Carburation or Injection (that is the question)

[Roscobbc]

With the seemingly increasing popularity of TBI carburettor 'replacements' like FiTech or Holley Sniper and others I'm surprised none of us seems to have taken-up on what in theory should help our cars to operate better. With some of the higher specification replacement carbs in excess of £600 - £700 the additional cost of a throttle body fuel injection unit at £1200 - £1600 isn't a great leap forward in cost, especially if we can see economy and running benefits for our carb'd vehicles. OK so you have to add the cost of a high pressure fuel pump. fuel lines and having someone weld a bung on the exhaust for the CO sensor. These systems are 'self learning' and if one reads the American forums the days of difficult starting in winter and the difficulties of getting the automatic choke adjusted will be thing of the post. TBI is still updated 1980's technology though. For an additional £500 - £600 or greater a similar gets you a self learning multi port injection system like Edelbrocks's Pro Flo 4 system c/w new inlet manifold and tablet enabling you to to set-up and use as a 'dashboard' is now available in the UK - has anyone ever considered either system?

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https://www.rodauthority.com/image/2019/07/edelbrocks-pro-flo-4-efi-with-tablet-makes-engine-tuning-a-breeze-2019-07-12_20-17-49_041141-1440x670.jpg

 

[Knodty]

Hi Ross,
Been thinking of FI for a couple of years now but will have to wait for my move to Norfolk and a bigger garage space to do it. I think I’ll go with one of the Edelbrock’s systems tbh as I have used a lot of their products in the past with great improvements. Have heard of a few issues with holleys system, so I think it’s a no to that one. still need to do a bit more research into it all I think before I take the plunge. Over the last 27 years I have a number of different carbs, a Holley which come with my car when I bought it, (not original carb), then fitted the Edelbrock’s 750 CFM performer series carb to a new Torker 2 manifold, then some 10 years later fitted Edelbrock’s performer RPM Manifold and a Holley 830cfm DP race carb. All of these had certain issues like sticking needle valves, tuning issues, accelerator pump insufficient delivery, sticking/inoperative seals etc. I’m hoping that the FI will eliminate the need for tuning, hopefully, then all you have left to worry about is sticking injectors, sensor problems etc.
I think that most of my problems are heat related now with the Twin Spal Fans, and having a black car doesn’t help with heat disappation either, only time will tell.

 

[Dazaa]

I've just done a sniper install. Not as simple as it seems, have to drop the tank, fit a new pump and return line, 02 sensor ect. Fires up instantly like a brand new car every time, haven't driven on the road yet but considering all the headache I had getting it to start before the efi i'd never go back.

 

[Roscobbc]

Thanks for comment Dazza - come to any conclusions about your misfiring issues yet? - even though you've just said that the Sniper fires right-up every time given that you have this misfiring issue once you speed things up - (and as I said 'elsewhere') you really should consider retro-fitting the carb even if you have to rig-up a gravity feed to it and see if the problem still exists. Perhaps it's some form of electro-magnetic interference from the ignition that's affecting the Sniper ECU?

 

[Dazaa]

Possibly yes, I may have accidentally poured a can of stale fuel in the tank , need to drain it and try with fresh fuel and the new plugs
Thinking back even when It ran with the carb there was always a slight misfire at idle which was confirmed by a video I took, I knew a lot less then than I do now (and I don't know much now!) so wasn't paying a huge amount of attention as I was just so excited to hear it come to life. Both of the carbs I have seemed to have issues with idling down below 2000rpm so wouldn't be much help unfortunately. Re the EMI issue, theres a lot of electronics in my car with electric fans, digital gauges, fan controller, gear position sender,vintageair hvac kit and msd ignition so it's certainly something i'm going to investigate.

 

[Knodty]

Possibly yes, I may have accidentally poured a can of stale fuel in the tank , need to drain it and try with fresh fuel and the new plugs
Thinking back even when It ran with the carb there was always a slight misfire at idle which was confirmed by a video I took, I knew a lot less then than I do now (and I don't know much now!) so wasn't paying a huge amount of attention as I was just so excited to hear it come to life. Both of the carbs I have seemed to have issues with idling down below 2000rpm so wouldn't be much help unfortunately. Re the EMI issue, theres a lot of electronics in my car with electric fans, digital gauges, fan controller, gear position sender,vintageair hvac kit and msd ignition so it's certainly something i'm going to investigate.

I started getting a misfiring issue after I got the car back from Car SOS. I ended up changing the MSD for a Petronix ignition module. No more problems. The msd unit was only 5 years old but my under hood temps are quite excessive, So that might of contributed to its failure.

 

[Forrest Gump]

My mate has recently fitted Holley Sniper EFI to his Plymouth Duster. He was the last person I thought would turn away from a conventional carb set-up as tuning Holleys has always been his thing.
He too found the installation not so straight-forward, I think he decided his alternator was not up to it was and causing a voltage related fault. Electronics are certainly voltage sensitive.
He's got car the car running now. It seemed to have a mind of it's own during the "learning phase" but with that completed he reckons the performance has definitely improved. It also now makes an audible "whistle" when you step on it.

I was over at Tom Newmans recently and he said that he was fitting EFI more and more to his customer engines. Often an LS and bound for hot rod / resto mod cars.

 

[CaptainK]

Not long after I got my car I wanted to replace the intake and carb. I did look at EFI systems, cost, and fitting complexity etc. I decided i would love an EFI system, but the extra amount just wasn't worth it. I mean I don't use the car that often, so fuel cost is irrelevant, however the extra £1 - £2k costs of buying the EFI system and getting someone to fit it for me (outside of my skills), just put me right off. There would be no way I'd be able make the cost back over my lifetime of use of the car.
Though I may just go for EFI in many years time anyway, when it gets a lot cheaper etc. But for now, I'm happy with my carb setup.

 

[Vetman]

I posted some months ago after I fitted the Innovate oxygen sensors and a dual air fuel ratio gauge to my 1975 L48 350. A lot less work and cost than EFI but provides the same feedback that the EFI computer uses to adjust the squirt.

I used the gauge to make minor carburettor adjustments and the car runs very well with AFR values where they need to be, about 12.5 to 14.7 most of the time, which is good for performance.

My car starts quickly despite the mechanical fuel pump when I give the accelerator a pump. However, I prefer it to turn over and show some oil pressure before it fires up. This ensures the oil is where it needs to be beforehand.

Photo of gauge during warm-up.

 

[oldmemberl68]

Ive fitted a couple of jenvey fi units to v12 jag e types using emerald ecu and there are not straight forward to fit and will not work correctly unless you fit a high output alternator we get emerald to do the final set up once we get them started . They start from cold very well