Chassis and suspension geometry

Pete · Post by **Pete** » Fri Feb 05, 10 9:28 am

Bob on, Blue.

I had the '69 Baracuda weighted with a 440/500 BB in it, 6 point cage, and chassis connectors, Glass Hood, Glass fenders, Steel inner fenders, everything else stock (including heavy rear bench) and it was 3200lbs.

Nick Woods '70 RR was 3400lbs as a guide.

Loosing weight is hard (says he staring at his increasing waistline...)

Ivor · Post by **Ivor** » Fri Feb 05, 10 9:54 am

Thanks for the input guys, this is good stuff, I've only had one A body and that was pretty much stock, so a lot of this is guesswork at the moment, so I'll bow to those of you with a whole lot more experience than me.

I've been working out how to "add lightness" as Colin Chapman used to say and there's an awful lot coming off the car, even the entire front K member and all the stock front suspension is being junked, the entire front end is in glass, but I'm really guessing the weight of these things, so I could be way off.

Once I start the big strip I'll weigh everything, the stock car weighs 2,900 lbs, so I've got 700lbs to lose...

I've bought a set of hole saws...

Pete · Post by **Pete** » Fri Feb 05, 10 10:24 am

Ivor wrote: ..once I start the big strip I'll weigh everything, the stock car weighs 2,900 lbs, so I've got 700lbs to lose...

And you will be putting a lot of weight back IN - subframe connectors, Heavy engine, Cage (+100lbs), brakes that work rather than 9" drums which are light, blah blah blah...........

Ivor · Post by **Ivor** » Fri Feb 05, 10 10:45 am

I had managed to work that one out Pete!

Pete · Post by **Pete** » Fri Feb 05, 10 11:09 am

Ivor wrote:I had managed to work that one out Pete!

I'm not sure you have

2900 + 200 (engine) + 100 (Cage) + 100 (subframe + suspension) = 3300

Target weight = 2200.

3300 - 2200 = 1100

Ivor · Post by **Ivor** » Fri Feb 05, 10 11:21 am

Pete, I think you may be under the impression I have "learning difficulties".

Perhaps I should have said 700lbs total, but thank you for spelling it out for me!

Pete · Post by **Pete** » Fri Feb 05, 10 11:37 am

No, I don't think you have THOSE difficulties.

I was just pointing out (respectfully) that maybe you were over-promising and under-delivering

In all seriousness, it is so hard to get the weight down on a road legal car; so the remedy maybe more power

Just make sure (unlike me) that you get the weight distribution right. Again, this is very hard in a BB "A" body, but I am sure you are up to the task....

Cannonball · Post by **Cannonball** » Fri Feb 05, 10 11:39 am

now i would not put ivor in the dummy catagory i think he might surprise us all, i know for sure the blue 69 coronet full b body weighs in at 2,700 so i reckon that 2,500 is atainable in that early barracuda,
and i also reckon that heavier figures get banded about somtimes on the drag race issue to make its performance look more credible,
the size dont matter they are just bigger empty boxes,

Pete · Post by **Pete** » Fri Feb 05, 10 11:42 am

Does that mean that the Brutus mobile really weighs 3200lbs???

Pete · Post by **Pete** » Fri Feb 05, 10 11:45 am

I also think that whilst the "bigger empty box" may weigh slightly more, the bigger box makes a big difference on stability - i.e. wheelbase in particular; so there are many other factors here...........

Cannonball · Post by **Cannonball** » Fri Feb 05, 10 11:57 am

Pete wrote:I also think that whilst the "bigger empty box" may weigh slightly more, the bigger box makes a big difference on stability - i.e. wheelbase in particular; so there are many other factors here...........

yep now that i agree with,
i think dave b, has seen some off this with his gtx versus his white duster that he built, dont think he was to happy with the drive off the duster at 10.3 yet has no worries in the gtx at 9.8,

the bigger car does seem more stable but that is on regular suspension etc, i am sure the size off car would not be an issue with a pro setup from the likes of webster and robinson etc,

botty ray had a leaf sprung dart that went 11.7s and his rusty ky jelled sheriffs badge used to twitch,
then he bought my old backhalved dart and his 1st pass was a 10.0zero
and his badge was intact no smearing,
now i know for sure he has little balls and it was only because the car drives so well, if some one could have told him nr the top end hey botty your gonna run a 10.00 he would have got off the throttle and Bananarama! himself in reality i think he thought he was on for a 12 breakin pass it was so stable,
i dont think at our level you can beat a proper built backhalved car,

Pete · Post by **Pete** » Fri Feb 05, 10 12:03 pm

Totally agree (though I have no personal knowledge of Ray's botty)

The killer is that a back-halved car is not really at home on the street.....

So, you have to set your goal with the restrictions (street driven, etc) and work to them.

Cannonball · Post by **Cannonball** » Fri Feb 05, 10 12:24 pm

Pete wrote:Totally agree (though I have no personal knowledge of Ray's botty)

The killer is that a back-halved car is not really at home on the street.....

So, you have to set your goal with the restrictions (street driven, etc) and work to them.

very true peter,

but i have never really understood the racecar/streetcar thing, one hurts the other,

fast streetcar and comfort, megafast racecar and trailor simple,s,

Pete · Post by **Pete** » Fri Feb 05, 10 12:31 pm

Agreed IF:

You have the SPACE
You have the TIME
You have the MONEY

And its THAT important to you.

This is why people make street cars go fast at the track...

Ivor · Post by **Ivor** » Fri Feb 05, 10 12:31 pm

Pete no offence taken at all, I really do value your input and particularly the point about stability which Duncan has illustrated very well with reference to the back halved Dart and Ray's chocolate starfish

This is a subject that I'm looking at very closely, the car is planned to be very much race first, street second, just because I want to, no other reason... and a real nostalgia build, but I don't think that means it has to be unstable...or slow!