This howto was taken from Lake Effect Racing with permission of the owner.
Installation with Photos | Performance Report
Nemo's Modified Throttle Body
When I called Nemo Foss, of Nemo's Neon Performance, to ask if he had any new go-fast parts for the Neon he sent a throttle body for us to test. The TB looked just like the stock throttle body, except for the larger bore and the blue throttle plate inside it. The stock throttle body has an hourglass shape inside the bore, and a maximum diameter of approximately 52mm. I wasn't able to measure the diameter at the throttle plate of the stock TB, but it is significantly narrower than the ends.
The modified TB has a straight bore of 56mm, and the throttle plate has been replaced with a larger blue anodized version. The bore can't be made any larger and remain round, two vacuum passages will be compromised and then who knows what will happen. There is a number stamped on the side of both throttle bodies, and they don't match. Perhaps they are a serial number. Both throttle bodies were cast by Weber, a well-respected name in fuel-management.
The installation of the TB is very easy, it took a full 10 minutes the first time, around 8 minutes after that. Full installation instructions, complete with photos, are on a separate page. Only two things about the installation really deserve special mention. The TB gasket doesn't need to be replaced, at least it doesn't on a 1997 SOHC. It's a rubber 'O' ring of sorts and works really well. At first I was surprised that no local dealers had a gasket in stock, after seeing the gasket I know why. The second observation has to do with the intake manifold. If I were keeping the TB, I'd enlarge the intake hole about 2 mm to match it's size to the TB's 56mm.
In the lower rpm range the car feels a little jumpy, but after a few miles I was able to smooth out my throttle application enough that the car didn't start to 'buck' at low speeds in first gear. That same jumpiness also makes the car a lot more fun in third and fourth gear where it shows itself as instant throttle response. I did the formal testing at wide open throttle, but the TB affects partial throttle response equally well. Around town and expressway driving left me wishing that Nemo didn't want his throttle body back. The modified TB will help a car with the stock intake at partial throttle, but it's effects are diminished by the restrictive intake at wide open throttle. The addition of a Kirk Intake to the stock TB makes a measurable improvement, but the combination of the Kirk Intake and the modified TB improves peak acceleration in first gear by 10% and in second gear by 11%. For a complete rundown of the test and results, check out the performance testing page.
I didn't ask Nemo what he's charging, and he didn't tell me, but a modified throttle body is definitely on our list of 'must haves' for the One Lap motor. An aftermarket intake is also a 'must have' to realize the full potential of this throttle body.
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