I have heard of people fitting exhaust headers or extractors to their RB25DE powered Skylines.
I have an RB30DE engine which I am building with an RB25 cylinder head and I was going to use the RB25DE exhaust manifold at the time as today was the projected date I was going to fit the engine but due to lack of funds and the ever so slow flow of parts coming in (still waiting for the airflow meter and injector wiring loom after 6 weeks of buying the RB25 package) I am going to fit it later and was thinking I may as well fit some aftermarker headers.
Apparently the aftermarket manufacturers here do not make a header for that engine,but I was told the import wreckers sell them,but my local importer doesn't know anything about them,does anyone know an importer who sells them?
You could always just buy an RB30 header or extractor. All you would have to do is just cut the piping of brace were it bolts to the block and turn it upside down, because the holes run the oppisite way on the block. Then you just weld them back on and away you go.
Some original photos have not been recovered yet.
just get rb30 extractors, and an RB25 head flange, most exhaust places should be able to get one for you, and get them to cut the RB30 flange off and weld the rb25 flange on. pipe spacings are the same. The flange design isnt just upside down it is a different layout. the RB30 is / / / / / \ and the RB25 is / / / \ \ \ from memory.
I have been thinking about this today as I remembered the RB30 block was 40 mm taller than the RB25 block meaning the RB25 headers cannot be used.
I am going to get some headers and have the flange cut off and a new one welded on,the only gripe I have about that is the cost of a decent set of headers as the Pacemaker set in my brothers VN which work well I might add,cost $500,might be cheaper for an RB30 though,it's not so much the cost of the headers,it is the added cost of modifying them.
The stud pattern appears to be upside down to the RB30 pattern but I also think there is more to it than that.
the stud pattern is a totally different layout than the RB30. You will need an RB25 flange - these go for about $40 and it shouldnt cost too much to get someone to cut the old one off and weld the new one on. If you can use oxy/acetylene and a welder you could do it yourself. I am in the same boat as i had a custom exhaust manifold made up for my VLT when i was using the single cam head but i need to modify it now to suit the RB26 head. Genie exhausts were going to send a flange to my doorstep for about $40.
So Genie actually make a flange plate to fit an RB25 head?
I was thinking about buying a piece of 10mm thick plate and marking out my own plate,perhaps using a second hand set of headers.
the RB30 pattern went like this when I checked:-
///// \
THe RB25 pattern is more like this :-
\\\\ //
.
if you want to get one made the easiest way is to get an exhaust gasket and take it to a metal fabrication place and get them to cut you one on a profile cutter, this machine actually traces the gasket and cuts an identical shape out of the plate. Dont know how much they would charge for this.
Wish they were that cheap,mine is damaged and they cost $102 from Nissan,I am tracing the pattern from what is left of the gasket and cutting my own out.
As for the manifold orientation the last 2 cylinders face opposite to the first 4 cylinders, whereas the RB30 it is only number 6 which faces opposite to the first 5 cylinders.
