[E-Type] 2.88 differential

I’m considering swapping the 3.54 differential in my series II FHC to a 2.88
that I found on ebay.
Will that work OK with the 4.2 liter or maybe I don’t have enough power for
that low of a ratio. The lowest ratio offered for my car in 1969 was a 3.04

Thanks,
Paul__________________________________________________
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Besides the increased stress on the clutch, I don’t think over the
long run you would be happy. A 5-spee is the ideal thing for the e type.
LLoyd

Paul Ward wrote:>

I’m considering swapping the 3.54 differential in my series II FHC to a 2.88
that I found on ebay.
Will that work OK with the 4.2 liter or maybe I don’t have enough power for
that low of a ratio. The lowest ratio offered for my car in 1969 was a 3.04

Thanks,
Paul


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I have that ratio in my 3.8 OTS and quite like it. I wouldn’t worry about
the clutch, since last year when I changed from the moss box to an all
syncro I took my flywheel and clutch in to my machine shop for resurfacing,
and they commented it was one of the gentlest driven clutches they had seen.
I think it is a matter of driving style. Don’t forget that all the series 3
XJ6/12 that came to North America had this ratio and they are 1500 lbs heavier.
Acceleration off the line does suffer, but I can still leave most everything
behind if I put my foot down. I like the reduced revs and noise at highway
speed. 75 MPH is 2700 rpm, and the car could maintain that up a long 8%
grade without losing speed or downshifting. A side benefit is increased fuel
economy. After a long drive to the coast (700 mi) at 70 MPH I avaeraged 29
mpg. Can’t argue with that.

Try it, you might like it, and consider it as a cheaper alternative to a 5
speed, plus it keeps your cat “all Jaguar”

Craig
64 OTS

At 07:47 AM 30/07/00 -0700, you wrote:>I’m considering swapping the 3.54 differential in my series II FHC to a 2.88

that I found on ebay.
Will that work OK with the 4.2 liter or maybe I don’t have enough power for
that low of a ratio. The lowest ratio offered for my car in 1969 was a 3.04

Thanks,
Paul


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Paul, I agree with Lloyd. I think the 2.88 would be a bit too long-legged
unless you use your car almost exclusively on the interstates. I put a
3.31 in mine and the difference between it and the 3.54 is substantial.
Still, I was looking at the gearbox when it was apart and tried to figure
out how to get another gear in there. :slight_smile:

Jack Terrick
66 FHC

Paul Ward wrote:

I’m considering swapping the 3.54 differential in my series II FHC to a
2.88

that I found on ebay.
Will that work OK with the 4.2 liter or maybe I don’t have enough power for
that low of a ratio. The lowest ratio offered for my car in 1969 was a
3.04>>

Thanks,
Paul

Paul,

Like craig experiences, with that long differential you will get:

  • reduced rpm and engine live
  • increased mpg, decreased fuel use by the reduction of rpm. There is a
    minimum of cilinder fillling required to get the required gas exeplosion.
    The rangwe between minimum and maximum is much less then required for
    overcoming the airresistance, the main reason for engine power.

From mechanics: at 1/2 speed: 1/8 of power required, about 1/4 minimum fuel
burned.So a lot of fuel is trasfered you to heat the air. So if the final
reduction is increased by 23 %, you get a 23 % better mpg.

  • decreased acceleration or increased need to shift
    This is true is you maintain the same shifting behavior. If you shift more,
    you won’t lose that much as could be calculated. You will definitely lose
    a lot, but the enignes behavior due to the long stroke askes for a long
    final reduction and some more shifting. The power band of the jaguar is
    very wide, starting very low. Its running well from 1000-4500 rpm.

The cost of changing the final reduction is much cheaper than a 5 gear. I
would do it. If you don;'t like it you can change back. With this long
final you even have 2 options for a 5 gear box: a close ratio box, like
used for racing, and a 4+overdrive+original final, like used on regular cars.
Don’t forget: in Europe the standard final reduction is a 3.04, it is very
close to 2.88, 5 %. The engine is strong enough.

Wilko Pels
Wilko Pels
Amsterdam; The Netherlands
Opel Calibra: daily use
Mercedes 220 SE coupe; for sale with a repaired transmission

Experience with:
Daimler Conquest 54, Alfa 2000 GTV 73
Citroen CX 76, etc.

Echtenstein 815 tel +31-206003833
1103 AA Amsterdam fax +31-206001375
The Netherlands mobile +31-654378453
E-mail office@ppa.nl

Pels Production Advice is specialized in the process optimization for the
industry. The unique integrated approach of technical, logistical and
organizational processes is highly succesful formula.
A second branch of PPA is collecting government money from funding programs.

Hello Paul,

2.88 !! That’s a high ratio.

Mine is 3.07 which was standard in Australia. It’s very slow off the
mark, but OK for cruising.

