V8Pete Posted July 5, 2007 Share Posted July 5, 2007 I want to meke me a custom inlet manifold at some point probably with thin-wall mild steel runners because of the weird shapes and angles it'll need to fit. With this setup, I'm unlikely to have sturdy fuel rail mounts, and I probably won't be able to get them in the right place anyway with my vice grips, MIG welder, and general incompetence. I found I can get adaptors to run hoses off the end of the injectors instead of (presumably) having them inserted in a fuel rail. I've also found when I've pulled injectors out in the past that you need to pull bloody hard. Does this mean the friction fit of the injector o-rings in the inlet manifold and stiffness of hoses is enough to hold them in, or would I be running the risk of an injector popping out and spraying petrol all over the engine bay? I was dreaming up a little hook latch thing that could loop over the bit of hose at right angles to the injector for peace of mind. Then I found these things which look bloody rugged, and I assume I'd just need to weld a huge nut on to the runner. They're massive and ugly though. Whaddayareckon? Quote Link to comment Share on other sites More sharing options...
Burntrubber Posted July 5, 2007 Share Posted July 5, 2007 A lot of 80's injected cars ran hose tail injectors. They bolt to the manifold with a number of different design brackets. I have an injected Piazza engine they use hose tail injectors. The shape of the injectors is the same as many o-ring injectors I modded some falcon ones to fit but they were high impedance the ecu wouldn't have liked that. You will need to find a way of mounting them solid otherwise you'll probably get vacuum leaks or they'll pop out if its boosted. Those mount things look sweet dunno bout welding a nut on if you did you wana make it so the injector points into the port not at 90' to the runner. Quote Link to comment Share on other sites More sharing options...
zep Posted July 5, 2007 Share Posted July 5, 2007 If those little mount things have the injector sitting in them so that they squirt out the bottom (through where the thread is), could you not just tap into your manifold where your injector usually sits and screw them in? Use some lock-toite and that should keep them pretty secure. I would imagine that if you are building your own system, you'll want to steer clear of hose-tail injection. Good if you're trying to keep things cheap and easy, but I haven't heard anyone proclaiming godly status toward them. Is your application boosted? Quote Link to comment Share on other sites More sharing options...
V8Pete Posted July 5, 2007 Author Share Posted July 5, 2007 A lot of 80's injected cars ran hose tail injectors. They bolt to the manifold with a number of different design brackets. I have an injected Piazza engine they use hose tail injectors. The shape of the injectors is the same as many o-ring injectors I modded some falcon ones to fit but they were high impedance the ecu wouldn't have liked that. You will need to find a way of mounting them solid otherwise you'll probably get vacuum leaks or they'll pop out if its boosted.Those mount things look sweet dunno bout welding a nut on if you did you wana make it so the injector points into the port not at 90' to the runner. Any chance of a pic? Quote Link to comment Share on other sites More sharing options...
mikuni Posted July 5, 2007 Share Posted July 5, 2007 We just did this on my car. Because it was too much of a prick to put the injectors on the top, due to throttle linkages etc they went on the bottom. Looks cool, but its not ideal. The injectors are supposed to point straight down the valve but in some cases this just isn't possible. How much it affects the performance I'm unsure of. To hold the injectors in there is just small sections of pipe, the same size as the injector O-ring and then the fuel rail bolts in over the top. As these were welded in the shrunk and distorted slightly, so I wasn't expecting a good seal but it seems to have worked fine. We just used the standard fuel rail cut down slightly and with the fuel intake and outlet modified. The standard fuel pressure reg was also cut off to allow a little more space and an external one was used. I don't think you'd want to go away from using a fuel rail because thats the only system I've seen used. The injectors all need to sit with a constant flow of fuel running past them and at an egual pressure. Quote Link to comment Share on other sites More sharing options...
V8Pete Posted July 5, 2007 Author Share Posted July 5, 2007 If those little mount things have the injector sitting in them so that they squirt out the bottom (through where the thread is), could you not just tap into your manifold where your injector usually sits and screw them in? Use some lock-toite and that should keep them pretty secure.I would imagine that if you are building your own system, you'll want to steer clear of hose-tail injection. Good if you're trying to keep things cheap and easy, but I haven't heard anyone proclaiming godly status toward them. Is your application boosted? Not boosted. Was thinking of drilling and tapping, but I expect the area where I want it to be where the thin-wall stuff and end plates join so might be hard to get right. What's wrong with hose-tail injection? Leaks? There are also ones with threaded ends available, but I could only find BSP ones for the injectors, and Earl's stuff's all NPT Any thoughts on that? Might end up with adaptors and shit longer than the injectors Chur Quote Link to comment Share on other sites More sharing options...
V8Pete Posted July 5, 2007 Author Share Posted July 5, 2007 I don't think you'd want to go away from using a fuel rail because thats the only system I've seen used. The injectors all need to sit with a constant flow of fuel running past them and at an egual pressure. Hmmm, but is a fuel rail really any different to a manifold with four hoses running off it? Will probably give fuel rail a try - I was just worried about not getting it accurate enough for everything to line up Couldn't you have just put the throttle bodies the other way 'round if you wanted the injectors on top? Quote Link to comment Share on other sites More sharing options...
