SPE­CIAL BUILD

GRAEME SMYTH IS LOOK­ING TO ADD A LIT­TLE STRAIGHT-LINE SPEED TO HIS AL­READY QUICK 13B-POW­ERED FD RX-7, WHICH WE FEA­TURED ON THE COVER OF IS­SUE NO. 238, HAV­ING SOON FOUND THE LIMIT OF WHAT THE NAT­U­RALLY ASPIRATED 13B CAN ACHIEVE

NZ Performance Car - - Contents -

Last year saw Graeme break out of GTRNZ’s GT2 time lim­its — as he ex­plains: “I broke out of GT2 with the 13B NA [nat­u­rally aspirated]. I could run a lap time to win a race no wor­ries, but then, in a hand­i­cap race, I’d pass, say, a su­per tourer or what­ever through the mid­sec­tion, but it would just blast back past me on the straight, so try­ing to race was frus­trat­ing.” The an­swer was to add a lit­tle boost to the equa­tion. The chas­sis will stay as is, with the only changes com­ing in the form of the en­gine. The 13B bridge­port with X-Treme Ro­taries quad throt­tles is now up for sale, with a new Cur­ran Brothers Rac­ing (CBR) 13B based on an FD block ready to slot in the hole. The mo­tor will fea­ture bridge­ported plates and be dow­elled. An Xces­sive lower man­i­fold is mated to an FD top with fac­tory throt­tle body. Boost will come via a Pre­ci­sion 67/65 Gen II, and the waste­gate con­fig­u­ra­tion is yet to be de­cided.

Like the rest of the fab­ri­ca­tion, this is Graeme’s own hand­i­work. He will also make the in­take tanks for the in­ter­cooler. The clutch pack­age, Mo­dena six-speed se­quen­tial, and nine-inch in­de­pen­dent rear sus­pen­sion (IRS) diff — with new ra­tio — will re­main. A switch to E85 will see a new fuel sys­tem added, with a Ra­dium fuel cell with in­te­grated surge tank to be mounted in the rear. Power fig­ures will not be ex­ces­sive. “The way I look at it,” Graeme tells us, “we are only look­ing at around 550– 600hp [410–447kW], and it’s on a 280/680R18 slick. That is the same as V8 su­per­car, and they are sup­pos­edly mak­ing 500–600hp [373–447kW], so it should get good drive, and mid-cor­ner speed should be no slower than it is. I’d like to think it will go faster than a 29 [1min 29s] at Taupo and a three or four [1min 3s / 1min 4s] at Hamp­tons.” To en­sure that the well-han­dling FD suf­fers no side ef­fects from the added weight, weight will be re­moved else­where to counter, with the goal to re­main at the 1208kg with Graeme on board. Ex­pect to see the FD run­ning in GT1 and maybe do­ing some time at­tack later this year.

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