Easy mod shaves nearly 20lbs.

[GR40Freak]

As most of you know we won't sell anything that we don't use ourselves and have proven effective in race/track conditions.

 

A while back I installed a lightweight AGM battery in my GR40ST. I drive the car daily and track it 'hard" at least once a month with this battery installed.

 

I got the setup from HP Autowerks in Santa Barbara.

http://www.hpautowerks.com/

 

HP Autowerks is a high end german tuning shop, but the kit they have for the 1991-2009 BMW M3 is a direct fit for the S197 Mustang/Shelby. The guys at HP are nothing less than first rate.

 

The battery is made by Braille Battery USA:

http://braillebattery.com/

 

The battery/hold-down kit is available here:

http://www.hpashop.com/product.sc?category...mp;productId=45

 

Or you can contact Harold @ (805) 966-3200.

 

It is available with three different batteries. 11.5lb, 15lb, and 21lb and are available with a real carbon fiber wrap (looks cool but not necessary and saves no weight)

 

All three batteries exceed the CCA rating of the stock Ford battery.

 

I'm using the B2015 15lb. battery and have no issues. It took 19lbs. off the nose of the car, verifed by our shipping scale and vehicle scales at the shop. It bolts in using the stock battery clamp and literally took me 5 minutes.

 

It does need to be said you cannot sit in the car with the engine off and listen to the stereo for hours and expect the car the start. That being said it is a great upgrade.

 

Colin Sebern

Griggs Racing

[greaser]

now someone make a plate so we can get rid of the ginormous stock mounting plate. other then that it looks like a great thing i just put one in my 107 CI harley and it spins that thing like its a honda.

[stump_breaker]

I had no idea a nine volt battery was strong enough to work in our cars!

 

That thing sure is small...

[zdle]

As most of you know we won't sell anything that we don't use ourselves and have proven effective in race/track conditions.

 

A while back I installed a lightweight AGM battery in my GR40ST. I drive the car daily and track it 'hard" at least once a month with this battery installed.

 

I got the setup from HP Autowerks in Santa Barbara.

http://www.hpautowerks.com/

 

HP Autowerks is a high end german tuning shop, but the kit they have for the 1991-2009 BMW M3 is a direct fit for the S197 Mustang/Shelby. The guys at HP are nothing less than first rate.

 

The battery is made by Braille Battery USA:

http://braillebattery.com/

 

The battery/hold-down kit is available here:

http://www.hpashop.com/product.sc?category...mp;productId=45

 

Or you can contact Harold @ (805) 966-3200.

 

It is available with three different batteries. 11.5lb, 15lb, and 21lb and are available with a real carbon fiber wrap (looks cool but not necessary and saves no weight)

 

All three batteries exceed the CCA rating of the stock Ford battery.

 

I'm using the B2015 15lb. battery and have no issues. It took 19lbs. off the nose of the car, verifed by our shipping scale and vehicle scales at the shop. It bolts in using the stock battery clamp and literally took me 5 minutes.

 

It does need to be said you cannot sit in the car with the engine off and listen to the stereo for hours and expect the car the start. That being said it is a great upgrade.

 

Colin Sebern

Griggs Racing

 

 

 

The description of this battery says daily use for "4 cylinders" ? do you just put this in to go to the track???

[AFBLUE]

Diet and exercise can achieve even better results :D

[GR40Freak]

The description of this battery says daily use for "4 cylinders" ? do you just put this in to go to the track???

 

 

I have replaced my stock battery and use the small one everyday. No problems.

 

 

Colin

[zdle]

I have replaced my stock battery and use the small one everyday. No problems.

 

 

Colin

 

Think this will work from the trunk?,,,,,,or is that to much line loss ?

[GR40Freak]

Think this will work from the trunk?,,,,,,or is that to much line loss ?

 

I haven't done it yet.

 

Colin

[GR40Freak]

Diet and exercise can achieve even better results :D

 

Working on that too.. But I'm 6'6".. I'll never be light.

