Z432 Tribute Opinions

[dwarlick]

Hey! I haven't been around much since I sold my RB26 240z. I bought a Porsche 996 Turbo and had fun with that this summer. I want to get my hands dirty and am thinking about doing another RBZ. It would be a Z432 tribute with an RB20 with Triple Carbs. This has been mentioned in passing on Hybrid Z before but never attempted to my knowledge. I would like to make it a high revving motor so a bottom end rebuild would be needed plus the switch from Turbo to N/A would require higher compression pistons. I'd like to keep the budget under $10k. Assuming I start with a clean body and paint would this be a saleable project or would it be too quirky to appeal to a broader market. My RB26 was a bit of a kick in the balls when I went to sell it but I was really at a dead end. Would a more modest project like a Z432 be at least breakeven because of the lower price point or would I be doing a project that only interests me and plan to lose $5-10k? A lot to mull over but any input would be appreciated.

[djz]

No reason to start with a turbo motor, N/A RB20s are probably more common. To be honest it would be a lot of work (and expense) for very little power though, apart from the RB having 1 extra cam you'd be better off with an L28.

[R3VO 3VOM]

The RB carb thing has been done before with rock auto and their "carbon" Z on an 26/30 hybrid. Im not really sure how they did the ECU/ignition stuff though since they ditched some of the sensors. Cool concept but im not sure the cost is justified. I have a 20 with 26 itb's in my z and the preliminary costs seem cheap but then the parts prices just start piling up. The adapter/spacer flange alone wouldve cost $1,000 if i didnt work at a place i can get metal.

Edited November 29, 2012 by R3VO 3VOM

[ZT-R]

Well Im glad to see your still around. I miss seeing your rbz. I dont really have much input about this subject but the L series would seem more level headed, but not as rare. But then again sellability...

[dwarlick]

A L28 would be a better way to go but then you don't have the "2" liter part of the 432 plus other than badging and fender mirrors its a normal 240z.

 

A N/A RB20 would be an better start except that the only RB20s getting imported to the US are turbos and since the shipping is a killer it would be cheaper to get a DET motorset for $1,500USD

Edited November 29, 2012 by dwarlick

[R3VO 3VOM]

I was thinking about this today. It woulnd't be "that" hard. The real factor would be how cheap you could get the carbs for and how much fabrication do you want to do. Tripples aren't cheap in any sense.

 

You could get a motorset like this: http://www.ebay.com/...1dd8ffd&vxp=mtr

 

For the intake, you could do something like I was going to do before I realized the holes on my 26 intake lined up.

Take the stock lower intake and cut it down (the runners would probably have to be shorter since runner 1 kicks up higher at the length I have them than the rest), get some flanges made that match the carbs and bolt them on. this way you keep the coolant sensors. You'd need the plug the fuel injector holes and figure out a throttle linkage. The other problem would be the spacing of the runners and the spacing on the carbs; if the runners will line up with the carbs or not.

[dwarlick]

That looks similar to the approach rocky auto took on carbon z you mentioned. In one of the pictures you can see the injector hole so they just adapted the carbs using the stock intake. Nice find on the motor I didn't see any N/A motors when I searched. Now if I only had one of the three rear sump pans and pickups I had from my old Z. Thanks for the input. Keeping it simple is the way to go. That was another reason for doing the carb'ed motor would be no major modifications to the fuel system would be needed. I am well aware of the bits and pieces adding up on the RB swap.

[ZT-R]

i have one of pats first pans if you need it. I ran a mckinney aluminum one.

[stony]

Would a NA hi compression RB26 with nitrous be able to produce the same HP (or close) to a turbo car? I have always like the look of the rb series converted to NA with triple carb setup.

[dwarlick]

I'm not sure you would think as with most N/A Nissans it would have a hell of a lot of torque. It might flatten out at the top end on HP. Unfortunately the Rocky Auto guys haven't published any dyno results on their carb'd Z's.

 

Things are kind of falling in place on the preliminary investigating into this build. I don't think I can resist. I am going to try to start a build thread this time. I should have done one on the last RBZ I did.

[R3VO 3VOM]

If I remember correctly the magazine I saw the carbon z in said it had around 300hp. Nothing crazy, but it was coming from a 26/30. 30's have that extra liter of displacement; ive never driven a 30, but i hear they are quite torquey.

