Single TBI on L20 in 620

[Orange620]

I'm looking at using a single Weber DCOE type manifold with a throttle body injector on on L20 in a 620. Does anyone have experience with a DCOE or equivalent sidedraft Mikuni in a 620? Will it fit in there with the brake booster and master cylinder?

 

 

[Cuts metal like mad]

your getting into uncharted territory as far as I know...

 

using a single injector to supply fuel for 2 cylinders is gonna be a head ache, you got a lot of homework to do... you can't just use an injector thats twice the size, and an injector sized for a single cylinder will be maxing its duty cycle... not good.

 

Good luck anyway.

[Z-train]

Two injectors for FOUR cylinders?Ain't gonna work.TBI is a joke.You will have no real gains over a properly working Webber DG or Hitachi.TPI is another story.

[Llittle_Llama]

i like the idea, looks CLEAN....but i think like Z-train it would be to much work. i dont have the expertise, but i understand the dynamics of it and yes, tuning would be a bitch.

[]2eDeYe]

It'll fit. Airhorn's will be real tight.

 

Phatdave has a single side-draft on his 620.

 

GM and Ford's TBI run 2 injector's for 8 cylinders...seems to work ok.

 

You'll have to figure out you injector sizing, for this application.

 

What's with all the negativity around here lately? :rolleyes:

[Orange620]

If I use those components with a megasquirt system, it looks like a fairly cheap/uncomplicated way to put fuel injection on an L20 engine.

 

The megasquirt FAQ webpage says most systems, even if they have port injectors are batch or bank fired and megasquirt sequential injection is still being developed.

 

http://www.megamanual.com/index.html

[Cuts metal like mad]

if you wanted to do TBI right, youd have to use a down draft setup just like the factory... :thumbsup:

[Cuts metal like mad]

If I use those components with a megasquirt system, it looks like a fairly cheap/uncomplicated way to put fuel injection on an L20 engine.

 

The megasquirt FAQ webpage says most systems, even if they have port injectors are batch or bank fired and megasquirt sequential injection is still being developed.

 

http://www.megamanual.com/index.html

 

I think you are missing the point, or maybe misunderstand how fuel injection works... :(

[Orange620]

I think you are missing the point, or maybe misunderstand how fuel injection works... :(

 

What is it you're saying, fuel injection has to be expensive/complicated or the Megasquirt webpage is incorrect? Are you saying almost all the megasquirt systems aren't batch or bank fired?

 

This is more of what it says:

 

fuel that is injected when the valve is closed doesn't go anywhere, it just sits near the valve vaporizing until the next time the valve opens (some OEMs deliberately squirt against a closed valve to improve vaporization). So squirting against a closed valve does not generally affect the AFR for that cylinder (though there may be a small effect on the combustion quality, good or bad, depending on the port wall temperatures, etc.)

the valve is generally effectively open (0.050") less 300

Edited October 12, 2008 by Orange620

[Orange620]

if you wanted to do TBI right, youd have to use a down draft setup just like the factory... :thumbsup:

 

What would be the advantage of that, the sharp 90 degree turn in the intake tract?

Edited October 12, 2008 by Orange620

[Cuts metal like mad]

no no no, the megasquirt info is correct... in TBI systems the injectors generally supply fuel for ALL cylinders not a pair, in a multiport configuration a single injector supplies fuel for a single cylinder, I'm not saying its not possible... just say your on your own as far as firguring out what size injectors to use and how to tune it... its not gonna be simpler than a multiport setup, less expensive in some ways yes, but will also make less power due to the TB supplying a limited amount of air in comparison to the amount of fuel the injection setup can supply...

 

There are cheaper and easier alternatives... not trying to deter you, but you asked for advice. Most people say that a single dcoe carb is crap... a weber 38 is a better option, so I would imagine the same limitations apply to a TB setup. I say why do an EFI setup when you lose so many of the benefits.

 

Go for it anyway though, would be cool.

[Orange620]

That throttle body has two true 48mm bores. Since they don't have venturis, they'll out flow even a 48IDA. However, performance isn't my goal, its putting the reliability and economy of fuel injection on an L20 engine.

 

From what I've read the JDM Nissan 200SX L18 fuel injection system doesn't even have an O2 sensor, so it doesn't sound all that great. I agree I'll be on my own figuring out injector size and settings, but I'm pretty confident that if I can get it sorted, those minimal components with a Megasquit controller will give me better reliability and economy than a carb.

Edited October 12, 2008 by Orange620

[datzenmike]

if you wanted to do TBI right, youd have to use a down draft setup just like the factory... :thumbsup:

 

Why so? I've seen TBI run upside down!

[Cuts metal like mad]

Why so? I've seen TBI run upside down!

 

your right, about that... reason why I say that was already stated, the manifold for the single sidedraft will use a single injector for 2 cylinders. Not the easiest to figure out. All the info out there is for MPFI, or "regular" TBI, that I know of... just haven't seen it done this way. I will say it again, its not impossible just more difficult.

