427 build, LOW HP #s - LS1TECH



General LSX Automobile Discussion Non-technical LSX related topics.

427 build, LOW HP #s

Reply
 
Thread Tools Search this Thread
Old 11-11-2011, 04:27 PM   #1
On The Tree
Thread Starter
iTrader: (15)
 
Join Date: Mar 2006
Posts: 148
Default 427 build, LOW HP #s

So I just finished building my new motor and wasn't very happy with the hp numbers. On a mustang dyno it is putting down 430hp. Here is what the engine is:

427ci ls motor
235 trickflow heads milled
ross pistons -20cc
eagle h beam rods
beck sheetmetal intake
95 mm tb
large hydraulic roller cam

all through a turbo350/4500 vig stall/9inch with 373's

Any ideas? I figured I would be around 500rwhp...

Maybe compression is to low?
Or stall eating up alot of hp?
str8rpn is offline   Reply With Quote
Old 11-11-2011, 08:04 PM   #2
12 Second Club
iTrader: (12)
 
zracer323's Avatar
 
Join Date: Oct 2007
Location: Dayton, Ohio
Posts: 1,337
Default

What is your compression? How good is the tune? Does it feel strong?
Lots of questions to ask. I try not to get too caught up in dyno numbers as they can vary drastically from fron dyno to dyno. As long as you are sure there are not issues with it, take it to the track and see how it performs.
zracer323 is offline   Reply With Quote
Old 11-11-2011, 08:39 PM   #3
TECH Senior Member
iTrader: (4)
 
ULTIMATEORANGESS's Avatar
 
Join Date: Mar 2003
Location: eatontown,nj
Posts: 10,977
Default

you do have a big stall through a th350 and 9 inch.

though my ls2 h/c/i stalled a4 is making similar power on a mustang dyno so i dont know.


whats your tuners advice?
ULTIMATEORANGESS is offline   Reply With Quote
Old 11-12-2011, 09:59 AM   #4
On The Tree
Thread Starter
iTrader: (15)
 
Join Date: Mar 2006
Posts: 148
Default

compression is 10.5:1
tune is spot on
str8rpn is offline   Reply With Quote
Old 11-12-2011, 11:16 AM   #5
On The Tree
 
Beeterolds's Avatar
 
Join Date: Jul 2011
Location: Akron Ohio
Posts: 126
Default

Quote:
Originally Posted by str8rpn View Post
compression is 10.5:1
tune is spot on
Just for giggles and this applies to any engine thats missing power, do a compression test..

When you say large cam, how large are we talking? between 230 and 240 duration? higher? how does it drive? is it strong?

theres a bunch of variables, if your tune is spot on then the problem could be valve timing, which in turn cause many other problems, including providing you with inaccurate compression figures..

check your compression.. and go from there...
Beeterolds is offline   Reply With Quote
Old 11-12-2011, 05:06 PM   #6
On The Tree
Thread Starter
iTrader: (15)
 
Join Date: Mar 2006
Posts: 148
Default

cam is a 250/258
str8rpn is offline   Reply With Quote
Old 11-12-2011, 05:18 PM   #7
10 Second Club
iTrader: (30)
 
djfury05's Avatar
 
Join Date: Jan 2008
Location: Beaufort, SC
Posts: 3,434
Default

bore/stroke size??
djfury05 is offline   Reply With Quote
Old 11-12-2011, 11:30 PM   #8
On The Tree
Thread Starter
iTrader: (15)
 
Join Date: Mar 2006
Posts: 148
Default

4.130/4 inch stroke
str8rpn is offline   Reply With Quote
Old 11-12-2011, 11:41 PM   #9
10 Second Club
iTrader: (9)
 
82cetuner's Avatar
 
Join Date: Sep 2009
Location: Denham Springs, LA
Posts: 1,285
Default

well mustangs are known to read incredibly low, so lets say on a regular dyno you would of had about 480, still seems a little know,

was your converter locked? if not that could take away 50 hp or better
82cetuner is offline   Reply With Quote
Old 11-13-2011, 12:09 AM   #10
10 Second Club
iTrader: (20)
 
Mean87SS's Avatar
 
Join Date: Sep 2005
Location: Edison, NJ
Posts: 1,403
Default

Car running out of fuel? Low on timing?
Mean87SS is offline   Reply With Quote
Old 11-14-2011, 09:52 PM   #11
TECH Fanatic
iTrader: (3)
 
Join Date: Mar 2003
Location: Hamilton Ontario
Posts: 1,145
Default

Would think it would be higher with that much cam, really you need to take it down the quarter and see what it does.
Orange Juice is offline   Reply With Quote
Old 11-15-2011, 10:25 PM   #12
10 Second Club
iTrader: (27)
 
RsSean's Avatar
 
Join Date: Feb 2008
Location: Pensacola, FL
Posts: 2,183
Default

-20cc dish really killed power potential, plus auto, plus 9". Put some boost thur it
RsSean is offline   Reply With Quote
Old 11-15-2011, 10:33 PM   #13
TECH Veteran
iTrader: (9)
 
King Nothing's Avatar
 
Join Date: Oct 2005
Location: Central Valley
Posts: 4,116
Default

Quote:
Originally Posted by RsSean View Post
-20cc dish really killed power potential, plus auto, plus 9". Put some boost thur it
So I wasn't the only one readin -20cc and thinking wtf if you have no blower. Why would you choose those pistons if your not going to run a blower? Unless your planning on a blower
King Nothing is offline   Reply With Quote
Old 11-15-2011, 10:58 PM   #14
TECH Enthusiast
iTrader: (21)
 
Join Date: Mar 2009
Location: Sacramento Ca
Posts: 619
Default

Even with low compression he should be making more power then that. Stock cube LS1's make that even with stall and TH tranny. Somethings definitely wrong...just my 2 cents.
yonerhottlt1 is offline   Reply With Quote
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
427 stroked questions 69greyghost New LS1 Owners - Newbie Tech 5 04-05-2015 03:06 PM
RHS 427 Block limits FI O.N. Forced Induction 7 08-03-2014 02:27 PM
RHS 427 Block limits O.N. General LSX Automobile Discussion 1 08-02-2014 04:33 PM
427 LS2 vs 427 ls7 600 hp goal NA BAD-LSX-7 Generation IV External Engine 31 01-23-2011 08:52 PM
power difference between 402ci & 427ci w/same heads and cam? mike c. Generation IV Internal Engine 48 08-25-2006 10:24 PM


Tags
134, 427, 427w, aes, build, chevy, compression, dyno, dynometer, headers, hp, low, ls, motor, mustang

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are Off



All times are GMT -5. The time now is 05:26 PM.