Contour Enthusiasts Group Archives Forums Modifications Duratec Performance 70 MM Throttle body.

Actually, I heard it wasn't that bad. LOL! Anyway, if you're feeling froggy anytime soon, the offer still stands.

I'll keep that in mind, thanks!

still waiting on pics or performance gains on this setup....um has something gone wrong

No...Nothing has gone wrong. I just had to deal with a week long fiasco at the dealership. They couldn't seem to get the right main cat. I just got my car back on thursday. I have a dyno appointment this Friday.

--Matt

Steve- not sure if you are aware of this but casting a larger tb is a hell of a lot cheaper then dumping a LSD in all the svts... also i don't think we didn't get a baffeled oil pan because of cost issues... maybe more because of design flaw...

the way i see it the car is sucking in more air then it can use effiently right now, so how would pumping even more air in help? you might see some small gains with a larger tb on a car with some extensive exhaust work done, and a dyno tune. but i doubt just adding a larger tb is going to give you anything... like i said before, i bet he sees a nice loss in low end torque.

[sarcasim]
Gee, I wasen't aware that it would be cheaper to design a new TB than it would be to get a LSD.
[/sarcasim]

You totally missed the point of my post. I was saying that your reasoning of "i just doubt roush would go thorugh the trouble of using a larger tb to obtain more hp, and not max it out..." was totally stupid. They had a larger TB at their disposal with essentially no design costs other than bolting on a new cable bracket, so they used it. It was hardly a breakthrough in engine flow dynamics when they said "hey, let's use a 60mm TB on the SVT". My comment of a(n) LSD or baffled pan was purposely exaggerated to prove a point (just because they didn?t do something dosen?t mean it isn?t worth doing).



First off, don?t use the term ?pumping? when describing a naturally aspirated engine.

Go back to my previous post. At low speeds, when the primary intake runners are being used exclusively, the engine is limited in the torque it can produce by the size and potential flow velocity of the primary intake runners. For the time being, let us say that the 2.5L Duratec has primary runners that are correctly sized for the engine?s displacement. Make them larger and velocity slows down, (theoretically) decreasing low-end torque. As long as the TB is supplying sufficient air volume to the intake manifold to feed the runners, TB size is a non-issue.



Um, drugs are bad, mm-kay?

I guess I'll have to get with Steve B. and AussieSVT about the TB mods. I'm wondering if both the 65mm and 70mm have the same gains. Can you guys tell me what the partnumbers I need are? I would like to look into this since I have some extensive exhaust mods.

I'd say go for the 65mm, you can get them for cheap from the 4.6 Mustang guys.

Nice thing about 65mm is that the SVT upper intake is already 66mm (measyured by someone) so no opening it up is required.

Some thoughts on "optimal size" for T.B. (which I admit I do not know)
1) stock exhaust is 57mm (2.25 inch), so going to 65mm may need to be accompanied by a 2.5 inch (63mm) exhaust. So this may suggest that 70mm may not add anything over 65 with >2.5 inch exhaust.

2) The stock 70mm MAF actually has a bar in the middle (holding the sensor) that looks about 10mm wide. Thus the MAF may only flow like a 60mm. Again would think that upping MAF size may be important in gaining benifit from >60mm T. Bodies.

Just throwing stuff out, this is an interesting thread.

You are correct, Dan.

I'm running an 80mm maf with my 70mm tb, and the combo works quite nicely.

Midrange improvement is amazing, but the top end is still kinda soft. I expect that when I install headers in a couple of weeks and possibly yank the imrc, the top end will get very sweet indeed. As it is, my catless euro manifolds, as nice as they are over stock, are limiting upper rpm breathing.

We'll see...

Dan Beggs
99 Cougar V6, lottamods