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Anonymous
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how about a a boost sensitive timing retarder and water/alchohol injection set to turn on when u reach whatever RPM the turbo spools up at?
TBI
- Thread starter ski4evr
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Anonymous
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I gotta bring this topic up again...could i pull the computer stuff with the TBI out of a tempo or taurus or whatever and just get larger jets (or similar) to compensate for the lack of fuel, since its off a 4 banger would i be running extremely lean or extremely powerless with the stick setup...also is it possible to get the computer changed at a shop to feed 6 cylinders rather than 4...i really dont want to mess around a whole lot with this...mostly just to swap in the setup...maybe change the jets to bigger ones and muck around with wiring, elec fuel pump and fuel return line....i never saw a price 4 the megasquirt...is there one on the site or did i miss it? also for a fuel return line...would it be fine to drill a hole and use a rubber grommet for a nice tight fit around the metal line?
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Anonymous
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MegaSquirt is around $150.00 for a (build it yourself) kit. and people are selling assembled kits for $250 or so.
Three TBIs, don't think it is a viable prospect.
There remains the problem of difference of flow in the log manifold all cylinders are not equal, no matter how it is divided or modified short of cutting off and replacing.
How would each TBI unit be tuned to match flow rate of each pair cylinder being feed? O2 sensor in header tubes matching? Gets complex and complicated.
A single TBI unit would work because air/ fuel is measured and mixed prior to entering log so the air/ fuel ratio would be correct no matter what the intake flow efficiency of any given cylinder.
There remains the problem of difference of flow in the log manifold all cylinders are not equal, no matter how it is divided or modified short of cutting off and replacing.
How would each TBI unit be tuned to match flow rate of each pair cylinder being feed? O2 sensor in header tubes matching? Gets complex and complicated.
A single TBI unit would work because air/ fuel is measured and mixed prior to entering log so the air/ fuel ratio would be correct no matter what the intake flow efficiency of any given cylinder.
twentyover
Well-known member
Thad-
Think you're making it more complex than it really is.
First, there is no requirement that you split the manifold- and I'm not convinced there is significant enough gain to make it worthwhile. Not based on data, based on unsupported opinion. Just drop the throttle bodies on the manifold- set up a synchronized linkage, and you're good to start filling in the tuning tables. If the end cylinders don't get exactly the same volume fill, is it any worse than the single point induction, either carb or throttle body?
When not tuning for emissions, there is a fairly large range of acceptable air/fuel ratios that can be safely run- if a couple of cylinders aren't exactly right- well, are you sure that all 15 million cars sold by automakers each
year don't have any variation between them?
If a single oulet header, put the Ox sensor in the collector, if a dual outlet parallel two ox sensors or use just one and blow the second one off.
And i don't share your optimism that fuel and air are completly homogenized and don't seperate as it makes 2- 90 degree turns in the manifold before entering the port.
My favorite idea, as I've previously noted, is to use six port injectors in, you guesed it, the ports, and use three dryflow throttle bodies on the log. Minimal chance for separation as the heavier fuel doesn't need to turn (many) corners.
Think you're making it more complex than it really is.
First, there is no requirement that you split the manifold- and I'm not convinced there is significant enough gain to make it worthwhile. Not based on data, based on unsupported opinion. Just drop the throttle bodies on the manifold- set up a synchronized linkage, and you're good to start filling in the tuning tables. If the end cylinders don't get exactly the same volume fill, is it any worse than the single point induction, either carb or throttle body?
When not tuning for emissions, there is a fairly large range of acceptable air/fuel ratios that can be safely run- if a couple of cylinders aren't exactly right- well, are you sure that all 15 million cars sold by automakers each
year don't have any variation between them?
If a single oulet header, put the Ox sensor in the collector, if a dual outlet parallel two ox sensors or use just one and blow the second one off.
And i don't share your optimism that fuel and air are completly homogenized and don't seperate as it makes 2- 90 degree turns in the manifold before entering the port.
My favorite idea, as I've previously noted, is to use six port injectors in, you guesed it, the ports, and use three dryflow throttle bodies on the log. Minimal chance for separation as the heavier fuel doesn't need to turn (many) corners.
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Anonymous
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steell":1dkq4qhx said:
Really? wow...ok...i was thinking closer to like $600-800....that looks a little more promising....so i may actually try that than....but any word on if the injectors will be sufficient...could the megasquirt be setup to squirt more fuel or will the injectors need replacing...and i hope i'm not repeating a question that was already asked somewhere....I just want a single TBI..something a bit more efficient on fuel and is fairly unique...I am thinking the setup will cost about $500ish cdn when its done...is that about right...i will be (hopefully) starting a new job at a tire shop so i will be getting larger checks and can finally afford some stuff...although I may not have time if i think about it now to do too much since its my daily driver work vehicle
...i may get a cavalier or somehting and just uninsure my inline so i can do some stuff to it..sigh..i gotta plan this out a little better...i just want quick and hassle free...but i dont think i'm gonna get that..especially when i get around to the fuel return line...could i maybe get a shop to add this and get them to clean the gas tank while their at it? they should be able to do that fairly quick...i hopeIf someone were to go with 3 x TBIs or throttle bodies and moding the manifold to do it, then mount them in sidedraft position. Less turns for airflow in manifold, no float bowls, TBI would not know the difference. Better yet mount where TBIs are same angle as port runners.
Has anybody thought about milling the log 1/2 off leaving the back to clamp a shop built plenum to. Someone used to make a 3 X 1V that clamp to the top of a modified log manifold for down drafts carbs. Same idea but by milling 1/2 the log you would be able to port head before install plenum.
