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1991 Acura NSX - Wrenchin'

Against The Grain

Aaron Bonk
Dec 1, 2008

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Honda Tuning Wrenchin Project NSX   Wheels Suspension Brakes Diet
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Author
NSX_Proj
8685 posts
Anaheim, CA

2018 Acura NSX
$156,000 Base Model (MSRP) 21/22 MPG Fuel Economy

Post
Building the NSX My Way And actually driving it
It looks as though I'm what you call an "eager driver." At least that's what a group of NSX owners who rarely drive theirs calls me. Owning an NSX but hardly driving it might be considered cool to them, but I've never pretended to be cool. Apparently there's somebody with a '91 with less than 5,000 miles on it. By my math, he's putting about .76 miles on it a day. He must have a short commute. Contrary to what anybody who's content at waiting for his NSX to hit collector-car status thinks, the NSX was made to be driven-it is a Honda after all, not an Italian supercar that's synonymous with $15K clutch jobs. Since I plan on actually driving my NSX, I've decided to modify mine in a way that makes sense for a car that'll actually reveal itself from its car cover every once in a while, even if I am eager.

Author
NSX_Proj
8685 posts
Anaheim, CA

Post
First things first, the NSX's power-to-weight ratio wasn't too shabby by 1991's standards-roughly 270 hp at just over 3,000 pounds-but not so much by today's. A smog-legal, K-swapped Civic hatchback will put the NSX to shame numbers-wise and in a straight line; you've pretty much got to come to terms with this right off the bat, otherwise you'll be in for a world of disappointment. Heck, let's just admit it right now: Aside from the NSX's titanium rods and twin-disc clutch (NA1 only), the K20A is leaps and bounds more sophisticated than the C30A or C32B NSX engines. Think i-VTEC, roller rocker cams, etc., but nobody's here to talk about the K. On a more positive note, few other cars handle like the NSX, including pretty much anything with a K swap. There's just something about a true, mid-engine sports car that no other layout can offer.

As is the case with most supercars, it really is tough to make the NSX's suspension much better, especially when you consider that this is what Honda prided itself most in when designing the car. Take the '88-'91 CRX for example. We know that Honda made sacrifices on the performance side in order to sell more CRXs. As such, the suspension is a bit more compliant than we'd like, there's slop in the front end, and the spring rates are forgiving. Stiffer bushings and spring rates, thicker antiroll bars, and more aggressive alignment settings are easy and predictable ways to make most any CRX handle better. Apply the same philosophy to the NSX's all-aluminum, double-wishbone front and rear suspension and you might just ruin the Formula 1-inspired experience that Honda spent years developing.

In an effort to not bungle up what Honda perfected, I started simple with just wheels and tires. The fact that the '91-'93 NSX wheel-and-tire package leaves something to be desired is obvious. I mean, look at them: The 15x6.5-inch fronts simply don't fill the fenderwell enough to look presentable, and the 16x8-inch rears are just way too wimpy. It's perhaps the only thing that looks out of place on this car and that includes the pop-up headlights. Unless you're buying the ubiquitous 5,000-mile NSX, you probably won't need to worry about the original tire specs since they've likely been replaced, but if you do buy this you'll notice that it's got Yokohama A022s sized at 205/50-15 up front and 225/50-16 in the rear-hardly an aggressive setup considering how much more you can stuff in the gaps. Speaking of what fits, it's possible to finagle as much as a 20-inch rim out back, but remember, I still want to drive my NSX. The practicality of a 20-inch rim on bumpy SoCal roads is little, not to mention the added rotational mass, which will only allow that Civic to embarrass me even more. No, in order to fill up the wheelwells but not sacrifice performance, I went with 17- and 18-inch Enkei RPF1s paired with 215/40-17 and 275/35-18 BFGoodrich G-force Sport tires. The 17x8 front wheels have a +45 offset, which means I don't need a spacer and I still have plenty of clearance everywhere that matters, like in between the knuckle and the tire and the tire and the fender. The rear 18x9.5s have a +38 offset, which requires a 3mm spacer for brake clearance but affords plenty of room everywhere else like between the knuckle assembly and the fender itself. Best of all though, the cast Enkeis weigh about the same as the OEM rims-15.6 pounds up front and 17.2 pounds out back, that's only .4 pounds more for each front rim but a full 3.4 pounds less out back so, collectively, things are lighter. Discount Tire set me up with the whole package, delivered to my door mounted, balanced, and ready to install. It took me longer to calculate my widths and offsets than it did to have them shipped.

At stock ride height, the Enkeis and BFGs only made the NSX look that much more awkward. I bought the car with a pair of worn-out OEM shocks up front and a couple of tired Bilsteins in the rear. The springs were stock as was the rest of the suspension. In fact, the NSX was hardly ever modified at all and was purchased from the original owner, which was one of the major selling points for me. Coilover choice was an easy one. I've used Buddy Club's Racing Spec dampers before and have always been happy with their construction, adjustability, and overall build quality. The Racing Specs feature 15-way damper adjustability through an easy external dial located on the upper part of the shaft. Settings range from +4kg/mm to a soft -4kg/mm. The Buddy Clubs offer two ways to adjust ride height: I can raise or lower the pair of locknuts that the spring rests on-like with most adjustable coilovers-or I can raise or lower the shock's lower mounting bracket by threading it on or off, which effectively makes the damper shorter or longer, respectively. This comes in handy, especially if I decided I don't want to alter the actual spring's height. Not all coilovers have this sort of adjustability though, which makes the Buddy Clubs special. Aside from the adjustability factor, the Racing Specs also weigh in similar to the OEM setup at 55 pounds and are priced very competitively. Yeah, with such an aggressive drop the camber is affected, but with such a wide tire out back, excessive tire wear is minimal, especially since I was able to dial the toe back to stock settings. Besides, the tires are only going to last about 10K to 12K miles anyways since they can't be rotated. As far as suspension goes, this is it for now. The lower ride height and wider tires were enough to give me everything I thought was missing. Sometimes all it takes is a fresh set of rubber, a firmer suspension, and a lower center of gravity to increase a car's intuitiveness with the driver and road.