 

Colin

[89Saleen215]

There's also the Dyna-Batt...haven't heard much about them in years...not sure how they stack up.

[SkyDancer]

I don't know.......What's that going to save me? About 1 HP? The usual money spent to HP gain ratio is usually considered to be $25 to $35 / HP. Anything beyond that is considered throwing money away. So $235 / 1 HP ??????

[GR40Freak]

I don't know.......What's that going to save me? About 1 HP? The usual money spent to HP gain ratio is usually considered to be $25 to $35 / HP. Anything beyond that is considered throwing money away. So $235 / 1 HP ??????

 

I'm not quite following you..

 

I'm seeing 19lbs. removed from a location over 20" above the CG of the vehicle. That makes a difference when you are pulling 1.5Gs.

 

In our field.. every little bit helps. Next is to relocate the battery to the rear and to the lowest place possible.

 

Colin

[SkyDancer]

I'm not quite following you..

 

I'm seeing 19lbs. removed from a location over 20" above the CG of the vehicle. That makes a difference when you are pulling 1.5Gs.

 

In our field.. every little bit helps. Next is to relocate the battery to the rear and to the lowest place possible.

 

Colin

 

 

OK....now I'm following you regarding the G-factor. Sorry!

[TurboShelbyGT]

GR40freak,

 

Thank you. You are the first guy I have seen on this site that has any interest in getting rid of useless weight. I thought I was the odd ball, now atleast I have company! We run those batteries too, great battery. The PC680 works great too along with the Dynabat but the warranty on the Dynabat sucks. I'll take 20 pounds of lost weight anytime I can get it.

[greaser]

GR40freak,

 

Thank you. You are the first guy I have seen on this site that has any interest in getting rid of useless weight. I thought I was the odd ball, now atleast I have company! We run those batteries too, great battery. The PC680 works great too along with the Dynabat but the warranty on the Dynabat sucks. I'll take 20 pounds of lost weight anytime I can get it.

 

 

ill take that heavy tank conquest off youre hands

[kahmann]

GR40freak,

 

Thank you. You are the first guy I have seen on this site that has any interest in getting rid of useless weight. I thought I was the odd ball, now atleast I have company! We run those batteries too, great battery. The PC680 works great too along with the Dynabat but the warranty on the Dynabat sucks. I'll take 20 pounds of lost weight anytime I can get it.

Check this thread out from 4/9 and by all means throw your input in: http://www.teamshelby.com/forums/index.php...c=41724&hl=

 

Ken

[MarkGT08]

19 lbs. ? That's it? Hell if that was something I could even notice in my suspension, the handling characteristics of my car would change everytime I took a dump!

[kahmann]

19 lbs. ? That's it? Hell if that was something I could even notice in my suspension, the handling characteristics of my car would change everytime I took a dump!

I'd say you don't track your car very often then. 19 lbs is still 19 lbs less than he had before. Any weight savings at all will only benefit you on the track and save fuel on the street.

 

Ken

[MarkGT08]

I'm not quite following you..

 

I'm seeing 19lbs. removed from a location over 20" above the CG of the vehicle. That makes a difference when you are pulling 1.5Gs.

 

In our field.. every little bit helps. Next is to relocate the battery to the rear and to the lowest place possible.

 

Colin

 

1.5 Gs? I don't think so. Maybe if you slide out sideways and hit something relatively soft

[MarkGT08]

GR40freak,

 

Thank you. You are the first guy I have seen on this site that has any interest in getting rid of useless weight. I thought I was the odd ball, now atleast I have company! We run those batteries too, great battery. The PC680 works great too along with the Dynabat but the warranty on the Dynabat sucks. I'll take 20 pounds of lost weight anytime I can get it.

 

Damn, I wish I live closer to you then. I would help you out with your weight problem by draining 3 gallons of your gasoline into my car.

 

Don't mention it. That's what friends are for!

[GR40Freak]

1.5 Gs? I don't think so. Maybe if you slide out sideways and hit something relatively soft

 

Interesting comment. The facts however are these...

