When I was cleaning the TB today, I went ahead and measured it, and it actually has 4"of total intake (combining both) That is ~ 105mm. The MAF is only 3" 80mm. I wonder is going to a L 90mm MAF will result in any better performance. I would have to get my chip reburned, but I though that was weird. The new trucks have an 80mm MAF, but the TB is "really" 68mm. I wonder why they gave us such a big TB.

 

Boy you are always up to something. I swear you'd go crazy if you couldnt touch that truck for a week.

On a side note:
I have no clue.

 

When I get bored, I go and just stare into the engine bay, or just look under the truck LOL At least I am interested in Amrican power, and dont drive Rice Rockets like everyone else my age

 

LOL I get the same way when I'm bored(which is a lot) I sit there and stare trying to get an excuse to do something...Chris(PKRWUD) suggest I need to get a wife and kids..maybe you too LOL

 

*Spaceman shakes Beastie's hand.

Nobody here likes a four door bumble bee.

Dang I hope my bike doesn't count.

 

they are classified as a dual bore 50mm throttle body. This is the same throttle body used on the 351. However, the 4.9 uses a dual bore 40mm. This is not actually all that large considering the mustang 302's that are designed for more HP only have a 60 or 65mm....so a dual bore 50 is not even close to the same as a single bore 100. And on MAF, about the only time it is worth replacing the stock unit is if the engine mods alone cause the MAF meter to max out at 5 volts. Other than that, bang for the buck is gonna kill ya.

 

Thanks for the info.

 

Actually if you do the math, our trucks have fairly large TBs. To find the area you multiply pi x radius squared. Then in this case multiply the total by the two throttle bodies.

If you take the total and divide by pi once again, and find the square root of that number, you will find that our twin 50s are equal in area to a single 70.7 mm unit.


I've often wondered why the duals are only used in certain apps regardless of total size. The smaller duals should allow more precise air flow control at lower TB openings, and in turn help maintain intake velocity at lower revs by splitting the incoming air into two TBs.


Maybe the Tornado people should make an app for our trucks with one forcing air to spin clockwise and the other TB counter clockwise. With their logic they could call it a twin screw intake.

 

LOL, I can just see some people shelling out 70 bucks for something that simply restrics air by spinning it in opposite directions.

I realize if you took the total volume of the 2 bores it would be much more, but unfortunately you can't compare the 2 together. I really couldn't tell you why as a matter of fact, but It just has to be! That is what many people have told me anyway. BBK makes those huge 60mm dual bore T-bodies for our trucks (and run over $300 ). For our trucks with dual T-bodies there really isn't any set standards for how much HP they can handle. The mustang guys have it easy, it is fairly common knowledge for some of them to know exactly what size T-body to use.

Also, think of it this way...Oversized throttle bodies (to big for amount of air being sucked in) are bad for a vehicle, so if the 2 kinds were really comparable I would say a dual 50 would definately be oversized. I would sure like to find out though. I have looked at a few truck crate engines rated at 375HP (351W) that used the dual bore 60mm from BBK so it does appear they work fine.

 

Gamehunter,

I would also tend to think a single would have more total flow per a given area due to the fact that the air from both TBs has to merge somewhere in the intake. What is interesting is that some of the highest performance vehicles around use a similar dual TB setup, but with a single throttle blade and the TBs merged as one unit. Cobras, Lightnings and LS1s all use this type setup, so there must be some reasoning behind it.

The only logic I can think of is the fact that twins meter better at small openings. I've seen flow formulas somewhere.... and they are mind numbing. By working better at small openings, they allow for better WOT flow without causing the sluggishness of too large of a TB. At least this is MY theory. LOL