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Clash of the Titans - Mamo MSD Airforce vs Mamo Fast102
Ladies and Gentlemen!! Well, mostly just dudes on this site. The fight you have all been waiting for to see which stock-style intake is king of the LS1 5.7L cathedral port engine.
The fight was held on a neutral playing field, allowing an equal number of fans from both corners to watch, leaving no homefield advantage. The test bed is set as a 346 SBE LS1 with Mamo 220 heads, LLSR cam (237/245-112.5+2 232/240 hydraulic equivalent), dual 3 exhaust and 1-7/8 headers, and as much drag removed from the engine and drivetrain as feasible. There are two parts to this fight. Round 1 will be tuning and street driving. Round 2 will be dyno overlay. All measurements in rear wheel numbers. Lets get ready to rumblllllllllllllllllllllllllllllllle!
In one corner, we have the Mamo Ported Fast 102, known now for quite some time as the king of the hill, top dog intake for the LS1. Its been the standard by which all other LS1 intakes are measured boasting good midrange torque AND good top end airflow to support carrying power past peak. This champion has been challenged in the LS7 league. Can it retain its title in the cathedral port league?
30. FAST 102 LSXR. This thing is gorgeous in person, if you've never seen one.
32. Mamofication effect
In the other corner, we have the up and coming hot shot rookie from MSD, also ported by Tony Mamo. This upcoming star has been making a name for itself in the square port LS7 arena, beating the fast102 at top end power and carrying past the peak. Leaving many to wonder what would it do on a 5.7?
Early betting favors the fast showing higher torque at lower RPM to the tune of 10-20 lbs. Ringside analysis of the fast is showing that the longer runners are known for delivering good torque while still flowing well at the top end. The fast is known to support big power from bigger motors, so the plenum volume and total flow of the intake are expected to be non-factors. The runner length is the X-factor here. Numbers from LS7 configurations are figuring heavily in this analysis.
The line on peak HP is leaning to the MSD for a higher peak HP at a higher RPM. Total flow and plenum volume again are not expected to be of much influence, but the runner length vs the intake valve close timing vs the RPM of the motor are expected to continue to favor the MSD as the RPM increases. As with torque, oddsmakers are relying heavily on the LS7 data between these two champions.
Driving the Fast102 on this combination is not bad. Idle tuning was typical for a fast102 with a 102 throttle body time consuming and tricky. The main issue was that the car would always try to trim rich no matter what you did unless you left it in open loop. Lots of guys have seen this. To get it to quit, I set the O2 sensor switchpoints at idle to 150mV and turned off the idle proportional fueling AND used lower error multipliers than stock. Now, with a catless dual exhaust and an 11 degree overlap cam, I never got rid of the NOx or fuel smells at idle, but I was never going to either. With the MAF enabled, it was easier, but SD was always trying and took many successive minor tuning tweaks to get right. Especially the return to idle stuff. It seemed I either lived with a hanging idle or a stumbling idle until I finally found that happy medium. Im sure a lot of this was my learning curve too.
The one thing I was never able to resolve was this hole in the tune around 2500-3200 rpm. The car sort of just sounded like it was breaking up a bit in that range. Now to be fair, it never did it on the old 227/235-112+3 hydraulic cam, but I was never able to resolve it on the fast102 and LLSR cam combination. Neither timing nor fueling would fix it, and it was the same in MAF or SD.
Not to get too far into it, but the IVC on the old cam was 42.5 ABDC. The IVC on the current cam is 46.5 ABDC warm with 0.007 lash. Cold, its actually 49 ABDC. You will actually be able to see this hole in the torque curve in round 3. On the sheet, its 2000-2800 rpm, but on the street I feel it and hear it from 2500-3200. In retrospect, I now wonder if there is a certain harmonic between cam events and intake runner size that one is better for the other and vice versa. Everything else works like a system why not these two variables, right?
All this said, I was basically able to hook up with 275/60/15 mickeys on the street on the fast102 on this current build with everything thrown in. Of course, I could dump the clutch and spin the tires, but hooking from a roll was effective. In the end, this intake made a very fun, fast, and streetable combination as long as the owner is willing to put in the work.
