C110: RB20 or L28?

[g72s20]

I think for your situation Alpha, keep your eyes open for a fresh L28. I have no idea what the performance potential is of the NAPS, was this a change for emissions sake? Or can it actually be made to get the L6 to lift its skirts and run? As you say, triple Webers will always be expensive. There is a lot of potential in the twin su/hitachi's evidenced by the various class racing that demand these on the Z's. Maybe put some dollars into the set you have for a warm 2.8? If you are budget concious (and who isn't?) you don't want to build too much horsepower into your car because you have to be able to reign it in and control it as well ....bigger brakes, better suspension, the rest of the drive train from the clutch back. How much can the original bits take? All adds up to lotsa money.

A nice clean L28 with fresh carbies or tricked up injection (anybody know anything of the performance potential of the NAPS?)...extractors into a twin system purely for the sound to match the looks! A mild cam...I reckon this would keep you happy without breaking the bank so you could keep the car long enough that in time your new job will be able to finance that engine change (and all the other mods this would demand) of the future to whatever your heart desires!

Personally,eventually I want to see a twincam crossflow NA six with "adequate" power in my KGC10. It's a way off yet so I guess in the mean time I'm doing just what you are, seeing what's out there and just what it's going to take to get what I want.

below is my idea of "adequate" 237PS S20 care of Shiraishi Engineering Japan.

[Mat Big Hat]

The RB-S30 swap is increasing in popularity. It's newer technology and looks pretty cool as well. Many of these z-hybrids are purpose built street/drag cars. The extra weight affects road course and autocross handling, but has less of an effect on a straight-line car.

An RB-KGC swap would be a good choice because the Kenmeri is rarely a purpose built track car, rather a GT cruiser. The twin-cam cylinder head hearkens back to the original "R" spec models without the fuss and cost of an S20. The modern induction is functional and efficient, but triple sidedraughts would blend an interesting combination of old and new technology, even more of an homage to the S20 R spec, especially if combined with extractors.

The SR-S30 seems to be better suited for track use for obvious reasons, so it'll be interesting to see how much of an improvement the SR swap is to the handling of the KGC.

One thing that hasn't been mentioned is a Cedric/Q45 V8 swap. Plenty of room under the bonnet of either the S30 or KGC, lots of grunt and growl, potentially better weight distribution, and still a Nissan product for the purists.

[Mr Camouflage]

The NAPS (Nissan Anti-Polution System) intake manifold has a twin throtle valve, One main one, and one slightly smaller than the other. The Plenum is larger than the other efi manifolds, and the runners are about the same diameter.

NZedder will be able to tell us more, as he has one.

I think you have to replace the throttle body with a single valve throttle body for better performance.

[Cuong Nguyen]

[quote name= RB25 head on RB30 block would be a good swap but your loosing economy then.

not sure how much truth there is in that! i would have thought that with a more modern cylinder head that the chances of getting better economy would increase if the tuning is spot on.

of course economy goes out the window if the right foot is heavy on the pedal...

personally i wouldnt bother doing the whole RB conversion for the RB20 as they do not have much torque, lots of work for not much gain. unless you are prepared to go RB25DET or bigger then stick with L28.

[240K&Beyond]

Hi Lachlin,

Knowing budget contraints, I would go down the "bulit it up" slowly path. Myself, always the L28, unless I had a spare RB26 lying around, and who does?

My old K coupe had a L28...R motor in it which I bolted a T3 hair dryer to with an extra 80Hp injector system. Running 6 PSI, two head gaskets and no intercooler, I was puting out 350HP at the rear wheels. No matter what I did to the diff and suspension, I couldn't stop the back wheels from spinning in any gear (including 5th) There was nothing better than crusing around at 80 to 100 kms and dropping them hammer next to another car, bagging the rears and taking off with two trails of smoke. Chasing any more power would be life threatening !

But back to the subject at hand, I have checked with Vicroads and the NSW RTA both say that you can drop a L24/26/28 Cary or EFI into a K without an engineer's certificate. Making things too easy. I assume the QLD RTA would say the same.

I have chosen to keep the "Old School" approach with the L28EFI. Although I am planing a toyota supercharge, T3 turbo charger hybrid later down the track. Built for torque and quick response. You get the car registered quickly and easily with the L28 engine number and insurance companies can see the car without "hitting the roof". Then build it up later and the engine number still matches all records.

Personally Mate, look for a 1983 280ZX manual car. They have the F54 strengthened Block and the P90 Head with larger valves. And a manual EFI system which will wire into your car with only six connections. (I have the EFI docco if you need it) I bought one off ebay registered for $1100 AUS a year and a bit ago. Stripped what I needed and dumped the rest.

This would give you an good starting point to which you could decide where you want to go: Further EFI work, Turbos, Superchargers, Triple carbys - whatever.

