Cheap Aftermarket Exhaust Manifolds Vs Stock

[Vanilla_Rice]

If this has already been discussed can someone please point me to it as I cant find any info..

Im about to revert back to a t3 flange turbo from going down the td05 path and need to eigther buy a stock unmodifed manifold for my rb20 or get one of these cheap $350NZD ones (not spending thousands on a flash one) to accomodate for it..

looking for around 250kw+ atw with the new turbo just need some helpful advice on weather id see any gains with manifolds like these or just go for stock again:

http://www.trademe.co.nz/Trade-Me-Motors/C...n-203672556.htm

Dont care about the cosmetic appeal, turbo will most likely be gt3040 so opinions on top vs side mount am keen to hear any clearance issues etc..

thanks in advance.

[daxter]

Thing with those cheap manifolds is some work and some don't, some of them can make the turbo hit the bonnet or make the turbo push up against the rocker cover stopping it from fitting properly.

However friend has one on his RB20DET and it works fine, so just luck of the draw really.

Also, stay away from these manifolds -

They give no performance gains and without extra reinforcing they crack very easy.

[The Dan]

Use the stock manifold. 250rwkw is nothing to ask from one of those. In fact they are better than aftermarket options in many ways.

I'm not going to get into a debate with other people on here about the pros and cons of cast vs steam pipe or stainless and short runner vs tuned length but I can tell you the stock manifold will have no flow restriction at those power levels and you will not notice any real improvement from merge collector designs on smaller power outputs.

[Vanilla_Rice]

Use the stock manifold. 250rwkw is nothing to ask from one of those. In fact they are better than aftermarket options in many ways.

I'm not going to get into a debate with other people on here about the pros and cons of cast vs steam pipe or stainless and short runner vs tuned length but I can tell you the stock manifold will have no flow restriction at those power levels and you will not notice any real improvement from merge collector designs on smaller power outputs.

yeah I have heard good things about the stock manifolds.. but what about the clearance mounting a gt3040 onto it? I shouldnt run into any issues should I?

[The Dan]

Yes you will. You will need a spacer of around 10-15mm and slightly longer studs to hold it together.

[TiTAN]

but why do you want to use a GT3040 to get 250kw? a GT3071 or GT3076 is much better suited to the application and doesn't have the extra lag.

[Vanilla_Rice]

but why do you want to use a GT3040 to get 250kw? a GT3071 or GT3076 is much better suited to the application and doesn't have the extra lag.

yeah true TiTAN, 250kw was basically the figure I wanted to get to but ill take anything over that 260, 270 who knows.. After going over the dyno results page it appears every gt3040 has easily over 250kw .. but having said that, most if not all of them have had bottom end work done, I on the other hand have not.. Id like to see more dyno printouts with the 3076 on an rb20 but have only seen one result at present, making 227kw if i recall but no printout.. I almost made that with the TD05, just dont want to run the risk of spending heaps on a new flash turbo if it isnt going to give me the peak output power im after. How much more lag are we talking about after all? I really have no idea how much sooner the 3076 will come on boost or weather I can gauruntee itll put me in the 250+ area

[TiTAN]

The 3076 is capable of 300kw it will do the 250 you are after, the 3071 is being pushed to get much over 250kw.

[R31Nismoid]

GT3040 or whatever is 600hp worth of turbo in its biggest form.

Thats over 300rwkw.

If you do not want that, and only want 260rwkw, get a 450-500hp item thats better suited to the job

[Lithium]

I had a DSR one on my Skyline when I went GT30R and it ended up cracking - I got rid of the DSR manifold and have put a stock one back on and can't say I have noticed any difference though will have to hit the dyno at some point to confirm. I obviously prefer the stock manifold given it doesn't fall apart haha

[Vanilla_Rice]

sounds like ill be sticking with the stock option for now ... i find it crazy that these aftermarket ones can crack, I suppose its to do with them expanding and contracting all the time.. found another stock manifold for $75NZD hell of a lot cheaper than a dud aftermarket one..

[gotRICE?]

Thing with those cheap manifolds is some work and some don't, some of them can make the turbo hit the bonnet or make the turbo push up against the rocker cover stopping it from fitting properly.

However friend has one on his RB20DET and it works fine, so just luck of the draw really.

Also, stay away from these manifolds -

They give no performance gains and without extra reinforcing they crack very easy.

Yeah these really do not like the heat cycling on a street car. If it was proper grade stainless it might work fine. And the weld at the collector seems to let go and burn the bonnet

[Lithium]

Yeah these really do not like the heat cycling on a street car. If it was proper grade stainless it might work fine. And the weld at the collector seems to let go and burn the bonnet

Haha yeah I wonder where you've seen that

Redline performance sell a pretty cheap low mount manifold, one of which a guy I know of has used on his RB20DET powered S13 that goes VERY well (its running an EVO TD05 - its the same running gear from ADIDAN's R32 GTSt which was later crashed, Vanilla Rice) and that seems to work quite well, again unfortunately no dyno results yet but one thing I like about it is it happens to resemble little sketches I had been drawing and sending to people who can fabricate (alas I lack such skills) asking if it were feasable to make up, and if it would work.

Its essentially has two 3>1 headers and then 2>1 at the flange allowing something resembling proper collectors to be made up unlike most cheap low mount manifolds. It has the "tubular exhaust manifold" sound and feel to it and certainly hasn't lost anything over the stock manifold and most importantly hasn't cracked yet despite being street driven and run at 20psi so it could be promising. I have been watching with interest for a while.