Driving the MSD is actually pretty good. I wasnt sure what to expect, but I was pleasantly surprised. Off idle (up to about 1500 rpm) torque feels a bit worse on the MSD vs the FAST.
Idle tuning was surprisingly difficult. There were quite a few things I had to forget. Very first thing to happen is once the car started and warmed up enough, it immediately went to -30% fuel trims at idle. So, I smoke tested, and no leaks - and I had no leaks on the fast either according to smoke testing. I also saw that at idle, dynamic air was moving around quite a lot more on MSD vs the fast. And it idled at 70 kpa vs 60-65. What I had to do was compress the VE table from 0 to 75 kpa in the 0-1200 regions to get the airflow calculations to read a steadier number. Important, because the fueling calculations smoothed out, which helped stabilize quite a lot. And I put the O2 switchpoints back at 450 at idle. It needed a lot more commanded air as well. I think that the shorter runners do not develop as much momentum for the air, so the cylinder fill at idle is greatly reduced.
Then, the return to idle PITA started. Wanted to stall out at every stop, etc, stumbling and hunting, same crap a lot of cammed cars do. I ended up having to be absurd on the amount of follower air I added to get rid of the stumble which of course hung badly, but now I have begun slowly backing off on the follower air. Right now, Id say the amount of follower air is only half absurd. And it needs the follower and cracker to stay active until the moment it stops. Ive only had it on the car since the day after Christmas, and I think in the coming weeks I can get it back to where I had it on the fast where it would hang at 1200 rpm and then drop to 950 around 10-mph and idle smooth. I miss that.
Now, on the plus side that hole in the RPM is gone. It accelerates smoothly from 1500 to redline. With that hole gone, it made the engine feel torquier, even though that goes against the expectations based on the runners. Pretty much every expectation is that the fast will have more torque at lower RPM. The seat of the pants experience is saying that the MSD feels torquier through the midrange as well as into the high end.
The same 275/60/15 mickeys that hooked just fine on December 23 still hook, but its even more sensitive to clutch dump. My first four attempts to feel the power, the car went sideways. If there is any evidence that the car gained power, it is that the tires are slipping near redline. Being fair, they might have already been on the edge and just that little bit more was all that was needed, but it caught me off guard and took four attempts to get it to take off in anything resembling a straight line.
Round 1 Decision - I score this round MSD 8, FAST 7
Its close, but in the end, I think I have to decide in favor of the MSD over the fast102. Im not really sure if it is the intake or the combination of the intake with my cam, but the smoother application of torque as felt while driving it really makes me lean toward the MSD ON THIS MOTOR. Even though the tuning pain was higher, I feel that tuning the car is temporary vs the enjoyment driving it, and living with a problem that couldnt be tuned out vs a harder to tune problem that CAN be tuned out, the choice is rather clear. Neither gets a ten, because there was no clear-cut victor. Nobody got knocked down. If it were not for the idle tuning difficulty, Id feel more strongly about the MSD as a clear cut winner on the street. Did I mention idle tuning was a challenge on the MSD?
Post Round 1 analysis In the past, I had thought that hole in the rpm band was something tune related and that I simply lacked the skill or knowledge to fix it. But after simply not being able to fix it with fuel or timing, I now realize it was a feature of the motor configuration. I have long assumed that the hole was strictly related to the cam. After all, this cam is set up for revving, not towing. However, the shorter runner of the MSD intake appears to have eliminated the hole that simply could not be tuned out. It may still dip down, but it doesn't sputter and break up the way the fast did. Unless something else happens to disprove my theory, I think that the optimum total length of the intake runner and head runner are significantly impacted by the intake valve close event timing with an earlier IVC favoring a longer runner and a later IVC favoring a shorter runner at any given RPM.
So, the first thing to jump out at me is the differences in the torque curves. Notice how the fast is almost "wavy", where the MSD is much smoother and broader vs the fast. This actually explains the differences I felt driving around. The behavior is almost like two different cams - one with a narrower LSA and one with a wider LSA, but both with similar durations.
