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A little more hp for R18

41624 Views 122 Replies 44 Participants Last post by  kwhiting1987
What mods can I do to get a little more power out of the civic ex with out making it a loud turd just looking for a little more pep

(This thread has been merged with two (for now) newer threads all dealing with getting more power from the R18 engine. New threads on this topic will be merged here. --Moderator)
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Why are people apparently very serious about getting significant horsepower gains from an R18? An R18 will outrun many v8 engined american made cars and trucks because they have either fuel or electronics shut offs before the r18 tops out. An r18 is the best economy car engine ever made. Why screw it up?
Why are people apparently very serious about getting significant horsepower gains from an R18? An R18 will outrun many v8 engined american made cars and trucks because they have either fuel or electronics shut offs before the r18 tops out. An r18 is the best economy car engine ever made. Why screw it up?
The R18 will not outrun most anything if the other driver puts their foot into it.

My wife's '18 Accord LX has the base 1.5 liter turbo and the CVT, and is a swift bastid. Acceleration is quite brisk - way better than my R18 with a 5MT.

The 10th gen Civic is available with the same drivetrain as the Accord. In a lighter car, it's got to be even more impressive.
i think he may have been being sarcastic in his remarks. just an observation/perception i took from it. however, i could be wrong, yet again!!!
The way I look at it the K24 is in no way superior to an R18. The gear box can only handle about 300 wheel torque. The engine is pretty much a high compression economy motor with variants making as little as 160hp.

2012 Si coupe is 2,887lbs
2012 EX coupe is 2,680lbs

IMO my R18 at 12psi with a 50 trim turbo weighing in under 2,600lbs after weight reduction, is pretty damn quick I've beaten many 335i's, Si's of all trims with/without mods, Challengers, WRX's, V6 accords, Range rovers, you name it whatever car is considered "Sporty" the performance is pretty much on par. It's also way more entertaining when you pull up to a stop light after, and they just stare at you demanding what type of got dang engine that thang got.

K24 you have to build it
R18 you have to build it

Just a turbo kit with supporting mods for an Si you're in over 7k without a tune. My custom kit with tuning, supporting mods, and some custom one off fabricated parts that no one else in the world has came in at $5,200.

If anyone is looking into a turbo R18 Greddy teamed up with RevHard and made a bolt on kit for 9th gen R18's. It still says TBA but I've seen come up for sale for around $4,200 for the complete kit.
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The way I look at it the K24 is in no way superior to an R18. The gear box can only handle about 300 wheel torque. The engine is pretty much a high compression economy motor with variants making as little as 160hp.

2012 Si coupe is 2,887lbs
2012 EX coupe is 2,680lbs

IMO my R18 at 12psi with a 50 trim turbo weighing in under 2,600lbs after weight reduction, is pretty damn quick I've beaten many 335i's, Si's of all trims with/without mods, Challengers, WRX's, V6 accords, Range rovers, you name it whatever car is considered "Sporty" the performance is pretty much on par. It's also way more entertaining when you pull up to a stop light after, and they just stare at you demanding what type of got dang engine that thang got.

K24 you have to build it
R18 you have to build it

Just a turbo kit with supporting mods for an Si you're in over 7k without a tune. My custom kit with tuning, supporting mods, and some custom one off fabricated parts that no one else in the world has came in at $5,200.

If anyone is looking into a turbo R18 Greddy teamed up with RevHard and made a bolt on kit for 9th gen R18's. It still says TBA but I've seen come up for sale for around $4,200 for the complete kit.


I cant imagine my car with a turbo lol
I saw a video on octane and it was basically saying that you won't notice any actual improvements if you go from 87 to 91...except for your wallet.
I saw a video on octane and it was basically saying that you won't notice any actual improvements if you go from 87 to 91...except for your wallet.
Please post a link. Silver2Coupe has been posting the virtues of 93 in an R18 for years with data to back it up - mostly mpg figures, though.
I drive my car in the city 99% of the time before 91 I got 23mpg after I got 24mpg, and better a mid range/throttle response and the car really didn't loose power after It got heat soaked like 87. With turbo and a really good tune from Steve at etunez I now still get exactly 24mpg with turbo. If you really get joy out of max mpg run 91, with a economy tune some people have seen 30mpg city with an Si. I only run Shell or Chevron while switching between the two between every 4 tanks, both brands use different detergents so why not get the best clean possible. Also my hondata was picking up 10-12 knock counts on 87! After I got it down to 1-2 knock counts on a really hot day with 91 octane with no ignition timing being pulled.
I am getting 40 plus mpg with premium in mix driving with my Honda HRV all wheel drive with a R18. I miss the Civic but had a ecu and battery issue with the 15 Civic. I traded it in on a Gen 10 coupe for my wife which she gets 36 mpg on regular it's a leased so not worried about reliability. Yes is different than the R18 but it does not have the reliability of the gen 9 civics.

