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Hey all,

Let me start by letting y'all know that I have been readingthrough this and other forums, manuals, writeups, etc regarding the topic of "how to make a 7gen civic more powerful" before this point. A lot of great discussion, and I'm aware of limitations on the D17 and this chassis as a whole. Granted, I’m no expert and would like to hear some opinions. It seems well agreed upon that trying to make any power past 200hp with a turbo on a D17 has quickly diminishing returns, and anything past stock power on an NA engine isn’t going to happen without a serious fight. And yes, I know a K-swap is always going to make power way easier, and I could sell my car and use the money I would have used modifying it to buy something way faster out the gate.

Okay, now that’s out of the way here’s the situation: I have a 2002 em2 ex 5sp, it’s my daily driver, and my engine is old and leaky after 270k miles. Nothing catastrophic, but given our engine’s reputation for blowing gaskets, I’d like to do something about the whole situation. K-swaps are awesome and I’d be open to it, but after an engine, transmission, harnesses, mounts, etc etc it’s out of my budget, plus the car would be out of commission much longer while the nitty gritty is hammered out. If I wasn’t as fun and silly as I am, I could also get a different car. But I already have invested a good chunk of time, money, and love into maintenance, chassis and suspension, and aesthetics (I love my little shitbox).

So, I’m going to stick with the ole D17 for the foreseeable future. I’d like to give it a rebuild, but I’ve been throwing around a lot of “well, since I’m already in there” ideas. If it makes sense, I’d like to make between 140-170whp (thereabouts the power of a stock Si of the same generation). Nothing serious, I’m not looking to be fast in a straight line at all. Just a bit more grunt from the engine would be nice. ADDITIONALLY, I’m considering getting another D17a2 that I can rebuild/modify on a stand, so in that respect I won’t be out of a car for terribly long whil e I’m doing engine work (minus the swap process). So, here are the routes I’m considering and the pros and cons of each:

Route 1: High compression pistons. I figure by raising compression a moderate amount (10.5-11.5:1?), P&P ing the head, CAI, exhaust, and maybe a fuel controller (I hear some folks have used an Apexi VAFC II on our stock ECU’s, anyone know anything more about this? lmk), I could pick up a couple ponies. I already have the I&E, and when I havethe head off I’m going to P&P regardless so it wouldn’t be a terrible leap to accomplish this.

Pros:

• Minimal fabrication/modifications needed (as far as I can see)
  
• Along with engine rebuild, my goal compression ratio should be fairly gentle on the engine
  
• Few unknowns to the process of replacing pistons – well documented in manuals, forums, etc.
  
• Cheapest option, assuming I don’t need a standalone ECU and pistons don’t cost an obscene amount.
  

Cons:

• Harder to find high comp pistons than low comp pistons (for turbo applications)
  
  • I’ve heard some talk about putting pistons from either a D17a7 or one of the D16’s, anyone have any input? The a7 pistons are from the GX and have 12.5:1 comp if I recall, so that might be a little too high.
    
• Probably need to run higher octane fuel.
  
  • If it’s <91, I’m cool with that.
    
• May fall short even of my modest power goals.
  
  • If so, are there any additional supporting mods that would help the pistons make more power?
    
• AFR tuning is difficult on our platform without getting a standalone ECU, and I’m not trying to drop $1000 on a computer for my car atm.
  
  • Again I’ve heard of Apexi’s VAFC II and a few other fuel controllers (PnPDuino? https://pnpduino.com/product/honda-d17) , but I’m aware they’re not as great as a standalone and therefore will be rougher for engine longevity.
    
• Extra strain on the wimpy D17 rods.
  

Route 2: Cam upgrade. Ahh, the search for the fabled Crower Stage I D17a2 camshaft. While this would be nice to find used or something, they seem quite difficult to come by in the year of our Lord 2025, so I’ve been throwing around the idea of doing a D16 3-lobe VTEC valve train swap. Not just an oem one either – swapping the valve train IN ORDER TO fit a Crower (maybe Skunk2? Opinions?) D16 cam, which I see they still produce. In particular, I’d be following this process for the valve train swap: Pirategarage has done some cool work with the D17, Red is a legend for exploding these engines. But do we think this will work? In theory if you have the correct rocker assembly and do the modifications to the cam gear Red does on his stock D16Y8 cam, then it should fit and be a more noticeable jump than just going to the stock D16 cam, right? Especially combined with the I,E,P&P and some RSX injectors I scooped in case I went turbo in the future.

Pros:

• A stage I cam should be less stressful on the engine than high comp pistons or a turbo in terms of engine longevity.
  
• Cam + 3-lobe VTEC + I,E,P&P + RSX injectors + a fuel controller(?) has got to produce a good bump in power, even on our little engines. Since I already have some of these things, I’d really need to get the rocker assembly/D16Y8 head, cam gear, cam, and fuel controller to make this setup happen.
  
