PLEASE HELP on LQ9 427ci
Thread Starter
Instructor
Joined: Mar 2011
Posts: 190
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From: Denver CO
PLEASE HELP on LQ9 427ci
Hey Guys I am wondering what is the MAX RPM I can make with LQ9 427ci? Also, I have CAM "227 intake duration at .050 .620 lift 220 exhaust duration at .050 .612 lift 114 lobe separation angle" I would like somebody to help me with it by knowing when it is gonna start puling and what it is max too as of RPM wise. This is my mods :
P.S I am porting my LS2 heads and changing it Valves.
Thank you
P.S I am porting my LS2 heads and changing it Valves.
Thank you
_Sloth Whisperer_
Joined: Jul 2008
Posts: 3,369
Likes: 9
From: Malaysia Air Flight 370
That depends heavily on your valvetrain, which you haven't given much insight into. The cam you're running is rather mild, but whatever the lobe profiles are will dictate ramp rates which generally impart the majority of stress (or lack thereof) on the springs. Which springs are you using? What hardware? What valves? What rockers? Shaft mount or OEM style? What brand?
Depending on what level of risk you are comfortable with, and how precisely the engine is assembled/machined, you could spin it to likely 7500rpm, and possibly more. All out, all motor drag LSX's are sometimes spun all the way beyond 9 grand. They're built to handle it though, and only long enough for a season if that.
Depending on what level of risk you are comfortable with, and how precisely the engine is assembled/machined, you could spin it to likely 7500rpm, and possibly more. All out, all motor drag LSX's are sometimes spun all the way beyond 9 grand. They're built to handle it though, and only long enough for a season if that.
Thread Starter
Instructor
Joined: Mar 2011
Posts: 190
Likes: 0
From: Denver CO
That depends heavily on your valvetrain, which you haven't given much insight into. The cam you're running is rather mild, but whatever the lobe profiles are will dictate ramp rates which generally impart the majority of stress (or lack thereof) on the springs. Which springs are you using? What hardware? What valves? What rockers? Shaft mount or OEM style? What brand?
Depending on what level of risk you are comfortable with, and how precisely the engine is assembled/machined, you could spin it to likely 7500rpm, and possibly more. All out, all motor drag LSX's are sometimes spun all the way beyond 9 grand. They're built to handle it though, and only long enough for a season if that.
Depending on what level of risk you are comfortable with, and how precisely the engine is assembled/machined, you could spin it to likely 7500rpm, and possibly more. All out, all motor drag LSX's are sometimes spun all the way beyond 9 grand. They're built to handle it though, and only long enough for a season if that.
!!!!!!Personally I would love to have my RPM from 7000-7500 and if it is gonna go higher I dont mind if there is no Risk to the engine. Also I am sorry that I didn't provide more info because I am not an expert
"I am still learning" and this is my first build 
in my life. So tomorrow I will call the shop that is building my block to answer all the questions and let me know please if there is more questions that I have to ask him
_Sloth Whisperer_
Joined: Jul 2008
Posts: 3,369
Likes: 9
From: Malaysia Air Flight 370
If they're a good shop and they value your business, they will take the 5 or 10 minutes to have a tech or tuner actually teach you a little about your engine while you're standing next to it. Just having them rattle off a parts list that means little to you other than in terms of money spent isn't really helping you.
A good tuner/builder, even a busy one, will acknowledge that you're spending thousands of dollars in a shot, and should be happy to explain a little to you about how each part transmits energy to the next, and why each does what it does. If or when somebody is purchasing something from me, no matter how small, I want them to know truly what it is they're dropping their hard earned money on, and not just its shelf name.
When you get a more comprehensive list, ask your builder to give you a bit of a rundown. Even if he's a busy man, he should find time to oblige.
A good tuner/builder, even a busy one, will acknowledge that you're spending thousands of dollars in a shot, and should be happy to explain a little to you about how each part transmits energy to the next, and why each does what it does. If or when somebody is purchasing something from me, no matter how small, I want them to know truly what it is they're dropping their hard earned money on, and not just its shelf name.
When you get a more comprehensive list, ask your builder to give you a bit of a rundown. Even if he's a busy man, he should find time to oblige.
Thread Starter
Instructor
Joined: Mar 2011
Posts: 190
Likes: 0
From: Denver CO
If they're a good shop and they value your business, they will take the 5 or 10 minutes to have a tech or tuner actually teach you a little about your engine while you're standing next to it. Just having them rattle off a parts list that means little to you other than in terms of money spent isn't really helping you.
A good tuner/builder, even a busy one, will acknowledge that you're spending thousands of dollars in a shot, and should be happy to explain a little to you about how each part transmits energy to the next, and why each does what it does. If or when somebody is purchasing something from me, no matter how small, I want them to know truly what it is they're dropping their hard earned money on, and not just its shelf name.
When you get a more comprehensive list, ask your builder to give you a bit of a rundown. Even if he's a busy man, he should find time to oblige.
A good tuner/builder, even a busy one, will acknowledge that you're spending thousands of dollars in a shot, and should be happy to explain a little to you about how each part transmits energy to the next, and why each does what it does. If or when somebody is purchasing something from me, no matter how small, I want them to know truly what it is they're dropping their hard earned money on, and not just its shelf name.
When you get a more comprehensive list, ask your builder to give you a bit of a rundown. Even if he's a busy man, he should find time to oblige.
All what you have said is Damm right and true. Since you replied last time to me, I felt I got ripped off
!!! then I called the shop and I left a message for the builder and he didn't get back to me then everytime I call his shop they tell me he is busy so after 4 days he got back to me and I understood his circumstances. So I asked him about my Cam and he said it should me good to 7000 RPM same as my engine too. He told me I don't recommend you going over 7000 RPM for the engine. Also My heads will be flowing 330 to the intake and 240-245 to the exhaust with 9:1 CR. I will meet up with him this week to get more info instead of calling him in the phone and to tell me about the rundown.
Thread Starter
Instructor
Joined: Mar 2011
Posts: 190
Likes: 0
From: Denver CO
which is twin turbo. I wouldn't go that low CR without force inductions
Last edited by ABVETTE86; Mar 17, 2012 at 06:16 PM.
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