Transmission Options

[jabird56]

Hopefully BIG BLUE reviews this website, because it sure would be nice to see a 5 or 6 speed manual as an option in a MM.

[03SILVERSTREAK]

They would have to redesign the entire panther line from scratch. and you know what that means-$$$$$$$$$$$$$$$$$$$$$$$$..

[junehhan]

While a manual transmission wouldn't be necessary to have fun with this car, I think it seriously needs a 5, or even 6 speed automatic transmission that offers more gear ratio choices to fill in the gap. Maybe a 6 speed automatic would be excessive, but it does need a shorter gear to help it launch off the line without resorting to a rear end gear swap...........

[UAW 588]

Don't push it you guys. Just hope Ford Motor Company produces a Marauder for 2005. You got to have faith.:bows:

[Marauderjack]

I think mine has a "SIX SPEED"???:confused:

IT SHIFTS ALL THE TIME!!!!!:D

Marauderjack:cool:

[Hemlock]

WITH FORDS CLOSE TIES WITH ZF , A 6 SPD. AUTOMATIC COULD HAPPEN(I HOPE SO ANYWAY) !! CHEERS!!

[SergntMac]

It's already been done, but the owner doesn't post here. Installing a manual tranny is possible, reserve 4-6 large for the project. Most of the parts are available from the Ford Racing catalogue, except the tranny cross member, which could be fabbed.

Side affects to consider is the delivery of added power to the rear end internals and suspension previously absorbed by the auto tranny, and your desire to flog the bi*ch in a way you never have before. You may have to consider upgrades to the differential (31 spline? Auburn? Eaton? Torsen? Oh, screw it, just go 9") and suspension reinforcement, i.e. control arms, bushing, shocks, possibly traction bars.

If you're not adding any power under the hood, you may get away with a lower investment. However, if you're already supercharged, or will be, these issues will come to the surface eventually, and require additional expenses.

Would it be worth it? Probably not. OTOH, everything we do here with this car doesn't make any financial sense, so, why not? How bad do you want to drive a stick?

[cyclone03]

If Ford could beef the 5spd auto in my wifes Sport Track,I'd take one of those,that thing never seems to be lacking the right gear,plus it shifts,snick,snick,snick.

[RF Overlord]

Originally posted by SergntMac
How bad do you want to drive a stick?

I think Sarge has hit the nail on the head...30 years ago, when automatic transmissions were called "slush-boxes" for a reason, a manual trans would get better gas mileage, and be more efficient overall...today's auto trannys are MUCH better than ever, and I can't for the life of me understand why anyone would want to row their way around town with 6 gears in a 2-ton car...it'd be like driving a tractor-trailer...everytime you come to a stop sign, you'd have to go into "double under-compound third-range low" :rolleyes:

Today's electronically-controlled automatics, with proper programming, will shift far faster than a manual transmission, without providing all the shock-loading to the rest of the drivetrain, as Sarge detailed in his reply. Unless you're into enlarging the muscles in your right arm and your left leg, why bother with a stick? Or are you still high from watching "2 Fast 2 Furious" for the 17th time?

[jfclancy]

Would like to see the ZF 6 speed available mentioned here, I think the benefits of a couple extra gears would offset the expense. Of course this is the 6 speed automatic already offered by FORD .

Joe Clancy

[Marauderman]

Originally posted by Marauderjack
I think mine has a "SIX SPEED"???:confused:

IT SHIFTS ALL THE TIME!!!!!:D

Marauderjack:cool:

Now you know the reason why most of us hurriedly went and changed out the gears, chip ,stat, and plugs--i.e., stage 1....

Trust me/us all on this one--for sure--do this and those problems go away --and it's a whole new car---

Give Dennis a call---

Tom

[BillyGman]

