If I install a lift pump, do I still need the shim mod in an LLY?

I'm looking at a 500hp or so tune, stock turbo.

Thanks,

Bud

In most cases i would say no, but it's a good idea if you plan to push the LLY. Realistically, 500RWHP is a stretch with the stock turbo, but mid 400's is a reasonable expectation.

I should add that it is my belief that if you fix the supply issue first, there is less chance of needing to shim. Most of the higher HP units that I do, we shim to eliminate the potential for issues.

Shim it! My truck wouldnt hold rail pressure with a 125hp edge tune.

I now have the 350hp PPE as you well know and with two shims I am now experiencing issues at high speeds and sled pulling(when the truck is under extreme fuel demand) with the relief "popping" and getting a 1093 code. Normal circumstances things are fine. I plan to put the third shim in soon to hopefully eliminate the problem.

Maybe do the race valve, ported fittings etc while you are at it. I mean that's what all the big power guys are doing :rolleyes: I guess I just keep missing the boat...

Add a lift pump, you know you need it anyway. Then see if you need to shim it. JMO.

I the back of my mind, I was hoping that the lift pump alone would solve the need for the shim, but I see from the posts here that I might as well do both.

Thanks for the guidance.

Shim kits are cheap I have one in my glove compartment. I installed my lift pump a couple of weeks ago and my problems are gone. I'm not installing my shim kit unless I start having problems again.

Fix the supply problem, eliminate the pressure cycling and there is far less chance that you'll need to mess with the valve.