So is a little what you are doing or are you saying less than an inch? I will go with APS also.

So what about buying a kegger from a 1998 or newer truck...will that work for me? Will I still have to cut down the runners?

Brad

 

I'll attempt to explain and if I'm wrong anywhere somebody holler and I'll fix it, or mods please feel free to edit directly. This forumis kind of like Wikipedia for Trucks: lots of info but you gotta make sure the source is credible.

I'm too sick to work and bored off my gourd sitting around, so you'll get the lengthy explanation Brad.

What Silver_Dodge is doing is opening up the runners on the inside oftheintake manifold. Think of your engine as a big air pump. Opening up the restrictions on any part of the engine makes it breathe better and can produce more horsepower, torque, both.Each time youadd a mod like abigger exhaust, bigger air filter,larger TB, cut runners, add roller rockers, etc., those mods all worktogetherto produce more power. It's like breathing thru a coffee straw andthen upgrading to aMcDonald'sstraw. It gets easier to breathe.

Example: Opening up the exhaust by installing a single 3" pipe with a high flow cat andhigh flowmuffler can increase horsepower and torque. You can further increase that bygoing witha bigger air hat, increasing TB (throttle body) size, cutting the runners, porting the heads, intalling largerheaders, etc. to put more airthru the engine.Each time you mod, a new part of the engine becomes the biggest restriction andaltering that nets you the biggest increase, until you ultimately loop back around to that oldest mod that needs to be improved. Likeif your engine can produce over 350HP you might want to go with a bigger than 3" exhaust, then a bigger air intake, TB,and so on, until you've maxed out what your block, tranny, or whatevercan handle.

Silver's debating what the optimun cut is on the runners to open them upto match his current setup.At stock, the runners are probably fine. Silver's done some extensive mods and can now benefit from opening them up to get more air into the firing chamber. If he doesn't cut them enough, he won't receive maximum benefit, but there's also a possiblity that if he cuts too much, the only gains he'll really see are at the top end of his RPM's when his engine's really sucking down the air, and his lower end power will suffer a little for the towing he does. Understand thatpiston firingis all happeningwithina very small frameof time, so things like air velocity versus volume of air are kind of playing against each other here. At WOT (wide open throttle),air volumeisusually a limiting factor, and the velocity is based on how quickly the engine can suck it and fuel down, so you'd want as open a keg as you could get, but at lower throttle a balance should be maintained, which is why the blades on the TB move back and forthas you push and release the gas pedal.

Older intakes had a divider down the center probablyto balance out theEGR gases. The newer models don't have an EGR unit and so don't have the center plate. The center plate could be an air restriction as the cylinders all fire in a criss-cross pattern and the plate exposes the firing cylinder to only one open barrel on each side of the TB (well, the air has to travel under and around the plate, too long if you're really flooring it.) Cutting out the center plate exposeseach cylinder to both TB ports and nets more air into the firing cylinder.

Regardless of center plate or not, you would still need to cut down the runners. Cutting down therunners allows each cylinder to take in more air, so the net is more air flow at a lower throttle. You haven't increased the speed of the cylinder firing so the net is more power at lower engine speed.

 

Haha,it took me so long to type that y'all had moved on!

 

I think maybe you got it backwards after typing for so long.lol- At wot, air volume (runner volume anyway)is a big problem with the stock intake manifold. That's why stockshifts are setat a paultry 4800 rpms. People say the M1 kills low end torque (alot of people are those who have never seen one outside the internet). One reasonis that at part throttle the runner volume is greater than the amount of air that the tb is letting in, and, therefore, the cylinder charge loses velocity. This may be true from idle up to 1500 rpms, but, after that, the engine is sucking so hard through the short runners that there isn't enough distance/time for the air to 'slow down' and since the stock tc (supposedly) stalls at 1800 rpms you aren't there very long anyway. Second reason people may experience a torque loss is because injectorpulsewidth on the stock pcm's tunedoesn't go high enough to compensate for the added air soyou run lean.

Silver_Dodge,
I am interested in your project. Please keep us updated. It will be especially interesting if you cut more or less than steve05ram360 so you guys can compare where the performance gains kick in.

 

hehe, I wrote that confusingly, blame the Nyquil.Fixed it, let me know if it makes more sense,

That's a nifty tidbit about the PCM when running the M1. I'm assuming this is corrected on the B&G flash and is the main staple of the M1mod they list after several flashes.

 

Unfortuantly, there was a lot of differences between my truck and Steve's. His was a 360, mine a 318 for example. So not sure if it will be a good comparison or not.

 

Mopower, mine just kept on reving well up to 5k (which is where I always stop if I ever went that high). On the M1 & injectors... you make a great point there and your the 1st person in any thread I've read on them that mentions them running lean, that makes total sense. Also makes sense as to why everyone always recommends the custom flash to go along with the M1.

speaking of which, Ried, did you get the intake mod considered when doing your custom flash? your motor should easily rev past 3500 now...

 

Yes I did. When I called B&G, I told him that I was interested in the M1 flash, but was considering doing a modded kegger instead of the M1 intake. So they set me up with the M1, but adjusted the shift points to still work within the range of a modded kegger. Little higher then I like for the stock kegger, but it should work well once I get the mod done.

