| I'm sure the 4bbl TB would flow far to much air out of the box for my engine
| size/mods, but I was thinking that I could get a restrictor plate to cut down
| the CFM to whatever worked best.
I still haven't bought the argument that you can over TB an engine
like you can over carb one. The downsides to a to big tb would be
mainly loss of throttle granularity (e.g. a 1% change with a 4bbl is like
a 5% change with a stock 2 barrel, so you loose some of the "precision").
It's not like a carb'd engine where vacuum over the ortifice meter's fuel -
that's done independently.
As for the velocity argument - the airs going into a plenum - once it hit's
that, boom, it slows down anyway. If it were a velocity stack setup it might
be difference.
I don't think the TB will help much either (at least on a stock displacement
engine) - pumping losses really aren't an issue (which is what the TB helps) with
the CFM that would be turning.
I think a restrictor plate would be more trouble than it's worth honestly. If
you want the 4bbl just do it - you probably won't pick up any power, but it
shouldn't hurt anything. I would definitley consider the progressive linkage
that Brend mentioned earlier!
| Any chance you could post a picture of the mod you did to the 4bbl TB to
| adapt the TV cable?
| Also, what engine setup are you running (ie. year, cubes, mods, obd 1 or 2)
| In addition, what valve sizes do you recommend?
I will try and get a picture of it and post it - I really just drilled a small hole,
tapped it, ran some threaded rod in it, and fixed the TV cable connection
over it. But will try and get some pics.
Old engine was a 318 with heads+Cam, M1. OBDII, but has a haltech DFI
piggyback computer that handles fuel and spark. New engine is a solid
roller 408.
Valve size I would stick with a 1.625 exhaust, no reason really to go bigger.
On the intake I would like a bit more valve, but honestly anything bigger than
a 2.00 valve and I don't think you can do a good valve job. My head porter
tried first with a 2.02 and with a 5angle valve job hit water (not good). Honestly
with a good valve and valve job you aren't giving up a whole lot with the smaller
valve, and on a smaller cube motor it's definitley the way to go anyway (try
and keep velocity up).
Chris Bennight
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