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MAF size for 408

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Old Jul 9, 2011 | 02:08 PM
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331stroker's Avatar
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Default MAF size for 408

Guys,
What size MAF is needed for a stroked LQ9 408?
I keep hearing the stock LS1 MAF is too small. I believe it is 78MM.
If it is, will a Z06 85MM MAF cure the problem?

Oh yeah??? The problem is, we seem to be running out of air at WOT.

Using HP tuner to tune with.
It's either the tune, the MAF or weak valve springs. The heads were reworked about 2,000 miles ago, although we did discover we were running too long of a pushrod. Changing the pushrods helped alot.
There is no missfire at WOT Pulls to 6,000 hard then falls off.

Running a LS6 intake,ported TB, custom EPS cam 604/607 lift, shorty headers, gutted cats, Magnaflow exhaust, 243 Patriot stg 2 heads (reworked) (valves were not seating correctly out of the box), 36# FAST Injectors, 255LPH fuel pump, K&N cold air intake setup.

Any answers appreciated...
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Old Jul 9, 2011 | 02:38 PM
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Z06 MAF will help some. A FAST 90/90 or higher will help more...especially over 6K RPM.

I run a 85MM with a FAST setup on my stock shortblock. Pulls real nice up top.
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Old Jul 9, 2011 | 03:45 PM
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Im not sure what the duration is on your cam - but for perspective my 416 has a 244/250 hyd roller in it with TFS 235s.

with the pacesetter lts, fast 92/92, and Z06 85mm MAF, hp pretty much flat lined at 5,700 rpm to 6,400rpm then started going down. Was 3 cells from maxing out the MAF.
Swapped out the pacesetters for some kooks stepped lt's, didn't put it back on the dyno but data logs indicated I was still choking my engine past 5,700 rpm. Swapped a supervic/4150 tb but haven't even driven it yet. Will be going SD tune though.

In your case, I do not think going with a bigger MAF alone will provide the gain you are looking for. If you upgrade the MAF, highly consider upgrading the intake and TB as well.
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Old Jul 9, 2011 | 05:00 PM
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Thanks guys for responding...

The cam duration is 238/246.
Sounds like this fire breathing dragon needs intake, throttle body, maf and long tube headers to reach 6,800.
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Old Jul 9, 2011 | 08:14 PM
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I ran a 100mm PowerMax MAF in my 403 build and still run it in the 427.

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Old Apr 10, 2020 | 08:43 PM
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Default 408 shutting off at 5700 rpm

Originally Posted by 99TransAmLS16Spd
Im not sure what the duration is on your cam - but for perspective my 416 has a 244/250 hyd roller in it with TFS 235s.

with the pacesetter lts, fast 92/92, and Z06 85mm MAF, hp pretty much flat lined at 5,700 rpm to 6,400rpm then started going down. Was 3 cells from maxing out the MAF.
Swapped out the pacesetters for some kooks stepped lt's, didn't put it back on the dyno but data logs indicated I was still choking my engine past 5,700 rpm. Swapped a supervic/4150 tb but haven't even driven it yet. Will be going SD tune though.

In your case, I do not think going with a bigger MAF alone will provide the gain you are looking for. If you upgrade the MAF, highly consider upgrading the intake and TB as well.
did you ever figure out why your 408 was falling out at 5700? Mine is doing the same thing and I can't figurge it out for nothing..anyone pkease help?!?!
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Old Apr 11, 2020 | 12:30 AM
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Good question- Poster hasn't been here in about 8 years
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