Ported 65mm Throttle body

Hey guys,

I've been looking at various different routes to pursue for getting a new TB for my little build up . . . seems I don't have much choice but to bite the bullet and pay up as they're all expensive, but I did find a "bargain" that I might consider buying.

It's a ported 65mm throttle body; I guess it'd be easier to just cut and paste the ad:

"65MM BBK/EDELBROCK Throttle Body and EGR Spacer that was PORTED for more performance. The blade shaft was reduced and Stainless Steel countersunk screws were applied. Next, the (bore opening) was then opened to 82mm and tapers back down to 65mm and then throttle body was completely cleaned inside and out. This allows this throttle body to flow better than when it came from the factory by reducing turbulence from the blade shaft which increases airflow. Next, the throttle linkage was painted gloss black to get rid of the bright gold that comes original from BBK. This throttle body looks great and flows better than new so whats not to love. This also comes with a matching 65mm EGR Spacer plate."

Yeah it sounds good, but I'm not so sure about this porting, and in fact the TB/EGR spacer is rather cheap ($120) if it's really that great. I have heard that turbulance in the intake charge can be desirable and increase HP/efficiency, and I suppose that maybe this port job could create a venturi effect and help out? One of my buddies thinks that I should steer clear of this TB, but as knowledgeable as he is of building motors I don't thnk he knows a whole lot about F/I. All the same, my H/C/I swap and intake/ FI upgrades have gone over budget, and any more money that I spend will likely leave me eating ramen noodles till the end of my semester; not to mention that my shocks/struts are blown so I'll likely wrap my car around a tree before I get used to the >100hp I expect to pick up if I don't address the suspension as well.

My point is, I can't afford to waste money, and I'm wondering if I should take a chance on this TB . . . oh and BTW it says BBK/Edelbrock . . . wtf? I thought these were 2 completely seperate companies, am I missing something?

dcurtis said:

If it was already a 65mm it doesn't really make since as to why only a portion was ported to 82mm, either way the air is still traveling through a 65mm as the ad states that it tapers back to 65mm Doesn't sound like it would be any different than a stock 65mm. Basically, ported to 82 on the inlet side and still being 65 on the other doesn't make since, the air still is going through a 65mm opening, not 82, I'd pass on it and buy something else.

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A 65mm TB is still an upgrade from what I have, and a necessary one at that to support everything else; as far as the 65-82-65mm thing the only possible benefit that I could see is a sort of reverse venturi effect that maybe increases air velocity and turbulance going into the intake, which I guess is a good thing, if it works . . .

Maryland Stang said:

The turbulence thing you're talking about usually has to do with carb'd intakes and keeping the fuel in suspension. It has little to no effect on F/I cars and may do more harm than good.

The reverse venturi effect you're talking about is called the Bernoulli Principal.

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I guess that makes sense, being upstream of the injectors and all, I'd heard that turbulence in the intake ports of the heads could be beneficial.

Bottom line: would I be better off getting another 65mm throttle body or a 70mm throttle body than this one? This would support the following: 94-95 70mm MAF, 3.5" Powerpipe, Exploder intake, mildly ported E7s, E303, Bassani x-pipe and flowmasters, everything else stock (possibly new headers in near future).

dcurtis said:

Regardless of air velocity the opening is still only 65mm, opening up the inlet does no good if it still closes to 65mm, if you want a 65mm for cheap just look on ebay, there are tons of them on there, don't buy one that has been hacked.

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OK, seems to be a consensus that this would be a bad buy. It's just frustrating because I'm just about out of money and I can't find a new TB for under $200, let alone one w/ an egr spacer, used I don't see anything going for less than $125 (without the spacer), this one is $120 w/ the spacer . . . of course, there's a lot that could prevent my motor from running correctly w/ my build, this would be one more thing to wonder about if I end up w/ problems

dcurtis said:

For the most part the Bernoulli Principal has to do with (liquid flow) not air flow, or oxygen.

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Don't you mean fluid, which air technically is? (It's been a LONG time since high-school physics . . .)