Without the need to get extremely technical on me... can anyone out there give me some insight on this cam from MTI out of Houston, TX.

X1 - (duration) intake 230/ exhaust 227 (lift) intake .591/ exhaust .571 lobe seperation 112.

I'm having this package installed by MTI next month and I'm curious as to the overall performance gains from everything.

- MTI Stage II E Cylinder Heads
- MTI Custom X1 Camshaft
- Kook's 1 7/8 Headers with 3 Inch Catted Mid Section
- Xcelerator Custom C6 Air Intake System
- Fast 90MM Intake Manifold
- MTI Underdrive Pulley with New Belts and Crank Bolt
- 7.4 Hardened Pushrods, Bolts, Gaskets, Fluids and Filters
- Professional Installation and Dyno Tuning

Any and all input will be appreciated... thanx in advance

 

This is a "reverse split" grind (intake duration is greater than the exhaust duration". Combined with the 112 LSA, should give you a fantastic mid-range. Should sound totally nasty at idle.

Jury is still out on the reverse splits, but some have had good success with them.

 

If you don't mind me asking... what are the general sentiments in regards to the "reverse split" grinds?

 

imo, dual pattern, dual profile, and reverse splits are better choices than a single pattern.

the 'intake' mass is greater than the 'exhaust' mass.

as long as the exhaust valve is open long enough to completely purge the cylinder and create an intake vacuum that's all you need.

the exhaust does not need the same pattern as the intake due to the different types of gasses between the two side. intake is fuel and air, exhaust is fumes.

 

Most performance shops don't recommend them, with a few exceptions. For example, I have seen posts from a few vendors here (LPE?) with negative opinions.

They work best if you have a good set of LT headers. Because of the increased combustion pressures, preignition and knock retard can be a problem, especially if you are also running a set of milled heads for higher compression.

 

There is no one cam "type" applicable to all engines. It all depends on what type of racing/street use, compression ratio, power adders (nitrous or super/turbocharger), and most importantly, the intake/exhaust flow ratio of the cylinder head (assuming the intake manifold and exhaust system can keep up). A single pattern cam may very well be the best cam for a particular engine.

Without getting into a big chemistry discussion, you can't destroy mass. You can change it's shape, form, or composition, but whatever amount of mass goes into the combustion chamber comes out although under higher temperature and pressure but lower density (for equalized pressures). There is actually more volume to the exhaust stream but that is countered to a certain extent by more pressure to aid it's flow. It's not such a simple cut and dried solution. For example, nitrous and supercharging require more duration on the exhaust side than the same engine without those power adders because the intake side is getting a "boost" in flow so the exhaust side needs a little help to keep up. But if you turbocharge that same engine, you'll want less duration on the exhaust side than the NA engine to keep exhaust velocity up to spin the turbo faster. In other words, you don't want the exhaust valve opened so long that flow goes back towards the cylinder creating a momentary negative velocity which lowers the average velocity thus reducing the energy imparted to the turbine wheel of the turbo...and that reduces boost.

 

HITMAN99 has some pretty good insight here as well as his other post (good midrange and choppy idle). If MTI has done the development work for this cam with their "Stage II" cylinder heads, I would think the cam matches the flow of the head. If you're looking for the midrange with a nasty idle, go with their package. One thing a narrower LSA can do is increase the peak HP number which while good for bragging rights, will usually give less average HP and impact fuel economy more. Also, as HITMAN99 said, static compression becomes more of a concern with narrower LSA cams. The LSA affects the closing point of the intake valve which is the single most important valve timing event of the four (intake opening, intake closing, exhaust opening, and exhaust closing). With a wide LSA (and same duration specs), the intake closing event gets moved later which affects (lowers) the dynamic compression ratio (or pressure ratio), and that is what the engine sees when it's running. With a lower pressure ratio at low RPM, you can run more static compression without detonation and increase efficiency (MPG) at low RPM and power at high RPM. If the cylinder head flow can keep up with the cam, a wide LSA cam has the potential to make more peak HP. Hope this helps a little, basically it boils down to "pick your poison" and chose your tuner.

 

This is some really great information as I don't know much about the internal mechanics of an engine. Keeping it simple, to some extent, has made this easy for me to understand.

With regards to the cam, you mentioned something about an impact of fuel economy. This alone concerns me as I've seen some folks with head/cam packages which have maintained respectable MPG while on the other hand I'm trying not to adversely effect my fuel economy.

Bottom line: will the car suffer tremendously in the fuel consumption department?

 

I doubt much that it will suffer tremendously, but it could drop a bit. A lot depends on your driving style, and your tune.