Tomei Poncams Rb25/30de

[Brentmcd12]

Tomei Poncams

Part NO: 143020

AU $ 733.86

ECR33 Series 1 (RB25DET) - Duration: IN,EX 256 Lift: IN,EX 8.5mm

i have a 93rb25de... i will be making a RB30DE

the 30de will make enough torque so i want something that will give me midrange to topend...

this is from nengun..

Generally, engine tuning is to modify the torque characteristic of engine by changing cam duration timing and height of the cam lift, so as to gaining maximum torque and horse power. However, when tuning the engine strictly, it should be carried out with the idea of securing effective area of the valve not only by duration timing and height of the cam lift, but also by through improvement of its intake efficiency. High valve lift allows huge amount of air to flow in, yet it mechanically damages the system and gains friction loss. Also, wide cam duration will deriver great power at high RPM, but it gives rough engine character at low RPM too. Tomei have worked to get an ideal well-balanced profile of camshaft and succeeded to give it 1.3 to 1.5 times more effective area than regular camshafts

Tomei have been developing and producing their original camshafst ever since TOMEI established. Still today, they are providing high performance camshaft to many racing teams and winning lots of titles.

Type A

In order to get stable idle and raise low-mid RPM torque, we set the duration of EX camshaft shorter.

Best suit used with stock turbine or N1 turbine.

Type B

By giving longer duration timing than type a, it eables to raise both response and peak power at the same time, even with mid-large sized turbine.

WHAT ELSE IS THERE THAT I SHOULD GET IF THIS IS WRONG ??

[Eug]

haha, i looked at them before and they are tempting!

if you don't care for a lumpy idle then get the type b, that will give you your high rpm powerband.

look into cam shafts which will maintain vct, you may only need the exhaust cam gear only too

my personal advice

you'll need to break your modification down into stages.

at the moment you have your rb25, so you can work the head while keeping it 2.5L.

this should include:

• cam gears
  
• ecu
  
• port and polish
  
• oversized valves?
  
• upgraded valve and valve springs
  

they are the kind of mods you should do with the head off, and will make the most of the higher lift and longer duration.

drive it around for a year or so. this minimises the time you are off the road, and allows you to work on it progressively rather than all in one go.

then when you get more cash, take it completely apart and work on the 3L block.

[SKiT_R31]

If they are camshafts for tubo motors, they might not perform as well in a Naturally Asprirated motor, know the overlap details etc?

also, when do you want to make your power? this cam, "ECR33 Series 1 (RB25DET) - Duration: IN,EX 256 Lift: IN,EX 8.5mm" sounds great, pending the overlap question.

for example, my cam, is a surecam max regrind for the stock rb25 cams, its 255deg duration, 8.3mm lift

i got my power at 6000rpm and my torque at 5000rpm, with a few limitations, power drops off at ~ 6500, and by limiter is down about 10kw, after i fix a few issues im hoping it will atleast hold its power to ~ 7000rpm.

how far do you want to be revving it? the cam you've mentioned sounds good, but i probably wouldnt want to go any further for a daily, while mine has plenty down low, i wouldnt want any less, and to get into the torque/power of it, you need to sit above ~ 4k.

Also dont forget, once you start gonig bigger than a max regrind, your probably going to want to look at full aftermarket management....

edit: i also aggree with the above, not only for the fact of having it off the road for less time, but the fact of having it go quicker and quicker and quicker, the novelty's will last longer than getting it in one hit, that said, no point taking the same item off again and again... Obviously all headwork would be done at the same time, etc.

also, make sure you shave the head/block, i would have thaught 12:1 would be too far (would have to lose some timing?) but bringing mine from 10.4:1 to 11:1 made a MASSIVE difference, and i kept 15degs ignition, with 98ron no knocks.