• Less complex than a turbo setup, after all is said and done.
  

Cons:

• More expensive than the high comp pistons, more parts needed to make it work.
  
• Fab/part modification required, higher chance for things to get botched.
  

Route 3: Turbo. Here it is folks: to turbo, or not to turbo? This would make the most power, hands down. If I were to go this route, I would likely try to source a junkyard turbo in good shape from an oem turbo car (things with a small Ecoboost engine, Beetles, Jettas, etc), a maxpeedingrods intake manifold, a used or maxpeedingrods intercooler and piping, aem fittings for lines, maybe some kind of oil intercooler from another junkyard car, a D16Y8 intake manifold, the RSX injectors I have laying around, and whatever else I could source would likely be cheap. If I COULD avoid getting an entire standalone ECU I would, but I would also attempt to find this second hand. If not, I’d go for a piggyback (hey, I’m not made of money). My goal would be a very modest 5-8psi of boost, so I’d hope this would be a small enough amount to get by with a piggyback/fuel controller or something. I’m leaning away from this option, because it is the most expensive to do correctly and safely for a daily driver. I could wait longer, save up, and buy the correct componentry, but this means potentially waiting until the engine in my car gives up on me, as well as spending as much as a cheap junkyard K-swap. It’d be p sick though.

Pros:

• Would almost certainly make the most power of all these setups.
  
• Leaves room for additional upgrades in the future.
  
  • Although, I wouldn’t be far away from the max amount of power I’d be willing to invest money into with the D17.
    
• Well documented and explored route for modification – any questions could be answered in the forums.
  

Cons:

• Most expensive route, realistically outside of my budget currently to do properly.
  
  • Longer time frame means I could potentially break the process into smaller pieces instead of trying to buy all the parts and do all of it at once.
    
• Longer overall process means it could potentially put me out of my car for the longest amount of time, if I decide to rebuild the engine in the car rather than rebuild a different one.
  
• Because I’m keeping this project below the cost of a k-swap and the cost range that means, I’m concerned about reliability. This is my daily driver, and I know that cutting costs in a turbo setup is usually at the cost of reliability.
  
  • How reliably can one turbo a civic for < around $1000? Where does this mean saving money, and where does this mean spending it? Specifically, can one make a healthy, mild turbo build only using a piggyback/AFC?
    

If none of these routes make any sense in terms of 1. making at least 140whp, 2. being reliable, 3. cost, and 4. being a feasible modification to perform, then I suppose I’ll have to accept that the D17 is indeed the most unmodifiable engine ever created and I should just do a stock rebuild without trying to squeeze any more power out. But any time I see posts shooting a D17 build down, the poster is always aiming for like 200+hp from bolt ons alone rather than the very mild goals I have.

This post isn’t necessarily a specific question, but more just reaching out for collective knowledge. If anyone has anything to add, it will be helpful in deciding which route I go down. Additionally, it’s just nice to have all my thoughts on the topic written somewhere.

Thanks!

 
Rep Power: 125

I'm gonna stop you right there.

A half decent T3 by itself will easily be half your budget. The software and tuning will easily be the other half. That doesn't include your cooling, potential changes to the fuel system, any modifications to the exhaust (including the manifold the turbo should mount to), intake piping, etc. $1000 gets you about 1/4 of the way to what I'd consider potentially reliable.

You can get mega cheap parts and try to tune yourself but I'd be surprised if it lasts a week. It's a recipe for disaster.

The other option is to source used parts off junked turbo cars (1.8t's and whatnot) and sort of makeshift the rest of it together, but even then you're looking bare minimum $2500 to get it done decently. $1000 just isn't realistic at all.

Not even worth discussing the NA route.

Edit: Holy crap, even the eBay kits are like $800USD shipped now. You don't stand a chance lol

 
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Yeah, the turbo route is the one I'm least interested in almost entirely for those reasons. IF I were to go that route, I'd be sourcing used/junkyard stuff for almost all of it where I could, but between getting quality parts, getting it set up correctly, tuning it, etc I get what you're saying.

I'm still unconvinced about the NA route. I know, the rods are toothpicks, the heads don't flow at all, head gaskets are blowing in the wind, no one makes a cam for the D17, it's an economy engine, etc etc etc. These are all valid points, and I know they're enough to close the argument for anyone who wants their civic to actually go fast. However I don't really want a fast civic, just a faster one. If you cam'd or bumped up compression on ANY other engine, it would increase power. Between an intake, exhaust, cam, fuel injectors, head P&P, and some flavor of fuel management (https://pnpduino.com/product/honda-d17/ looks promising), you'd HAVE to make at least SOME additional power. Especially after seeing this dude's Dyno results: https://www.7thgenhonda.com/threads/...oldest#replies (125whp with an I,C&E).

