B20A5 knock sensor location/install - Honda Forum / Acura Forum

uoboarder · 06-27-2002, 07:18 PM

I've got a B20A5 block that doesn't have a knock sensor. The location of the knock sensor is where the oil sending unit is. I was wondering if anyone knows how/where to install a knock sensor onto a 89 B20A5 block. Does anyone know of any tech websites that could help with this problem?

I need the knock sensor for my B20/VTEC swap. What ecu do you who know recommend? Or should I reburn a ecu?

jdmsijdm · 06-27-2002, 09:17 PM

can you use that block? isnt that a prelude block? i thought it was a completely different design then the crv b20 blocks. Im probably wrong but i though i heard that before.

uoboarder · 06-28-2002, 01:19 AM

yeah, its a 89 prelude block. you can use it to do a B20/VTEC swap. I've heard that the stroke length is different on the B20A5 block from the B20B/Z blocks and that since the stoke is shorter it makes torque curve different. I know it'll fit, but how will it function with the knock sensor machined in another spot. Can that even work? I would like to make the B20A5 block work cause it was given to me for free.

Dennisman · 06-28-2002, 03:40 AM

B20A (Older Prelude Si)
Rod length: 141.7-142.75 mm
Stroke: 95 mm
R/S: 1.49-1.50:1
Displacement: 1958 - 2056 cc

This works out to an 81 or 83mm bore size.
Ive heard they werent very good engines and looking at the poor rod stroke ratio, seems that trying to get high RPM power from them might not be wise.

v4lu3s · 06-28-2002, 08:12 PM

i have heard of a vtec head being swapped onto the b20a5...but it was for a 3rd gen lude. http://ludicrous2_0.tripod.com/vtec/ has a lot of info on it...and it doesnt seem like a very good plan...

uoboarder · 06-28-2002, 08:58 PM

thanks for the help. that site was very helpful. I kind of wonder how the project turned out. The B20A5 block I was going to use was free so I just wanted to see if I could make it work.

The installation and machining of a knock sensor still troubles me.

skidtron89 · 07-01-2002, 04:25 PM

Quote:

Originally posted by uoboarder
thanks for the help. that site was very helpful. I kind of wonder how the project turned out. The B20A5 block I was going to use was free so I just wanted to see if I could make it work.

The installation and machining of a knock sensor still troubles me.

Why not use a B16A head and ECU from the EF SIRs in Japan they don't run a knock sensor at all? That would solve your problem except you probably already have the head and ECU form something else........

uoboarder · 07-02-2002, 12:04 AM

that's a good idea, however I was thinking about using an ITR head or porting my B16a2 head and using that. I talked to the shop that's going to help me install it and they recommend that I have the knock sensor since it detects predetonation...something I'll need when I through on a turbo.

I've given some thought lately to just getting the GReddy turbo kit for the B16a2.

skidtron89 · 07-02-2002, 10:09 AM

No just use the first gen B16A head and ECU and then Greddy turbo kit. Why the first gen B16A head and ECU because I said so and because it came from the best gen of Civic the 4th gen. I was just kidding about the because I said so but the rest is true......