RB25DET Head porting info

[mambastu]

Hi all,

I've just stripped my RB25 and will be porting the head on it tomorrow. After a quick look at the ports I've noticed there are large 'bumps' just inside the exhaust port, next to the manifold flange. It looks like they are there to add strength to the manifold stud area but they're pretty intrusive.

Does anyone know if they can be removed safely ?

[BOOSTD]

I ported that exact bit in the chase for improved flow. I removed 2mm without any trouble.

[dabigbolf]

i take it you did other mods at the same time, thus not knowing the improvement.....

[BOOSTD]

ported the exhaust mainifold and installed the VG30 hybrid which "was" making 15psi by 2600rpm.

[dabigbolf]

and now your making 245 rwkw on just .9 bar.... with that same turbo.....

i am going off your avatar....

[Steve]

BOOSTD, want a customer?

[benm]

for a dummy what does "porting the manifold' do/cost/etc ?

[EnricoPalazzo]

increases flow in the head basically = more power...

[hungry6]

on my last motor i rounded oval the port area mention, but more was to be had by doing it around the valve stem area.

[T0nyGTSt]

Basically you get a dremel tool, round out all the corners, grind the dags, makes the gas flow fast and smooth.

I'm doing it to my head. You should too.

T.

[benm]

Can it be done at any time or should it be done after certain mods or ?

When you say increases flow therefore power what sorta power increase can be expected ?

[BOOSTD]

dabigbolf: The turbo is different, I went to a highflow VG30. It spooled up alot quicker than it should have tho.......

Steve: I have access to a die grinder and bits, however in hind sight I was lucky to not put a hole in the manifold.. I took a hell of alot of metal out. I would definately invest in a pair of pinchers to keep an eye on wall thickness.

[Steve]

BOOSTD, just looking at getting the head tidied up and maybe matchporting intake runners. I dont have all the tools necessary to get the head off though:( Its just sort of seems a shame as I gotta get the head removed, but to go the next step of complete disasemble and mild port is going to double the cost - have to stay on the wagon a bit longer:)

[Guest INASNT]

I know a place in mel that will do a mild street port for around $450. That will be happening to mine if the engine starts to feel or sound a bit used.

[Bl4cK32]

What do you mean by "mild street port"?

[Guest INASNT]

not 100% sure but prob cc chambers and just a bit of basic head work. They dont take 2 much metal out so u wont be blowing head gaskets

[Bl4cK32]

Well here in Adel. I'm getting a total recon(new stem seals, re-shim valves etc.), then for an extra 300 they're doing some mild porting, (cleanup of valve openings etc.), like u said.

[Guest INASNT]

whats your costing u?? around $1200?

[Bl4cK32]

no way man. Its ~400 for the Full recon then ~300 for the mild port job.

edit/ i bought the vrs kit for the head as well which cost ~260, so I supplied valve stem seals to head place

[Steve]

Are these the guys on main north road? cant remember their name/address now:(