My Tempo EFI conversion

I think running two smaller ones would be good... yes you can make them opperate in sink off one TPS. and with two you can possition them more centeral to the cilanders, putting a simi-divider in the log carb opening and making two new holes on each side.
Those little TBs are ready to plumb since they have their own Hat. hook up the hose to a filter or a force induction device....Funny I have a pair of little turbos waiting for me to put then on something:)

I'm not anywere close to being sharp enought to build a MS by myeself so I will look for some help....but it looks like its do-able.

I did look at the 5.0 and 3.8 TBs.... I might swap out all my old carbed cars to EFI if this works....yippy...maybe not

Frank
 
Doing stuff like multiple (independant) throttle bodies or adding additional injectors to come on at rpm is mostly defeating the purpose of EFI in the first place. Thats thinking with a carb frame of mind.

The point of a fuel injection system is that it is able to meet all your engines needs with one system. An EFI system can deliver the right amount of fuel at idle and at 6000 rpm @ 20 psi. It doesn't need any special extra hardware to do so - You just need to set it up properly in the first place.

The whole point of the system is that the software has the ability to appropriately meter fuel in all situations. You don't need external devices to add fuel under boost or anything like that.

So all this crap about extra injectors or dual throttle bodies and everything else is applying a carburetion way of thinking to a fuel injected system - and what you get is the worst of both worlds.

That's one reason a LS6 can get 27 mpg on the freeway and 400 HP at the wheels.
 
Crap.. we arre talking TBI(they are crap in the first placeand cheap)...you still benifit with the injector being closer to the intake runners the ... so by dividing the intake and using two units non independant(they can be small) you would benifit. Not too different as a single two barrel TBI just split for distrubution benifits.

After all its alot easier to drill two carb mount type Holes than drilling and welding bungs for Tune port injection...after all you have to start somewhere... And to start I will try a single unit like Moes and Larry.

I like carbs... I know carbs. This will be a intro to Fuel injection for me. thuse I cant loose, I might fail but I will learn.

So to take IDEAS and call them CRAP is a little Lopsided from my point of view...nothing wrong with exporation....even if it is crap and being done buy performance and Hot rod companies as we speak.....

Might as well say why dont you just drop a Fuel injected V8 , or even a CHEVY...

I'm cool with it... I'm off to RadioShack...start collecting my parts...

Frank
 
Ian Moore,
a lot of really high HP cars are switching to two injectors per cylinder. Smaller injectors needed for good driveability can't flow enough at peak HP, and by the time you get an injector big enough to flow the fuel you need at peak HP, the ability of it to meter properly at idle is nil.


everything is a compromise.....even with EFI
 
linc I think the idea of twin TEMPO tbi's is that the injector in them can't readily be upgraded, it will bolt in place of a 1v carb, and will be able to supply enough fuel in a boosted app. but NA one of these is all we need.
 
Bort62":1hdx29om said:
Doing stuff like multiple (independant) throttle bodies or adding additional injectors to come on at rpm is mostly defeating the purpose of EFI in the first place. Thats thinking with a carb frame of mind.
Click to expand...

Nothing is absolute. The 13B rotary engine had two pair of fuel injectors. The primary pair was used for idle and up to mid-range rpms when the secondary injectors would then kick in. On the normally aspirated 13B it was timed to the opening of a pair of extra intake ports (commonly referred to as the 5th and 6th ports) that opened at a given backpressure from the exhaust. On the turbo cars (which only had 4 intake ports) the secondary fuel injectors were mapped to the amount of boost being delivered. Delivered an extremely smooth idle, lower emissions for the motor, yet could supply plenty of power at the top end. Extremely well thought out designs that worked well using "additional injectors". Not such a "crap" idea and really not at all like a carb.
 
The early Corvette Cross Fire was a dual TBI system as well....

But I'm not totaly you would have to add another TB or a second jet.
it might be more worth while to machine the jet opening to receive another style of TBI jet... maybe make a bung to slide into the opening...

Frank
 
Linc's 200":3q1p9gid said:
Ian Moore,
a lot of really high HP cars are switching to two injectors per cylinder. Smaller injectors needed for good driveability can't flow enough at peak HP, and by the time you get an injector big enough to flow the fuel you need at peak HP, the ability of it to meter properly at idle is nil.


everything is a compromise.....even with EFI
Click to expand...

You need to run into a REALLY big injector to have min pulsewidth issues at idle. I am not aware of any production vehicle that uses a multi injector scheme. That doesn't mean that there isn't, but it is hardly commonplace.
 
69Falcon":24pq4z8p said:
Bort62":24pq4z8p said:
Doing stuff like multiple (independant) throttle bodies or adding additional injectors to come on at rpm is mostly defeating the purpose of EFI in the first place. Thats thinking with a carb frame of mind.
Click to expand...

Nothing is absolute. The 13B rotary engine had two pair of fuel injectors. The primary pair was used for idle and up to mid-range rpms when the secondary injectors would then kick in. On the normally aspirated 13B it was timed to the opening of a pair of extra intake ports (commonly referred to as the 5th and 6th ports) that opened at a given backpressure from the exhaust. On the turbo cars (which only had 4 intake ports) the secondary fuel injectors were mapped to the amount of boost being delivered. Delivered an extremely smooth idle, lower emissions for the motor, yet could supply plenty of power at the top end. Extremely well thought out designs that worked well using "additional injectors". Not such a "crap" idea and really not at all like a carb.
Click to expand...

