Not much higher than stock, IMHO. It is an oversquare design which by nature limits it from screaming high rpms.

 

bent valve ftl

 

so does that mean 7500 rpm would be the limit or too high?

most street cars' engines are undersquare i thought (stroke is longer smaller bore) so they are more torquey as opposed to true race cars (F1) that rev to 17k rpm

anyways i just think that having a higher rev limit would allow me to stay closer to rpms where there is peak power...shifting into the super long 3rd gear the r18 has is annoying when you dont have much power

 

I'd guess Hondata wouldn't allow it to rev much past say 7.2ish. It just wont be making power that high up unless you have cams, better IM, but the header will limit flow regardless.

 

High rpms = fast movement of piston and valves

speed x weight = energy

high rpms beat up valvetrain which is why most cars don't rev high. I'd guess an extra 200-300 rpms would be near the top of the safety margin. Perhaps an extra 400 on very very limited use.

 

I doubt Engines are built like that... If your car has a 6,800rpm redline, that means the engine is designed to handle 7,000+ rpm's and the rev limit is lowered for increased durability.

Take the k20Z3 from the Si. It can handle 9,000rpm -/+ stock, without any damage, but at those speeds the engine wouldn't last very long, hence the rev limit is lowered to 8,000 so you can rev up there every day and not worry about piston rods flying through the hood.

A saw a youtube video of an R18 tuned with AEM revving to 7,500 rpm without problem. Looked and sounded very natural for the engine. It can handle it, no problem... how long is the question.

 

I'd say stay safe with the R18. Honda is already squeezing as much as they can out of the Tiny R18 that could. But there has been 2 incidents (mis-shift + lack of sleep ftw) where I bounced off the limiter at around 6.8k.

Flash Pro will most likely try to keep you in a safe range, if your daring go big. 10,000 RPM!!

 

:facepalm:

 

15,000 RPM? I mean it should be rather fun watching something go wrong..

 

ok so im thinking now that 7k redline would be good for me

 

I think our car can handle much more then 6800! You have to remember the R18 was tuned for gas saver, but at the same time, The R18 is a Honda engine! Stock motors is always under tuned, from the D-Series to the K-Series! Hondata always found hidden power! Don't be fooled by the gas saving car it is, tuning changes everything! And hondata can do it!

 

i sort of have to disagree...and i think many other knowledgable r18 owners will agree

the r18 is tuned pretty well from the factory...1.8 liter engine making more than 140hp (underrated from honda) while it is SOHC...yes it is tuned for saving gas but thats really only while it is in the econo vtec mode...other than that it is a solid engine it has more torque than the k20 and from my knowledge it is the most powerful NA SOHC 1.8 engine on the market

yes it can definitely be tuned to have more power but we wont get more power by having a higher redline unless you port and polish the head get new cams get a new intake manifold and somehow make the built in "header" flow better

 

whats the limiter at for a stock R18?

 

I would love to have a 10k rpm redline on my R18!

 

I hope ur kidding...

 

I'll be happy with 7500! get a little more hp with that.

 

the R18 has more torque than the K20?

I think we get roughly 130 ft lb of torque while the K20A gets around 150-160.

 

Okay most Knowledgable R18 owners should know si make 139tq at 6100rpm and the r18 make 128tq at 4300rpm!
When I said Honda is under tuned, I ment that hondata always finds a way to get more hp with just tuning! If you plan on getting the flashpro, you most likely will have some type of after market part in your car which will give you more hp when rising the redline! Like I said the R18 is tuned for Gas saver, which mean it's not tuned to it's full Potential power! Hondata wouldn't waste there time making a flashpro for our r18 if our cars was made it it's full potential!

 

reving high won't do anything for you if the cams aren't aggressive enough to make power up there.

just cuz you increase redline doesn't mean it will do anything for you. honda probably put pretty mild cams in there being as its an econobox so i doubt raising the rev limit to say 7500 would do much if anything at all.

 

You have to do the math breakdown to see if staying in X gear for another 500rpms is worth the actual power to the wheels verse shifting into the next gear.

