Soon I will purchase a B20 which once had injectors on it. My 122 has a B18 with SUs. The 122 will get the B20 after a rebuild. My question is for those of you who have had both types of carburation . Which do you prefer and why?
I've been treated well with the B18/SU set up, but I'm not afraid to graduate.

i have 25 years working with fuel systems on classic volvo cars . so i guess ill reply to this one . old fuel inj can be a real problem at times unless you replace many of the parts relating to electronic or efi as we call it or j tronic. the system as it came on 1971 p1800 and 142e cars is a performing system when in proper tune, we race improved touring 71-142 w/fuel inj and it must be oem,with some success and reliability.but if you just want to enjoy your classic volvo and not spend lots of money then have joe curto rebuild your old su caurbs ,get a big valve fuely head and block of the inj holes . get quality 3 angle valve job . well on my 72 142s i did this fuel inj head w/su caurbs and i feel almost as strong as the b20f power in my 72 1800e . blueryder45@yahoo.com is dave spano cert.volvo tech cert.mercdes tech 25 years

I have D-jet in my 122 and it's fine. It would be better if I put some effort into it but that's going to have to wait another year. But anyway, I've read enough on this board and elsewhere to be convinced that some programmable EFI system is where I should be looking. As John pointed out, I've already done the hard stuff for this. But anyway, yes, it's fine and totally bulletproof as long as I can keep from messing, which is not easy.

I also have a 145 with HIF SUs and love them. Very simple little things compared to the Demonic-Tronic in me 122. If I were you I'd stick with the SUs. I have a higher opinion of D-jet than others, but it's probably not your best choice right now.
--
Justin 66 122E, 71 145S
Read vclassics!

I reckon I'm with the rest of the folks in recommending you stick with SUs...just for the ease of it.

THe one thing that either didn't get mentioned or I didn't see... what year B20? it could have been set up for either Djet, or Kjet depending on the year.

I've seen a few Djet 122s... is there a good reason I've never seen one that has been converted to Kjet? Seems like it would be a bit easier and more reliable than the electronic system...

-Matt

Here's one with K-jet. I'm pretty sure I've got better pics of it that this someplace, but I'd have to dig pretty deep to find them.

Phil,

Is that Lee Corder's "Volper"? I know Lee has the K-jet system in his highly modified 122.

Lee (national president of VCOA) participates in the Brickboard discussions, doesn't he?

I've always wanted to asked exactly why he went with the K-jet over the D-jet.
Lee, are you there?

gary

Hey Gary,

Yes, that's Lee's Volper. I don't believe he's on the board often, though.

I think the idea was to keep it simple, and perhaps also to do something a bit unusual. There's some ingenuity involved in fitting all that into a 122.

In the pic below, Lee's about to make a light snack out of my 1800 at Thunderhill. Now, that was quite a few suspension, wheel and tire mods to my car ago, and with me running a free "mule" motor donated by a car we parted out. Haven't had a chance to run with him since, but I think he'd find getting by a bit more of a challenge these days...

--Phil

Looks spiffy... That would be the route I'd take if I were to bother with injection. I don't know about tunability for performance applications, but heck... they did use Kjet on some '70s V12 Ferraris...

-Matt

"Amen" to JohnMc's remarks. In fact "Amen" and "Amen" since his reply came through twice.
Bob S.

Well, you have to weigh the incredible ease of just bolting the SU's on to the not trivial task of installing all the D-Jet electricals and extra plumbing.

All in all I'd have to say that D-Jet (in my experience) is a cleaner running, less tweaking and slightly more powerful setup. My thought is that D-Jet vs. SU's on an identical engine (well, stock at least) will make slightly more power due to the tuned plenum and 4 long straight wide open intake runners. I think that manifold adds a little more low-to-mid range torque.

However, SU's can be tweaked to keep up with a modified engine somewhat more easily, at least using the skill sets most of us shade tree mechanics have. The advantage D-Jet would have is that with all the 'infrastructure' already on the car you are that much closer to putting a modern programmable FI system like Megasquirt on.

John;

Although I have nothing whatsoever against D-Jet, I totally agree with you on this. There's not that much performance, if any, to be gained with D-Jet, and I bet I can find and fix any problem a whole lot quicker (and much more inexpensively! *) on my SUs (as rarely as I need to!), than the much more complicated injection system!

* I bet I can two whole (good) carbs and linkages for what a major FI component will set you back!

Cheers

Well, you have to weigh the incredible ease of just bolting the SU's on to the not trivial task of installing all the D-Jet electricals and extra plumbing.

All in all I'd have to say that D-Jet (in my experience) is a cleaner running, less tweaking and slightly more powerful setup. My thought is that D-Jet vs. SU's on an identical engine (well, stock at least) will make slightly more power due to the tuned plenum and 4 long straight wide open intake runners. I think that manifold adds a little more low-to-mid range torque.

However, SU's can be tweaked to keep up with a modified engine somewhat more easily, at least using the skill sets most of us shade tree mechanics have. The advantage D-Jet would have is that with all the 'infrastructure' already on the car you are that much closer to putting a modern programmable FI system like Megasquirt on.

I agree with John. If you have the SU's mastered there won't be too much of a power or economy advantage conveyed by fuel injection. Fuel injection is much better for dealing with a cold engine/warmup driveability.

The important missing metric is the 'cool' factor of fuel injection. Something new to figure out and tune. If you do decide to go with fuel injection go with something programmable (SDS or MegaSquirt) instead of OEM bosch systems. There has been a lot of progress in the last 30 years in the computer field :). Costs are roughly equivalent.

steve