Following the success of the tailshaft thread I've decided to ask you guys to help me out in my injector hunt. Sure I've searched but as I've said before, it's like a chinese takeaway. On top on that I get confused real easy. This lot has me interested.Suggestions welcome. Keep in mind I'm chasing about 650rwhp. These are 850cc and are about a grand, big enough? By gargoyle123 at 2011-07-29 By gargoyle123 at 2011-07-29 By gargoyle123 at 2011-07-29 By gargoyle123 at 2011-07-29
Nismo 740s in 300 degrees rail. Better injector and better spray pattern, injector will sit in the port better... Easier to tune and better low load driveability... Those ams rails look to be knockoffs of the border fuel rails which are poorly designed.
My personal opinion, (and if they were available when I did my fuel system I would have gone down this path), if you going to be dropping a gorilla on a new rail and new injectors, I'd go for the top feed rails at z1 at the moment. Much better choice of injectors and usually cheaper as well (supply and demand), also they are easier to access in the future should you need to change them. And 2 last points that may or may not be of concern to you...very few people here run top feeds, and only with top feeds will you ever run methanol. Both these things will make you very cool. :rofl:
Thick billet rails don't really work with that style of injector. The spray pattern is wider than OEM, and the nozzles don't penetrate very far into the ports, so fuel tends to spray against the edge of the port rather than through like they do with the factory setup. Couple of clips of bench testing that UAS did when I was choosing an injector setup OEM [yt]8kQ1DM-aC8E[/yt] The second vid is some SARD type pintless 850cc injectors in a rail that UAS were trialling. Very similar design to Border.. we ended up sending it back. [yt]UUEpYhrxxI6WM[/yt] Now some (including Tektrader whose opinion I hold in high esteem) have suggested that these tests werern't entirely accurate as the manifolds weren't under vaccum. I took my chances and went with my engine builders advice and went to Nismo. Unfortunately I don't have any vids of the Nismo injectors. FYI Mike Smith (of the manifolds fame) published some pics a little while back of injectors firing into a cup and reached the same conclusion http://twinturbo.net/net/viewmsg.aspx?forum=general&msg_id=1667783 I believe the "problem" is not as bad when fitting SARD/Power Enterprises/Denso/etc style injectors to the factory rail as they protrude further into the port compared to aftermarket rails. So yeah back to Border style rails, I suppose to say they are designed "poorly" is a little unfair. Better to say therer have been improvements made since then! The 300 degress rails flow plenty, are thermally insulated (which Border are not), and with the Nismo 740 option will I think be a better choice. You probably wouldn't notice the difference at WOT but I am convinced that the Nismos will give better atomisation and better low speed/low load tuning.
From what I'm hearing 740cc Nismo's and a 300 degree fuel rail is the go. I'll put them on my shopping list if nobody has any objections. Thanks for the detailed info Rob.
If going top feed BDE is the way to go, I think some guys on Twinturbo.net have had problems with the fittings on those winfactory rails.
Yeah Brett's stuff is really nice and will give you a shitload of fuel. You don't need to go that large though, the 740s will supply plenty of fuel. The advantage with the top feed kit would really be if you wanted to run high alcohol content fuels in which case you will need to extra cc's
