Opinions on Rev limit Built B18C

[ijwhiteman]

Ok cool, i'v never come across anyone with them so i'll take your word for it on them been a midrange cam.

Make sure you mention your exhaust setup to them, if you know measurements of your header/exhaust then let them know what they are as these will be quite important.

Good luck with it by the way and i hope it works out well for you. Let us know how you get on.

Rich

I will do thanks. They also are top end aswell... 12.5mm lift on VTEC. We will just see how they feel. I'm sure it'll be great!

 

[ijwhiteman]

Some more info i found

"Int-295 dur. / 12.5mm lift
Exh-295 dur. / 12.5mm lift
Valve Springs to be used: Toda
Description: The ultimate cam. This cam mixes the midrange power of the Toda B cam with the top end of similar to that of the JUN Type 3 and Skunk2 Stage 2. Power gains from 4500rpms all the way to 9000rpms. This is truly, the best overall cam for both midrange and top-end power. They might not give the top-end gains of the Skunk2 Stage 3 but you get more midrange and these cams can be used on the street with the right set-up and the deep pocketbook. Due to the crazy off-VTEC lobes the idle is rougher than stock, just like the Toda B cam.

I have used both Jun 3 and Toda C on my B18C with ported B16A heads.

Jun 3 - Low to mid-range not fantastic. My vtec crossover point is at 4800rpm. After vtec switch over, the cam will suddenly pull real hard from about 6000rpm all the way to 9000rpm. Throttle respond from 6k to 9k rpm are awesome. I think if set properly on a B16 engine it will pull all the way to 9.5k to 10k no problem, coz on my B18C, the dyno graph showed that peak power was like at 8950rpm, and it was not dropping yet but lift throttle off at 9100rpm already. Idling also a bit problem but still not too rough on slow speed.

Toda C - Compared with Jun 3, it had better low to mid range power, i think due to the higher duration on the smaller lobe. I found it more difficult to set the cams and the idling was a bitch.. difficult to drive daily on street use.. At vtec cross over point, the power delivery is much smoother and it still pulls comfortably to 9k rpms. But it lacked the sudden surge like the Jun 3 at 6k to 9k.

For outright top end power, I feel Jun3 is better than Toda C. But Low to mid rev i feel toda C better."

 

[Rich777]

My Jun3 crossover was at 7200 if i remember correctly. Anything under this and there was just a dip in power. The idle was really good to, i couldn't fault them until the intake cam snapped.

 

[ijwhiteman]

My Jun3 crossover was at 7200 if i remember correctly. Anything under this and there was just a dip in power. The idle was really good to, i couldn't fault them until the intake cam snapped.

Yours aswell? Found a few people saying jun3 cams snap.... Fcuk that!

 

[Rich777]

Yeh, i was so so so pissed off. I showed the broken cam to my uncle thats and engineer and he told me it was a casting fault. You wouldn't belive the way Nengun treated me when it come to replacing the cam.

 

[olly ek9]

glad to see companies like Toda taking honda cam design seriously and spending time on the primary cam lobes, so many otehr cams only concentrate on the vtec side, hondas need help in the midrange more than anywhere else,, Good cam choice Ian,

As for yoru rev limit providing their not suggesting something thats insaneley high i woudl go with what your tuner reccomends,
its all going to come down to the tune and where you can still hold power to aswell as teh engine components used.

I think its worth having a couple hunred rpm past peak so that when your on track you can hold a gear a bit when going round a corner so you can straighten up and shift as oppose to banging off the rev limiter half way round, if your corner entry determines that you are in between gears, although with a decent bmidrange gain you will most probably be a gear higher everywhere so not so much of a problem.

With your FD and expected gains in midrange power i woudl of thought 9100 rpm would be more than enough, also seems a nice number, spoon must of done more research than most and thats where they set their ecu's at,,, food for thought

 

[elchunk]

since this car is the spoon civic of the forum i feel it should rev as high as the original around 11,000rpm! but i'd go with 9100 as without going crazy on the head it would probably loose power / struggle to make power after that rev limit anyway.. Sounds like its going to be awesome man cant wait!

 

[Kozy]

since this car is the spoon civic of the forum i feel it should rev as high as the original around 11,000rpm!

They needed that uber expensive block brace to rev that high though!

I couldn't estimate a rev limit for a particular build as I think it is impossible without being the tuner in question, but from what I understand the piston 'running away' from the flame front could be a limiting factor at high speed in a B18, something which is slightly less of a problem in a B16B. I have no idea how fast you'd need to be running for this to actually be a problem, but a B18C is definately going to hit this limit before a B16B and having high dome pistons will only serve to make the problem worse as they can act to slow down the burn. If this is the case, then I can't see any cam improving the situation.