 

1.5G is about average for our GR40 Series cars.

 

http://gr40cars.com/media/videos/07_Hill_Climb.html

 

And that video was taken on a public road during a closed timed event so he was not driving at the limit.

 

We've seen even higher in recent testing.

 

Colin Sebern

Griggs Racing

[JeffIsHereToo]

Damn, I wish I live closer to you then. I would help you out with your weight problem by draining 3 gallons of your gasoline into my car.

 

Don't mention it. That's what friends are for!

 

 

Did you have something to add to the conversation?

[MarkGT08]

Did you have something to add to the conversation?

 

 

Colin, with all due respect to your racing experience which I can't profess to know, here is MY experience as an engineer. I won’t tell you your business, but I will tell you my business. There is a huge difference between sustained Gs and short impulse Gs. I don't know what this G meter is actually computing other than this short impulse response, But you that you are not measuring anything meaningful as far as lateral Gs. What you are doing is called "bouncing" a G meter and it's a misleading instantaneous measurement. There is a measurement called “jerk” (no jokes, please), which is the time derivative of acceleration. What it means is that when an acceleration rate is rapidly changing, the rate change of acceleration makes the instantaneous measure of acceleration (due to detector overshoot) inaccurate to an ordinary G meter. And by the length of time that the meter registered 1.5 Gs, it appears that is exactly what happened there in the video. You aren't really measuring any meaningful lateral Gs when you bounce the meter. I can take a KIA and make a G meter snap to some outrageous number. It's just an impulse response is in not a real world situation. I know about it. I have seen it in aircraft all the time. I can also make a G meter register 100 Gs for a few milliseconds just by dropping it a half inch on a table. Nope, I don't spend much time at the track, but I do spend a lot of time working in Physics, Science and Engineering.

 

If you weighed 200 lbs, then 1.5 G laterally would be exactly the same as if a 300 lb person was sitting on you "sideways". Unless you are the Incredible Hulk, I doubt that you could hold onto the steering wheel, press any pedals, or even stay in your seat without being seriously damaged by your seatbelt. As a matter of fact, you would probably fly into the passengers side door with even force to smash it open or break the glass. Of course that is all assuming that 1.5 G laterally would even be possible on rubber tires at all, which it isn’t. The maximum coefficient of static friction between the tires and the road, given almost perfect conditions is 1.0. It is possible to slightly exceed that if there is some sort of aerodynamic downforce, but not even close to 1.5G. On a banked track, with some additional forced normal to the track surface, the total G force can go higher, but then the lateral component of the G forces still could barely exceed 1 G.

 

Even accelerating forward, 1G of force is the same as 0 - 60 in 2.736 seconds. So without spinning your tires, that is the limit to mechanically driven acceleration. After that the tires break free, and then you are at the mercy of the coefficient of dynamic (sliding) friction which is much lower than static friction. It is possible to accelerate faster than that if you either overpower the tires with about triple the horsepower used during the static friction acceleration and use the little bit of friction that you have left to move forward generating ungodly amounts of burning rubber. Or you can also make the tires stick to the track by doing a burnout like dragsters do to give you additional temporary adhesion beyond the friction component. By the way, all of this only works if all of the cars weight is on the driving wheels during the acceleration, so your front wheels would have to be off the ground during the entire event. You can also try and provide non-mechanical type acceleration by attached a thrust driven means of force such as a rocket or jet engine to the back, and then all bets are off until you get near Mach Speed, when a whole lot of other issues start to happen.

 

I know this stuff. I have even taught this subject to undergraduates. I have degrees in Physics, Aeronautical Engineering and Electrical Engineering. I designed aircraft turbines, airframes, control systems, landing gear and structures for many years while I was a research Scientist for the Air Force. I worked on the Space Shuttle brakes, and have an excellent understanding of frictional forces and G forces. What your meter is reading is misleading, at best.

 

If you want to use your G meter to measuring relative cornering to compare yourself to someone else's performance, that's fine. But I don't take those absolute numbers to mean much of anything.

