78 280z RoadKill Rotsun 2.0

[rajien2]

Guys,

 

Well I jumped on to the bandwagon.... I picked up a 1978 280z last week, story I was told it had not ran for 7 years and was parked in a shed. Over all the car looks good very little rust and few dents, I am very happy. Took about 4 days thanks to work to get her running... At the end it needed a new fuel pump and a new clutch master and slave. It took a bit of welding to extend the new clutch master enough to fully depress the clutch but it worked! I drove it to a meeting at work today and back home without any issues. 

 

Slight issues:

- Only a speedo no other gauges (Need to pull the dash and look at the wiring)

- No brake lights or turn signals. (again wiring)

- Injector 1 is not activating thus only running on 5 pistons (Injector ordered)

- Rehose the fuel rail.

- Brake master is shot (Have a new one just need time to install)

 

Now the goals! Below the pictures.

 

 

 

 

I had been meaning to pick up a Z after watching Road Kill https://www.youtube.com/watch?v=WcjC00J8FaM

 

This was about a month ago, I just fell in love with the way the car looked. I have a new 2015 VW Jetta that I don't get to work on so I needed a project. Ideally I would want this car to be just like the Rotsun but done nicer, I really liked the turbo diesel sound. Now they really did not go into very much detail on how they did some of the things to the Rotsun, I have been browsing around looking for someone else who has attempted this but without any luck.

 

So from my research it has:

 

-V6 and tranny out of a S10 truck

-Rear Diff from a WRX 

-Turbo from a Turbo diesel 

 

Now my question is why not use a 350 v8? I have found plenty of information on a 350 swap into a 280z and it looks like its very straight forward, just a weekend if you have all the parts and kits. However I am having issues finding info about putting a turbo on a 350, looking at pictures there should be enough room in the engine bay. From my research I have found information on putting a turbo on a carb using a blow through carb from demon. Now this process looks simple, I dont think you need an ecu to manage anything because the carb is adding more fuel based on boost; is this true?

 

Now the questions based on route...

 

V8:

- Would a diff from a WRX hold up to the load of a v8 with a turbo?

- The little info I could find has a lot of 350's with twin turbo set ups, why is this can they run single? Could you fit 2 Turbos in with a v8 anyways?

 

V6:

- Would a v8 swap kit fit this V6 engine or is the engine mounts completely different?

- Could the stock fuel pump supply a v6 or upgrade?

- Does the WRX diff just bolt in? Looking at the video I looks like it, how about the shafts that go from the wheels to the diff? 

 

Over all I am looking for some feedback on the pros and cons of each set up.

 

Thanks for your help

[Team Zleep]

That Z looks too clean to roadkill... 

 

Want to trade shells? lol. 

[RebekahsZ]

The Roadkill Datsun was a total

POS-don't use it as a model for your car. Just lurk around this site and you will find a car to model yours after.

[1969honda]

First off welcome to the club, as for the V6  I'd be surprised if a v8 kit didn't fit the 4.3L as it is basically a 350 with two cylinders cut off, IIRC it is the same bore and stroke.  I had a couple different S-series trucks years ago with 4.3l, they had great torque but poor fuel economy, a SBC would gain more power and not much more weight with the same amount of work and a lot wider variety of performance upgrades down the road.  

 

As for the turbo options, look thru the v8 section on here and I'm sure you'll find plenty of information and people willing to help out.  Don't forget to do you homework and use the search function though, it'll save you a lot of time, flaming and hassel from those "in the know" that have answered similar questions multiple times. Good luck with the project!

[wayverippah]

If its a 77, you shouldn't need to swap out the diff (it should have an R200 in it). The weak point will be the half shafts and stub axles.

 

A 350 will fit no problem. Not sure if the mounts will work, but GM has always been good about making their parts interchangeable. You'll need engine or boost management of some sort if you're going to turbo though (even with a carb). There is info in the v8 section for getting it installed, and I would head over to LS1tech for info on carb turbo setups.

[R3VO 3VOM]

Now my question is why not use a 350 v8? I have found plenty of information on a 350 swap into a 280z and it looks like its very straight forward, just a weekend if you have all the parts and kits. However I am having issues finding info about putting a turbo on a 350, looking at pictures there should be enough room in the engine bay. From my research I have found information on putting a turbo on a carb using a blow through carb from demon. Now this process looks simple, I dont think you need an ecu to manage anything because the carb is adding more fuel based on boost; is this true?

The sbc 350 V8 swap is very easy compared to other swap choices (an engine swap difficulty is relative to the individual). I did it in 2 weekends (but that's because I work slow and may or may not have missed the step about slotting the mounts). If you go this route JTR is your best friend.

