Gallery: Engine & Drivetrain

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 Hmmmm!—Anybody got a shoe horn? I did a lot of measuring on “showroom display LS7″ at local race shop & inside,underside of NSX before purchase. LS7 crate motor is Chevy’s most sophisticated ever! All aluminum, 427 cu. in., titanium rods & valves, 11:1 compression, dry-sump, 505 hp, 470 lbs. torque!—with a 1 year warranty!

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 This part # has been superceded—bought motor in 2006 (before they lowered redline in ECU)

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 Can you believe this 7 liter with Porsche 5 speed transaxle weighs 35 lbs LESS than stock NSX 3 liter engine & tranny?!

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 Decided to build “dummy” engine & tranny for late-night under-car measuring & fitting. Much easier when entire assy, weighs in around 15 lbs (instead of 550 lbs). Cut rigid urethane foam with kitchen knife, glued with contact cement, used a rasp to contour all surfaces to replicate exact dimensions of LS7 (in critical areas) & sealed with Urethane-based fiberglass resin.

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 What?–You don’t recognize a Porsche G50-50 transaxle when you see one?

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 “Dummy” in early stages of firewall cutting, & calculating rear crossmember design / clearances.

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Engine bay view from passenger side reveals wooden dowel sticking out of tranny “dummy” (represents axle centerline).Â

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 Determining just how far forward engine could be placed, & still clear main cross-brace of Roll-cage (actually had to re-design cross-brace for “extra” clearance). This shot is very early in process—later, significantly more firewall was removed so engine could position even farther forward—which not only helps weight distribution, but rear axle alignment issues with transaxle.

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 Originally intended to keep trunk, & simply fab a cover for transaxle where it encroached—but later on decided to scrap entire rear body section (see pics in “chassis” gallery) in favor of a “racier”, & more aero configuration (don’t play golf anyway).

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 Rear view of underside during early phase of determining engine & tranny placement, including relative height in chassis. Since the Porsche transaxle has to be mounted inverted (to accomodate mid-engine installation), & because LS7 is Dry-Sump, entire assy is mounted MUCH lower than stock NSX engine—which is notoriously high anyway because of “compromise” lateral transaxle & engine position!

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 There’s just something special about unwrapping REAL horsepower!

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 Rear end of car has to be jacked VERY high off the ground, so engine & tranny assy can be installed from underneath (note mover’s dolly nested between the frame of the cherry-picker). The biggest challenge at this stage was clearing the inside edges of newly-cut OEM NSX rear suspension castings—can you believe about a 1/4″ total clearance (at tightest point)?

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LS 7 trial install (note foam core firewall at this stage).

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Chrome-moly engine crossmember ties into lower main bar of roll-cage (where it passes thru tunnel), & serves to triangulate the rear frame rails to the cage / tub structure. Â (Notice it is designed to be just in front of, & slightly lower than LS7 cast pan—for protection from “high-centering’ events). Bottom plane of crossmember is aligned with bottom plane of NSX frame rails, as well as bottom of rear transaxle support crossmember (visible at left edge of pic). This assures a nice aero package later on when CF belly pan is fabbed to blend into rear diffuser. You can see the OEM suspension casting has been moved 2″ aft (top-center of pic–full discussion of this in “chassis” gallery).

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Early phase of determining final height of transaxle, designing mount to attach tranny to newly-fabbed rear crossmember, & checking axle centerline with relationship to axle “stubs” on Porsche box. Note the cool side shift conversion mfg. by California Motorsports (on left side of Porsche G50-50)!

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Nice view of engine-bay layout—custom firewall w/raised center to accomodate Harrop (Eaton) supercharger & CF plenum that seals-up to rear lexan window. Shock-bridge detail reveals structurally-rigid design, while still remaining light-weight! Triangulation of lower CM sub-frame & “K-member” is evident. Note all of the chassis layout info & centerlines on garage floor—who needs a surface plate!

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Different view shows the twin 3″ aluminum fuel-fill tubes that are welded to firewall (& inside of cabin) for extra torsional rigidity. Photo reveals copius amounts of triangulation—can you spell “STIFF”?

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Just above the raised center of the firewall, a triangle-shaped aluminum plate (with 4″ hole in ctr.) ties the entire bulkhead to the upper rear roof structure—it also serves as a central attachment point for what will be a fireproof & bulletproof window (thank NASA) between driver’s cabin & engine compartment. It’s a special polycarbonate used mostly in military applications. Notice all of the room for custom header routing! They will be high in the bay, due to “aero-tunnels” built into the CF belly pan.

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L.R frame rail shot reveals relative placement of the upper control arm attachment points to the lower ones. The geometry is Z06, but not the dimensions. The aluminum dowel in bottom pick-ups is simply used to align the 2 in the same plane, as each pick-up is serrated on the back, & can be adjusted up or down a total of 1.5″

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View of engine-support crossmember (from driver’s-side, looking rearward).

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Engine support crossmember as viewed from bottom center, looking rearward. Note how it bolts into the lower main bar of the roll cage (where it intersects the tunnel). This is designed to help keep the engine from invading driver’s compartment in critical front impact!

Pankl Axle & Inboard drive-hub

Trick gun-drilled Pankl axle is 300m material, tripods are bulletproof! Dark grey drive hub is made by Hewland—the one on the axle is for an XTRAC box—have to custom-fab a pair for the Porsche box (ouch)!

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