with RF Overlord on this.......... there's been sooooo much talk and writing about 6 and even 7 speed automatics these days. Where is all of this going? Will we have a 10 speed auto by 2010??? IMO enough is enough. Just because "some" is good doesn't neccessarily mean "more" is better.
I absolutely relate to the comparisant to a tractor trailer truck.
I can fully understand there being a desire to leave the starting position quicker off of the line at the dragstrip or even at a traffic light w/this car, but installing a transmission w/Bazillion gears in it isn't a substitute for enough engine displacement. And make no mistake about it, the one thing that this "muscle car" lacks the most is cubic inches under the hood. And having more cubes under the hood would've provided this car w/more off-the-line low end TORQUE.....
And before you debate that, go to the dragstrip and race these Impala SS guys w/their big heavy cars, and you'll soon change your tune. In the stock configuration your Marauder will give these guys a ggod run for their money IF their Impala is stock also. And if you've perfomed MODS like I have, you'll smoke a couple of them like I did. But if you go up against those who have Moded their car as much as you have, then you'll see how much more 350 cubes under the hood responds to modifications than the mere 281 cubes that we have responds.
Now the displacement issue (or lack thereof) is no great revealation to me, since I've learned that concept many years ago, and I knew that even before i bought this car that it should've been offered w/a bigger V8. But it's one that I think some of us tend to forget about while discussing mods to this car. But please don't get me wrong, I love this car, and I'm constantly complimented on it as far as the way it looks, and as of late the way mine now sounds. I've siad this before, but I'll repeat it here......the MM looks way better than the Impala SS, or most anyother big car that I see on the streets or at the track these days. However, I'd rather have a 350 cube motor than a 281 cube one. it's just too bad that one isn't available for a cool car like the Marauder.

[greyghost]

I was talking to corporate the other day and there is no option of a different transmission in the future. They said as of now there is an 05 year planned. In fact they don’t have a kill date for the program since the MM sales are increasing they are going to see how far they can ride the wave.

I have the DR chip and all the stage 1 parts +. I am still not happy about how the 4R70W shifts. I think I will take it to Dennis and have the gear box modified with the high stall speed converter and big tranny cooler. That should make it bullet proof and ready for the S/C when I can make it happen. This is especially noticeable at WOT shifts and slow speed shifts. The clutches and band brake still catch on the WOT shifts as the J mod will correct this. Should be good for .5 to 1 sec quicker in the quarter. I also need to get my Kook’s exhaust installed. I have been looking at the rear end trailing arms and panhard rod. Kinda wimpy. Looks like a lot of flex and twisting and shifting of the rear end. Anybody considered any up grades for it??

The surge volume piece (Donkey Dick) on the intake has gone away on my car. I have made a aluminum billet plug and will post pictures tomorrow.

[junehhan]

Ya know, even the VW Beetle, Bug, or whatever the monstrosity is now comes with a 6 speed automatic. As stated earlier, while more gears will not be a replacement for displacement, it does allow the transmission to keep the engine in it's powerband more effectively, and I think that's where some of the issues are with this motor. On the WOT 1-2 and 2-3 shift, it feels like it's falling too far out of the powerband and that's why I think a 5 or even 6 speed automatic will really help. A CVT type stepless transmission is actually your most ideal setup, but I don't think there is even one available on the market yet that can handle this much power, although I might be wrong. I believe when a magazine tested an Audi A4 last year, the one with the CVT managed to outaccelerate both the automatic, and manual tranny A4...........



Marauderjack, have you tried locking out overdrive when driving around town? I have started locking out overdrive unless i'm going faster than 50mph, and it's really cut down on how often it keeps shifting and hunting for gears...........

[Marauderjack]

Yep.....I lock out OD and it helps but uless you give it a good bit of throttle it still shifts too soon!!:(

I hope these "chip/tuner guys" come up with something for our 04's soon!!??:confused:

Marauderjack:cool:

[Michael_S]

Originally posted by BillyGman
with RF Overlord on this.......... there's been sooooo much talk and writing about 6 and even 7 speed automatics these days. Where is all of this going? Will we have a 10 speed auto by 2010??? IMO enough is enough. Just because "some" is good doesn't neccessarily mean "more" is better.
I absolutely relate to the comparisant to a tractor trailer truck.
I can fully understand there being a desire to leave the starting position quicker off of the line at the dragstrip or even at a traffic light w/this car, but installing a transmission w/Bazillion gears in it isn't a substitute for enough engine displacement. And make no mistake about it, the one thing that this "muscle car" lacks the most is cubic inches under the hood. And having more cubes under the hood would've provided this car w/more off-the-line low end TORQUE.....
And before you debate that, go to the dragstrip and race these Impala SS guys w/their big heavy cars, and you'll soon change your tune. In the stock configuration your Marauder will give these guys a ggod run for their money IF their Impala is stock also. And if you've perfomed MODS like I have, you'll smoke a couple of them like I did. But if you go up against those who have Moded their car as much as you have, then you'll see how much more 350 cubes under the hood responds to modifications than the mere 281 cubes that we have responds.
Now the displacement issue (or lack thereof) is no great revealation to me, since I've learned that concept many years ago, and I knew that even before i bought this car that it should've been offered w/a bigger V8. But it's one that I think some of us tend to forget about while discussing mods to this car. But please don't get me wrong, I love this car, and I'm constantly complimented on it as far as the way it looks, and as of late the way mine now sounds. I've siad this before, but I'll repeat it here......the MM looks way better than the Impala SS, or most anyother big car that I see on the streets or at the track these days. However, I'd rather have a 350 cube motor than a 281 cube one. it's just too bad that one isn't available for a cool car like the Marauder.

