U2Q7 ATR gearbox into 4th gen - what to do regarding VSS?

Jack · Post by **Jack** » Tue Jul 05, 2016 2:13 am

As some of you may be aware, I'm in the process of a full ATR conversion on my BB1.

I've been told I need to change either the gears inside the VSS, or the VSS ring gear (?) in the gearbox that drives the VSS. I really don't know a lot about this side of things so any help/pictures would be great. I've got both VSSs out although I managed to break part of the mounting bracket on the ATR one (I don't think I need this as I think I have to use the Prelude VSS, and either way I have another donor ATR waiting to be stripped anyway.)

I've tried the Prelude VSS in the ATR gearbox and it won't go all the way in (been very careful not to force it as I don't want to risk damaging anything. I assume this is to do with the bottom half of the Prelude one being a lot longer.) Do I just swap the ATR bottom half of the VSS assembly onto the Prelude top half, or is it more complicated than that? I'd like to try and avoid opening the gearbox up if possible...

Any help much appreciated! Thanks

hondaddict · Post by **hondaddict** » Tue Jul 05, 2016 5:08 am

In way of keeping your speedometer right, the only solution you have is to replace the ATR VSS gear ( the one on the LSD) with the Prelude VSS gear.
Then you will use your Prelude VSS and all will be fine.

Correct me if i'm wrong but i think this is the way to go, unfortunatly you have to open the gearbox to do the swap ...

Dennis van dijk · Post by **Dennis van dijk** » Tue Jul 05, 2016 6:31 am

Is this the same with a 5th gen lude?

Post by **Vtecmec** » Tue Jul 05, 2016 9:24 am

I'm sure you can split the two VSS's and use the top of the lude one and the bottom of the ATR.

bennyboy · Post by **bennyboy** » Tue Jul 05, 2016 9:54 am

I was in a slightly different scenario - mine is my original M2F5 Prelude gearbox, with ATR diff added. (and H22A8)
I had to swap VSS gears as the readings were out. I was able to remove the gear and the spline and swap it over, is there a circlip or something? It was in 2012 and my memory fails me on the details, sorry.

hondaddict · Post by **hondaddict** » Tue Jul 05, 2016 12:04 pm

Vtecmec wrote:I'm sure you can split the two VSS's and use the top of the lude one and the bottom of the ATR.

The bottom part of each VSS must go with it's own gear, ATR and Prelude VSS gear are different

Post by **Vtecmec** » Tue Jul 05, 2016 12:24 pm

How do you know, split them and have a look.

hondaddict · Post by **hondaddict** » Tue Jul 05, 2016 5:32 pm

Vtecmec wrote:How do you know, split them and have a look.

Sorry, maybe i'm not clear, i'm not at ease with English.

What i mean is that the gears of the ATR vss are different from the gears of a standard Prelude.
If you keep the ATR vss gears ( the one that is on the differential and the one that is on the down part of the vss sensor) , the speedometer would give a wrong information because the Wheel ratio between the Prelude and the Accord is different.
This is why these vss are specifics to each car.

So if you want to have the right information at the speedometer, you can also change the size of the tires and keep the ATR vss, it is another possibility

But you can not use the ATR vss sensor without it's differential gear, and it is the same with the prelude vss, as shown on the picture above, you can see that the vss sensor gear have a different diameter, a different size and don't have the same number of teeths.

As you say, he can use the bottom part of the vss, but the problem don't sit here for me, the problem will be with the speedometer and not with the vss, as you say, if he keeps the bottom part of the ATR vss with the ATR gearbox, it will work fine... ... but with a wrong speedometer.

Please forgive my bad English, i hope this time that i'm more understandable , if not, don't take any offense in my words , i'll do my best to be clear

Post by **Vtecmec** » Tue Jul 05, 2016 6:46 pm

Perfect English.

How far out would the reading be? Maybe an electrical signal convertor?

Dennis van dijk · Post by **Dennis van dijk** » Wed Jul 06, 2016 12:13 pm

Vtecmec

Same as i tought

Used a speedohealer for my s2k cluster im my bb9