And at the end of the day, when you lift the bonnet of your old school skyline, you don't have a face full of techno. Just something that looks original, however tricked it may be.

This is my preference and opinion - I don't mean any offense to others.

Keeping it Simple ;-)

[blue_leaf]

My old K coupe had a L28...R motor in it

Whats an L28R motor? or is it just a typo?

Running 6 PSI, two head gaskets and no intercooler, I was puting out 350HP at the rear wheels.

Anyway 350 Hp on 6 psi and with no intercooler?!!! wow, thats a great achievement! Give us more specs -turbo specs, head, intake/exhaust manifold did you use? What sort of compression did you get by using twin gaskets?

Also what car used P90 in Australia? I was under the impression that they were never put on Aussie cars. Do you have a P90 that you might wish to part with?

[aarc240]

What sort of compression did you get by using twin gaskets?

Pretty close to 7.6:1

[aarc240]

The NAPS (Nissan Anti-Pollution System) intake manifold has a twin throttle valve, One main one, and one slightly smaller than the other. The Plenum is larger than the other Edi manifolds, and the runners are about the same diameter.

NZedder will be able to tell us more, as he has one.

I think you have to replace the throttle body with a single valve throttle body for better performance.

The plenum might be bigger but the flow bench shows uneven airflow distribution to the cylinders when fitted with a single plate throttle body.

I've got one of those things too and it is a pollution 'fix' not a performance device.

Like NZedder I'm going with a modern ECU. I think his plan is a MegaSquirt, mine is a MicroSquirt (very little difference, conventional components vs SMD). Don't know what ignition NZedder plans, mine will be crank triggered Ford EDIS.

Single plate throttle body is so that a Throttle Position Sensor will give sane output throughout the movement range, nothing to do with performance.

I've now junked the NAPS and switched to a 'normal' 280zx single plate throttle body injection rig.

[aarc240]

For anyone keen enough:

http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=4646772918&ssPageName=ADME:B:SS:AU:1

BUT there are no injectors, fuel pressure regulator and a few other bits you will need.

btw, injectors on a 280zx (OZ release) and an RB30 (VL Commodore or R31 Skyline) are the same parts!

[Mr Camouflage]

There were a naps manifolds on ebay.au and ebay.com about 1 or 2 months ago. The one in Aus was listed at $75 and had the fuel rail and injectors, the usa one didnt and was listed at $300.

I've been told to use the non egr N42 intake manifold for efi + turbo from someone that has the same setup.

[aarc240]

Not sure where you'll get a non-EGR manifold in OZ - we didn't get EFI until after July 1976 when EGR became a mandated requirement under the ADRs.

Apparently these non-EGR manifolds appeared on '75 280Z US models.

Not a problem, just cut the EGR extension off the manifold and have a plug TIG or MIG welded in. A quick buff over with an 80 grit disk smooths it out and if you are fussy, a 320 grit disk will get it neat.

There's no reason you couldn't have the EGR valve there and mounted with a stainless steel plate under it - be pretty hard to get EGR working then!

btw, the NAPS manifolds I have looked at have nearly all been L20E import or L24E (R30?) units and the injectors are NOT adequate for an L28.

[NZeder]

I no longer have my NAPS manifold - but as others have stated the plenium is larger and the twin butterfly thing. My NAPS manifold came from a L28 - I have not seen a NAPS on a L20aE yet (which means I have not looked hard enough). Re the quesiton about my ignition plans - I have 6 L20ET/L28E CAS dizzies (Yes the later L28E fitted to 280zx JDM have CAS systems - my NAPS engine has one but the dizzy is empty just a rotor as the CAS is a pick mounted to the block with a toothed wheel behind the front pully/balancer all Nissan kit) so I plan to use this setup to begin with. I am going with EFI Hardware Triple Throttle Bodies (from Speedtech in VIC I believe) for a bit of the old school look but with modern tech + I love the sounds triples make and I have not seen too many setup's like this here in NZ on a Zed (I know there are of 1 race car L6 engines getting built but this will have 50mm triple TB and be one hell of a 3.1 stroker going into a HS130/280zx 2 seater)

I do like the idea of a RB with triple's be it carbs of TBs. Here in NZ like OZ there are lots of VL's RB30 around and they can be picked up from nil to a few hundred dollars. However I personally would not put this into a S30 - however we are not talking about a S30 now are we as Lachlan has a C110 which has a different body/weight layout so the extra weight in a RB might not be an issue. Whatever you decide Lachlan I would love to see it say a in-line 6. Given how your cars looks externally don't do a SR20 or V8 (again this is just my opinion) it will spoil all the good work in making a GTR rep on the outside. If you want a SR20 or V8 conversion get a 510 for SR20 conversion and a C330 for the V8 (I thing a Nissan V8 in a 260C would be very cool but to be the badest 260c with a V8 it would have to be the 2 door hardtop version )

Cheers

Mike