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heavy85

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Posts posted by heavy85

    Mechanical Engineers? Modifying JTR Mounts for More Offset/Math Calc.

    in Gen I & II Chevy V8 Tech Board

    Posted

    Regarding engine loads and load paths this raises a question. (Ron, I’m borrowing from your post which I think I’m talking about the same thing?)

     

     

    With the engine mounted to the cross member, all vertical loads, engine weight, etc, are transmitted through the cross member, into the lower frame rail, through the fender apron/strut tower to the upper rail/strut tower where the weight of the car and engine rest on the upper spring perch.

     

    Lateral loads, such as in a corner, with the engine mounted on the cross member, the “lateral weightâ€, or lateral load, of the engine is now transferring directly through the cross member directly to the lower control arms, i.e. the chassis/frame rails aren't seeing any real lateral loads from the engine, (except from the tranny mount of course).

     

    Now if the engine was mounted directly to the frame rails, the vertical load path is slightly altered as the engine weight is now being induced to the lower frame rail further rearward. To a MUCH larger degree is the fact that now the lower frame rail is also seeing the lateral loads of the engine through the lower frame rail to the cross member then on into the lower control arm, i.e. asking the lower frame rails to take on a LOT more forces laterally that it never used to see with the engine mounted to the cross member. Is that an issue for an autocross/street car regarding chassis flex and controlling load paths through the chassis? I’m not sure, and I guess it would depend on how serious the approach is to such a track car and also how sensitive the driver is to such things and how much comprise he/she is willing to live with.

    Granted, this scenario did not take into account any chassis strengthening mods and is all theory.

     

    That's exactly why I did this to mount the LS1. Trying to connecting the mass to the tires as directly as possible ...

     

    P10100801.JPG

     

    Cameron

    Go tube chassis or keep unibody for my triumph?

    in Brakes, Wheels, Suspension and Chassis

    Posted

    If you are planning to autocross the car, you will at least need a cage,

     

    Uh what???? I race with a guy who rolled his FSP LeCar (Renault) during an autox. To fix it he actually cut the roof off and replaced it with another one and at the same time REMOVED his rollbar since it was 'dead weight'. I can't imagine why you would "need" a rollcage for autox unless you are trying to stiffen the chassis.

     

    Cameron

    Braided fuel line

    in Fuel Delivery

    Posted

    I used Aeroquip teflon hose with the steel braid. It's the industrial stuff but rated for fuel and a lot higher pressure than the fuel system will ever produce. It uses AN compatible (37 deg flare ... JIC style) re-usable ends. It was also cheaper than Earls at least around here at somewhere between 6 and 7 $/ft if I remember but dont quote me on that. It's only had gas in it for a couple weeks but given it's solid teflon I dont expect any problems. The only reason I could think they dont market this as fuel hose is the kinkability mentioned above. It's marketed as brake hose I believe.

     

    PS: I thought the NHRA rule was not more than 2' of rubber hose but steel braided was not restricted?

     

    Cameron

    Under chassis brace

    in Brakes, Wheels, Suspension and Chassis

    Posted

    Hey Heavy85....If Im understanding this correctly...the cross brace is bolted to the transmission tunnel for quick removal? Nice work!

     

    If you have run it yet.... did it make a big difference?

     

    The second pic is half finished but if you look at the first one it actually bolts to the tunnel with two bolts per side PLUS it bolts to the tubes that go out to the SFC also with two bolts per side. It's really a bit of a pain to install as you have to angle it up past the tubes, push it over, and kind of wiggle it up in there. You have to do this because the tubes to the SFC are actually narrower than the top of the mount so you can't just raise it into place. Have not run it yet but it will be hard to tell because I added a bunch of other chassis improvements at the same time + the LS1/T56. I'll know more this Spring when it's driving.

     

    Thanks for the compliments guys.

    Cameron

    Under chassis brace

    in Brakes, Wheels, Suspension and Chassis

    Posted

    That's very nice, I like the idea, I guess if it was to be made out of aluminum, it wouldn't weight to much. Do you have an aproximation of how much your's weight???

     

    Thanks.

