Gains From Aftermarket Manifold

[sweefu]

G'day all,

I am just finding my way through a turbo setup for the first time, coming from only n/a performance before this. The setup is on my RB30E in my R31 skyline, I realise this isn't the R31 club but my question relates to turbo motors in general. What sort of gain might I see, from using a stock cast iron log style manifold, to a mild steel steampipe style manifold? The price difference is maybe $150 - $200 for stock manifold and $330 for the steampipe style manifold, which is a highmount also, if that makes a difference.

Here is a picture of each so it is clear which manifolds I mean:

http://img690.imageshack.us/img690/1058/rb301.jpg

http://img153.imageshack.us/img153/7128/rb303.jpg

Stock manifold

http://img.photobucket.com/albums/v211/das_moogan/VL%20Turbo%20conversion%20smaller%20pics/VLTurboTopView.jpg

My setup isn't going to be huge, just an rb25 turbo for the moment, Bosch 271cc injectors, 2.5" exhaust with high flow cat, cold air intake, 10mm leads, front mount intercooler and 2" piping. I am hoping for a responsive setup, with at least 160rwkw through my 28spline minispool diff.

Would I see any advantage with the better manifold? Or is it a substantially better base if I ever do go chasing more power?

Thanks for your help / input.

[zebra]

With a standard RB25 turbo it will make ZERO difference, and is setup for an externa l gate.

However as you say, if you want to go bigger than you already have it ready to go

[sweefu]

With a standard RB25 turbo it will make ZERO difference, and is setup for an externa l gate.

However as you say, if you want to go bigger than you already have it ready to go

Thanks for the quick reply mate.

I would have the external gate welded shut while using the RB25 turbo.

If I would see no difference between manifolds when using the RB25 turbo, when do you think I would see a difference?

With an RB30 turbo? Or would it have to be substantially larger to make any difference?

[zebra]

yeah lots larger!

Think GT30 and up

Also

can I ask where you get a steam pipe manifold for $330 bucks!!@!::?? IS it new.

Even with mates rates I cant get one for under 500

[sweefu]

Ah Okay, thanks very much for clearing that up mate. I don't imagine I will go that large, because that would mean changing my fuel pump and injectors for larger items.

Perhaps steampipe is the wrong word? I think that's what they are, as the pictures indicate. I will send you a PM with where to get them mate. The welds can be poor sometimes, but they are easily fixed up if you are handy; I get my friend who is a boilermaker to do it for me.

[r33_racer]

Steam pipe is close enough, the actual bits used are called buttweld fittings.

[Bsa]

In used a 25 turbo on both stock and stainless highmount manifolds and I found the stainless highmount to spool the turbo faster not by much but enough to notice had no power difference though.

[sweefu]

In used a 25 turbo on both stock and stainless highmount manifolds and I found the stainless highmount to spool the turbo faster not by much but enough to notice had no power difference though.

Thanks for the reply mate .. Didn't happen to have a dyno before and after did you? Haha

[dori34]

those are the manifolds on ebay yeah?

read the feedback reviews, some ppl say the quality and weld jobs are shocking! i was looking at them as well and the priced looked good.

[sweefu]

Yep those are the ones mate. I agree, even from some of the pictures you can see there must be pinholes / very thin welds in some places. Not a huge issue for me considering the price ($330 landed) my friend is a boilermaker, so if I do buy one I'll give it to him to look over, he will fix up any welds for a 6 pack, then I can repaint and have myself a fairly cheap manifold. Likewise, the quality of the flange is not great, there is not a proper merge pipe. Again, I feel the price reflects this.

[Bsa]

I'm a boily to so I got one actually was is in great condition all I did was crack test it before all came back good they are decent quality for cheap. Na didn't dyno it popped the turbo before I could. They are a bitch to highmount to be honest and kind look sill I'll post a pick so you can decide for yourself. Look so small

[sweefu]

Sweet mate, did much need fixing with the manifold? Pictures would be awesome.

[R31Nismoid]

Problem is it's not just the quality of the welds, it's the actual metal it's made out of.

Cheap grade will run the risk of cracking, bending and so on.

Thats why the ebay stainles ones for the majority tend to crack/fail as their walls are thin - it's not just a welding issue.

Under 300rwkw - stick to the stock manifold as plenty use it without a problem.

Better to go with tried and proven rather than taking a gamble and then it failing.

[Bsa]

thats on a rb20 wall thickness on the pipe was 2.5 mm that is more then thick enough the problem with stainless is it expands and shinks a fair bit so on the out side of the weld is the most brittle but if you get 2 years out of a 250 dollar manifold money well spent. i wouldnt high mount a nissan turbo again unless high flowed so much stuffing around for min gain. only reason i did it was beacause i was setting up for a bigger turbo but i poped it so plans sped up. i agree with R31Nismoid just use the log style unless you put a decent turbo on

[r33_racer]

If they used a better grade of stainless it would be alright. But they probably use something like 304s.s which wouldnt be the best choice. If they used stainless buttweld fittings it would work great. Have the benefit of heat retention in the runner and no rusting or need for painting/coating and if you wanted it could be polished to look pretty.

[gotRICE?]

Will 270cc injectors even be big enough for a stock turbo application? Mine maxxed out very quickly with the stock RB25 turbo. 100cc more obviously.

[Moodles2]

General rule of thumb is for each 1cc supports 1hp, so 270cc being a theoretical max of 270hp.. in the real world it will be more likely 240-250hp

[sweefu]

Will 270cc injectors even be big enough for a stock turbo application? Mine maxxed out very quickly with the stock RB25 turbo. 100cc more obviously.

271cc are the stock Bosch 'Brown Top' injectors which come in a VL Turbo, many people make 150 - 160kw (200 - 220hp) with these injectors. In an R31 setup, the fuel pump (Bosch 070?) runs out before the injectors, somewhere near 170kw usually.

[DVS JEZ]

Price it all up including fuel pump and injectors etc.

Then price up an rb20 or 25 conversion.

Have a think ahead about what ur plans are including power goals etc.

[sweefu]

All up the conversion to RB30et will cost me about:

Intercooler $35

Piping $50

Silicone joiners $free

Turbo $50

Manifold $150 - $300 (depending on which I get)

ECU $90 - $200 (depending if I get VLT or get a retune)

Injectors $35

Dump / front pipe $50

Oil line $70

Misc $50

So all up $580 - $840 depending on a few things. I think this would make good responsive power, the end figure I'm not very fussed about, just after a responsive setup, with more power than I have N/A, which is a given. An engine conversion would be a heap more work, and would cost more than the VLT setup.

Edited October 20, 2011 by sweefu