Of course nothing is absolute, but the 13B is an entirely different motor with a different set of needs. (primary among which a hugely different RPM band). It is an extreme case and hardly the norm. No one is going to build a ford 6 that winds to 9k but still needs to idle like glass at 600 rpm.

I have built a few and tuned a lot of fuel injection systems and understanding how the situation works is paramount to getting the most out of it. People have an old school way of thinking burned into their minds that makes them think they need to come up with all of these clever ideas. It's just not really the case 95% of the time.

It's the kind of thinking that makes people talk about "street tune" vs "Track tune". With EFI, its the same tune...
 
FrankBoss":1k7vf1f7 said:
The early Corvette Cross Fire was a dual TBI system as well....

But I'm not totaly you would have to add another TB or a second jet.
it might be more worth while to machine the jet opening to receive another style of TBI jet... maybe make a bung to slide into the opening...

Frank
Click to expand...


And the early (or any CFI) system sucked too. I've worked on a few - it's the laughing stock of GM fuel injection.

The only reason you would need to add additional throttle bodies to an EFI system is because you needed more CFM. In that case, the more appropriate approach 90% of the time is to use a larger TB. If you need more CFM on one of these heads and you decide to machine it to use two 1bbl tb's in parallel what you are really doing is just creating a 2 bbl tb. it's the same damn thing.. If you need more fuel than the stock tempo injector can handle, then why not just bite the bullet and move to MPFI?

Besides... TBI is less than ideal for performance any way you try to stack it.
 
No.

But once you run into the performance limitations of the TBI, your best bet is to move to mpfi instead of trying to hack some sort of weird multi TBI system together.

That's all.
 
just get a 4v converter and stick on the tbi from a 5.0 t-bird for a boosted app. that should get you the fuel you need. it is a dual injector TBI unit made for a seriously detuned 302, should be pretty good for a tweaked up 200, if you can control the fuel at idle from being too rich.
 
bort62 -- cmon man, this is the hole idea behind hot rods. Its your ideas that you designed and built. The twin tempo tbi's is a very unique idea, i would love to see it. after getting 2 tbi's on your intake log i dont think it would be too hard to make it work reliably. even with the added complexity its still easier than going to full on mpfi system. Either way, they are both cool ways to go about efi. I respect anyone who does either 8)

Also about the thing with injectors running to rich at idle because of the injectors minimum pulse width... couldnt you then just slowly bring down the fuel line psi untill it idles at like 12:1@minimum pulse width. That would be getting the maximum drivable performance ability out of your injector(s) right? Like if your running a huge injector @ 50psi and its too rich at idle, just step it down to like 48psi and see what your idle is like now, and so on... Is my thinking correct? If it is, its not like its hard to do especialy on the tempo tbi's since they have the freakin regulator built into them.
 
You are correct. You want to set your fuel pressure so that at idle you are running at somewhere just above min pulse width.

The problem lies when you are setup this way that at high RPM you hit 100% duty cycle on your injector/s and run out of fuel.

But - that's a pretty wild engine at that point. I've worked on a lot of fuel injected cars and the only ones that have had that problem have been 6-700 hp V8s. So you end up going to a bigger injector and your idle suffers.

But you are not going to have that problem with this setup.

And hot rodding is about doing what you want and expressing your opinions... and I am expressing mine. If you want to build an EFI system that works and doesn't waste a lot of your money, then you can listen to mine :)


If you want to tinker around and spend your money exploring your own ideas, go for it - but listening to experienced peoples advice is as much a part of hot rodding as anything else.
 
I should also add that I think the tempo EFI conversion is a great idea and I plan on basically following your lead on my ranchero. I hate carbs.

I've worked on a lot of EFI cars and built a few custom one-offs like this, but letting you do this first and figuring out all the details for me makes it a lot easier :)
 
And hot rodding is about doing what you want and expressing your opinions... and I am expressing mine. If you want to build an EFI system that works and doesn't waste a lot of your money, then you can listen to mine
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This is what i hate about the internet, I cant tell if your just telling us what you think or if your mad. Just to be sure, the thing i said about hot rods was ment to be friendly ok.

, but letting you do this first and figuring out all the details for me makes it a lot easier
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haha glad i could help :LOL:
 
ha, I don't get mad and post on the internet. That's like running in the special olympics.

At anyrate, I offer my opinions on these sorts of things for people to take or leave, and I only speak up when it is something I have a lot of experience with.

So take it, or leave it. :)
 
We first started talking about using the CFI about six years ago, but at the time there was no easy way to control it. Megasquirt had not been perfected yet and the stock electronics just would not work.

Since MS came about, this is a lot more feasible. Using CFI is a huge improvement over a carb, especially when coupled to ignition control. You can make very specific calibrations for specific VE, RPM, and loads over a wide range of conditions.

Adding CFI will provide several benefits: smoother idle, better cold/hot start, more power (due to more precise fuel metering), and improved fuel economy. With ignition management added, you can expect better overall driveability with better economy.

Where CFI/TBI falls short is in fuel distribution. It is still saddled with wet flow thru a manifold and unless the manifold is very well designed there could be some large variations in A/F distribution from cylinder to cylinder. Port injection addresses that.

In a log head, though, even going to port injection still has severe limitations because of the low airflow potential of the log manifold. You will improve fuel/air distribution, but cannot overcome airflow limitations.

In the case of the log, I don't think the marginal improvement in fuel distribution justifies the added cost and complexity of port EFI unless a new manifold system replaces the log.
 
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