The other obvious feature is the change in the HP peaks and breadths. The MSD pulled higher and longer, which was exactly as expected at the top end. Note that the curves crossed at 6400-6500 rpm. In the LS7 tests, the curves crossed at 6000. So, which is better? Which intake should be crowned?
Before writing the conclusion, note that the torque curve was not nearly so wavy on the old cam. This points to an interaction between the intake runners and the cam timing that is very important to note. For now, i'll leave you to digest the curves and I'll write the conclusion tomorrow.
Note that the FAST curve did not look like that on my old cam.
The MSD is a better match with the LLSR in every test I've seen. Being able to pull past 7K and still have something in the tank will make the LLSR/MSD combo faster at the track with proper gearing/tire.
On the street with a hydraulic the FAST is probably a better choice for midrange torque. Neither is off a whole lot from each other... but having another 500 RPM will win a race.
And return to idle pain... ugh. My VE table is still not playing nice around idle. I am MAF only right now... and it drives like stock.
The other obvious feature is the change in the HP peaks and breadths. The MSD pulled higher and longer, which was exactly as expected at the top end. Note that the curves crossed at 6400-6500 rpm. In the LS7 tests, the curves crossed at 6000. So, which is better? Which intake should be crowned?
Darth
Was good to be back at it (again!) working with you on this awesome attention to detail build!!
The results you have achieved are clearly the combined efforts of hard work, dedication to see it through, and naturally selecting the best components for the job, but the point I'm making is you need all three to land where you did....for the guys watching from the sidelines, know it takes commitment to duplicate the same.
That said I want to clear up a comment you typed that I boldfaced/highlighted above as it could cause confusion. The LS7 MSD ported (vs the FAST LS7 ported) is a landslide victory for the MSD....it beats up the FAST everywhere....low....middle...high.....there is no "crossover" at all...MSD is stronger everywhere and to the tune of 20 RWHP or more at higher revs!! The ported LS7 MSD is the (yesteryear) Mike Tyson in that comparison. I think you meant to compare this test to the test I conducted on the engine dyno some time ago with the 416 CID cathedral headed engine....the curves are very similar to yours (no coincidence) but the larger engine and the larger air demand make the move to go with the MSD a little more logical as it happens sooner and you have the extra torque to give up with a stroker....swapping that out for some gains in HP and the ability of the engine to hang on to it a good bit longer makes alot of sense.
This is the test Im referring to and what (I think) you were also alluding to above but for some reason you mentioned LS7. This comparo below is a 416 HR engine I built and the same day on an engine dyno swapped from a ported FAST I did to a ported MSD....both cathedral port intakes naturally feeding my MMS 235 heads. The bigger engine gives up less TQ and rewards you with even higher gains in power because it has a much larger appetite for air.....all of this is very logical
Im glad the MSD worked out exactly as we hoped (Jacob...aka Darth....and I were hoping to see around 10 RWHP up top from the swap and expected to give up some torque in the middle to get there). Bottom line is the MSD acts like a shorter straighter runner which is no surprise.....its exactly that after some major surgery with the grinder....speaking of that I should comment on the fact it requires a heap of work to get there. In out of the box trim the FAST would have walked the MSD everywhere....its a much better piece out of the box (the FAST). The MSD has potential (clearly) but of ALL the plastic/composite intakes I have ever ported, the cathedral MSD requires the most material removal to get it in "fighting shape".....continuing the theme of this thread of course.
This is how much material I remove from an LS7 MSD intake (which is 2nd place in the "material removal" department).....but seriously.....the MSD cathedral would fill the bag by another third or more of what you see here. I would wager I remove close to half a pound of plastic from a cathedral MSD. The cross sectional area of that manifold is really small in some areas of the intake ports and I have to get aggressive on all eight ports to get the port taper correct from the bellmouth to the exit.
This thread should probably be in dyno results section also....I think it would get more people looking at it and I feel quite a few folks would be interested in these results as its a very interesting comparison and it ties in to the recent move to more folks considering an SR cam.