Most of the time it's bet to run to redline to maximize the torque multiplication of that gear. But on cars that lack high end torque, it might be best to shift up in gears at the factory redline.


There are online calculators that allow you to plug in the cars gear and various torque ratings to allow you to see optimal shift RPMs. I'd look at thise before I'd risk damaging my car without any real gains./

 

ryker do you have a link to one of those calculators? or at least tell me what to search?

 

2 seconds on google ( calculate shift points)

Interactive Best Shift Points Program

sigh:

 

sub'd...

73/7400 would be fine for me

 

i will say this, a motor can only safely rev to higher rpms if the internals are built to do so. building a reliable high rpm engine takes allot of work. with the r series like most non-performance based honda motors, they are not intended to turn any higher rpm than the set red line. this is simple, why would honda build a motor for 8-10000 rpms then tune it back? in the non performance motors the stock internals are usually quite heavy and almost always un balanced. but hey if you want to blow up your stock motor go for it, i personally would wait to see if any one comes out with aftermarket pistons/rods and some valves/cams, before i rev my motor to the moon, and if these parts are never made available, then simply enjoy your bolt-ons and perhaps add a turbo kit, otherwise just enjoy your car either way, just don't expect it to perform miracles without being built properly.

 

^so you're saying the factory 6.8k rev limit on a civic is its MAX rev limit. Exceed that by a few hundred RPM and engine damage will occur? :facepalm:

Take the Si for example. With a redline @ 8k, factory fuel cut @ 8.2k you can rev it to 8.7k on stock internals and NOT sustain damage. I'm sure it could rev higher on stock internals but THAT would be pushing it.

Again, the motor is designed to handle 9k but detuned to a nice, safe 8k redline for DURABILITY!

Same can be said about every engine produced. If manufacturers were designing motors to spin to 7k before valve to piston contact occurs, they wouldn't set the redline @ 7k because the first time you bounce off the rev limiter, the engine is toast.

I bet when Hondata releases the FlashPro for the civic, their suggested "SAFE" rev limit would exceed 7,000 rpms.

 

^so you're saying the factory 6.8k rev limit on a civic is its MAX rev limit. Exceed that by a few hundred RPM and engine damage will occur? :facepalm:

Take the Si for example. With a redline @ 8k, factory fuel cut @ 8.2k you can rev it to 8.7k on stock internals and NOT sustain damage. I'm sure it could rev higher on stock internals but THAT would be pushing it.

Again, the motor is designed to handle 9k but detuned to a nice, safe 8k redline for DURABILITY!

Same can be said about every engine produced. If manufacturers were designing motors to spin to 7k before valve to piston contact occurs, they wouldn't set the redline @ 7k because the first time you bounce off the rev limiter, the engine is toast.


I bet when Hondata releases the FlashPro for the civic, their suggested "SAFE" rev limit would exceed 7,000 rpms.

yes the " r18" was designed to rev to the factory 6.8 not much beyond that. comparing the k series is apples to oranges as it was a motor that was designed and built with performance in mind, the r18 was not. and notice how i used words like reliability and safely. two words that go along ways to having a good reliable engine build. i suppose you might be one of those who believe that a b18b1 ls vtec swap is a simple as throwing a vtec head and all associated wiring then still hoping to turn 8-10000 rpms with it safely. :facepalm: as i said earlier, a motor hoping to turn higher rpms will only be as reliable as the internals that are used.

 

Dude, i agree with you. All im saying is that the R18 can easily spin to 7,500rpm. How long it will do so on stock internals is another question.

 

yea i mean 6800-7500 isnt much of a stretch, but i would like to see what gains you could get from that increase.

but hell id try it, i mean its not often you would rev your engine that high, i'll be getting flash pro over the coming months so ill see what gains i can come up with,

 

Im sure there will be no gain. From the Dyno's i've seen of R18, they stop making power past like 6.4ish RPM...

The members haven't mentioned anything about making power up there, just how high it can rev.

Making power is a whole other subject :thumb:

 

yes but what is the point of revving that high if there aren't any gains from it lol