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Easiest replacement for my B21-MPG

Mark G

STARTTLS
Joined
Dec 9, 2009
Location
Vermont
Not looking for a race engine (at least not in the immediate future :ninja: ), but I would certainly appreciate a motor that puts out over 200 bhp. The current B21 / M46 / 3.54 is already growing old on me.

What's the easiest way to replace this setup with something that makes in the 225-250 range? Even 200 would be a huge improvement. B230T out of a totalled 940?

I'm assuming the M46 is not going to last all that long if I'm trying to live at double the factory supplied horsepower and torque for this car. Is a M47 worth swapping in or do I wait until I have the funds to consider a T5 swap?
 
+turbo wih intercooler what you have.

Good start and easiest, but gas mileage will suffer. All other steps get a LOT more involved since you are dealing with a K-jet car, and the non-turbo version at that.

My suggestion for that power range and better gas mileage? B230F engine from the newest volvo with that engine (90 and up is ok, but 93 and up would be slightly better)

Add a 15G turbo from an 850 with all the parts from a 90+B230FT. Larger exhaust from turbo on, like 3" mandrel if you can afford it. Swap out the K-jet to AT LEAST LH2.4 fuel injection and then chip that. Better step for EFI is to go fully programmable with Megasquirt or equivalent.

The M46 should be fine with the HP levels you are considering, and with a 15G, the torque wont get too crazy. And tuning would be key, but the whole process will take a while, and depending on skill level and budget, may be a steep learning curve and not really cheap.

Good luck on what you decide, others will provide more info or ideas as well.

PJ
 
Seems like this is a $2K+ proposition at this point. Car actually has brand new exhaust and was converted to the Bosch distributor by the PO. So, putting in a new exhaust system isn't something I could justify on my current budget.

I had originally bought the car to be a daily driver, and not as much a long term project. Are there any changes I could make to the current engine that would make a noticeable performance difference? I've been searching through other threads and the topic of swapping the cam was mentioned. However, none of the threads seemed to be conclusive if the swap was worth the effort, or what cam would be most beneficial.
 
If you want something quick and fairly easy, you could put a 4:10 gear in it. It's cheap, and you'd be surprised how much it perks up. If you have dreams of 200+hp, you should probably save your pennies for that $2K+ investment.
 
You can get that level of power with your current engine, but it will involve a good bit of modification.

If you don't want to go to the trouble/expense of adding a turbo, a B cam will make a difference. PM me if you need one as I think I have a spare.
 
Are there any changes I could make to the current engine that would make a noticeable performance difference?
Cam swap. Ditch the M cam you most likely have now (did the MPG engines get a B cam??), and in my opinion I'd swap to either an A, B, or K cam.

I'd leave an adjustable cam gear out of the equation for now, with 98% of the stock cams it's all but useless bling IMO. If you had a low SCR and a bumpier cam (like 7.5:1 with a K cam), then I'd suggest it.

As stated above, swap out the 3.54 R&P for the 4.10s. If nothing more it'll make 1st gear in the M46 even more useless, but 2nd and 3rd will be fun.

Could also play around with ignition timing, that won't cost you anything but time...no pun intended. Hotter coils and lower resistance wires, better plugs, etc could all be utilized as well, but return on investment is minimal at best in the ballpark you're playing in right now.

Since the exhaust is new and you're trepid about modifying it, I won't touch on that subject except to say that improving the exhaust is the foundation for all other modifications. Think of your engine as a giant air pump. The easier it is to move air through it, the more efficient it will be.

An e-fan conversion will be most noticeable in the reduction of overall engine noise, and may make it a slight bit peppier.

Open element / cone filter intakes, most noticeable in the increased engine noise. Modifying the stock airbox (disable the TAC flapper valve, remove the choke points in the box, etc) will be 'free' mods and net about the same results, minus some of the noise since the filter will still be enclosed in a housing.




Anyway, this is all just my two cents; take it with a grain of salt. Do whatever you want, it's your car. You're the one who has to drive it. ;-)
 
Thanks to all of you guys for replying so far... lots of good info. As far as the A, B, or K cams, what are the differences? Are some easier to find than others? What's a good price for one? I think an open element filter and then a cam may be the first two power mods I consider.

As far as gearing, is it possible to swap out to a LSD with a better ratio? I'm assuming this is also prohibitively expensive, right?
 
Thanks to all of you guys for replying so far... lots of good info. As far as the A, B, or K cams, what are the differences? Are some easier to find than others? What's a good price for one? I think an open element filter and then a cam may be the first two power mods I consider.

http://www.turbobricks.com/resources.php?content=camspec


As far as gearing, is it possible to swap out to a LSD with a better ratio? I'm assuming this is also prohibitively expensive, right?

That's what Corsair was talking about with 4.10 gears a few posts back

If you want something quick and fairly easy, you could put a 4:10 gear in it. It's cheap, and you'd be surprised how much it perks up. If you have dreams of 200+hp, you should probably save your pennies for that $2K+ investment.
 
I didn't realize LSDs were commonly found in Volvos.

Common is a funny word. There has been much discussion of options for the rear end recently. It can get spendy if you want some of the nicer options. The r&p gear can be done with or without an lsd. 1st gear will go by real quick, but you will really like what happens to 2nd and 3rd. imo, gears are great bang for the buck.

Open lsd isn't so bad if you can't find/afford an lsd at the moment. With an n/a car you don't lose traction as frequently as you do with a turbo. If you can grab the car by the scruff of the neck and shove it around, it'll go faster than any speed limit in the land stock as a rock.

Point being, grab a gear if you want some more grunt, but if $2K for an engine rebuild sounds daunting, you may want to see what you can do with a mostly stock car. It may surprise you.
 
Isn't K-jet the injection with the big fuel distributor (I used to know is as CIS)? If so, I have the fuel parts off a turbo 240 one; saw the box last week.
 
I sold the 1981 242 in question 5-6 years ago? And I know it's been sold at least once more since then. I still sort of regret selling it. It was my daily pretty much right until I sold it, and I never had the opportunity to +T. Nevertheless, it was a fun car to drive.
 
I sold the 1981 242 in question 5-6 years ago? And I know it's been sold at least once more since then. I still sort of regret selling it. It was my daily pretty much right until I sold it, and I never had the opportunity to +T. Nevertheless, it was a fun car to drive.

Classic tb. :lol:
 
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