 

M1 flash is all about shift points, fuel, and the timing to go with it. I forgot what the exact ms value that the stock flash went up to, but it was suprisingly low. I want to say 14ms???. LT trims go from -10 to -low 20's with the flash. Stock timing at wot goes to 25* advanced at wot, M1 flash goes to 30*. Cruising above 2000 goes from 30* to almost 40*. It also bumps the idle targeta bit to compensate for reduced vacuum signalat 650 rpms.


Missed that. It would still be good to have results and the actual cutting done posted everytime someone did this mod. I talked to Hughes about this (Iran a Hughes stage 2 keg for 2 or 3 days before selling it on ebay) and it sounded to me like they didn't really do any extensive testing. I think they arbitrarily came up with 12" and 14" final runner lengths, called them stage 1 and stage 2, and got them up for sale. I got sucked in by the filling part of the advertised "ported, milled, and filled". They did do a nice port job, but, as examined with a mirror (couldn't see everywhere), the filling was epoxy gobbed along the top of he manifold in a few different spots.

 

Here's an interesting read. Came out of the July '97 issue of Mopar Muscle - Inductive Reasoning.

Excerpt: "Most dry OEM manifolds have large plenums to supply the cylinders with enough air and long runners to generate torque. This combination of long runners and big plenums is great for gas mileage and bottom end power, but does not lend itself to performance. Even though the OE Magnum manifold falls in this category, it's easily modified and shows substantial horsepower improvements when worked on. One inexpensive revision that aids upstream air density is the fabrication of a lifter valley heat shield. Magnum manifolds have a flat steel cover bolted to the underside machined surface. It sits just above the lifters. The plate becomes absolutely torrid when the engine is up to operating temperature. NHRA truck class racers bend up a piece of steel plate the length of the manifold cover and weld it into place. This shield acts as a heat buffer by isolating hot splattering oil and rising heat away from the manifold's bottom cover plate. Because the factory cover is not getting direct exposure with the shield in place, air in the manifold stays cooler (denser). Cash outlay should run under 25 bucks at your local welding shop (plus new gaskets). All you need is a flat piece of steel stock, 1/16-inch thick, bent at the ends, and welded into place. Have the shield welded 1/2 to 9/16 of an inch off the valley cover and you're all set for the dance. Though it won't up your HP figures, it will allow you to run more consistent times on hot summer days. This mod also helps prevent pre-ignition in street trucks that see engine temps soar when hauling heavy loads. While your V6/8 Magnum minifold is off, the next performance step is to shorten the runners as much as possible and cut two inches out of the plenum divider. This mod will add about 10/12 HP to your engine and raise your shift points about 300RPM. OE castings are made from some pretty tough aluminum, and buzzing away with a grinder can get tedious. A better way to go would be to have a machine shop mill the runners flush to the castings port floors, then get in there with your grinder to clean things up. Finish touch the runner mouths with a polished radiuses so turbulence is minimal. None of these grind/olish/weld V6/8/10 modifications require a high performance computer because factory computers require a great deal of latitude to cover everything between lean high altitudes to rich seaboard environments. Lastly, there are two Magnum precautionary notes. It's common for Magnums to blow the gasket that seals the cover to the manifold. You'll know when that happens because the performance will slip off par, or you may begin hearing pre-ignition knocks. Lift your hood, remove the air breather lid and look down the throttle body. If the venturis are dark, sooty, or oily looking, your engine needs a new cover gasket. What the heck, you can modify the intake while it's off. When you finally replace the cover and gasket, be sure to put silicon on the cover side of the gasket and use a fixative on the bolt threads. The other concern centers on the lifters. They're real heavy and overcome the strength of the lifter bore casting at high RPM. Spinning the Magnum to 5400 RPM is borderline, 5800 RPM too much, and above 6000 RPM can be the kiss of death. What happens is the heavy lifters crack the casting, start to wobble, and the valve train self-destructs. When the valve train starts to go bonkers, you'll notice an upper RPM vibration, almost like the engine is out of balance. Either limit your shift points, buy a Fluidampr, or pray somebody develops a lightweight lifter for the Magnum. Magnum plenums are extremely large. By taking up some of the volume, resonating effects (powerful pressure waves) are increased, augmenting low end torque. And, because the Magnum's not a high RPM engine to begin with the high end is not affected. This is an involved process. The high dollar route would be to buy four quarts of Devcon and fill each corner of the intake. Besides being expensive Devcon is heavy. Another approach is to scrounge up some 1/4 inch plates of quality aluminum, make some cut outs from cardboard that, when heliarced in, box up plenum space in the manifold. It's time consuming, but seems to work. Magnum V8's really respond to this plenum reduction plan. Even though the V6 has a smaller plenum to begin with, resonation is much greater than a V8. Nonetheless, power increases with a plenum reduction. The intake manifold is probably the most underestimated piece of performance equipment on the engine today. When modified with even simple changes, it responds unbelievably well. Though some of these alterations can get quite expensive, a bucks-down performance aficionado can still do quite a bit on a Saturday afternoons tie span. Though the new millennia will undoubtedly bring further developments in the intake manifold, on thing's for sure; as long as the internal combustion engine is around, it will always have need of an intake manifold."