Happy Birthday to me (280z build)

[walterclark]

I thought there was some rule prohibiting certain engine swaps in SP...e.g. not allowing a Mazda or Chevy swap into a Nissan, but I cant find one, only a statement about how cars with engine swaps would be classed to where they are competitive.

I would say the classification approach would begin by using the advertised 280Z curb weight, require the excessive lightening penalty, and the displacement of the 13B times the rotary multiplier to get effective displacement (something like 2119cc). Then add wheel/tire, suspension, intake, exhaust, turbo, intercooler and so on as appropriate, and the cage credit to get to the performance number and the class. The result might end up being adjusted by the classification committee because the listed curb weight is north of 2800 pounds which includes the weight of the original 2.8 liter 6. The excessive lightening penalty, by itself might not bring the calculated weight anywhere near the actual with the amount of body lightening and lighter engine combined this car could end up with.

From what I read the NA 13B can produce a bit over 200WHP depending on how it was set up and how well tuned.

[drummingpariah]

I thought there was some rule prohibiting certain engine swaps in SP...e.g. not allowing a Mazda or Chevy swap into a Nissan, but I cant find one, only a statement about how cars with engine swaps would be classed to where they are competitive.

I would say the classification approach would begin by using the advertised 280Z curb weight, require the excessive lightening penalty, and the displacement of the 13B times the rotary multiplier to get effective displacement (something like 2119cc). Then add wheel/tire, suspension, intake, exhaust, turbo, intercooler and so on as appropriate, and the cage credit to get to the performance number and the class. The result might end up being adjusted by the classification committee because the listed curb weight is north of 2800 pounds which includes the weight of the original 2.8 liter 6. The excessive lightening penalty, by itself might not bring the calculated weight anywhere near the actual with the amount of body lightening and lighter engine combined this car could end up with.

From what I read the NA 13B can produce a bit over 200WHP depending on how it was set up and how well tuned.

I'm pretty sure John and Dave are both right around 200whp in their FC's, so that shouldn't be a real issue. The porting required to make that kind of power destroys the concept of using this as a daily driver though, as MPG would almost certainly drop to single digits. A turbocharger gives me the same power (more, potentially) but without the massive MPG hit (because I don't need to port the irons for those power levels).

Assuming we're treating the Zcar line like the Golf line (where there were a few different chassis) and I can use other Zcars as a starting point for wheels (rather than starting from the 280z's original 14x5.5, which doesn't even have viable tire choices any more), I could start with something like the 300zx's 16x9 wheels, and just take a minor modifier to bump that up to 17x9. That gives me several real tire choices, but I have to imagine that's too wide for a lightweight, relatively low-power chassis.

The next assumption is that we'd modify the GVWR by the weight difference between the two engine/transmission combinations. Starting with 2850lbs, according to my door) and taking off a very generous 150lbs between the factory l28e/4speed and the new 13bt/5speed combination, that puts my GVWR at 2700lbs. I originally expected the weight savings to be substantial, but after weighing all the individual components I have for the 13b (and turbo manifold, which is hefty), the engine is only 126lbs lighter than the l28e. The 13b turboII transmission is 18lbs heavier than the factory Datsun 4speed. The total real-world difference comes out to 108lbs saved. My measurements of the disassembled 13b components was just on my bathroom scale, as compared to l28et weights taken from the hybridz community (they're kind of fanatical about collecting and logging facts, which is why I like them). There is certainly some tolerance between those measurements, so I'm just rounding up to be on the safe side.

As far as I can tell, the n/a 13b would end up in sp6 even if I use the 2700lb GVWR (which includes the hefty turbo manifold, intercooler, etc).
https://files.driven-daily.com/index.ph ... aT5hb0pCox

With the l28et, it's firmly planted in sp2
https://files.driven-daily.com/index.ph ... z1u44zThWM

Finally, the 13b turbo with intercooler ends up in SP4 after cage, all the custom suspension, and turbo/intercooler on it.
https://files.driven-daily.com/index.ph ... prVquruubp

I expect there to be a lot of suspension teething issues with all the changes I'm making. I'm going to have to break a few bad driving habits that I'm just picking up on while I go over my footage from the season too.

