[DC5R] Valve Springs

[Tiu]

After running the mugen n1 ecu for about a month n abit now

I'm looking in upgrading my stock valve springs because it recommends to change valve spring to use with the ecu. At the moment, i'm got a few in mind, JUN, Spoon, Mugen and Toda. Do valve springs have different specs? or do they all do the same job and able to support the engine to rev to 9200rpm safely?

I'm planning to get cams later on as well, is it better to stick with the same brand with the valve springs? What is a good set of cams to look at?

[mikoZ]

ips ＋ jdm type r valvetrain

[fatboyz39]

Might as well do cams and valve springs same time. In the meantime just rev it to 8400 rpm.

[Tiu]

Might as well do cams and valve springs same time. In the meantime just rev it to 8400 rpm.

yah, because i'm overseas at the moment. Planning to just buy it here but don't know which brand to go with. Should the valve springs match the cams? or any aftermarket valve springs will do?

[air23box]

stick with mugen....they made it for the ecu anywayz......dunno about other brands' spec anywayz.....dun forget head gasket too....they are not expensive....

[fatboyz39]

yah, because i'm overseas at the moment. Planning to just buy it here but don't know which brand to go with. Should the valve springs match the cams? or any aftermarket valve springs will do?

Depending what cams your going for. I guess since your in japan then i would say try toda or JUN.

[mugsee]

Might as well do cams and valve springs same time. In the meantime just rev it to 8400 rpm.

I second this suggestion.

Power starts to dip down above 8400 on the K20A2 and there isn't much to be gained by revving it more. *glances at mugenbox*

[szymonsta]

i have mugen n1 ecu on my dc2r and was also looking to replace valvesprings with mugen ones, as recommended by mugen - same as you.

this is what i came up with:

*there is quite abit of work involved with replacing valvesprings, i dont have the time or mechanical experience to do this myslef, so i got a few quotes and it was around the $2000 mark just for labour !!!

*for such an expense, while you're there, you might as well change the cams at the same time as replacing the cam gears, in which xase you should get valvesprings suited to your cams, ie not mugen ones which are designed for the stock cams. i'd get the same brand valvesprings as cams, like jun, toda, spoon, etc.

*with the aftermarket cams and valvesprings in, u might as well get adjustable cam sprockets for fine-tuning, since you've now spent a lot on getting this far..possibly a thinner head gasket too, to increase compression slightly..

*with this combination, your mugen n1 ecu is less than ideal, since as we all know its not programmable, so you'd need a replacement ecu such as apexi power fc or hondata or the like..

summarising, this is a fairly substantial job, requiring a fair bit of $ to 'do the job properly'. my decision was to not go ahead, and simply dont rev the car right to the higher mugen limmiter..not an ideal solution, but one that works for me.

[Tiu]

good analysis.

Is it harder to change valve springs in a b series than k series motor? because i got a quote before from toda au for about $5xx-$600.

I was thinking of doing the cams and springs at the same time but don't know which one to go for. JUN? TODA? Does VTC = ivtec? will it be less street friendly without ivtec?

I never thought about change the ecu as i'm really happy with the mugen n1, it's damn good. Just want to get a bit more out of it? Maybe use jdm itr cams?

i have mugen n1 ecu on my dc2r and was also looking to replace valvesprings with mugen ones, as recommended by mugen - same as you.

this is what i came up with:

*there is quite abit of work involved with replacing valvesprings, i dont have the time or mechanical experience to do this myslef, so i got a few quotes and it was around the $2000 mark just for labour !!!

*for such an expense, while you're there, you might as well change the cams at the same time as replacing the cam gears, in which xase you should get valvesprings suited to your cams, ie not mugen ones which are designed for the stock cams. i'd get the same brand valvesprings as cams, like jun, toda, spoon, etc.

*with the aftermarket cams and valvesprings in, u might as well get adjustable cam sprockets for fine-tuning, since you've now spent a lot on getting this far..possibly a thinner head gasket too, to increase compression slightly..

*with this combination, your mugen n1 ecu is less than ideal, since as we all know its not programmable, so you'd need a replacement ecu such as apexi power fc or hondata or the like..

summarising, this is a fairly substantial job, requiring a fair bit of $ to 'do the job properly'. my decision was to not go ahead, and simply dont rev the car right to the higher mugen limmiter..not an ideal solution, but one that works for me.

Does mugen make cams at all? Because i would love to match the springs n cams.

stick with mugen....they made it for the ecu anywayz......dunno about other brands' spec anywayz.....dun forget head gasket too....they are not expensive....

[air23box]

mugen ECU can run with A2 cams.....

[szymonsta]

mugen do not make any engine internals other than head gasket and valvesprings (for road use anyway)..
they do have machining facilities but i beleive they only make internals and complete engines for race use (go kart, formula racers, etc) which arent available for road users..dunno, maybe if u have 'special powers' like jingers u can get that stuff, like his mugen n1 racing exhaust system (the LOUD one, not the twin loop)..but its not available for public sale.

my amateur opinion is:
i think if u are going to the trouble of changing cams, replacing with standard jdm itr cams will be kind of pointless as the difference will be very small, u may as well go something a bit more aggressive so that u can notice a signifficant improvement in power.
obviously you probably dont want to get the cams with the most aggressive cam profile, like the toda VTEC-less cams, as these would require signifficant further modifications to work optimally (ie close gearing, probably quad throttles, internals..)
but perhaps a mild to medium cam upgrade would be good, which retains daily-driveability and doesnt require revving much higher than standard for the optimum power..JUN and TODA make several cams of various duration and lift, i'd speak to someone who has experience in doing this as i am just sharing my opinions and have no experience with this
either way i think the mugen n1 ecu you have will not be optimum for such as setup, as it is designed to work with the standard jdm itr cams and is non-programmable..i guess it may still work well with the mild upgrade, but my opinion is that anything much more aggressive than stock and it will not be an optimum tune..my 2c and please talk to someone who actually knows what they are doing before doing anything

[noodleman]

is it really worth all that trouble to rev the extra 800rpm??? will you get gain from that 800 rpm?

[mugsee]

is it really worth all that trouble to rev the extra 800rpm??? will you get gain from that 800 rpm?

Women... they love the noise.

Ask Mugenbox and his 9200rpm's.

[noodleman]

mine can go to 9200...but the curve is flat after 8800....dont see the point to rev that high except for the sound it makes

[mugsee]

dont see the point to rev that high except for the sound it makes

...exactly