Appreciate everyones comments and as ever interesting to see a range of views. In my situation I have a good spec motor in my cobra that I have never really been able to enjoy, partly because just starting the car after a period of layoff can take 15 mins or more to get to a steady idlde once she actually fires. I have experienced a few really good sessions in the car when it has performed really well only to be disappointed on the next drive out.

I dint race my car and dont have big changes in alttitude or tempaerature - I live in Scotland and to get the car so that if i fancy a drive I can just jump in start her up and drive would eb a huge bonus.

I obviously want to get the best I can from the pretty good motor that I have and am not minded to be changing components on a regular basis but dont want to be dependant on the local dyno if the car requires frequent recalibration/setup.

I have been quoted the price stated from a reputable shop experienced with workong on Cobras and race cars and they have put together a custom setup using various components (MPFI) that they are confident will give me the best I can get from my motor. The problem I have is the price.....so....if TBI, either Sniper or Exterminator can get me most of the things that are importnat to me for less than half the price that's probably the way I'm going to go.

Also interesting to a number of reputable crate motor suppliers in the States now proving motors with Sniper EFI so cant be that bad can they???

Again thanks for all the input guys.....still looking for an answer as to Sniper versus Terminator......

I would like to add something no one has mentioned , cool factor. multi port looks way cooler!

Silly??? No.

Ignorant? Well, I don't profess to know everything, but this I do know.

Simplistic? There, you've got it. Absolutely.

Even a primitive hammer and chisel can be used by a skilled artisan to produce masterpieces in stone.

Bob, you are an artisan. But that puts you in the top 10%.

Ed's and my comments are directed at the 90% that this simple EFI is going to solve a problem they have struggled with, only to find that in most cases they spent a lot of money and still have the same problem.

The "FAST" and other systems seem to be reasonably robust. Their self-learning systems will get you going, but are only a start. I know one person that is happy with it, another that ended up spending the money on the dyno tune.

The Rosuh 427IR started with an Accel DFI system that could run either mode but was configured for MAF but didn't actually operate above 5000' due to an incomplete configuration of the altitude adjustment table coupled with a lack of understanding of fuel/air flow through the faux 8-stack trumpets. Fixing this had the benefit of me learning alot about fuel injection systems that I will never use again (see earlier discussions about kits and learning skills that you'll only use once, but I wasn't going to let a computer get the better of me). Roush has since changed to one of the FAST-like systems (don't know which one).

What you describe with your laptop adjusting for different conditions is an electronic re-jet. But where did those tunes come from??? Maybe you actually spent the time in the different conditions to arrive at them. Great. Maybe those "tunes" are "open source" and can be downloaded from the internet. Great. But it's still a manual intervention, and admittedly less intervention than a physical re-jet. The whole point of this discussion is about using speed-density vs. a MAF system. If your conditions are static, then the single solution will work. If you go through changes the MAF system will take care of those adjustments automatically.

To the OP: I think you're getting the gist of the pros and cons. It's your car and your money. Personally, I'd just get the carbs set up properly. The problem you describe seems fairly basic. Of course the problem even here in the US is finding a mechanic that can even identify a carb let alone know how to really "manage" one (you said you're in Scotland, right). For that reason alone the EFI system might be your best solution.

Good luck!

Keith (I am guessing from your screen name),

The blind from birth conundrum and the Knight's Templar admonition are unvarnished but just the way it really is.

The number of EFI users who have used more than one fueling model (i.e. Alpha-N, Speed Density or MAF style) can typically be counted on one hand with a lot of fingers missing. The problem is quite similar to the blind from birth conundrum. Most users will be enamored with how well the engine starts compared to carb(s) and loose sight of the tuning for drivability or MBT (maximum brake torque) timing or sometimes even max power.

When you ask the "satisfied user" a simple question about the enrichment strategy they used for accelerator pump replication, you will get a blank stare. When you ask them if they used a time based model, a wall wetting AE model or an EAE model, a wall wetting x-tau model or why they used one over the other, you will get a blank stare once again!

So lets go to another consideration. Ask them if the injectors were flowed to the SAE J-1382 standard — blank stare time again. It’s a dirty little secret in the industry that not all fuel injectors of the same part number actually perform the same. Sooo, who flowed the injectors, what were the conditions they were flowers under, were they corrected values or raw data, did they get high and low slope values for the injectors, what is the actual flow rate of the injectors, and of course lets not forget their short pulse behavior.

Aside from the blank stares you will get comments like why does that matter (to me) and I am sure the manufacturer addressed that for me along with the "I never heard of that before," commentary telling you quickly how valuable that opinion is.

There is a short way home for you that involves keeping the carb and either learning how to tune it (more time consuming) or buying someone who does (more risky). Alternatively you could get the MS3Pro hardware I described in post #3 which addresses all of these issues and a boasts a lot more (not meaning to terrorize you) allowing you to do a spectacular tune. BTW The MS3Pro lets you choose Speed Density or MAF fueling models, blending Alpha-N where it is better suited than the other two.

