Hey Everyone!!!

I've got an idea that probably hasn't been done yet...probably for good reason.

 

I'm really wondering about fitment. My stock v6 is pretty huge but I'm worried about the shift lever lining up(I'm hoping to go automatic since fuel efficiency is my goal here). I don't think engine width should be an issue. I know the 2.0 is underpowered so I'm planning on turbocharging it with boost kicking in after 3500rpm. Or I'd go with the 2.5 and keep it NA for a while(that'll only be a bit weaker than what I have now but I'll be cutting 300lbs off the car).

 

 

My GFs father is going to be helping me. He's an industrial mechanic(good welder, decent with wiring things) and restores vintage tractors for fun. I have a degree in metalworking which won't really be of much use and I'm not super mechanical. We're expecting tons of issues making the gauges work but I'm hoping someone here has some good tips!!!

 

The goal is RWD, roughly 210hp when I'm boosted(no more than 240 or so) but the main goal is over 35mpg on the highway. I know few here mod for efficiency but you'll all be of more use then me if you've done Subaru swaps and RWD conversions.

 

 

*I've always wanted a 300zx(since I was little). Now that I could afford one, I'm super interested in clean emissions along with gas mileage. I'd love to meet modern emissions standards with my Z(I just bought it and have a good 4-6 weeks of bodywork before I paint it).

Edited April 4, 20188 yr by Veganpotter

there have actually been similar swaps done. there's an ej22 powered rx7 on here, i build an eg33 powered mustang a decade ago. im currently building an sti powered miata

 

if you're aiming for MPG- the subaru automatic will be  HUGE disappointment. and will require AWD

 

 

You can adapt a subaru to a toyota R series RWD trans to achieve RWD. you'll want a manual for sure

 

wiring is simple, millions of stand alone write ups, you can make the engines run anywhere. gauges are easy as well, nissan and subaru use similar set ups in that regard. or just ditch the OEM gauges and run after market.

 

i personally would suggest a 2.5 block with 2.2 heads, a mild cam. that will yield 165-180 NA hp. but will not be turbo friendly,  search frankenmotor. they're tons of fun and cheap as dirt to build

Very interesting project, ambitious but certainly doable.

I do want to start with a reality check.

I know the Z is an aerodynamic car, which will help on the freeway, and I know that going from the Iron-block V6 VG30DE to an all-aluminum 4 will save you some weight (I'd guess 200 lbs or so), but you'll still have a pretty heavy car (quick google search says curb weight of 3300lbs). I don't think you'll get anywhere near 35mpg with a Subaru engine, even in the best conditions. Subaru engines are not terribly fuel efficient, certainly not in stock tune.

Assuming we're looking at a budget-friendly engine swap (I assume that since we're talking about fuel mileage, this is the case) that will probably cost $2-3k depending on the details.

Anything newer than 2005-2007 (depending on the exact model/trim) will have an immobilizer, which pretty much puts it completely out of this category unless you're extremely knowledgeable and get some seriously valuable parts for free. Subaru didn't offer a non-turbo 2.0 until 2012.

The hard part will be the transmission. Conventional automatic transmissions are not efficient, and modern ones that are require some serious computing power to run them (and Subaru doesn't make in a RWD configuration, so you'll be mixing and matching manufacturers. good luck!). Without fabricating your own engine-transmission adapter, your best bet is probably BRZ/FRS/GT86 transmission, or using one of Bill Hincher's adapters to an older Toyota transmission.

The next issue is width. Horizontally-opposed engines do not typically fit well in engine bays not designed for them. I wouldn't be a bit surprised if it wouldn't fit between the upper control arm mounts.

Gauges are one of the easiest parts. Tach signal converter to get that to read right. Might have to put the Nissan temperature sender in the Subaru engine. Speedometer might be a challenge depending on the transmission, but still completely doable.

 

If I were to engine swap a Z32, with 35mpg the goal on a budget. It would be a manual transmission. If it had to be gas, I think it would be a Honda engine. But I would be pushing very hard for a VW TDi. I know there are transmission adapters to Toyota longitudinal transmissions (see them all the time in 4WD trucks, bellhousing would be the same for many RWD Toyota transmissions). Stock tune would likely yield 45mpg+, and with some mods 60+ isn't off the table.

Very cool idea. I have a Z32 myself. Great cars. To see one with a Subaru engine, and it gets 35mpg? Awesome!