Gearbox ratios

[Piggy]

Ok...

Only recently dawned on me with doing more miles in both motors (2.1 306 n 2.0 206)...

They both have "hdi" boxes...but rev at different rates for same speed/gear.

Basically the 306 2.1 with the "hdi" box will do 30mph in 4th gear at 1000rpm and 70mph in 5th at 2180/2200rpm ish.

The 206 is about 300/400rpm higher for both speeds.



Thoughts?
My first one was either my speedo or rpm were out...but they generally work or dont!

[Frosty]

Some 206s have an 'Eco' gearbox. Mark has 1 that he got his hands on. Pretty hard to get hold of I believe

[DemonDriverDan]

Eco box would have longer gearing so the RPM would be lower for the same speed?

Same size wheels and tyres on both cars?

[adam b]

There are literally loads of different gearboxes

[Poodle]

Wheels and tyres won't make a difference to the reading on the speedo. Could i have the reg of the 206 please? Or if you don't want to hand out the reg is there any chance you could get the relevant part number off of servicebox?

[bashbarnard]

Sounds like the 2.1 has the eco box in.both me and lu run/ran hdi 306 boxs and all three ive got have all ran at 2500 at 70.

[Magenta Sunset]

final drive ratio? (imho)

[adam b]

There are 3 different boxes on gti6s so how you think there's only two on both hdis...

[Piggy]

Wheels and tyres won't make a difference to the reading on the speedo. Could i have the reg of the 206 please? Or if you don't want to hand out the reg is there any chance you could get the relevant part number off of servicebox?

Just to confirm...

The 206 has what I would consider the NORMAL ratio for a hdi box.

---

Sounds like the 2.1 has the eco box in.both me and lu run/ran hdi 306 boxs and all three ive got have all ran at 2500 at 70.

But the eco box was a from a 206. 

The 206 eco hdi box is hydro n nothing like the hdi box I have in the 306

[Toms306]

Sure your 2.1 rev counter works? 30 in 4th at 1k does sound low, 6 speeds are usually higher than that even!

There are loads of ratios as already said though, its not as simple as one box covers all with the same engine.

[bashbarnard]

Yeah the 3 206 is what i would consider normal as well for hdi box. Rev counters cant really be wrong on these. They work or they dont generally so not really sure you may have some unknown box in it. Parts bin special box so to speak.

[Paul_13]

Wheels and tyres won't make a difference to the reading on the speedo. Could i have the reg of the 206 please? Or if you don't want to hand out the reg is there any chance you could get the relevant part number off of servicebox?

If you're changing the overall diameter of the wheels/tyres it will have an effect on the speedo unless you match the vss cog to suit.

Which is why you get different colour vss cogs (generally 306 gti6 - black, 205 gti 1.9 red cog with white diff cog, 205 1.6 gti different again etc etc)

Putting 13" wheels for example on a 6 will cause the speedo to massively over read (I know that's not possible without changing the brakes bit that's just for an example)

---

Putting 14" wheels on my 205 dt caused to speedo to over read exponentially, at 70 mph it was at least 10mph different to having the 15" wheels on.

I changed the vss sensor to that of one suited for 14" wheels and the speedo reading was more or less accurate.

Speeds were tested with the same sat nav

[Poodle]

Sorry i should have been more specific: it won't make a difference to the speedo vs rev counter, as per the op. Obviously actual speed will be affected, but not the read out.

Ah i've misread that then, in which case; reg of the car you got the box from?

Adam, don't suppose you've got any more useful info to share? Nice to know there are more options out there at least.

[zx_volcane]

Speedo will deffo over / under read if got wrong cog in speedo drive!

Double check with gps Vs rpm

[Piggy]

Hmmm.
Nah I dont have knowledge of car the box came from, just 306hdi. Was 3yrs ago!

Will try gps laters

[Poodle]

Shame, would have been too easy i guess.

[Dum-Dum]

The gear ratios in all the BE3/4 boxes (bar the GTi6) are the same which is why they all have that huge gap between certain gears. It's only the final drive that differs and this includes the 206HDi eco box

Peugeot have alot of final drives to use in these boxes


I get the feeling that your clocks are slightly out as IIRC 70mph in a HDi box is 2450rpm (on the scanguage) so 30mph should be 1050rpm. Obviously thats within about 35rpm as each mph covers about 35rpm


At 2200 at 70 you are close to the 206hdi eco revs but you'd notice the boxes are physically different and the gearbox mount needs altered.

[Piggy]

Ok...
Long trip...
Satnav says my speedo is out by 3/4%.
Basically 70mph is 72mph on my speedo. At 2250rpm.

[darrenjlobb]

RPM gauge deffo correct?

[Dum-Dum]

You say 3-4% out but at what speed, is it 3-4% at 70 or 100mph (where most people check) but what about at 20mph or 50mph?

For testing you could go out and hold the car at every 500rpm then note the speedo speed and gps speed (on a flat road of course) and then that'll show if and where any major discrepancies are.

[Piggy]

RPM gauge deffo correct?

This is my only thought... Duno how to check though tbh.
I assumed they worked or didnt

---

You say 3-4% out but at what speed, is it 3-4% at 70 or 100mph (where most people check) but what about at 20mph or 50mph?

For testing you could go out and hold the car at every 500rpm then note the speedo speed and gps speed (on a flat road of course) and then that'll show if and where any major discrepancies are.

Nah its same across the whole range. Only 1mph or so at 30/35

[darrenjlobb]

Laser gun on timing pulley, This is how i calibrate old cars with no tacho on dyno

[allye]

Rev gauges are not accurate and shouldn't be taken for gospel! I wouldn't mind betting they are the exactly the same but gauges are reading slightly differently and/or different size tyre and wheels.

[Piggy]

Rev gauge was out...must have been knocked

[welshpug]

gear ratios are definitely not the same in be boxes, thats the ma sport gearset youre thinking of.

[Dum-Dum]

gear ratios are definitely not the same in be boxes, thats the ma sport gearset youre thinking of.

Except the GTi6 all the ones I've worked out from service box are the same (with the exception of the FD).

[welshpug]

keep going, theres massive variances.

[zx_volcane]

keep going, theres massive variances.

Variances on the diesel be boxes? be good to know if you've info

I've only come across the 1.9td and hdi 'style' boxes with circa 500rpm difference, and same gaps between gears, including the horrific wasteland between 2-3rd

Plus the 206 'eco' box

Heard rumours of some citroens having different ratios or fd, but nothing concrete

[Dum-Dum]

keep going, theres massive variances.

Variances on the diesel be boxes? be good to know if you've info

I've only come across the 1.9td and hdi 'style' boxes with circa 500rpm difference, and same gaps between gears, including the horrific wasteland between 2-3rd

Plus the 206 'eco' box

Heard rumours of some citroens having different ratios or fd, but nothing concrete

The 206 DW10 eco box has the same ratios as the 1.9D 1.9TD HDi etc just a different final drive yet again.
Even the XSI and other petrol BE3 boxes are the same IIRC

So welsh pug, which cars have different gear ratios?

[Poodle]

Yeah would be really interesting to know, or least give us a clue as to where we might find the information.