|
Post by johnwp5bcoupe on Aug 21, 2011 6:49:25 GMT
Poll put forward by stevew to change the Differential to 2.8-1 from 3.54-1, for the benefit of lower revs and less fuel consumption.
Plus the price you would be prepared to pay? sensible answers on this one! as steve is talking to a diff supplier. Take into account the tooling costs, building (setting up) postage etc in the price.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Apr 1, 2012 21:44:39 GMT
I just bought the p5bcoup from ebay the SLEEPER with a poor gearbox that had a 4.5 litre upgrade to the tune of 30k from dak autos.God knows how they spent that much ,but its not the gearbox its the diff knocking so im looking for something myself. The wheels are off the very latest jensen ,not my favorit.and yes she revs to high with 14inch wheels and 55 low profile tyres .Seen the post with the cherokee wheels ,not bad .But what else fits chaps .Im more of a Track basher than a wheel man own www.tanks-alot.c.uk 100 or more Tanks and military vehicles.probably why i like the rover. Nick
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Apr 4, 2012 8:45:32 GMT
Been told a landrover/rangerover diff will fit and will gear it up any views on this ,i cany be the first to try.Got to do something quick mines clunking badly
|
|
|
Post by johnwp5bcoupe on Apr 4, 2012 14:14:39 GMT
Having played around with 4th gear see members section, IMHO the standard 3.5 with BW35 will struggle with the 2.8-1 diff under load conditions low speed, hills etc.
I think the LR ratio is something like 4.1-1 so you would be going the wrong way!
|
|
|
Post by colnerov on Apr 4, 2012 16:06:43 GMT
Hi, the Range Rover diff ratio is 3.54 the same as the P5b and is a direct swap.
Colin
|
|
|
Post by johnwp5bcoupe on Apr 4, 2012 16:25:49 GMT
I know the series 2 LR is 4.7-1 Colin, and the early RR was 3.54-1 but didn't the spline count change 10 to 24 on the later models?
|
|
|
Post by colnerov on Apr 4, 2012 19:14:14 GMT
Hi, yes John. But no clear cut off date and not for all. It depends on whether considered heavy duty or not I believe. If buying secondhand and they are usually 10 spline, if not vendor usually stresses the fact they are 24. Salisbury axles are 24 spline but not relevant in this case.
Colin
|
|
|
Post by stevew on May 2, 2012 16:05:32 GMT
Received an email out of the blue that crownwheel and pinions are now available 2.8 to 1 ratio to fit p5's from the supplier I was talking to when this poll began. He did want a minimum order so am a bit puzzled.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on May 8, 2012 14:07:05 GMT
Interesting wonder what the price will be .Happy with my joj though, seen it coming along expect it will be finished by the weekend . Pleased mine will have the semi floating powerlock diff from the 5.7 L jensen stops wheels spinning with the tuned 4.5L sdi engine i have and good in snow to. When i get mine back i will give some indication on the change in gearing when its motoring for everyone. Nick
|
|
|
Post by stevew on Jul 1, 2012 19:02:12 GMT
I took the opportunity today in taking some measurements with the standard 3.54 diff ratio to compare later when the axle is changed for one with a 2.8:1 Bizarrely my speedo is in direct comparison with the sat nav which makes easier. tyres are 215 70 15 with radius of 26.8 rolling circumference 84.2inches
MPH RPM 30 1650 40 2000 50 2400 60 2750 70 3150 zero too sixty ten seconds Obviously these rpm measurements are taken from the car tacho and are as acurate as possible
|
|
|
Post by johnwp5bcoupe on Jul 1, 2012 20:08:24 GMT
A near as dam it RPM measurement Steve on 185's is 2-1 ie 3500 at 70 and it should be linear sadly as the components age and they are not accurate anymore I had left over from my kart racing days a programmable standalone counter that picks up inductively from any lead so I could be sure of my findings for my project Good luck with the conversion
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Jul 2, 2012 14:48:22 GMT
|
|
|
Post by johnwp5bcoupe on Jul 2, 2012 15:12:22 GMT
That will do Richard that or straight SAE 90! Be prepared for the Smell
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Jul 2, 2012 15:36:48 GMT
Thanks John Smell from the old or the new?
|
|
|
Post by johnwp5bcoupe on Jul 2, 2012 15:42:35 GMT
The old Richard it stinks
|
|
|
Post by Baldrick on Jul 2, 2012 19:18:17 GMT
The new stinks too... And avoid getting on clothes as the smell is washing detergent proof!