 

Concentrate on getting the swap in before going turbo. You'll need more small miscellaneous things than you'll think you need. New fuel pump (EFI pump does not work with a carb), fuel line, filter, throttle cable, etc. Don't get in over your head and start counting your sheep early. You need the base before you can build anything else.

 

As for turbo carb, seems like you need to do a little more reading on the subject. I'm in the same boat as you only my swap is done. I'm looking at going turbo with my 350 V8 swap. Blow thru carbs aren't anything new. They have been around for quite a while. There's some good links on places like yellowbullet for how it works. You can buy a carb made for blow thru from places like demon as you said (although demon blow thru has horrible reviews. Quick Fuel and CSU have way better reviews. Roadkill uses a Quick Fuel on the Rotsun) or modify an existing carb like a Holley 750. If you modify one, then you have to start looking at fuel delivery in that you can jet up and run rich, jet down and run a secondary fuel delivery system (meth) or you can make it so the power valve (PV) works and it will run well. But remember, no carb is going to be optimized for your situation. You'll have to change the "settings", like tuning an ECU to best suit. Especially with boost. A wideband O2 is a must so you can know exactly what the engine is doing.

V8:

- Would a diff from a WRX hold up to the load of a v8 with a turbo?

- The little info I could find has a lot of 350's with twin turbo set ups, why is this can they run single? Could you fit 2 Turbos in with a v8 anyways?

 

V6:

- Would a v8 swap kit fit this V6 engine or is the engine mounts completely different?

- Could the stock fuel pump supply a v6 or upgrade?

- Does the WRX diff just bolt in? Looking at the video I looks like it, how about the shafts that go from the wheels to the diff?

 

The stock R200 will hold up fine to more than what I think you'll put down with a 350 sbc. Unless you go fully built high boost. But even then you'll run into limitations as others have said with the stub axles not the diff. The reason people use the WRX is it's LSD.

 

Twin turbo setups are easier plumbing for a V configured engine; you don't need a crossover pipe connecting the two banks (like the front pipe of the Rotsun that Fin welded together wrong). And they're generally better for response as you would use 2 smaller turbos. Downside is it's more expensive as you need two of everything. With a single you don't want to "choke" the engine with a small turbo but too big you run into lag. Plumbing is a little more complicated but you only need one of everything. (This is a basic basic version; there are many other factors when selecting what turbo to use. Big frame turbos can spool quick depending on other factors like housing size, exhaust, wheel design, etc.). The people running twins may have gone that way for the response, bragging rights, whatever. It doesn't really concern you. For all the twin turbo ones there are just as many single turbo ones. Packaging is always an issue with any engine swap in these small imports. There is technically room for two turbos or a crossover and one. Just how much fab you want to do.

 

The V8 swap kit may bolt on but it will sit very far forward as its made to account for another 2 cylinders. Stock fuel pump as I've said is an EFI pump and can't be used for a carb. The diff swap has been documented here on HybridZ (other options out there if you're only after LSD) but again if that's really a concern you'll start busting stubs before the diff.

Edited September 10, 2015 by R3VO 3VOM

[rajien2]

Wow just thank you for all the support, I am pleasantly surprised to get all of this feedback. Sounds like I am going 350 and I will work on the turbo side after the swap. I will be looking into JTR for the swap thanks again guys.

[seattlejester]

I think v6 because they had one rebuilt or maybe they got it and rebuilt it, don't recall exactly. They also placed the turbo in front by flipping manifolds, that wouldn't be as easy with an extra cylinder up there.

 

People have reported breaking the R180 input shafts, and johnc the creator has said that these axles aren't designed for more then 300hp/tq that is what the R200 and its beefier shafts are for.

 

The v8 is going to sound different with the same turbo as the v6 sounds, so if it is the sound you are going after you might want to do more searching.

 

You can turbo a 350, but blowers are more popular as they require a bit less work. The tendency is to turbo or vortex supercharge LS engines, but in our chassis a turbo v8 is going to put a lot of strain on a lot of things. This echoes back to rebekahsz comment, the car they had was in pretty bad shape, so they didn't care about structural integrity and such. 

 

In theory, a proper turbo carb will add more fuel with more boost as more air is passing by the carb. So yes it is in a way a self contained system. You will need to find someone pretty familiar with the setup though as it needs to idle and run rich enough in boost not to detonate.