My point of my post is the answer is in the question. You raise the compression by using premium gas. If premium gas is only good for a 7.5 compression motor in all load and rpm ranges then how detuned would it be in a 10.6 compression motor. I am no t saying premium raises power throughout the rpm but it raises power where you need it most. I have papers but will not post them. Someone gets mad and the link from the source disappears. It can be found easily if you look.

The R18 is econ motor which under no knock will use the 3 valve low cam from 1K to 3.5K also has a dual intake like the GSR famous intake the difference is between 20 to 30 percent in better mpg. I love the R18 and is why I bought the HRV. The HRV is rated from 26 city to 31 hwy. I am averaging 35 to now 40 mpg.

The ecu has to adjust and you have.to drive different. Usually the first tank is lower because its relearning and I call it a burn in break in. It's not going to make your car into a race car but its easier to drive and has the 10 hp you are looking for along with better mpg.
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Welcome to 9th gen.

One member that I know of here got noticeably better results using premium fuel in an R18. That, and a custom tune would be a good start, or rather, what I would do if I was so inclined.
Thanks for the advice. For everyone assuming that I am trying to squeeze out tons of power from this car, I am not.

I’d be receiving it completely paid off. I’m willing to spend in the neighborhood of $1500.

Can this car become comfortably faster? I think what I wanted to know is, what are the most sensible modifications one can make to give this car just a bit more.

Seems like the honest answer is : don’t mess with it. It’s good with a proper tune and you won’t get more noticeable power out of it. Use premium fuel. Possibly a cold air intake.

I was really looking for the smartest route in making subtly noticeable gains.
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I drive my car in the city 99% of the time before 91 I got 23mpg after I got 24mpg, and better a mid range/throttle response and the car really didn't loose power after It got heat soaked like 87. With turbo and a really good tune from Steve at etunez I now still get exactly 24mpg with turbo. If you really get joy out of max mpg run 91, with a economy tune some people have seen 30mpg city with an Si. I only run Shell or Chevron while switching between the two between every 4 tanks, both brands use different detergents so why not get the best clean possible. Also my hondata was picking up 10-12 knock counts on 87! After I got it down to 1-2 knock counts on a really hot day with 91 octane with no ignition timing being pulled.
You run 91 stock on the r18?
Why are people apparently very serious about getting significant horsepower gains from an R18? An R18 will outrun many v8 engined american made cars and trucks because they have either fuel or electronics shut offs before the r18 tops out. An r18 is the best economy car engine ever made. Why screw it up?
You think it is best in stock form for what it was built for?

Looking to squeeze out very conservative performance, not smoke V8s.
You can get more torque and mpg from premium. I have an HRV with awd now and after some experimenting I seen some big gains in mpg and performance. It has the R18 motor and after adding my ultragauge that monitors the ecu, I can say it adjusts and more torque and horsepower is at hand. I seen 150 hp on low econ cam at crossover. I also monitored the fuel trims and command air fuel. The ecu usually runs a command AF around 1.0 or lambda. When coming to a stop it goes to mbt 13.2 fuel air for 5 seconds then 14 7. Also at WOT it leans out to 12.5-12.7 AF from the stock command of 11 to 11.5 AF. I figure the HP is 25-30 off from the 140 HP Honda says. Fuel trims are close to zero.

Also I have no issues keeping up with high end sport cars. On regular I could not pass or get out of my way which is very dangerous on the tollway where people go way faster then the speed limits. All Honda cars are econ and the word econ means efficient. How can tune for more efficiency than the ecu is all ready set up for and adjusts by based on octane of the fuel. If you want to spend 30K on a motor to make the HP you want then you are better off buying a car made for HP. BTW 93 octane will support a 7.5 compression motor at all load ranges and rpms to redline. Which means it's running MBT timing throughout the rpm range with out fuel enrichment or egr. Now remember these motors are 10.6 to 11to1 so the octane requirements are higher which means there is a loss of efficiency and torque. Systems that allow lower octane are egr,low tension rings and oil being sprayed on the underside of the pistons.
Really great info.