|
|
|
Post by stevew on Jul 17, 2012 19:29:13 GMT
It's going in 2.8:1 Ratio crown wheel and pinion Actualy it's 2.8333333333333335 :1 And your correct EP 90 does stink, Iv'e had it up my nose all day, YUK
|
|
|
Post by stevew on Jul 18, 2012 20:12:27 GMT
3.5:1 CWP
SAT NAV MPH RPM SPEEDO READING 30 1650 30 40 2000 40 50 2400 50 60 2750 60 70 3150 70
2.8:1 CWP SAT NAV MPH RPM SPEEDO READING 30 1200 25 40 1250 35 50 2000 42 60 2220 50 70 2500 59
|
|
|
Post by johnwp5bcoupe on Jul 19, 2012 7:55:54 GMT
Looks ok Steve my only concern on a standard engine is under heavy load conditions I know from my own experience as I can duplicate changing the rear axle ratio that the gearbox changes very late and the strain on the gearbox/torque converter concerns me Perhaps Harvey the gearbox guru will come in on that angle
|
|
|
Post by enigmas on Jul 19, 2012 11:54:42 GMT
Nice set of gears, and the figures look convincing on paper but I'm with John on this one, a 2.8:1 ratio is too tall unless it's all freeway driving and there's a 351ci engine under the bonnet. A 3.5 litre engine will struggle. OZ P76 cars (4.4 litre engine ) came factory fitted with a 2.9:1 ratio but these had greater torque (longer stroke at 3.5") than the early Rover 3.5 V8. An overdrive gearbox would produce better all around performance and economy. Fitting the biggest cubic inch Rover motor available would make it viable www.roversd1.nl/sd1web/capacity.html
|
|
|
Post by harvey on Jul 19, 2012 14:00:14 GMT
I've said right from the moment the idea was first raised that I think that a diff ratio that high will lose everything it gains during high speed cruising by the loss of performance from a standstill. I haven't been bothered to calculate the overall gearing in first with both diff ratios, but I see it as though you will be pulling away with a ratio closer to second than first, and although Rovers always had second gear start it wasn't meant for quick getaways, rather for lazy driving, and other than where second might be better in poor traction, I can't see the point when you've got full auto mode anyway. It will be the converter taking the strain, and that will mean extra heat to get rid of.
|
|
|
Post by redsunbeam on Jul 19, 2012 15:55:45 GMT
Well done Steve. Is it much work to do? Has it made any noticable difference to the acceleration?
|
|
|
Post by Welsh Warlock on Jul 23, 2012 13:07:32 GMT
Very interested in this as I have a 3.9 engine built for torque by V8Developments and Harvery's friend rebuily my gearbox a couple of years ago.
My car is suffering from a rumble/vibration at 65+ mph which I suspect is either the propshaft or the dif.
I took the propshaft off last night and ran the car up to 100mph in the garage and the rumble didn't appear so it must be in the transmission. No apparnt lateral play in the UJ's (they are sloppy in their intended range of movement but no play as such). I do need to look at the centre bearing though as I ran out of time last night.
I have had the rear axle clunk a few time on pulling away and there is some play in it so.......
Can we find out the cost and some feedback on the performance from the standard engine with this plase.
|
|
|
Post by enigmas on Jul 23, 2012 22:43:36 GMT
Eastmidsrep, I'm not sure of the configuration of a 3.9 engine but generally longer stroke engines produce greater torque at a lower rpm. The 3. 5 is an oversquare short stroke engine. (ie. The bore is larger than the stroke) The 4.4 P76 is a 'square' engine...bore and stroke both at 3.5". Older British cars were traditionally undersquare (for tax reasons) producing lots of torque at low rpm. A big inch undersquare engine would be the go.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Aug 7, 2012 23:11:22 GMT
Well picked up the rover today with the jensen back axle fitted drove much better will check the rev to speed ratios with my sat nav over the next few days.Pulled out of the filling station a bit hard to check the limited slip diff, seem to do the job ,only one wheel span for about a second then it locked up nicely.the car seems responsive not at all sluggish .but it is 4.5L not 3.5L that may give it a bit more torc.can get more jensen axles with the disk brakes and calipers still attached.have one handy but the calipers are missing .my local garage will do the whole job for £500 thought it pretty reasonable,handbrake,reweld all the axle mounts,redo brakepipes fit a balancer and sort the prop.
|
|