Project Update
I accomplished far less than I hoped to this week. Tonight, I need to build a chassis cradle (to bring the car up to Joey tomorrow morning). All I have is 1" square tube, so this won't be an effective chassis straightening jig, but it'll be enough to keep the car off the ground and hold it together for transport.

If there's any time left over after that, I'll pull the front suspension too. It'd be nice to be able to clean up all the suspension components that I'm keeping while the chassis gets its cage. The more I look at my timeframe, the more I'm thinking that I should just stick with 240sx rear suspension for 2016, and worry about making a cantilever setup for it later. I'd have to replace/brace the strut towers caps, but that's even less work than developing the pushrod mounting points.

I now have an l28et in the way of getting anything done.


Cleaning up the tail end became a little bit of an obsession too. I spent more time removing previous-owner-crap than I care to admit. At least it's back to metal now.

[sdwarf36]

I thought there was some rule prohibiting certain engine swaps in SP...e.g. not allowing a Mazda or Chevy swap into a Nissan, but I cant find one, only a statement about how cars with engine swaps would be classed to where they are competitive.

I would say the classification approach would begin by using the advertised 280Z curb weight, require the excessive lightening penalty, and the displacement of the 13B times the rotary multiplier to get effective displacement (something like 2119cc). Then add wheel/tire, suspension, intake, exhaust, turbo, intercooler and so on as appropriate, and the cage credit to get to the performance number and the class. The result might end up being adjusted by the classification committee because the listed curb weight is north of 2800 pounds which includes the weight of the original 2.8 liter 6. The excessive lightening penalty, by itself might not bring the calculated weight anywhere near the actual with the amount of body lightening and lighter engine combined this car could end up with.

From what I read the NA 13B can produce a bit over 200WHP depending on how it was set up and how well tuned.

Or just run P.

[Rabbit Farmer]

Regardless of the class... it will be nice to have more cool cars at the hill.

[britracer89]

Yes I agree more cool cars at the hills is better. So I'll preface with build it drive it have fun with it.

I ran the numbers on the spreadsheet and it clearly places the car in SP2. I only did this because of my dis-taste of Mr. Wankel .
It is based on your figure of 2850 gvw, 4 passengers, actual displacement of 2106cc (1300x1.62=2106), non-stock springs, non-stock roll bar, modified suspension, 6 point cage, excessive lightening, turbo and inter-cooler.

As a 2 passenger it falls into sp4.

I don't see any way possible to get into sp6.

Doesn't really matter to me personally. I've run pretty much p3 for like 20 years in a British Spitoon (as John Reed once called it).

[walterclark]

I believe the standard 280Z as 2 passengers. There was a 2+2 variant available that added 2 "jump" seats in the rear. Not sure what if any chassis/body changes were made to do this that would set it apart from the non-2+2.

Without the turbo I would not be surprised to see it in SP4 or SP6, but not with a turbo and IC.

[britracer89]

If you add the non-stock induction and non-stock manifold due to motor swap then it is sp2 as 2 passenger.

[drummingpariah]

I believe the standard 280Z as 2 passengers. There was a 2+2 variant available that added 2 "jump" seats in the rear. Not sure what if any chassis/body changes were made to do this that would set it apart from the non-2+2.

Without the turbo I would not be surprised to see it in SP4 or SP6, but not with a turbo and IC.

That's how I had calculated it too, the na 13b puts it in SP5 or SP6, depending upon how seriously it's prepared. I haven't ever owned a 2+2, since their roofline kind of ruins the car for me.


vs

If you add the non-stock induction and non-stock manifold due to motor swap then it is sp2 as 2 passenger.

That brings up an interesting point. I had assumed the induction and manifold would be 'stock' if they match the engine, not if they match the chassis. It's technically still 'oem' so I could argue that point, either way I suppose.

The car saw some sun today, for a little while.


Dave came up, we built a small caster frame, tossed it into his trailer, and took it out to Vermont with Joey Kale. I hope to get it back sometime before the holidays, with a sizeable chunk of my budget for 2016 missing.

[Rabbit Farmer]

Next time you're at Joey's, give us a shout here. We can stop by....

[drummingpariah]

Next time you're at Joey's, give us a shout here. We can stop by....

Chris dropped in while we were up there, but I didn't have service and we were on a tight-ish timeframe (which is why we didn't get to the banquet). I'm hoping to get back up later this month, or early December, but I'll keep you in the loop.