6 Speed gear ratios

[Stoffa]

What final drive ratio can you get a DCCD 6 Speed?

What RPM's do 6 speeds do at 100km/h in 6th with 215 40 R17's?

[funkytown]

final drives are all 3.9 are they not?

about 3100 at 108km for me.

the gb ratios are all in a sticky in the gb category stoffa

[Stoffa]

Im about to start using my car as a daily driver im trying to find ways to save gas.

My Type R box is 4.44 and sits at 3300rpm at 100km/h

Just bought one of these to use for closed loop lean cruise

[albaru]

 Stoffa said:

Im about to start using my car as a daily driver im trying to find ways to save gas.

Hmmm, not entirely sure that's possible ;D

I've got a wide band and had closed loop switched on for a while and tried really really hard to keep within the closed loop lean cruise but found I couldn't hold it for long at all. I could see that the leanness had increased while cruising but that for me didn't translate to better mpg. Hopefully ymmv ;D

I suspect that the car just likes petrol

[X]

to save gas, park it up for another 2 year bro hehehe

for some strange reason my car lovessss petrol too!

[Stoffa]

did dan set yours up al? he seems to think it'll pay for itself within 12 months of daily driving.

I'll get him to set mine up and throw some boost at it with a litle more tuning as well, so probably end up using more gas anyway haha.

[Stoffa]

 X said:

to save gas, park it up for another 2 year bro hehehe

for some strange reason my car lovessss petrol too!

3 years smart ass haha

[albaru]

 Stoffa said:

did dan set yours up al? he seems to think it'll pay for itself within 12 months of daily driving.

I'll get him to set mine up and throw some boost at it with a litle more tuning as well, so probably end up using more gas anyway haha.

Yeah Dan set mine up too. It only worked on the flat road with absolutely no throttle change. Once there's a throttle change the a/f ratio dives back to normal then the closed loop brings it back up to ~14.xish. I persevered for quite a few months but don't think it improved my petrol consumption. For reference my city/highway mixed cycle is 7 km/l which always includes highway driving due to where I live and has not changed. My 'road trip' usage is still 10-11 km/l.

[johnny5]

my car does 2900rpm at 100kph if thats any help

[Stoffa]

if your running stock sized tyres (225 45 17) you'll have a much bigger rolling diameter hence dropping under 3000 rpm

[johnny5]

 Stoffa said:

if your running stock sized tyres (225 45 17) you'll have a much bigger rolling diameter hence dropping under 3000 rpm

right on didn't read the tyre size you stated properly sorry mate

[gotasuby]

doesnt matter what tyres you running on speedo will still read the same proportionally to rpm in each gear

[funkytown]

i run 225/45/17

it doesnt run any lower at cruise than a 5mt stoffa. just a touch over 3grand. come over all il prove it

[Stoffa]

 gotasuby said:

doesnt matter what tyres you running on speedo will still read the same proportionally to rpm in each gear

but over all youll end up using more gas running a smaller rolling radius

[Pappu1]

i was thinking of doing a similar experiment on gdb ecu

set the cruise afr to 15.2 from 14.7

will 15.2 cruise closed loop be too lean or is that ok?

apperently some toyotas run in the 17 (a toyota guy was telling me so i have no way of checking that info)

anyway,

15.2 - is that too lean for closed loop running?

also planning to change switchover loops so stays closed loop longer...

dunno how much better the mpg will get..

[B4 2000]

Get a legacy gearbox mine sits bout 2700RPM at 100km/h iirc

Ive never topped 4th gear yet, even at speed of 194km/h on the straight on Ruapuna ;D

[gotasuby]

I usually tune for 15.5:1 cruise light load and have gotten 9.5l per 100 with my driving with id1000 which is pretty good.

[Pappu1]

15.5 ...

that wud be something u deem safe on light loads and closed loop driving?

sounds like a good mpg gainer tho

[gotasuby]

I have no problem doing it at all and never had any issues with anyone's cars at that. Only from 10in mercury down though.

[Pappu1]

nice..

i will start off at perhaps 15.2 as planned and work my way to 15.5 hehe

just to see the differences and also any potential issues

[scottspeed]

Tune as lean as the car will happily run on light and off throttle, its only as it starts to boost it will kill the engine if too lean. Depending on heads and cams, some subi engine setups will run as lean as 20:1

If you have an adjustable computer normally lean off in cruise until the engine stutters or starts to loose power and requires more throttle aplication, then add a little bit of fuel back into tune. If the car has badly efficient heads or cams then the mixture will need to be fairly rich, and you sometime find "by leaning out" you actually use more gas as the car requires more aggresive driving or more throttle to cruise along at a given speed.

A larger turbo always helps if your after economy as it allows the spool up to be higher than the cruising rpm where std ones will quite often surge in and out as they try to make boost.

[Pappu1]

hmm if leaning was done but not to extreme - in the 15.2 region, that wouldnt cause more gas usage due to need to drive more aggressively wud it?

[Stoffa]

 B4 2000 said:

Get a legacy gearbox mine sits bout 2700RPM at 100km/h iirc

Ive never topped 4th gear yet, even at speed of 194km/h on the straight on Ruapuna ;D

now we're talking, is that a 6 speed?,

what size tyres are you running?

also whats your gearbox code?

[rex-leggy]

i believe his leggy has a 5 speed ?

[B4 2000]

 Stoffa']

now we're talking, is that a 6 speed?,

what size tyres are you running?

also whats your gearbox code?

[quote name='rex-leggy said:

i believe his leggy has a 5 speed ?

Yes I've got the standard 5-speed.

Tyres: 215/40 R18

G/B code: TY754VBBBA This is with the open front diff, TY754VBBCA < Helical LSD front diff. Those came on RevCs, MY01 and i think RevDs as well!

More numbers: at 50km/h (city cruise) 4th gear sits @ ~ 1800RPM, 3rd gear @ ~ 2350RPM