Spend $199 and buy Greg Banish's Advanced EFI Tuning Series DVD's <= clickable. the DVDs have six hours of training, half on prepping the car and half on tuning fuel, timing, air flow and other maps in the ECU. Learn not only what it is about but how to do it right! More importantly learn it from the guy Ford, GM and Chrysler go to when they are in a jamb.

Go buy the MS3Pro ECU and associated gizmo's from DIY Auto tune. Do it yourself and know not only that it is done correctly but how to do it correctly.

BTW, nowhere in any of these posts have I commented on the fail safes the aftermarket ECU brings to the table to protect your engine or in the case of traction control you and your car, or in the case of power adders like nitrous, turbos or blowers the tools to do the job correctly — and I've just scratched the surface.

Tony and I are trying to help you avoid stepping on an engine fueling land mine hidden below ground level that is for all intents and purposes invisible. You are currently struggling with a carburetor that is mis-behaving. Tuning a carburetor has fewer tunable variables and is less complex than tuning an EFI system.

Tony's representation of a speed density system as an electronic carburetor is spot on. He did not represent it as inexpensive or anything other than an electronic carburetor. It gives you a digital adjustment capability for what effectively were accelerator pump(s), jets, power valves and air bleeds. It also gives you digital precision and adjustability. Most importantly it does not give you any way to measure the air mass being consumed by the engine which is foundational to the tuning process. Remember AFR is pounds of air divided by pounds of fuel.

Virtually all the speed density systems will provide some level of self learning (read tuning) capability adequate to minimally get the car drivable if not better. That's the condition you need to drive to the dyno shop and get the tune properly done. Once you have the car properly tuned it will perform admirably for the ambient air conditions at the time of tuning.

The further you get from those conditions the further out of whack your tune will become. Ambient air related changes will only affect a speed density system, they will not affect a MAF based system — it's really that simple. It doesn't mean speed density does not work, it does! However, when atmospheric conditions change so to will the quality of your tune. This is not be the case with a MAF based system.

You are essentially out on the fringes of the Cobra universe effectively by yourself. That means you will either need to learn how to manage the tune for your engine or you will need to travel and pay money to someone else, who you hope will be able to help you. This should sound like the pickle you are currently in and stymied by with your carburetor.

Whether you ultimately embrace a carb solution or an EFI solution you are going to need to send yourself to school and learn how to manage your engine's fuel delivery system. If you elect to do this with an EFI system I highly encourage you to use a MAF based system and spend the money to learn how to use it — you will be muuuuuch happier in the end.


Choose wisely ...



Ed

Ed, clearly you know your EFI stuff - I'll give you that.

Regardless, your dissertation on the various elements of an optimal EFI system remind me of the numerous conversations and meetings when I worked in IT services for many years. Hearing those with deep technical knowledge (a.k.a. geeks) is often enlightening to those so inclined, but the vast majority of people, whether IT users or Cobra owners / drivers, are interested only in what matters to them. Does it work? Is it reliable? Can I count on it to meet my needs?

While perhaps not 'optimum' or 'the ultimate solution', TBI meets the needs of a significant number of users, er, Cobra owners and drivers. They're oblivious as to whether there's a 'better solution' - and that's probably okay. IMO, TBI meets the KISS principle - Keep It Simple, Stupid. Another way of expressing it: How good is good enough? TBI is 'good enough' for most of us.

Like those tired of hearing IT geeks blathering on and on about the merits of the optimum or ultimate technical solutions, I'm not interesting in seeing any more of your MPFI dissertations.

Thanks.

Have a safe and Merry Christmas.

:LOL::LOL::LOL: Alright! Nothing like a little Holiday cheeer.:3DSMILE:

Well said. It gets old listening to people blather on about stuff that doesn't matter to 90% of the car population. It becomes ridiculous. Does it work? Yes. Does it work a LOT better than a carb? Yes. Does it work as good as MPFi (batch fire or true SPFI)? Yes. Ok. End of subject. Telling somebody to spend $5000 over $1500 becomes stupid when they don't even know how the vehicle is used.

While I understand and appreciate the preference you guys have for simplicity, you should also notice the post was not to you, it starts out directly addressing the OP (whom I think is named Keith) who solicited the information.

You are not being forced to read the post. In fact the decision and the election to read was your own. If you prefer not to do what you decided and elected to do (I admit that is a bit confusing but then again I am not the one who is doing it) then I encourage you not to. After all, amid all the misdirection, I think that is what you indicated as your preference. If you choose to read the post then you and no one else, single handedly now own both the responsibility and the frustration.



