Tech / General Engine Is your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
Sponsored by:
Sponsored by: CARiD

nitrous cam for better gas mileage?

Thread Tools
 
Search this Thread
 
Old Aug 28, 2006 | 11:53 PM
  #1  
lilnach's Avatar
Thread Starter
Junior Member
 
Joined: Jul 2005
Posts: 15
Likes: 0
From: hawaii
Car: 92' Camaro
Engine: 350, ripped up, 383 soon
Transmission: 700r4
nitrous cam for better gas mileage?

I'm deciding on a cam for my 92 camaros 383. I want a hydraulic roller and about 230/236 dur @.050. I found a comp cam p/n 08-432-8 but it has a 110degree LSA. Can I put a nitrous cam with smilar specs but a 113degree LSA and get better gas milage? What else does LSA do?
Reply
Old Aug 29, 2006 | 12:28 PM
  #2  
Damon's Avatar
Supreme Member
 
Joined: Sep 1999
Posts: 7,072
Likes: 13
From: Philly, PA
Overlap is one thing that affects fuel economy. Spreading out the LSA decreases overlap and there's less unburnt air and fuel that could blow straight out the exhaust. But really, if you're talking about mileage, a smaller cam is what you want. Spreading out the LSA generally gives you a wider, less "peaky" powerband, but overall a lower one. It also smooths out the idle. It opens the exhaust sooner, possibly letting the cylinder "blow down" before it's really done giving all of it's energy to the crank. And lastly, it closes the intake valve later, which lowers your dynamic compression (cylinder pressure) and might lower combustion efficiency at low RPMs. But you're changing the basic breathing characteristics of your motor- it's not a change to consider lightly. And frankly, with all the puts and takes, you're talking about a small difference in economy.

If you want to get better bang for the buck, drop your durations by 10* across the board, leaving everything else the same, and you'll probably be a lot happier with the end result.
Reply
Old Aug 29, 2006 | 04:07 PM
  #3  
Air_Adam's Avatar
TGO Supporter
 
Joined: Oct 2002
Posts: 9,067
Likes: 1
From: Saskatoon, SK, Canada
Car: '83 Z28, '07 Charger SRT8
Engine: 454ci, 6.1 Hemi
Transmission: TH350, A5
Axle/Gears: 2.73 posi, 3.06 posi
Originally Posted by Damon
Overlap is one thing that affects fuel economy. Spreading out the LSA decreases overlap and there's less unburnt air and fuel that could blow straight out the exhaust. But really, if you're talking about mileage, a smaller cam is what you want. Spreading out the LSA generally gives you a wider, less "peaky" powerband, but overall a lower one. It also smooths out the idle. It opens the exhaust sooner, possibly letting the cylinder "blow down" before it's really done giving all of it's energy to the crank. And lastly, it closes the intake valve later, which lowers your dynamic compression (cylinder pressure) and might lower combustion efficiency at low RPMs. But you're changing the basic breathing characteristics of your motor- it's not a change to consider lightly. And frankly, with all the puts and takes, you're talking about a small difference in economy.

If you want to get better bang for the buck, drop your durations by 10* across the board, leaving everything else the same, and you'll probably be a lot happier with the end result.
Reply
Old Aug 30, 2006 | 03:12 AM
  #4  
lilnach's Avatar
Thread Starter
Junior Member
 
Joined: Jul 2005
Posts: 15
Likes: 0
From: hawaii
Car: 92' Camaro
Engine: 350, ripped up, 383 soon
Transmission: 700r4
Ok, so, how 'bout this-
how do ya'll think the original 110degree comp cam will run?
Reply
Old Aug 30, 2006 | 10:59 AM
  #5  
Damon's Avatar
Supreme Member
 
Joined: Sep 1999
Posts: 7,072
Likes: 13
From: Philly, PA
It'll run like a raped ape if you have half decent heads, intake and exhaust. It won't be great for mileage.
Reply
Old Aug 30, 2006 | 08:01 PM
  #6  
lilnach's Avatar
Thread Starter
Junior Member
 
Joined: Jul 2005
Posts: 15
Likes: 0
From: hawaii
Car: 92' Camaro
Engine: 350, ripped up, 383 soon
Transmission: 700r4
will it be streetable enough?
driving 10-15 miles to work everyday.
I got afr 195cc street heads
demon 750, eagle stroker forged rotating assembly
edel rpm air-gap intake
Reply
Old Aug 31, 2006 | 11:36 AM
  #7  
Damon's Avatar
Supreme Member
 
Joined: Sep 1999
Posts: 7,072
Likes: 13
From: Philly, PA
It'll be a little grumpy but nothing you can't put up with on a short commute. Mostly you're going to not like it when it's cold. Carbs, fairly large cams and a heat-isolated intake don't make for sparkling drivability on a cold engine. It'll be running super about the time you roll in the parking lot at your job.

If you're running an automatic trans you'll want a higher stall converter than stock, for sure (about 2500 at least, give or take). Not just to let the motor get into it's powerband when you're launching hard off the line but also becuase it takes a lot of the load off the motor at idle in-gear. Otherwise you'll be 2-footing it at every stoplight. A manual trans car wouldn't have to worry about this, obviously, but you'll still find you need to get some RPMs going before you let the clutch out to pull away from a stop.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Azrael91966669
DIY PROM
25
Jun 20, 2017 04:04 AM
Orr89RocZ
Power Adders
206
Apr 25, 2016 08:28 AM
InfinityShade
Transmissions and Drivetrain
15
Aug 22, 2015 08:00 PM
86White_T/A305
LTX and LSX
0
Aug 17, 2015 12:16 AM
355tpipickup
Tech / General Engine
3
Aug 13, 2015 07:35 AM




All times are GMT -5. The time now is 05:57 PM.