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Discussion Starter #1
I am researching the b20/vtec swap and was wondering if it would be a good idea to bore the block. I do realize it already sits at 2 liters, but it seems to me that more couldn't hurt. This may be a dumb question, but could you run into problems with insufficient air supply through the IM? I suppose that could be changed accordingly also. How much could you bore if you wanted to?

So basically, if there is no replacement for displacement, then why don't I read about these things being bored and reinforced? Unless there is something I am unaware of, that would be a badass setup. Could you imagine the monster?

Woody
 

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its not all about bore and how many liters u can sqeeze out these 4 cylinders. There is a reason u dont hear people doing this its because it is not worth it. U have to consider rod ratios and stroke and other things play a vital role. If u want more displacement I suggest u get a 454.......
 

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I would not exceed 87 mm or else the pistons would practically be touching each other with paper thin cylinder walls. You would definitely have to re-inforce the walls with support "tangs" like the ones you see on the Golden Eagle sleeves. DART (through Payne Technologies) sells big bore blocks if you want to exceed 87mm. DARToN sleeves would have the same 87 mm limit.

There are pics of these in the Performance Articles, Engine Internal Section under my article entitled "Engine Package II: Swapping Parts for Power".

I would not force induce or use nitrous on an 87mm bore.

So with 87mm bore and 89mm stroke (from the B20 crank) you would have 2116 cc displacement with 1.54 rod ratio (don't rev past 8000 rpm if it's a daily driver).
 

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Discussion Starter #4
I don't know the different stroke lengths of different cranks. So, if the block is bored to 87mm, is there any way to raise the rod ratio appreciably while only droping displacement back down to approx. 2.0 liters? I ask this because before boring the rod ratio is still only 1.54. Correct??? So you have a 2000cc engine you have to keep below 8000 rpm. If you bore it, then put in a different crank or rods, we may be able to make once again a 2 liter engine, but this one may go to 9500 rpm safely. Again I don't know the numbers like MD, but would like to know if this would work. I understand that FI in not a good idea were it bored, but for N/A this might be sweet.

MD, if this is a useless endeavor just tell me so. I really want it to work, so I am doing my best to find a way. How much more power would come out of 1500 more rpm? maybe it isn't worth the effort. but I still hope it is possible.

Woody
 

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If you wanted more displacement, I would think you might just want to get an H22. Does the CRVTEC suffer from any of the downsides of the H22 as far as handling is concerned? I assume a bit, but probably not that much.
 

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it's a cheaper swap to go with the B20. No weight penalties. No special Hasport mount conversion. No relocating the AC or PS. No driveshaft swapping. You can still use any Bseries tranny/FD, head, cams, ECU with it...you're not stuck with only the H22/H23 parts like in an H22 swap.

if you want a higher rod ratio, then it sort of defeats the purpose of the B20: a B20 swap is done because it's a cheap way to get more displacement. The whole reason to get the B20 is the fact that it already comes with an 84mm bore and all you have to do is hone and add 84 mm bore high compression pistons with a VTEC head. No boring out. No rod changes. Cheap, cheap (as far as swaps go).

Now if you want to go 87mm and fart around with the rod ratio:

You can do all this to the B18...bore & resleeve it to 87mm and if it's a B18C, you're good to go with a 1.58 rod ratio. If it's a B18A/B , bore & resleeve to 87 mm and then you can leave the crank as is, or swap in a B17a crank, or add deck height and use a custom aftermarket off the shelf rod. Bling , bling.
 

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Discussion Starter #7
I see. I wasn't aware that you could bore the b18 that far. I thought 85mm was the limit. But now that I think about it, I guess 85mm was it if you didn't resleve. I forgot about that.
 

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The limit for boring without resleeving on a stock b18b is 82 mm. Some people dare to go as far as 82.5 mm bore without resleeving to stronger iron ductile sleeves. Jarrod Silvers who runs in the 10's all motor for his B18C1 used to have a 1.9L 82 mm bore B18C1 all motor. He resleeved. I figure if he is that conservative with an all out race motor, it would be wise in a street motor as a limit.

The reason why 85mm is a popular bore for B18's is because it gets you into the 2L ballpark. You have to resleeve here though. You can post the stock cylinders for support once you exceed 82mm but I don't recommend running 85mm bore on stock sleeves, even if they are posted for support. Again, it's cheaper, but you are rolling the dice for a bigger potential cost of repair if the piston goes though a thinner wall at high rpms.
 
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