I suggest you keep the 3.54 and fit a JT5 gearbox if you can afford it…

Clive Arnold
Brisbane, Australia
65 FHC, 1E20761----- Original Message -----
From: Paul Ward paulward99@yahoo.com
To: e-type@jag-lovers.org
Sent: Monday, July 31, 2000 12:47 AM
Subject: [E-Type] 2.88 differential

I’m considering swapping the 3.54 differential in my series II FHC to
a 2.88
that I found on ebay.
Will that work OK with the 4.2 liter or maybe I don’t have enough
power for
that low of a ratio. The lowest ratio offered for my car in 1969 was
a 3.04

Thanks,
Paul

Is there an easy way to determine what differential you have? I ask
because, it sure seems that my differential is not original, and I’m curious
as to what it is. In my 66 OTS when I’m going down the highway in fourth
gear, my tach reads half of my speed (i.e. 80 MPH = 4000 RPMs, 60 MPH =
3000) I haven’t pushed it yet, but it appears from this relationship that
my top end is about 100 MPH before redline. Top end should be around 150MPH
if I’m not mistaken.

So if this is a non-original differential, how can I determine what it is
and how difficult is it to change out?

Andrew Olson
66 OTS in RAINY Michigan-----Original Message-----
From: owner-e-type@jag-lovers.org [mailto:owner-e-type@jag-lovers.org]On
Behalf Of Clive Arnold
Sent: Monday, July 31, 2000 5:54 AM
To: e-type@jag-lovers.org
Subject: Re: [E-Type] 2.88 differential

Hello Paul,

2.88 !! That’s a high ratio.

Mine is 3.07 which was standard in Australia. It’s very slow off the
mark, but OK for cruising.

I suggest you keep the 3.54 and fit a JT5 gearbox if you can afford it…

Clive Arnold
Brisbane, Australia
65 FHC, 1E20761
----- Original Message -----
From: Paul Ward paulward99@yahoo.com
To: e-type@jag-lovers.org
Sent: Monday, July 31, 2000 12:47 AM
Subject: [E-Type] 2.88 differential

I’m considering swapping the 3.54 differential in my series II FHC to
a 2.88
that I found on ebay.
Will that work OK with the 4.2 liter or maybe I don’t have enough
power for
that low of a ratio. The lowest ratio offered for my car in 1969 was
a 3.04

Thanks,
Paul

check out www.5speeds.com, he has an online calculator where you can input
the various parameters ( rear ration, gear ration, tire size, etc…) to get
speed / RPMs

Pascal
72 2+2----- Original Message -----
From: “Andrew Olson” andrewolson@mediaone.net
To: e-type@jag-lovers.org
Sent: Monday, July 31, 2000 10:02 AM
Subject: RE: [E-Type] 2.88 differential

Is there an easy way to determine what differential you have? I ask
because, it sure seems that my differential is not original, and I’m
curious
as to what it is. In my 66 OTS when I’m going down the highway in fourth
gear, my tach reads half of my speed (i.e. 80 MPH = 4000 RPMs, 60 MPH =
3000) I haven’t pushed it yet, but it appears from this relationship that
my top end is about 100 MPH before redline. Top end should be around
150MPH
if I’m not mistaken.

So if this is a non-original differential, how can I determine what it is
and how difficult is it to change out?

Andrew Olson
66 OTS in RAINY Michigan

In message 001501bffad5$42b37b20$3df90fd2@globec.com.au, Clive Arnold
carnold@netspace.net.au writes

Hello Paul,

2.88 !! That’s a high ratio.

Mine is 3.07 which was standard in Australia. It’s very slow off the
mark, but OK for cruising.

I suggest you keep the 3.54 and fit a JT5 gearbox if you can afford it…

Clive Arnold
Brisbane, Australia
65 FHC, 1E20761
----- Original Message -----
From: Paul Ward paulward99@yahoo.com
To: e-type@jag-lovers.org
Sent: Monday, July 31, 2000 12:47 AM
Subject: [E-Type] 2.88 differential

I’m considering swapping the 3.54 differential in my series II FHC to
a 2.88
that I found on ebay.
Will that work OK with the 4.2 liter or maybe I don’t have enough
power for
that low of a ratio. The lowest ratio offered for my car in 1969 was
a 3.04

Thanks,
Paul

I changed my 3:54 for a 3:07 and consequently regret it from a
performance point of view. With the 3:54 the performance was sparkling.
Now I have the cruiser diff and it is great for motorway work. I am
definately going to revert back to a 3.54 with a 5 speed box when I can
afford it. (Paul Bjarnason was not as afraid as Mark Hicks when taken
for a blast!).

Don’t fit a 2.88, you’ll kill the car!
Angus Moss 65 OTS with sluggy 3.07 diff.

Is there an easy way to determine what differential you have? I ask
because, it sure seems that my differential is not original, and I’m
curious
as to what it is.

Andrew,
Standard in e-types sent to America was a 3.54 ratio differential. I’ll bet
that’s what you have. Actual top speed should be about 120 mph and your
tachometer or speedometer may be off a little bit.
If you can jack both rear wheels of the ground safely, mark the position of
the driveshaft and one rear wheel. If you rotate the driveshaft until the
rear wheel has made one revolution, the driveshaft will have turned 3.54
revolutions if you have a 3.54 ratio differential.
Paul— Andrew Olson andrewolson@mediaone.net wrote:


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IIRC someone was looking for this ratio which is now on eBay. naydayda
Larry______________________________________________________
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