Im sure you could boost it up as with any n/a engine. High comp pistons, big jet carbs and stuff like that. Just do you need it is the question.

[dwarlick]

I was trying to figure out a custom distributor setup off the CAS housing but I think it would be too complicated. If the factory ECU was only hooked to the ignitor and the CAS would it provide the spark I need or would it be affected by the limp mode?

[R3VO 3VOM]

I couldn't say for certain. You might need to contact Carl H. He tunes RB ECU's and is all over a lot of forums; he could probably answer this question no problem. I would say if I were to do this, I'd try to keep all the sensors (minus like idle air bypass and stuff like that with a jumper across the points maybe?) so that the ECU doesn't read an open circuit or a non-existent sensor.

[NZeder]

I am going to be running a RB on triple carbs...when I get a round to working the car again. With regards to the timing I have a few options/ideas that I will work on.

 

1 a dizzy setup. For this I plan to get a RB30e dizzy and strip that and see if I can mate that with the cas.

 

2. Use the electromotive xdi crank trigger wasted spark.

 

3. Use a microsquirt with crank trigger and 3 external coil drivers in wasted spark mode. This does also give the option of going to efi via batch injection.

Edited December 7, 2012 by NZeder

[Tony D]

Uh, just to set the record straight, the "2" stood for 2 Overhead Cams, not 2-Litre!

 

4 Valves Per Cylinder

3 Carburettors

2 Overhead Camshafts

 

Unless you got an OSG TC24B/Z-1 on that L-Engine (or a home built permutation/conversion) THAT would "blow the 2-Thing"...

 

Although "Z231" might appeal to some...

[Xnke]

So do the work to bolt down the RB20e head onto the L block, run an L dizzy and triple mikunies, and custom cast an upper front timing cover and valve cover...call it an LY28 tribute...

 

(Yes, I know who makes those castings and I wish I could afford to buy them!)

[R3VO 3VOM]

Although the 2 didnt stand for 2 liter wasnt the engine of the 432 a 2 liter? Wasnt it the s20?

[kiwi303]

yes, it was the S20, same as some early Skylines, but the "2" doesn't actually stand for the capacity, but the cams.

[dwarlick]

I had heard both versions of the "2" but tony is correct. I do think the 2.0 would be appropriate for this build.
As for the timing Matt at mega squirt said the CAS will work with the AEM wheel. He thought a crank trigger would be easier though. Since I did the trigger wheel swap before and know it only took about 10 min. I will try that first. I'd rather not clutter up the front with a crank sensor. The other nice thing is I can use the MS 1 which has an internal igniter they also sell a six post coil pack which should be nice and tidy. The whole lot is less than 500 bucks.

I have already bought an RB20det motor and tranny local for super cheep. If nothing else I'll use it to do the mock up for the intake and exhaust and get a DE later. I spoke to ARias and they can make some flat top pistons with the stock 10.2-1 de compression. Does anyone know if the bottom end is stronger on the det than the de? One would think it would be because of the added horseys.  I would also need to figure out the cams.  Since i got the motor so cheep would it be better at this point to rework the RB20 or get a DE shipped to me for about $1k?  And which would have the higher rev potential?

 

The mikunis are en route. 

Edited December 8, 2012 by dwarlick

[R3VO 3VOM]

Yeah. I knew it was 2 cams. But I was just thinking that it happened to also be a 2 liter.

 

I think the bottom ends are the same to my knowledge. I havent looked too much into the RB20DE's (theres not nearly as much out there for them easily available like there is for the DET's). But if you got it for super cheap, I'd say just swap out the pistons and go from there; people push 400+hp through the stock bottomends (I've seen 500 but that was for pure dyno and drag runs; longevity im sure was in question) so I think the stock bottom should hold up. We have to remember about the cost aspect referenced in the first post. Unless you have another car to put the 20 in after you got finished with the mock up, I'd say run with it.

The question is though are the heads different? I know that on the SR20, the cc in the heads are different sizes between the DE and DET. But like I said, there isnt a whole lot out there on the RB20DE unless you really look. More is out there for the RB25DE, but still isnt a lot.

 

Depending on your cost now, you can either get some custom cams done or source some red top cams. I know that they are a "hotter" profile than the stock silver top cams, but again, this is in the turbo variation. I'm unsure of the profile on the DE cams.