Any gains from larger throttle body? 96 Mustang GT

Will there be any noticeable performance gains from installing a larger throttle body on my 96 Mustang GT? I believe the stock size is a 65mm. I am debating on installing a 70 or 75mm throttle body. Car is essentially stock minus 4.10 gears and a shift kit. 64k for miles.
 
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698
Location
Fontana, California
I'd save the money and put towards something else, unless you are scoring the part used on a good deal. Throttle response is improved for sure, but that's about it. It will be harder to fine tune your city driving and your mpg's will actually drop slightly as you give it too much and let off more. I went with a 70mm on my 1989 5.0 mustang. Until the heads came off and it became another animal, i regretted the TB. Even now a 65mm would have been fine. Such low miles on that car, I'd base kit supercharge that thing with water injection, a stout tune and not look back. If something bad happens you will rebuild taking lots into consideration and with a the new build you'll need the bigger TB. Yes I'm a mustang guy at heart, weird to have gone 5 years w/o having one on the road. Kids do that to you.
 
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43,772
Location
Ontario, Canada
On the 4.6L, especially the non-PI version like you have, I wouldn't be worrying about the TB, I'd be worrying about getting the parts to do a PI swap
 
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Ohio,USA
It's unlikely, unless the TB is the primary flow restriction from the airbox to the tailpipe. You've really got to look at the system as a whole. Most cars benefit more from better flowing airbox and exhaust systems. Just don't go too big, as that's the biggest mistake most people make. Components with maximum flow numbers that are simply too large will result in drastically reduced velocity in the normal RPM range. This gives you an engine with a powerband biased toward maximum revs and lousy drive-ability in the real world. If you're interested in doing performance upgrades to your engine, I'd suggest looking at some of the matched component sets that are available. They've been optimized to achieve maximum performance within a predetermined rev-range. Edelbrock is just one name that has done a lot in this area. Another thing you might want to try is a "simulator" program, which allows you to see what various changes will do to an engine. They have become quite sophisticated and can provide some excellent insight into what works and what doesn't. It sure beats wasting money on something that you later find has only managed to turn your car into a dog...
 
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14,727
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Santa Barbara, CA
the best thing you can do with a 96-98 is the PI head and intake swap hands down. takes about a weekend taking your time and you get significant gains. i had a Accufab 70mm TB and upper plenum on my 98 and it felt like it gained a little bit, but nothing magical. i gained more by putting on a Bassani offroad X pipe.
 
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43,772
Location
Ontario, Canada
The gain anything from the TB, you need the rest of the parts. Intake, cam and heads. So, those swapping larger TB's onto their stock engines, well it doesn't surprise me they didn't notice anything. I have a 75mm TB mated to a TFS-R intake on the 302 in my Capri. TB matches the port opening on the intake. Tubing is a 4" AFM Power Pipe mated to a 90mm LMAF. Definitely go with the PI swap, you'll see the most gains there. Alternatively, you could do a 32V swap, as there is another boardmember here who has that done, and that gives you even more power!
 
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39,806
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Pottstown, PA
Finally- a group of people who realize that it mostly reindexes your throttle geometry. You get more opening per/mm of foot movement. This is a hard argument to present when you're between a man parting with his money. I guess for some engines you could get something @ WOT at the upper CFM levels. Some minor difference in VME ..but it appears that everyone here has already worked out the R&D on that end of things.
 
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Guilford, CT
It's a total waste of time unless maybe you spend a lot of time at WOT. If you need more airflow, just step on the gas some more! The throttle plate will open up, letting more air through.
 
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Location
Central Coast, Calif.
Seems like a smaller pulley/cam for the throttle cable on the TB would get the same effect until WOT. The car would be "more powerful" or have "quicker throttle response" without actually having either.
 
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Florida, Cape Coral
I would think that the initial engine response would be poorer due to reduced velocity in the intake track. However someone pointed out that the TB may not be the restrictive part.
 
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43,772
Location
Ontario, Canada
 Originally Posted By: Eddie
I would think that the initial engine response would be poorer due to reduced velocity in the intake track. However someone pointed out that the TB may not be the restrictive part.
I noticed no response issues with my 75mm. Remember, modulation for the blade is changed up as well on (most) larger TB's.
 
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Chicago Area
If you put in hotter cam[s] and a bigger exhaust, a larger TB may be of value. But rarely is a stock or near stock engine in need of a larger TB. It would only be of value at wide open throttle, and high RPMs, anyway.
 
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Ontario, Canada
 Originally Posted By: Eddie
I would think that the initial engine response would be poorer due to reduced velocity in the intake track.
I would think so too but in the 1st gen Neon's case they put a smaller throttle body on the manual trans cars, vs the autos, to reduce the initial lurch that happens when you crack the throttle. Anyways, one of the first mods on a manual car is to get an auto throttle body or a bigger one from caravan. I wonder now too with port fuel injection that the air velocity at the throttle plate doesn't matter much anymore? It not like its a carb mixing fuel in right there. I'm sure there must be a mustang forum where almost everything has been tried and people have reported what works and what doesn't.
 
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43,772
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Ontario, Canada
 Originally Posted By: IndyIan
 Originally Posted By: Eddie
I would think that the initial engine response would be poorer due to reduced velocity in the intake track.
I would think so too but in the 1st gen Neon's case they put a smaller throttle body on the manual trans cars, vs the autos, to reduce the initial lurch that happens when you crack the throttle. Anyways, one of the first mods on a manual car is to get an auto throttle body or a bigger one from caravan. I wonder now too with port fuel injection that the air velocity at the throttle plate doesn't matter much anymore? It not like its a carb mixing fuel in right there. I'm sure there must be a mustang forum where almost everything has been tried and people have reported what works and what doesn't.
There are a number of them and I'm members of almost all of them. The best (for tech) has to be SBFTech.
 
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Olathe, KS
I find this thread interesting. I was considering an aftermarket TB for my 4.6 3V Sport Trac. People who have them, swear by them. Now, I'm not sure. Maybe I should spend an extra $100 for SCT tuner (w/3 tunes) first? (Didn't mean to hijack.)
 
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