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Another way to mix fuel and air


HoustonZ

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BTW, Megasquirt will run staged injection. One bank of injectors on IJN1 and another bank on INJ2 with the Dual-Map code available. Turn one set off at X rpm as the others come on slightly before that. Seamless transition. Lets you use the stock injectors for stock idle and transition into low boost (or up to 3500rpms) and then larger injectors for on upwards in the RPM range and/or higher boost ranges.

 

"Dual Table Fuel"? It's been a while...

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To start out:

I'm sorry again Tony. Just having some communication difficulties. I'm trying to go off of your previous posts so you don't feel like you have to spoon feed all the time and also so you don't feel like people are ignoring your words of advice.

 

The .030" reference:

http://forums.hybridz.org/index.php/topic/63445-making-my-own-efi-intake-the-first-casting/page__view__findpost__p__693672

Once the throttles are cracked more than maybe 0.030", you are TOTALLY dependent on the angle of the throttle plate for airflow synchronisation. nothing you can do with a bypass will have any great effect.

 

ECU reference:

http://forums.hybridz.org/index.php/topic/95308-bsr-gtu-e31-head-images/page__view__findpost__p__901002

TWO computers, one controls the first two sets, and the third runs a totally different computer which is totally RPM / Boost / Throttle Position based. Ignition timing is handled by the first computer through the whole RPM range.

 

Grape Ape Racing reference:

http://forums.hybridz.org/index.php/topic/86498-engine-temperature-tests-and-results/page__view__findpost__p__826391

You need to go to the grapeaperacing site and read the information on cooling there, this will make it crystal clear why spot boiling will cause a runaway thermal situation in an engine.

 

 

I'll do my best to post a link since there is a lot of chatter in other threads I'm pulling from. Sorry about any wrong inferences too. I'm trying to make an educated decisions based on whats given to me. If its wrong, its probably because I haven't revealed "the next step". There will be the inevitable error in my logic until I fully learn. After doing a CTRL + F >>> "tony", there was the one initial error which I already took care of and everything else according the posts I pulled from, are all true recollections.

 

I'll come back after I read the rest that you have posted.

 

EDIT:

I think I'm just getting confused with the whole IAC thing. I understand the synchronization and master idle adjust process now though. What I will do is seat the throttle plates as best as possible to ensure a good consistent seal on the runner walls and go from there. Even if it runs like crap at idle, I probably won't even care unless it's a serious problem.

 

From the looks of things it seems that it could be more advantageous to utilize the holes for a balance pipe rather than idle control, until there is a known problem with idle that must be addressed. Considering that after a slight crack of the throttle plate, the air bleeds won't be of much help but a balance bar would be:

On my turbo car, I could feel individual cylinders hit during hard acceleration when I didn't have a balance tube. AFter I installed one, I had some trouble checking synch unless it was disabled, but the power was MUCH smoother under acceleration than it had been with the non-balance tube setup.

Edited by josh817
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BTW, Megasquirt will run staged injection. One bank of injectors on IJN1 and another bank on INJ2 with the Dual-Map code available. Turn one set off at X rpm as the others come on slightly before that. Seamless transition. Lets you use the stock injectors for stock idle and transition into low boost (or up to 3500rpms) and then larger injectors for on upwards in the RPM range and/or higher boost ranges.

 

"Dual Table Fuel"? It's been a while...

 

 

I understand that MS can do staged, just never seen anyone use it. My concern would be running 6 injectors on one driver. Possible, but pushing the limit of what those drivers can do. If people are using staged with success, good for them. On my Wolf system it has two extra drivers for batch fire.

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Yes you are thinking of it 'wrong'. :P

 

Think of the Ford or GM TBI setups and tell me how they differ from the F1 setup...other than the horsepower. How does that setup get air to run the engine? There is an IAC on there, but it's admitting air nowhere near where it will allow fuel to mix into it's bypass of the throttle plate...