Ed

You know we're a bunch of ol' farts when somebody is bit_chin' at someone else because they answered the question too thoroughly. :LOL:

eschaider,
I appreciate your advice and insight, although more information than I require. The OP would probably be well served with one of the highly rated TBI units. Some would say, I'm a little OCD, when I'm researching a project, I welcome as much information as I can get and as easily as I can get it. To much is never a problem when it comes to free advice! Correct me if I'm wrong, we're all here for our common interest and to offer/request advise with regard to our cars. Let's not let egos or anything else keep someone from providing free advise, no one is obligated to abide by any advice offered here. If however, something is factually inaccurate and needs to be addressed, not a difference of opinion, please feel free to enlighten us. Now I'm not a moderator, so what I say is just opinion. Wishing all a happy safe holiday and a prosperous new year.

I have no disagreements with your position or rationale. I believe everything I have posted was factual and without the presence of ego, wounded or otherwise.

Like walking up to a news stand we tend to purchase and read what we are interested in and not purchase what we are not. Internet forums like Club Cobra are no different. If there are threads you are interested in you read and perhaps participate. If there are threads you are not then you do not. If the level of tech is more than you are comfortable with then it becomes a thread or post you simply skip. The reader has complete control, no one forces him to do anything.

If a reader confronts a poster for tech he does not like or perhaps understand there is a reasonable question as to why. The obvious solution is to not frequent threads where the tech is more than you are comfortable with. If you choose to support a position that is not logically defensible, the person who is on the thin ice is the promoter of the position that is not defensible, not the person who factually demonstrates the logical flaws.

In the end it is very much like the news stand. Don't like the magazine? Then don't pick it up and start reading. If you choose to participate and present logic or reasoning and get called on it (which I did not do to any one individual) your should be prepared to defend your position fairly, non-confrontationally and factually.

When you get caught with your hand in the proverbial logical or factual cookie jar and respond with unsupportable commentary or personal attacks it does nothing to further the purpose of the forum, which is to inform and provide a source of knowledge on various Cobra specific subjects. Personal attacks are the refuge of the uninformed and do nothing to further learning.



Ed

Ehhh, I don't mind being the target of uninformed personal attacks. And I actually enjoy being the target of personal attacks from the misinformed. It's kind of like sparring with someone three weight classes below you.:LOL:

I know, Patrick but I am trying to be polite :LOL:


Ed

On one hand you criticize the info of the tradeoffs of one EFI system vs the other based on price, yet you don't suggest that the OP simply spend $300 to get his carbs adjusted properly instead of ditching it for a 1500 EFI system that will result in the same operation (given his conditions)???

The question was on the various types of EFI systems. Objection your honor, asked and answered.

I have read all the comments at least three times, and all I can say is, maybe Tasca was onto something when they built the engine for CSX2006, with a 2bbl carb! Never heard Herbie Hancock complain about lack of power when he beat Miles Davis and his Ferrari, or went over several mountain passes on his way to California. Maybe that's why he is the longest original Cobra owner in the world. Then again, the Cobra is named Watermelon Man after the song that allowed Herbie to buy the car, and it's a pretty smooth song, just like the car! Cheers, Dennis

I had carbs on both cars initially. Now they each have multi port EFI from Holley - the HP model. Considering they were tuned by a rank amateur (me!) they run fine.

I would have kept the carbs except for one thing: the substance we laughingly call gasoline.

When the Cobras were new in the sixties, gasoline was quite different from what we have now. The current boiling point of alcohol-laced gasoline is hardly over 100 degrees F. After a nice run in either car I could watch the Holley carb bowl vents emulate Old Faithful as the lower temp fractions boiled away, flooding the engine.

EFI has a 44 psi fuel pressure that keeps the boiling from happening.

So good luck with the carbs...

Tom

PS: the no-alcohol gasoline may help with a carb - never tried it, as it wasn't available when I had to switch.

This is also a fire hazard with depressing after effects.


Ed

First I just wish to say, I do not disagree with anyone's comments . I found in practice you use expensive,calibrated testing equipment, but the censors are not always accurate that are controlling your injection system.remember manufacturers are trying to keep cost down.All that said carburetors have been around a long time and a lot of time has been spent trying to perfect them. Check out the electron carb or the smart carb just realize there is more than one way try and keep an open mind. Also I realize the carbs mentioned are for motorcycles but I was just trying to open some minds It not me just talking.

I am more then old enough to remember Ethyl gas, Tetraethyl. Man did that smell good! Little did we know that at the New Jersey Dupont Deep Water plant, the building where Ethyl was made, had the nick name, The House Of Butterfly's, because the men would try to brush off, and chase imaginary bugs, and sometimes, chase them out second story windows. At least 16 workers went violently insane, and died in strait jackets. Then again, I can remember being in the pits at the inaugural Denver Air Race when the fuel truck for the unlimited racers came out with the 180 octane fuel. There was a warning on each side of the tank simply stating, Fatal If Inhaled!

I grew up on a farm in South Dakota. After a day with grease and dirt up to our elbows and beyond we'd go to the gas tank and wash the grease off with the leaded gas. It evaporated in seconds.