Modifications

Where can I find after-market upgrades for my Vigor?

Not too much is available. You can check the Links section, but in all honesty, there's not much there. The Vigor was a low production automobile (approximately 32,000 built over the three year run), so not many aftermarket manufacturers bother with it. It's mostly a Do-It-Yourself proposition.

For example, you can modify your Vig to accept a "universal" K&N filter, but they don't make a "drop in" for the Vigor. See Where can I get an air intake for my Vigor? if a K&N filter interests you.

 

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Where can I get clear corner lights?

You can't. You'll have to make your own by cutting them apart with a Dremel tool, removing the amber diffuser, and gluing them back together.

First remove the lights; then remove the rubber surround from the lights.

Select the thinest cutting blade that came with the Dremel tool and carefully, at the highest RPM, start cutting along the edges where the clear meets the backing. Be careful not to cut off too much because you'll have to seal this again.

After cutting all the way around you will be able to pop the lens open and see the amber diffuser. Break it off with pliers or some other tool (try to do it in one peice).

Use expoxy type glue (the kind that comes in two tubes—make sure its ultra clear) to put the lights back together. You'll have to let them dry a while, then reinstall the rubber surround and glue it in place. Let it set overnight and reinstall in the car.

 

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Where can I get the one-piece headlights I see on Japanese models?

You may notice in some pictures that some Vigor’s have one-piece headlights while most have a 3-piece assembly. The one-piece headlights are original equipment on the Japanese Domestic Market (JDM) models.  Assemblies from the Honda Vigor CC2 (1992-1994) model will fit the US version with modifications.  Assemblies from the CB5 Honda Vigor (1989-1991) will not fit Acura Vigors. Both types can been seen on eBay, so pay attention if you intend to buy a set.

The May 04 Timely Topics article, JDM Headlight Conversion, by Vigor856, shows how to do the changeover. It involves some re-wiring, but it looks really sweet. Docsteen1 didn't want to cut any wires on his beloved Vigor so, for a Dec 06 Timely Topics article, he devised a Plug & Play JDM Headlight Conversion procedure.

And—as if that's not enough—our founder, Texan_176, showed us in the Apr 07 Timely Topics article how to do a genuine HID Headlight Conversion!

 

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Where can I get an air intake for my Vigor?

You'll have to make your own. Go to the House of Vigors to see how Tominizer did his. Click "Vigor Modifications" and then click "Air Intake" and you'll see illustrated, step-by-step instructions for installing a K&N cone filter and a cold air intake system.

Beware of installing a cold air intake that sits too low to the ground. If you go through a puddle, the intake can draw in water, causing your engine to hydro-lock. An expensive re-build will follow.

Also, understand that this will not improve your engine's performance.  Anything you do "before the throttle plate" isn't going to have any appreciable effect on breathing unless other modifications are done first. So, do it if you like the look, but don't expect much else. See the discussion on air baffles for a more thorough explanation.

 

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I'd like to install a set of coilovers. Any advice?

Check out RonaldBrownJr's club site. It's called Ack Repair. He has step by step photos to guide you through the mod. I

 

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Performance

I noticed the Vigor intake manifold has two paths, controlled by a Bypass Control Valve. When the valve is open, the engine has more power. If I "fix" the valve so it stays open all the time, will I get more power?

No, at least you won't get what you're looking for. An ordinary intake manifold's geometry will favor either high-speed power or low-speed torque... or else it will be a compromise. The Vigor's two-stage manifold allows it to deal better with the the breathing requirements at different engine speeds. The effect it has on engine breathing is very similar to variable valve timing, which Vigors do not have.

It's easy to see why the shorter, high-speed manifold is better for high-speed power. It gives better engine breathing because it's a shorter path—it's more direct. Plus its shorter length gives it a higher resonance frequency, more in line with the breathing requirements at higher rpm's. So why would you want to make it longer?

Technically speaking, the longer, low-speed path results in a lower frequency air mass reaching the cylinder. Ideally, the frequency of this pressure wave should match the engine's rpm. This will help "fill" the cylinder with air, improving torque output. The longer path also causes a somewhat slower air flow, which gives better mixing between the air and the fuel at lower engine speeds. This contributes to better low rpm combustion. The overall end result is better low end performance.

This set-up is common in high-performance sedans, where you want the low-speed torque to get the car's weight in motion quickly, but you still want high power at high speeds. Some exotics use both variable air intakes and variable valve timing.

So don't disable the valve. Doing so won't help your high-end performancethat's when the valve is open anyway. It'll only reduce your low end performance and cause a rougher "fast idle" when the cold engine is first started.

 

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If I remove the air baffle, so the engine gets more air, how much more power can I expect?

None. The engine won't get any more air. The air baffle has no appreciable effect on engine breathing— nothing "before the throttle plate" does on a stock Vigor engine.

The amount of air an engine can breathe is what "determines" its power. The more air it can breathe, the more fuel it can burn. It's the BTU's from the burned fuel that translate into horsepower. So, all other things being equal, more air equals more power. But all other things being equal, the limiting factors for breathing (on the intake side) are...