 

Twin turbo's are popular for V8 since you have two banks. Put one turbo on each bank of 4. You can route all the exhaust to one turbo, but that is quite a bit of exhaust. Unless you plan on dumping quite a bit of it or running a small turbo past efficiency, you have to run a bigger turbo. Big turbo means lots of power which means other things break need upgrading. So those chasing big hp may run single turbo's but given the displacement you could also run two big turbo's it kind of never stops.

 

Short answer, yes you can run a single turbo on a v8, the problem is you will need a cross over pipe to connect both banks of exhaust. That means going behind the engine (most engines sit close to the fire wall so not possible), going above the engine (hood interference), going in front of engine (radiator, fan interference), or going under the engine (ground clearance). Since that is difficult people just run the twin turbo and keep all the piping pretty much to the sides.

 

The v8 can sit pretty far back in a Z, so you could mount the turbo's up front between the radiator and the engine. This will once again change the sound so keep that in mind.

 

The stock fuel will not supply a turbo v8, it will need much more capacity, also the stock fuel supply on your car is high pressure, for a carb you will need relatively low pressure.

 

You need conversion input shafts to put the subaru diff in as well as the front flange if memory serves. I think the studs are also different either in size or in spacing so you may need to take the back cover off of a datsun r180, you will also need an r180 mustache bar. Once again this is a bit of a down grade from the R200 so it may be better to just put an LSD in that and upgrade the axles.

 

I'm not sure your experience, but despite how they may portray themselves on the show, they have a lot and I mean a lot of talent to put behind their seemingly hap hazard installs. Some of the questions you ask are extremely basic, and this will take more then a weekend to install so I highly suggest doing a lot of research.

[crapforum]

Roadkill used the v6 turbo setup because they were trying to be cheap and ghetto (ended up not being cheap, but definitely ghetto). That 5 speed manual is a pile of trash, as you could see on the show they broke it very fast so don't think about using that if you are going to put any power down. Chevy v8 is the common route people take, I would also suggest it, unless you want to be JDM or something. Also running twin turbos does not mean faster spool time, spool time is all about turbo construction, and think about it this way if your using two smaller turbos your also getting half the exhaust spinning them up as opposed to one bigger turbo getting it all. You should ask how much horsepower you are looking for and that will tell you what motor and or forced induction to run.

You only need to worry about the axles breaking if your doing some hard launches with some sticky tires, and the car chassis can take plenty of hp. Mine has 480hp, stock r180,stock axles, and some rust on the floor rails (I wouldn't consider them frame rails on a 240z). The 280z is a tougher car too.

[seattlejester]

^Interesting how long have you been running that much power? Automatic or manual?

[Michael]

Coincidentally, I came across the "Roadkill" videos featuring their turbo-V6 Z literally yesterday, and noticed this thread today.

 

The show, like all shows, is intended to amuse and enthrall the audience.  It's not intended to pursue maximally wise engineering decisions or to build the best possible car for a given purpose, with a given budget.  That said, the show's stars are alumni of Peterson automotive magazines.  The main star was editor of Hot Rod magazine for a number of years, and has decades of experience in drag racing and Bonneville-style top speed racing.  So while the Roadkill Datsun is a horrible role-model of how to do a functional and reliable swap in a Z, it's amusing and a great plot-device for the show.

 

As others have said, a straight-up swap of the Gen-I 350 Small Block Chevy, based on the venerable JTR handbook, is probably the most straightforward approach.  For a 1978 280z, there is no need to worry about driveline robustness in the rear (unless it's an automatic; the automatics came with the weaker R180 differential).  The only challenge, which is not adequately covered in the JTR book, is what to do for a manual transmission, if you choose to run a manual.  This wasn't well-covered in the book 15-20 years ago (when this whole craze first went mainstream), and progress in intervening years has been minor at best, because the LS-based swap has overtaken the Gen-I swap in popularity.

[RebekahsZ]

I love Roadkill! I just wouldn't model my Z car build off of there's for anything other than tongue-in-cheek humor. I love how the show documents the frustration, determination and frequent failures that accompany this hobby. On cooking shows, the food is always good. On fishing shows, they never fail to catch fish. On Roadkill, sometimes their shit breaks and they work all night and miss the race-that's reality TV.

[rajien2]

Hey guys thanks for all the information, I might come off as wanting to make the car just like the rotsun however I really just like the turbo aspect. I have the JTR manual on its way now, I hope to have it by friday and start diving into some details. Now the part about the manual transmission not being very well explained makes me a little nervous... However I have done some reading that using a T5 from a mustang is a good way to go, can anyone confirm this?

 

Thanks

Cody

[R3VO 3VOM]

Not from a mustang. From a V8 Camaro. Difference is the bellhousing pattern and subsequent matching case pattern.