 

Now, before everyone else piles on and starts giving me crap about all of this, save your breathe. I have attempted to post this information based on MY expereince in this subject. I went through a similar discussion with a bunch or Corvette owners a couple of years ago. And all it ended up being was "science" people versus "but I drive on the track" people and a lot of insulting name-calling. Personally, I am not going to get into a back and forth debate for the next few weeks about the "seat of that pants feel" all over again. If you don't agree with the physics of the situation and insist that your car is a rocket ship with unbelievable performance, go ahead. If you insist that you are experiencing all these Gs in your car, then fine. I'm not going to try and convince you otherwise than through this single post. Anyone who wants to argue the points made here or wants to see the math can just send me an offline message, to avoid cluttering up this forum.

 

Colin, as I said before, I'm sure that your cars and your experience allow you to pull more Gs in your cars than probably 99.999% of the general population, but try pulling those Gs in a circular course and I am sure that you will see a much lower number real number.

 

http://forums.roadandtrack.com/archive/ind...hp/t-33219.html

 

http://en.wikipedia.org/wiki/Jerk_(physics)

[MarkGT08]

Did you have something to add to the conversation?

 

 

Jeff, was my response to Colin Ok? Please let me know.

[JeffIsHereToo]

Jeff, was my response to Colin Ok? Please let me know.

 

 

VERY nice, not a clue if what you wrote means anything, but I'm just here to keep things respectful.

 

Welcome to the forum!

:happy feet:

[MarkGT08]

VERY nice, not a clue if what you wrote means anything, but I'm just here to keep things respectful.

 

Welcome to the forum!

:happy feet:

 

Thanks, my mom always told me to never get the boss mad!

[USBlueStage2]

I'll take the 20lbs. It helps with gross weight, as well as weight distribution. I would focus on the wheels and brakes next for weight reduction - removing 10 lbs from each wheel is like removing 280 lbs from the car (must apply 7:1 ratio due to the fact that the weight is unsprung - at least that's what Porsche engineers say).

 

Its not so much about total HP, its easy to add HP to these cars, but that may not help you get around a track any quicker (at least at track with turns).

 

On "g forces" - here's a list of skid-pad results on a wet track: http://wot.motortrend.com/6534699/one-lap-...cord/index.html.

 

Surprise, AWD GTR was tops at less than 1g. I think the Ford GT topped the skidpad at 1.1 G.

 

Here are some results for "race cars" :

 

1998 Cart car 1,42 G

1998 Indy car 1,38 G

Nascar Chevy 2002 1,12 G

 

But check out the g forces generated in a Formula One car: braking g-forces can be as high as 5 gs. That's one hellavu gorilla on your back - how does the driver not fly right out of the car??

 

John Stapp was subjected to 15 g for 0.6 second and a peak of 22 g during a 19 March 1954 rocket sled test.[11] Value

(or range)

The gyro rotors in Gravity Probe B and the free-floating

proof masses in the TRIAD I navigation satellite[12] 0 g

Moon surface at equator 0.1654 g

Earth surface, sea level–standard 1 g

Saturn V moon rocket just after launch 1.14 g

Space Shuttle, maximum during launch and reentry 3 g

High-g roller coasters[13] 3.5–5 g

Formula One car, maximum under heavy braking 5 g

Apollo 16 on reentry[14] 7.19 g

Typical max. turn in an aerobatic plane or fighter jet 9 g

Maximum for human on a rocket sled 46.2 g

Sprint missile 100 g

Brief human exposure survived in crash[15] >100 g

Shock capability of mechanical

wrist watches[16] 5,000–7,500 g

Rating of electronics built into military artillery shells[17] 15,500 g

9 × 19 Parabellum handgun bullet

(average along the length of the barrel)[18] 31,000 g

9 × 19 Parabellum handgun bullet, peak[19] 190,000 g

 

And last but not least - top fuel dragster - 5.3 gs of straight line acceleration - WOW.

 

Taken from: http://en.wikipedia.org/wiki/G-force

 

Check out the pics of the rocket sled - another big WOW.