I'm no auto expert, but the Impala SS uses a version of the LS1 engine, right? Isn't that a pushrod? The Marauder (and the Mustang Mach 1) uses a DOHC engine. I think it's difficult to compare pure displacement when you have two different engine configurations like that.

Correct me if I am wrong, but if the Marauder had a 5.7 liter DOHC engine it would probably drastically outdo the power output of the 400 horsepower 5.7 liter pushrod LS6 engine in the Corvette Z06.

[TripleTransAm]

Originally posted by Michael_S
I'm no auto expert, but the Impala SS uses a version of the LS1 engine, right?


???? Heavens no! The previous incarnation used a 'detuned' LT1 and the upcoming version uses a 3800 S/C'ed V6. (I say 'detuned' loosely... its LT1 didn't put down the same hp numbers as the F or Y cars, having given up some of the high end torque for something more useable in a 2 ton monster, ie. better torque at lower RPMs).



Correct me if I am wrong, but if the Marauder had a 5.7 liter DOHC engine it would probably drastically outdo the power output of the 400 horsepower 5.7 liter pushrod LS6 engine in the Corvette Z06.

Perhaps the hp rating would be higher...

But hp isn't something tangible... it's just a mathematical result on multiplying torque and RPM. A 5.7 liter DOHC engine would probably have huge heads with BIG ports to take advantage of the high revving... this kind of stuff would probably sacrifice low speed operation. Same horsepower, but due to what torque at what RPM? Now, if it was to come with some sort of electronic valve actuations (ie. the same sort of technology that makes Acura VTEC V6s so robust in torque delivery over a wide RPM range), then we'd see an engine of world caliber.

[junehhan]

Hey FORD!!!! ARE YOU LISTENING?

We want a 5.7 litre 32 valve quad cam v8 with variable exhaust/intake timing!

Such a motor if Ford was to build it, would not be cheap unfortunately............

[BillyGman]

Originally posted by Michael_S
I'm no auto expert, but the Impala SS uses a version of the LS1 engine, right? Isn't that a pushrod? The Marauder (and the Mustang Mach 1) uses a DOHC engine. I think it's difficult to compare pure displacement when you have two different engine configurations like that.

Correct me if I am wrong, but if the Marauder had a 5.7 liter DOHC engine it would probably drastically outdo the power output of the 400 horsepower 5.7 liter pushrod LS6 engine in the Corvette Z06.

No offence Mike, because i do appreciate your input, but I must tell you that this is wrong on both accounts. First, the 94-96 Impala SS used an LT1 motor, NOT an LS1 motor as TTA has pointed out.

Second, even if that were true, then yes, the Marauder would be faster than the pushrod motors of the same displacement, which only backs up my point all the more. And that point is that if you had some gonads under the hood to begin with, you wouldn't have to worry about putting thousands of $$ more into a transmission that has 6,7 or bazillion gears due to lack of pure off the line TESTOSTERONE.............

[Michael_S]

Hey, no offense taken. That's why I make comments and ask questions - to learn.

Let me rephrase my statements a little and see if I can get you to agree with it. If you can't, hey... so I learn some more.

All other things being equal, a regular (non racing, non custom configuration) DOHC engine will have a higher horsepower output than a regular (non racing, non custom configuration) pushrod engine of the same displacement. The torque curves will be different, and the pushrod may make more torque down low, but the peak horsepower of the DOHC will generally be higher.

So, while more displacement = bigger engine, if you wanted a DOHC naturally aspirated engine to match the peak power output, of, say, the 500 horsepower Viper V10 you wouldn't need to have anywhere near the Viper's 8.3 liters of displacement. (Now if you want to match the Viper's 525 ft*lbs of torque available at relatively low RPMs, the size difference gets much smaller).

[BillyGman]

I'm getting your point now since you've explained it that way, however to be honest w/you I must say that I'm not really sure about that. What I mean is that to my knowledge, the reason why the overhead cam motor makes power higher up in the rev range, and has a higher reving redline, is simply because w/that design you don't get as much valvetrain flex nor as much valve float as you do on a pushrod engine.

However, weather or not you would actually get less low end, or low RPM power w/an overhead cam motor of the same displacement and same cam lift and duration as w/the pushrod engine, I'm not really positive on that. I've tended to think that w/the overhead cam design you simply have a wider powerband. In other words the same low end power along w/greater hi-RPM power due to lack of valve float.

