[Z06] LS7 427ci to 440ci-HP/TQ INCREASE?
#1
Burning Brakes
Thread Starter
Member Since: Dec 2006
Posts: 958
Likes: 0
Received 0 Likes
on
0 Posts
LS7 427ci to 440ci-HP/TQ INCREASE?
Thinking of opening the engine and going the forged route. maybe swapping a 4.100" crank in there to up it to 440ci. will this be a noticable increase in hp/tq? or am i wasting my time/money?
#2
Drifting
Member Since: Dec 2006
Location: Down on the bayou La.
Posts: 1,665
Likes: 0
Received 1 Like
on
1 Post
Depends on what u want from the motor. U will gain seat-of-the pants torque, and u will see it on the dyno. If u are looking for even just 15 peak hp u won't find it. U will be impressed at the peak AVERAGE HP and how the torque looks. The cost will be the wall u hit around 6700rpm that tells u to shift 'cause the party is over for that gear. This only matters when u are trying to trap 150+ and all u have is 6800rpm and 3:42 gears. Unlike Ron Jeremy u will come up short. For a N/A street motor the 440-441 is tough to beat. My cranked out 589rw and just over 550ftlbs. I have seen dyno hp#s higher than mine, but I am torque king and would put my combo against ANY 427 rwhp dyno-queen at the track any day. I want to see what the LSXR manifold does for us.
#3
Melting Slicks
Member Since: Dec 2002
Location: Lone Star State
Posts: 2,898
Likes: 0
Received 0 Likes
on
0 Posts
#5
Safety Car
Depends on what u want from the motor. U will gain seat-of-the pants torque, and u will see it on the dyno. If u are looking for even just 15 peak hp u won't find it. U will be impressed at the peak AVERAGE HP and how the torque looks. The cost will be the wall u hit around 6700rpm that tells u to shift 'cause the party is over for that gear. This only matters when u are trying to trap 150+ and all u have is 6800rpm and 3:42 gears. Unlike Ron Jeremy u will come up short. For a N/A street motor the 440-441 is tough to beat. My cranked out 589rw and just over 550ftlbs. I have seen dyno hp#s higher than mine, but I am torque king and would put my combo against ANY 427 rwhp dyno-queen at the track any day. I want to see what the LSXR manifold does for us.
#7
Le Mans Master
We are doing one in a month or so. We are gonna do a 438 cu in that way we keep the same bore b/c its gonna be a nitrous motor. We are hopeing for 625rwhp.
#9
Le Mans Master
#10
Drifting
Member Since: Dec 2006
Location: Down on the bayou La.
Posts: 1,665
Likes: 0
Received 1 Like
on
1 Post
Thats going to be a tall order N/A w/ the stock intake, ported or not. Just watch the kpa at the top of your pulls on the 427s, it only gets worse. The LSXR should do better, at least over 600 rear wheel. That's more than any other "trusted" dyno run I have seen. If u don't need the last couple hundred rpms, it's worth doing when u forge the bottom end. IDK what anybody says. There is a limit however, too much stroke on the stock block and u start to run out of cyl. sleeve at the bottom, loosing control of the piston at BDC. On top of that, u can only put the wrist-pin so high (comp. hgt) and then u have to give up rod length to fit the stroke in (so much for 4.250 stroke stock blocks) and then u get a bad rod/stroke ratio. For u people there are tall-deck blocks
#11
Safety Car
I would like to do a 4.130" Bore and keep it the stock stroke eventually. I really like the 7K rpm range of the Z06 and think its one of it's favorable traits.
#13
What you want to do is within the realm of reasonability. Most folks see 615 peak RWHP (give or take 5-10 RWHP) with the setup you mention.
However, if there is ever any chance you'll put Nitrous or FI on the car, then keep the stroke where it is. Piston get's too darn small beyond the OEM 4" stroke for FI applications.
Perhaps you should consider forging the bottom end (maintaining OEM stroke), dropping the compression a little and going with some type of power adder - be it N20 or FI...?
However, if there is ever any chance you'll put Nitrous or FI on the car, then keep the stroke where it is. Piston get's too darn small beyond the OEM 4" stroke for FI applications.
Perhaps you should consider forging the bottom end (maintaining OEM stroke), dropping the compression a little and going with some type of power adder - be it N20 or FI...?
#14
Drifting
Member Since: Dec 2006
Location: Down on the bayou La.
Posts: 1,665
Likes: 0
Received 1 Like
on
1 Post
In my case, I used a piston for a 4" stroke w/ a 6.250 rod, then used a 4.125 stroke and a 6.192 rod to keep a healthy piston deck.Build the motor to run N/A and use N20 for the power-adder. I been doin' this for a while, it always works and for me, the LEAST maintenance per mile u can get having mega-power. Filling bottles sucks, but they will idle all day in 100deg heat and not complain, something not all F/I cars can do.
#15
Advanced
I made 603rwhp & 563rwtq with my LS7 440ci on 93 pump gas and its just a street car, 200 shot will be next
http://forums.corvetteforum.com/c5-t...idle-clip.html
http://forums.corvetteforum.com/c5-t...idle-clip.html
#16
Drifting
Member Since: Dec 2006
Location: Down on the bayou La.
Posts: 1,665
Likes: 0
Received 1 Like
on
1 Post
I made 603rwhp & 563rwtq with my LS7 440ci on 93 pump gas and its just a street car, 200 shot will be next
http://forums.corvetteforum.com/c5-t...idle-clip.html
http://forums.corvetteforum.com/c5-t...idle-clip.html
#17
Burning Brakes
I made 603rwhp & 563rwtq with my LS7 440ci on 93 pump gas and its just a street car, 200 shot will be next
http://forums.corvetteforum.com/c5-t...idle-clip.html
http://forums.corvetteforum.com/c5-t...idle-clip.html
I have a stoked block with a mildly aggressive cam - mainly for road course duty - but I drive it on the street as a daily driver when weather permits.
I am putting down 580rwhp/540rwtq.
#18
Advanced
Yes it is a pretty aggressive CAM shaft. When I started the project with Mike and Ron at Vengeance Racing we pulled out all the stops to make all the power that we could; the only stipulation I had was it had to run on 93 octane gas. I drive it on the street but you definately know you have an aggressive set up.
http://www.youtube.com/watch?v=voJ9sNN7Pnw
http://www.youtube.com/watch?v=voJ9sNN7Pnw
Last edited by EDS ZO6; 03-30-2009 at 03:31 PM.
#19
Burning Brakes
Yes it is a pretty aggressive CAM shaft. When I started the project with Mike and Ron at Vengeance Racing we pulled out all the stops to make all the power that we could; the only stipulation I had was it had to run on 93 octane gas. I drive it on the street but you definately know you have an aggressive set up.
http://www.youtube.com/watch?v=voJ9sNN7Pnw
http://www.youtube.com/watch?v=voJ9sNN7Pnw