Author
NSX_Proj
8685 postsAnaheim, CA

Post
NSX guys like big brake kits but big, heavy rotors and oversize calipers never do much for acceleration. Since I plan on driving my NSX, I opted for something subtle. But first, the previous owner thought it would be cool to paint my NSX's calipers red long before I ended up with the car. The stripping process took a good four or five hours, about five or six pairs of gloves, and an entire bottle of paint stripper. The tricky part was avoiding the calipers' rubber seals and dust boots with the stripper. Once back to their factory-finished look, I swapped on a set of cryo-treated and slotted rotors from Power Slot along with Axxis brake pads and steel-braided brake lines from Goodridge. Why cryo-treat the rotors? Well, Power Slot's regular slotted rotors are great for the street and ventilate gasses and help remove brake dust better than the OEM ones since they're slotted, but their metallurgy just isn't up to severe track duty. The cryo treatment allows me to visit the track on occasion but without having to swap out rotors. How? The process improves the metal's service life by gradually cooling it to 300 degrees F, then slowly bringing it back up to room temperature, and then finally heat cycling it. Cryo-treating redistributes residual stresses throughout the rotors, making them last longer and able to take more of a beating from me. Power Slot offers this service for all of their rotors. Best of all, this semi-track setup weighs the same as the OEM ones, which means I won't be spinning around a big, heavy set of rotors on the street. After all, the 11.1-inch OEM-size rotors provide more than enough stopping power for any street situation and, with the right pads, are quite capable at the track. The Goodridge lines and a complete brake flush using fresh Honda DOT 3 fluid was all it took to firm up the brakes.

Author
NSX_Proj
8685 postsAnaheim, CA

Post
Before having any fun, a bit of previous-owner neglect had to be taken care of. It's surprising that these problems showed up, considering how well the car appeared to be cared for before I came along. For example, the A/C would only blow on its high-speed setting, a pretty annoying problem for when I wanted it on low. Lucky for me this is a common NSX issue, which means the solution is well known. The problem lies in the climate control unit's circuit board, which has a bunch of capacitors (which are sort of like little batteries) that leak acid out onto the board, damaging traces and making things like fan speeds not work right. I suspected the A/C blower motor or transistor first, which would've been a likely culprit were it any other Honda, but some new capacitors soldered onto the board did the trick along with some cleaned-up traces. A new passenger-side window regulator was also installed along with some miscellaneous interior clips, brackets, and hardware. I also replaced the plastic center console cover and center A/C vent cover, e-brake handle and shift knob-together they cost more than a hatchback I once owned.

Next, I needed to make sure my NSX wouldn't get stolen. I contacted Auto Page for its basic RF-525 alarm system and C3 communications module. Basically, the C3 is like any other tracking device, only better. With the C3, I receive an email on my cell phone once any of my preset parameters have been triggered, like if my car moves more than 15 feet without me in it. The best part is that I won't have to wait for the system to start tracking my car until it's been reported stolen. Nope, I can track it right from my computer or even my cell phone anytime I want. Since the NSX was already prewired for an OEM keyless entry system, the installation was quick and easy-no running wires from underneath the dashboard or behind door panels.

Author
NSX_Proj
8685 postsAnaheim, CA

Post
It's funny, but I'm simply not interested in forced induction with this car-not that it couldn't use the power, because it could. Instead, I'll be looking to save weight in a few key places and pick up power where I can, the naturally aspirated way. My NSX didn't come with a spare tire (that's what AAA is for anyways). As such, I didn't see much use for the 8 pounds of air jack and tools sitting in the trunk. A bit of panel removing also netted me more than 12 pounds of factory cell phone pieces, cables, wires, and miscellaneous brackets that I also don't want. I even ditched the OEM antennae assembly for something smaller and that doesn't rise up four feet in the air like something you'd see on a boat. Another couple of pounds was found here. Of course, the battery is another good place to find weight savings. An Odyssey PC680 and lightweight aluminum bracket were swapped in, saving me another 27 pounds. In three months, the PC680 hasn't failed me at starting up once but then again, I drive my NSX, which helps with that whole charging thing.

If you like NSXs, stay tuned. By the time you read this, I'll have yanked out the engine, thrown just about every maintenance part on it Honda makes, and sent it off to the paint shop. Oh, and I'll be driving it again after all that.

Sources

Goodridge
Torrance, CA 90501
310-533-1924
http://www.goodridge.net
BFGoodrich
877-788-8899
www.bfgoodrichtires.com
Discount Tire
855-869-7914
http://www.discounttire.com
Oil Eater
800-528-0334
http://www.oileater.com
Powerslot
(818) 709-4800
www.powerslot.com
Buddy Club
909-923-9188
www.buddyclub.us
By Aaron Bonk
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