Steve 90 Posted January 10, 2009 Share Posted January 10, 2009 Original plan was to stick with std Range rover manifolds and fab some front pipes that are well tucked away to go with the 4.2 RV8 that im fitting to my truck. All the aftermarket std front pipes are poor (and thats being kind to them, They really are terribly made) so thats out of the question. But, with an ever increasing "to do" list I need to start looking at some ways of lessening the work load or I'll never get to drive the thing. So what tube headers are available at reasonable cost and tuck away nicely between the chassis and auto box when fitted to a 90? Im sure I will have to make some adjustments to get them how I'd like but something somewhere near as a starting point would be great. Cheers. Steve. Quote Link to comment Share on other sites More sharing options...
landmannnn Posted January 10, 2009 Share Posted January 10, 2009 What are looking for, more power at the top end or mid range? By poor quality do you mean the welding or the gas flow characteristics. The oe manifolds aren't so bad if you have a pair already... Quote Link to comment Share on other sites More sharing options...
Steve 90 Posted January 10, 2009 Author Share Posted January 10, 2009 I have no problem with sticking with the std cast manifolds but the front pipe welding is poor and the bends and the "Y" branches are terribly made and very restrictive. Im not too bothered what the power gains are as long as they aren't power losses which is what I suspect you would get from the aftermarket front pipes. In an ideal world a gain in mid would be nice but if its all I can get at reasonable money I could live with a top end increase. Most important is that they fit between the chassis and dont hang below the bottoms of the rails. Preferably tucked up out of the way a good bit. Cheers. Steve. Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted January 10, 2009 Share Posted January 10, 2009 Steve, Most tubular headers are 4>1 This for you is as bad as it gets 4>1 means "Move power up the rpm range" IMHO you want twin cast manifolds a la 3.9s (also dumps the heat at 0 MPH and big RPMs better than steel tubular headers) and some decent twin downpipes to the Y piece not all of the exhausts are as bad as each other worth having a hunt about 4.6s have a horrible unit that cracks so forget them. Twin cast manifolds give 4>2>1 which is low and mid range Power which is what you DO wnat HTH Nige Quote Link to comment Share on other sites More sharing options...
Steve 90 Posted January 10, 2009 Author Share Posted January 10, 2009 Steve,Most tubular headers are 4>1 This for you is as bad as it gets 4>1 means "Move power up the rpm range" IMHO you want twin cast manifolds a la 3.9s (also dumps the heat at 0 MPH and big RPMs better than steel tubular headers) and some decent twin downpipes to the Y piece not all of the exhausts are as bad as each other worth having a hunt about 4.6s have a horrible unit that cracks so forget them. Twin cast manifolds give 4>2>1 which is low and mid range Power which is what you DO wnat HTH Nige Yep, I totally agree Nige. Trouble is, after a lot of time searching and ordering and sending back numerous sets, I really have failed to find a decent set of twin front pipes. Which is why I decided to make my own. But no, is times against me, again! Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted January 10, 2009 Share Posted January 10, 2009 Yep, I totally agree Nige. Trouble is, after a lot of time searching and ordering and sending back numerous sets, I really have failed to find a decent set of twin front pipes. Which is why I decided to make my own. But no, is times against me, again! The real issue is the 2>1 normally - they "Crush" them into 1 which is a real bodge, on my old racer I bought a std twin downpipe(s) then cut off the crushed mess and added a Jetex 2>1 properly formed unit and welded them on in exactly the same exit point made a huge difference and was quick to boot ??? Nige Quote Link to comment Share on other sites More sharing options...
landmannnn Posted January 10, 2009 Share Posted January 10, 2009 On a racer you need gas flow unrestricted so crimping pipes at the junction is a bad move. I had a beautifully made 4 to 1 (matching cam etc) which made a huge difference at the top end, the bottom end was not great. For mid range 4-2-1 as Nige says is the ideal, surely crimped pipes are not a major problem, at the very worst they will strangle the top end, at the best they will increase back pressure which is what you need mid range. If time is tight you could do a lot worse than efi cast manifolds. Quote Link to comment Share on other sites More sharing options...
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