 

V8 Camaro T5 bolts on. Mustang T5 you'll need an appropriate clutch disc and either an adapter to use a chevy bellhousing or an aftermarket bellhousing that's drilled to accept the mustang T5 pattern. Now there is talk of rare bellhousings that allow mustang T5 trans to bolt to a chevy pattern engine (I think they were "ironduke" jeep housings but not 100% sure) but these are hard to find.

 

Just going Camaro T5 makes your life easy with the swap. V8 Camaro T5 is what JTR recommends for a manual swap.

Edited September 16, 2015 by R3VO 3VOM

[rajien2]

Oh very cool thanks that would have been a big pain! Ahhh alright so what im gathering... Just go buy a complete V8 Camaro and just sell the shell later.

[Michael]

 Now the part about the manual transmission not being very well explained makes me a little nervous... However I have done some reading that using a T5 from a mustang is a good way to go, can anyone confirm this?

 

 

The trouble with the T5 is its rather paltry torque capacity.  This has been discussed at some length in the "drivetrain" subforum.  Even JTR admits the questionable torque capacity of the T5.  However, I've not heard testaments of the T5 breaking - at least not on this Forum. 

 

There are aftermarket suppliers who rework the T5 for much higher strength; see for example http://www.gforcetransmissions.com/tran_gt-5.asp .  It might be a reasonable strategy to do a normal T5 swap, see if it breaks, and if so, do the upgrade; otherwise leave it alone.

 

Yet another issue is the bellhousing.  I ended up with the very heavy but very strong Lakewood unit.  It's strictly aftermarket (see Jegs or Summit), but should bolt to the T5.

[Chris Duncan]

 You do realize that's a 2+2 so it's a little different from the Rotsun

 

Also if you go 350 Chevy it's going to be heavier so you  way want to upgrade brakes and suspension. You might look at aluminum heads before you go turbo. Some AFR's would give you added HP and get you back to stock weight.

Edited September 23, 2015 by Chris Duncan

[rajien2]

 You do realize that's a 2+2 so it's a little different from the Rotsun

 

Also if you go 350 Chevy it's going to be heavier so you  way want to upgrade brakes and suspension. You might look at aluminum heads before you go turbo. Some AFR's would give you added HP and get you back to stock weight.

Yeah thats okay with me more room for a cage and more trunk space.

 

Oh totally I have been going through my manual nightly, I have a rebuilt steering rack for a forester with celica tie rods coming this week. I should be ordering the truck brake pistons some time next week. I hope to be ordering a crate engine from summit here in the next few months, I will just pick up a T5 from a junk yard and buy a rebuild kit. I am still working out what im doing on suspension, I might just get some coil overs and an aluminum mustache bar. Depending on how much roll there is will determine the roll cage I will be using.

 

The trouble with the T5 is its rather paltry torque capacity.  This has been discussed at some length in the "drivetrain" subforum.  Even JTR admits the questionable torque capacity of the T5.  However, I've not heard testaments of the T5 breaking - at least not on this Forum. 

 

There are aftermarket suppliers who rework the T5 for much higher strength; see for example http://www.gforcetransmissions.com/tran_gt-5.asp .  It might be a reasonable strategy to do a normal T5 swap, see if it breaks, and if so, do the upgrade; otherwise leave it alone.

 

Yet another issue is the bellhousing.  I ended up with the very heavy but very strong Lakewood unit.  It's strictly aftermarket (see Jegs or Summit), but should bolt to the T5.

 

Oh very useful thank you, I will just rebuild on from a junk yard and if I blow it up then I have a solution thank you sir.

 

As always thanks for all your help guys.

[Midri]

Just watched the 24 hours of LeMons episode, god I wish I had the balls to destroy my exhaust and side panels to make it look like how they did.

Edited September 26, 2015 by Midri

[crapforum]

Depending on how much roll there is will determine the roll cage I will be using.

 

ROFL, that's not quite the purpose of a roll cage. Don't buy a crate motor whatever you do, the SBC platform is WORTHLESS! The only thing good about it is the low cost which you are completely eliminating buy getting a crate motor. I had a 350 small block and thought it was great and then after dumping a small fortune building on it to be a beast it underperformed and did not last long. The SBC will start leaking oil eventually no matter what you do and are not made to last 100k miles like the ls. Sorry to all you guys running them but they are just so bad now as you can get a truck ls motor for the same or less. Get with the times and stop being afraid of computer controlled engines, they complexity of the wiring is easily offset by the simplicity of the mechanics (no more valve lash adjustments!)