Again, I'm not positive on that, but this has been my understanding on these motors. It might be difficult to find a side by side dyno test on two motors of the same displacement and cam specs, w/the only difference being the valve train design. And ofcourse that's what we would need to know the answers to these things for sure.

So you have brought up a very interesting question I will admit. I just don't know the answer to that specifically.

[TripleTransAm]

Originally posted by Michael_S

So, while more displacement = bigger engine, if you wanted a DOHC naturally aspirated engine to match the peak power output, of, say, the 500 horsepower Viper V10 you wouldn't need to have anywhere near the Viper's 8.3 liters of displacement. (Now if you want to match the Viper's 525 ft*lbs of torque available at relatively low RPMs, the size difference gets much smaller).



Precisely why I don't give a hoot about peak hp numbers, unless you consider them inclusively with the RPM the peak numbers are obtained at, but with the torque peak and its RPM as well. I mentioned a turbo'ed S2000 that my cousin worked on this past Fall in another thread... he told me that car was developing a flat power band over a broad range, and ultimately over 300 hp at the wheels from 5000 RPM to somewhere like 7000 RPM. Wow... impressive...

... or is it really?

Think about it... hp = torque x RPM / 5252. At 5000 RPM, if the car is putting down 300 hp, that's about 315 lb-ft at the wheels. Pretty good acceleration at that speed to be sure. Now let's look at that same 300 hp at 7000 rpm... 225 lb-ft. Still impressive that it can put out 225 lb-ft at that high RPM, but it's still 225 lb-ft.

So then comparing that with my LS1's over 300 lb-ft torque delivery from just under 2000 RPM until about 5500, it still results in a peak 310-ish hp at the wheels around 5500 and dropping off thereafter. So you'd think the other S2000 'higher horsepower' car was stronger, right?

Well, torque is what's directly related to acceleration. Basic physics (Newton's equations, etc.) show Force = mass x acceleration. For a given mass, you need a certain force for a certain acceleration. That force is what's applied at the tire contact patch, which is located one tire radius distance away from the axle, the point of application of torque (twisting force). So how does torque applied at the axle related to the force applied at the tire contact patch? Another equation... torque = force x distance-at-which-its-applied-relative-to-some-anchor-point.

So, really, the only reason that S2000 pulls mid-to-high 12s in the quarter is because it's light... and probably because the engine operating range is so wide, you can stay in lower gears longer and benefit from the improved torque multiplication in the lower gears.

Hence why big hp numbers from rev-happy engines don't impress me too much, unless there's a good torque / RPM combination that goes along with it.

[Michael_S]

TripleTransAm,

From what I understand, peak horsepower and horsepower to weight ratio is a good indicator of performance when the race will be from a dead stop and not a rolling start, with some serious clutch drops going on.

That's why, unless I am mistaken, the Mazda RX8 (159 ft*lbs of peak torque but 238 horsepower at 8500 RPMs) or the first generation Honda S2000 (153 ft*lbs of peak torque but 240 horsepower at around 8000 RPMs) can get sub 6 second 0-60 mph times despite such low peak torque. From a dead start like I listed, they can rev really high and drop the clutch to take off already in the car's power band.

A stock Trans Am is still faster than either car in a 0-60 mph run, but considering the massive power difference the gap is small. Now make it a 5-60 mph race, where clutch drops are impossible, and the Trans Am will positively annihilate them with its monstrous torque available right from down low. (Or, make it a 0-60 mph run with drivers that don't care to burn out their transmissions in short order by using clutch drops.)

For whatever reasons, some guys enjoy having to rev a car half to death to get any juice out of it. I don't think any of them frequent forums like this one, :D but they do exist.

[Michael_S]

Originally posted by BillyGman
I'm getting your point now since you've explained it that way, however to be honest w/you I must say that I'm not really sure about that. What I mean is that to my knowledge, the reason why the overhead cam motor makes power higher up in the rev range, and has a higher reving redline, is simply because w/that design you don't get as much valvetrain flex nor as much valve float as you do on a pushrod engine.

However, weather or not you would actually get less low end, or low RPM power w/an overhead cam motor of the same displacement and same cam lift and duration as w/the pushrod engine, I'm not really positive on that. I've tended to think that w/the overhead cam design you simply have a wider powerband. In other words the same low end power along w/greater hi-RPM power due to lack of valve float.

