Two different products doing the same thing. Not caring about price, only $50, I'd assume the valve is better than the kit? If so, why? Valve removes fuel return, shim limits it. End goal, 500-550 RWHP without lift pumps or fuelers, etc. Any benefits or downsides to either product? I.e. race valve make the fuel hotter, etc.? Have no idea. Just a though.
I'd assume the 2004.5 to 2006 should fit my 2007 LBZ correct?
Release valve shim kit vs. Race Valve

Release Valve

2004 1/2 through 2006 LLY & LBZ 6.6L Duramax diesel trucks.
Eliminates low fuel pressure rail trouble codes such as 1093 (low fuel pressure during power regiment) and helps maintain requested fuel pressure during full throttle with even the hottest program enhancements. Reduces amount of fuel release back to tank for increased performance.
Simple to install. Race Valve

2004 1/2 through 2006 LLY & LBZ Duramax diesel trucks.
Will not allow any fuel back to gas tank allowing 100% of fuel to be available in extreme performance environments. Eliminates low fuel pressure rail trouble codes such as 1093 (low fuel pressure during power regiment) and helps maintain requested fuel pressure during full throttle with even the hottest program enhancements.
Simple to install.

I Would recommend the shim kit for a everyday driven truck. They will both work on the 06/07's

Also, I dont think you will reach 500-550 rwhp without lift pumps. You dont need dual fuelers, but lift pumps I would think so.

I'm thinking lift also, but will see if codes are thrown first.
Why shim for daily? Whats wrong with the valve? I'm not disagreeing, but just wondering why? I don't know too much yet.

The race valve eliminates the over pressure safety valve, So if something in the fuel system was to fail there is NO safety relief.

The shim kit keeps the factory safety relief valve, just slightly raises the pop off pressure....

You should do the shim valve as you do want the safety feature to still be there in case it is needed. Then you can add lift pumps and you should be near your goal. Don't think you will get to 500 without pumps, going to need that fuel to get there. You are also going to need the transmission to hold it. Might want to consider that when building up as well. Good luck

Why is everything 500 to $700?
Chips, programers, lift pumps, exhaust, etc.
A few mods, OK, but at 5-700 a pop, eek.

You can buy a gasser and put a supercharger on it for $3,500 for a small hp increase.:D

3,500 on the cheap side as well...

I made 450 stock trans with no lift pump just shimmed rail then made 509 on small shoty of nos need to see what shes makin now

The race valve eliminates the over pressure safety valve, So if something in the fuel system was to fail there is NO safety relief.

The shim kit keeps the factory safety relief valve, just slightly raises the pop off pressure....

I was told when I bought the race valve it was the same thing operational wise as the shim kit.:mad: Guess $10 isn't much more now that i've spent the $50. Usually the other way around

Race valve keeps it wide open, shim, does what it says, shims it like .034's open...

Race valve keeps it wide open, shim, does what it says, shims it like .034's open...


This is not correct. The pressure relief valve only opens when the pressure it to high or there is a spike. The shim kit raises the pop of pressure on the relief valve (open's at a higher pressure). The race valve eliminates the pressure valve completly (Full closed). Hope this makes sense...

This is not correct. The pressure relief valve only opens when the pressure it to high or there is a spike. The shim kit raises the pop of pressure on the relief valve (open's at a higher pressure). The race valve eliminates the pressure valve completly (Full closed). Hope this makes sense...


I was backwards, guess you would know!!!!

No problem, Just dont want people to get confused.

So when there is too much fuel preasure in the fuel rail, the valve opens and send the excess fuel back to the tank? With the race valve, there is no return and you can blow injector o-rings Dan? Please correct me if I'm wrong.

I've run both at the strip. I saw no difference in rail pressures(until let off).

Go with the shim kit.

We have seen no problems yet with the race valve, so getting the race valve basically saves you from disassembling and reassembling your factory PRV.

While rare, I have had several calls (mostly diesel shops) where they messed up on shimming. It's not hard, but you must pay attention. If you are taking your truck to a diesel shop that is not familiar with shimming to get the work done, I suggest the race valve or the race fuel rail to eliminate that risk.

There is a little needle in the PRV, and if it falls out, your truck won't run or barely run. There is no need for taking out this needle or the washer that sits on it, but sometimes people screw up.

Only reason I went to the race valve was buddy screwed the facotry valve up iin the vice, race valve worked but ended up having to replace the rail not cheap 375.00 the nick in the valve made a groove inside the rail and it was blowing fuel out the back of the rail on hard runs

Only reason I went to the race valve was buddy screwed the facotry valve up iin the vice, race valve worked but ended up having to replace the rail not cheap 375.00 the nick in the valve made a groove inside the rail and it was blowing fuel out the back of the rail on hard runs
Thats the reason I went with the race valve in the first place. Afraid i'd mess it up in the vise and afraid i wouldn't get it back together tight.

ok, please look at my signatutre, do I need the shim kit, or the PPe Race valve.

Shim kit

ok, please look at my signatutre, do I need the shim kit, or the PPe Race valve.

YES!!! Shim kit...

So I should shim too?

I just shimmed a 05 LLY this week. He is only running a edge box and stock tranny. He stated last night that the truck is running much better since the shim.

DISCLAIMER: Now it may of had a weak prv to start, and most likely should of had it changed under warrentee.

If you are running any performance upgrades on the 04.5-05 LLY engine I would shim it.....

a friend of mine had a shim kit installed earlier this week. The shop only installed two of the three washers. Is this normal or do I need to use all three?

Just two unless you need the third shim.

Just two unless you need the third shim.
What would be the deciding factor ? Try two and if I still get a code go with three ? Thanks Dan

What would be the deciding factor ? Try two and if I still get a code go with three ? Thanks Dan


You got it!;)

Thank You again.

No problem!

I take it this does not apply to the LB7?

If not, is there something out there for the LB7?

I take it this does not apply to the LB7?

If not, is there something out there for the LB7?

No sir...All you need is a good lift pump...