ETA: Here's a little graph representing calculated piston speeds of a B16B at 9k and a B18C at 8k.

We can see even with the B16B spinning 1k faster, the piston speed is still slightly slower than the B18C. This tells me that wherever this 'wall' is, the point where the piston travels down the bore faster than the flame front, will happen approximately 1000rpm earlier in a B18C.

In conclusion, I have absolutely no idea what speed you should set you limiter at, so all this was pretty pointless.

[/nerd]

 

[Vtec6000]

They needed that uber expensive block brace to rev that high though!

I couldn't estimate a rev limit for a particular build as I think it is impossible without being the tuner in question, but from what I understand the piston 'running away' from the flame front could be a limiting factor at high speed in a B18, something which is slightly less of a problem in a B16B. I have no idea how fast you'd need to be running for this to actually be a problem, but a B18C is definately going to hit this limit before a B16B and having high dome pistons will only serve to make the problem worse as they can act to slow down the burn. If this is the case, then I can't see any cam improving the situation.

I could be talking complete rubbish though!

Its a good point but I can't see the ignition system been that restricted where you couldn't advance it enough to get the peak pressure caused by the combustion where it needs to be although i'm yet to need push a engine to 10,000rpm
And certainly the shorter stroke engine will be happier to rev higher

 

[olly ek9]

some real interesting conciderations there Kozy

 

[ramboteamjon]

Wow a was with you all till the last few posts!! lol all cool and interesting thoughts, idea, etc tho! Ian your car is gona be sweet!

 

[Gunter]

Is the spoon brace really needed to rev to 10k? i figured it only reduced vibrations to help it make power at high rpm rather than damage

and the toda cams were used in the uk's fastest nasp fwd honda (b20 crx) they made 260bhp on that so can only do good things for you, youd have to ask daz for exact details but they may have made power up to the 10.5k limit he had

are you using a 1998 spec integra box or custom box as i found the ratios are all over the place

 

[KieranEG6]

Is the spoon brace really needed to rev to 10k? i figured it only reduced vibrations to help it make power at high rpm rather than damage

and the toda cams were used in the uk's fastest nasp fwd honda (b20 crx) they made 260bhp on that so can only do good things for you, youd have to ask daz for exact details but they may have made power up to the 10.5k limit he had

are you using a 1998 spec integra box or custom box as i found the ratios are all over the place

YouTube - Spoon 10,000 rpm engine

Looks like plenty of damage to me

10.5K rev limit???? are you sure???

Daz's crx had a rev limit of 8800, its in his build thread on hondacrx.co.uk
""rev limit is still 8800. i took the car to 9k once and the extra gained in that 200rpm wasnt worth the extra strain imho.""

 

[Wazer]

Surely when dyno'd, you'll see when the power starts to drop and should be around that area give or take a few hundred rpm. Not much point in revving it further, when its already creating less power/torque and like other people have stated putting more strain on the engine.

 

[ijwhiteman]

Thank you all for your input. My tuner recommends 8600-8800 for outright reliability. I've asked for 9100 but he tells me he will not tune over 9000rpm. I'm happy with the decision and it will only go that high on occasions where I need to hold a gear. And one thing to also mention that is a true 9k where as I will be shifting at tacho 9k which is more like 8700rpm.

Once again thanks all

 

[olly ek9]

I'd just go with what will reccomends, he's not gonna warrant an engine if you decide for it to be revved higher than he reccommends

 

[ijwhiteman]

I'd just go with what will reccomends, he's not gonna warrant an engine if you decide for it to be revved higher than he reccommends

He agree that as long as it isn't reved to that all the time it'll be fine. His only concern is that it would need the rings changed after 50k miles well that is 10 years driving for me. I won't have this car for 10 years

 

[haitch]

Thank you all for your input. My tuner recommends 8600-8800 for outright reliability. I've asked for 9100 but he tells me he will not tune over 9000rpm. I'm happy with the decision and it will only go that high on occasions where I need to hold a gear. And one thing to also mention that is a true 9k where as I will be shifting at tacho 9k which is more like 8700rpm.

Once again thanks all

Sounds good, should have plenty of torque with your build, no need to rev the t*ts off it, mines 8600. Whats the latest!

 

[Junezslick]

cousin once took his to 10k on Bone Stock gsr internals in his ek just with a chipped ecu.. no joke that scared the shi outa me! thought he was going to blow the thing up

 

[Tsuchinoko]

IMO 9k