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B21+T Questions

TouringMusician

New member
Joined
Jan 19, 2014
Location
Colorado Springs, CO
Apologies if this has been covered many times before. I?m experienced with 240s but not with turbo at all.

I can score an ?82 245 manual in colors I love for almost free-it?s got a bad wiring harness and someone took apart the kjet. It?s a very stock NA b21. How much further around my elbow would I be going to try to do a late model EFI +T setup on this? I?m guessing mechanically, it all bolts up, but I?d be missing stuff like crank sensor, incorrect fuel pressure, etc?

Just curious if it?s worth my time to eff with the b21, or if I would be better off cutting my losses for a later setup. In my head the little b21 with the thick rods/cyl walls and 9.3ish compression sounds like it?d be a fun, reliable daily in the 9-10psi range, but as I said, I have zero experience with turbo cars. I?ve had a dozen or so NA.

Thanks!
 
Flat top piston B21 is a lot of compression for a turbo motor on regular gas for most use, though maybe on super at CO 8k feet it wouldn't be so bad, IDK?
Thin HG/tight squish, IDK?

B21 is kind of the better engine in some ways; narrower bore to resist detonation, no piston slap, super tough for what they are.

Tough break tho; if you want turbo power, factory turbo car/engine might make a lot more sense/be better value if you can find one with minimal wear if this is to be an all-junkyard budget TB endeavor.
Good deal on the big bumpers at least!

K-jet strangling the engine with the airflow plate/low compression at high elevation, ouch!
That said, for cold weather, K-jet is better than EFI in a lot of ways (variable nozzles spraying at backs of intake valves/no waiting for coolant/intake ports to warm up). :lol:

More control pressure/more restriction on the factory altitude-compensating 84.5+ 240TIC to lean the mixture appropriately in WY/MT (8Kft elevation also, but colder/denser air (glacier) sans thin HG/compression up from factory quoted 7.5:1 to just under ~8.5:1 didn't make for inspiring off-boost economy/performance in stock form, even in good repair. :rofl:
Think 14mpg/same as the land rover V8 british POS with AW-71 :lol:.

But you'd hate to paint yourself in a corner/take a road trip in hot weather to sea level and have it ping itself to death if it's optimized for super fuel & cold dry air @ 8K feet for power/economy, right?

LS swap?
LH1.0 33mpg (probably not that good, those steep hills/thin air/winter warmup time sans block heater/water cooled turbo to get the coolant toasty fast is a tall (literally) order in CO) gutless hiper-miler '82 CA B21F-EFI?
Other than #rare parts, have a soft spot for how good those are on fuel sipping/horrible quality CA gas/no EGR/horrific emissions devices (vac pumps, smog pumps, miles of vac lines) + big bumper practicality as design considerations/constraints.
 
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Flat top piston B21 is a lot of compression for a turbo motor on regular gas for most use, though maybe on super at CO 8k feet it wouldn't be so bad, IDK?
Thin HG/tight squish, IDK?

B21 is kind of the better engine in some ways; narrower bore to resist detonation, no piston slap, super tough for what they are.

Tough break tho; if you want turbo power, factory turbo car/engine might make a lot more sense/be better value if you can find one with minimal wear if this is to be an all-junkyard budget TB endeavor.
Good deal on the big bumpers at least!

K-jet strangling the engine with the airflow plate/low compression at high elevation, ouch!
That said, for cold weather, K-jet is better than EFI in a lot of ways. :lol:

But you'd hate to paint yourself in a corner/take a road trip in hot weather to sea level and have it ping itself to death if it's optimized for super fuel @ 8K feet, right?

LS swap?


See this is the info I need! Thanks! I was curious if that CR was too high? I figured it wasn?t since I?ve seen so many +T b230f cars, but maybe I?m missing something. I?d hate to put that much work into it and have it be for naught. I?m expecting to run premium, but I?d like to be able to leave Colorado if I want to haha!

I?d be really interested in more thoughts about CR vs reliability/knock/etc.

I?m also not against just doing something else, but I figured the 82 is enough of a dog and already missing fuel stuff, that why not finally join the +T dark side...?
 
