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Looking at going back to a carb!!
Hi All-
So, not to beat a dead horse, on the EFI vs CARB debate, but, if you have a carb, how bad does it actually stink of gas. Running or just in the garage?? Original thought was to put on EFI and go - such has not been the case!! I have a PJIII EFI on my 427W Ford Racing Crate Engine and I've had a lot of problems 'dialing her in' or even getting her to idle well....can get close but not right on...!! It started out with a defective TPS - that I think blew the ECM and now my O2 sensor appears to be fouled...I'm fed up! I'm thinking I may want to go back to a carb for simplicity sake. No O2 sensor, TPS, ECM, AIR mix control to eventually go defunct...no electrical connections to corrode or disconnect!! And I won't have to spend all my free time trying to figure out all the tables and programming!! Besides, I think I'd be able to tune a carb just as well...at least for my driving. Only question is some calculations say 600cfm (street) and others say 750cfm (race)! Anybody done either one or both?? I'll drive maybe 5000 miles a year MAX!! At 535hp and 545 torque I don't know that I'll need the extra 150cfm - unless they would basically run the same except at WOT!! Suggestions..... Thanks, Gary |
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Good luck getting 535 hp out of 600 CFM... Just sayin
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A properly set up carb has no more smell than EFI. The 750 is fine for a 427. Other than cold starts, I see little benefit to EFI on these cars, unless you're concerned with fuel mileage or emissions. Have the carb set up by someone who knows what they are doing, preferably on a dyno. Worth the money spent.
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Save it Chas. :LOL: |
I don't get any gasoline smell from mine.
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Mine smells fine. I would be more around 800 CFM.
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why not take it to a professional and have a custom dyno tune?
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Mine stank. Garage stank, my clothes stank, nature of beast
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"I love the smell of napalm in the morning".
It smells. I love it. The Wife doesn't. <-- even better. (shhh) |
Is there a hp limit on that system?
I've been playing with the idea of going efi (currently have quick fuel 780), it would be nice to lose a bit of the gas smell on my clothes and get a little better mpg (though I'm sure that even with efi these cars exhaust will still leave a bit of an odor). |
You can buy an additive that makes your gas smell anyway you want, grape, strawberry, cherry, etc...
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A couple of things: 1) you may actually be closer than ever to dialling it in. Changing the O2 sensor may "reset" the baseline reading and set you on your way, thats not exactly a difficult task. 2) the rule of thumb is the smaller the carb the better the throttle response at street rpm levels, but the sacrifice is the less air it can gulp down at upper rpm levels. Hence a small carb will limit your hp sooner, but why it's also recommend for the street. The challenge is to find the balance. |
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Once was convinced to go from 750 dbl pmp to 850 dbl pmp on a Chev 454 honestly had my doubts.Wow! what a wake up call that was.Just saying.The best thing about a carb is the tunability ease,small amount of money needed to experiment. I too tried converting to EFI and had the same problems with failed parts biggest problem was the car was a daily driver and waiting for replacement parts was more than we could endure.Besides will always love the carb idle! |
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Steven and Loosy at Full Throttle in Reno, must have done it right. |
When you replace the efi install a wideband sensor, will help considerably in tuning the carb. Get something adjustable so you can diddle with it. If tuned right, there should be no more considerable smell than efi. Lot of the carbs come set up rich so there can be a lot of exhaust fumes, which like to hang on to your person. I haven't noticed too much after I made adjustments to the cruising afr and everything else. Like the efi though, it is a learning experience, don't expect to tune it via the internet, that helps in the info collection, but it is eventually up to you.
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600 will be to small.......800 about right...750 will work...........the spreadbore....( I know..:)......has small primaries for the throttle response at low speeds....which is where we live.. Once warmed ..no smell..
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^^ This is your correct fix. You are clearly unfamiliar with how to tune an EFI system so go to the professionals and stop wasting time and money. The EFI will outperform a carb in every aspect you can measure. On the other hand if you want a carb, for what ever reason, go buy one and put it on like we all have done for decades. Smaller ones perform better at low engine speeds and bigger ones perform better at high engine speeds. Use a wideband, as has already been suggested, and dial it in. You will surrender some drivability, mileage and cold start manners but it will work just fine - like they always have. Sell your EFI to someone who wants and knows how to use one and repurpose the dollars for something else on the car. Ed |
EFI to Carb Conversion Cost
Jerking the intake off and plopping a intake and carb on is easy, but what about ignition, fuel delivery, and wiring harness?
Assuming you have a decent EFI system, it should be controlling the ignition timing and fuel pump, too. Perhaps the fan and speedometer, as well. The EFI fuel pump is putting out way too much pressure for a Carb, so that has to be changed. If it is a return type fuel system, you should remove that. Odds are you are going to have to buy a distributor. When you remove the EFI wiring harness, you need to provide for just about everything that it connects to other than the fuel injectors, and sensors. Then you are going to need to tune the carb and get the timing curve set up for your engine. As stated to do it right, you need to use a wide band O2. Many don't and put up with the stench and leave 50 Hp on the table. Without the dyno you will leave more Hp on the table do to the timing curve not being dialed in. Not hard to drop a grand on intake, carb, distributor, fuel pump, etc. Then another $500 to get it tuned. Or Take the EFI to a good tuner. He more than likely can fix it and tune it right for under a grand. |
I would keep the efi if you could......maybe someone on here has the input information that you need
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