Again, I'm not positive on that, but this has been my understanding on these motors. It might be difficult to find a side by side dyno test on two motors of the same displacement and cam specs, w/the only difference being the valve train design. And ofcourse that's what we would need to know the answers to these things for sure.

So you have brought up a very interesting question I will admit. I just don't know the answer to that specifically.

I'll be honest, I don't even know what valvetrain flex or valve float are. You obviously know more about this stuff than I do. If you don't mind, could you explain what it is for me or point me to a website that does explain it? Thanks.

I was only making a guess when I said that pushrod engines make more torque down low. From what I've read, DOHC performance engines like the one in the Marauder or Cadillac's NorthStar V8 are good down low but superb past 3000 RPMs, give or take. I figured that GM keeps using pushrods for the Corvette and Chrysler uses pushrods for the Viper because they offer some other advantages down low. I would not be happy to learn that they put pushrod engines in their 'halo' cars just because they were trying to save some money.

[TripleTransAm]

Originally posted by Michael_S
That's why, unless I am mistaken, the Mazda RX8 (159 ft*lbs of peak torque but 238 horsepower at 8500 RPMs) or the first generation Honda S2000 (153 ft*lbs of peak torque but 240 horsepower at around 8000 RPMs) can get sub 6 second 0-60 mph times despite such low peak torque.


Good examples... you didn't list where the peak 153 lb-ft of torque happens on the S2000, but the 240 hp at 8000 works out to about 158 lb-ft. So, taking into consideration some rounding off of either the peak hp number or its RPM, that means a pretty much flat curve from wherever that torque peak is until 8000 RPM where it has to begin to drop off faster than the RPM increases. This is what ensures steady acceleration over a wide RPM range.

Don't forget the actual car weight... it's still only 153 lb-ft... and in a heavier car you can pretty much forget those 153 lb-ft being able to muster those sub 6 second 0-60s... ;)

Here's another good example of why both torque and hp numbers (and their RPMs) have to be considered. My 1978 400 gas guzzler is supposed to develop a peak torque (at the crank) of 325 lb-ft at just 1600 rpm. The listed peak horsepower of 180 comes in at 3600. That hp peak at 3600 translates to about 262 lb-ft, and it drops off quickly thereafter (otherwise you'd get a higher hp peak at a higher RPM). The numbers are big, but 0-60 sure sucks. Most times, I swear I get better 50-85 mph rolling acceleration results by letting it stay in 3rd gear instead of forcing a downshift, the above-4000 RPM performance is so useless. :(

[BillyGman]

you've asked a question that will take a discriptive answer, but I'll do my best. here it goes:

VALVETRAIN FLEX:

This is a common thing w/your typical factory stock vavletrain(uh, the "valvetrain" meaning camshaft, lifters, pushrods,rockerarms,rockerarm studs, valves, and valvesprings). The best analogy I can think of at the moment to describe valvetrain flex and deflection is when you're using a ratchet with a very long extension to tighten a large bolt that requires a great deal of torque on it to tighten it sufficiently(such as a 7/16" bolt that would usually require about 65 ft/Lbs of torque like the cylinder head bolts on a V8Chevy small block engine). If you need to use a long extension on your ratchet or torque wrench to get at such a bolt, you'll find that before you'll reach the required torque needed to securely tighten the bolt, there will be substantial flexing, or twisting of the extension you're using. Especially if the extension is 12" long, or longer, or if it's a narrow extension such as one for a 3/8" drive ratchet. So the longer and narrower that extension is, the more difficult it will be to reach the torque required to properly tighten the bolt in question which will be very apparent when you're using a torque wrench w/that long extension.

Likewise w/a valve train that is lengthy, and has a number of moving parts, and also has various angles at which those parts meet. Thus is the inherit weakness of your typical factory stock valvetrain, on a V8 pushrod engine. There will be a certain degree of flex and deflection occuring between the various components of such a valvetrain because of the long chain of parts that are included in such a valvetrain. And this flex that occurs becomes greater at high engine RPM's, and at high torque situations such as at Wide Open Throttle(WOT).

And if you need more specificity, then let me explain that this valvetrain flex can come from many different areas. One example would be the pressure that the pushrods exert on the end of the rocker arms, which in turn causes rocker arm flex and deflection, which can distort the valve timing (which is the time at which the opening and closing of the valves occur), especially at high RPM engine sppeds, and at WOT. One other example of this flexing of the valvetrain is at the rocker arm studs which also are known to flex. Particurely w/higher HP engines, and engines that have more valve lift than .450". It's for particularly this reason why racers at the dragstrip w/high HP engines will have go fast Hi-perf goodies in their valvetrains such as rocker arm stud girdles, which are two piece aluminum or steel bars that bolt together around extra long rocker arm studs and are installed on top of the rockerarms and underneath the valve covers to prevent this valvetrain flex that occurs from rockerarm studs. Another hi-perf racing part is the thicker rockerarm studs, as well as heavy duty stainless steel rocker arms. None of which are ever offered on factory stock cars.