     

    It's made out of 14 and 16 gauge plate so it doesn't weigh much. I would say < 5 lbs. Yeah it took a long time to fabricate. Heaviest part is the tubes that tie over to the SFC and that's just because I used what I had (1x2x.083) instead of getting thinner wall since I have to mail order it.

     

    Cameron

    Under chassis brace

    in Brakes, Wheels, Suspension and Chassis

    Posted

    The Z tunnel is super weak. There is no bracing of the tunnel on my 240 at all. The trans mount doesn't go all the way around the tunnel circumferentially and doesn't attach to the frame rails or anything else. I think a lot could be done to strengthen the underside of the car by attaching the frame rails or better yet subframe connectors with a big X shaped structure under the car. This would lessen the vertical and horizontal flexing of the center of the car. The problem seems to be the exhaust is in the way...

     

    That's why I did this for my tranny mount

     

    P10100385.JPG

     

    Here's an early shot not yet complete but installed

     

    P10100441.JPG

     

    Cameron

    Contact patch, weight, and lap times?

    in Brakes, Wheels, Suspension and Chassis

    Posted

    The 1.5" ride height difference would be crucial to me, given all the other factors you have mentioned. Not only for the lower C of G but the potential aero benefits, something a lot of S30 punters don't seem to pay much attention to :)

     

    This seems to be an American thing. Watching the European and Auz and they seems to be really into the aero stuff. Lots of wings and little dodads everywhere.

     

    Cameron

    Final started chassis stiffening ...

    in Brakes, Wheels, Suspension and Chassis

    Posted

    It's been almost a year since the last update so now I'm done with the front end ...

     

    Connecting rockers to upper frame horn and to SFC and a little rust repair (the shark in the middle).

     

    P1010077.JPG

     

    And the finished k-member / engine mounts and strut tower to firewall bars (although a little hard to see in the light). With a combination of the k-member and the SFC to rocker bars it really makes for a nice straight way to distribute input loads (from suspension into crossmember) into the main structure.

     

    P10100801.JPG

     

    And the money shot. It's now running.

     

    P10100861.JPG

     

    Now that the front is about done I'm mostly happy but would probably do something different with the SFC next time. Now time for the back-end. Since everything is so much closer relatively it already seems worlds better than the front. I'm at least adding a harness bar and eventually a rollbar but otherwise nothing is really coming to me yet.

     

    Cameron

    Contact patch, weight, and lap times?

    in Brakes, Wheels, Suspension and Chassis

    Posted

    Cary where do you get bias ply slicks for much less than 1000 to 1300 per set? I would love to run full slicks but usually just go with victor racers. They are a pertty good value for track days.

     

    As for the class issue, I assure you there is no class at all when this group is at the track. :D

     

    http://jbracingtires.net/index.htm I got a set of Hoosiers for $75 per tire. These were 15" x 9.5" x I think 23.5 but can't remember and am too lazy to go look. They were used once in practice at the run-offs and had 100% tread left. I'm not kidding as they were coated in a thick layer of rubber. Once scraped off the molding marks were still there. I could not have been happier with them.

     

    Cameron

    Sectioning struts for Koni 8610-1437race insert

    in Brakes, Wheels, Suspension and Chassis

    Posted

    I personally would buy the struts first and measure before you weld them together. My '72 struts are SO tight that I had to grind the paint and the raised stamped part number off the strut and grind the inside of the strut housing. This was just to get them installed even before sectioning so my point is you have to be REAL straight when you weld them back together or you'll be fighting to get them in. I installed a strut to align the pieces then clamped two pieces of angle iron around the housing. Pulled the strut out, tacked, reinserted strut, make any adjustments. It's just such a tight fit you have to be real precise. I know the later struts are bigger but I dont know if the '74 (assuming from your screen name) uses the smaller or bigger tubes.

     

    I ended up taking ~2" out of both the front and the rear. Then measured the length of the required spacer and cut to fit.