 

I mean it might be possible with the megasquirt setup to double fire the injectors, since its a batch fire injection type you could probably connect both the 1-3 wires and 2-4 wires to both injectors therefore using the single injector as if it were two... just not sure if that would burn up the megasquirt, but I don't see why it would.

[Cuts metal like mad]

That throttle body has two true 48mm bores. Since they don't have venturis, they'll out flow even a 48IDA. However, performance isn't my goal, its putting the reliability and economy of fuel injection on an L20 engine.

 

From what I've read the JDM Nissan 200SX fuel injection system doesn't even have an O2 sensor, so it doesn't sound all that great. I agree I'll be on my own figuring out injector size and settings, but I'm pretty confident that if I can get it sorted, those minimal components with a Megasquit controller will give me better reliability and economy than a carb.

 

If your goin megasquirt you can use pretty much anything you want... it doesn't even have to be nissan... shhhh! :D Its your choice if you even want an O2.

[Orange620]

If your goin megasquirt you can use pretty much anything you want... it doesn't even have to be nissan... shhhh! :D Its your choice if you even want an O2.

 

 

I just mentioned the JDM L18 Nissan system in comparison as the only other option I've seen for putting FI on an L20. I'm not planning on using any Nissan injection components. It will definitely have an O2 sensor.

Edited October 12, 2008 by Orange620

[Fineline]

I mean it might be possible with the megasquirt setup to double fire the injectors, since its a batch fire injection type you could probably connect both the 1-3 wires and 2-4 wires to both injectors therefore using the single injector as if it were two... just not sure if that would burn up the megasquirt, but I don't see why it would.

 

Megasquirt can fire the injectors as many times as you want. It will also calculate the "total fuel" for your engine and adjust the pulse width of the injectors based on their size to run a certain AFR. All of the pameters are adjustable. You will notice a huge improvement over a carbureted setup. I can get close to 30+ mpg as long as I keep my foot out of it! But that is hard to do!

[Orange620]

Fineline, Do you have a megasquirt system on the 620 with the L22? What manifold/throttle body are you using? Do you have pictures?

Edited October 12, 2008 by Orange620

[Icehouse]

Orange620 The only thing I would be questionable about in this setup is which manifold to use. I once had a single side draft weber, the mani was a little different than yours, the runners crossed, I don't know what the benefit of this was but thought it was interesting. Damn the pic I have is the same one!! I remember on a old thread Kevin posting a pic of a different on.

 

 

 

That one is for a BMW, I'm sure you get the idea :D

[Fineline]

http://forum.ratsun.net/showthread.php?t=1816

[Fineline]

Orange620 The only thing I would be questionable about in this setup is which manifold to use. I once had a single side draft weber, the mani was a little different than yours, the runners crossed, I don't know what the benefit of this was but thought it was interesting. Damn the pic I have is the same one!! I remember on a old thread Kevin posting a pic of a different on.

 

 

 

That one is for a BMW, I'm sure you get the idea :D

 

That mani mould be perfect. You usually batch fire 1-4 injectors and 2-3. The crossover would work great. You could just wire the two injectors to fire opposite each other. If memory serves wasnt that how Ryaninseattle's Lynx manifold was made?

[Orange620]

On your recommendation, I just bought a Lynx manifold from Australia that was on ebay($120US). It does have the same crossover. I saw it a few days ago and wondered whether it was a better design than the Pierce(and cheaper). Thanks

 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWNX:IT&item=330278048116

 

Edited October 12, 2008 by Orange620

[Icehouse]

That mani mould be perfect. You usually batch fire 1-4 injectors and 2-3. The crossover would work great. You could just wire the two injectors to fire opposite each other. If memory serves wasnt that how Ryaninseattle's Lynx manifold was made?

 

Yeah thats what I was thinking! All the new L series mani's are junk if you ask me. The old stuff was just more thought out, since there is no money in L series like there used to be. The parts really show it! From what I have seen anyways.

 

Yep I think Ryan had the same mani if I remember correctly.

 

 

On your recommendation, I just bought a Lynx manifold from Australia that was on ebay($120US). It does have the same crossover. I saw it a few days ago and wondered whether it was a better design than the Pierce(and cheaper). Thanks

 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWNX:IT&item=330278048116

 

 

 

Have you ordered the TBI parts yet? make sure you post your results :D

[]2eDeYe]

If memory serves wasnt that how Ryaninseattle's Lynx manifold was made?

 

 

Yep.

[Orange620]

Have you ordered the TBI parts yet? make sure you post your results :D

 

Not yet. I'm going to get it from CBPerformance. I'll post.

 

http://cbperformance.com/catalog.asp?ProductID=412

 

 

Are there any good threads for putting a Z22 crank in an L20?