Now the bottom line w/this description of valvetrain flex is that all of this causes a loss of power due to the valve timing events(ei., the opening and closing of the intake and exhaust valves) being deviated from the optimal specifications. And this valvetrain flex, valve timing deviation, and subsequent power loss, will occur the most at high RPM's and become greater and greater the higher the engine is reved.

This flexing and deflecting of the valvetrain is substantially reduced (although not eliminated completely) w/the use of an overhead camshaft, due to the valvetrain being shorter because of the camshaft being relocated much closer to the valves. This acts the exact same way as if you were able to take that same 12" long ratchet extension, remove it from your torque wrench, and replace it w/a shorter extension such as a 3" one. That would greatly reduce the flex that was occuring and able you to get a greater degree of Torque on that bolt that you needed to tighten. Likewise the valvetrain of the overhead camshaft engine. And the benefits from such a valvetrain design are multiplied in the high RPM range.

VALVE FLOAT:

Valve float in the V8 engine will usually be more likely ALSO at high RPM's. A high performance engine is much more prone to this occurence due to the camshaft Lobe profiles being more extreme. BY "extreme" I mean that the valve opening and closing ramps of the camshaft lobes themselves are ground to be steeper due to the greater durations, and higher valve lift specs of a high performance camshaft. The more lift the camshaft provides, the more the valves open, and the more the engine breathes due to more air/fuel mixture going in, and out of the motor. Which ofcourse in turn creates more power. Likewise w/greater camshaft durations. The longer the duration is, the longer the valves will stay open. Again, this translates to more air/fuel mixture going into the engine, and a quicker , less restrictive exhaust exit flow.

Now the following is key to understanding valve float.......the greater the lift and duration spec of a camshaft, then the more extreme the cam profiles are since the cam lobes have to be ground w/steeper opening and closing ramps in order to oepn and close the valves quicker. And with the steeper opening and closing ramps on such a camsaft lobe, the more likely it is that at high engine RPM's, the lifters will have a tendency to skip off the ramps. This is particularly evident on the closing ramps of the camshaft lobes. So in other words this occurs while the intake and exhaust valves are closing.

Now with this valvefloat occuring on the intake lifters, it will in turn cause the intake valves to remain open longer than intended during the upward movement of the pistons while they're in their compression strokes. And that causes a loss of compression since compression will NOT occur until both the intake and exhaust valves of any given cylinder are completely CLOSED. And needless to say, a loss of compression will cause a loss of power.

This occurence will usually take place w/most ALL pushrod V8 engines between 6000 RPM, and 7000RPM with factory valvetraions, and even w/many engines w/high perf valvetrains that are of the pushrod design that use hydraulic lifters. Note that hydraulic lifter engines are more prone to this occurence than solid lifter engines are. And because virtually all mass produced factory automobiles these days come equiped w/hydraulic lifters weather they be of the roller cam design or the conventional flat tappet design, this engine RPM limitation due to valvefloat applies to ALL factory stock engines regardless of other factors such as N/A vs. Supercharging.

Infact w/hydraulic Lifter factory engines that are equipped w/roller camshafts, this valvefloat has been known by engineers to occur at lower RPM's than that which I've stated above. And that is directly due to the more extreme Lobe design of the roller camshafts(ei steeper opening and closing ramps).

On the exhaust valves, this valve float will rob power but in a different way since the float occurs during the intake stroke of the engine rather than during the compression stroke as with the intake valves. Therefore the power loss that ensues isn't because of compression loss, but rather due to contamination of the air/fuel mixture being drawn in during the intake stroke, since the exhaust valves are remaining open longer than intended. But what's more is that that less fuel will be drawn into the cylinders anyway since the suction action of the descending pistons during the intake strokes is being compromised because of the floating exhaust valves remaining open too long.

Now incase you're tempted to ask...."well why doesn't the engineers of the V8 engine camshaft designs compensate for this valvefloat occurence by redesigning the camshaft lobe specifications to make up for this valvefloat?" That's a non-issue. "Why?" you ask? Because this occurence of valvefloat doesn't take place at all engine RPM's. It only occurs at high RPM's provided that the proper and optimal valvespring pressures are used. Therefore if you were to attempt to design a camshaft profile to reduce valvefloat, then it would produse less power at mid-range, and low RPM's. Which would ofcourse would result in reduced acceleration, and slower ET's at the track, thereby defeating the whole purpose.

