Most NA HP & pass the sniff
Thread Starter
Staging Lane
Joined: Oct 2004
Posts: 70
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From: AUSTIN, TEXAS
Most NA HP & pass the sniff What is the most hp that can be expected from a non stroked, without funny gas, natural aspirated 5.7L LS engine?
From what I’ve seen so far is about 435 rwhp. Is this about the limit?
From what I’ve seen so far is about 435 rwhp. Is this about the limit?
Thread Starter
Staging Lane
Joined: Oct 2004
Posts: 70
Likes: 0
From: AUSTIN, TEXAS
I believe from the other posts on here that cut-off point to pass the sniff test is around 228 cam duration. So if someone is quoting 450 hp or something like that with a 235 cam its really doubtful they passed the sniff test without there being a payoff being involved. Right or Wrong?
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From: BFE
Originally Posted by Shinerbock07
its usually the LSA that people have trouble passing emissions with, i heard 112 is the max
As mentionned above -6>-7 overlap is a sure bet with good tune.
There has been as low as -4 overlap that passed but that tuner must have done a really good job.
Thread Starter
Staging Lane
Joined: Oct 2004
Posts: 70
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From: AUSTIN, TEXAS
I think the LSA plays a bigger part than duration but from what I have read here 228 is about it with 113 or 114 lsa.
One question I have: Is it the exhaust duration or the intake duration that is the main concern, or is it both equally to be concerned about? Is a split duration cam like 224/230 or a reverse split better in regards to emissions 230/224 than maybe a 228/228?
One question I have: Is it the exhaust duration or the intake duration that is the main concern, or is it both equally to be concerned about? Is a split duration cam like 224/230 or a reverse split better in regards to emissions 230/224 than maybe a 228/228?
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From: BFE
GUYS<
READ MY LIPS
IT HAS TO DO WITH OVERLAP.
OVERLAP @ .050 = (INTAKE DUR + EXHAUST DUR)/2 - 2X LSA
FOR A 228/228 TO PASS
(228+228)/2 - 2X LSA = -6
228 - 2X LSA = -6
228 + 6 = 2X LSA
(228 + 6)/2 = LSA
234/2 = LSA
117 = LSA
So your LSA on the 228/228 cam should be 117 to have any hope of passing with a GOOD trick tune.
In reality this will be a shitty cam that spins to neverland.
READ MY LIPS
IT HAS TO DO WITH OVERLAP.
OVERLAP @ .050 = (INTAKE DUR + EXHAUST DUR)/2 - 2X LSA
FOR A 228/228 TO PASS
(228+228)/2 - 2X LSA = -6
228 - 2X LSA = -6
228 + 6 = 2X LSA
(228 + 6)/2 = LSA
234/2 = LSA
117 = LSA
So your LSA on the 228/228 cam should be 117 to have any hope of passing with a GOOD trick tune.
In reality this will be a shitty cam that spins to neverland.
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Staging Lane
Joined: Oct 2004
Posts: 70
Likes: 0
From: AUSTIN, TEXAS
Originally Posted by PREDATOR-Z
GUYS<
READ MY LIPS
IT HAS TO DO WITH OVERLAP.
OVERLAP @ .050 = (INTAKE DUR + EXHAUST DUR)/2 - 2X LSA
FOR A 228/228 TO PASS
(228+228)/2 - 2X LSA = -6
228 - 2X LSA = -6
228 + 6 = 2X LSA
(228 + 6)/2 = LSA
234/2 = LSA
117 = LSA
So your LSA on the 228/228 cam should be 117 to have any hope of passing with a GOOD trick tune.
In reality this will be a shitty cam that spins to neverland.
READ MY LIPS
IT HAS TO DO WITH OVERLAP.
OVERLAP @ .050 = (INTAKE DUR + EXHAUST DUR)/2 - 2X LSA
FOR A 228/228 TO PASS
(228+228)/2 - 2X LSA = -6
228 - 2X LSA = -6
228 + 6 = 2X LSA
(228 + 6)/2 = LSA
234/2 = LSA
117 = LSA
So your LSA on the 228/228 cam should be 117 to have any hope of passing with a GOOD trick tune.
