Stroked Engine, Piston Swap, And More - Import Tuner Magazine

Got a burning question or simply need some advice with problems you’ve encountered while wrenching on your current/future projects? Ask our automotive guru Eric Hsu anything—literally, he’s going to answer every single question, as long as it’s automotive related.

Got a tech question? Send it to questionit@importtuner.com

Practice What You Preach

I happened to browse the latest June issue of IT and came across the ARK BNR32 you are building for this year’s WTAC in Australia. I was surprised to find out that you’ve decided to ditch the RB26DETT engine and replace it with a Nissan VQ35DE. I know you’ve preached in the past to not “reinvent the wheel” with engine swaps and costly makeovers but you seem to be going back on your words with this new project. Care to share your thoughts and reasons on why you decided on taking the potent RB and swap it with the VQ?

-Brian King, via importtuner.com

When I give advice in Question IT, I have to take into account the average person’s abilities and resources. I want people to enjoy their cars and not create expensive money pits that they’ll come to hate or dislike rather than enjoy. In general, if you’re writing a columnist on how to swap an engine, then chances are you have no idea how to. Sure, the average person could take the time to learn, but it’s not like you’re learning how to play a board game that costs $20. The person would have to take a lot of time and thousands of dollars that he could be using on other fun things like chicks, wheels, and going out or just enjoying his car as much as he can with the existing engine platform. Also, I firmly believe that engine swaps should be based on logic. Oftentimes swapping a heavy longitudinal straight-six engine into a front-wheel-drive platform (or even rear-wheel drive) is not a swap that I would consider logical due to costs, physical space limitations, and the fact that the swap would ruin a car’s handling.

In our case, we have a financier, a team of engineers with access to CAD workstations, complete workshops, machine shops with CNC and CMM machines, and several badass mechanics. So our situation is considerably better than the average person reading this magazine when considering the fact that we have the ability and budget to redesign the car to our purposes. In this particular case, replacing the tall, heavy, smaller displacement RB26 with a more modern, compact, and lighter weight VQ35HR is a logical swap for the BNR32 Skyline GT-R. Plus we have a goal: to build the fastest time-attack car in the world. We’re not building a car to blast around on the street or to have some cool-looking forum signature.

Stroked Engine Advantage

To stroke or not stroke my 4G63 Evo IX engine—that is the big question I have been debating for the last few months with my upcoming engine rebuild. I can see why owners have favored stroking their engines to bump up the factory 2.0L mill for improved boost response and bottom end torque, but are there any drawbacks on increasing the displacement for a daily driven car that’s occasionally taken to the track?

-Todd Wolf
Orange, CA

This is a topic where depending on who you talk to, you’ll get a different answer. I believe increasing stroke to a certain degree is a good thing. Increasing the stroke too much will increase piston and bore wear, reduce the engine’s maximum rpm, and make an engine rougher. It’s also important to take into account the purpose of the engine. For racing, I believe that in the 4G63’s case, increasing the stroke to the popular 94mm would be a good thing whereas increasing to 100mm would be too much. A 94mm stroke is a good balance and offers gains on the bottom and top ends of the powerband without much sacrifice (other than your wallet getting thinner). For the street, a 100mm stroke would be fine if you keep the revs under 7,000 rpm. Setting the limiter to 7,000 rpm is the key to preventing excessive wear on the engine and keep it alive longer. The engine will be a little rougher and have some more vibration, but if you’re OK with it, then go for it.

Quick Fix

I own a ’06 Infiniti G35 coupe 6MT. I’ve only had it for a couple of months but the previous owner did hardly any maintenance. The mileage is increasing so I hoisted the car on some jackstands to do a tranny and diff fluid change. Unfortunately, both fill plugs are extremely tight and already almost stripped. Before I yank on it anymore, do you have any tips for how to get it out? It’s a 10mm hex Allen socket. I called a few shops but they were not really any help, basically just saying bring it to them so they can make some money. Any help is much appreciated and keep up the great work!

-Brandon
Edmonton, Alberta, Canada

If I remember correctly, the 6MT trannies have a drain plug with a flange that protrudes from the casting. You can grab a metal file and file two flats on the drain plug. This will take some patience of course, but then you can file the flange of the plug to fit a standard open wrench (e.g. 19 mm). If you have more money than time or have no patience, then your only other choice will be to go to one of the shops and get it removed. I’m pretty sure they aren’t trying to rip you off either. This kind of work is a pain in the ass and prevents them from simpler work that makes them good profit margins.

