Choosing a 987.2 Foundation: Rev-Happy 2.9 or Torque-Rich 3.4?

I’m trying to decide on the right starting point for a 987.2 project and would appreciate experience-based feedback before I commit to buying a car. The choice is between the 3.4L for its torque and effortless performance, or intentionally building around the 2.9L with a focus on engagement: lighter feel, sharper throttle response, higher-rev character, and an engine that rewards being worked rather than short-shifted. This isn’t about dyno numbers or outright speed, but about building something that feels alive and involving on back roads and track days. One technical factor pushing me toward the 2.9 is that it’s port-injected, which makes future options like ITBs and more aggressive intake work far more feasible than with the DFI 3.4. I’m also aware that many well-executed 3.4-based projects already exist, and part of the appeal of the 2.9 is exploring a less common, but potentially more character-driven, foundation. I do plan to invest significant money into the car, so I’m also thinking about how this choice is viewed long-term. For those who’ve owned or driven both, or who’ve gone deep on modified builds: does a well-sorted, rev-happy 2.9 feel like the right foundation for this kind of project, and do you think enthusiasts would recognize and value that approach if the car ever changed hands? Or does starting with the 3.4 still make more sense in the real world because of its torque and broader market appeal? I’m trying to pressure-test the direction before spending real money and would value driver impressions over theory.

If you will mostly drive on the street, the 2.9 is a fantastic choice. If you will use it at the track, I would recommend the 3.4. Why? There are tons of 981 ’s with 3.4’s at the track. A 987.2 with the 3.4 is competitive with these. It’s simply nice to drive in a similarly capable car. I know this might seem like a weird reason, but it’s a lot of fun to drive a DE session where there are many similarly capable cars. I have a few friends with the base engine and they wish they had a 3.4. The 3.4 is also fairly competitive with many faster cars like some 911 ’s, C7 and prior Vettes and even the 981 GT4 . So again, when driving on the track, the 3.4 is in the mix rather than simply being passed by most cars. One other factor is financial. If you are investing in a lot of mods, the cost of the mods will be similar regardless of which engine you select, but the resale value is better for the 3.4.

Yes ok thanks, this is exactly the type of discussion I wanted to have. I was thinking some similar thoughts, that a downside of the 2.9 was that it may not be as competitive on the track, although I am going to be 95% street. On the other hand, I’m very much of a “driving a slow car fast” is more fun, so do not want too much hp. I’m also trying to lighten the car as much as I can while staying civilized, hoping to get 100 lbs out. 2.9s tend to be lighter. Other benefits include the shorter gearing, lower options (for both weight and price), same size brakes, lower price. So I guess if you’re advocating for the 3.4, the question is, can you modify it to have the same character as the 2.9. ITB‘s will be much harder as far as I can tell with the DFI, but are there other ways to get the same type of zing from the engine?

Maxhouse, from everything you are saying, I have a feeling your will absolutely love driving on the track, and it will eventually become more than 5%. Driving is all about getting the most handling and braking from the car rather than raw HP. In the current big picture, the 3.4 liter Cayman is already the low HP car that performs well due to light weight and nimble handling, at least in comparison to most of the cars at the track. In most run groups, 300 hp is pretty much entry level these days. There are certainly mods to get extra power and performance. One thing that made a big difference for me was a Softronic engine tune. It provided a bit more HP, but the biggest difference is increasing the rev limit from 7500 to 8000. The 3.4 liter can go to 8000 with no problem, but Porsche held it back in the Cayman . That extra 500 rpm of rev really changes the driving experience. These cars are happiest at the high revs. What do you mean by ITB's? What track would you visit?

@Maxhouse97 - Especially if this will be your daily driver, "driving a slow car fast" is the way. Insanely low temps currently in Boston, and I'm driving mine with winter tires and the unobtainium hard top. It's awesome. Also took a 4250-mile trip in November, and I'm not losing sleep over any bore scoring -- it's got 265K+ miles on the engine. 3.4L+ is great (I also drive a 3.8L 981 Outlaw track weapon), but I enjoy everyday high-rev street action without going to jail speeds. YMMV, and lots of great threads on this. No wrong answers. Stay tuned for more articles about the 2.9L -- I'm busy writing them. Cheers.

I modded my 986 significantly and had a blast doing it. However, IMO, buying the power from Porsche is better and preserves value too. I enjoy the 3.4 especially on trips, but there is nothing wrong with enjoying a 2.9. I began shopping for a new DD to be prepared, while I’ve been gone from that pursuit? Every entry level vehicle has been fitted with a proper motorcycle engine, you’re fine with either choice.

