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Mats
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Re: A cheap way to fix a weak point of transaxles's gear box

Post by Mats »

No that's not accurate, it's all about torque and heat management... Keep the torque at reasonable levels and increase the rpm and you can easily have 350Hp without problems if you can keep the oil (and gears) at correct temperature.
A gearbox cooler and pump is a must, add a spray pipe inside the gearbox for oil distributions directly on the gears for cooling/lubrication and you will have a much more reliable system.
Ignore the temperature and drive without sympath for the mechanical parts and you will have problems with any gearbox. :wink:
Mats Strandberg
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GTV 2000 -77 - Died in the fire.
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Re: A cheap way to fix a weak point of transaxles's gear box

Post by 75evo »

I like the sequential setup on the 600 bhp Norwegian GTV6 Turbo. Selholm 6-speed with Volvo 940 GL differential. But sequential gearboxes are extremely expensive (just the box alone), before taking into account custom work needed to make it work. It can buy you a few 24V engines (maybe 10 - 20). So sometimes rebuilding an Alfa box for Euro 1500 with all the special modifications become cheap in comparison.

But still, if I could get a hand on one of those 6-speed sequential hmmmmmm....... just looking at Alfaholic's 6-speed sequential (not sure which mfg) with pneumatic shift (Geartronics gear ECU) on on of their 105 cars makes me drool.

One of the problems with these gearboxes, I feel, is that center piece that fits between the gearbox and diff. casting. The cast aluminum piece which holds the bearings seem to be very weak and I've had 2 failed! Parts of it where the shaft bearing goes simply crumbled.
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Re: A cheap way to fix a weak point of transaxles's gear box

Post by gatouille »

You're right Mats I made shortcut between powxer and torque because my english is poor.

Here is a part which is trying to prevent breaking clutch housing on V6 24S (270 HP and 32 NM torque :wink: )

Image

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This genuine V6 24V 3L (all parts are stock) have specials manifolds exhaust and intake, injection sybele and motors give between 260 and 270 hp 32 nm torque
With these thez break every boxes...
That what I meant Mats sorry for my english :oops:
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Mats
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Re: A cheap way to fix a weak point of transaxles's gear box

Post by Mats »

No problems!

But you mean 320Nm right? Or maybe 32Kgm?
Mats Strandberg
-Scuderia Rosso- Now burned to the ground...
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GTV 2000 -77 - Died in the fire.
155 V6 Sport -96 - Sold!
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Re: A cheap way to fix a weak point of transaxles's gear box

Post by gatouille »

Yes 32 kgs, thanks :lol:
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Re: A cheap way to fix a weak point of transaxles's gear box

Post by kevin »

Gatouille , I broke nearly three gearboxes in one season when using the 3.0 24 v . ( all the breakages were in the crown and pinion ) .I was about to move the gearbox upfront when I decided one last time to make some changes which so far have proved ok ( touch wood) . But I have also changed to a 3.7 24v motor which has 192 kw on the WHEELS . So things that I changed in the gearbox side was the oil to Redline 75w90NS , then to remove the heat I run a motul oil cooler/pump and I move the brakes to outboard . This has taken a lot of heat off the gearbox ( also a lot of money out the bank :D ) . I also changed from a 10/43 to 10/41 due to the torque characteristics of the 3.7 . I barely use second gear . So the 3.7 has led to smoother driving because you only rev to a max of 6500rpm instead of 7800rpm .
As I said I have no broken boxes so far and I think / sure it's mainly due to removing the heat from the box .
Now if I break this box THEN I have a BMW 5speed E36 box , a BMW tunnel , adaptor plate and clutch/flywheel ready to go in . Actually we just making three of these kits at the moment which one of them is going into joemarts GTV .
I got two more races left this season and I will wait and see .
Good news is there are guys here running highly modified 2.0 twinspark alfetta gtv revving to nearly 9000rpm also lightening gears like you and they are very reliable .( ironically they have no coolers and have inboard brakes but very light clutch set ups .)
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Re: A cheap way to fix a weak point of transaxles's gear box

Post by gatouille »

Thank you Kevin for your very interesting answer, 3,7 24S, :shock: if you have too much power please send me :lol: :wink:
Introduce mysel :
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