Jesse OBrien Posted March 29, 2014 Share Posted March 29, 2014 I couldn't find a whole lot of hard info on the EV1 Cobra injectors, so I figured I'd start documenting myself here. Maybe some of you more experienced folk can point out some flaws in this plan that I don't know to look for yet. Initial Thoughts I got lucky and scored a set of 24# (~252cc/min) @ 42psi Cobra injectors off a friend. 252cc/min is technically a downgrade from the stock l28et injectors (~270cc/min @ 42psi), but let's address that later. They use the same electrical connectors, which is kind of convenient as well. Goals and Expectations The goal here is to get more efficiency, use more megasquirt-friendly injectors, and to clean up the clutter of the OEM fuel rail and those very odd-looking hoses that connect the rail to the injectors. High impedance injectors (like the EV1 Cobra injectors) are easier to wire into Megasquirt than low impedance injectors (stock Nissan), which makes my life a little easier (your mileage may vary). Those are my goals. Notice how I didn't mention power? Making 'big power' is not one of my goals. It's not even on the list of priorities. I want a car that I can drive the snot out of and an engine that doesn't break down, and is easy/cheap to fix when it does. Anything over 200whp is absolute gravy, and at that point I'm just going to be tuning for the best powerband, most efficiency, and most rock-solid reliability possible. Give me a fun car I can drive every day, and everything else in life just falls into place. By moving toward a more widely accepted standard, I'll have better injector upgrade options, better documentation, and lower prices (a set of 36#/378cc/min injectors goes for roughly $100 lightly used - capable of supporting roughly 400hp with the right tune/combustion). I'm making several power assumptions that are based on this calculator as a reasonably accurate starting point: http://clean.injectorrx.com/fuel-injector-calculator/ Technical Information The old injectors have a complicated mounting system with a threaded manifold bung, a seat, several washers, and phillips-head screws that are IMPOSSIBLE to remove after 40 years of rusty neglect (I had to cut off 8 of the 12 machine screws, and managed to remove the studs for all but one - which still lives in the manifold). The upper and lower orings are both 14mm diameter, which absolutely requires a new fuel rail (Pallnet exceeded my expectations and got it out more quickly than I had expected - I should be able to pick it up at USPS tomorrow). I mocked up the injectors on an n42 manifold I had lying around: While that looks fine at this angle, it really isn't. The lower 14mm orings don't slip into the manifold bungs, and therefore won't seal. They also won't spray against the rear-side of the valves, which is no good. I see no alternative but to take the intake manifold to a machinist friend and have her help it out by opening up the injector bungs. I'm going to try to mimic the seating angle/depth of the original injectors as much as possible, but the fact that I'm going from a single-hole fuel squirter to a 4-hole fuel sprayer might throw a wrench into the works. I don't really have any experience to draw upon, so I'm just going to dive in with both feet and try to put some data together. In theory, the Pallnet fuel rail should apply pressure to the backs of the injectors and hold them in place. I see no reason to use the tapped holes in the manifold for extra pressure: most manufacturers have been using a rail to secure the injectors since the 90's. That's all I have for right now, I'll meet up with my machinist/welder friend tomorrow and see what she has to say about the job (it sounds like a fairly straightforward milling job), and pick up the fuel rail to do some more accurate mockups of what I have to work with while I'm at it. Quote Link to comment Share on other sites More sharing options...
Ryan Merrill Posted March 29, 2014 Share Posted March 29, 2014 Actually I believe that the bue injectors are 39's and the green tops old style are 42's. Quote Link to comment Share on other sites More sharing options...
AkRev Posted March 29, 2014 Share Posted March 29, 2014 First off, I am not trying to discourage out of the box thinking in anyway. I do have a few thoughts and concerns about the spray pattern of your EV1 with single intake valve engine. If you look at the spray pattern of the EV1 (https://www.youtube.com/watch?v=Zu25-ObPUGM) it appears to me that it is designed for a 4 valve head. I understand that the spray is a better atomisation, but does the increase of wall saturation actually decrease efficiency? However, without first hand experience with the injectors, I have no idea if the spray angle would even be great enough to cause the increase in wall saturation or if the injector is mounted close enough to spray at the ideal spot. Hopefully, someone that has ventured into this territory could give some feedback on this, as I would like to know for myself too. Thanks for taking the time to post your adventures. Quote Link to comment Share on other sites More sharing options...
Jesse OBrien Posted March 29, 2014 Author Share Posted March 29, 2014 Actually I believe that the bue injectors are 39's and the green tops old style are 42's. I'm not sure, and don't have access to a flow bench to verify. It may be worth sending them out to get cleaned and tested, but I can't do that right now. My friend said they were 24# when he shipped them to me, but 39# would work great as well. Wikipedia appears to agree with that, but I can't verify that these actually came out of a Cobra Mustang either. http://en.wikipedia.org/wiki/Ford_Mustang_SVT_Cobra#Engine First off, I am not trying to discourage out of the box thinking in anyway. I do have a few thoughts and concerns about the spray pattern of your EV1 with single intake valve engine. If you look at the spray pattern of the EV1 (https://www.youtube.com/watch?v=Zu25-ObPUGM) it appears to me that it is designed for a 4 valve head. I understand that the spray is a better atomisation, but does the increase of wall saturation actually decrease efficiency? However, without first hand experience with the injectors, I have no idea if the spray angle would even be great enough to cause the increase in wall saturation or if the injector is mounted close enough to spray at the ideal spot. Hopefully, someone that has ventured into this territory could give some feedback on this, as I would like to know for myself too. Thanks for taking the time to post your adventures. I agree that it appears that way, but the engine these were designed for is a 4.6/5.0 pushrod v8. Again, I'm working on a bunch of assumptions here and won't KNOW anything until I've done some testing. Looking at the spray tests I've seen (like yours, just youtube videos), I don't think it'll be too much of a problem as long as I can get the injectors close enough to the back faces of the valves. In any event, I have a hard time thinking these will be worse than stock. If they are, I simply keep searching for a better common design. Quote Link to comment Share on other sites More sharing options...