Burntrubber Posted July 5, 2007 Share Posted July 5, 2007 You will need a proper rail like Mikuni said and also I would try and stay away from hose tails if you can. I'm going to make a fuel rail to suit o-ring type eventually. Here's a pic hope it helps. Quote Link to comment Share on other sites More sharing options...
CaMpylobacter Posted July 5, 2007 Share Posted July 5, 2007 fuel rail wont air lock one injector, all pressures to injectors should be the same (with hoses, the regulator would be a fitfh hose off a 'distribution block' type setup) fuel rail should be easy enough too. you can buy the extrusion 'per metre', and work from there. Quote Link to comment Share on other sites More sharing options...
V8Pete Posted January 23, 2008 Author Share Posted January 23, 2008 Getting back into it after a bit of a break... So assuming I've decided to go rail, what are some of the ways of getting the injector holes if it's made of plate and tube? Is welding a wedge-shaped thing on (red bit below), then getting the holes machined the way to go potentially...or little, short bits of tube? Keen for suggestions/photos/MSPaints. Quote Link to comment Share on other sites More sharing options...
Mike-e Posted January 23, 2008 Share Posted January 23, 2008 get machined bosses to properly seat injectors then cut holes and weld bosses in, make sure bosses dont fuck with injector spray pattern slash not too long Quote Link to comment Share on other sites More sharing options...
V8Pete Posted January 23, 2008 Author Share Posted January 23, 2008 Are bosses basically = piece of tube? Quote Link to comment Share on other sites More sharing options...
Mike-e Posted January 23, 2008 Share Posted January 23, 2008 essentially yes, but more like a schedule 80 8mm nominal bore pipe with a step milled/drilled in it to seat the injector cushion Quote Link to comment Share on other sites More sharing options...
eke_zetec_RWD Posted January 23, 2008 Share Posted January 23, 2008 i machined mine out of solid with the steps to seal oring. i wud be careful squirting fuel at the valve head if it is a modified valve or narrow seats etc, the cooling effect against the hot valve head wont do it any good. Quote Link to comment Share on other sites More sharing options...
sentra Posted January 23, 2008 Share Posted January 23, 2008 yeah, with a provision for a seal. i tihnk you can buy weld in ones from vpw.com.au you want to measure the angle in regards to the flange the injectors want to sit, then just get the holes the the bosses need to sit in pitched off in a mill, specify it only needs to be set up with a protractor-level as the angle doesnt need to be very accurate($$) then get the holes in some extruded fuel rail pitched off to the same measurements. be sure to get them to cut a 2 diameter hole i.e the small hole through and the big one a shoulder cut to a specific depth. follow? if you walk in knowing exactly what you want done it will be cheap as. 1 Quote Link to comment Share on other sites More sharing options...
V8Pete Posted January 23, 2008 Author Share Posted January 23, 2008 Choice. Will draw some pics on the weekend to see if I'm on the right track. REckon it'll go mean? Quote Link to comment Share on other sites More sharing options...
Guest vvega Posted January 23, 2008 Share Posted January 23, 2008 yeah, with a provision for a seal. i tihnk you can buy weld in ones from vpw.com.auyou want to measure the angle in regards to the flange the injectors want to sit, then just get the holes the the bosses need to sit in pitched off in a mill, specify it only needs to be set up with a protractor-level as the angle doesnt need to be very accurate($$) then get the holes in some extruded fuel rail pitched off to the same measurements. be sure to get them to cut a 2 diameter hole i.e the small hole through and the big one a shoulder cut to a specific depth. follow? if you walk in knowing exactly what you want done it will be cheap as. yes i guess thats true and when you walk out and it dont fit or somethigns not rigth we charge you agina to fix your fuckup and then you pay more money...then yoru quick fix still isint right .....and by the time its all finished we coudl have done it our way for half the price yoru better off to go in explain what you want and let the engineers do it there way.takeit somewhere experanced because at teh end of the day everyone on the internet is a expert.... least that way if it dont work ...it wont cost you more cash to fix it i work in the custom crap industry ...and we now turn away people wantign to do it there way becuase 90% of them come back later becuase they have forgotton somethgin or its now not accurate enough just my experance from the 1000's of jobs ive done and been involved with of this nature Quote Link to comment Share on other sites More sharing options...
sentra Posted January 24, 2008 Share Posted January 24, 2008 i cbf getting into a debate on this. just measure everything properly remebering more clearance=lower tolerances=exponentially cheaper, think about intervening factors thougherly, think hard about how to describe what you want and you wont have a problem. i dont know if your giving me a hard time about being an 'expert', i dont proclaim to be one or anything but i do do this kind of shit day in day out so i thought it would be worthwhile saying something if anything to give someone the confidence to give it a go themself in a world of paying otherpeople to do everything and then putting a xyz motorsport sticker on your window. 1 Quote Link to comment Share on other sites More sharing options...
Guest sexychevette Posted January 24, 2008 Share Posted January 24, 2008 wats rong wif carbs? Quote Link to comment Share on other sites More sharing options...
V8Pete Posted January 25, 2008 Author Share Posted January 25, 2008 wats rong wif carbs? Too expensif Quote Link to comment Share on other sites More sharing options...
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