24 replies to this topic

[Evo-00x]

Hi guys I just thought I'd get only a few of you to jot down what RPM you are doing at 100 and 110kmh in 5th gear in your AWD cars.
If you have something other than the speedometer to check your speed use that instead, as the speedo can be out with your wheel/tyre combo.
Would be good to see a mix of GVR4 and EVO I/II and III in here with 14-19" wheels etc.

I'll start off:

CC AWD coupe (1240kg)
Speed: 100kmh / 110kmh (Apexi AVCR reading from the ECU)
RPM: 3000rpm / 3200rpm
Gear/Ratio: GSR 5th gear, 3.545 rear diff ratio
Tyre dimension: 215/40/17 tyres (17x7 wheels 40 offset)

[90xsi]

evo II
speed: 100kms (avcr)
Rpm: 3400 - 3500
Gear ratio: 5th gear evo 2 drivetrain
Tyre dimension: 215x45x17

[Paul]

Wouldn't it be better to use a completely external speedo like a GPS etc etc?

An AVCR just reads off the standard speed sensor in the back of the cluster much like the stock speedo.

[Evo-00x]

The AVCR gives a truer speed and rpm reading from the signals going to the ECU. The stock cluster needles and readings can be a bit off.
The rpm and speed reading on my AVCR (going to the ECU) differs slightly to what you see on the cluster

[banned]

Arghh. Don't have a working Evo at the moment.

But I submit:

'04 Sti

Speed: 100kmh / 110kmh (Speedo)

RPM: 2700rpm / 3100rpm

Gear: 6th Gear

Tyre Dimension: 225/45 r17

Let me play along..

[GSRWRC]

Will let ya know next time I drive the car, I suspect mine might be similar to yours though.

[DOUGMO]

evo II
speed: 100kms (avcr)
Rpm: 3400 - 3500
Gear ratio: 5th gear evo 2 drivetrain
Tyre dimension: 215x45x17

mines pretty much the same (as I guess you would expect being an evo 2 aswell)

[Evo-00x]

Anyone have the stock 15" OZ racing rims on (probably 60 series tyre?)

[SIKWPN]

EVO 3

Speed: 100kmh = 3000rpm - 3100rpm ish ( Speedo )
Speed: 110kmh = 3500rpm ( Speedo )
Gear ratio: 5th Gear/Evo 3 driveline
Tyre Dimension: 215/40/17

Edited by SIKWPN, 15 August 2010 - 02:52 AM.

[HYP04]

I never tested my EVO3, but will see how it goes in a few weeks.

Correct me if im wrong, but "tyre diameter" will not affect the ratio between the KM/h the speedo or rpm for the tacho for which you are currently reading, only the "actual" (land) speed will change. As measurement is calculated from ratios from the output rpm of the mechanical drive (number of pulses to the ECU).

So speedo/tacho will still read the the same ratio with any tyre combo, only change in diff/gearbox ratios will change what the speedo to tacho ratio you are reading.

Another way to check this would be land/actual speed and rpm on a dyno for a true figure. If i remember i check mine on the dyno next week.

[Evo-00x]

The tacho and speedo run independent to eachother so they will never be consistent with a change of tyre diameter. ie. engine has to work harder or easier to maintain speed by spinning a larger or smaller diameter wheel one entire revolution. This effects rpm 100%.

[BMGTZ]

The tacho and speedo run independent to eachother so they will never be consistent with a change of tyre diameter. ie. engine has to work harder or easier to maintain speed by spinning a larger or smaller diameter wheel one entire revolution. This effects rpm 100%.

well since the engine is driving the gearbox.....which has the speedo drive in it. pretty much there will be NO difference in indicated speed and rpm no matter what tyre wheel combination is used.

you could put roller skate wheels onto it and it will still indicate exactly the same way. You must use an external speed measuring device.

[Smutt]

GSR 1.8 ltr with evo 3 driveline

These results taken off the speed/ tacho in fifth gear:

100 km/hr = 3200 rpm
110 km/hr = 3500 rpm

215/40/17

Edited by Smutt, 15 August 2010 - 01:10 PM.

[Evo-00x]

thanks for picking that up Brian. I was following on from Hypo4's comment about the dyno but wrote tacho instead of dyno . With larger/smaller diameter tyres it'll effect his rpm 100%.

[JETGSR]

CC AWD GSR Lancer
Speed: 100kmh / 110kmh (Haltech E8 ECU)
RPM: 2750rpm / 3050rpm
Gear/Ratio: E3 5th gear, 3.545 rear diff ratio Fitted to E3 mech LSD - GSR front C & P fitted to E2 LSD <- see it can be done!
Tyre dimension: 205/40/17 tyres (17x7 wheels 45 offset) + 4mm spacers

and a mighty handsome driver!

[Evo-00x]

Awesome, thanks Troy. You've just answered one of my main reasons for starting the thread as I also wanted to know how much rpm would be at 100kmh when using the 0.617 Evo 5th gear (Evo I-III box) with GSR front and rear diff ratios
That'll help you with cruising on highways in 5th and save a little on fuel and noise too.
I will have to see what my Haltech E8 reads compared to the AVCR, although Id expect them to read the same.

[SIKWPN]

is it possible to do a only 5th gear from a gsr into an evo box to make it rev lower ??
its just an idea so dont bite me

[GSRWRC]

is it possible to do a only 5th gear from a gsr into an evo box to make it rev lower ??
its just an idea so dont bite me

Absolutely, using the .666 GSR 5th is a common mod for an Evo 'box.

[Evo-00x]

EVO 4th (0.862) to EVO 5th (0.617)
EVO 4th (0.862) to GSR 5th (0.666)
The change in 5th gear would make a noteworthy change in the gap between your shift from 4th to 5th gear.
The significant change in rpm in 5th gear, however, would come from a different front and rear diff ratio (ie GSR front and rear crownwheels and pinions put inside your EVO box and rear diff housing).

Edited by EVO-00X, 19 August 2010 - 04:09 AM.

[JETGSR]

If you are going to use a Viscus front LSD you will need to watercut the crown wheel to fit the LSD

where if you use a full mech I believe the crown fits with no cutting <- but I'm not 100% on that