 

Even using a stock SU body and closing the throttle and spraying a 1000cc injector to the top of the wall where the tau layer forms...it STILL idles fine. I don't know how, and I swore it would never work... but it did. I changed my thoughts about how closed closed throttles really were after that eye-opener.

 

And propped-open throttles is a relative thing. I don't think F1 idles that low. That would be like our engines idling at 250 to 300 rpms. You don't need much of an opening to allow an engine with really well atomized fuel to idle.

 

The head placement of the injectors is purely emissions-driven. Performance applications move it from there, further upstream when practical to do so. And the plates as close to the valves as possible for throttle response.

 

This makes the air door function very crisp, and if you have a large layer of fuel wetting the manifold it responds to transients better. But I digress...

 

Sorry its taken me a while to get back to this. Tony, that makes sense and I'll buy that it will probably work (IF YOU SAY SO :P ). Like I said, I haven't tried this, and its a bit counter-intuitive.

 

I was thinking more of an L6 idle speed with this setup when I said 1800rpm.

 

One other thing to consider if you are thinking about injecting at or above the horn is that while it should work fine for a naturally aspirated setup, you would want to be careful it doing this in a plenum for forced induction (or a cold air box for that matter). If you have an asymmetrical plenum like most of us, the air flowing past the front cylinders can have an effect on the fuel fuel delivery and wreak havok with your mixtures. I believe I saw an example of this on the extrudabody posts or their website, can't remember...

Edited by TimZ
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The 030" is referring to idle versus 'running'... NOT setting idle! Not even close to what was being discussed here. I have ALWAYS referenced 0.003" intital setting of ITB's for idle flow synchronisation. Why am I so adamant about that number? Because that was what I started doing after Gene Berg showed me the way to set up carbs when you don't have a synchmeter. Doing it his way got me making little or no adjustments following his lead and example. Since then, this is the way I have always set things up. The 0.030" was discussing when the synchronization AT IDLE no longer matters. It referred in NO WAY to setting the idle! Christ, 0.030" will give me probably 5-6000 rpms free rev, and likely 45mph loaded in gear cruising!

 

Two computers? Please stick to related items. This is the issue with people talking theory. Just because it's applicable in theory for one application....doesn't mean it's applicable or even warranted in another.

 

Spot Boiling is totally unrelated to anything discussed here.

 

Want me to make it clearer: Next person that posts "Tony Said" without SCRUPULOUS LINKS AND DOCUMENTATION OF RELEVANT SUBJECT MATTER will see me report the thread to a moderator for removal of the item. Don't say 'Tony Said' ESPECIALLY when I didn't say it.

 

You're 'recollection' is correct only in the fact that the words were out there in some semblance of order. Their applicability to this discussion is tenuous, if not totally irrelevant. ESPECIALLY in the context in which they were subsequently referenced.

 

Don't quote me when you aren't quoting me.

 

:angry:

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I understand that MS can do staged, just never seen anyone use it. My concern would be running 6 injectors on one driver. Possible, but pushing the limit of what those drivers can do. If people are using staged with success, good for them. On my Wolf system it has two extra drivers for batch fire.

 

 

It is more prevalent on the guys running 4 bangers. The system was designed originally for V8 Chevys, and the drivers are more than robust enough for dual table operation of four injectors.

 

Now, Throttle Body systems with 4 injectors on a 6 cylinder..... :P

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BTW, for reference from the first thread referenced as an example for "0.030":

 

"Then, once they are seated (which should starve the engine or have it operating WELL below target idle speed... some people set them arbitrarily at 0.003" open with a feeler gauge on a bench-setup before installing them---that was a Carburettor specification and can not be applied to EFI. Frank 280ZX tried that with his ITBs and got an engine that was idling at 2500rpms! "

 

Nice try, but read the thread and comprehend it's many facets before picking and choosing what you want to use from it!

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Honestly I was fixing to post "You're right Tony. Can we move on now?" until I saw how you not only want to prove a point but you also want to make look like a buffoon. Hopefully you're up for some reading.