Edited August 2, 2007 by SKiT_R31

[342Four]

11:1 and type b cam would equal a lumpy and snarling sounding car

by the looks of things, if you think that you will have enough low end with the 30, then go with type b

but if you do the mods like eug said, then i think you will be having to sacrifice some of the driveability, power etc with the 25 for a while (nothing lost, nothing gained they say...have to make sacrifices somewhere )

in regards to overlap, the r33 GTS and GTS-T cams are exactly the same, all thats different is the cam gears at the front - the turbo gears (i think!!) have a little more exhaust advance and more overlap, and the n/a gears have less overlap

[Brentmcd12]

cheers for the info guys...

im guessing after i press check out i can select wheather i want Type A or B on Nengun ? havent got that far yet

i will be usuing 25de pistons in the 30e so compression should be 10;5;1 ?

EUG..

i have exaust side cam gear... looking at getting intake side. as well... from bass junkey ?

i have a wolf 3d v3..

im not going to worry about a port and polish.. its just going to cost too much.. i asked about it n they said depends wat u want out of it... i just want bottom end torque with enough top end.. 7000rpm sorta thing yeh my rev limiter is 6200 :S

# oversized valves? - while ive got the head off do u reckon i should upgrade ? - i might go turbo in a few years...

# upgraded valve and valve springs - same as above...

im going to be doing everything at once... not worth wasting the money doing bits by bits...

just trying to find a mechanic that can help me mod the block and head to get it all to fit.. - re vct and - oil lines...

[Eug]

i think if you mess around with the intake cam gear you lose vct, or the adjustable gear becomes redundant as it's variable anyway.

better clear it up with nengun prior to purchase, they have been known to send wrong items before!

the idea behind upgrading a cam shaft is to increase lift and duration of the valves, saying that they are open bigger and for longer. oversizing the valves will make more use of that, as they are opening bigger again. this allows for more of the gases to be drawn in/expelled from the combustion chamber quicker.

port and polish, again, you have more gases going in and out, and making the head flow better will make the best use of that. think of it as an exhaust system, you're simply making it flow better and getting rid of restrictions. price it all up and compare it to an RB26 head, they flow better again.

speak with your mechanic, look into the quenching effects, thinnest head gasket possible, check for valve clearance, and skim as much as possible off the block and the head - whilst running on 98 RON.

if it's going turbo, then i wouldn't entirely be phased by port and polishing, valves etc. (they are done by hardcore turbo guys who are looking for the last 20-30kw), but in an NA situation you ideally want to get rid of as much restriction to the air/gas as possible.

hope that helps

[T04GTR]

b type had absolutly no losses down low on my 26. cool idle but. till i corected the injection end angle.

[Brentmcd12]

so even tho they are turbo cams they still work fine on the non turbo 25DE ?? - type b sounds good if they will work

my car is staying N/A

so i cant use adj intake side cam gear only the exaust side gear ?

also been looking at the

Trust - Greddy - Clear Cam Cover

To Suit RB26DETT engines

will fit with some modification anyone know ??

[dyken]

in regards to the clear cam cover, psi parts has custom ones for an rb25..

http://www.psiparts.com.au/front.asp?pid=14

hope that helps on that

[SKiT_R31]

you'll be lifting that rev limiter - definately, the funnest part of my car is between 4000rpma and 6500rpm and your cam is bigger again - the stock 6800rpm 25 limiter is pretty fair

with the 25 head, the 30 is a completely different motor, revving at 5-6k+ doesnt worry it at all, pulls hard all the way there, smooth as.

[GTS4WD]

Your going to definately want to port and polish, upgrade valves and springs

This may not have to be a very expensive ordeal.

If your mechanically minded and do the work urself a port and polish can easily be acheived with $20 worth of parts and a days work.

You could see if, for eg. there are different vales in the 30. You may be able to use those valves.. I do not know if they will mate (and yes I do know on is DOHC and 30's are SOHC).

As for springs.. use rb25DET springs.. their slightly stiffer rate and will do a good job of it.

According to the information given of both cams.. id strongly suggest type b.

And as said before.. make sure that ur aftermarket intake cam gear is NA and it will mate with the VCT. Its a great little system and not really worth throwing out yet..

diffinately increase the rev limiter. Once all the work will be done the engine will really jump alive from ~4500/5000 to at least 7000RPM.. get a good tuner to work on so as the VCT will compliment the new head work.

