Title explains it all!!!??

How and what does it do????

 

All these views and no replies???????

 

I poked around, I have not heard of it... what are you referencing, and what application does it pertain to?

 

I have read about this on the cumminsforums but could not find what it does or how to do it. It was on a 6.7 though. It is in reference to the HSperformance kit where the person dyno'd 85 ft pounds of tq with the delete kit and fuel shim release only.

So, im trying to find out exactly what this shim release is and what it does and why some people are doing this mod.

S

 

I do believe you shim out the fuel rail pressure release valve. I cannot see how it would help a stock truck, so I'll call BS on the guy that claims 85 ft-lbs increase by shimming the valve (unless his engine was not right). It essentially reaises the fuel rail pressure at which the pop off valve opens and dumps the pressure in the rail back to the fuel filter. If the thing opens, you will not be making power at all. A stock truck should not get close to the pressure required to pop the valve

If you were mod'ed for more fuel pressure and having problems with the valve opening, you could shim it out to keep it from opening.

 

Sorry if i wasnt more specific, HSPerformance sells exhaust kits that im about to purchase that gives 10 hp and 85 tq, and the truck they dyno'd it on only had the exhaust and the mod fuel shim release. Obviously its the exhaust that gave it the power but im still trying to find out why/what the fuel shim does and why you would do it. But your explanation helps out a little

 

Here it goes. The way it works is you pull the valve out of your fuel rail next to the intake tube. Its job is to return fuel to the pump. You take the valve apart and it has a spring and a pin. When fuel pressure is high enough it opens the valve returning the fuel. If you shim most is .60" it makes it so it has to have more pressure to open the valve thus with fuel mods it will increase the pressure about 2000 psi so the fuel gets put in the engine and not returned with high pressure. With a stock truck it wont be able to go high enough to matter with a pressure box it will. The mp8 comes with the shim kit. Dmax is set up this way and they have done it for a couple years. It is a really easy thing to do. Have any more questions about it let me know. I have done it a bunch of times and it works good on dmax but dodge doesnt have a low rail pressure problem so hard ro say if it works good or not.

 

Also they make a race valve which has no bypass on it so you will get umlimited pressure but take the risk of cracking an injector with too much pressure

 

Thanks KMK as you have always been a good guinie pig for the 6.7.

If you know anything about the f650, please check out the towing thread

 

ccoop769: You can call TS Performance, at (270)-746-9999 and order the Fuel Rail Valve Shim kit by itself over the phone for $10. I did that and had them email me the install instructions for the MP-8 which includes the instructions for the fuel rail valve shim kit. HERE is a link to the Installation Instructions for the MP-8.

 

Is the stock 6.7 rail pressure that close to the limit for the relief valve?

MikeyB

 

Doubt it never seen a problem with low rail pressure on the 6.7. and I think its something around 26000 and shims put it to 28000 give or take a thousand havent seen a rail pressure guage or anything for the 6.7 so not sure what it runs.

 

A stock 6.7 will go up to 27kpsi

Bob

 

DO you have to use the mp-8 module along with this shim mod or can you just run the shim kit

 

You do not have to run a pressure box to do the mod but there is no need for the mod without added pressure (edge ez / MP-8 /etc)