In reality this will be a shitty cam that spins to neverland.
(228+228)/2 - 2X LSA = -6
228 - 2X LSA = -6
228 + 6 = 2X LSA
(228 + 6)/2 = LSA
234/2 = LSA
117 = LSA
Equation B (Cut-off point to pass sniff)
(224+224)/2 – 2X LSA=-6
224 - 2X LSA = -6
224 + 6 = 2X LSA
(224+6)/2 = LSA
230/2 = LSA
115 = LSA
Proven fact TR224 224/224 LSA 114 passes sniff test easy with room to spare.
Equation B = false
If Equation B = false then Equation A = false
Equation C (Cut-off point to pass sniff)
(224 + 224)/2 – 2X LSA= -4
224 - 2X LSA = -4
224 + 4 = 2X LSA
(224+4)/2 = LSA
228/2 = LSA
114 = LSA = proven statement
-4 for sure maybe, –3 or even –2 for the fixed variable in these equations.
Responding to read my lips
TECH Senior Member
Joined: Mar 2004
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From: BFE
Originally Posted by M2SPEED
Equation A (Cut-off point to pass sniff test)
(228+228)/2 - 2X LSA = -6
228 - 2X LSA = -6
228 + 6 = 2X LSA
(228 + 6)/2 = LSA
234/2 = LSA
117 = LSA
Equation B (Cut-off point to pass sniff)
(224+224)/2 – 2X LSA=-6
224 - 2X LSA = -6
224 + 6 = 2X LSA
(224+6)/2 = LSA
230/2 = LSA
115 = LSA
Proven fact TR224 224/224 LSA 114 passes sniff test easy with room to spare.
Equation B = false
If Equation B = false then Equation A = false
Equation C (Cut-off point to pass sniff)
(224 + 224)/2 – 2X LSA= -4
224 - 2X LSA = -4
224 + 4 = 2X LSA
(224+4)/2 = LSA
228/2 = LSA
114 = LSA = proven statement
-4 for sure maybe, –3 or even –2 for the fixed variable in these equations.
Responding to read my lips
(228+228)/2 - 2X LSA = -6
228 - 2X LSA = -6
228 + 6 = 2X LSA
(228 + 6)/2 = LSA
234/2 = LSA
117 = LSA
Equation B (Cut-off point to pass sniff)
(224+224)/2 – 2X LSA=-6
224 - 2X LSA = -6
224 + 6 = 2X LSA
(224+6)/2 = LSA
230/2 = LSA
115 = LSA
Proven fact TR224 224/224 LSA 114 passes sniff test easy with room to spare.
Equation B = false
If Equation B = false then Equation A = false
Equation C (Cut-off point to pass sniff)
(224 + 224)/2 – 2X LSA= -4
224 - 2X LSA = -4
224 + 4 = 2X LSA
(224+4)/2 = LSA
228/2 = LSA
114 = LSA = proven statement
-4 for sure maybe, –3 or even –2 for the fixed variable in these equations.
Responding to read my lips
A 224/ 112 will fail.
I was trying to explain the way to find overlap and not "I heard this and I heard that."
There has been records of 228 passing.
And a 228 with -4 overlap has but a slim chance to pass.
At -6/-7* overlap you cannot fail if everything running like it should.
Ok, so with the VE calculator I was playing around with my numbers.
228/228 .588/.588 @112 ICL 110
The overlap is 4 degrees.
I guess the lingo is what is getting me.. as low as -4? if the -6/-7 is the cut-off wouldnt it be as high as -4? assuming +4 overlap > -4 overlap?
Thus the 228R @112 +2 wouldn't pass smog/emissions ?
228/228 .588/.588 @112 ICL 110
The overlap is 4 degrees.
I guess the lingo is what is getting me.. as low as -4? if the -6/-7 is the cut-off wouldnt it be as high as -4? assuming +4 overlap > -4 overlap?
Thus the 228R @112 +2 wouldn't pass smog/emissions ?