Awesome write up Darth and thanks for sharing! I love the smoothness of that MSD graph. The only thing that would be my complaint with the MSD is from 5250 to 6250. BUT, I know your main goal was to extend the RPMs and gain at the peak hp. You did both!
After really thinking this through, I think I prefer the MSD, but it's almost a draw. It really depends on how you plan to set up your motor and use it. So, here is some comparative numbers peak to peak:
Now, the rest of this is hard to put into a chart or analyze like a score board, but here are some things working for and against each intake:
FAST - there are a few spots right in the meat of the power curve where the fast has 25 hp advantage over the MSD. And even though the torque curve is "wavy", it is making more torque on those peaks. it's odd that the car felt the opposite of the dyno graph in this regard. Had it not been for that last torque peak, the fast was looking like it would peak at 5100, which is where it peaked on the old cam. In that sense the 6500 would have been about right. Now, there is something else - on the dyno video, you could hear the motor just flatten out. It was an odd tone change almost like hitting a wall. At first, I thought this was the motor outrunning the intake, but now I think that is not technically correct. It is more like the motor was trying to outflow the intake runners. It's a fine distinction, but try this - breathe through a straw, cut the straw in half and repeat. It takes less effort to get the air started in each direction, which you can feel in your chest. I think it just reached a point where the air could no longer develop the momentum as rpm increased - particularly over about 6800. Keep in mind, this was not the case ont he older cam. I'll get into this a bit later. The old cam had peak hp at 6800 rpm on the fast intake and a smooth torque curve, not a wavy one.
MSD - HP peaked higher, at a higher RPM and carried out further past peak, which was exactly as expected. What surprised me most was this 25 hp gap between 5500 and 6000 rpm. I expected the torque to be down a tad, but the torque curve was actually broader. Note that it stayed over 375 an additional 400 rpm vs the fast, which was interesting. In this sense, to me the intakes behaved almost like two slightly different cams than two different intakes. If you follow this cam comparison, the MSD acts like it has a bit less overlap and a bit wider LSA, which smooths out the curve, and also broadens it. The MSD curve looks similar to the old cam on the fast intake - although the old cam peaked lower and didn't carry as far
I score this round a tie: 9 each, but with a caveat, which I'll go into next post
A real world test would be taking a car to the track running it with the fast 102 intake then swap the intake for a msd unit and then compare the mph/e.t times.
Footnote.... I've seen a fbody with a 427 stroker using a ported fast trap over 140 in the quarter all motor. I'm still waiting for the msd to do so.....
In a split decision, I'm going to have to declare the MSD the winner. Just like Rocky, though, each side's fans could easily claim they would have won with an added round or two.
The better intake can only be determined by how you set your motor up and how you plan to use it. It's not like the fast102 vs the ls1 stock intake. These are both very capable intakes with very different strengths and weaknesses, so how you plan your build and how you plan to drive are critical to determining the better intake for your car
RPM considerations - Do you like to rev to 7500 or do you pucker up at 6700? If you plan to rev, you probably want the MSD. If you plan to budget build a valve train, and sacrifice the valve train stability, you're better off with the fast, and taking the lower, earlier power peak. High RPM = MSD. Low RPM = FAST
Cam timing considerations - It's about to get deep, but I think there are some real clues here. I'm going to focus in on the intake valve close event. Starting with the factory LS6 cam, LS3 cam, LS2 cam. All use stock runner lengths, rev pretty good, and have smooth torque curves. IVC is 42.5-43 degrees ABDC. These cams have negative overlap (which is actually a misnomer, but we'll stick with it). My old cam? 42.5 degrees ABDC IVC and 7.5 degrees overlap had a very smooth torque curve. Now, in PatG thread for the Recipe to 500, he touches on this and how the IVC can be moved later to cheat the runner length resulting in double hump curves. Any guesses what IVC he considers the breaking point? 43-44 degrees ABDC. My cam is 46.5 degrees fully warm, assuming 0.010" hot lash. Since I preloaded my valves 0.003" cold, my IVC is likely closer to 47.5 degrees, resulting in - not a double hump - but a triple hump torque curve. I have come to the conclusion that the IVC valve event is very important to intake manifold selection. As a general rule, I would say if you're going to have IVC around 44 degrees or lower, the fast is the better intake. If you're going to run a later IVC than 45 degrees, then the shorter runners become beneficial. There are no absolutes, but I think as a general guideline, this will be adequate.