I dont think you should be worried about loosing too much power down low as the cam wont affect mid to low RPM and as its a 3L engine running ~11:1 CR you should have enough pull to get in you in the higher RPM where the head work will put you in the back of your seat..

any ideas on power fig?

Im really curious because Im really lookin forward to my NA build.

[GTS4WD]

Tomei Poncams

Part NO: 143020

AU $ 733.86

ECR33 Series 1 (RB25DET) - Duration: IN,EX 256 Lift: IN,EX 8.5mm

If the cams you are buying are for a DET then mate.. dont..

An NA engine LOVES to overlap! Its where alot of the power comes from!

The diff from NA and turbo cams is the overlap..

If you put overlapping cams in a turbo you throw out much of the boost out of the exhaust! Where as an NA uses the overlap to produce more power!

An idea is to get the stock cams regrounded!

Its cheap as!

Or you can go HARDCORE!

Ei:

Get oversized cams, port and polish, stiffer springs AND regrinde aftermarket NA cams! to like a spastic amound of lift and duration!

you will loose some down low torque.. BUT! if you up compression ratio in a 3L it will make up for that!

So.. you have a Hi comp 3L to give you lower down grunt, a lightened flywheel to get you into the higher RMP quicker.. and once your up there, let the cams do all the work!

Honestly.. I would not be surprised if with a bit of work.. an NA 25/30 would get 200KW.. if not more!

please someone do it!.. I just simply do not have the funds atm to be able to afford these mods!..

P.S I think I read somewhere that ur 25 head is VCT?.. Yes?.. if so.. dont get these cams.. you will loose your VCT.. Its not a MAJOR loss.. but its a little bit more that adds to the oomph.. Mind you have to run a few more oil lines etc. to get it working properly..

/end rant

Edited August 7, 2007 by GTS4WD

[Eug]

yeah, i'm a little 50/50 on the overlap. i've read so many people say that DET and DE are identical, and others have said otherwise.

best bet would be to compare the two for yourself, i'd like to have the final word on that too.

Cris: you won't lose the VCT.

tomei pon cam 256º with 8.5mm lift (intake and exhaust)

cam gears (the arospeed ones are dirt cheap anyway)

and i reckon you're laughing.

regardless of the overlap, the gains to be had from getting the cam shafts far outweigh the lack of overlap.

[Eug]

My recommendation;

Tomei Poncams 256 degrees inlet and exhaust for RB25DE (non neo)

Tomei Poncams 260 degrees inlet and exhaust for RB25DE (neo)

Any brand adjustable exhaust camshaft pulley at ~5 degrees retarded

Bass Junky inlet cam adjusters at ~ 3 degrees advanced.

Set the camshaft timing on the dyno.

biggrin.gif cheers biggrin.gif

there we go

[Brentmcd12]

i pmd bass juny for a intake cam gear but he hasnt replied

[Eug]

the arospeed ones are dirt cheap... cant pass them up

[Brentmcd12]

well i just need the intake side..

do u have a link or where to buy ?

im still confused over the turbo and non turbo issue..

i havent decided if i should get harder valves n springs...

because it will be N/A but will this make it rev harder?

[Eug]

http://www.skylinesaustralia.com/forums/in...howtopic=173549

valve springs wont really make it rev harder. cheapest upgrade would be DET valves + springs.

the stronger springs means that the valves move in and out of the cylinder head more directly, quicker? and firmly, and not as "lazy".

also with bumped up compression it's a little more ideal.

why are you doing the intake cam gear? just retard the exhaust

[SKiT_R31]

im pretty sure i heard somewhere that thr cams on n/a and turbo are the same, but the gears are adjusted accordingly for overlap?

overlap pretty much works so that as the exhaust is blowing out, it sucks a/f in.

i fully agree with the statement that one could make 200rwkw, i think it could easily, and if the right money is spent, in the right places, the car could be VERY drivable, happily.

and damn that would feel good mmm, i love the 30de

[Brentmcd12]

why are you doing the intake cam gear? just retard the exhaust

so i DONT need the intake cam gear then ?

ill have to find some valve springs to buy from somewhere if u guys think its worthwile...

im still unsure about port n polish because to get a place to do it will cost a fair bit extra.