INTERNAL ENGINE MODIFICATIONS Valvetrain |Heads | Strokers | Design | Assembly

What are everyone's thoughts on big cams and loss of low end?

Thread Tools
 
Search this Thread
 
Old Jul 19, 2009 | 04:50 PM
  #1  
RandomHero's Avatar
Thread Starter
TECH Veteran
iTrader: (24)
 
Joined: Jun 2005
Posts: 4,787
Likes: 1
From: Austin,TX Name:Mark
Default What are everyone's thoughts on big cams and loss of low end?

Speaking from experience my 224/224 on a 112 lsa LOST low end power over stock.

I was getting into a debate with a guy on another forum and figured I'd ask you guys' opinions on the matter.

Basically my theory is that USUALLY as duration increases the powerband is SHIFTED rather than INCREASED.

The guy I was discussing this with was arguing that with a big cam you just don't lose any low end power and the gains up top mask the minimal gains of low end power/torque.

So if anyone has any dyno graphs or proof one way or another I'd be very interested to see.

Like I said, speaking from experience I lost a ton of low end power to where I couldn't even spin the tires.

EDIT-I'm also speaking strictly in regards to bigger cams. A 212/218 isn't going to prove a point one way or another.
Reply
Old Jul 19, 2009 | 04:57 PM
  #2  
Mr. Sandog's Avatar
TECH Veteran
 
Joined: Mar 2004
Posts: 4,632
Likes: 2
From: Sun Diego
Default

The way I understand it, changes in duration shift the powerband up or down (an increase in duration shifts the powerband up, a decrease in duration shifts the powerband down).

Now shifts in the LSA are what affect the width of the powerband - increase the LSA (i.e. from 110 to 118) and this will widen your powerband. Decrease the LSA (i.e. from 116 to 109) and you will narrow your powerband and the power will feel more 'peaky.'
Reply
Old Jul 19, 2009 | 08:56 PM
  #3  
Ad1's Avatar
Ad1
On The Tree
 
Joined: Mar 2009
Posts: 148
Likes: 1
From: UAE, AD
Default

the cam i have now which is 210/218 112lsa killed my low end it wont have the power until at least 3k rpm , so u must have converter to be in the cam range
Reply
Old Jul 19, 2009 | 09:03 PM
  #4  
RandomHero's Avatar
Thread Starter
TECH Veteran
iTrader: (24)
 
Joined: Jun 2005
Posts: 4,787
Likes: 1
From: Austin,TX Name:Mark
Default

Originally Posted by Ad1
the cam i have now which is 210/218 112lsa killed my low end it wont have the power until at least 3k rpm , so u must have converter to be in the cam range
I'm looking more for dyno graphs or scientific proof, but thanks for the input.
Reply
Old Jul 19, 2009 | 09:17 PM
  #5  
dirt track racer 81's Avatar
TECH Senior Member
iTrader: (45)
 
Joined: Jun 2005
Posts: 9,439
Likes: 13
From: Hennessey, Oklahoma
Default

i know it aint much but this graph is 379.9 hp at 6800 and 310 tq at around 5000 with 243s milled .030 and vic jr with a 1375cfm 4150 plate, cam is in my sig. my old 230/226 made 325 at 6000 and 320 tq that was with a 85mm pro prod intake and 241 heads..both runs were made in 2nd gear you can see in the graph that the converter is very loose and flashes to 4500 what i made in the top end overpowers the 10 hp i lost down low.
Reply
Old Jul 19, 2009 | 09:20 PM
  #6  
RandomHero's Avatar
Thread Starter
TECH Veteran
iTrader: (24)
 
Joined: Jun 2005
Posts: 4,787
Likes: 1
From: Austin,TX Name:Mark
Default

Better than nothing. It's the best I've seen so far. Thanks Tyler. I would love to be able to find a before and after dyno of a bigass cam in an lsx motor.

Thanks again.
Reply
Old Jul 19, 2009 | 09:28 PM
  #7  
dirt track racer 81's Avatar
TECH Senior Member
iTrader: (45)
 
Joined: Jun 2005
Posts: 9,439
Likes: 13
From: Hennessey, Oklahoma
Default

tomorrow i should be around town and ill go up and print off an old dyno run
Reply
Old Jul 19, 2009 | 09:30 PM
  #8  
RandomHero's Avatar
Thread Starter
TECH Veteran
iTrader: (24)
 
Joined: Jun 2005
Posts: 4,787
Likes: 1
From: Austin,TX Name:Mark
Default

Originally Posted by dirt track racer 81
tomorrow i should be around town and ill go up and print off an old dyno run
So would you agree that you sacrificed low-end or not?
Reply
Old Jul 19, 2009 | 09:32 PM
  #9  
Phantom's Avatar
11 Second Club
15 Year Member
iTrader: (16)
 
Joined: Sep 2006
Posts: 5,694
Likes: 50
From: The 405
Default

mark you know i've had some massive cams...tyler has done the tuning. we've never felt dramatic lowend loss...maybe he's just a badass tuner i dunno
Reply
Old Jul 19, 2009 | 09:33 PM
  #10  
dirt track racer 81's Avatar
TECH Senior Member
iTrader: (45)
 
Joined: Jun 2005
Posts: 9,439
Likes: 13
From: Hennessey, Oklahoma
Default

it lost some on the dyno yes, seat of the pants no..i never go to the track im always on the street.. i cant even floor it below 40..
Reply



All times are GMT -5. The time now is 02:41 AM.