From Road & Track, xxx 1971
Caution: This is an old article. A lot of the information in this article may be considered out of date or
just plain wrong.
Ever since the days of the Lotus-Cortinas, I’ve found boxy little high-performance sedans appealing and I suppose that’s why I like the Datsun 510. Its solid sohc 4-cyl engine and independent rear suspension system, not usually found on economy sedans, give it lots of performance potential. It is the 2.5 Trans-Am champion (with a little help from Pete Brock and John Morton) and is quickly becoming popular in SCCA B Sedan racing. As a result of this racing activity and the increasing popularity of the 510, much high-performance equipment is being developed, and one of the main sources for such equipment is the Datsun factory.
Racing parts engineered by Nissan are availiable over the dealer’s parts counter by way of the Datsun Competition Department. The Competition Parts Department doesn’t sell the parts directly but has a separate warehouse from which the parts are shipped to the dealers. This department does deal directly with the customer, however, when offering technical advice and distributin competition parts catalogs. These are factory parts, most of them homologated for production-car racing, and the factory backs them by including them in the new car warranty. If a dealer installs the part, from L16 SSS cylinder head to the factory racing suspension kit, the warranty is still good – until the car is raced. It is conceivable, then, to have a highly modified 510 and still have the warranty in effect. It is a unique situation, great for the enthusiast and made possible because Yutaka Katayama, president of Nissan Motor Corp. in U.S.A., likes racing and feels that success in racing will improve sales.
Then there is Pete Brock, who has a winning way with Datsun cars, collecting the C Production championship two years in a row with a 240Z and winning the 2.5 Trans-Am with a 510. The equipment Brock Racing Enterprises designed and developed for the Trans-Am car is available, and now that the season is over BRE is filling in the gaps by designing suspension and engine packages for street use. In fact the parts business has grown so much that Brock has formed another company, Interpart, to handle sales and distribution of BRE parts as well as Nissan factory competition parts.
We caught Brock and chassis expert Trevor Harris in the middle of designing a street/slalom suspension kit for the 510 and arranged to test a prototype of the kit. Our baseline on the skidpad for a stock 510 was 0.611g lateral acceleration, limited by the skinny tires and rims. Simply changing to the dealer-installed 13 x 5 1/2-in. rims and 165-13 Bridgestone radial tires jumped the figure to 0.739g. That brings us to the first step in improving the 510 – wheels and tires. They are the best possible investment for improved handling and bracking and should be the first step, as the original equipment here is strictly economy. Tires as large as 185/70-13 mounted on 13 x 5 1/2 or 6-in. rims will fit without rubbing the fenders (providing the wheels have zero offset), even with the car 1 1/2 in. lower than stock. Many of the wheels sold for 510s have too much offset and limit the size of tire that can be used. The wheel manufacturers now have realized this and have begun to make wheels with proper offset.
With the baseline tests complete, a prototype of BRE’s Phase III Mulholland suspension kit was installed. The kit includes shorter, 115-lb/in. front and rear springs (stock springs are 85 lb/in.), 15/16-in. (0.94-in.) front anti-roll bar, 3/4-in. rear anti-roll bar and Koni shock absorbers; this lowers the 510 about 1 1/2 in. but keeps the center of the headlights a California-legal 24 in. above the road. Harris replaced the stock, rubber-mounted drag struts, which connect the leading edge of the lower front suspension arm to the body with a pair of ball-jointed struts. These eliminate rearward compliance in the front suspension and result in more positive steering feel at the expense of ride harshness. Using the ball joints these struts sell for $100 a set, but BRE is experimenting with Teflon to get the price down. They are not listed in the Interpart catalog yet. The suspension kit without the struts sells for $240, but it made a $2000 difference in the car and upped the skidpad number to 0.808g, still on the 165-13 radial tires.
Goodyear A70-13 bias-belted tires on 13 x 7-in. 4-spoke American Racing wheels were then bolted on a brought the lateral acceleration to 0.823g, at which point the stock carbuetor gave up. The non-baffled float bowl couldn’t handle the load and caused the engine to cut out after two laps but this problem never appeared in normal driving. The ride with the Mulholland kit is slightly more harsh, but not as harsh as the factory racing suspension and although wheel travel is reduced somewhat, the benefits in handling are certainly worth the loss for those not concerned with rough-rod or full-load ride and handling.
We ran two additional suspension tests. A 510 with the factory suspension kit (new front struts with springs, rear springs, shocks and a 23-mm, 0.91-in., front anti-roll bar) and Bridgestone racing tires on 13 x 5 1/2-in. rims went around the skid pad at 0.826g. This car, with two sidedraft Mikuni-Solex carburetors, had no difficulty with fuel delivery. And BRE’s number 35 Trans-Am car, during a shakedown session, went around at 1.01g on Guddyear racing tires.
“What modifications can I make and still run my car on the street?” asked Bruce Armstrong, an energetic young Datsun dealer from Yuma, Arizona who had just come into the BRE shop. “I’ve got just the thing sitting on the dyno right now,” replied Pete Brock, “Let’s see if it’s right for the street.” The dyno engine with L16 SSS cylinder head, BRE 311 cam, factory 9.5:1 pistons, Mikuni-Solex carburetors, tubing exhaust headers, strengthened rod bolts, light alloy flywheels, competition clutch, single-point distributor with special coil, points and resistor was quickly installed in Armstrong’s 510 which already had the factory racing suspension and Bridgestone racing tires. It worked. So well in fact that Armstrong bought it. Armstrong, now with a Datsun agency in New Westminster, Vancouver, B.C., has over 6000 miles on the engine and it’s still going strong and getting 22 mpg. Now with a 5-speed transmission installed in his car (“It keeps the rpm down over 100 mph”, he says) the fuel economy is slightly better. His 133-bhp Datsun is so docile that his mother asked him to build her a slightly detuned version, which he did with factory racing suspension, 9.5:1 pistons, 311 camshaft, tubing headers, Offenhauser intake manifold with stock carburetor, DS11 brake pads, Datsun 2000 clutch and a BRE front spoiler. It’s the fastest, best handling Datsun 510 in town,” she says.
For those who can’t afford 133 bhp, there are steps in between. An assortment of camshafts, pistons, tubing headers and carburetors is available, but the L16 SSS cylinder head, part of a regular production model called the 510 SSS and not available here, is the key. Adding all the equipment available won’t improve a thing and, in fact, may actually hurt the performance of an engine with the stock cylinder head. A stock engine with a good tune-up, rejetted carburetor and perhaps the single-point distributor does a good job and that’s as far as some owners will want to go. To go beyond that the head must be replaced.
Factory 5-speed transmissions are sitting on the parts shelves for those who are serious ($355) about going racing or high-speed touring. Installing the 5-speed requires a new driveshaft ($65) and rear transmission mount ($23.75). Limited-slip rear ends in rations of 4.11, 4.38, and 4.63:1 are factory supplied ($170) and a limited slip is a good investment for those who drive hard. Study the catalogs and ask the firms specializing in Datsun parts – Datsun Competition Department, BRE, Bob Sharp Racing and Ray Reed Racing – for advice. They can help you build a better 510.
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