     

    Cameron

    COMPLETE Re-Wire Of 240Z / LS1 / T56

    in Ignition and Electrical

    Posted

    I did this over the last 6 months but I started with a cut-up Z harness (35 years of hacks does that) plus an f-body engine harness. I ended up using the f-body harness and fuse block for the engine power / starter relay / ignition relay. Seems you already have a complete stand-alone harness for the LS. How many other circuits depends on how you wire it really. For example will all the gauges be on one circuit? Power to the low power side of relays on one circuit? Power to starter relay? Power to ignition relay? Power to fan relay? Reduntant left and right separate headlight relays? Etc. T56 back-up switch requires power into the ECM for it to work. F-body fuel tank (if your using it) requires power to the pressure sensor which is used for the evap system. In addition to the engine fuse/relay block I have a generic 10 fuse block, a fan relay, and two headlight relays. That's it and I'm out of fuses and need more for the wideband, additional gauges, fuel tank pressure sensor, etc. I've tried to avoid splicing a bunch of stuff together so the fuses get used up real fast. Need to decide what you will be splicing together to really say. I also have the most stripped down possible configuration with no horn (shh dont tell anyone), no wipers, no heater or blower just basics to make it marginably streetable (lights, brakes, flasher, turn signals, gauges, power outlet for G-tech).

     

    If I had to do it again I think I would have just gone with a Painless or equivalent or at least used some type of either screw terminal fuseblock (if they exist) or a terminal strip to be able to easily splice multiple circuits together. I dont really like twisting several wires together, solder, wrap and would rather use terminals only so I can easily see the connections and are not buried in a harness somewhere.

     

    Cameron

    Baby on the way!

    in Non Tech Board

    Posted

    Congrats on the kid. My four grow faster than I can keep up. My three year olds favorite tool is the cordless impact ... the 9.6V obviously ... he will have to wait a few months for the 18V. Get him a pair of earmuffs so he can be in the garage when you are using loud tools and to use at the racetrack. Sorry no help on the nursery. Our kids slept with us the first year (or three). Makes night time easy for daddy as you're about useless anyway while their nursing.

    Driveshaft Safety Loop

    in Drivetrain

    Posted

    Don't you watch Mythbusters!?

     

     

    "They decided to slow car down to 15mph. This plan was successful -- the driveshaft hit the hole square-on and popped the car up about 1-2 feet, driving the driveshaft up through the trunk. It wasn't particularly dramatic, and not nearly enough to qualify as "pole vaulting."

     

    OK so maybe it wont 'launch' you but your day would still suck.

     

    Cameron

    Maxi-fuse fusible link upgrade

    in Ignition and Electrical

    Posted

    Cameron - on the '77 (and possibly other models - I haven't studied the wiring specifically on those) the fusible links are for:

    1) Alternator output (then connected to battery and the other 3 fusible links)

    2) ECU (oversize 6-way connector @ steering column), and ignition relay

    3) Combo switch

    4) Ignition switch

     

    Thanks for the info. On the donor '02 Z28 the alternator went unfused to the battery which is what I'm planning. The ECU is fused, I'm not using the combo switch (no wipers and headlights are on a fused toggle switch/relay), and I'm also not using the ignition switch (ignition is on a fused toggle switch/relay). So I'm still thinking there is no need for one anywhere. Again the only thing not fused is the alternator output which was not fused on the Camaro either and the very short wire from the distribution stud to the fuse block. I think I'm covered but would be interested if anyone thinks I'm missing something.

     

    Thanks

    Cameron

    Driveshaft Safety Loop

    in Drivetrain

    Posted

    Kind of depends on your set-up as well. The rules above say near the front probably because if the car is rolling the driveshaft is spinning. If you lose the rear u-joint you can simple put it in neutral and it will stop spinning. Also depends on how it's joined. For example my old Datsun comp 5-speed used a bolt-on driveshaft at either end where the T56 used a slip in front. On the datsun tranny your screwed either way but for the T56 if you lose the back end the driveshaft will simply fall out. If you lose the front it will flail everywhere and if your luck hit the ground and launch you. In this situation you definitely want it near the front and I would consider making it large enough so that the driveshaft could slip out if the rear u-joint failed. That's just my initial thoughts as I have yet to install one. More discussion is welcomed as I'm about to this point in my build.

     

    Cameron

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