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This was a post to get input on a complete conversion from P75 to p72.

Read the final post for a list of parts and a picture with highlighted locations for components. This conversion will add all the functionality of a P72 to a P75.

IABs, Knock Sensor, and VTEC are all fully functional with this conversion and it is very simple.

Read Final Post

Read final post

Here is a regular socketed P75-A01.
This was done on an 02D01980-1502 board.

The starting point for this conversion is the removal of components at the following locations.
- C63 (Sometimes in Place)(These first three were in place on my test board)
- R90 (Sometimes in Place)(")
- C71 (Sometimes in Place)(")
- R149
- R148
- R141
- R140
- J4
- J12

After Removing those components I added the following along with the normal components found in any chipping kit.
- IC14 SK5151s
- R142 10k resistor
- R143 51k resistor
- R144 12k resistor
- J10 0 OHM resistor
- Q17 A143 (I used NTE2362)
- Q26 D1423
- R107 220 OHM
- R115 220 OHM
- R116 220 OHM
- D11 Diode 1n4004
- Q34 NEC D1780
- Q37 D1423 (C2785 or C2240 depending on which p75 I am looking at This has been in place on all the P75 boards I have.)
- Knock board from the ECU of your choice installed at FC1

And Finally if you can track one down swap everything into a p72 case. Or come up with your own mounting solution for the knock board. I'm trying to figure out what will work the best as an alternate housing for the knock board for when I don't have a spare P72 case.

Here is the picture of where all the components are located. Forgot to highlight Q34.


I just ordered the rest of the components necessary to complete this conversion on a second board to make sure it carries over consistently from one p75 to the next. I will continue to update as I go along. Hopefully this will be added to the WIKI if it turns out to be universally applicable to p75 ECUs.

why use a knock board? seems to me they are more trouble than they're worth anyway

It was a part of the "complete" conversion. I just had a p72 case and knock board laying around so I thought I would convert the P75 to VTEC in a different way and it works great. I need to post up a picture of my completed ECUs. I just finished the second one today and they both work perfect.

sry, didn't realize how arrogant my last post sounded (headaches suck). Sounds like a cool project

Its just nice because no one in my area buys P75s that are converted to VTEC. But when I say it is fully converted to a P72 they sell as soon as I post them up. Just like when I put a P06 converted to P28.

It is working perfect on the first two I have completed. One is running an H22a4 in a 97 Prelude and everything is working flawlessly the other is in a GSR integra and again everything seems to be in perfect working order. The One in the GSR has the knock board installed and running the Prelude does not have the knock board installed but everything is already in place if they ever decide they want it. Although it is pretty much pointless.