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Most Power Thru A Std Rb25 Intake Pipe

Harey

By Harey,
in Engines & Forced Induction

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Harey Veteran

Harey

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Hi All,

I am wondering what is the most power someone has made through a standard RB25 intake pipe? (it can be sleeved with pipe)

Mine is currently making 279rwkw and i am wondering if it has much left in it. I am running an apexi pod filter, it can be either airbox or pod as long as its running through the standard intake pipe.

Any help much appreciated.

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paulr33
paulr33

when you change to 3" intake do you also upgrade 3" intercooler pipework? i cant see the sense in it, if you don't do both

Harey Veteran

Harey

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Thanks guys, i am running a hiflow with the standard comp cover so standard 2.5" intake, so I cant see the value in anything bigger than the factory intake pipe. Tao from Hypergear made 302rwkw using the same turbo but with a 3" metal intake pipe so I am just curious to hear some other real world results. I am hoping for 290rwkw.

hypergear Grand Master

hypergear

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Run 3inch intake pipe. Will make better power, response, and keep the turbo cooler. You will find metal sleeve does all sort of strange things. 60rwkws difference on mine, It did not work for me.

Harey Veteran

Harey

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Run 3inch intake pipe. Will make better power, response, and keep the turbo cooler. You will find metal sleeve does all sort of strange things. 60rwkws difference on mine, I did not work for me.

Thanks Tao, I know your advice and I do value it.

I dont see the difference between:

pod > 3" afm > 3" pipe to 2.5" turbo inlet

pod > 3" afm > 3" pipe to 2.5" pipe to 2.5" turbo inlet

The only difference is that the standard pipe reduces to 2.5" (same size as turbo inlet) 8 cm earlier.

I understand completely if the turbo inlet is bigger than 2.5" but I just cant see the logic yet. If I lost less than 10rwkw I would accept that as my engine bay looks completely factory with a pod (my intercooler is also very hard to spot).

Oh well we will find out next thursday if it will max out.

Harey Veteran

Harey

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I was recommended by unigroup to upgrade the intake...

i did make good power so i suppose it must have helped.

Thanks for your experience, only difference is you are running a turbo with a 3" inlet so using the standard intake would be an obvious reduction in diameter (2.5"). Also it just wouldnt fit.

scotty nm35 Grand Master

scotty nm35

Posted
Posted

I just made an 80mm alloy intake for GTR 26 on his 34gtt, it will be interesting to see the gains on his 3076 once Trent tunes it, I think the stock rubber intake maxed around the 270 mark.

Bigger is better for the suction pipe, and a good bell mouth into the turbo helps.

Touge Kyousou Experienced

Touge Kyousou

Posted
Posted

Interested in this myself.

I'm currently running 250rwkw on the standard pipe and have always wondered if it's upto the job. It's been reinforced with some pvc piping but there's a pretty nasty bend in it and the bend isn't reinforced.

Having less length of the 2.5" piping will increase flow and i'm sure the aftermarket piping will have a smoother internal make up and most important a smooth bend whilst not collapsing at all under vacuum.

I wonder if changing the pipe will bring enough difference to require a retune as that's whats holding me back from changing the pipe (and a couple other higher priority items i want to replace).

scotty nm35 Grand Master

scotty nm35

Posted
Posted
Interested in this myself.

I'm currently running 250rwkw on the standard pipe and have always wondered if it's upto the job. It's been reinforced with some pvc piping but there's a pretty nasty bend in it and the bend isn't reinforced.

Having less length of the 2.5" piping will increase flow and i'm sure the aftermarket piping will have a smoother internal make up and most important a smooth bend whilst not collapsing at all under vacuum.

I wonder if changing the pipe will bring enough difference to require a retune as that's whats holding me back from changing the pipe (and a couple other higher priority items i want to replace).

I made about 30 kw more with mine so yes, you should definitely get on the dyno at least to check afr's top end.

Touge Kyousou Experienced

Touge Kyousou

Posted
Posted (edited)

Cheers mate - What engine/setup was that on i.e. Your vq or on an rb motor?

Yeah thought the tune would need to be tweaked... i might leave it then as i'm pretty happy with the power anyways. When i do change it eventually i'll do it at the same time with a forward facing plenum and a retune to suit.

WOMG DOSE!

Edited by Touge Kyousou
scotty nm35 Grand Master

scotty nm35

Posted
Posted
Cheers mate - What engine/setup was that on i.e. Your vq or on an rb motor?

Yeah thought the tune would need to be tweaked... i might leave it then as i'm pretty happy with the power anyways. When i do change it eventually i'll do it at the same time with a forward facing plenum and a retune to suit.

WOMG DOSE!

Mine is VQ25det, but flow into a turbo doesnt change with engine type. Suction pipe size is important as the air isnt compressed like Stao mentioned, its at less than atmospheric pressure so less air travels down a 3 inch intake pipe than the turbo can blow down a 2 inch, good power gains to be made there.

XRATED Veteran

XRATED

Posted
Posted (edited)

3" alloy hard pipe, split the stock rubber intake down the middle, then wrap it over the alloy pipe. As long as you cut it correctly and use an extra hose clamp it will look factory.

I'd also run a stock air box with some 'slight' modifications to cut down on the fuuuully sizacccc 'dose' sound.

J.

Edited by XRATED
Touge Kyousou Experienced

Touge Kyousou

Posted
Posted

Cheers for the info. Good idea on wrapping the factory pipe over an alloy one too, hrmm!

I was looking at getting a silicone intake pipe in black though so should still look fairly harmless, and being silicone shouldn't make noises anymore hektik..

Ahh on a vq. I agree on no difference with air going down the turbo however the factory design of the intake pipe between an br25 and a vq25 would be vastly different i'd daresay e.g. one is happy to flow decent whereas the other may not. E.g. on my v35, that intake pipe had a large and a smallish resonator tee'd off for NVH whereas a skyline from the 90's probably wasn't as focused on NVH. Damnit, now i'm looking at intake pipe, plenum, and retune blargh! (i'll do it later)

Harey Veteran

Harey

Posted
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I just made an 80mm alloy intake for GTR 26 on his 34gtt, it will be interesting to see the gains on his 3076 once Trent tunes it, I think the stock rubber intake maxed around the 270 mark.

Bigger is better for the suction pipe, and a good bell mouth into the turbo helps.

That will be very interesting, if you could update this thread with the results that would be great! :(

Yeah if those bellmouth things make more hp I can see the benefit of having a larger intake pipe immediately from the turbo.

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