Shedding pounds?

[rurumon]

Taking the beast to Natural Bridge 1/8 mi. tomorrow, Just wondering if you guys know of any ways to shed some extra weight. Can we remove our mufflers or is there an O2 sensor back there, I figure those things have to weight at least 50 lbs total.

[martyo]

rurumon: I was under my car yesterday. I do not believe that the mufflers had O2 sensors, so you should be able to uncork the exhaust of you are so inclined, but it is going to be a lot of work. The exhaust system is heavy with the mufflers, pipes, and baffled tips. Be prepared for a lot of work to drop it all down, especially if you are not on a lift when you do it.

I suppose you could also take out the back seat, the spare tire and the trunk organizer......

[TAF]

Let's see..."How to shed pounds at the track"....

Well....for most on this site.....we'd have to find another driver :lol:

Obviously, that's not a concern for you if taking off mufflers is a plausable option.

[SergntMac]

OEM mufflers weigh about 30 pounds more than turbos, each, insulated and sound proofed as they are. If you have upgraded to turbos, keep your exhaust system closed. If not...

From the back, looking forward, everything exhaust related before the H pipe junction (on the MM) is safe to remove. Unbolt what you want.

May not help you any to run open pipes, but the O2 sensors are up between the dual cats, just so you know.

Leave your spare tire behind.

Remember that gasoline weighs 8 pounds per gallon, run what you need to run, and make the return trip.

Check your tire pressure, OEM and delivery pressures run from 24 to 32 Lbs., a "comfort" setting. 35 Lbs. works for me, and I have heard favorable reports from pressures up to 40 Lbs., you drive and you decide.

OD off.

Climate control off.

Give yourself some leg room, adjust the seat and pedals so you bend at the knee, and can hit the floor on WOT. Likewise bend for the elbows. Be free to control the car. Seat backs straight up, tilt wheel to your taste, dial in your own "seat of the pants" driving aspect. Be comfortable, and always in control.

Without knowing more about your mods, your launch could go two ways.

Go easy, stage her shallow. Brake torque to 1000, maybe 1500 RPM, you'll have to feel what's right here.

If you have any mods, just "spank" her hard and run with her on the green.

If not...If you are bone stock, try a "1, 2, 3, 4..." count in your head while you push her down to WOT. This needs a beat playing in your head, to work against the lights...

Practice.

Let us know how any of this works, k?

[TripleTransAm]

Originally posted by SergntMac

May not help you any to run open pipes, but the O2 sensors are up between the dual cats, just so you know.


I recall you briefly operated your MM with no mufflers. What was your seat-of-the-pants impression regarding the 4.6l DOHC's low end response?

Some of the older traditional V8s required a little bit of backpressure to maintain a good low-end response... running with open pipes (ie. nothing from the headers or Y-pipes back) would render the car totally useless at the low end. However, from what I've read and experienced, GM's LS1 engine seems to love a free-breathing exhaust without suffering much (if at all!) on the low end. Now, the big thing about the LS1 besides the cavernous head ports is the totally revamped ignition firing order. An unreliable source once told me this new firing order was the same as on the Ford V8s (whether he was referring to the older motors or the new DOHCs, I dunno).

So, cavernous ports... Ford firing order... do you see where I'm going with this? The 4.6l is nearly as quiet as my 5.6l LS1 at idle, another byproduct of the revised firing order. So I'm wondering if the 4.6l DOHC will respond to an open exhaust the same way the LS1 does... in a very favorable manner?

[Menace]

4 lug nuts wieght about 1lb. If you take 2 or 3 off each wheel you can shed a few more lbs. :lol: :rasta:

[LincMercLover]

Don't bother with the back seat. It weighs MAYBE 5lbs...

[rurumon]

So, PITA to remove everything after the H. I would think it wouldnt be much more than a couple of retaining bolts and clamps, but after seeing that the pipes go over the axle, I am thinking I would have to drop it in order to get the pipes out. this seem true? if so, it seems like a bit too much trouble.

