Rb25de Dream Engine

[Hella Flush]

no words required...

Edited January 6, 2007 by Hella Flush

[Eug]

its actually an RB25, but yes it's pretty horny

[funkymonkey]

damn... someone did to the RB25 what I wanted to do to my RB20DE GTS.

[Traditimeour]

where do i place my order?

[Eug]

alright let's get this discussion underway.

ITB throttle bodies + custom adapter plate + custom trumpets.

pros?

- increased power

- increased response

- the sound!

- watching the butterflies open and close

cons?

- cost. i have no idea, but judging by the costs of rb26 throttle bodies, and the cost of relocating a few things, custom bits and pieces (1-1.5k ??).

- r&d required for tuned length intake runners (adjustable runners?) narrow power band.

some other things to bring up:

- cheaper to use RB26 throttles or buy some pre-fabricated ones?

- legalities?

- adapt small pod filters onto the end of each.

- anyone who is (knows of someone) who is cluey with ITBs? mainly hondas, mini, porsche, and old school nissan owners with some know how.

[Hella Flush]

a good question is... who makes a direct fit kit for ITB's for rb20/rb25?

*starts looking*

[D-limo]

First question should be why is it still in a 33?

[Eug]

First question should be why is it still in a 33?

its not.

[D-limo]

its not.

It's not the first question? Or it's not in a 33?

[BADR33]

R.I.P.S in new zealand makes adaptors for rb26 throttle bodys to rb25 heads. if rb26 ones are hard to find use some 4age throttles. sure you will need 2 sets but they will still work but thats alot more custom parts though... they make small air filters to fit on ITBs

you would be lucky to find a direct fit kit as nobody really makes performance parts for NA skylines. i havnt even seen an after market intake pipe...

[Eug]

It's not the first question? Or it's not in a 33?

the later, its an R32 - the headlight and grill are a dead giveaway.

R.I.P.S in new zealand makes adaptors for rb26 throttle bodys to rb25 heads.

you would be lucky to find a direct fit kit as nobody really makes performance parts for NA skylines. i havnt even seen an after market intake pipe...

agree. worked NA skylines is hardly widespread in japan let alone anywhere else.

any idea on the cost of these adaptors Geoff? might be a cheap alternative to using an RB26 head.

[Simon-S14]

if you were going to do this you'd need to go all out.

forged high comp pistons, lighter rods, balanced bottom end with around 11.5:1 Comp ratio, some nice meaty cams, maybe 288's or something around that with a shortish duriation but high lift. basically want to make the bottom end hold together and swing to around 10,000 rpm.

defo use a plate and use the RB26 ITB's, make some nice and long intake trumpets, big air box feeding air direct to all of them.

and then put it in something light...

[funkymonkey]

I read in an option mag a guy used the throttles off an L28 kit and mated it up to some mikuni's. It'd be well cheaper in oz to use webers.

[D-limo]

the later, its an R32 - the headlight and grill are a dead giveaway.

my bad

[sil25]

those of you who frequent these formus will remember not to long ago i did a write up on my car well i've changed direction and kept it rb25 and gone hi compression.

looking at anywhere from 11.5:1 to 12:1. did alot of work to the head including lifting all the buckets getting all the valves reseated and 5 angel cut ( takes a long time is expensive but its the best!!) new valve springs and of course a port and polish. getting the intake polished and the manifold double split. getting the whole lot balenced before she goes back on to. slotted in new fuel rail to support 440 injectors. big cams, cam gears blah blah blah.

forgotten a few things im sure but you get the idea. After many weeks and many long hours i get her back this week and put it back on this weekend. so if anyone is after figures i'll have them next week after she goes to the tune shop.

as for ITB's i did alot of research on cost gains everything and they just not worth it. the gains you get can be gotten elsewhere for much cheaper and its nothing you can't tune around if you have a good computer and a tuner who knows what their doing. that being said the sound and look is unbeatable.

[Eug]

i demand a dyno printout!!

[andylaurel]

^^^ i had an AE86 for about 18 months...

the difference between single and multiple throttles is quite noticable.

[RB20DET_Silvia]

Do not use mini pod filters or socks to filter your throttles.....this completey wrecks the point of having a trumpet on there as it create far to much disturbance in the air flow as it try to pass over the trumpets completey wrecking there use.

There is a certin filter used by club cars and bikes which was invented in UK and are now made in Australia also. It other full filtering but with zero restiction.

When i had my hachi i spoke to a guy in UK who builds race engine which have quad throttle bodies and he has had gains of up to 30hp by just pulling off the sock filters and using these special made items along with a good setup.

I would make a base plate that sat on the lip that rolls back over the outside of the trumpet so it has more volume area to suck from and have one big single filter over the whole set of throttles making sure you give atleast 2cm of gap from filter to the ends of each trumpet. The filter is not like ur pod filter type it more like a long bubble looking filter thats made of 3 different filter materials.

If you need more info about these special filters that other full flow and zero restriction hit me PM and i can try to find his email address.

But when it comes to NA you want to try and get every extra HP you can and use your main source of air flow to its max potential.

- Luke

[funkymonkey]

^^^ i had an AE86 for about 18 months...

My condolences

[BADR33]

the later, its an R32 - the headlight and grill are a dead giveaway.

agree. worked NA skylines is hardly widespread in japan let alone anywhere else.

any idea on the cost of these adaptors Geoff? might be a cheap alternative to using an RB26 head.

um from memory it was about $500 witch to me seemed expencive.. but then it means it would fit well.

a super high powerd na car would be almost undrivable on the street i recken.

im aiming for about 150kw witch i have reciently found out is quite easily achievable with my rb30de.