1.3cl 5spd gearbox onto a 1.0 boulevard...?

Chat about your MKIII (86C) inc GT/G40 Polo
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pete69zx
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1.3cl 5spd gearbox onto a 1.0 boulevard...?

Post by pete69zx »

has anyone transfered a 1.3cl 5spd gearbox onto a 1.0 boulevard?

all this is in the thinking that a 1.0 boulevard has a 4spd gearbox?

i guess the ratios will be pretty different, but.... how badly will it affect driveability or MPG?

thanx
Gareth_GT_Hatch
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Post by Gareth_GT_Hatch »

same first 4 gears + an extra one basically. Should be ok assuming the boulevard is a mk3? Just remember to get the front gearbox mount from the 5-speed as its different on the 4-speed.
pete69zx
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Post by pete69zx »

thanx for the info Gareth :-)
GroovyCarrot
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Post by GroovyCarrot »

More or less what I've got on mine - 8P tall ratio box from a mk2 1.3 in my mk2 1.0. Very drivable, motorway cruising is bliss and economy is much better.
Tahrey1043
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Post by Tahrey1043 »

Depends what the final drive is on your 4sp as to how different it may feel, but typically it'll be just as Gaz said. I've also done this, the first four gears are exactly the same (but worth it, as the old box was dying), and fifth is +20% higher, which makes more difference to the rpm and noise (...and available power) than you would think.

Personally I think it would have been more driveable but still nicely quiet had I been able either to track down the fabled 1.0 saloon box (same as an 8P, but has a slightly higher ratio final drive), or get a higher ratio 1.0 4speed and magically grow the expertise to swap the differentials over. 4th has always been slightly too long legged for maximum motorway thrashage, and 5th seems kinda stretched. Works far better than I feared it wouldn't, though.

(The final drive thing. Right. The 8P, and it would seem the majority of polo 4-speeds, have a 4.063 differential, which on the 4th gear we're looking at is 17.6mph/1000 - OK in a budget 1-litre as it gives a balance of speed and cruising ability in top, but it's not as good when you add another "economy" gear and 4th should become "top speed gear". Some 1-litres instead had a 4.267 diff, probably in cars sold in hilly areas or somesuch (and in the saloons!), giving 16.8/k, slightly better response and top-speed power, but more thrashy. This of course would also drag 5th down, so it's only like +15% to your current top, but still a nice bonus and blessed with slightly more stamina. EG You can get all the way up & down the M42 in 8P 5th in a 1-litre, but it's borderline in places, full throttle and it's dropping thru the 60s... on the higher diff it might at least hold somewhere near to 70 without you having to drop into 4th*)

The bigger headache is actually sourcing the part, and then doing the swap, if you haven't much help/tools to hand and you've never done it before. With the gracious and very detailed help of all the UKPoloites (and Porkalings) I got through it, but it was a bloody mare.
(esp. as I found my "8P" was a "CEG" - same ratios, different driveshaft flanges, needing to be transferred from the old box :shock:)

Oh, and though you probably won't need to change the linkage, DONT FORGET TO GET THE MOUNTS WITH THE 5SP BOX. They are utterly different! ^^^^^^^^ I know Gaz said but I can't stress it enough, as I was a spacker and forgot, blowing the whole operation for a couple weeks.

* This was with a custom chip on the ECU, though, which alters the engine characteristics... and on an engine that was slightly less run-in after heavy servicing than it is now. I will be able to report further regarding standard chip etc after tomorrow - I'm finally saying goodbye to the old dear, as my uncle takes it on as a "company car" for his currently Manchester-based business... and I have to drive it up there & get a lift back.
Gareth_GT_Hatch
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Post by Gareth_GT_Hatch »

you and your flanges tahrey! :lol: Should be ok on a late spec mk3 like a boulevard. It turns out that the saloon box has the same ratios as the mk2 golf 1.3 5-speed, code 8N. so that makes em a bit easier to track down, and with them being german, they might just last that bit longer...
Tahrey1043
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Post by Tahrey1043 »

damn, had i known, and had i been a bit earlier getting to the one that was sitting in loomses when i went... :)

makes it easier than hunting for some rare and easily confused polo A** code
you and your flanges
you knows it :D (i'm telling you man, no way was it gonna fit - but was perfect after i swapped 'em)
Tahrey1043
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Post by Tahrey1043 »

Edit - having trotted up the M6, along the A556, M62 and henceforth into darkest Mancuniville with it, the 'box has redeemed itself. 5th is a fair bit better with a slightly looser engine and a better crack of the whip. Think it wasn't quite run in before.

Still had to drop from 5th to 4th for speed's sake on some of the inclines, but it's not like 1/ I wasn't previously driving around with that gear as "top" anyway, 2/ it's a great chore, 3/ it accelerated worth a bean in 4th on those hills, neither.

On the flat, brilliant, much quieter, and moves along easy enough if you readjust your expectations.
Though, as unc is paranoid one of the Poles is going to flip out and rob it for a high-speed bender across to sheffs or something, I've reccomended he trains them to stick it in top and leave it there unless it shudders, as 80 is your top whack unless going downhill.
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