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[Immortality]

What speed do you exit the hairpin?

 

[Veewhyfan]

Somewhere between 60-80km/h. . I think. And checking the calculator;

Gearing Analyzer with Shift Tracer

Enter gear ratios, tire and diff ratio to analyze RPM vs speed at shift points with tracer

apx6u.app.goo.gl

That should bring up a calculator with shift points at 6200, Getrag 5sp and the standard 3.08 diff, with 17" wheels.

With the stock diff, (assume 3.08) 60km/h, in second gear, puts the ecotec at ~3350rpm. Not bad really, below for more math;

(60km/h)
3.08 = 3350rpm
3.5 = 3830rpm
3.7 = 4020rpm
3.9 = 4260rpm
4.1 = 4500rpm

Then taking those diffs out to a theoretical shift point of ~6200 in 2nd gear gives you.

3.08 = 111km/h
3.5 = 98km/h
3.7 = 93km/h
3.9 = 88km/h
4.1 = 83km/h

3.5 ratio looks good really.


Hang on... im sure this is making sense.... .. wait a seccond...

I need to take my car for a drive to check some of these speeds vs RPM.. im doing something wrong here.

 

[Veewhyfan]

Well well well Diff update!

Turns out I ended up with a 4 bolt VT diff when the Manual box was swapped in... Hmmmm not mad I suppose. but who knows what condition it's in. I'll know my fate tomorrow when opened at the shop.

Diff man suggest 3.7's are the way to go. loading up the Calculator below, yeah puts 5500rpm in 5th at ~220km/h. I feel like at the end of the main straight in Sydney and Philip Island I was near ~190km/h, so this feels like a good use of the engine.

Gearing Analyzer with Shift Tracer

Enter gear ratios, tire and diff ratio to analyze RPM vs speed at shift points with tracer

apx6u.app.goo.gl

Had to remind myself of the engine output on these stocky things, Sit down everyone..

Peak Newtonians at 3k ripems.
Peak KilloMangs at 5k ripems.

Now add in those 1.9 rockers, extractors, lets be conservative and assume I've just moved everything 500rpm up the rev range.

Now a 5500rpm shift point makes sense. The gear changes will now look like this:

2nd, ~3500rpm,
3rd, ~3900rpm,
4th, ~4400rpm
5th. Well now I'm doing ~220km/h and thats enough (if it even manages to get there...)

This all keeps me well within the expect 3.5-5.5k power band, should be good fun!


Also, this bloody turned up in my search results;

Walkinshaw 18" wheels and nankang Ar1 tyres - Australia's #1 Performance & Motorsport Marketplace - my105.com

I'm selling a set of almost brand new 18 inch walkinshaw style wheels and nankang Ar1 225 40 18 tyres that have done one track day. The tyres have unbelievable grip but the low profile side wall doesn

www.my105.com

I know they be rip off walkies but heck.. thers some good value there. Nankangs looks ok, wheels look ok oh bother... really don't want to dump another 1500 at this thing but look at em. Would you just look at em. Those tyres are ~300 each.. ah farken 'el.

Actually what do 18" walkies look like on a VY. Probably dumb actually. Yeah that makes me feel better about this..

 

[Veewhyfan]

Actually what are the rip of walkies like....

 

[Veewhyfan]

Oh it feels better then I thought it would.

The diff man had the car an extra week so he could confirm the gear set were set correctly. Ah yes. I've ended up with a rebuilt diff, bearings, seals, new LSD center, new pinion the works. I was nearly able to reuse the pinion but it was worn enough that it make sense to bin it. The entire experience was now 2x as expensive as planned

He tells me to keep it under ~80km/h for a week now as it settles, and it's going to be tricky because it feels so lively. A quick test on my favourite piece of inner city racing segments, (the Hoddle street, M3 Eastwood entry ramp) has the car appearing to sit with much less under-steer, I have the impression of it pushing from the rear, even with the rear bar set to it's softest and the front on the highest.

Party Time

 

[Immortality]

Yes it will drive through a corner different under power, now with an LSD it'll want to drive straight as the rear wheels want to turn at the same speed. You can use the throttle to steer with the back of the car.

 

[Veewhyfan]

How good is Envyous customs and their body diagnostics software.

Was destined to correct the speedo after the 3.7 diff, landed with a ppk setting of 7034 with my 17” wheels. Bloody bang on with the gps. No excuses for speeding fines now..

Also in driving around checking the speedo, passed a clean clean white vy with ~20” steelies. Looked great with its chrome center caps and black nuts. haha.

 

[Immortality]

I left the factory 3-4km/h speedo error at 100km/h when I did mine, the missus has a heavy foot so I need to save her from herself. But yeah, Tazzi got a good thing.

 

[Veewhyfan]

Thats probably a good idea Immortality.. Having the psychological error in favour of being under the actual speed.. Yeah good one.

 

[Veewhyfan]

OH No..

18x8, 225mm Nankang Ar1's.. Picking them up next weekend,

I really really want to be faster then my mate in his Mx5