The only thing that I have to add to this is that it's my guess that valvefloat w/an overhead cam design valvetrain is also less likely, or reduced because different angles of the valves in relation to the camshaft lobes, as well as in relaton to the lifters themselves. Valvefloat is somewhat also reduced in pushrod engines by adopting higher valvespring pressures, although you can only make a valvespring so stiff, since there is a point at which the valvespring pressure will be so high that it would increase the wear of various parts in question such as, lifters, valvestems, and even the camshaft lobes.

And that is precisely why with very high lift radical solid lift roller camshafts that are used for racing, the rebuilding of the lifters is often required once every 2,500 miles due to the extreme valvespring pressures that are needed for the lifter to follow the profile of the radical cam lobe profiles of those cams.

Okay, I hope this long explanation has increased your understanding of valvetrain flex, and valvefloat.An answer this long was difficult to avoid since you've asked a question that deals w/complex issues.

.....hmmmmmmm, maybe I might as well have written my own book on this subject, uh?

[TAF]

Paragraphs!!!!:banana:

Billy used Paragraphs!!!!:banana2:

J/K Billy...well done. :up:

[BillyGman]

I knew someone was going to comment about the paragraphs.........I just wasn't sure who it was gonna be......

TAF, I bet MAC wishes that he beat ya to that comment. I figured I had better use paragraphs w/a post that long. Otherwise it would've looked like a giant concrete wall of words.:D

[jgc61sr2002]

Billy - Very well said. Excellent.:D :up:

[SergntMac]

Excellent presentation, Billy, thanks for the effort.

[woaface]

So if they offered a 5 or 6 speed manual, I think they should then beef up the automatic to a 5 speed. The Motego is gonna have a 5 speed auto eh?

I can't remember where, but I swear I heard that they're completely remaking the panther platform from the Crown Vic up, and that the Marauder will be discontinued for a year or two and be brought out sometime after 2006.

[Michael_S]

Originally posted by BillyGman
you've asked a question that will take a discriptive answer, but I'll do my best. here it goes:
*snipped*



Holy cow. Thanks so much for the explanation. I believe I actually understood that. Let me try to make a summary to see if I have things straight in my head:

When you are applying leverage to an object, there is a tendency for your lever to bend a little or twist as the force is transferred through it. This takes place in car engines too. It usually isn't too much of a problem, but at high RPMs a few millimeters of valvetrain flex here and there can rob power by disturbing the optimal timing for valve opening and closing. If I understood your explanation right, the flex would generally open valves a little later than it should and then close them a little earlier than it should.

The valves are themselves opened and closed by the camshaft, which is spun by the lobes being pushed by the rods in a pushrod or a belt around the cams and the crank in an OHC engine. When the engine is in high RPMs, the fast spinning can cause some of the valves to skip, staying open for an extra revolution or closed for an extra revolution - valve float. That can either rob a cylinder of compression during the combustion or allow exhaust to remain in the cylinder and rob power that way.

So I'm guessing that the ideal way to fix this would be completely electronically controlled valves, so that you could prevent power loss at high RPMs without using super tense springs or sacrificing power on the low end. Am I right? The neat thing about electronically controlled intakes and exhausts is that a few keystrokes could probably change your performance profile from optimized for fuel efficiency to all out hot rod and back.

[SergntMac]

Originally posted by woaface
I can't remember where, but I swear I heard that they're completely remaking the panther platform from the Crown Vic up, and that the Marauder will be discontinued for a year or two and be brought out sometime after 2006.
ROTFLMAO! Yeah, we heard that silly rumor too...LOL. No worries though, the MM will be here in '05. Y'all heard about the decontenting of the N/A option, right?

[BillyGman]

maybe I'm a bit slow on this, but I just realized that we're kinda making this into a dual thread here. I blame myself for getting off the topic, but maybe I shouldn't drift anymore off of it.
You have the basic understanding of what I said yes. But I don't know of any other way that valves in a piston, gas powered engine could be operated other than by mechanical means.

..and when I said the lifters can skip off the cam lobes, I didn't mean so much that the cam lobe turns a full revolution before the lifter falls back down onto the cam lobe profile. That would be disasterous!!!!!!!!