Combination, Combination, Combination
You've probably heard several people say heads and cam go together like peanut butter and jelly. And they do. But the intake is more a part of the sandwich than was previously thought for sure. You want chunky or creamy peanut butter? Grape or strawberry jelly? There really isn't a clear cut winner in this fight, because of the interactions that will benefit one intake or the other depending on how you want to run your build. You really need to study the entire system and pick the part that works best for the entire system.
So, if you're going to build a motor with a cam IVC later than 45 and spin it really hard, then gear it down even more to gain even more actual wheel torque, this is a perfect MSD scenario. Because this is how my motor is built, the MSD works better for me.
Now, look at the majority of the shelf street cams that are out there with IVC in the 41-44 range. These cams perform quite well, and there is no reason not to use them, but understand they are designed to work with stock runner lengths, peak around 6300-6500 rpm and then fall off. I still think the MSD would carry better past peak than the FAST, but this is where you have to be honest with yourself about how you drive.
This brings up shift points. If you are going to shift at 6700 or so, then there is no reason to step up to the MSD. The curves crossed at 6400, so all your advantage is after 6400 on the MSD. The farther you plan to ride that RPM, you start to see an increasing advantage for the MSD. but you have to rev to make up for the power deficit at 5500-6000, so 7000 rpm should be the minimum to take advantage, and I'm honestly thinking 7400.
I hope you found this test to be informative and entertaining. Will now take questions from the press...
Awesome write up Darth and thanks for sharing! I love the smoothness of that MSD graph. The only thing that would be my complaint with the MSD is from 5250 to 6250. BUT, I know your main goal was to extend the RPMs and gain at the peak hp. You did both!
Thanks! The other goal was to answer the what-if. I didn't want to just wonder, and when it flatlined on the fast and made that weird tone change I had to try the MSD
Originally Posted by 99 Black Bird T/A
Fantastic information to share with the LS community Darth & Tony. A+ gentlemen!
I hope tests like this convince FAST to consider releasing a shorter runner set for the cathedral FAST LSXR.
Sounds like if there was a Round 0 for out of the box comparison FAST vs MSD, the FAST would win say about 8 to 5 on Darth's point scale
. Lol. 8 wasn't high score. I just couldn't do a ten.
Originally Posted by Tuskyz28
A real world test would be taking a car to the track running it with the fast 102 intake then swap the intake for a msd unit and then compare the mph/e.t times.
Footnote.... I've seen a fbody with a 427 stroker using a ported fast trap over 140 in the quarter all motor. I'm still waiting for the msd to do so.....
That would be, but I'm not caging it to chase a mph. It's a street car. Hell I wouldn't have redone the leather if the plan was to cage it.
Originally Posted by AINT SKEERED
Yes i can see the msd being beneficial on my motor as i shift at 7000-7200 already.
Fast 90 may be for sale soon
Lol, I think so, but more especially if your cam has that later IVC.
Impressive gains with the msd. A mamofied msd would fit my set up better than the fast that I have. I would love to see what your car traps. A lot of tracks don't say much about street cars running with no cage. Especially on TNT nights
Lol, I think so, but more especially if your cam has that later IVC.
Its an f14 futral grind but this think loves rpm.
Thats through a 200 4r transmission with 4600 stall and 4.10 gears in a 12 bolt with 33 spline axles
Combo is a lq4 sbe dart 225s touched up but not not ported and 60 cc Chambers for 11/1 compression cometic .045 gaskets. F14 cam, fast 90 ported by futral . It did 460 speed density but went back to maf as i have a dry nitrous kit.
01-06-2017, 06:17 PM
Clash of the Titans - Mamo MSD Airforce vs Mamo Fast102 