Also FRSam sick CX650TC, I've been obsessed with these ever since RCR did a review on one. If I end up actually saving up to turbo the civic you better believe I'm putting 100 turbo badges all over that sucker.

 
Rep Power: 125

I don’t think you’ll be able to cam it for under $1000. I don’t know the market for cams anymore but you still need the software and tuning which is going to be most of your budget, not to mention the supporting mods of running your engine harder. Based on what you’ve described, I don’t think you’ve got much engine left as it is.

The TC’s a cool bike. It’s a bit of a resto project at the moment that I haven’t touched in a while but I’ll get around to it eventually. Just have other stuff on the go.

 
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Even with a cam, you need Kpro, an AEM timing gear and upgraded valve springs and retainers to start.
Go check out my build thread for a "cheap" turbo build. The t3 kit was the cheapest part of the whole build.

If you're dead set on an NA car, just buy the OEM GX pistons of your year, which are like 12.5:1.

 
Rep Power: 511

ngl, a cammed/boosted D17 was fun as hell. Still made 30+ MPG when I didn't abuse it, but I definitely had it burn a quarter tank of gas in 50 miles when I did. The turbo I had in my EM2 had a problem with the wastegate actuator, so it only gave me like 3psi, but it still made 155whp after all was said and done (from a stock, what, 110?). Stock engine with upgraded injectors, the D17 can handle up to 8psi (10 if you have a really good tuner). Back in the mid-late 00s, it did cost me like $3k for the turbo kit, cam, and tuning. Had a T3 super 60, and I already had supporting mods going into it. Sad I had to get rid of that car after a catastrophic head gasket failure and failed repair, but I moved up to a 2018 Civic hatch after that, and it currently makes 215whp and 245ft-lbs torque. Before you ask, I offloaded my Crower Stage 1 D17 cam like 7 years ago.

Back on point, Sam is pretty much on point though. You can probably find a used T3 super 60 for $500, tuning, $250 at a minimum, not including the tuning platform, which could easily be $250-1200 alone (cheapest used piggyback on the low end, donor k-series ECU with kpro on the high), depending on how you go. $100 for RSX-S injectors (used) which have enough flow to keep up with a fair amount of boost. Lord knows how much the fab is going to cost.

If you up your budget to say, $2k, and willing to do a lot of the work yourself, you can get good, safe boost or a K20A3 swap, and that's if you shop frugal af

 
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I see what you mean, looks like most cams for the D16Y8 are running around $400-$600 shipped, not to mention the cost of the D16 rocker assembly (found one @ $300 on ebay) and the cam gear (idk, $200?) to make it fit the 17. Maybe that could be something I do one step at a time; stock D16 stuff first, make sure it works correctly, then try sticking a cam in later. Something I’m not terribly worried about is the tuning: I wouldn’t. I know I know it’s always better for longevity and performance but for both the Crower and Blox cams they don’t even mention tuning until stage 3 stuff, and that’s not where I’m going with this.

Not sure why I decided to calculate it like this, but that $1000 number I referred to doesn’t include the things I would consider the “base rebuild” of the engine (head gasket, timing belt, water pump, head studs, piston rings, rod cap bolts, main bearings, etc). The rebuild portion is the primary objective here, and any kind of other goofy **** I get into along the way is secondary haha. That 1000 (a number I’m not tied to in any way, just threw it out there as a placeholder) is to see if I could squeeze a little extra out while I’m in there, you know?

T he engine isn’t original, so I’m going to make the safe assumption that it has less than the 270k on the chassis. It idles great, doesn’t burn oil, revs and runs very happily, and will take entire days of thrashing on twisty roads. The plugs always look good, oil changes have been quite clean, yadda yadda.

I figure if I can spend $600 on all the gaskets, rings, studs and the like, I’ll have an even healthier little engine for my shitbox daily that I plan on doing some autocrossing in next year. Since the frame and body is pretty rust free and all my suspension arms, bushings, tires, brakes, and struts are new the engine is the only thing I am preemptively worried about at this point. If there’s a way to get just a little extra punch out of the damn thing without spending the cost of another 2002 honda civic on it, I’m interested in learning more.

Does the turbo powerband on the CX actually make it weird in corners? I suppose it would only be something to consider as you’re coming back on throttle out, huh?

 
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D16 cam is WAY more work. Snout diameter is different so you gotta figure out the cam gear situation. There's a reason people don't regularly mix n' match d16 parts on a d17 platform car. Too many differences.

 
Rep Power: 125

This is ultimately where you're going to run into issues.

The shaft drive is what causes issues in the corners. The combination of it and then sudden input from the turbo causes the bike to want to sit up straight, and then you fighting it back down makes the back wheel want to lift up off the ground. It's fun once you get the hang of it but terrifying until then.