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MAF lbs/min vs RPM

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Old 01-11-2004, 01:06 AM
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Default MAF lbs/min vs RPM

Now that I can do in-car logging I am starting to find out all kinds of interesting things....one of which being:

4800rpm - 35.9 lbs/min
5000rpm - 36.6 lbs/min
5200rpm - 37.2 lbs/min
5400rpm - 36.2 lbs/min
5500rpm - 35.9 lbs/min

Definitely tells you where VE is at it's peak and where the stock cam starts to hinder performance huh, I always thought that it didn't pull as hard after 5200rpm......now I have proof

BTW...is 37.2 lbs/min good or bad on stock heads/cam ???

EDIT: assuming the 11.5 x lbs/min multiplier that was given in another post is correct that gives me 427hp flywheel horsepower @ 5200prm .....is that ANYWHERE near right ?????....and is a 6.0 with just intake/exhaust/tuning capable of those kind of numbers ???....or is the multiplier WAY off ???
Old 01-11-2004, 01:34 AM
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I saw an SS dyno with a magnaflow, K$N FIPK tube, and LS1 Edit tuning. It made 333 hp I think. You should be with 10-15 HP of that.
Old 01-11-2004, 02:12 AM
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If that was rwhp the numbers work out about right.......figure in about 23% loss for the driveline and that SS made about 430hp, jebus...are the 6.0's really THAT strong ???
Old 01-11-2004, 02:23 AM
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Originally Posted by Yelo
If that was rwhp the numbers work out about right.......figure in about 23% loss for the driveline and that SS made about 430hp, jebus...are the 6.0's really THAT strong ???
Well, consider that the 5.7L's are putting down 300+rwhp on average. That means somewhere in the neighborhood of 350-360flywheel hp(maybe more). Now add in better heads, more cubes and what do you get...MORE POWER.

I really don't know how accurate that multiplier is. I found it a long time ago somewhere on this site. It seems to work though.

Somebody needs to dyno on one of those dynos that can measure parasitic driveline losses on the coast down.

When you think about it all it takes with an old SBC to make 1hp/ci is around 9:1cr with a decent set of heads and a nice cam. The LS1 based motors are over that cr, have very good heads, and decent cams compared to most SBC cams. 1hp+/ci doesn't seem to unbelieveable to me.

Some of the numbers still seem crazy though.
Old 01-11-2004, 02:32 AM
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Originally Posted by XLR8NSS
Some of the numbers still seem crazy though.
No Doubt.....but as you say...it DOES seem reasonable to assume that a 364cid motor with great heads should be capable of outpowering a 346cid motor with "just OK" heads....especially given that they share the same cam.....

We REALLY nead to see more 6.0 baseline numbers....it makes me wonder whether the 300hp/320hp/325hp/345hp ratings are nothing more than another GM game like the one played in the late 60's/early 70's....and whether ALL of those are LESS than the actual output of the engine

AND....even figuring a 10:1 multiplier (the "turbo" multiplier) I would STILL be seeing 372fwhp......thats 72 horsepower more than it's supposedly rated stock !!!!...and the MAF reading WASN'T a fluke....I see those numbers VERY consistently
Old 01-11-2004, 02:42 AM
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Yes, BigTex needs to hurry up and get that beast of his on a dyno.

I think Jim dynoed like 285rwhp in his truck with 6.0L and 4L80E. That was in second gear also.

The highest MAF numbers I ever saw in my car N/A were in the low 30's. These 6.0L's are throwing up 34-35lb/min numbers stock so they're definately making more power.
Old 01-11-2004, 02:47 AM
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My stock dyno pull done last January was 291hp@5200rpm and 323ft/lbs@4800rpm .......I have NEVER believed it was accurate, I just assumed it was operator error or a dyno glitch, now that I see this info I am actually starting to believe those numbers
Old 01-11-2004, 11:46 PM
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Just for grins I made a few logs in my truck this evening. I am seeing consistant 37-38 lb/min above 5k with a max value of 39.04 @ 5966 rpm. That is 460HP by the above calculation! I know that isnt right.. this is on my 5.3 with GenII, 2K Vette cam, Hamm Headers, dual 2.5" Magnaflows w/xpipe...
Old 01-12-2004, 01:48 PM
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supposedly I am making 644hp with that multiplier LOL
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