Most of the '82s I've had have had an L-cam, which makes same power curve as the M does on the 2.3 basically/designed to squeak by CA smog for NOX without horrific smog pumps/EGR devices/band-aids or variable timing complexity, but w/B21.
Horrible. Swap in a T at least if you don't have to pass strict CA smog/Nox.

Tough decision for broad spectrum of use.

In your shoes, I'd want to find the compromise for cold weather, good power off boost, and maybe some more power to climb those steep hills in light boost/lean burning, but basically quasi-altitude-power-loss-immune that boosted motoring can provide + fast warmup time of a water 'cooled' (jacketed?) turbo maybe if recombining the stock volvo junkpile on the cheap without necessarily requiring block heat for longevity/economy?

No idea what that is.
I had a 240Turbo already and just installed a ridiculously thin headgasket/ported the head/did the 90+ manifold conversion.
Didn't want to have to know/do anything special & still run regular gas (or do they sell 85 octane/more volatile fuel in CO like they do for high-elevation in WY & MT?)

N/A B21 is kinda a tough one/lost soul tho;
Doesn't have the compression of the flat top piston B23 for N/A use or B230E nearly flat top pistons.
Doesn't have the lower compression of the B21FT to really beat on it/still run regular gas flying blind/no knock sensor or precise ignition control (mechanical dist).
No exactly ideal factory fuel system that matches it all that well for spark/fuel for N/A high compression use, or turbo power.

B21 is an interesting smog-era evolution of the B20, they did pretty well for the time/it's not junk/wouldn't necessarily abandon it, but maybe hard to use optimally for what you want to get out of it?

With an efficient D088 style intercooler, 3-row radiator, TIC pusher fan (is it to have A/C heating the charge air even more?) & good strong tropical fan clutch/air pickup on the big bumper air dam (if you've got brake cooling/ducting/vented brakes if you block all that air with the airdam/air pickup) & thin HG, it might not be a total pinging mess at lower boost on LH with appropriate spark curve & still able to venture to the coast/climb back up the hills for a summer vacation?
Ported 90+/cosworth style exhaust housing/no cat DP helped a lot with engine bay heat on the stock 240T.

Would you use the factory 240T oil cooler/non emissions friendly T-stat & do the piston oil squirter mod/late model oil pump to *try* to keep the pistons a little cooler?

How much recombining/turd polishing/work-arounds?
 
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Conversely, is there a known resource for possibilities of a high comp NA via decking the block? I know there’s math out there for a tight squish b230, but is there any logical avenue for that on a b21? I figured since elevation is such a thing here, it’d be hard to calculate that precisely, since I live at 6000, but may drive anywhere from sea level to 12000.
 
And just to be perfectly clear, my goals aren’t a monster car, I just want a very reliable daily that’s noticeably more spirited than my 1993 NA.

A B21+T can achieve this, but will take more effort to get there than doing so on an existing EFI car.

In your case, I don't think I'd put the effort into resurrecting the B21. I'd consider pulling that engine out and putting in a B230FT and converting to LH2.4 / EZ-116K in the process (you have to replace the harness anyway). The B230 block has provisions for the crank position sensor and you can pull a whole engine/ignition harness from a newer 240 (more readily available), but you'll have to figure out a VSS signal source for LH2.4 on the 82.

I've never driven a high compression n/a Volvo engine, but with your wide variation of altitudes, I think you will be better served by a turbo engine.
 
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^IDK, B230s are kind of garbage; short little pistons, larger bore, cast crank, hoooorible rubber damper pulley, worse quality control (no more Bofors military subsidy/facility waste production).

Low boost + intercooled with appropriate spark control + late model oil pump + squirters, B21F+T is probably technically a better/as good choice of the redblocks really?

Older/harder to get certain parts for though in some ways to build it in quality, though that's about to be true of the B230s too probably/both obscure with a pipeline of chinesium if anything?

You can definitely deck the block to tighten squish & use the stock HG, not a bad way to go.
If you have access to competent machinist hands at reasonable cost where you are, a healthy/minimal leakdown/blowby B21 & the squirter kit? :e-shrug:

Might want an SCP head to stick atop the B21 there, EFI maybe, IDK?
 
