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The Merkur XR4Ti IMSA IS (International Sedan division) race car was built and campaigned as a privateer effort by Bill Topping of Maryland (and later Georgia). He raced it full time in IMSA for the 4 years 1988 through 1991. The car is listed, and is in some of the action photos, in the IMSA yearbooks for those years. All of the entry/tech stickers are still on the A pillar roll bar.

As allowed by IMSA rules the IS cars were more advanced (and faster) than the Firestone Firehawk series field. There were a few factory backed teams and well known drivers in IS as well. Many races had broadcast television coverage.

The International Sedan division rules allowed numerous chassis modifications but limited drive-train improvements. The Ford 2.3 liter turbocharged motor remained mostly stock with the allowance to add an intercooler (XR4Ti's were not factory intercooled). Stock XR4Ti's could easily exceed the factory stated 195 hp which combined with weight reduction and superb handling made the car very fast.

Topping started construction of the car in 1986 and completed it in 1988. It was a complete ground up construction from the bare unibody shell up. Every inch inside and out was stripped and prepped. The car received a full cage, gauges, Accusump, fuel cell, fire system, Tilton/JFZ racing brake system, custom shock tower camber plates, adjustable coil-over front struts, adjustable lower radius rods (compression struts), custom sway bars front and rear, heim joints everywhere, intercooler, oil cooler, plus lots of really trick pieces and modifications too numerous to list. Weight is around 2,500 lbs. Topping hand built the car himself and the workmanship is outstanding.

The car ran well in the top half of the pack at numerous tracks in the eastern half of the country and as far west as Topeka and San Antonio.  The '91 season was the last year IMSA allowed turbocharged cars in the IS class, and then only if the car had been run in the prior year.

The car was stored from '91 through '96 and then purchased by Peter Cipolla of Kansas City, Missouri. Cipolla found the car in excellent, run-able condition.

Since 1997 Cipolla has gone through the car completely, yet maintained the integrity of the car as Topping built it. One exception was to install a larger intercooler to support the increased horsepower the engine produces today. To date the total development costs in the car exceed $70K.

Cipolla also owns the Merkur XR4Ti IMSA GTU race car that was built for Ford by Kent Racing of Hawthorne, CA and campaigned during the 1985 through 1988 seasons.

The Merkur IS and GTU cars are documented in the IMSA yearbooks.

Cipolla runs the IS car on-track frequently, primarily at Ford/Shelby club events around the country. It still runs well into the top half of the pack against a field of V8's!

October 2006
Bill Topping race photos:
Photos courtesy of Mark Windecker
Left: Road America, July '89. Early graphics and distinctive 'vented' parking lenses.

Right: Heartland Park Topeka, May '91. The car is substantially further developed at this point (as I'm aware of from the tons of spares (take-offs) that came with it).
Recent open track events:
Left: Northwoods Shelby Club event at Road America, September '02.

Right: New York Shelby Club / Phoenix CMR event at Watkins Glen, August '04.