mxs accuators

Just ran overhead on one of our T600's and 05 with an MXS in it. Had acuator faults low voltage and non operational on 2 and 5. number 4 already got a new plug. Put new plugs on 2 and 5.

As long as I was in there I ran the overhead. Set intake to .015 and exhaust and brake to .030. Set intake valve acuators to .035 instead of .020. We have been keeping a close eyes on fuel economy so will post how she runs. Will wait a few weeks to post mpg numbers..see if it makes a difference. We normally run pretty close to grossed out so we'll see. Will keep you posted on what the driver says. Hopefully no codes. Also reattached the wastegate tube for the turbo. Previous mech plugged it. I will probably get fussed at as it doesn't build the boost it had...but its stock and was a waste anyways. Probably would've eventually had trouble because of it.

 

Most people don't understand the function of the wastegate on a compound twin turbo system. The high pressure turbo with the wastegate is designed to produce boost at low engine RPM and boost conditions. s boost and engine RPM rises the low pressure turbo come on line to produce the air flow needed. The wastegate allows exhaust energy to bypass the turbine wheel in the high pressure turbo to turn the low pressure turbo. This lowers exhaust gas pressure in the exhaust manifold at the same time it controls boost levels in the intake manifold, by slowing down the high pressure turbo. This lowers the compounding effects.

By lowering the exhaust gas back pressure in the exhaust manifold, you gain free Hp. The engine doesn't have to work as hard to push the exhaust gases out of the cylinder and through both turbochargers when the wastegate is open on the high pressure turbocharger to allow a percentage of the exhaust gases to bypass it.

I've actually seen an engine with a custom twin compound system gain 120 Hp by changing from a non wastegated exhaust housing to a wastegated exhaust housing with a larger A/R ratio. The wastegate was set to open at 22 psi of boost coming off the high pressure turbo. By this boost level the low pressure turbo was supplying the air to support the combustion of the fuel being injected properly.

 

Thanks Mr. Haney...will explain that to the driver. Thats the best explaination I've ever heard of the use of the wastegate on the compound system. Makes perfect sense the way you explained it. Does away with turbo lag and gives you turbo umph low where you wouldn't normally get it.

Can I use the record feature in ET to map what the two are doing and make sure the wastegate is working properly. Make sure there isn't a hole between the two? Hard to watch it that close yourself...thought I might record and graph...can you see where the meet and blend?

What should we see as max boost on the stock mxs?? 40psi? or closer to 35? We hit 35 last night after the work unloaded and on a wet road. I didn't drive it, my boss did. Thats why I'd like to map it. Can you adjust the wastegate to open quicker and feed the lower psi turbo if conditions allow? Or is this something controlled completely by the ECM and would need to be flashed?

I know we talked a while back about our trucks...trying to work my way through them so we can start sending you some ECM's hopefully. Going to take a while to get a good baseline and get everything back straight.

 

Backed mine off to .60 a month ago.Truck runs better and got a few 10th mpg gain.

 

nice glad to hear it.