quote:
Originally posted by Joules:
Mike,
I feel for you every time I read this thread, please don't let this setback mar you Pantera ownership experience.
There's a lot of talk about Webers, but you have an 8 stack EFI system, which is infinitely more tuneable than Webers IMO. Haltech is also a great brand and the older versions are relatively easy to tune. There are also a number of Pantera owners who know their way around tuning it. You can download all the software and manuals you need from Haltech's website and may just need a laptop running the older Windoze 98/2000. Floppy disks can be transferred to a USB or like pretty cheaply, but you may not even need it.
The difference in the plugs is likely down to synchronzation of the butterflies and a good synchrometer will help.
One alternative to really enjoy the car for now is to get yourself a Holley 4 barrel and switch out until you have time/money to address the EFI challenges.
Good luck and please stay with it, you will be rewarded eventually.
Julian
EFI and Weber 48IDA carbs on individual runner intake manifolds react EXACTLY the same at idle.
Air filters are restrictive and effect the air/fuel ratios.
Torque can be tuned by changing the length and diameters of the velocity stacks.
Since air filters are restrictive there is free horsepower and torque to be gained AT ALL RPM by running without them.
A/F ratios to the cylinder are artificially enriched by running through an air filter.
It should be noted that even screens have this effect but to a lesser degree.
What fuel injection is doing is LIMITING but not totally eliminating blow back through the carbs, i.e., fuel reversion. 2) allowing the CPU to vary the a/f ratio according to the program that YOU write into it, i.e., read off of a script, that tells the computer to maintain a particular a/f ratio under particular operating conditions.
With ONE oxygen sensor it will read the average a/f at the location of that sensor.
In order to tailor that to each individual cylinder, you need a sensor for each cylinder located within a certain distance from the exhaust valve.
That is the advantage of a "digital" device.
Weber carbs react exactly the same as EFI on individual runners except they are subject to reversion, because they maintain emulsified fuel held in suspension in the venturi.
That mixture is pushed back out of the carb since it has no where else to go. This is created by the power pulse of the camshaft overlap.
You need to reduce that overlap on a Cleveland to about 26 to 28 degrees to make the reversion a non-entity.
The carbs of course can not vary their jetting and a/f ratio while running like EFI CAN. Therefore it is simply an analog system.
The similarities are that even though an EFI system controlled by a central CPU PROMISES to vary the a/f ratio to perfect stoichiometric at idle, the engine does not have that capability of idling on it with an IR manifold. It can only do that with a common plenum manifold.
You see with your car what the CPU is capable of at idle. The fact is that it is going to be heavy at idle JUST LIKE the Webers are. I doubt that it is giving you 14.7:1? Sounds like closer to 13:1 at idle? It probably needs to do that to keep the engine running at idle?
The difference between the carbs and the EFI at start up and idle, is that with EFI you don't have to pump the gas to start a cold car and you do not have to tailor the accelerator pumps like on the carbs.
Does the EFI make more power over 3,000 rpm? Not really. Does it make more power under 3,000? No. It just cost more to set it up so that the arm chair engineers can fool themselves into thinking that they don't have to get their hands dirty and they can fix it with a few strokes of the keyboard, more importantly, and THAT THEY THINK THAT ACTUALLY MAKES THEM KNOW SOMETHING!
To each his own. "One" still needs to sweat a little and know how to work the system. You (you in general, not you specifically) can't be a theoretical physicist. You have to take off the Gucci loafers, know how to at least turn a screw driver and get more than a little dirty.
Having said that, these systems take MUCH more than a little patience and take MUCH longer on the learning curve to understand them. Doesn't matter EFI or Webers. Both are a major PITA. Very similar characteristics. Very Similar results. You can't sit down for weeks from working with them.
Me tacky? Maybe? I leave the Grey Poupon home with James the Butler. He never liked me anyway? I don't have Gucchi's either. I got a deal from this guy on the street for Googee's. They look just like them and they were cheap!