[GR40Freak]

MarkGT08,

 

I have an extremely diverse automotive background spanning more than 20 years, including vehicle design, longevity/evaluative testing, fabrication, construction, and list goes on... all of which is for the purpose of competition or performance. I also spent several years working in Engineering at UCSB, so everything you've written, I understand very well.

 

I never stated that the 1.5G was sustained, that particular vehicle was only able to sustain 1.2G at the time of the video. I am aware of the of the difference between sustained and peak measurements.

 

I have a Griggs car, and I drive it hard on the track (GR40ST Infineon Video). I'm in good condition and can't drive very long because... with stock seats (marginal lateral support) even with competition seat belts the effort to stay in the seat is exhausting. Even with race seat I have to wear a neck collar as the muscles in my neck become very tired from both the G forces and the rate at which they come. The car turns very quickly and can change direction very quickly. (I am trying to keep this understandable for everyone who is reading it.)

 

The Griggs GR40 cars can sustain 1.4G in a turn. Will it do that on a Skid pad.. depends... it depends mostly on the tire type, pressure and temperature as well as the Skid pad itself, i.e. surface, temperature, outside factors (dust, oil, water, etc.)

 

Just because the car didn't show that number on a "Skid pad" doesn't mean it doesn't do it.

 

I could go on but.. I have a better idea.

 

I am not an engineer, however Bruce Griggs is. He took a look at this thread and what you have written and sent me the following response:

 

"With all due respect, from one engineer to another, I thought I knew what flying and g loads were about, until I got into an aerobatic aircraft I really had no idea. This is why we demo our cars so often, because no one can understand this kind of performance until they experience it. With that said, I agree with a lot of what the gentleman said, and it is true that peak can be a result of “bounce” but there is much overlooked in the synopsis given.

 

I presume this discussion is a result of the 1.5 gs shown on the Virginia Hill climb video on our website which gets everyone in a tizzy that Griggs Mustangs pull 1.5 gs. Well our data says so, and on some of our more seriously prepared track cars, with similar but softer compound tires and light aerodynamic down force, peaks approaching 1.9 gs are currently reached. This on level moderate speed corners like found at Laguna Seca, and Thunderhill. But all these numbers are meaningless if not used in reference to the environment they were attained, and their relation to other performance data. To us, displaying the G numbers are just to point out to those familiar with real performance that we have something really good. The data we use to value our performance is lap times, but most people won’t understand that.

 

While it is true that rubber is listed in textbooks as having a Friction Coefficient of 1.0, the tires used on this car most likely have a higher Cf. And the surface, state highway has a lower Cf than most quality race tracks, due to the purpose made asphalt for each. But the amount of rubber contacting the ground and how evenly it is loaded during transient moments are the key factors in understanding the reality of High Gs attainable in a modified production street car.

 

First let’s consider skid pad numbers. Every skid pad I have found in California either has an inconsistent surface or is not level , and all seem to be very bumpy. Certain magazines test on airports on concrete or asphalt that is seldom used and therefore not always well maintained with poor grip. I have seen very stiffly sprung cars bounce their way to high G numbers because they bounce up, lose some grip which allows them to accelerate outward momentarily, and then when they come back down they ‘jerk’ back in toward the center of the circle. The driver has to constantly and quickly correct with steering and throttle to stay on the 50 or 100 foot radius circle. The data logger shows high peak Gs, but a more compliant chassis can follow on the same day, and circle the pad in a shorter time therefore averaging higher Gs, yet register lower peak numbers as all the bumps were absorbed in the supple suspension. So the only real way a skid pad can be used is if it is level, smooth and has a consistent surface like that that we are actually going to drive on.