  • The cross-sectional area of the throttle body and intake manifold—larger area equals more air. As the throttle plate closes, the cross-section is reduced, and vice versa.
  • The geometry and length of the intake manifold—this determines its volume, but also its "resonant frequency," which should IDEALLY match the engine rpm. When a pressure wave reaches the intake valves while they're opening, the combustion chamber will "fill" better. If the pressure wave bumps up against a closed valve, it reverses direction and tends to fight the next incoming pressure wave. This air flow disturbance can adversely affect breathing.
  • Valve geometry—the bigger the opening, the more air the engine can suck in. But bigger valves equals more mass to move, and that limits rpm's. Having the valves travel farther also limits rpm's. (Hence, the Vigor's dual intake valves—each valve has less mass and less distance to travel at higher rpm's.)
  • Valve timing—in this case, to exploit the intake resonance so the engine can start sucking in the air at just the right time on the piston's "intake stoke."
  • Compression ratio—this is the difference between the maximum and minimum combustion chamber volume (ie., piston down vs. piston up). It determines the maximum amount of air that the engine can gulp. Further gulping is impossible with a normally aspirated Vigor engine.
  • Compression—if the engine is leaking internally, it can't develop the vacuum it needs to suck in the air.

This is what's happening on the intake side to affect volumetric efficiency—that's the ratio between the actual amount of air an engine sucks in and the total amount possible. The higher the VE, the higher the potential horsepower.

Unless/until the "cross-sectional area" of the intake path is increased, there's not much you can do that will improve breathing—that geometry is limiting the VE much more than any baffle or filter.

Further, to make use of any improvements on the intake side, modifications must be done to the exhaust side as well—that's just basic physics—the engine can't take in any more air than it can push out. Once these are improved to a certain point, then the engine's compression ratio becomes the limiting factor.

Anyway, this is just a long-winded way of saying that the air baffle (Honda/Acura calls it a resonator) isn't affecting performance one way or the other. It only affects the sound of the intake. Take it off if you like the sound, but your car won't go any faster.

 

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What kind of performance improvement can I expect with platinum-tipped plugs?

None. Platinum-tipped plugs don't improve performance at all, they just last longer because they don't erode as quickly. If you notice a performance improvement after switching to platinum-tipped plugs, it's because your old plugs were worn—new copper plugs would have given the same performance improvement. Here's what's going on:

(L) New plug. Note squared off center and side electrodes. (R) Worn plug. Note rounded center electrode and cupped side electrode. This changes the plug gap.

When a plug erodes, its center electrode wears down at the edges, causing it to become rounded. As the side electrode (also called the ground electrode—the bent one) wears, it forms an indentation in the metal directly across from the center electrode, right there where the spark jumps across. This results in gap growth, where the spark gap gets wider as the plug wears. A wider gap requires a higher voltage from the coil in order to spark.

Clean, sharp edges on both electrodes help focus the electrostatic energy from the coil. The sharper the edges, the lower the voltage required to fire a spark across the gap. So, all in all, as a plug wears, it places a higher demand on the coil.

Platinum-tipped plugs perform exactly the same as conventional plugs when they're first installed. They cannot increase the engine's performance. However, they're able to maintain that same level of performance longer.

Note that some platinum-tipped plugs have only a platinum pad on the center electrode. The side electrode is "conventional." In a comparison study conducted by Motor magazine, when examined after 58,000 miles, the center electrodes on these plugs showed virtually no erosion. But the side (ground) electrodes...

"...were eroded by about 25%... What happened is that the erosion shifted from the center to the ground electrode. If the claim for platinum plugs is that they eliminate gap growth, it isn't true in all cases."

This study found that the side electrodes of these plugs were actually worn more than the side electrodes of conventional plugs. Since there was virtually no center electrode erosion, however, these "half-platinum" plugs still lasted longer than conventional plugs.

 

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How about Iridium, Split Fire, and +4 plugs?

In terms of benefit, iridium plugs are similar to platinum plugs. They'll last longer than copper, but they won't give you any performance improvement. They'll withstand the higher heat of a high-compression racing engine, but so will a copper plug that's one or two heat ranges colder than stock. Iridium plugs last longer, but they won't make your car go any faster than copper.

Splitfire plugs actually have some promise for increasing gas mileage in a granny driven car, but no performance gains. The side electrode is the same as a standard copper plug, but the tip forks like a snake's tongue. (See pic at left.) This allows the spark to pass through the fork to reach the mixture, allowing for a larger spark front—provided they're given enough time to cool off, since the larger spark front generates more heat. In racing applications, you'll have to go 3-4 heat ranges colder than "normal" to get them to last. At that point, the tips start to carbon up, and there's really no middle ground with these plugs.

+4's are a Bosch® "innovation." Instead of one side electrode, there are four. (See pic at right.) While that may sound "better," consider this: in the real world, the tip will send a spark to only one electrode per coil cycle, and that's the electrode that's closest to the tip (they're impossible to gap evenly). This leaves the other three electrodes to slowly carbon-up and become useless, until the electrode that's getting all the spark gets wears down farther (from the center electrode) than another one, and then that one will start cleaning itself up and eventually take over.

 

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What are the advantages of cross drilled and/or slotted rotors?

Pretty much just for better looks these days. Originally, the cross drilling and slotting was for releasing gases that built up as the pad scrubbed across the rotor... the pad could actually "hydroplane" on this layer of gas above the rotor. As a side benefit, the holes also helped with cooling. But as with many early technical problems, the myths die hard. Fact is, with modern pad and disc materials and surfaces, none of these factors are really a problem anymore. Exception: bargain brand brake products. Stay with genuine Honda/Acura parts or other reputable, high-qualty OEM-equivalents and you shouldn't have any brake problems.

Also, cross drilled rotors are prone to cracking under unusually high heat. Not good.

 

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Can I compute Horsepower from timed track results?

If you know the vehilcle's weight and either its mph or elapsed time in a standing-start quarter mile, these equations, from Road & Track magazine, should get you within 5% or so.

HP = weight ÷ (ET ÷ 5.825)3

HP = (mph ÷ 234)3 × weight

 

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