ported 90/90
Pro
Joined: Feb 2003
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From: Ankeny IA
That is great info Tony and I really appreciate the response. That's certainly enlightening on the 78mm version. However I'm still fuzzy on how a step up to a 90mm TB and intake would give any sort of a gain with the 75mm MAF in place. You should be utilizing it's maximum airflow in a 78mm setup and stepping up to a 90mm setup wouldn't allow anymore air into the system. It would be stuck at the maximum flow of the MAF.
Former Vendor
Joined: Mar 2004
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From: Valencia CA
That is great info Tony and I really appreciate the response. That's certainly enlightening on the 78mm version. However I'm still fuzzy on how a step up to a 90mm TB and intake would give any sort of a gain with the 75mm MAF in place. You should be utilizing it's maximum airflow in a 78mm setup and stepping up to a 90mm setup wouldn't allow anymore air into the system. It would be stuck at the maximum flow of the MAF.
Keep in mind you are only actually seeing a small percentage increase in power (1%) in spite of a 40-50% increase in total available airflow (on paper looking at max CFM at the TB) moving from a 75mm TB to a 90mm TB.
And the larger 85mm MAF is only worth a few more ponies (about 3HP) over its smaller 75mm brother. In fact you can eliminate the MAF completely and see a total of 5 HP over the same engine with an 85mm MAF installed as a baseline (at the 600 HP level at the crank....less on a lower output engine). That would indicate the total power loss associated with a 75 mm MAF even at the 600 HP mark is only around 8-10 HP.
Tony
Last edited by Tony Mamo @ AFR; Sep 4, 2008 at 05:49 PM.
Pro
Joined: Feb 2003
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From: Ankeny IA
While we're on the subject, any use in a MAF larger than 85mm on an NA 346? My gut says that any gain would be very minimal and not worth the investment. Now on a 400+ cube stroker I would guess very large MAF's should be well worth the time and money.
Former Vendor
Joined: Mar 2004
Posts: 1,518
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From: Valencia CA
That's the piece I was missing. Makes sense now. Well if you're gaining 5hp moving to the 90, I guess the extra 3hp or so from the MAF can't hurt.
While we're on the subject, any use in a MAF larger than 85mm on an NA 346? My gut says that any gain would be very minimal and not worth the investment. Now on a 400+ cube stroker I would guess very large MAF's should be well worth the time and money.
While we're on the subject, any use in a MAF larger than 85mm on an NA 346? My gut says that any gain would be very minimal and not worth the investment. Now on a 400+ cube stroker I would guess very large MAF's should be well worth the time and money.
BUT...for the price, assuming you were dropping dime on a 92/90 set-up (and especially a ported one looking for all the money), the swap to an 85mm MAF at the same time would certainly help your cause (but require a new tune to compensate for it).
Tony
Pro
Joined: Mar 2007
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From: Ashland Kentucky
Exactly. The OP says "Ported", but then just shows port matching. BIG difference. Porting the intake is done inside... the ports are just a detail compared to the inner porting. Port matching is a simple job. Porting the interior is where the mastery is needed.
So is this supposed to be "ported"? Or just "port matched"?
So is this supposed to be "ported"? Or just "port matched"?
Team Owner
Joined: Mar 1999
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From: At the beach in little Rhody
Tony posted some photo's several months back that he had sent me when he did my intake. All I can tell you is that the porting work is head and shoulders better than that shown in the first post of this thread. I plan to take advantage of that work next month when my Dart heads come off and the AFR heads go on, that also have some of Tony's handiwork.
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Drifting
Joined: Nov 2004
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From: Ringgold GA
Former Vendor
Joined: Mar 2004
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From: Valencia CA
I usually recommend to my customers wanting to swap to the larger MAF to simply bring it with them to the shop when its time for the tune (and previous to that making sure you have the right complimenting parts to install it by taking the time to sort all that out prior to going there).
Tony
Drifting
Joined: Nov 2004
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From: Ringgold GA
Thanks, i'm not gonna swap my stock ls6 MAF, I think it's what 85mm anyway? And I'm going to run my stock LS2 throttle body, although I might polish it if there's any benefit to that, but no material removal. I can't see the need to port a 90mm throttle body for an n/a 346 car with mild heads and cam, do you?
Tech Contributor
Joined: Sep 2005
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From: New Market AL
Former Vendor
Joined: Mar 2004
Posts: 1,518
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From: Valencia CA
I also have the luxury of seeing alot of my competitors CNC product so that is very helpful as well concerning port size and location (most are actually very similar). The only real issues is porting intakes for hand ported heads (or stock heads) when there can be a big disparity in port width, height etc. and in the event I am porting an intake for someone in that situation I usually have them provide me with measurements so I have a better idea of how aggressive to get on the port exit of the FAST. The reality is most of the gains that actually help airflow are up the port aways and the actual exit size doesn't have to big a role on airflow assuming it's at least close....
Tony
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Joined: Mar 2007
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From: Ashland Kentucky
Once again, it becomes brutally apparent that some people lack understanding that "porting" an intake is internal in the runners, and "port matching" is the ends of the runners matching the heads. This thread is about "ported" intakes. Not "port matched". My dog could port match an intake. But doing the porting (in the runners) is much tougher.