Ive been doing alot of research and ive been preparing myself for an LS-Vtec swap this weekend. Ive read alot of write ups on it, but they all seem to differ a bit; some say that you have to change the water pump to a GSR and some say you dont. Im wondering if you really have to change it or not. The setup will be very basicfor now, stock bottom end with a stock GSR head. Also some write ups go into other things such as the knock sensor. Is it true that if youre throwing a knock sensor code than VTEC wont work? I will be using a p72 for an ECU (obd2). If you do actually have to add the knock sensor onto the block whats the easiest way of doing it or most reliable way?? Any input on this is appreciated

 

I don't think u have to change the water pump over but you will have to use the knock sensor due to the fact that you will throw a code with that ECU running the vtec.

Easiest way to do it is to remove one of the bolts from the alternator bracket & thread the hole into the motor for the knock sensor, you may have to extend the wires ( i recommend that u sodder them & do it properly if u have to extend them).

Hope this helps ya out.

Good luck!

 

Here's my understanding on the water pumps. They are geared differently to accomadate the different rpm limits of the engines. An LS will not go beyond 7000 rpm, at least not in normal operation it's going to survive, so the water pump is geared to work most efficently in that range. A VTEC water pump can see speeds in excess of 8000 rpm and must be slowed down compared to an LS pump to work efficently. If you overspin the pump, it will cavitate or churn rather than pump coolant. A change in the diameter of the gear on the water pump also requires a different length timing belt. The tensioner might have enough range of motion to work with either but from what I've read, use the timing belt that goes with your water pump.

I don't imagine having an LS pump and VTEC rev's would be a huge problem unless you spend a lot of time in the upper rpm band but if I was building the engine (and I've never build an LS/VTEC so I can't comment from experience, just research) I would go with a GS-R water pump and timing belt. Knock sensor I can say is nessicary or you will have a code. I've read about tappign the alternator bracket and I think the knock sensor hard spot on the block is even present in some LS blocks, just not drilled and tapped.

 

If I remember correctly the LS and GSR have a different count of teeth on the water pump gear. Im using a GSR oil pump, water pump and timing belt. You can put in the knock sensor but I dont think its neccesary. If you choose hondata it will eliminate it. You could also just have your ecu reprog. to not look for a knock sensor.

 

http://www.honda-tech.com/zerothread?id=1118097

good thread for you. shows where to put knock sensor on the third page