I have a ls/vtec and the oil pump is a ls. The problem is my vtec is not working. IT will try to change over but you will feel a lag in the car as it hits the vtec range. I checked the vtec oil pressure and it reads 50psi 10 below the normal. Do i need a gsr oil pump and whats the differences between them?

 

the vtec oil pumps and the b20 oil pumps are a bit higher, but it shouldn't make a difference. This happened to a friend of mine. Double check your timing (cam and ignition), and if its not off, take your cat off and drive it around like that, and check to see if you can see through it, if not, smash the internals out (or buy a new one). Its cause when it goes into vtec it gets choked off by the ****ty old cat. At least, thats what happened to my friend....

 

was your friend using the b18 or b20/b18c1 oil pump? I 'll try that and see if it works this weekend. the timing and everything is correct.

 

You need to use a vtec oil pump, the LS doesn't have enough pressure to engage vtec. You can modify the LS pump to flow higher by shimming the spring, but I don't really know how much to shim.

 

What do you mean by shimming the spring ?

 

My vtec works now but i don't real feel any hard pull. It doesn't seem to lag when i hit the vtec range. The problem was my cat was clogging up the exhust gas from flowing through.