What is the compliance process?

[bulldog]

I'd like some information from anyone who has gone through compliance for their car after a repower.

What I'm trying to avoid is putting in diff a when I should have used diff X because it's the same manufacturer type of thing.

Any infor much appreciated.

[zep]

I'm pretty sure they wont ask you to put in a new diff. It's not like they know how much power it's making or what power the diff will take.

I think you shuld be ok, many people put larger power engines in their cars and don't upgrade the diff. Those who do are mainly people who are concerned about having LSDs.

[jaygti]

I guess the question is more along the lines of what diff will be an upgrade but not need certing.

So while a Hilux diff would because it's going to require some kind of a-frame bracket to counter the removal of the torque tube, a larger Gemini diff should theoretically not need to be involved in the cert process because it will bolt up to the factory mounts and retain the torque tube (providing it's going into a chevette saloon).

This is a theory I'll be testing at some point, although I have had to get the mounts swapped from the Chevette diff to fit under my hatch. That is the main reason I've painted the Gem diff, so as to cover the pretty obvious non-factory welds. I doubt it will be a problem for the cert, it's been done properly (as the $500 hole in my wallet proves) and I have the receipt to show it, but it will be a while before I put another engine in and don't want a WOF guy saying 'hang on, that diff's been changed, that's a fail!' in the meantime.

[cul8r]

@ Bulldog you want to find a Gemini Wagon Diff, that will bolt virtually straight up, need to change the rear brake line connection, and redrill either the torque tube mount, or the mounts to the floor as the holes are further apart.

I havent done the Piazza so I cant tell you whats needed there..

Cheers,Chris

[mikuni]

I wouldn't upgrade bro, seriously. Yes the chevette diff is rediculously small and ofcourse it will blow yup straight away. Well thats what everyone says anyway. Mine has now lasted 3 trackdays and its not yet showing any signs of giving up (getting noisy or anything). Obviously an decent upgrade to a nice piazza lsd would be great but I DEFFINATELY WOULD NOT go to a gemini diff. They may handle more power but that is yet to be proven. Just because the gemini diff is bigger does it really handle more power? Has anyone ever blown a chevette diff? The answer is no. Its a tight diff that always spins both wheels where as the gemini will only grab one, no matter what you do. Converting to gemini is a waste of time unless you use piazza disks and recond lsd at the same time.

I talked to my certifier about firstly my g200w conversion, secondly turboing this engine and finally my new conversion. At no stage did he express concern at the diff I was to be using. He wanted me to upgrade my front brakes to vented disks and rebuild the rears to ensure they would cope with the additional loading. That is it. I have not yet heard of a certifier being concerned with the ability of the diff to cope with the power output.

[zep]

...and that is mainly because the certification process is about the safety of your mods. Blowing a diff isn't really an unsafe thing to do, so you should be all good.

Might have to get a drive shaft loop tho.

[jaygti]

I'd agree with Mikuni, even though I'm part-way through putting a Gem diff in mine.

The Gem diff is significantly larger and therefore significantly heavier, which is going to add un-sprung weight. That will affect the handling and ride quality, although how much I've yet to find out.

In terms of strength, maybe they are stronger, but if Mikuni's not having problems, it's probably fair to say it's not actually needed.

As for the Piazza disks and LSD, nice idea but everyone knows they are getting rare and everything I've seen on Tardme has been a complete ripoff.

Only reason I've stuck with the conversion is the difference in the gearing, the Gem diff is taller and should hopefully compensate for the piddly 175/50/13 tyres I'll (eventually) be putting on the car.

[mcqunt]

highly likely that it is more a question of torque more than horsepower when trying or not trying to blow a chevette diff, mine gave out in my first wagon with larger wheels than brads
and my g200w not really due to abuse but 4 grand in 3rd gear, thats why i went to the gemi
diff