AkRev Posted March 29, 2014 Share Posted March 29, 2014 Good luck with your machinist/welder friend today. Quote Link to comment Share on other sites More sharing options...
NewZed Posted March 29, 2014 Share Posted March 29, 2014 (edited) Unless you're injecting in sequential mode, back-of-the-valve targeting isn't really significant, from my learnings. Only one intake valve will actually be open per injection event in batch mode, two in semi-batch. Apparently, even good vaporization out of the injector isn't that significant either, except for emissions purposes. That's why the primitive Nissan injectors (from Denso or Nippon-Denso?) shoot a narrow stream even though the Bosch design of the time, that they're based on, sprayed a cloud. Just some thoughts. It looks great in the minds eye to see a cloud of fuel vapor thrusting past the intake valve to do its work. But it doesn't seem to add up to much, in reality. I learned most of this from a French model on the internet, Beware. Forgot to say that I've had a set of Bosch injectors (028 150 116), that sprayed a nice big beautiful cloud of vapor, on my stock 1978 L28 and EFI system, and a set of original 1978 Nissan injectors, that sprayed a tiny jet stream of fuel, and they ran and idled essentially identically. That's why it's in mind. I built a flow tester to test flow rates, leakage, and see injection form. Results were kind of disappointing, but kind of comforting also. One less thing to be concerned about. Edited March 29, 2014 by NewZed Quote Link to comment Share on other sites More sharing options...
Jesse OBrien Posted March 29, 2014 Author Share Posted March 29, 2014 NewZed, it's good to have a little first-hand experience here, rather than just my fumbling around in the dark. I had suspected that this project is a waste of time as far as efficiency/performance, but I'm still pursuing it - if only for parts availability and to finish what I've started. The Pallnet rail came in, and fits beautifully as a mockup. I'm still pretty unhappy with the injector/manifold mating, as the oring doesn't sit IN the intake manifold. I can only imagine this will cause issues for me, especially if I ever want to increase my fuel pressure. I think it should sit roughly 1" deeper in the manifold, and the injector outlet would end up roughly where the stock injector outlet was, relative to the intake valve. You can actually see the oring sitting on top of the intake manifold's injector bung here: My machinist friend said she'd be happy to enlarge those holes to accommodate the orings, and it feels like the Pallnet rail is designed to have a bit more torque on the brackets. If not, it'd be pretty straightforward to adapt his design to move the rail a little closer to the injector bungs. For better or worse, this plan is coming together nicely. Quote Link to comment Share on other sites More sharing options...
AkRev Posted March 30, 2014 Share Posted March 30, 2014 Looked around a little bit, found some interesting info on this thread. http://forums.hybridz.org/topic/85340-intake-manifold-porting-and-injector-upgrade/ Also found another good read here. http://www.hotrod.com/pitstop/hrdp_0704_pitstop_fuel_injector_location/ Nice fuel rail by the way. Quote Link to comment Share on other sites More sharing options...
Jesse OBrien Posted March 30, 2014 Author Share Posted March 30, 2014 Looked around a little bit, found some interesting info on this thread. http://forums.hybridz.org/topic/85340-intake-manifold-porting-and-injector-upgrade/ Also found another good read here. http://www.hotrod.com/pitstop/hrdp_0704_pitstop_fuel_injector_location/ Nice fuel rail by the way. Really helpful. I hadn't really dug through the archives as hard as I could have, but that's exactly what I would've been looking for. It sounds like it doesn't really matter where my injectors are, so I'm just concerned about getting them to seal. In the interest of simplifying everything, I'm making a big push to get this manifold wrapped up this week to install next weekend and finally start the thing up. Quote Link to comment Share on other sites More sharing options...
mattb3562 Posted March 31, 2014 Share Posted March 31, 2014 Are you planning on deleting your pcv or relocating? You'll probably need to move it forward for a larger turbo compressor. If thats in the future... Also, I made my own fuel rail and made the adjustment where I can get it pretty tight with just the manifold bolts and then really pull the rail down towards the manifold with the bolts that go into the bottom of the rail. Quote Link to comment Share on other sites More sharing options...
Jesse OBrien Posted March 31, 2014 Author Share Posted March 31, 2014 Are you planning on deleting your pcv or relocating? You'll probably need to move it forward for a larger turbo compressor. If thats in the future... Also, I made my own fuel rail and made the adjustment where I can get it pretty tight with just the manifold bolts and then really pull the rail down towards the manifold with the bolts that go into the bottom of the rail. Pallnet's mounting brackets seem to do a great job, I just need to stop trying to stuff a 14mm component into an 11mm hole. Right now, I'm actually going to a SMALLER turbo. I got a great price on a .48 t3 that's in great condition, and I'll sacrifice a little size in order to have a more reliable, trustworthy machine. Eventually, I may go to an upsized compressor, but that's a season or two away - I'd much rather get the most out of a low-powered engine and solve the PROBLEMS with the car rather than trying to improve things that don't yet need improvement. I'm just going to run a catch can in place of the PCV system. I can't think of a downside to that, and catch cans are pretty dead simple to build (or ebay). Quote Link to comment Share on other sites More sharing options...
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