Ok so a little more about myself … I already have a dedicated track car (E46 M3 ), I track (DE) about 3 times a year. I also have a 718 GT4 and a M2 Comp as a daily. So hence my thought that I don’t want too much power. I grew up driving Miata ’s and had a 987.1 3.4 with less than 300. My goal with the 2.9 would be 300hp, 2900 lbs. I also love short gears (I re-geared the GT4 and it’s life changing). This is another advantage of the 2.9. Guess I need to decide whether I keep the M3 as a track car or try to dual purpose this cayman . I don’t track the GT4 , it’s my forever car. I agree the 3.4 would be better for the track. I do acknowledge that I may not have this car forever, so I am asking for enthusiast opinion here in case I have to resell. I anticipate investing a lot of money (as I mentioned above) in the build I want to do, so don’t want a unicorn that can’t sell afterwards. The appeal of the 987.2 2.9 in the type of build I’m thinking (“R-lite”) isn’t chasing peak numbers or trying to out-3.4 a 3.4, it’s about creating a lighter-feeling, higher-revving, more responsive engine that stays happy doing hard laps all day. The 2.9’s port injection, lower rotating mass, and better thermal margin make it a natural fit for a motorsport-style approach: sharper throttle response, usable revs, and power that builds cleanly to redline rather than leaning on torque. You’re trading a bit of straight-line punch for a calmer, more transparent engine that rewards momentum, precision, and driver input—closer in spirit to a junior GT3 than a tuned S. On the street, that character often matters more than the extra horsepower, and it’s why the 2.9 makes sense if the goal is feel, consistency, and engagement rather than dyno wins. ITB = individual throttle bodies

Well, it if helps any with your decision making, @Maxhouse97 - I save my 3.8L (991.1S engine in 981 Boxster) for insane fun -- not to mention that it has the short gearing. It was literally built as a track weapon (and is now a bit of a show car) as the 981 Spyder hadn't been built yet. Meanwhile, my 2.9L is the opposite for just high-rev fun. They're different enough to justify keeping both. (I also have my '92 E30 'vert, but both outperform it.)

Sounds like you already had a remarkable plan Maxhouse. I bet that GT4 is a rocket.

Lots of tough decisions. From what you are describing, the 2.9 sounds like the way to go, especially so if it’s going to be 95% street driving. I was wondering if ITB was referring to throttle bodies. I’ve never heard of that as an upgrade for a 987. Interesting. Who makes it?

I don’t think there is a plug and play kit, would require some development from someone like Jenevy or Kinsler. This again would be great as ITBs seem to bet only available for air cooled Porsches, but it would be awesome to have in a Madden m modern water cooled car.

Will all your driving be at near sea level? I have a 987.2 with the 2.9 and it's plenty to have fun on public roads near sea level, but on mountain drives in CO it becomes marginal very quickly. Just an added thought. I personally would go with the 3.4.

Mostly sea level for sure, I live in Cincinnati

If I had to pick an ethos from the current retsomod crowd that is inspiring me for this build (although completely disconnected from the reality that I live in due to price), I would say it’s more Tuthill 911 K (350 hp) and KAMM 912 (~200 hp) than Singer (400+ hp). Kind of like a 992 .2 Carrera T as well.

Key thing to remember is that the 2.9L runs on Skyline Chili. If you get the 3.4L, you'll need Gold Star. Don't mix them up. However, Graeter's ice cream is a perfect coolant for either.

now you've done it, you've started the Great Cincinnati Chili War!!!!!

ITBs = Individual Throttle Bodies While I do see the benefits of them on many a car, I’m convinced nobody goes this route on the 987/ 981 platforms for good reason. I’d assume you would have to remove the carpet, insulation and engine cover to get enough room and then you would need a custom GT4RS style intake system to feed them fresh air. I’m wondering if you could achieve your goals with an IPD plenum , GT3 throttle body , tune and maybe a lightweight flywheel. 2.9L Caymans were raced professionally and competitively here in the US in the IMSA Continental Tire Sportscar Championship. It is my understanding that the engines were basically stock since they were racing against lower powered cars like BMW 128is, Honda Civic SIs and Mazda MX5s. A friend of mine was racing for Mazda at the time and had some great battles with the Caymans . So, as a 981 2.7L manual owner myself, I’m going to have to support the less displacement/more revs option here.

I’ve owned both a 987.1 S (3.4) and 987.2 base (2.9) and I definitely understand the dilemma. I grew up driving muscle cars and low RPM torque is transformative to how a car feels, particularly in day to day, in-town, stoplight to stoplight driving. But the 2.9 feels so good revving out. I understand….. I love Honda high revving engines, but equally BMW straight six torque, etc. Also naturally aspirated V6s, and contrastingly high torque turbo fours. But in the end it’s the low RPM torque that will win almost every time for me, and the overall higher HP of the 3.4 is just cream on the top. If you’re looking for something that pleases you the most, go for what enthralls you. Can’t really go wrong with the 2.9 if that’s your choice. If you’re looking for something that might appeal to most enthusiasts (selling the car later) then the 3.4 seems like the way to go.