Has anybody thought about milling the log 1/2 off leaving the back to clamp a shop built plenum to. Someone used to make a 3 X 1V that clamp to the top of a modified log manifold for down drafts carbs. Same idea but by milling 1/2 the log you would be able to port head before install plenum.
Nor Cal Mike,
Holley makes a retrofit single TBI for 2-bbl Jeep straight sixes. The part number is 501-12. I have looked into this for my '65 Mustang 200 six as well. Holley told me that the kit was for manual tranny cars. The TBI does not have an IAC, which is basically a controlled air bleed to allow auto tranny cars to idle. It might be possible to make it work on an auto tranny car, but Holley was not very hopeful.
For the rest of you guys reading this:
As for the triple 1-bbl TBI, there are two concepts one has to remember
1) You can put put a forest fire with a garden hose.
2) You don't want to get a drink of water from a fire hose!
The injectors size HAS to be matched with the HP of the engine. Now using Falcon Six HP estimator, a 200 ci engine running 5500 RPM and 100% VE would require about 317 SCFM and make about 183 HP. I found a formula for injector sizing which is the following:
lb/hr = (HP) (BSFC)/ (# of Injectors)
Where BSFC is Brake Specific Fuel Consumption and is in the 0.45 to 0.55 range for N/A cars.
When you crunch the numbers based on three injector, 183 HP and 0.45 BSFC the flow rating of the injector is 27 lbs/hr.
The Holley 501-12 is rated at 300 SCFM and has a 90 pph injector. So it looks like the Holley kit is 3 times the size of what you need. The question would be: "can the Holley control accurately enough in this range?"
Looks like you MIGHT be taking a drink from a Fire hose.
Holley makes a retrofit single TBI for 2-bbl Jeep straight sixes. The part number is 501-12. I have looked into this for my '65 Mustang 200 six as well. Holley told me that the kit was for manual tranny cars. The TBI does not have an IAC, which is basically a controlled air bleed to allow auto tranny cars to idle. It might be possible to make it work on an auto tranny car, but Holley was not very hopeful.
For the rest of you guys reading this:
As for the triple 1-bbl TBI, there are two concepts one has to remember
1) You can put put a forest fire with a garden hose.
2) You don't want to get a drink of water from a fire hose!
The injectors size HAS to be matched with the HP of the engine. Now using Falcon Six HP estimator, a 200 ci engine running 5500 RPM and 100% VE would require about 317 SCFM and make about 183 HP. I found a formula for injector sizing which is the following:
lb/hr = (HP) (BSFC)/ (# of Injectors)
Where BSFC is Brake Specific Fuel Consumption and is in the 0.45 to 0.55 range for N/A cars.
When you crunch the numbers based on three injector, 183 HP and 0.45 BSFC the flow rating of the injector is 27 lbs/hr.
The Holley 501-12 is rated at 300 SCFM and has a 90 pph injector. So it looks like the Holley kit is 3 times the size of what you need. The question would be: "can the Holley control accurately enough in this range?"
Looks like you MIGHT be taking a drink from a Fire hose.
When I calculate it for a single injector, at 80% duty cycle and a BSFC of .45, I find you need a single 105 lb/hr injector to sustain 185 hp. At 90% duty cycle it drops to about 87 lb/hr. The Holley would be just about right in that regard.
As far as the lack of an IAC, that is not really a huge deal. A carbed engine has no idle speed control either, but can be set to work fine under the added load of the tranmission when in gear. There are also add on air bleeds that will increase idle speed at cold start and under heavier loads, like when the AC is on.
Bolting on three throttle bodies may seem like too much fuel, but the injectors will only spray what you program them to do. That's the beauty of EFI; you decide where the fuel and airflow curves plot based on load and speed.
The real issue is that you add complexity to the system for not much added value beyond looks. A single 2bbl TBI would be just as effective, if not more, than three smaller units. No messy throttle linkage, no odd plumbing.
Unfortunately, I don't think a single Tempo TBI flows enough fuel, but it is rated at a low 35psi, I think. It is probably rated to sustain about 100hp or so. Cranking the fuel pressure up to 50 psi might make it flow enough for 125hp. One of the neat things about the Tempo TBI is that the FPR is on the housing and can be adjusted with an allen key.
T5;…0AAnd there's really no reason you couldn't mount the Tempo unit as a sidedraft. After all, there are no float bowls and nothing to leak out when the engine is not running.
As far as the lack of an IAC, that is not really a huge deal. A carbed engine has no idle speed control either, but can be set to work fine under the added load of the tranmission when in gear. There are also add on air bleeds that will increase idle speed at cold start and under heavier loads, like when the AC is on.
Bolting on three throttle bodies may seem like too much fuel, but the injectors will only spray what you program them to do. That's the beauty of EFI; you decide where the fuel and airflow curves plot based on load and speed.
The real issue is that you add complexity to the system for not much added value beyond looks. A single 2bbl TBI would be just as effective, if not more, than three smaller units. No messy throttle linkage, no odd plumbing.
Unfortunately, I don't think a single Tempo TBI flows enough fuel, but it is rated at a low 35psi, I think. It is probably rated to sustain about 100hp or so. Cranking the fuel pressure up to 50 psi might make it flow enough for 125hp. One of the neat things about the Tempo TBI is that the FPR is on the housing and can be adjusted with an allen key.
T5;…0AAnd there's really no reason you couldn't mount the Tempo unit as a sidedraft. After all, there are no float bowls and nothing to leak out when the engine is not running.
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Anonymous
Guest
thanks mustang six...thats more the info i was looking for....stock, the 250 only gives about 100 hp anyways...and with only a few minor mods, eg. exhaust...that should be great...i think once i get my new job (fingers crossed...did an interview and the boss is on vacation now, so wont know for sure till weekend) then i could start purchasing a few things with every check....and then when i have it all, there will be winter to worry about :x
