How to: Convert to a 5-Speed Gearbox

[DeanS15]

wtf - i'd pull the car out of there if it was me. theres no way it should take 3 weeks in a professional garage, apart from the drilling and mounting for the master cylinder, the rest is just swapping of parts....

 

[_Wing_]

You need the s14 crossmember, it's definitely different to s15

 

[Dextanator]

"If you are putting a 6-Speed into an S14, the parts are just the opposite of the above, but you will need a signal for the speedo."

I have done this. just wondering what u mean by a signal from the speedo?? cos my speedo is not working and tryna fix it thanks

 

[Keisu]

You need the s14 crossmember, it's definitely different to s15

I compared S14 and S15 crossmembers and they share the same dimensions

 

[Dextanator]

If you are putting a 6-Speed into an S14, the parts are just the opposite of the above, but you will need a signal for the speedo.

:thumbs:

I have done this. just wondering what u mean by a signal from the speedo?? cos my speedo is not working and tryna fix it thanks

 

[_Wing_]

I compared S14 and S15 crossmembers and they share the same dimensions

They will not interchange... try it

 

[_Wing_]

I have done this. just wondering what u mean by a signal from the speedo?? cos my speedo is not working and tryna fix it thanks

It's because there is no speed sensor in the 6 speed gearbox... with no speed sensor you don't get a speedo reading... as you found out. You can try to convert it to a s15 diff where the speed sensor sits in the s15 and then manipulate the signal so that your speedo reads it correctly.

 

[Keisu]

They will not interchange... try it

Yea but someone said that the S14 crossmember fits, but they had same dimensions and bolt holes. My problem is that the S15 crossmember doesn't fit properly, the bolt holes are like 3 cm away from each other.

If you've swapped to the 5speed tranny, which crossmember are you using?

 

[Dextanator]

It's because there is no speed sensor in the 6 speed gearbox... with no speed sensor you don't get a speedo reading... as you found out. You can try to convert it to a s15 diff where the speed sensor sits in the s15 and then manipulate the signal so that your speedo reads it correctly.

My 6 speed s15 gearbox does have a speed sensor. some s15's read the speed off the gearbox not the diff. the car my gearbox came out of had no speed sensor on the diff... it read speed off the gearbox. i just need to know what i have do to change the signal so the s14 dash will read it

 

[meddler]

I bet your 6 speed is not the original gearbox then.

 

[_Wing_]

Yea but someone said that the S14 crossmember fits, but they had same dimensions and bolt holes. My problem is that the S15 crossmember doesn't fit properly, the bolt holes are like 3 cm away from each other.

If you've swapped to the 5speed tranny, which crossmember are you using?

I don't get it... you have two crossmembers and you're saying they're the same. I'm trying to tell you s14 and s15 are NOT the same. If you have two of the same crossmembers and they both don't fit then you have two of the wrong ones. Does that make sense?

 

[_Wing_]

I bet your 6 speed is not the original gearbox then.

QFT + the diff isn't standard either

 

[Keisu]

I don't get it... you have two crossmembers and you're saying they're the same. I'm trying to tell you s14 and s15 are NOT the same. If you have two of the same crossmembers and they both don't fit then you have two of the wrong ones. Does that make sense?

I suppose I shouldn't trust my eyes then, gotta try it on the gbox and decide afterwards ;(

 

[DeanS15]

I can clear this up in the middle of a 5 speed swap and though the cross members look the same and have the same dimensions, they are exact opposites. The s14 box mounts located further forward so the raised part to bolt to the body is on the opposite side to s15. The actual mount is exactly the same. I can put pics up if required

I have also made a list of the bolt sizes for the s14 box so you can go to your local hardware supplier and get them off the shelf. Assuming that you start from the top right hand corner of the bell housing as bolt 1 (the one with the rubber hose and breather attachment) and work clockwise, here are the sizes and lengths.

All m12 bolts are 1.75mm pitch and all m10 bolts are 1.5mm pitch. These are the most commonly available. Measurements are the bolt length only, doesn't include head or spring washer so if you get the bolts and use a spring washer and plain washer with each they should fit perfectly....

1: m12x65mm
2: m12x75mm
3: m10x60mm
4: m10x80mm
5: m12x80mm
6: m10x60mm
7: m12x30mm
8: m10x30mm
9: m10x60mm
10: m10x60mm
11: m12x60mm
12: m12x70mm
13: m12x70mm
14: m12x65mm

As said I used a plain washer and spring washer on every bolt, measurements take this into account. I'm using bolts not set screws as actual bolts are a little stronger due to not being threaded the entire length. Grade 8.8 weren't my first choice but they are used to bolt truck bodies on and tow bars so will be fine. there are also 14 fixings so this won't be an issue, also higher grade bolts generally come with hex heads which would make them even harder to install. Hope this adds to this useful thread

 

[DeanS15]

By the way cheers for the right up andeep helped me a lot.