I bought a 2.9 because it was 2015 and I was 23. I attempted to drive it in the winter but nope. Now I’ve gone heavy on the mods and I don’t regret it. Sure the 3.4 would feel more hefty but I can have more fun winding it out on the streets. If you plan to track it, absolutely get the 3.4. But as a street toy you can play with, the 2.9 ticks all the boxes

I have a 2009 Boxster 2.9 m6 and it's great fun driving on the 2 lanes. I tested a 3.4 and preferred the 2.9, had no need of the extra power. I rarely floor my 2.9 for that matter. No track use, yet.

I say follow your gut and go with the 2.9 and explore. If you could replicate the GT4 RS engine rev behavior and drivability at 2.9L that would be an amazing build. The RS engine is something I didn't understand until I experienced it. The computer works hard just to make it idle!! (I assume due to the lightweight flywheel)... and the revs build so quickly with no torque drop off. The lower gearing in the GT4 RS is also a key feature to chase... My 981 Boxster would be sooo much better with lower gearing. With the modifications you are considering the resale won't be to a simple 'I want an S because S is better' buyer so the raw numbers will mean less. My 2 cents.

So for those that are interested, here is the email I sent a well known shop and their response: Hi - thanks for the great conversation over the phone today. I now have a better appreciation of the challenges of incorporating ITBs on a modern fuel injected engine. I’ve moved past that and would like to focus on which platform to start with. I’m planning a lightweight, driver-focused “ Cayman R-lite” build based on the 987.2 generation and would really value your opinion on whether the 2.9-liter or 3.4-liter platform is the better foundation when the goal is engine character rather than peak performance. The intent is meaningful weight reduction (roughly 150–200 lbs), strong throttle immediacy, and an engine that feels alive and engaging at real-world speeds. Factors I’m actively weighing include gearing differences, rotating mass, rev response, and how each engine’s torque delivery shapes the overall driving experience on the street (the car would be ~90% road, ~10% track). From a technical standpoint, I’m especially interested in how the two engines differ as modification platforms for building character. The 2.9’s port fuel injection versus the 3.4’s direct injection raises questions around intake design freedom, tuning flexibility, sound quality, and long-term serviceability, particularly if one prioritizes throttle response, induction noise, and a more mechanical, analog feel. Engine sound is an important part of the experience for me—specifically clarity, induction presence, and how the engine builds and changes tone as it approaches redline, rather than sheer volume. My concern with the 3.4 is whether its additional power, DI constraints, and taller gearing inherently push it toward a GT-style personality, whereas the 2.9 may be a better canvas for a high-revving, responsive, emotionally engaging engine—even if ultimate output is lower. Based on your experience, which engine do you feel is the stronger starting point for turning into a truly characterful, R-lite-style powerplant, and why? The response: The 3.4 DI engine is a decent starting point. Most of our experience is in the GT car power plants. Oiling and valve train dictate the high revving nature of an engine. The 2.9L is a “base” engine and will not have the necessary parts inherently to be a high reving engine beyond its stock redline. Reinventing the wheel can be fun, but it’s also quite expensive. I’d stick closer to a 3.4L DI engine, you can get power out of them readily easily… Thoughts?

Hmmm. I think like most shops, they are used to customers starting with the most HP they can buy but this is not your goal here. I get it. My previous auto-x/track car was a base model 1998 Integra. Not a Type-R, not a VTEC engine, but it was lighter and everything that wasn’t specifically engine related fit. It wasn’t very often that they were able to beat me. Now I have a base 981 for the same reason. It was significantly cheaper to get into a nice one, the chassis dynamics are the same, virtually everything fits, and I can build it into what I want. I wonder if it might be worth it to you to step up to a base 981 and use the money saved over an S to buy the Gold Leaf GT4 RS style intake. No affiliation, but it’s something I’d love to do someday if budget allows because aftermarket exhausts are illegal in my state and who cares if anyone else can hear my car when it sounds magnificent to me inside. GOLD LEAF - Porsche Performance Carbon Fiber Parts Specialist Performance and emotion enhancing lightweight manufacturer, focused on detailed craftsmanship solutions. Discover precision-engineered RS style carbon fiber air intakes for 981 and 718 Porsche Caymans. Enhance you car's performance and connect with your Cayman on an emotional level. goldleafperformance.com There is at least one 2.7L Cayman in England running this intake. Check out Renngineering on YouTube.

Honestly, 3.4 is barely adequate on a sports car in this day and age, when minivans usually have more

Yes when I talked to another another shop (Dundon) they suggested something similar, said it could be developed for the 987 with investment. The gold leaf product looks impressive.

Yes I know some think this way, it is in the back of my mind.