Cost of ITB vs PMO (or similar) carbs?
 

Good morning - it is just my faulty eyes or have the costs of a new ITB set up decreased to a point where it is getting to be close in total cost to new PMO carbs or used Webers + rebuild and jetting?

Opinions will vary, which is great, but doesn't that actually make the ITB set up cheaper over 5-10 years of ownership assuming you have a shop do the tuning on carbs on an on-going basis?

I'll duck for cover now and keenly await people's perspectives.

Thanks!

I think it depends on what setup you currently have and what you're going to. If you already have carbs, an ITB/EFI setup even on the cheap is going to be a lot more expensive than repairing your carbs as you're going to need to swap fuel pumps, possibly the fuel tank, pick out an ECU, tune it, etc.

My Webers were leaking everywhere and, after struggling to get a local shop able and with time on their schedule to repair/tune them, decided it was now or never to go EFI. I spent roughly $15,000 (with a bunch of other "while we're in there" costs) for my conversion, which included a brand new fuel tank, new fuel pump, new lines, pressure regulator, Clewett ITBs, coil-on-plug conversion, ECU Masters Black Emu ECU, new wiring, cam sensor, crank sensor/trigger wheel, then ultimately a dyno tune and probably a few other items I forgot.

I know there are a lot of DIYers here which could likely have cut my cost in half so that's obviously a consideration if you aren't a ham-fisted home mechanic like myself. I also get that not all conversions are going to include revamping the entire ignition system.

I'm guessing rebuilding and tuning the Webers would have run me a few grand by comparison.

A before and after:

http://forums.pelicanparts.com/uploa...1675792791.jpg
http://forums.pelicanparts.com/uploa...1675792791.jpg

I don’t know much about carbs or PMO but you can get from CIS to an EFI ITB set up for around $4000. Less if you can seek your CIS; I sold mine for $900 thus reducing my conversion cost. Of course, the sky is the limit and you could easily spend 10 times that much if you so desire.

RHD ITBs: $2400 with rain hats, ($2000 without)
Megasquirt: $659
Harness: $99
AFR sensor: $100
TPS: $30
Fuse panel: $20
FPR: $100
Fittings, hoses, wires, etc: $200
Temp sensor: $30

That’s a basic kit that doesn’t control timing, you can add that if you like or add it later.

Total cost $3639. So round up to $4k because I know I forgot some stuff and there you go. EFI/ITB for less than the cost of a set of core carbs or PMO.

Cheap CIS->EFI costs about the same as CIS->Carbs
Expensive CIS-> EFI costs almost 3x the price of CIS->Carbs

EFI starts at approximately the same price as a carb conversion, but the prices go up dramatically from there. There's a lot of little add-ons. For example, where are you going to get your cam position from? Crank position? Gotta buy those sensors. Your existing fuel pump - does it produce enough pressure to support an EFI system? What about regulation of the fuel pressure? Do your fuel lines support the E85 tune you're thinking about running? The throttle bodies you're using - are they electronic? Guess you need a TPS. Oh, they're dual DBW throttle bodies? Damn, now you need an ECU which supports dual DBW, since most don't (or a little adaptor box). How are you going to handle the vacuum system for your power brakes and fuel fume extraction? Do you want your ignition controlled via the standard dizzy and CDI, or do you want coil-on-plug/coil near plug? If CoP, smart coils that're powered directly by your ECU, or do you need a ballast box? What're you doing for air filtration, and does it have a hole for your charcoal canister? Do your new throttle bodies fit with your A/C compressor? Are you okay with losing your heater fan in the engine bay? May need an aftermarket fan to compensate if you're dissatisfied with backdated heat. How about your Wideband - you've got a bung welded into your exhaust for it already, right? And your ECU supports it without a translator box? Your electrical system's all up to snuff? Where are you going to put the ECU, and does your ECU harness include enough wire to support that location? If the ECU's going inside the car, how are you running the wires, and what disconnects will you have?

Nothing insurmountable, just a ton to think about. You can end up buying the same components twice if you want to upgrade some aspect of the system in the future. I went carbs with my build. As a weekend car, it was the right choice. I love to tinker, and they look (and smell!) so good. Unfortunately, this isn't my weekend car. This is my only functional car. My daily driver, in 120*F or -20*F. And the 8.6MPG, lack of choke/cold idle, and lower power than a similarly priced EFI system isn't endearing it to me for this scenario. I shoulda gone EFI.

$4k is a pretty good ball park for EFI conversion starting point. with no fab skills and wanting top of the line, I could see $12k towards the top-end.

There's a build for every budget.

Thanks for the response and discussion, very much appreciated.

I should have mentioned up from that I’m considering this for a 3.0L with factory CIS, sorry.

Sound of my carbureted 911 engines is intoxicating but kind of want to a turn the key and off you go experience. Not looking for max power or race performance. This engine is going into a lighter car anyway…

So in my case I’d need to acquire and hit the carbs which seems to make ITB not that much of a swing, installation etc notwithstanding.

Ultimately I think one of the biggest factors in any CIS conversion is whether or not you are doing the install and tuning yourself. If yes then you can keep the costs way down (and learn a lot and have a lot of fun and be super frustrated at times and invent new swear words) but if you’re paying for the install or tuning, be prepared to spend a lot more.

I asked a local air cooled shop about the cost to install an efi system that I provided and they quoted at least $5k on top of the cost of the parts!!

Going diy was the key to making the maths work.

PMO new pricing from EMPI could make ITBs a lot cheaper choice

I love ITB’s but they aren’t cheap. Good EFI is expensive. Then add in the custom wire harness and tuning. If you try to buy cheap EFI, it’s just as costly because you will pay more on the back end for more hours of tuning and tech support.

Great discussion gentlemen, appreciate the experience/perspectives.

If you can’t tune yourself whether it’s carbs or EFI and you have to ask how much? your better off sticking with a properly tuned/restored cis, just my dumb opinion. Your Webers shouldn’t have to be tuned every 5 minutes either if properly restored and set up.