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Re: MD's Racer-The Flying Brick

Posted: Fri Oct 24, 2008 8:58 am
by ar4me
Visual effect - lens on camera distorted. Front is about -3.8 if I recall. Why -0.5 at the back? Hardly worth the trouble of modifying the Dedion for that, or is that just what the stock Dedion was?
Jes

Re: MD's Racer-The Flying Brick

Posted: Fri Oct 24, 2008 9:03 am
by kevin
MD , the white Giulietta with rear wing on had a problem when Rory cut the dedion. He found he could not turn the wheels as the CV's had jammed. I mentioned this in another post but no one else has had this problem. Maybe his car is that much lower than every one elses. point of thought. Its definately not a power thing that broke it.
Im sure clutch housing was fractured before you did new prop conversion but broke only now. Once you have new BM coupling on rear you are garanteed of no shock waves. Ask Fernando, his coupling just broke on front which resulted in snapped crank.
Basically you are going back to Alfa design but with propper couplings.

Re: MD's Racer-The Flying Brick

Posted: Fri Oct 24, 2008 9:10 am
by Zamani
Jes,

-0.5 is stock I think. I didn't do anything to it...yet. But I would like -2.

Re: MD's Racer-The Flying Brick

Posted: Fri Oct 24, 2008 11:46 pm
by MD
Thanks for the feedback. It's all interesting stuff.
My car's rear end numbers are just -2*.
Zamani,the 0.5* is factory.
Kev.I agree that the clutch housing could have been fractured before the install but we did not notice it. The new one has been crack tested but for budget racing, how much bucks can one spend to ensure everything is absolutely perfect beforehand. You can't. Anyhow if you have a look at typical Alfa castings of anything, there are imperfections all over the place. I originally thought that my sump had a crack in it but on close inspection, it was just a casting line so it can be a hard call to sort the wheat out from the chaff sometimes.

Tried desperately to source a second transaxle with more suitable ratios to instal while we had it out but it hasn't been possible owing to the time frames being too tight so we just made sure the original one is sound and stuck back in.Not to worry, there's always next season..

Have done a sheitload of little things to ensure the unit is ready to rock and I am REALLY looking forward to the coming events to see how the mods pan out.

Re: MD's Racer-The Flying Brick

Posted: Sun Oct 26, 2008 10:36 am
by PietereQ
Good to hear the car is getting better and better, but regarding your cv joint failure, were these old joints or brand new? If they were old maybe they just did let go? Mine have already circa 1~2 degrees slack, so i guess they need to go but I have hard time finding new ones for gtv6. Ironically alfetta joints are readily available here :?

Re: MD's Racer-The Flying Brick

Posted: Sun Oct 26, 2008 1:43 pm
by MD
The CVs were not new just reconditioned and of course of the 2 litre kind using the 8mm bolt fixings.

Re: MD's Racer-The Flying Brick

Posted: Mon Oct 27, 2008 4:22 am
by Mats
kevin wrote:MD , the white Giulietta with rear wing on had a problem when Rory cut the dedion. He found he could not turn the wheels as the CV's had jammed.
How was the de-Dion modified?

Re: MD's Racer-The Flying Brick

Posted: Mon Oct 27, 2008 9:06 am
by kevin
Will find out but as far as I can remember it was with grinder and rewelding on jig at ends. Maybe grinder blade to thick but let me check before jumping to conclusion.

Re: MD's Racer-The Flying Brick

Posted: Mon Oct 27, 2008 9:54 am
by Mats
I was thinking more in the lines of which way the geometry was changed.

Re: MD's Racer-The Flying Brick

Posted: Mon Oct 27, 2008 2:05 pm
by MD
Basically you are going back to Alfa design but with propper couplings.
Kevin, yeah that's basically it. The key differences are that I am using a CV joint in the centre and a much better and contemporary rubber coupling at each end. This is a result of some expensive trial and error to do a "Myth Buster" that you cannot use Uni's or CV's in transaxle prop. shafts which as you know is rubbish. It is only appropriate in race cars at the expense of some serious noises at idle. Otherwise, "solid" components are tougher and are easier to balance better.

In my case, I just prefer a more quiet transmission and to be a bit more kind to the transmission and so we fitted the rubber couplings which do a great job of dampening out any harsh noises.

As for using the original Alfa donuts, well er.., this is a polite Forum... :D

Re: MD's Racer-The Flying Brick

Posted: Tue Oct 28, 2008 12:04 pm
by kevin
MD, the quality of couplings is shocking at the moment. I seen some serious tensile failures(not debonding) on 4cyl race cars lately. Im not sure if they are been made to origional specs. There is no need to panic for road cars or casual track day cars out there as they dont even take a quarter of abuse as a full race car does.(for non race chaps reading this thread). My next plan is is to machine a coupling out of aluminium and inject a high quality urethane or other into the bolt holes identical to the one on the Scuderia del Biscone site. No reinvention of the wheel here. At least in case of emergncy I can bolt on to origional props and flywheel if there is a failure at an away race.

Re: MD's Racer-The Flying Brick

Posted: Thu Jan 01, 2009 12:09 am
by MD
Well much to my disgust I have had to abandon the brand loyalty and ditch my Alfa tacho. I think the hot Aussie sun on the black binnacle eventually fried the 30 year old electronics. Sorry Paul, we tried mate.

Reworked the binnacle to fit the shift light in place of the tacho and install an aftermarket Yank tacho to do the job.

After the end of year holidays are over, the Brick is going back to the workshop for a pre race check up and so let the 2009 race season begin. Looking to further consolidate our efforts this year.

Re: MD's Racer-The Flying Brick

Posted: Thu Jan 01, 2009 3:21 am
by kevin
Thats one serious shift light. Need your shades on when that thing blings. 8) .
So basically for 2009 your engine is good. Just got to keep box together. have you calculated where your roll centre is on front. Is your rear still stock(Wats linkage).

Re: MD's Racer-The Flying Brick

Posted: Thu Jan 01, 2009 8:18 am
by Mats
MD. I did the same a while back. Interesting to see that the tacho and the datalogger now agree on the rpm... :shock:

Re: MD's Racer-The Flying Brick

Posted: Thu Jan 01, 2009 1:33 pm
by MD
Kevin,
The view of the shift light and the tacho are more or less in your peripheral view as you are looking straight ahead and yes it's a good thing it is only on for a short time cause you could get a sun tan by it.. :D Lucky I don't do any night runs otherwise it would need a day/night screen.
Mats,
This Autoguage tacho is just a budget unit but you can go crazy with these things. Electronically the difference between an expensive one and a cheaper version is whether it works or not.. :)
It does have a feature to manually set the shift light rpm output. Fortunately, like your data logger, my Motec has its own rpm output to a second miniture shift light which is a back up if the filament in the bulb blows. This output is 100% accurate as it represents the engine firing trigger numbers so I can calibrate one against the other, pretty much what you have done.