So bottom line here is : use premium, keep it stock?

You seem to be very knowledgeable. I’m about to head over to the suspension forums, but was wondering if you knew anything about that.

I’m looking to replace the stock shocks for something possibly more dampening and comfortable. I’m at 120k miles.
Thanks for the advice. For everyone assuming that I am trying to squeeze out tons of power from this car, I am not.

I’d be receiving it completely paid off. I’m willing to spend in the neighborhood of $1500.

Can this car become comfortably faster? I think what I wanted to know is, what are the most sensible modifications one can make to give this car just a bit more.

Seems like the honest answer is : don’t mess with it. It’s good with a proper tune and you won’t get more noticeable power out of it. Use premium fuel. Possibly a cold air intake.

I was really looking for the smartest route in making subtly noticeable gains.
FWIW, I use K&N drop-ins on my cars and bikes that get a lot of use. It may flow a little more air, but with the restrictive airbox in the Civic it may not matter. I do like that I can clean and reuse it.

I had considered a CAI but rejected the idea as a waste of money for this car, but that's me.
You think it is best in stock form for what it was built for?

Looking to squeeze out very conservative performance, not smoke V8s.
Of course it is best in stock form for what it was built for. Maybe, just maybe, Honda knows how to design and build a car quite well for the purpose it was designed. That's part of the reason I own one. Let us know when you can legally get significant performance gains from an R18. A lot of people want to know. It's well known that higher octane gives some benefit for some people. What is "conservative performance" gains? I'd like to know how it can legally be done so I might be in a decision making mode. Me and a lot of other people. Illegal gains are illegal. That isn't a very popular thing to say in some places but hey, the law is the law and watch who supports breaking it either directly or indirectly anywhere you go.
You think it is best in stock form for what it was built for?

Looking to squeeze out very conservative performance, not smoke V8s.
Of course it is best in stock form for what it was built for. Maybe, just maybe, Honda knows how to design and build a car quite well for the purpose it was designed. That's part of the reason I own one. Let us know when you can legally get significant performance gains from an R18. A lot of people want to know. It's well known that higher octane gives some benefit for some people. What is "conservative performance" gains? I'd like to know how it can legally be done so I might be in a decision making mode. Me and a lot of other people. Illegal gains are illegal. That isn't a very popular thing to say in some places but hey, the law is the law and watch who supports breaking it either directly or indirectly anywhere you go.
Entirely legal gains. Nothing illegal. 15-20mph and some more torque would make me happy.

Looks like I’m just gonna use premium fuel and see where that goes, and put the money into the suspension.

It’s an 8 year old car. Was just hoping some tuning advancements would give this car a small boost of power.
Building on what Ridingaround wrote, Honda, and other manufacturers, have to walk a fine line between economy and performance (power).

With today's corporate average fuel economy requirements, every car in a company's lineup has a role to play. Some models favor high mileage over high performance, and some are opposite.

But even the most economical cars, in the North American market, anyway, can only offer a level of power that is just so low, or people won't buy it. Face it, we're kind of spoiled here.

Civic R18s are very well balanced. Decent power for most normal driving conditions, very good economy, and, to top it off, fantastic build quality, if the number of older Civics still on the roads is any indication. I see a lot of 10 to 15 year old Civics around here. My daughter has an '04 that starts right up and purrs like a kitten.

I am loathe to mess too much with such a car and enjoy it for what it is.
What I don't understand is why is there so much support and kits (Jackson Racing/Kraftwerks, GReddy, Full Race, etc) for the 8th gen r18s and not the 9th gens? What happened. Is it the fact that not enough people are interested yet because their cars haven't been paid off until now, or am I missing something? I for one am very interested, money is not an issue, nor do I want an Si. I would rather have a zippier car ~200whp/170wtq DD while drinking a coffee. The 9th gen R18s ATs have the same 5spd transmissions as the Acura RDXs, which have 240hp.

The term "waste" is relative. You see celebrities, executives, etc. waste money on Ferraris, Porsches, and god forbid, a G Wagon, which they will never use a 1/8th of their potential. I would call that more of a "waste" than me wanting a little more power out of my daily lol.
This thread has been stickied. New threads on this topic will be merged here.
Just a thought. Ik the r hasnt been around to to long now even still. Guys if we can max out d series motors i think we can find ways to max out a r series motor soon enough #save the single cams
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