Then again, 100 or so lbs is alot of weight. Torque brake to 1000-1500 rpms you say? sounds like a plan.

[CRUZTAKER]

Originally posted by TAF
Let's see..."How to shed pounds at the track"....

Well....for most on this site.....we'd have to find another driver :lol:

Obviously, that's not a concern for you if taking off mufflers is a plausable option.

The Dynomat...yes, the dynomat must be the FIRST to go!!!

[martyo]

Originally posted by rurumon
I am thinking I would have to drop it in order to get the pipes out. this seem true?

Yep. Look before you leap!

[Wags]

TAF,

I hear ya' about lighter drivers. I have a program that will go over your engine and drivetrain components for optimum performance, and it it always lists "lighter driver needed" as one of the recommendations for a quicker 1/4 time. It's bad when even your computer tells you you're fat.

Wags

[Warpath]

Originally posted by TripleTransAm
Some of the older traditional V8s required a little bit of backpressure to maintain a good low-end response... running with open pipes (ie. nothing from the headers or Y-pipes back) would render the car totally useless at the low end. However, from what I've read and experienced, GM's LS1 engine seems to love a free-breathing exhaust without suffering much (if at all!) on the low end. Now, the big thing about the LS1 besides the cavernous head ports is the totally revamped ignition firing order. An unreliable source once told me this new firing order was the same as on the Ford V8s (whether he was referring to the older motors or the new DOHCs, I dunno).

So, cavernous ports... Ford firing order... do you see where I'm going with this? The 4.6l is nearly as quiet as my 5.6l LS1 at idle, another byproduct of the revised firing order. So I'm wondering if the 4.6l DOHC will respond to an open exhaust the same way the LS1 does... in a very favorable manner?

Generally speaking for Cobras, lowering the back pressure reduced low end torque from what I have seen on dyno graphs. These engines have such low low-end torque that the difference may not be seen by seat of the pants meter. A 2.5" exhaust is fine. A 3" exhaust seemed to lose torque. Both are on naturally aspirated engines. Blown engines are different of course. Types of exhaust make a big difference too.

[TripleTransAm]

Originally posted by Warpath
Generally speaking for Cobras, lowering the back pressure reduced low end torque from what I have seen on dyno graphs. These engines have such low low-end torque that the difference may not be seen by seat of the pants meter. A 2.5" exhaust is fine. A 3" exhaust seemed to lose torque. Both are on naturally aspirated engines. Blown engines are different of course. Types of exhaust make a big difference too.


Thanks. Good info. I assume the MM engine will behave similarly.

On my WS6, I spend so little time below 1500 RPM that I didn't really notice a difference in low end. What I did gain was going from a totally silent engine below 1500-2000 to something that made V8 sounds at anything above 1300 RPM and sounded REALLY good above 2000 RPM. That LS1 really works so well from 2000-6000 RPM that I sometimes wonder if the apparent loss of low end is really a misinterpreted enhancement in the 2000-6000 range!

For those of you curious how it sounds:

http://firebird.freeservers.com/ws6-old/ws6rev_1.mp3
Taken with a camcorder sitting in the passenger seat, on a gentle cruise down a busy boulevard going to get gas in 2001.

http://firebird.freeservers.com/ws6-old/exh2.wav
Taken in 2000 a few days after I did the exhaust mod, by a buddy holding a cheap camcorder about 30 feet behind the car in a parking lot.

I was hoping to get that type of sound out of the MM. :coolman:

[Macon Marauder]

Steve,

That's pretty cool. We need more audio! Video is good too...

I don't have any files to upload, but I KNOW my Marauder is louder now - after 4000 miles I can really tell a difference.

My Japanese-built-loving, 4-cylinder-hugging best bud (I know, I know) gave the MM a compliment yesterday: "This thing has a nice growl to it."