I don't know, it seems like a +T conversion on a B21F (9.3 cr) would be pretty similar to a +T on a B230F (9.5, or 9.8?, cr). You'd need to use premium (93 octane around here) and keep the boost lower for reliability (but Denver's only at 80kPa to begin with, so a bit higher boost if you stay local should be OK). Unlike the flats, you need to worry about being in boost for 30+ minutes continuously as you head up I-70 into the mountains

To convert to LH2.4 Turbo, you'll need the turbo parts off a 740T or 940T, including T cam, intake, ECU/EZK, injectors, turbo, intercooler, hoses, etc., plus a 240 TIC fan shroud (not cheap) or efan. Most likely, you'll need to machine a custom CPS bracket. You might be better off finding a reasonable donor 740T/940T and just swap everything.
 
fair points Kjets...a B21+T isn't "wrong", but takes more fiddling (IMO) vs dropping in a stock B230FT running on stock EMS.

Exactly; devils in the details, all redblocks are old by now, so at some point it becomes a distinction without a difference between trying to build/get parts for any of them with consistent/decent/repeatable lasting results?

Less repeated path than slap it together in a weekend TB B230FT donor path & constantly babysit it until crush-it in ~6-36 months like much of TB, but not necessarily meaningfully worse or more difficult trying to go +T on an N/A car recombining the stock(ish) junkpile all told given the scope of things/challenges?

Narrow bore/better metal/thicker cylinder wall flat-top piston B21F isn't necessarily a demerit? :e-shrug:

Oil squirter+late oil pump B21FT w/decked block/somewhat skimmed/ported SCP 405 head/re-indexable timing gear w/stepper motor on k-jet metering pin & beat the snot out of it if recombining all junkyard kool-aid/mild setups compatible with regular gas with way too much $ into it per HP compared to 16V &/or V6/V8 swap, possibly, all told?

I guess the constraints there would be mostly all-used junkyard & SOHC redblock/ 240Tesque?

Don't build your car/TIC convert or not because you're such a volvo whining entitled cheapskate dirtbag lowered lowlife that the slight increase in price non-inflation-adjusted of a TIC fan shroud stops you? That's the deciding factor?... :run: :lol: :rofl:

You guys have the window stickers from the intercooler option in the 80s and how much that'd cost you inflation adjusted for a lousy +~37HP (which was significant then) now, right?
What's the complaint, again?
There are a lot of weird little parts that are 240TIC specific, but usually have acceptable substitutes...to a degree.

Most of the B230FT cars are owned by the 1st owner that are still driving it/grandpa/grandma silver-hair at this point.

or

total dirtbags, zillion miles, squirter motors run at the ragged edge of nuclear-meltdown overheat on the e-fan cars, or if not squirter motor, tons of slap/tons of blow by/oil use/barely any compression left lubricated by ~1-2quart(s) of roofing tar.

Maybe the under-stressed narrow bore/tall piston B21F with minimal blowby isn't such junk after all with the test of time of average used junkyard motors? :lol: :e-shrug:
Or hope grandma dies/wrecks the 7/9 for a mechanical donor? Kind of macabre wish / vulturistic :/
 
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Thanks to everyone for all the great input. I’m learning a ton!

For what it’s worth, I’m not a typical TB cheapskate, just a normal cheapskate. I’ve driven the same 245 for a decade because I’m sentimental and hate junking cars, but I’ve also owned a ton of cheap Volvos and have def repaired mine at a TB quality many times haha. My car is beat, but I don’t abuse it, if that makes sense.

Anyway, I like the robust nature of the b21, esp since most of the b230fts I run across are nearing the end of their life, and this is an under 200k b21 in what looks to be a well maintained car. But I think the disadvantages of the car not playing well with the newer EFI harness and sensors.

Just for curiosity’s sake, is there an EFI that doesn’t need CPS? Were there LH2.2 turbos?

Also, since I don’t know what I’m talking about, how necessary would the squirters/pump upgrade be if I were just running stockish psi?
 
^Sure, all 700Ts -1989 had no CPS/LH2.2 turbo.

Prefer LH2.2, not because it's 'better' any meaningful way, just simpler/no adaptive memory.
Lower resolution w/o CPS though and everyone here wants to install 2.4 and 'chip' it or jack around with it all to end up having the emissions/adaptive memory obliterate any consistent results and barely make any more than low/mid 200s for power with ridiculous compromises anyway :e-shrug:
Rather just accept the limitations of the LH as delivered than turd polish it or make longevity/other compromises?