 

"Ehh Tony, I still don't think we are on the right page and you're getting flustered (rightfully so if I was doing it wrong). My point with the .030" of cracked throttle was EXACTLY what you are saying! You will be far from idle, after the slightest crack and the tiny 1/32" orifice from the air bleed (if it was fully open) that I was going to use, becomes useless at that point.

If I don't care much about idle, and if after a very minute gap of a cracked throttle (Tony said .030" maybe) the air bleed sync's are moot, would one even need them?

The 0.030" was discussing when the synchronization AT IDLE no longer matters.

Well that sounds familiar. You just said it for me again.... because we're on the same page. However my wording was a bit confusing, making it sound like I wanted to tinker with idle by opening the throttle plates. That's not what I meant, my point there was that the car won't be street driven and idling isn't something it will do often. What I'm getting at is, unless if my air bleed idea affects the entire RPM, then I will choose not to use it. In no way am I saying set the idle by cracking the throttle. Luckily I cleared that one up AND apologized for my weird wording WITHOUT freaking out.

 

The interesting tidbit here is that this thread is very similar to the thread I pulled your quote from, both discussing staged injection, can it be done, how can it be done, etc, theories should be freely exchanged. Wow, we were even discussing whether an injector spraying onto a closed throttle plate would still work fine, in that other thread. The similarities are astronomical! Actually the one dissimilar thing is when I kept questioning whether it would work you YET AGAIN went off on a tangent but in this thread when someone other than myself does the same, you're so calm. Maybe you had a bad day.

 

But for the sake of pushing aside USELESS argument, I'm just going to say yes you're right Tony because in the end that's what you want to hear. I will however post our quotes side by side, actually on top of one another in case there is a problem with that wording, for easy analysis. I even added surrounding text for those who are questioning the legitimacy of like topics.

As far as MS is concerned, I'm definitely no expert on it so chances are I'm wrong but I remember seeing a picture of the screen from somewhere about it. A quick search also yielded results for like dual tables perhaps for methanol injection use. Or even like Tony said a while ago about having 2 ECU's so after a certain RPM the other one starts controlling another set.

The secondary injectors on there are because TWM is mounting supplemental injectors for higher rpm usage. Or for methanol injection. Or for whatever reason. I know people with a set of 370CC injectors at the head which runs from idle to 3000rpms. Another set of 550CC injectors that run from 3200 till fullboost and to around 6000rpms. Both sets shut off at 7000.

 

That's when the third set of 1100's kick in for the trip to redline.

 

TWO computers, one controls the first two sets, and the third runs a totally different computer which is totally RPM / Boost / Throttle Position based. Ignition timing is handled by the first computer through the whole RPM range.

 

As for the Grape Ape thing, indeed it was in a TOTALLY different topic but if you took the time to see how I typed... I'll provide you with the reference in case you are unable to go to page 1 and scroll up/down for whatever reason (maybe you're on a phone):

I think when I crunched the numbers, using some Camaro website Tony had mentioned a while ago (http://www.grapeaperacing.com/tech/index.cfm)

We can see that you were being credited for providing a very informative resource. However, it appears you are either getting tangled up in your rage or you just want to argue over "what does coolant have to do with this" so in that case I could just as well remove your name. Done.

 

Give a thank you, receive a shut the hell up.

 

*takes a breath*

 

Can we move on now? I'd really like to learn more about this stuff."

Edited by josh817
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As long as the 'Tony Said' references stop, we can move on, positively.

 

Note, the 0.003" was referenced as a 2500rpm point on an EFI ITB setup... just for pedantry's sake...

Edited by Tony D
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I went to "high butterfly" stacks on my 914/6 2.7 euro compression ratio engine with rsr cams and the engine put 255hp to the wheels.

 

It actually seemed to help throttle response with the butterfly's further away from the ports but that engine was a pretty extreme example.

 

The location of the throttle plate has be figured into the "big picture" when you are considering stack length and cam timing.

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  • 4 weeks later...

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