...and BTW, the camshaft in an engine isn't propelled or "spun" by the pushrods exerting pressure on them. The Camshaft is turned by the force of the crankshaft which is yoked together w/the camshaft via timing gears, and chain. So it's the cam lobes spinnig around that pushes up on the lifters which in turn lift the pushrods up and down. Too bad you didn't have one of those visible V8 engine models when you were a kid. They came w/an electric motor that caused the whole assembly to reciprocate just as it does inside a real V8 engine in a car.

[TripleTransAm]

Will this do? http://auto.howstuffworks.com/engine-cam.htm
http://auto.howstuffworks.com/engine.htm
(it's an overhead cam engine, but just imagine the pushrod acting between the cam lobes and the rocker arms visible in the second link)

I used to have one of those cutaway V8s with an electric motor driving all the reciprocating parts, long ago when I was a kid. Numbers matching, I spun a bearing when I took it past redline while racing the neighborhood bully, had to sell it to a classmate real cheap for beer money.
(just kidding! ;) but I DID have one of those cutaways... they rotated at something like 2 RPM???)

[BillyGman]

Originally posted by TripleTransAm
I used to have one of those cutaway V8s with an electric motor driving all the reciprocating parts, long ago when I was a kid. Numbers matching, I spun a bearing when I took it past redline while racing the neighborhood bully

LOLOLOLOLOL!!!!!!!!! ....that was priceless.

actually, I never had one, but my twin brother did when we were 8 yrs old. I don't think that they even make those models anymore. No wonder why so many young guys these days are ricers!!!!!! I wonder if the Honda manufacture bought out the rights to those visible V8 engines to get them off the market. They must look forward to their future target customers.:rolleyes:

[bob35222]

I think that the use to which a car is put greatly influences the most desirable engine properties. Most of the enthusiasts on this site are muscle/drag car oriented, acceleration from a dead stop and or low ETs in the 1/4 mile are the desired performance characteristics. The overhead cam engines have terrific power in the upper end and would be fantastic for road racing. The car is already underway and one just works the car from 3k to 6k rpm depending on the situation. I just made a fairly high speed run back from visiting my folks in Chicago and enjoyed that aspect of the Marauder's engine very much. Once underway this is a terrific motor. Of course selectable, if not manual, gears would be great. Some of the stick like automatics as in the Infinty G35 might be just the thing, in five speeds probably.

Bob

[bob35222]

My comments above were inspired, in part, by a short article in the Dec '03 MM & FF magazine. In a short article on page 24, headlined "03 COBRA FASTEST STREET MUSTANG AT BONNEVILLE" tel the story of the car which set a new Bonneville C-Production Supercharged record of 176.42 miles per hour. The best part of the story is that the car was driven to Bonneville from Georgia for the event and then back home. Just a different kind of fast. Bob

[bob35222]

Oh yeah, great thread and very informative, I would like a five speed auto, isn't there one on the Avaitor? Bob

[BillyGman]

I think you have a very good point there about this engine's potential for other types of racing than at the dragstrip. I guess most of us don't think of a car like the Marauder as a candidate for that type of racing. Maybe that's because of the mammoth weight of these cars. But hey, who would think that we would be racing such a heavy car at the dragstrip? Right?

[Michael_S]

Thanks for the info BillyGMan and TripleTransAm. I appreciate it.

I should take a few automotive classes, really I should. I'm just too busy wasting my time on internet forums to get anything done ;)

[BillyGman]

it's all cool Bruh........

[Thomas C Potter]

Autostick baby!! Would be so sweet!!

[junehhan]

The Marauder I think, would benefit incredibly if a sportshift, or manuamatic option was given. Because of the goofy shifting habits this transmission has stock, it really would be nice to have the ability to hold the transmission in a specific gear as long as you would like, and shift only when you want it to shift.

[swc69]

Junehhan -

Exactly, being able to keep the engine in its power-band in any gear. That would greatly increase the drivability and enjoyment of our MM's.

For me - I've never liked the slight delay you get with a manumatic or autoshift. Of course, I never liked the idea of spending $5k to convert my auto to a manual.

I wonder if my dealer would consider that as voiding my warranty?

SWC
2003 300A

[Michael_S]

Originally posted by swc69
I wonder if my dealer would consider that as voiding my warranty?


(Don't take this as definitive word, just as rumor.)

From what I understand, if you make any modifications to your car and then request repairs under warranty, if they deny coverage it is your responsibility to prove, in court, that your modifications did not affect the defect. That can easily be more expensive than just fixing the problem out of your own pocket.

Like I said, that's just what I've heard.

[Kennyrauder]

Dennis did a stage 1 S/C & reprogrammed my tranny shift points & I must say this Marauder is way better on the road for shift points & obviously real quick. Regards from Canada ....Kennyrauder.