LS2 427n/a #'s not what I thought
08-25-2011, 05:11 PM
#41
Why in the hell would the "tuner" recommend an LS7 cam for LS1 heads? No offense but if that's what he told you, he doesn't know his *** from his elbow.
What you have is a big pump - 427ci - trying to breath through a tiny hole - LS1 heads. On the back end, it's trying to push whatever air it manages to wheeze in through a small hole.
FWIW: My 427 with cnc'd L92 heads makes 577/530 at the wheels with a cam a total of 16 degrees smaller than what's in your motor now.
You really need to put a plan together to optimized the cubes or live with what you have.
Just my $.02
What you have is a big pump - 427ci - trying to breath through a tiny hole - LS1 heads. On the back end, it's trying to push whatever air it manages to wheeze in through a small hole.
FWIW: My 427 with cnc'd L92 heads makes 577/530 at the wheels with a cam a total of 16 degrees smaller than what's in your motor now.
You really need to put a plan together to optimized the cubes or live with what you have.
Just my $.02
Last edited by WKMCD; 08-25-2011 at 06:45 PM.
08-25-2011, 05:36 PM
#42
here is what I have. resleved ls2 ported/polished ls1 heads 244/244 612/612 mti s1 cam 90/90fast 1 3/4 headers 3" y pipe gmmg exhaust. numbers came back at 455/460. was thinking and wanting over 500. all thru a m6 car peaked quick at 5800-5900. Guy that did the tuning and dyno said it makes it power quick.
with that said I know there are better heads and maybe even a diff cam that would get me there. I just dont know where to start. any info would be apperciated
with that said I know there are better heads and maybe even a diff cam that would get me there. I just dont know where to start. any info would be apperciated
Something else besides breathing is going on............but yes.....our heads and intakes pretty much suck.....well, they don't suck...
.
08-25-2011, 09:52 PM
#44
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More info A little more info on the heads. Ferrea stainless steal 2.080" intake and 1.60" exhaust. custom double valve springs, titanium retainers, custom spring locators. good, bad ok.?
08-26-2011, 12:29 AM
#46
You mean my heads????......basic hand ported LS1's. They suck.
You and me both have AT LEAST 100 RWHP on the table. 150 even......
I'm not bothering with this top end since I have a new 441ci coming soon. I'm gonna either put ported LS7 heads and ported LS7 intake on it with LS7 TB. Or same heads with MAMO ported FAST 102/102. Cam too match of course.
Thats what your 427ci needs if you want to get closer to its max potential.
It will make another 100+ RWHP right there.
.
08-26-2011, 01:27 AM
#48
08-26-2011, 05:09 AM
#49
MTI used to get 500/500 from their sleeved 427s 6-7 years ago with just ported 241 heads, LS6 intakes and through the cats. While there are much better options today such as the offerings from TFS/AFR/TSP or GMs L92/LS3/LS7 stuff, your engine is definately missing 45-55ish somewhere with just the parts you have.
The engine should be checked for compression and the cam should be checked for correct installation and accuracy of the grind.
The engine should be checked for compression and the cam should be checked for correct installation and accuracy of the grind.
08-26-2011, 08:34 AM
#50
First and foremost, the dyno is just a tuning tool- we don't race dynos. Anybody ever consider the dyno might be very conservative? Maybe it the air was bad on the day he ran the dyno test? The combination is not optimized, I am not disputing that, but to suggest he is running on less than 8 cylinders or that his engine isn't making compression is really shooting in the dark. Take the car out and make some passes at the track. If it isn't set up to be a "good" drag car, just look at the mph versus your race weight and that will give you a fairly good indication of how the engine is running in terms of power.
Fwiw, the heads on the engine in my signature probably aren't any bigger than his ported LS1 heads at 225cc. My cam was also smaller and while I never dyno'd the combo, my times indicate something on the order of 530rwhp. My immediate suggestions would be to ditch the FAST intake and change the exhaust system, despite the dyno results.
Fwiw, the heads on the engine in my signature probably aren't any bigger than his ported LS1 heads at 225cc. My cam was also smaller and while I never dyno'd the combo, my times indicate something on the order of 530rwhp. My immediate suggestions would be to ditch the FAST intake and change the exhaust system, despite the dyno results.
08-26-2011, 11:01 AM
#51
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This is what I was trying to say buddy. Get a custom cam cut to your specs and you will make power. The person specing the cam will know what questions to ask.. I build motors not cams!!
08-26-2011, 11:56 AM
#52
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You mean my heads????......basic hand ported LS1's. They suck.
You and me both have AT LEAST 100 RWHP on the table. 150 even......
I'm not bothering with this top end since I have a new 441ci coming soon. I'm gonna either put ported LS7 heads and ported LS7 intake on it with LS7 TB. Or same heads with MAMO ported FAST 102/102. Cam too match of course.
Thats what your 427ci needs if you want to get closer to its max potential.
It will make another 100+ RWHP right there.
.
You and me both have AT LEAST 100 RWHP on the table. 150 even......
I'm not bothering with this top end since I have a new 441ci coming soon. I'm gonna either put ported LS7 heads and ported LS7 intake on it with LS7 TB. Or same heads with MAMO ported FAST 102/102. Cam too match of course.
Thats what your 427ci needs if you want to get closer to its max potential.
It will make another 100+ RWHP right there.
.
08-26-2011, 08:51 PM
#53
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alright well with all the info gathered from everyone who has gave there .02(thank you) what info will I need to know to make the right choice on a set of heads and what will a cam builder need to know about the motor & new choice of heads to help me get to were I want to be.?
08-26-2011, 09:39 PM
#54
alright well with all the info gathered from everyone who has gave there .02(thank you) what info will I need to know to make the right choice on a set of heads and what will a cam builder need to know about the motor & new choice of heads to help me get to were I want to be.?
.
08-27-2011, 03:55 PM
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1. You need to figure out what you want to do with the car. Street...Strip...both?
2. How do you want to get there? NA, FI, NO2
3. If you are getting new heads...talk to someone about what you want many sponsors here could help...
4. Many of the sponsors can help with cam selection also...they will ask you questions about your set-up and what you want and derive specs from there. They will ask about your transmission (A4, M6), rear gears, SCR, DCR, piston dish/flat etc, head chamber cc...etc. If you are building yourself piston to valve clearance should be checked when putting it together. Just some of my thoughts.
2. How do you want to get there? NA, FI, NO2
3. If you are getting new heads...talk to someone about what you want many sponsors here could help...
4. Many of the sponsors can help with cam selection also...they will ask you questions about your set-up and what you want and derive specs from there. They will ask about your transmission (A4, M6), rear gears, SCR, DCR, piston dish/flat etc, head chamber cc...etc. If you are building yourself piston to valve clearance should be checked when putting it together. Just some of my thoughts.
