weight distribution - some measurements...

[Michael]

Well, amidst the chaos of the apparently failed rod bearing, I got a chance to weigh the "set-back rat" on a set of four digital scales. Here are the numbers (all are in lbs):

 

with no occupants:

 

left front: 718 right front: 690

left rear: 643 right rear: 674

 

total: 2725

 

 

with the driver:

 

777 680

727 723

 

That comes out to about 51% front/49% rear. I was hoping for something like 47/53. However, the car came out 100-200 lbs lighter than I expected. This is a '78 280Z with about 150 lbs of roll cage and other steel inforcements, aluminum (currently empty) fuel cell, 90% of the interior missing, no dash, no HVAC system, but all metal body panels installed, and technically in running condition. The most forward right-side spark plug is ~8" behind the wheel centerline.

 

The conclusion is that 1) big blocks are really really heavy, and 2) decent weight distribution is still possible, but requires elaborate revisions to the stock vehicle.

[Modern Motorsports Ltd]

Hmm, what ideas have you got for changing the distribution? Got some detailed pics of engine bay on line?

 

-where is your battery and what size/weight?

What type of radiator do you have? What type/weight of wheels? Sounds like you've done a lot already for weight efforts. Aluminum heads? seen some GM BB alum. heads for $1500US complete on sale at Sallee GM

[Michael]

Some more details...

 

The battery is in the rear, next to where the fuel tank vapor canister normally sits.

 

The radiator is a Griffin 28"x19" (frame rails notched to fit the wide radiator).

 

Suspension is completely stock.

 

The motor is all cast iron, except for block hugger headers and aluminum intake. For big blocks, aluminum heads are claimed to save 70 lbs. I looked at the GMPP aluminum heads - they are one of the options, along with Edelbrock and Brodix, among the oval port choices. Do any of the big block drivers have a particular recommendation?

[Modern Motorsports Ltd]

Got any pics of your setup online? I'd like to see the 'entry' to your radiator frontal area as well;-)

 

Here's a URL to a v. good (like griffin, their norm is Nascar quality/issue) water pump supplier, stewart components. I feel their pump is a large part of my easy running of 87 octane in my 9.4:1 setup along w/ the aluminum heads. http://www.stewartcomponents.com/chevyS2.htm

 

now for my 'weigh-in':

Here's my stats from a weigh-in at the Shasta meet this summer with certified scales and numerous witnesses, with my car complete with stock interior but no spare (no good to my 5 lug 13" brake/s/rims) and 7/8's fuel (~125 lbs)both with and without driver just prior to an autox event:

 

viewed from top to bottom/left to right (scale techy enthused as many Z's shy away from scales)

without driver:

FL 693 FR 793

RL771 RR 659

Total weight: 2916 lbs

Front: 1486 (51%)

Rear: 1430 (49%)

 

now w/ me (190lbs in the car, and rocked twice by scale technician as he was in disbelief at %'s and got out his notepad:-)

758 792

850 702

 

total: 3102

Front: 1550 lbs 50.0%

Rear: 1552 lbs 50.0%

 

Any spare or gear at all gives it a rear weight bias:-) Prior to moving my battery and swapping from iron heads it was still only 51/49 so a budget effort can still make for fine handling.

[Mikelly]

You guys both nailed the formula for building a great conversion! The non-believers will be sick when they read those numbers! I gotta get some scales!

 

Michael, I'm impressed with those numbers based on a big block buildup! Super impressive!

 

Mike

 

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"I will not be a spectator in the sport of life!"

mjk

[Guest RON JONES]

I've always had good luck with DART heads.I'm not to sure they make an oval port.I know a guy that is running a set of brodix oval ports and is very happy with them.

[Guest RON JONES]

Yep,DART makes an oval port.Here is a link http://www.dartheads.com/

 

 

 

[This message has been edited by RON JONES (edited September 24, 2000).]

[Michael]

Folks,

 

OK, here it is - pictures of my car: http://members.home.net/pparaska/MichaelOlsZ.htm

 

A big huge thanks to Pete Paraska for hosting my "web page"!

 

I apologize for the sloppy photography - hopefully I'll have better images soon. The last photo sort-of shows how the engine is installed, but the rear 1/3rd of the engine sits under the windshield valence panel, obscuring the view. If you look closely, you can see the Griffin radiator angled forward.

 

With the hood closed, the air cleaner just barely sticks out. Big blocks are tall. I had to either put up with the air cleaner sticking out, or the oil sump hanging too far below the frame rails.

 

Contrary to what the label beneath my user name says, I now live in Dayton, Ohio. Which means that racing season is drawing to a close. It won't be until next spring that I'll get a chance to run the numbers on the car at the track. But, it will take at least that long to fix the rod knock, figure out how to upgrade the stock half shafts, sort out the wiring (I threw away the 280Z electrical system and started from scratch), sand out the rust and get the car painted, etc., etc.

 

Currently there is no room for the windshield wiper assembly, the dash won't fit because of lateral roll cage bar that's in the way, the window cranks and arm don't clear the X-bars in the door, and the fuel cell sits right behind the rear strut towers. But these are "minor problems", compared to what had to be taken care of us to get this far

[Drax240z]

Holy crap, can you say chassis stiffness? No doubt you need it with that much torque.

 

I wonder about having 14" x 6" wheels on something like that... have you ever managed to move the car without wheelspin? Hehe.

 

Looks like you have lots of work ahead of you this winter... Good luck.

 

 

 

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"THE STREETS WILL FLOW WITH THE OIL OF THE NON-BELIEVERS"

 

Drax240z

1972 240z - L28TURBO transplant on the way!

http://members.xoom.com/r_lewis/datsun.html