 

We don’t race on Skid pads. In the arena of performance driving, be it on a race track or a cloverleaf, the car is rarely in a constant steady state of turn on a constant radius. In a real world turn the corner is parabolic, and so should be the lateral acceleration curve. If the car is working well, the curve will be smooth and the numbers high. The car is decelerated as far as possible into the corner and then accelerated out of the corner as early as possible. The polar graph of 2D acceleration, or “friction circle” as SAE calls it really tells all. If the graph is smooth all the way to peak Gs, then Jerk is a minimal factor, if at all. This is the case in our data which is real word and not journalist generated in some obscure vacant out of the way place.

 

If one notices in the video, the driver does little correction as the G numbers climb approaching the apex and transitioning to throttle where they smoothly decline as the corner is exited. This is substantiated by watching another video on our website of John Griggs ‘98 Cobra convertible at the Ferrari Club VC Hill climb. (King of Hill 2008). While viewing this video you can watch the key fob as it swings far past 45 degrees, (the angle that would equal 1.0g) and although it bounces, it is minimal and may be due to the air turbulence in the open cockpit. If you measure the angle and do the trig you can figure the G loading. But the lack of steering correction demanded of the driver means that both of these cars are being driven without drama, easily under control at very high lateral accelerations, beyond what most any other similar weighted sports car can do, especially with such ease. This is what experienced drivers notice about these videos, and what they extol once they get a chance to drive a GR40.

 

Next we need to understand the tire’s behavior. There are 4 of them 11” wide, and have an elastic structure. They have a carcass that has to be understood and held at proper camber angles to the ground in order to maintain maximum contact area. This the GR40 chassis does with camber gain designed for what these tires need. The tires on the car are Hoosier R compound DOT tires, for their type-- the best in the world in holding their shape under lateral load. But still, even they can be overloaded and abused on a poor chassis. (We also use Toyo RA1s and R888s, almost as good on track but more streetable). When a tire is overloaded its tread distorts, losing contact area. At the wrong pressure, or at the wrong camber angle, less contact occurs as well, yielding lowered Gs. The reason the GR40 achieves such high lateral acceleration is that all 4 tires are fully utilized and their carcasses are not distorted under load, because the chassis, even at such high loads does not over load any one tire, but keeps them all in relative balance. To prevent scrubbing the tires against each other, steering geometry has to be perfect, and track change has to be nil. Bump steer has to be correct. Kingpin axis to Caster relationships have to be correct. And weight has to be transferred as smoothly as possible as the corner is negotiated. This requires consistent geometry and a linear f/r roll couple distribution along with correct low speed damping throughout the process. Surface irregularities need to be accommodated with minimal distortion to the tire’s carcass so as to maintain consistent loading and maximum contact which requires correct and consistent high speed damping.

 

The tire’s tread compound and carcass have an optimum operational temperature where its coefficient of friction and its adhesive capability peak. This is usually at about 180-200F. Controlling these is a result of chassis and driver. In the videos, the highest Gs are generated late in the run, as the tires reached closer to their peak operating temperature and optimum pressure.

 

Now, regarding the 300 pound gorilla pressing on you, that is what it kind of feels like. Without seats with high lateral support it is impossible to drive well, at least for very long. I’m 6’4” weigh 260lbs, and in stock seats the car does try to toss me out. Shoulder harness burns the neck, I get bruises on my elbow and sides of my knees from bracing myself, and it is no fun. It is not possible to drive well at the limit spending most of your energy holding yourself up and in your seat. That is why we have high lateral support seats that do that. Although the lateral pressure against the seat is great, it is momentary as the data reflects on the4video (although the neck gets a workout). In a real comfortable well supported race seat, this kind of performance becomes an unbelievable joy.

 

So Colin, just say they make 1.4gs like I do. That still knocks off all the competition in as delivered street legal open track cars."

 

 

Mark, I imagine as an engineer with your background its easy for you to shoot things like this down, but the that fact is the car IS a rocket ship and the performance IS unbelievable. . Once you experience it yourself you will agree and probably get out of the car shocked, wondering how it did what it did. And yes the hardest part.. is staying in the seat.

 

Colin Sebern

Griggs Racing

[Chill]

Colin,

 

All of this is interesting but......I just want the Griggs suspension!!

 

(:

[kahmann]

My head hurts.