78 mm fast - mamo ported
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Joined: Mar 2005
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78 mm fast - mamo ported
How much is a 78 mm fast mamo ported manifold worth? I am thinking about selling mine and upgrading to 90 mm as I am going to put a much larger cam in. It has been on the car for about 4000 miles.
Former Vendor
Joined: Mar 2004
Posts: 1,518
Likes: 7
From: Valencia CA
Your ported 78mm FAST will make 5 HP more than an out of the box 90mm....unless you port the 90 as well you will be going backwards. You will only see a 5 RWHP bump in power with the 90mm ported but your throttle response will improve dramatically.
When the smoke clears on the dyno however, the difference between one of my ported 78 units and ported 90's isn't very much. There is probably a better way to allocate those funds IMO....your going to spend alot of money for 5 ponies or so (ported 90 mm intake plus ported LS2 90mm TB, etc.).
My original 346 build made 475 RWHP with the ported 78 FAST....480 with the addition of the larger 90mm unit.
If your starting from scratch I feel the 90 is a good move....but already invested in a ported 78 its probably not unless you simply have to have every last pony and are willing to pay for it (or have a buyer giving you a decent buck for your original set-up).
Keep the 78 set-up, get a larger cam, add some compression, fly cut your pistons, and run a set of Yella Terra ultralite rockers....that will certainly wake up your combo.
If you need some advise you know where to find me...
Tony
Le Mans Master
Joined: Dec 2005
Posts: 8,475
Likes: 332
From: Port Arthur, Texas 77642
Russ...
Your ported 78mm FAST will make 5 HP more than an out of the box 90mm....unless you port the 90 as well you will be going backwards. You will only see a 5 RWHP bump in power with the 90mm ported but your throttle response will improve dramatically.
When the smoke clears on the dyno however, the difference between one of my ported 78 units and ported 90's isn't very much. There is probably a better way to allocate those funds IMO....your going to spend alot of money for 5 ponies or so (ported 90 mm intake plus ported LS2 90mm TB, etc.).
My original 346 build made 475 RWHP with the ported 78 FAST....480 with the addition of the larger 90mm unit.
If your starting from scratch I feel the 90 is a good move....but already invested in a ported 78 its probably not unless you simply have to have every last pony and are willing to pay for it (or have a buyer giving you a decent buck for your original set-up).
Keep the 78 set-up, get a larger cam, add some compression, fly cut your pistons, and run a set of Yella Terra ultralite rockers....that will certainly wake up your combo.
If you need some advise you know where to find me...
Tony
Your ported 78mm FAST will make 5 HP more than an out of the box 90mm....unless you port the 90 as well you will be going backwards. You will only see a 5 RWHP bump in power with the 90mm ported but your throttle response will improve dramatically.
When the smoke clears on the dyno however, the difference between one of my ported 78 units and ported 90's isn't very much. There is probably a better way to allocate those funds IMO....your going to spend alot of money for 5 ponies or so (ported 90 mm intake plus ported LS2 90mm TB, etc.).
My original 346 build made 475 RWHP with the ported 78 FAST....480 with the addition of the larger 90mm unit.
If your starting from scratch I feel the 90 is a good move....but already invested in a ported 78 its probably not unless you simply have to have every last pony and are willing to pay for it (or have a buyer giving you a decent buck for your original set-up).
Keep the 78 set-up, get a larger cam, add some compression, fly cut your pistons, and run a set of Yella Terra ultralite rockers....that will certainly wake up your combo.
If you need some advise you know where to find me...
Tony
I just put my brain on pause and ask Tony, works every time 
Former Vendor
Joined: Mar 2004
Posts: 1,518
Likes: 7
From: Valencia CA
Race Director
Joined: Jan 2006
Posts: 10,554
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From: Not on either liberal coast.
Isn't FAST introducing a 92mm LSx manifold soon? That should flood the used parts market with 78mm and 90mm manifolds.
Also, I asked in another post and didn't get an answer...when you port a composite manifold, do you use the same burrs, etc that one would use in a metal manifold?
(verano29 is curious, also)
Also, I asked in another post and didn't get an answer...when you port a composite manifold, do you use the same burrs, etc that one would use in a metal manifold?
(verano29 is curious, also)
Last edited by hotwheels57; Jan 9, 2008 at 03:17 PM.
Former Vendor
Joined: Mar 2004
Posts: 1,518
Likes: 7
From: Valencia CA
Isn't FAST introducing a 92mm LSx manifold soon? That should flood the used parts market with 78mm and 90mm manifolds.
Also, I asked in another post and didn't get an answer...when you port a composite manifold, do you use the same burrs, etc that one would use in a metal manifold?
(verano29 is curious, also)
Also, I asked in another post and didn't get an answer...when you port a composite manifold, do you use the same burrs, etc that one would use in a metal manifold?
(verano29 is curious, also)
Regarding the porting tools I use some of the same tools I use for porting aluminum. Its very easy to put a divet in the plastic intake and slow calculating material removal is the order of the day.
Tony
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St. Jude Donor '03
Former Vendor
Joined: Mar 2004
Posts: 1,518
Likes: 7
From: Valencia CA
A 78mm to a 90mm jump increases surface area by 33% (which is very significant but more significant is the fact that assuming the rest if the intake path was optimized, the 78mm TB represented a restriction in the air path and going bigger would then potentially net you some gains).
A 92 mm opening is only a 4% increase (over the 90 set-up)....BUT, other restrictions along the way have already made that a mute point anyway.
Regards,
Tony
Last edited by Tony Mamo @ AFR; Jan 9, 2008 at 08:36 PM.
