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> Jensen Healey & Jensen GT Tech > Engine & Transmission > Dellorto/Weber upgrade is a carburetorism

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OverdriveGear
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Here is an interesting website about customizing an ECU for any car (and obviously this post is in respect to JH).  http://www.megasquirt.info/  This company offers you boards and processors to basicly make electronic fuel injection (among other things) from the ground up.  It's really quite ingenious.  I go to the Georgia Institute of Technology (Ramblin Wreck type) and the SAE racing club uses this system on their BMW 325e race car and it is absolutely amazing.  Take a look at this site and see what you all think.  The weber/dellorto manifold is designed to accept port fuel injectors.  Once you had the board, processor, and software to tune it; all you need from there is the easy stuff:  the mechanical.  This would be a throttle body w/ MAP sensor, fuel injectors, rail, and camshaft position sensor.
I suppose the most difficult parts of the system would be to fashion an airbox and figure out a way to put on a honda/mitsubishi/toyota cam position sensor.
If you aren't afraid of some computer science (code written in C) and mechanical engineering, this would be really nice.  It sure beats the hell out of ANY carburetors and throttle body injection (which isnt a whole lot better).

Jensen Healey
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Let's not start insulting carburetors. Some of us here like old cars and the parts that came with them. When you finish your project you can compare your dyno plots to Yellow Dog's and do some bench racing. http://jhppg.com/gallery/album62

I have seen the Megasquirt website. Pretty cool stuff. You'll have a great time building the system. Certainly modern technology "beats the hell" out of 30 year old carburetors and a Honda Civic went 195 mph at Bonneville but I wouldn't trade my Jensen or the Dellortos.

I think Jensini dyno'd at 240 hp with port on port injection and Elgin cams.

We're all having fun!

Greg Fletcher
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What, computer boards on our beloved Jensens? Heresy I say! I actually prefer to tinker with my mechanical JH to get away from all the computer crap and endless problems I have to deal with all week long. That's no therapy, leave the Frankenstein stuff for the Hondas- there are endless candidates other than a JH available for that.

Jensen Healey
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That's my take on it but to each his own. As long as your having fun it's the right thing to do. Perhaps some others on the board with the electronics bug would like to continue this thread.

I just want a supercharger. He He

Kurt

(What ever happened to the JH Camper Abortion?)

Jim Sohl
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Without endorsing either camp, I view 'dell's and all other carbureted engines as a chemically powered, very high gain, analogue amplifier.  A very tiny torque at the throttle shaft becomes a very large torque at the rotating, crankshaft.  As with any hi-gain amplifier, a very small non-linearity when 'processing' the input signal can give rise to a much larger, unwanted result.  'Same for noise.  Given that what 'dell's and most other carburetors do, try to control thousands of psi above a piston using a tiny vacuum signal, it is to be expected that the interactions between the various 'circuits' within the carburetor will at times be counter-intuitive.  In reality, what is happening is that the effect of an alteration to one circuit might be quite small or of a stand-alone nature, while an alteration to another circuit might be quite large or highly interactive with other circuits.  Which is which?  Obviously, if I knew, I would write about it.  It is just interesting to consider that tiny changes in any of the several vacuum circuits can lead to steep, exciting response curves, or, popping, coughing, and you know the rest.  It seems then natural that the passing of air through internally curved tubes creates 'signals.' Have fun, just my one cent's worth.
Jim


OverdriveGear
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Make no mistake about it, performance carburetors get the job done sure enough.  That's quite apparent in Yellow Dog's numbers.
I'm looking at this from an efficiency point of view.  If you can deliver similar power, lower emissions and lower consumption why not do it?
I understand the argument that Greg puts on the table and I can assure you, nobody likes to deal with malfunctioning electronics.  But then again, carburetors have the same type of issues:  Stuck floats, clogged jets, rebuilds, etc.  Over a century-old technology!  The system is way to dependent on the environment and karma in my opinion.
It's just a matter of what you like to tinker with, just as Greg put it.
I'm obsessed with efficency, new designs, and technology; I guess this is a good thing for ya'll in light of the fact that I will be designing your new cars in a couple years.  I will go the electronic route.
Happy tinkering!

upstate mike
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Hi, if your seriously looking at fi check out http://www.twminduction.com/Home/Home-FR.html

I've been looking at this for awhile and figure it to cost about the same as 45 mm dellortos. I've been working more and more with fi and I've come to like it .

                                                        Mike K

pc
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Keep us informed as you go!  Sounds like fun.
 
I can never get the thought of doing an EFI out of my head, no matter how hard I try.  So far I’ve managed to keep it on the way back burner but it could rear its ugly head at any moment.
 
I originally looked at stuff like TWM’s throttle bodies but seeing the factory Esprit EFI manifold was an epiphany.  I’m sure you can find them used for a whole lot less than new throttle bodies, they have nice long individual runs for better low/mid torque, they already have port injector bosses built in so there’s no messing with modifying a carb manifold and they have a single throttle body inlet – no synchronizing (you can do this with Del or Strom manifolds too if you build an inlet plenum).
 
Next question; is the electrical system up to running a high pressure fuel pump plus injectors plus everything else at idle with the lights on?  If not, there’s another project.  And while we’re at it might as well throw in a multidimensional mapped crank triggered ignition and…..
 
 
PC.

edward_davis
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I for one would like to hear about an EFI conversion for the JH.  I love carburetors, but as time passes there are more tools for fixing EFI than for carbs.  Not sure if I would ever change my JH to EFI, but if I ever do a project with some vintage Detroit steel, I would probably go the EFI route.  Then again, there's something elegant about a four-barrel carb....

Definitely interested to see how it goes, though.



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