Extrude Honed Stock Rb25 Manifold Results

[SLY33]

I couldnt find the thread in which i posted the extrude honed manifold flow results(??), if anyone can find it please link.

I found another thread and will follow on from this..

"There is one bloke. I forget his alias. Orange R33 in his Sig.

I believe he had UAS power port/extrude hone his std exh. manifold but he is/was oversea's so he was unable to test.

He's running a gt2835 and currently making up around 280rwkw.

I'm very keen on seeing his results. Maybe UAS could shed some light on if the extrude honed std exh. manifold allows it to push considerably more than the 300rwkw brick wall the std exh. manifold usually see's."

Well the car has just been dynoed, and.....

no power increase at all. I havent seen the dyno sheet as im still overseas, but from what i heard from my brother was that they played around with it for ages in search of more, but came up with nothing. If anything it made the same power at slightly less boost im told.

It is certain that the extrude honed manifold flows more, and i think the lack of results is most likely due to the turbo itself, maybe even the wastegate issue that many people mention (but personally i just think its out of puff). Seeing that the 2835 is not commonly known to push up and past 300rwkw, id really need to put a 3037 on there to see if the stock manifolds brick wall can be pushed.

I know many were eagerly awaiting these results, its a shame theres nothing exciting to share,

cheers

[PM-R33]

Dam that sux I would have thought it would make a bit more power for sure, guess not.

[Dale FZ1]

Could you have a graph overlay posted up showing before/after comparison?

Shame that there was no quantifiable improvement, but it'd be interesting to hear if there was any different on-road feel to how it drives. I tend to agree that ~280rwkW should be pushing the max flow capabilities of the 2835.

What sort of price range to have the extrude hone done?

[SLY33]

it may be some time until i get the graph but will see what i can do.

Spoke to my engine builder today and he thinks the same, that with a bigger turbo you would most likely see differences compared to the stock mani.

dont quote me as im not sure (was a long time ago) from memory just over $400? And was done buy a place in melbourne i think, if anyone can dig up the original thread there should be the details... ill have another look.

[The Mafia]

what size is the rear housing on the 2835? I'd say that is the problem if its only a 0.63.

Then again, the compressor technically shouldn't go any higher than 280rwkw as it just isn't designed to.

Shame the turbo isn't a GT3037.

[juggernaut1]

I've had an SR20 6boost manifold done by Andrew Sanders at Specialised Power Porting who is based out of Mt Helen (near Ballarat I believe - not sure because I'm in Perth). From memory cost was around $550.

[noone]

Was under the impression UAS could no longer supply these??

[wolverine]

the guy in sydney is a little hard to find but i understand he is still doing them. the rumour is that he is busy doing other types of work and is fitting in the extrude honing around that at the moment.

[paulr33]

i do not see how it will add power

i can see how it would increase car response ramping on boost but not power increase

its likely youll gain some more torque / power earlier but overall peak should be the same

if you did the same to the turbine housing then i would say peak power could increase

[Dale FZ1]

In much the same way as increasing A/R size of the turbine housing, extrude honing should allow the manifold to increase its mass-flow capacity. ie. it can just put more exhaust flow through more efficiently. You have to look at it from the perspective of pressure gradient across the engine, not just inlet boost pressure. That the car did not make any higher peak power supports the general observation that the stock manifold is good for ~ 300rwkW of flow, and a 2835 with 0.68 A/R turbine is a touch short.

Waiting for comments from those who have exceeded 300kW with those components, but also want to know how comfortably and reliably it was done...

[wolverine]

sly33 do you have the before and after flowbench results at hand.

[PSI Parts]

I'm curious to see how many people are running more than 300rwkw through the standard exhaust manifold, regardless of turbo.

[WARLORD]

I'm curious to see how many people are running more than 300rwkw through the standard exhaust manifold, regardless of turbo.

i am 304kw atw

[wolverine]

i am 304kw atw

extrude hone time!

then post the results for us.....

Edited August 25, 2008 by wolverine

[PSI Parts]

i am 304kw atw

What turbo and boost setting?

[BHDave]

I'm glad you shared the results.

For better or worse it adds to the knowledge base and takes it a step beyond the "i reckon based on numbers" type thinking that a lot of us end up having to do based on lack of actual results.

Simple answer, $400 can be better spent elsewhere if chasing sub 300rwkw, much like .63 IW 3071 doesn't work

[WARLORD]

What turbo and boost setting?

3037 pro s 17.5 psi tuned by crd

Edited August 25, 2008 by WARLORD

[The Mafia]

314rwkw at 18psi here. GT3037 (The big one) with a 0.63 rear.

Can't go anymore, too much back pressure. I'm pretty sure thats the Exhaust housings fault though.

[PSI Parts]

Another interesting test would be to swap for an aftermarket low mount manifold made from stainless or similar. As there seem to be a whole bunch of sceptics about what performance gains a Jap brand exhaust manifold actually produces. Although not sure there are too many RB25 low mount off-the-shelf manifolds kicking around. Throw in tuned length and there are so many combinations that I would like to test haha

[SLY33]

to clarify, this was not done or obtained through UAS.

fairly sure mines the little 0.63, hence the 280rwkw wall.

i finally found the flow results. did someone say Andrew Sanders?!

Edited August 25, 2008 by SLY33