That, and everyone wants to kludge the 2.4 harness in there complete/can't read a wiring diagram and buy/borrow basic terminal tools, apparently?
There is no LH2.2+EZK harness drop-in for 240 chassis + stock 240 block dist exactly that uses the peak & hold low-z injectors of the 700Turbo, if you find those to be major impediments.

NBD I say, drill/tap the knock sensor spot and recombine/make one, but wiring done carefully is time consuming/takes some care, tedious. I'm not that good at it/can make it fit/only fake-it more or less as well as antiquated connectors/harness laid out on a peg-board late 60s/1970s style as volvo more or less did +EFI in the case of the 80s 240s? :e-shrug:

Even a bone stock well cared for 2.2 the car never runs totally consistently to tune it on a dyno the same now that all the old used MAFs are all old and half clapped out/no 2 are exactly the same.
Tho if you find a replacement Bosch w.Germany MAF and don't cook it, they go a while?
Turbo/more airflow total/more stress/plumbing at this late date doesn't help though?

You don't "need" the squirters or later oil pump.

Late oil pump and pipe is nice/taller gears/nice revision volvo did there, but lots of B21FTs that are well cared for running around that still basically work as-delivered.
Turbo is a lot more heat/stress is all.

Hotter pistons make the engine more detonation prone, but squirters also increase oil cooler BTU-exchange load & froth the oil, which may or may not be what you want.

Late ~88-92 tight oil pump+ matched pipe to go with it is a drop-in improvement is all/easy enough to do if you have it on the stand and you're figuring out the turbo feed/drain anyway? IDK?
Might need the pan off, some seals & transfer tube seals anyway at this late date, especially if adding a lot of turbo parts to add more heat/stress to an already old/used junkyard engine that's sat a bit?

Low boost/lean burning around 0 boost/more power off boost for high elevation use probably good compromise?
 
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I +T'd a B21A, which was 9.3:1, and had no issues at all. Heck, the B6304S I +T'd was 10.7:1 and when I pulled it out it was still in great shape, even after being run without an intercooler. 7 psi and premium fuel (91-94 octane) were all it saw, although I did have an AEM water/meth kit. All it did was drown the AFRs though, so I had it set extremely low.

High compression and boost is great, it just takes more care, that's all.
 
I ran the lh2.2/EZK swap on my B21+T but I also had RSI turbo pistons which were supposed to drop the CR to 8.5-1. I eventually microsquirted it and was running 24psi until the DW300 in tank pump locked up and it ran lean and exploded. I beat the shazbot out of that engine and it would probably still be running but for the fuel pump. At one point I was running a .100" thick Cometic HG in an effort to reduce CR due to the head being cut too much. If you take the engine apart you can CC the head after machining to determine your CR and go from there.
 
Kinda off topic, but can anyone educate me on what made the b23e so powerful? I’m finding CR spec to be 10.3:1, which should be the same as b23f in 1983, correct? Was it just a better cam, or did it have a different head?

Curious if upping compression to safe premium fuel levels is worth it on a b21 if it was kept
NA?
 
H or K-cam/405 head.
Idles ~12-13:1 AFR, won't pass emissions.

Not that impressive in some ways with the K-jet strangling it so badly.
It's 140Hp? in the Aus H-cam GT instead of 114 or 120 in the much milder cammed engines that pass emissions/&/or have MUCH more usable torque/economy.

That said, with the OE N/A K-jet plenum intake, if you got the ridiculously restrictive K-jet plate out of the way and straight thru mufflers/still quiet/still OE manifolds & ported head, 170Hp should is known to be very possible N/A Volvo Original Cup guys style more or less (they're stuck with K-jet plate per rules IIRC, I forget?)?
You probably could ditch the K-jet plate and have pretty usable torque since you aren't bound by VOC rules for a street car.

All north american market 405 Heads are BCP, which is sort of tragic/buzz kill for boosted use + 2.3L 96mm bore. :/

.100" HG with pistons at 0? deck + heavily squish pad-reliant cylinder head design? :lol:
While it's true that as you shave the head, it un-shrouds the valves more for flow, it might also make it interference, and if you're band-aiding higher-than-desired compression w/proprietary metal headgasket that's absurdly thick, that's...maybe its own issue :lol:.
 
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