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Carb or EFI?
https://slantsix.org/forum/viewtopic.php?t=16840		 Page 1 of 1
Author:  herbhill [ Sat Apr 01, 2006 8:43 pm ]
Post subject:  Carb or EFI?
Well I did the switch to HEI setup, engine runs alot better. With HEI it actually started to clean the carbon off the tips of the sparkplugs I put in a couple of months ago. Now the next project; I started to collect the used parts for the article on EFI setup. Would it be better to do the EFI setup or go with the weber 32/36 carb setup? I had seen the post on the weber setup and it looks pretty sharp on a /6.
Author:  mrhite65 [ Sun Apr 02, 2006 10:19 am ]
Post subject: 
I would think the Holley/Webber would be easier, but the EFI would be more efficient.
Author:  Reed [ Sun Apr 02, 2006 11:02 am ]
Post subject: 
I think the hardest part about fuel injection, especially since you have already converted to HEI would be fabricating the fuel rail and drilling and tapping the intake manifold for injectors. Doctor Dodge has a great tech article about tapping the manifold in the articles section, but there isn't a good fuel rail article yet.

My plan for my van (someday) is to convert it to GM batch fired fuel injection off of a mid 80s 3.8 liter GM car. The injection is triggered off of the HEI ignition (which is the whole reason why i started messing with HEI in the first place) so all you have to do to convert is run HEI and get all the fuel injection sensors and components installed on the engine. It really would be a straightforward swap.

Webers would look cooler, and be a simpler installation, but Webers are more complex to tune than a Holley.

If I were in your situation I would just go the EFI route.
Author:  Lars [ Sun Apr 02, 2006 12:00 pm ]
Post subject: 
I would go the EFI route also if possible. I've had EFI cars, and (obviously) carbed cars. I found it much easier to tune the EFI as opposed to tuning a carb. I eventually want to put EFI on my 73, 74, and my 84 Ram.
Author:  Matt Cramer [ Sun Apr 02, 2006 12:48 pm ]
Post subject: 
That would depend on your skill, budget, and future plans. Carbs have the advantage of a low budget and less work required, and work well for naturally aspirated buildups.

A port fuel injection system is rather expensive. Clifford had a set of port EFI manifolds and fuel rails for sale for a while, which would bring down the cost if you can still get them. Otherwise this can cost a small fortune unless you are an expert machinist.

A TBI system is a bit more affordable and requires less fabrication. It may be a good compromise if you want EFI's tunability without the expense of a multiport system.
Author:  kesteb [ Sun Apr 02, 2006 1:43 pm ]
Post subject: 
The SDS site has wonderfull DIY articules on installing EFI. It includes building manifolds, building fuel rails, how to choose the correct injectors, etc.

http://www.sdsefi.com/
Author:  herbhill [ Sun Apr 02, 2006 2:56 pm ]
Post subject:  Thanks for the info.
I am fairly good with a wrench but will probaly have a machine shop do my intake for the injectors. because I cannot drill a straight hole if my life depended on it. I wanted to go with the EFI but just was not sure which would be more efficient.
Author:  Lars [ Sun Apr 02, 2006 5:44 pm ]
Post subject:  Re: Thanks for the info.
Quote:
I cannot drill a straight hole if my life depended on it.
Hey! I'm a member of that club too! :lol:
Author:  Pierre [ Sun Apr 02, 2006 10:28 pm ]
Post subject: 
I have mpfi on my slant now - mpfi all the way is my vote.

I bought my clifford manifold already drilled out for mpfi, from clifford, for same price as their regular manifold. Fuel rail also came from them for a whooping $20 more. I've gotten estimates in the ~200 range, to modify an existing manifold for mpfi, including fuel rail and hold downs.

What this translates to - skip over tbi and go directly to mpfi. Cost difference, relative to the entire project, isn't that much, especially if you get junkyard injectors and clean them yourself.

And about the GM setup - if you do decide to go with GM, or any factory computer for that matter, make sure its hackable to the point that you can tweak it as you wish (the GM 1227747 has a good aftermarket following interms of tuning tools). Thing is, between buying programmers and chips and going through that hassle, the cost of a megasquirt is more then coverd. One major point of having efi over a carb is tuneability. So getting stuck with a factory calibration, even if its for a similar sized engine, is one step in the wrong direction imo.

One thing I will say about efi - do it right the first time, don't take any shortcuts or they will come back to bite you. Ask plenty of questions if you have any doubt!
Author:  herbhill [ Sun Apr 02, 2006 11:05 pm ]
Post subject: 
Will take it slowly and try to do it right. I have been reading posts and bought a book on GM fuel injection trying to learn as much as I could. I use to think that fuel injection was too compilcated, but after reading the book I have been afraid of working on them for no reason. The only reason I thought about the weber carb was to hurry up and get rid of the 1bbl carb. It seems to me that mopar wasted a good engine by tieing one arm behind its back.
Author:  Pierre [ Sun Apr 02, 2006 11:25 pm ]
Post subject: 
Modern efi (obd II and onward) can get quite hairy really fast. Those harnesses are massive, need an entire book dedicated to wiring alone.

Check out www.megasquirt.info and www.msefi.com for more on the megasquirt system.

If you seriously see efi in your future, save up your money and energy, shelf the weber idea.
Author:  herbhill [ Sun Apr 02, 2006 11:42 pm ]
Post subject: 
After reading some of the comments I plan to go with the EFI. It's just going to take a little while to get everything together.
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