Author Topic: FWD U12 and U13 Differences  (Read 1280 times)

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Offline Leopard-Man

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FWD U12 and U13 Differences
« on: Jun 15, 2005, 08:13PM »
Hey, 
     This is in the U12 tech section.  I just thought id put it here as well so some of the U13 members dont miss it.  Originally posted By RichTRX but i helped with information so its all good.   Enjoy  ;D

Engine/drivetrain
The one's obvious - the u13 uses the twin cam KA24DE with 112kw and the u12 uses the single cam KA24E with 96kw. Standing accelleration (from tests results) is dramatically improved from 8.9sec (u12 man) to 7.9sec (u13 man) however the main difference between the two (from my experience) is the u13's very strong mid-range (which is where is leaves the u12). As described in the suspension section, the engine crossmember (which is the same as the u12's) is bolted onto a subframe along with the front suspension, which is then bolted along with large rubber bushings, to the body, greatly decreasing vibration from the engine and road. Other differences to the u13's engine include different injectors which are integrated with the fuel rail, different plenum setup (utilising an updraught instead of the KA24E's downdraught), different gearbox mount, different front mount (much better support than that in the u12 - I believe it will fit the u12 with no problems as well), different left mount (which also includes a balance weight). The rear mount appears the same as in the u12. The coil is also a more compact design. The KA24DE also uses two timing chains. The lower chain is a single row setup similar to (if not the same as) the KA24E, and drives off the crank to a 3 row gear at the bottom of the head. This then drives a 2 row chain which runs both camshafts.

The clutch master cylinder, slave cylinder and clutch unit itself all appear to be the same as what is used in the u12.

The transaxle is the same LSD unit as in the U12 Ti and TRX. It mounts to the body via a different mount as mentioned earlier, but is otherwise exactly the same. Driveshafts may be slightly longer in the u13 to make up for the extra body wideness but I'm not 100% on this point, and the CV joints are the same size but I believe a number of u13's came out with 1 less spline on their driveshafts... not sure why. They both use the same inner and outer boots however, as well as using the same support bearing on the driver's side.

Exhaust is dealt with using a cast iron header (as in the u12), shorter flex pipe than the u12 and also a larger catalytic converter. The resonator and muffler are the same, except the muffler in the u13 has a Nissan logo embossed on it.

Steering
The u13 looks to use the same p/s pump as the u12, although power steering is standard fitment on the u13. The steering rack is slightly different though, allowing for more travel than the u12. It also has air balance pipes built into the rack itself, rather than being built into the boot as in the u12's rack. This means that the balance pipe can't come off and allow dust/water/etc. into the rack. The boots are also substantially bigger to allow for the extra steering travel. The inner ball joint appears to be adjustable (the u12's isnt), although I'm not 100% on this. The tie rod ends are also different, being substantally longer than the u12's. The thread, castellated nuts and split pins however are exactly the same. The cooling pipes on the front of the car also seem to be quite similar to the u12's.

Suspension
The front and rear suspension setups are essentially the same as the u12 (and use many of the same parts) except for the following points:

1) u13 front springs/struts are at least 50% wider diameter than u12 providing extra stiffness. Rear springs are same as u12.
2) u13 front sway bar, instead of running under the body as in the u12, runs along the firewall just under the steering rack
3) u13 rear sway bar uses integrated ball joints as pivot points instead of the u12's link rubber arrangement
4) u13 rear parallel links are unequal length (presumably to provide better toe out/toe in while cornering hard) compared to the u12's equal length links
5) the u13 rear end has adjustable camber (to a degree anyway) with a separate hub assembly (compared to the u12's integrated hub/strut with no camber adjustment)
6) both the front and rear suspension units on the u13 (except for the strut tower bolts) are bolted to a front and rear subframe which are in turn bolted onto the body with large rubber bushings. This is probably the most important difference and is quite a leap forward from the u12 (in which both suspension setups are bolted to the body)
7) u13 uses a much shorter rear radius rod than the u12 (like 1/2 as short).

Seats
The main difference in the front seats is that the driver's seat in the u13 has angle adjustment (you can adjust the angle of the seat cushion).
The rear seat (in the LX Bluebird) is not a split/fold seat and cannot be folded down as in the u12. The seat cushion is also bolt in (not clip in like the u12). The back cushion is only 1 piece, where the u12 is 4 piece (bolster-60split-40split-bolster).

Hub and Brakes
The u13 hub and brake setup seems to be quite similar to the u12 with the following points being some of the differeces:
1) u13 brakes are quite a lot bigger than the u12, both the front and rear. They both still only use single piston calipers but are still quite a lot bigger. Discs are still full floating type.
2) the rear hub in the u13 is a seperate unit. The u12's is built onto the strut.
3) I don't know for sure but I believe the u13 has a different number of splines in the hub/driveshaft link up than the u12.
4) brake booster/master cylinder appears to be the same as in the u12 however it uses a different reservior which is less prone to becoming brittle like the u12's.
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Offline Budgie

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Re: FWD U12 and U13 Differences
« Reply #1 on: Apr 19, 2006, 01:27PM »
Zander, would entire U13 front struts bolt upto a U12... and vice-versa?

I ask, as I'm hoping to fit U13 D2 coilovers to my car.
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