zedman280 Posted November 21, 2011 Share Posted November 21, 2011 Question: How big of an injector can the stock ECU handle ? I've already upgraded my fuel pump and fpr. Just wondering, can I go 330 cc on the stock ECU ? If I missed a post on it, I slap myself in the face now. I did see the sticky on fuel inj, but nothing about max size on stock ecu! Cheers and thanks Quote Link to comment Share on other sites More sharing options...
letitsnow Posted November 21, 2011 Share Posted November 21, 2011 The stock ECU can control the stock injectors. My stock injectors flowed ~300cc/min after I had them cleaned, I think they tested at 43.5psi. Quote Link to comment Share on other sites More sharing options...
kolonelklink87 Posted November 21, 2011 Share Posted November 21, 2011 The stock ECU can control the stock injectors. My stock injectors flowed ~300cc/min after I had them cleaned, I think they tested at 43.5psi. Question: how is it acceptable to increase fuel pressure but not acceptable to increase injector size? I've never bothered to mess around with the stock ecu as aftermarket units are much more tunable but out of curiosity it seems the net effect would be the same. A greater pressure differential = more flow right? So why would it be okay to run the stock injector at greater than stock flow rates but not an aftermarket injector of comparable flow ASSUMING you correct to circuit resistance appropriately? -pete Quote Link to comment Share on other sites More sharing options...
letitsnow Posted November 21, 2011 Share Posted November 21, 2011 It would still run rich with higher pressure, there's no difference. If you used a rising rate fpr, then it only runs higher pressure in boost. Quote Link to comment Share on other sites More sharing options...
zedman280 Posted November 21, 2011 Author Share Posted November 21, 2011 Well said !! Perhaps I modify my question. My plans for now are likely 250 - 300 crank hp. Can the stock L28ET injectors safely handle that hp range ? Someday I plan on looking into and installing an after market ems, but for the time being just want to get her back together and start enjoying her (hence spending money on an after market higher flow injector now, that I can likely still use in the future with increased hp goals) Quote Link to comment Share on other sites More sharing options...
kolonelklink87 Posted November 21, 2011 Share Posted November 21, 2011 (edited) So why can't the OP swap his injectors? I mean... it would probably be prudent for us to ask why do you think you need bigger injectors? But aside from running rich as dogs breath because of choosing the wrong injectors (bigger ain't better) it seemed you were implying there was a practical limitation to the ECU driving alternative injectors. zedman... what are the full details of your motor (head/block/turbo/ecu/FP and pressure) and what evidence do you have to suggest you need aftermarket injectors (AFR's detontation or anedotes)? Cheers, -pete *edit* It sounds like snow would be more qualified to answer this question an I but I don't think stock L28et injectors should not be a hindrance to you running that HP. Edited November 21, 2011 by kolonelklink87 Quote Link to comment Share on other sites More sharing options...
letitsnow Posted November 21, 2011 Share Posted November 21, 2011 (edited) He could, but he'd be running ~22% rich. The stock injectors should be close to maxing out at that point, assuming no increase in pressure. I've seen 50ish% duty cycle on my 750's(at a lower pressure, probably closer to 600-650cc) with the stock turbo at 12-14psi(intercooled, full exhaust, etc, probably close to 250rwhp), so that's pretty close to the limit for the stock injectors. I'm not that well versed in making the stock ecu work at higher power levels, but I believe people make them work reasonably well with rising rate regulators. Edited November 21, 2011 by letitsnow Quote Link to comment Share on other sites More sharing options...
zedman280 Posted November 22, 2011 Author Share Posted November 22, 2011 My plans, set up: I just rebuilt the L28ET, all new parts, honed block, fresh rebuilt p90a head, 3 angle valve grind, new cam, seals, etc, etc, etc. L28ET ecu, afm, dizzy, etc Stipped intake manifold, 300zx throttle body (intake match ported), stock turbo exh. manifold, bosch jetronic fuel pump (from an 80's 535 bimmer), adjustable fpr, lightened flywheel, electric rad fan, msd 6 ign and coil. Haven't decided on a turbo or intercooler yet (will likely go with the SIMTEC MOSPORT intercooler-- to replace the old bosch unit I had once scrounged from the wrecker), and a manual boost controller. All very basic, for now. I plan on upgrading in the future, which is why I asked about bigger injectors, don't want to buy things twice. I was running the same set up above (with stock turbo) on a non turbo L28E motor in the car prior and was safely pushing about 9 psi (but the engine had over 400,000kms on it and was time to be rebuilt, which is when I scored the complete L28ET !). Quote Link to comment Share on other sites More sharing options...
letitsnow Posted November 23, 2011 Share Posted November 23, 2011 You might want to consider moving away from the stock ecu in that case, it doesn't really like bigger cams and bigger turbos. Quote Link to comment Share on other sites More sharing options...
Gollum Posted November 29, 2011 Share Posted November 29, 2011 You can manage to get away with a slightly different turbo, but changing to even a slightly different cam will throw your tune off by a good margin. You've obviously put a decent amount of work into this car, I'd suggest just going megasquirt at this point. Considering that you should have a wideband ANYWAYS, MS will only add an extra $500 or so to your budget. Probably the best $500 you could ever spend. In all honesty one of the main reasons my car isn't on the road right now is because fighting stock EFI issues has me weary, so I'm waiting for the funds to do it right. In the meantime I'm doing what I can to rewire my chassis from scratch. There ARE people who've made amazing power with the stock EFI. There's also quite of a few of those people that switched to megasquirt eventually and marked notable improvements in just about EVERY aspect. The engine will operate smoother, crisper throttle response, more power through the range, better economy, etc. It's really hard to justify using the OEM ECU unless you're running a close to OEM setup and that's all you expect to get out of it. Quote Link to comment Share on other sites More sharing options...
zedman280 Posted November 29, 2011 Author Share Posted November 29, 2011 Good to know guys, I figured with a mild cam I'd still be able to get it to run, great info. That being said, I've never looked into Megasquirt, only SDS, and didn't really want to spend 1200 bucks. I've seen some info here on the MS system and the links to the MS website. Is there a specific install thread here on hybridz on what's needed, etc ? I have some ECU tuning knowledge (started playing with my saabaru using ROM RAIDER and a ***-com cable), but not enough and clearly need more practice/ info. I like the sound of 500 bucks, so any info or points in the right direction would be greatly appreciated ! thanks all Quote Link to comment Share on other sites More sharing options...
macambra Posted November 29, 2011 Share Posted November 29, 2011 Good to know guys, I figured with a mild cam I'd still be able to get it to run, great info. That being said, I've never looked into Megasquirt, only SDS, and didn't really want to spend 1200 bucks. I've seen some info here on the MS system and the links to the MS website. Is there a specific install thread here on hybridz on what's needed, etc ? I have some ECU tuning knowledge (started playing with my saabaru using ROM RAIDER and a ***-com cable), but not enough and clearly need more practice/ info. I like the sound of 500 bucks, so any info or points in the right direction would be greatly appreciated ! thanks all DIYautotune has an install document on their website. http://www.diyautotune.com/tech_articles/how_to_megasquirt_your_280zx_turbo.htm Quote Link to comment Share on other sites More sharing options...
zedman280 Posted November 30, 2011 Author Share Posted November 30, 2011 Thanks for the info. I'm a dummy, shortly after I posted I found more info in the FAQ section, but then my baby woke up, so had to go !! Thanks all ! Quote Link to comment Share on other sites More sharing options...
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