For a procharger Street Strip combo

A single blade with an 90 elbow on the intake or a progressive 4 blade
http://www.fuelairspark.com/Products...ake_bm92mm.asp

http://www.injector.com/throttlebodies.php and a carb hat

I was worried about sealing of the 4 blade
http://www.thesuperchargerstore.com/...r/IMG_1806.JPG

Hello,

For the street/strip I would say the progressive 4 blade.

Damon

For a pressurized system I'd go with the single

I have yet to see anybody run anything other than a single blade throttle body an a single four barrel manifold in a blow thru application.
You could start a trend

Single blade is more common, cheaper, and easier to hook up to the outlet of your turbo/sc,but the 4 hole works very well. Pick what you like or is easiest for you.

95MM single here.I haven't had an issue with it at all.Quick crisp throttle.

I use a 4-blade modified carb because was easier to do.

But for sure single has more airflow, so , no restrictions and better!

Rob I know where a big single and elbow are, relitivly local too. I can details today if you want.
Steve

[quote} Sorry but single is better. More air flow and quicker response. Tuning is done via a laptop, and should not be done on the mechanical end. Restricting air flow with a restrictive 4-blade, is just that, restrictive...

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Why would you want to do it with EFI tuning rather then airflow. I have heard many complaints from guys trying to use big singles on street cars because they are so touchy. "Quicker response" is what you're trying to avoid. A progressive linkage 4-barrel takes care of that issue.

From what I have seen the big dominator stuff will actually outflow a single blade too. I saw a couple tests on the N/A stuff that the 4-barrel made more power on back to back tests then one big single...

I don't have the answer, but it seems like it would be a pain to tune the fuel/timing map, rather then just slowly opening the throttle blades.

Because you still have to tune the efi no matter what TB you run...A/F for idle is different than A/F anywhere else, and the transition can be tricky depending on the cam and the TB linkage and number of openings. A single isn't linear, more of an exponetial curve, but very predictable, a 4-hole progressive will not be anything even close and can really be a pain to tune with the IAC.

Singles are touchy in full tune mode. They can be like an on off switch, but a 4 link will like the harder hit better. Delaying it mechanically causes other issues too, and you can never really get the throttle response of a single out of a progressive 4 barrel.

For street, you just detune it a little with the VE vs TPS and the timing curve, and it makes it very smooth and not touchy at all. With XFI, you just use a switch that allows you to flip between programs on the fly with no computer.

Besides, as mentioned, four barrel progressive will actually be tougher to set-up, especially with a radical cam.

The boundry layer (0 velocity air) at the wall of the TB barrels restricts flow. Fewer barrels, less boundry layer. Tip in control for the street using a large one barrel TB is usually done by shading the butterfly plates initial 15deg rotation through a casting/billet protrusion into the bore or by using a shaped plate that flows less air at lower actuation angles...A 2000cfm single barrel TB is going to be a whopping 120mm in diameter...I go 2 barrels for that airflow!

Id put a single 90mm on it .

I like them so much I have 2 on my new manifold.

Progressive EFI tuning can be a little tougher than letting er rip with a one or two barrel, but with the right manifold the results are worth it! If its just a 4bbl progressive TB on a single plane manifold, I see no point in a progressive TB. Linkage cams can be tweaked for "foot feel" vs driveability, but its all in the software!

2500 cfm two barrel

Mild....

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Race tune!!!

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