Power Check

I just purchased a Datsun 510 and decided to go with a simple, yet proven swap: the SR20DET. My goal is to achieve 300-350 whp. Do I need to upgrade the internals to reach those horsepower numbers, and if so, what needs to change?

For 350 whp on an SR20DET, you should be fine with the stock internals as long as the ECU tuning is good. What you’ll need to achieve your horsepower goal is a turbo upgrade such as the Garrett GT2860, a good flowing exhaust, ideally a larger than stock intercooler, and a good ECU tune. While you’re at it, I’d recommend a pair of small cams such as the Tomei 260 duration Poncams and a Cosworth FSL head gasket for longevity, since the factory paper gaskets are pretty weak and old in the used engines from Japan. Good luck, it’ll be fun as hell to drive when you’re done!

Reader Feedback

Just picked up the May issue of IT on my way into my workshop and was having a quick browse through the tech section when I saw Michael Rafuse’s question about tuning for the FC RX-7. Since I specialize in rotaries, I felt I had to drop you a line and bring to your attention some of the latest tech available for tuning Mazda’s masterpiece. I noticed that Eric recommended the Haltech 1000 ECU for tuning the 13BT. I have experience with installing and tuning this ECU, and while it’s definitely a good option for the same kind of cash or even a little less I would have pointed Mr. Rafuse to the Link G4 RX ECU; this unit is a dedicated rotary ECU and is far more capable and configurable in my experience. It also provides for 4-D tuning, which can save you a rebuild or two in the future.

As for a budget of $6-8K, these days you can pick up a plethora of bolt-on mods and/or go for a rebuild. You can pick up good quality high-carbon Apex seals these days for anywhere from $400 for a full set. Lastly, while a few good nuggets of info can be found on the forums, the majority of advice is what you call “quick fixes”. I applaud backyard mechanics (we all have to start somewhere), but there comes a point where people should stop dispensing advice and tell their friends to seek out a shop with people who know what they’re doing. Thanks for producing a great magazine guys; I look forward to it every month.

-David Drummond of AVA Customs
Honolulu, Hawaii

I have heard that the modern Link ECUs have taken big steps forward compared to earlier ones from the mid/late ’90s, which were probably a tad bit faster than an Atari 2600. I have not had the opportunity to use a modern Link ECU, however, but I’m sure they’ve taken a huge step forward since they’re still in business and the consumer-grade ECU world is so competitive these days. I do know of quite a few successfully tuned rotaries on the Haltechs without issues, which is why I recommend them. I can only recommend what I have experience with or know firsthand, but thanks for sharing, David. In the tuning world, there are many ways to skin a cat.

For $6-8K, however, Mr. Rafuse would not be able to get a stand-alone ECU, rebuild his engine with carbon Apex seals, and get the plethora of bolt-on parts. I’d imagine a budget of $8K would only get him the ECU, installation, dyno tuning, fuel system upgrades, intercooler, and maybe an exhaust system at a reputable tuning shop.

Piston Swap

I have read somewhere in an automotive book that Honda engine parts are interchangeable on a B-Series engine, but what about using pistons from a B-Series to a D-Series D16Y8? I am planning on rebuilding my engine and would like to get the facts straight before I begin ordering parts.

-Mike Valencia
Placentia, CA

A simple search on Wikipedia will tell you that a B-Series 81mm bore would make it pretty difficult to fit B-Series pistons into the D-Series block, which has a 75mm bore. You might consider going with a set of lower cost forged pistons such as the JE SRP line. You can do a small overbore (0.5 mm) and step up the compression to 11.0:1 and make more power that way.

WTF!

Hi Mr. Guru Eric Hsu. I hope you are good. I have a simple but very important question. I own a ’90 Nissan 240SX that’s a drift project. What can you tell me about it or recommend I do to it?

-Andres, via importtuner.com

IT: Eric, don’t answer this question.

Eric (responds anyway): People don’t do their own research these days or what? He took the time to type multiple sentences when all he had to do is Google “Wikipedia Nissan 240SX”.