Generation IV Internal Engine 2005-2014 LS2 | LS3 | LS7 | L92 | LS9

4/7 swap? --Stupid question?

Thread Tools
 
Search this Thread
 
Old 02-19-2006, 10:04 AM
  #1  
TECH Veteran
Thread Starter
iTrader: (14)
 
bayer-z28's Avatar
 
Join Date: Apr 2005
Location: N. Falmouth MA
Posts: 4,085
Likes: 0
Received 0 Likes on 0 Posts

Default 4/7 swap? --Stupid question?

Ok, I know that magazines are not allways the greatest places to go for info. But I read them anyway. I've reently read an article in Hot Rod about swappign the firing order to get more power.

seeing as the LS1 Firing order is... 1-8-7-2-6-5-4-3... you take the accompaying cyl..(sp?) in relation to the cycles...

1-8-7-2
6-5-4-3
I-C-P-E

The power stroke on 4/7 are opposite. You swap them and it supposedly gains about 10hp. Seeing as the cam determines the firing order.

Am I insane?
Old 02-19-2006, 10:38 AM
  #2  
TECH Enthusiast
iTrader: (16)
 
67Ranger's Avatar
 
Join Date: Aug 2005
Location: San Antonio, TX
Posts: 655
Likes: 0
Received 0 Likes on 0 Posts

Default

sounds interesting... i'd like to see too
Old 02-19-2006, 11:42 AM
  #3  
TECH Addict
iTrader: (4)
 
Mike454SS's Avatar
 
Join Date: Oct 2004
Location: Manchester, CT
Posts: 2,139
Likes: 0
Received 3 Likes on 3 Posts

Default

Older smallblocks were 1-8-4-3-6-5-7-2...LS1 was the first small block where GM did the 4-7 AND 3-2 swap...go read about how many people tried 4-7 swaps on older smallblocks to get 10 HP...now they're saying to do it to an LS1 to put it back the other way...I find it kinda funny.
Old 02-19-2006, 11:44 AM
  #4  
11 Second Club
iTrader: (10)
 
-PEPE-'s Avatar
 
Join Date: Jun 2003
Posts: 2,298
Likes: 0
Received 0 Likes on 0 Posts

Default

Unless I'm just completely wrong here the LS engines have the 4/7 firing order already switched by GM when they designed that engine, the LT engines do not, so us LT guys do custom 4/7 grinds. That issue was one of the first side by side comparisons of identical cams in the same identical engine (great article), other research I've done on it was just builders stating it's good for 10hp but little actual proof like a dyno sheet and (no other changes) being made to get a true benchmark. The gains for most on average are not necessarily a full 10 hp, some gains are as little as 2-4 hp. But it costs such a small amount to go ahead and do the swap.

Last edited by BRETTINATOR; 02-21-2006 at 12:36 AM.
Old 02-19-2006, 09:07 PM
  #5  
427
TECH Junkie
iTrader: (3)
 
427's Avatar
 
Join Date: May 2003
Location: Clayton, North Carolina
Posts: 3,898
Likes: 0
Received 6 Likes on 6 Posts

Default

The LS series engine already has the preffered order.


Kurt



Quick Reply: 4/7 swap? --Stupid question?



All times are GMT -5. The time now is 12:44 AM.