Here's the easy question. What engine should I run?
Ah, if only.
Swapping engines is often the way of the 510 owner. Due to desires for more power, EFI, increased reliability, or to have that trick swap underhood, there are many reasons to swap in a different engine, many different engines to choose from, and many different ways to get it done. What needs to happen between asking the question above and turning the first wrench? Everything.
Similar to doing body work in preparation for paint, preparing for an engine swap can make or break the final result. Someone new to 510s may not know which engine swap will suit them best, and that’s part of the reason we’re here at The Realm. Chances are very good that someone has swapped in whatever engine you’re dreaming about, no matter how oddball the swap. However, the chances of you having the same mechanical skills, fabrication abilities, budget, and experiences as the person who did the swap you’re planning are low, so it won’t be helpful for us to suggest that path if you can’t complete it.
Instead of asking the short question of “what engine should I run,” read through the following points and see how you fare. The worst thing you can do is buy a 510, buy a small-block Chevy, cut the 510 so you can maneuver the engine into the engine bay, then realize you don’t have any idea where to go from there.
I’ve written previously about the process of successfully planning for a big project, and make no mistake, an engine swap is a big project. Read through this here:
Some of the key information we’ll need to answer the question at top involve your budget for the project, how much mechanical knowledge you have, an idea of your fabrication abilities, and the time and space you have available for an engine swap. These basics will determine your success, before you even get to engine choice.
Budget: If you have $1000 in total, we can quickly rule out most swaps beyond an L20B. When you report your projected budget, we understand it’s a ballpark figure – and it’s rarely an excessively-high one. We’ll need to know what you think your projected budget will cover, and in concert with all the other information you’ll provide, we can give you an idea if your budget is sensible or fantasy.
Mechanical Knowledge: Have you ever rebuilt an engine? Have you ever removed and replaced an engine/trans? How are you at reading electric circuit diagrams, wiring, and troubleshooting electrical components?
Fabrication Experience: Do you weld? Do you have the know-how to make engine mounts (taking into consideration fore/aft placement of the engine, engine angle, engine tilt, engine height, etc.)?
You may have family/friends who have mechanical and fabrication skills, and they may even suggest they’ll help you out. And they may. But count on the project taking much longer than anticipated and running into periods where nothing is getting done because you’re waiting on someone else to help you. If you can’t do everything yourself, you need to reevaluate the time and budget for this project as they’ll increase. Often substantially.
Time and Space: Engine swaps can take a weekend if you’ve done the same swap 20 times and nothing goes wrong. Engine swaps can take years if other priorities (family, life, the unexpected) take precedence. Generally engine swaps (from an L-series to a KA, say) take a few months. Do you have the proper space (i.e. not a carport in Oregon in winter) and use of that space for at least twice as long as you think you’ll need?
As mentioned above, we’ll need summaries of those points so we can consider them in our various answers to your easy question. It matters.
Limits on engine choice have much more to do with your budget and mechanical/fabrication abilities than anything else. Ask not if it can be done, ask only if you can do it. Even engines generally considered as oversized (Subaru flat-four, Nissan RB-series inline six, Chevy V8) have been stuffed into 510s.
Engine choice can be narrowed down with one major question: Nissan, or non-Nissan? Some people are brand purists and will only condone the same name on the cam cover as on the trunk lid. Most here at The Realm care more about successful swaps; we want to see and keep these cars on the road. If you want a Honda F20 swap, no one is really going to flame you for your choice – IF you pull it off.
Nissan engine swaps in 510s are much more common for many reasons, but one big reason is that they’ve long ago reached critical mass. There are enough CA, KA, VG, and SR swaps done that all the bugs have been worked out of the process. When you go outside the brand for your choice of engine, the number of people here at The Realm that can assist when things go wonky decreases dramatically. Of course, there are likely forums for whatever engine/brand you choose, but just understand that The Realm may not be able to help if you’re trying to defeat the security issues surrounding the F20.
With all that said, I’ve previously co-written a pair of articles laying out the basic power, weight, sources, and characteristics of Nissan engines. Reading through these can help you exclude certain engines, or put certain others on your list. Get over to The 510 Archives / Factory Information / Club Newsletters and read through:
DQ Volume 7 Issue 2 – Engine Swap Guide: Part One -- The long-awaited round up of Nissan alternatives for your stock L16, including weights, dyno figures, and owner impressions of selected engine swaps. If you are trying to decide which engine to swap into your 510, this article is for you
DQ Volume 7 Issue 3 - Engine Swap Guide -- Part Two - Japanese domestic market Nissan alternatives for your stock L16, including weights, dyno figures, and owner impressions of naturally-aspirated and turbocharged SR-series engines. If US-sourced engines are too common for you, here are some tasty alternatives.
Nothing has really changed for Nissan engine swap candidates in the last decade. The QR is out there in RWD, but isn’t a popular swap for 510s as of yet, so you’ll be much more on your own in getting this to fit and run.
If you’re still not sure which engine swap is for you, or if you’re more interested in non-Nissan swaps, keep reading.
Now we’re getting into the nitty gritty. For us to make cogent suggestions, we need to know everything we’ve asked so far, but we also will need to know what you want out of the engine. This topic has many sub-points, so we’ll break some of them down.
Power: It would be helpful to know if you’ve ever driven/ridden in a swapped 510. We often get new 510 owners looking to swap and state a desire for 400WHP. This has been achieved, but is generally considered too much power for the car. Also, many new 510 owners are coming from other modern – and much heavier – cars. If you have a 3500lb Camaro with 400hp, you’re not going to need anywhere near that power to have a 2100lb 510 just as fast.
Since most of us do engine swaps for the often-times large power increases, what sort of power are you looking to make? If possible, please clarify whether you’re talking crank HP (CHP) or wheel HP (WHP). There’s a generally-accepted 17% drivetrain loss in a 510 to account for the difference between the two. For most, what you have at the wheels is what matters, but it’s also easier to get to a 200CHP KA24DE than to see 200WHP from the same base engine.
Powerband: Do you like torque? Do you like a high redline? There’s much more to power than the peak number – in fact, since few of us spend any real time at peak power in our cars, it could be said that there’s nothing but bragging rights in peak power numbers. It has also been said that people “buy” horsepower (as in, big HP numbers), but “drive” torque. If you want serious backside g feel from low rpm when you step on the gas, you want a larger-displacement engine. If you want that turbo hit, nothing else will do. If you have to spin the engine to 8,500 to feel alive, that will help us point you to the right engines for you.
Daily Driving: How you will use the car should be forefront in your mind when dealing with the decision of which engine swap to choose. If the 510 will be a daily driver, that usually eliminates highly-strung engines such as a race-spec Rebello L-series or an SR with a fat turbo. If you’re building a track-day weapon, a lack of mid-range isn’t going to matter, and neither will fuel mileage.
None of the modern engine swaps will dramatically improve fuel mileage over a carbureted L-series that has been maintained, so the financial payback of swapping from a highway high-20s-mpg L-series to a 31mpg KA24DE is next to never. Of course, you get double the power with your slightly better mileage, and city mileage is likely to be much improved.
I realize that this whole process seems like a huge pain in the ass just to get an answer to your easy question. Hopefully after reading this you’ve realized how difficult your “easy” question really is. Then think about the money and time you’re going to put into this swap. Why wouldn’t you spend a few minutes reading through this and figuring out the answers to what’s been asked above?
You might as well, because we’re going to ask anyway.