Lightweight

[Bob Tucker]

Isnt the Elise made from bonded aluminium?

Anyone know what adhesive Lotus used?

[Guest ScotMac]

Mark, one more thing i forgot to mention. Welding aluminum substantially decreases its strength, as i am sure you know. For bicycles, they usually heat treat it after welding, to restore the strength. I would guess that heat treating the entire chassis is not an option for most l/w'ers ($$$$). Note, the amount of reduction in strength does vary per alloy of aluminum. another reason why we need to get the exact aluminum alloy from RH...

[Guest docter fox]

Scotmac, although the common english t5 box is inferior, isn't that what's used on the sierra cosworth? if so it can't be that weak surely?

[Guest ScotMac]

Here is some interesting info on aluminum alloys and issues w/ welding them:

 

http://www.weldingengineer.com/Aluminum_.htm

[Guest ScotMac]

Yes Doc, i believe the cossie t5 is much stronger than the typical stock type9, however i do not believe it is a full WC t5. Here is a (adhoc) heirarchy in terms of strength:

 

stock type9 (< 200 ft/lbs???, don't know exact rating)

cossie/I4 t5 (240 ft/lbs)

Non-WC pre-85 (265 ft/lbs)

early-WC t5 (85-89) (265 ft/lbs)

90-93 t5 (300 ft/lbs)

93 cobra t5 (310 ft/lbs)

 

BTW, tho Non-World-Class pre-85 t5's had the same torque rating as the early WC (85-89), it had substantial strength and reliability issues due to bronze synchros and no bearings under the gears.

 

Here is a quote about the I4 t5 :

 

" Ford also used the T-5 in 2.3L cars through the years. While the 4 cylinder T-5 may appear to be the same, they are not. Most 4 cylinder T-5s received a 3.97 gear set with a .79 overdrive and small input pilot bearing shaft. Four cylinder T-5's should not be used behind a V-8, even when the pilot bearing id is decreased to match. Simply put, they will not hold up. Torque rating ~240ft/lbs."

 

I plan to race my L/W, so if i can get a substantially stronger t5 for a pretty good price (cobra at $695)....

[Guest CaLviNx]

Hi

 

With regards to heat treating aliminium,although I have a tig set I was looking at using "lumi-weld" a type of brazing at a low working temperature of 732° F (392° C) and mostly avoid having to heat treat the job after welding it.

 

Also being near the Oil capital of europe "Aberdeen" large ovens & heatable autoclaves are common bits of kit, if you know who to talk to.

 

I was reading it in some old brochure of robin hoods when the lightweight was first touted to the world about the gearboxes it would take, I will see if I can dig it out.

 

Regards

 

Mark

[Longboarder]

2 wheel drive Cossie BW T5 is good for 450-500 bhp (depending on what you read), a standard Type nine only 200 bhp.

If the engine is producing 450 at 5252rpm that figure translates directly into torque.

 

Nigel

[Guest ScotMac]

Nigel, i think we are basing our numbers on totally different things. All my numbers from the early t5's onward are quite simply the manufacture (borg warner) spec's for torque. Not what people have got out of them. In addition to the link i prevously published on this (http://www.moderndriveline.com/Technical_Bits/t5_history.htm), you can also see the EXACT same specs on the following page : http://carcraft.com/techarticles/116_0404_gear/.

 

Note, the I4 t5 was rated slightly lower than the early t5's (~240 vs 265), because of the smaller input shaft and pilot bearing.

 

Now, my understanding is that the cossie t5 is the I4 based t5. I guess that cossie/ford couldve mod'd the base t5 (265ft/lbs at that time) to handle a lot more hp. But why? The original cossworth sierra RS put out 204 hp ('86) and 224 hp ('87) from a 2.0 litre I4...

[Guest ScotMac]

Mark, that "lumi-weld"ing looks pretty interesting...if it does what they claim. Here are some specs on a new version of it, called hts-2000, that claims to be substantially improved from the already very strong original lum[ia]weld:

 

http://www.newtechnologyproducts.net/more_info.htm

 

Note, to summarize, the report says that it has the following physical properties:

 

Tensile: 45,900 PSI

Therm. Exp.: 15.2 x 10- 6in./in./F°

Elongation: 10% in 2 inches

Elec. Cond: 26 (% of copper std.)

Impact: 43 Ft. lbs (charpy)

S.P. Grav.: 6.6

Shear: 31,000 PSI

Weight: 0.24 lbs/cu. in.

Melting Point: 717°- 737°

Rockwell: 48

 

Note that amazing shear, impact, and tensile strength, and a melting point 400-500 degrees less than aluminum, so none of the typical burn-thru problems of aluminum welding, nor the weakening problems (as Mark pointed out). And it is supposed to be very easy to "weld". Hmmm ... don't know if i can believe their numbers, but if they are true, i might have to re-think my bonding strategy...

[Guest CaLviNx]

Hi

 

Scot I have used my "luniweld" kit on at least three occasions with one

being in a stress loading area and another under the pressure of an A/C systems high pressure side of the circuit, and they are all still working perfect to this day. Until I used Lumiweld/Easyweld I was a bit sceptical about it untill I actually used it, I am now a convert.

 

 

 

(EDIT)

 

I just went to the webpage scotmac listed for the brazing rods, and I "attempted" to buy but when the shipping cost nearly matched the cost of the "starter" pack I promptly cancelled the order. so buyer beware a mighty good product but not to international customers.

 

(EDIT)

 

 

Regards

[Guest ady]

Mark, are we thinking of the same product? I have used lumi-weld before to repair ali door skins, and although it works very well in a non structual situation it is a brazing product. These are not acceptable for bodywork repairs, so I would think the SVA man wouldnt accept it as a condtruction method. Also i found it to be more brile than the bace aluminiun (unknown grade on 45 year old door skin). I would expect it to crack on a joint that was trying to move.

[Guest ScotMac]

They claim that though it is a brazing method, it somehow molecularly bonds w/ the alluminum alloy, thus giving you a "weld" stronger than a normal aluminum weld (properties of a normal weld, w/out the heat).

[Guest CaLviNx]

Hi

 

Ady I suppose we are talking about the same product, the one I have used is very similar to the one listed by ScotMac, and I have certainly used it on structural suspension components that I know for a fact are still to this day bearing torsional loads with no ill effects.

 

So if its listed as not being strong enough, to allow use on a structural component I for one beg to differ, and when used in the context of "certain" sections of a lightweight chassis, the lumi-weld method of braizing aliminium would only be employed as a "belt & braces" method along with riviting & bonding not as a replacement to.

 

Regards

 

Mark

[Guest ScotMac]

I am not sure i believe their hype, but if you look on their website, they have a guy in sacramento claiming that he has fixed blowers, manifolds, and engine heads w/ it.

 

Also note, that these "newtechnology" guys (marketing the new hts-2000 version of lumaweld) claim that the original lumaweld had an elasticity/elongation of about 3% over 2", vs 10% for hts-2000...supposedly making it less brittle than the original.

 

BTW, i hear the video is pretty amazing...but i can't get it to play. Anyone else have any luck w/ it????

[Guest ScotMac]

Mark, your point about "certain" sections is that you feel it is too brittle for the flexing that many sections of chassy would require???