Truth about the MAFless tune.

[conp]

Pir4te you sound rather knowledgeable but we are inside a VY thread discussing LS1's, mafless vs maf, and obviously CAI is relevant to the discussion not a pissing contest as you put it. Your L92 info is wonderful and I can see you must also be a member of LS1 tech as you showcase PAT G on your graph, but I would like to know flow limitations on LS1, mafs and CAI's as I would like to fit a small cam and I'm most interested to know the cfm flows revolving around that. Any advice that you wish to share...?

 

[ConstantVelocity]

Pir4te, what's your source for all LS1 otrs flowing 1400 cfm? Maybe at 5 psi pressure drop lol... cfm ratings are meaningless without specifying pressure drop. A 250 cfm @ 28" water intake would strangle the crap out of an LS1. They suck in ~400 cfm at peak power. Even a 400 cfm @ 28" intake tract would strangle it because you'd lose 28" water (~1psi).

 

[PIR4TE]

Pir4te, what's your source for all LS1 otrs flowing 1400 cfm? Maybe at 5 psi pressure drop lol... cfm ratings are meaningless without specifying pressure drop. A 250 cfm @ 28" water intake would strangle the crap out of an LS1. They suck in ~400 cfm at peak power. Even a 400 cfm @ 28" intake tract would strangle it because you'd lose 28" water (~1psi).

Mate we are talking at cross purposes - flow at head (per bank) versus engine flow. Agreed, induction on a stock LS1 needs much less than 450 CFM at 1 psi, max lift, agreed (all above figures are 28" h2o).
My point is the ridiculous focus on pre-TB flow which is at least 2x overkill, sold on the premise that the proof of benefit is a dyno chart showing hp with IAT corrected to J607 (15.5°C). The reality is that these OTRs are tested at 18-25°C but run at least 2x as hot as the ideal shown on the dyno, up to 5x in my experience.
Where do I source the 1400 CFM OTR claim? Well, they all do indirectly by assuming one manufacturer's research claim then proving their slightly modified trumpet makes denser air, by way of print out using a corrected dyno. This is typical http://www.pfyc.com/G83013.html
My point is that replacing the MAF is with a better unit in a less restrictive housing is a good move, while time spent deliberating which brand of plastic trumpet sitting on top of your radiator will give the best hp gain as shown on the marketer's dyno is a furphy.
All 'independent' tests I've seen are not real world rather clinical, as 95% of the time you get IAT 40°-70°C and like ConstantVelocity mentioned this can make your MAFless tune wander like a drunk in the sun.
I follow G8 guys in Nevada / Arizona and the Carolinas who get some of the best real world results by keeping the MAF / temp sensor away from heat directly behind the radiator at the top of the engine bay.

 

[Kiddo]

Mate we are talking at cross purposes - flow at head (per bank) versus engine flow. Agreed, induction on a stock LS1 needs much less than 450 CFM at 1 psi, max lift, agreed (all above figures are 28" h2o).
My point is the ridiculous focus on pre-TB flow which is at least 2x overkill, sold on the premise that the proof of benefit is a dyno chart showing hp with IAT corrected to J607 (15.5°C). The reality is that these OTRs are tested at 18-25°C but run at least 2x as hot as the ideal shown on the dyno, up to 5x in my experience.
Where do I source the 1400 CFM OTR claim? Well, they all do indirectly by assuming one manufacturer's research claim then proving their slightly modified trumpet makes denser air, by way of print out using a corrected dyno. This is typical Vararam VR-G8 Ram Air Intake System - 08-09 G8 GT GXP - PFYC.com
My point is that replacing the MAF is with a better unit in a less restrictive housing is a good move, while time spent deliberating which brand of plastic trumpet sitting on top of your radiator will give the best hp gain as shown on the marketer's dyno is a furphy.
All 'independent' tests I've seen are not real world rather clinical, as 95% of the time you get IAT 40°-70°C and like ConstantVelocity mentioned this can make your MAFless tune wander like a drunk in the sun.
I follow G8 guys in Nevada / Arizona and the Carolinas who get some of the best real world results by keeping the MAF / temp sensor away from heat directly behind the radiator at the top of the engine bay.

Nothing wake me up in the morning quite like a P1R4TE rant

 

[PIR4TE]

Splice the mainbrace! Me rants t' sleep 'n wake up in dribble!

Walk the gangplank!