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: NA & TT differences and conversion facts.
: Russell Floyd ZX Connection (Exclusively Z32)
: Used parts, Aftermarket parts, service, performance, sales.
: zxparts@mindspring.com 770-562-8668
: I have gathered this info over the past couple years. I have tons of TT and NA parts to compare and a Nissan Computer system at my disposal, so I am not including any info that is questionable. ENGINE
: 1. The blocks are the same casting. They both have oil squirters that direct oil towards the underside of the piston, although they point at slightly different angles. They have all of the same oil passages. Two passages are plugged with a bolt on the NA block (one on each outside face that feed the turbos on a TT). The TT has two oil passages plugged inside where the oil filter bracket mounts. The NA has two small check valves in this location. They are plugged in the TT so that the oil will go through the lines to the oil cooler, which returns back to the oil pan. The NA block can be used in a TT just by removing the plugs for the turbo lines and plugging the bypass holes under the oil filter bracket.
: 2. The crankshaft is the same.
: 3. Connecting rods ARE the same!! (Same Nissan part #)
: 4. Piston rings, and crankshaft (main) bearings are the same. The rod bearings are the same size but the TT ones are made from a different alloy.
: 5. Of course the pistons are different because of lower compression ratio in the TT. Oil pumps are different. They mount the same but the TT one is higher output.
: 6. Oil filter bracket on a TT is different it has an outlet that accommodates the hose going to the oil cooler.
: 7. Cams, Lifters, and valve springs ARE the same (90-93)(same Nissan Part #). The automatic TT has different intake cams (lower lift) but the intake cams on the 5 speed TT, NA, and auto NA are the same. All the exhaust cams are the same. The 94-95 cams were different than the 90-93 but just like the earlier ones they are all the same except for the intake cams on the auto TT. In 96 cams were all the same.
: 8. The valves are all the same size. But the exhaust valves on a TT are made from a stronger alloy.
: 9. The bare heads are different. They are slightly thicker on the TT as seen by the longer spark plug. This provides added strength for boost, but you could probably get by with NA heads under normal boost conditions.
: 10. The oil pan is different because the TT one has 2 tubes protruding on the sides where the oil return hoses for the turbos mount and another one for the hose returning from the oil cooler.
: The oil cooler is only on TT?s and mounts in front of the radiator and AC condensor. If converting you might want to go with an upgraded one.
: 11.The turbo engine obviously has a few different accessories and systems to accommodate the turbos. The exhaust manifolds on the TT go right from the head to the turbo, shorter path than the than the NA ones, which run all the way down to the main catalytic converter sections. The turbos are oil lubricated and water cooled. So there are oil and water feed and return lines.
: There is a network of vacuum lines and solenoids to control the wastegates for the turbos, controlling boost. If doing a conversion I recommend a boost controller, which will allow you to eliminate almost all of that stuff, and keeps you from having to worry about safety boost problems.
: 12. The throttle bodies are the same size but the passenger side one is different on a TT simply because one of the water lines attached to the bottom of it has a junction to feed water to one turbo.
The upper and lower intake manifolds are the same TT and NA although the 94 up ones are different from the earlier ones.
: ELECTRICAL
: 1. Nissan claimed the TT coil packs were different a couple years ago and charged a lot more for them. I checked them and found that they were the same and now Nissan lists them as the same.
: 2. Of course the ECU is different.
: 3. The Main engine harness is different also, but a NA harness will work in an TT, you just wont have the connections for the boost control solenoids which you don?t need anyway if you have a boost controller.
: 4. If converting NA --> TT, I would leave the interior harness and gauge cluster alone. They will work with the TT setup. Get a stand alone boost gauge because the stock one sux. You probably wouldn't add the Hicas system or stock electronic adjustable suspension to a NA so you will not need the TT interior harness.
: 5. MAF, PTU, TPS, IAA, AIV, EGR, O2 sensors, Detonation sensor, Coolant temperature sensor are all the same.
: 6. The electrical AC Condenser fan is different on a TT. The motor has three wires (2 speed) going to it as opposed to two (one speed) on the NA.
: 7. The starters are all the same
OTHER DRIVETRAIN
: 1. If converting most people would keep the NA rear differential, because a lot of TT owners switch to it anyway. It has a lower ratio (4.08 compared to 3.67) that will decrease your top speed but enhance take off. If you want to swap to the TT diff you have to swap the whole rear subframe and halfshafts. You have to do the same if installing an NA diff in a TT.
: 2. As long as you keep the NA rear diff, the NA driveshaft will work. The TT driveshaft will not work with an NA diff.
: 3. The NA and TT have the same 5 speed transmission model #, same splines on input and output shafts, etc. and the housings are the same except for one small difference. The spot where the starter mounts on the bellhousing on the TT is machined a little differently so that the starter will properly engage the slightly larger diameter flywheel and so that the flywheel teeth won?t scrape the inside of the bellhousing. You can use an NA 5 speed in a TT but you just have to shim the starter out a little with some flat washers and sometimes grind a little out of the inside of the bellhousing so the TT flywheel will fit inside.
: If trying to use a TT trans in an NA you would either have to grind down where the starter mounts so that it could engage the smaller NA flywheel or just use the TT flywheel and clutch.
: The automatic transmission is different for a TT, but the NA auto would still fit in place behind the TT engine, but probably wouldn?t last long. Although, they are different lengths and you would have to use the corresponding driveshaft. Both autos are geared virtually the same but the TT one is built for heavier duty.
: 4. The speed sensor in the transmission is also different, which has a different size gear for NA and TT because of the different ratios in the diff. But if you are using a NA diff you need a NA speed sensor.
: 5. The 5 speed TT clutch has a larger contact face, a stronger pressure plate and a slightly larger diameter flywheel. Because of the stiffer pressure plate, the TT has a clutch booster assembly operated from engine vacuum similar to the brake booster which the same on all Z?s. The clutch booster includes two plastic tanks for vacuum storage and the hoses running between them, one under the driver?s fender and one under the clutch master cylinder. The TT clutch pedal and clutch master cylinder are also different because of the booster assembly. You could use a TT clutch in an NA or a conversion without the booster but you would just have a stiff clutch pedal.
: OTHER STUFF
: 1. The Radiator and AC Condenser are MUCH different. They are much narrower on a TT so the intercooler piping can go around each side. The front lower core support is also different (but can be modified to work with a little cutting and welding) because the TT radiator and condenser mount farther down into it because they are taller to make up for the difference in width. There are some differences in the AC lines also.
: 1. You
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