Not as deep as your WS6 but still sweet music to my ears.

PS: What was this thread about again? Oh yeah - shedding pounds. Well, at 6ft 160 I don't really worry about that...
;)

[TripleTransAm]

Originally posted by Macon Marauder

That's pretty cool. We need more audio! Video is good too...

Weather's getting real nice up here, so once I wash the girl you can expect some sort of multimedia on this car. I know I once heard a .wav file of the MM starting up and revving, and that REALLY got me excited about the car, and started my 3 month odyssey culminating in my eventual purchase. Mensrea's burnout videos really helped as well. Hopefully I can add to the library of available MM material.

Back to the topic: Sarge mentioned running low gas quantities to minimize track weight. I've heard from several sources that the LS1 computer will retard spark advance each time it detects knock, and after a certain threshold, it just plain switches to a less aggressive spark curve. It only resets back to the normal curve after it detects a minimum fillup quantity of 20 liters. Is this the case with the MM's PCM too?

If it is the case as in the LS1, then there's always the risk that the older gas might have sent the PCM into a less agressive curve. In some cases, my WS6 has shown up at a track running 14.5s after some aggressive street driving, and after a quick ~20 liter fillup at a nearby station, it returned to solid 13.5s once I got back on the track.

I'm really curious if the MM PCM behaves this way too.

[MAD-3R]

Not noticed. My times, in my sig were on alittle over 1/4 a tank.

[O's Fan Rich]

:puke: Or do this after 1 meal per day!
On a more serious note, I wonder how hard it would be to remove the passenger seat, rear seats, everything in the trunk.May not be feasable.
Drain the washer fluid?

[jgc61sr2002]

Originally posted by rurumon
Taking the beast to Natural Bridge 1/8 mi. tomorrow, Just wondering if you guys know of any ways to shed some extra weight. Can we remove our mufflers or is there an O2 sensor back there, I figure those things have to weight at least 50 lbs total. Remove the spare tire, Jack and anything else in the trunk. Leave the exhaust alone too much work to remove and too little gain. Good luck. John:up:

[looking97233]

The front seats are heavy, mabye buy a drag seat, and change out when going to race? Don't forget about the airbags in the seats. BOOM! They can break bones if you get hit hit by them right.

[TripleTransAm]

Originally posted by Rich_Long
:puke: Or do this after 1 meal per day!

LOL, regarding Atkins. My wife and I are trying it out... working great. I've lost about 14-16 lbs over the past month and I'm eating like a pig! When I reach my target weight, I'll go back to a calculated mix of carbs and fat... I don't believe in extremes.

[SergntMac]

Originally posted by TripleTransAm
I recall you briefly operated your MM with no mufflers. What was your seat-of-the-pants impression regarding the 4.6l DOHC's low end response? I'm wondering if the 4.6l DOHC will respond to an open exhaust the same way the LS1 does... in a very favorable manner?

Yes, TTA, I spent a week with no mufflers, just OEM tips, which confirmed that the OEM tips are in fact, resonators too. The overall volume was borderline legal, like "life support" borderline, eh?

The straight pipe exhaust issued more noise than tone, let alone anything "adorable" to us. It was almost painfull to human hearing, and well out of sync with what you would expect once your hearing identified the car in traffic. Dogs would never chase after my tires. They would run the other way, if they could run at all.

The high pitched "whine" produced was like that of a Penske Indy motor, and not what you would expect to hear from a big, bad and really fast American muscle car, surely not the sound of a sedan of the MM's nature. The results were such, that measuring any performance gain was not debated. I didn't care what hidden power resided in a straight pipe conversion, the sound alone, said it's not worth it.

All the "seat-of-my-pants" meter recorded, was my tail beating between my legs after a number of stop light snickerings. The only way I could get away with this mod, was to rebadge my MM as a Subaru WTF.

Sorry, this isn't a favorable option, by any measure.