECH Addict
iTrader: (5)
 
Joined: Jun 2005
Posts: 2,404
Likes: 1
Default

Did they replace the 2-bar with a 3-bar? Nothing else makes sense. You need a MAF or a MAP or some other metering device.

What speed shop ar you dealing with? I'm in Santa Clara.

There's a lot of people out there that knew cars when they were carbs and know jack about EFI or boost or tuning.

Jim
Reply
Old Mar 26, 2006 | 02:31 PM
  #5  
67Firebird455's Avatar
Thread Starter
12 Second Club
20 Year Member
Photogenic
Photoriffic
Liked
iTrader: (27)
 
Joined: Sep 2004
Posts: 2,552
Likes: 12
From: Visalia, California
Default

I'll have to find out what shop it is, I know it's in Roseville, and the guy has no signs out front and spent 12 hours on the car. They supposedly eliminated the MAF altogether, but only 410rwhp at that much boost? Personally, I'll be heading to Synergy next month to have mine done. I need to know what I'm going to need when I go to Fremont. My buddy spent $1400 with all the work done, including have a catch can installed, seems a little high, but as long as he's happy. I'm just so confused about this...
Reply
Old Mar 26, 2006 | 07:38 PM
  #6  
engineermike's Avatar
TECH Addict
 
Joined: Jul 2005
Posts: 2,153
Likes: 3
Default

It's not the cam's fault.
Reply
Old Mar 26, 2006 | 07:53 PM
  #7  
67Firebird455's Avatar
Thread Starter
12 Second Club
20 Year Member
Photogenic
Photoriffic
Liked
iTrader: (27)
 
Joined: Sep 2004
Posts: 2,552
Likes: 12
From: Visalia, California
Default

Kinda figured that... one guy said it was the cam, the owner (force fed performance) in Sacramento said his turbo was done blowing early. Doesn't surprise me, that thing spools instantly.
Reply
Old Mar 26, 2006 | 07:58 PM
  #8  
Pro Stock John's Avatar
LS1Tech Co-Founder
20 Year Member
Community Influencer
iTrader: (34)
 
Joined: Nov 2001
Posts: 45,341
Likes: 1,770
From: Chicago, IL
Default

Dyno it and tell us how it does. Maybe we can use your hotcam dyno sheet and look at what happens to the power.

Personally, I was told to go single pattern or reverse split by someone who I highly respect in the LSx FI field, so that is what my decision is based on.
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
Old Mar 26, 2006 | 08:24 PM
  #9  
67Firebird455's Avatar
Thread Starter
12 Second Club
20 Year Member
Photogenic
Photoriffic
Liked
iTrader: (27)
 
Joined: Sep 2004
Posts: 2,552
Likes: 12
From: Visalia, California
Default

John, I also agree with you. My new motor will have a reverse split for torque reasons (not going stroker) and I can't have it loping like it does, I'm in California, and you know how those **** smog officials/cops are. I just drive my TA on Saturday's or Sunday, drove it 50 miles today, big whoop. I messed with the BC today and it hit 10#, I was logging in EFI live, and didn't get any KR, kinda strange isn't it? My #317's should be here Wednesday, might put them on this 96k mile shortblock, let it live a LITTLE longer! =)
Reply




All times are GMT -5. The time now is 12:05 AM.

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