iwbunting
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| posted on 22/4/04 at 09:11 PM |
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Rover V8/Jag Irs Locost & SVA
Has anyone come across an SVA'd locost with Rover V8 & Jag Irs combination.I am contemplating a complete build using these components.Whilst
i am a novice with locosts i have past experience of designing and building VW & motorcycle powered trikes.Can anyone help ???
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britishtrident
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| posted on 23/4/04 at 12:26 PM |
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Jag IRS rally isn't a good idea it is just much much too heavy. A Sierra 2.8 V6 diff is more suitable and more than adequate for a Rover V8
which isn't really all that powerful by modern standards.
The Rover V8 is a light for a V8 engine it is not a light engine by Locost standards also installing it in a Locost style chassis means leaving the
very vital main diagonal brace out of the engine bay, some of the stiffness can be put in by adding two shorter diagonal braces across the rear
corners of the engine bay but this still produces a less stiff chassis than the original.
[Edited on 23/4/04 by britishtrident]
[Edited on 23/4/04 by britishtrident]
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craig1410
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| posted on 23/4/04 at 11:21 PM |
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iwbunting,
Take a look at my website for some details of how I fitted the Rover V8 engine along with a de-dion rear axle and Sierra diff. To put some figures
against the comparitive weights of engines refer to the following thread:
http://locostbuilders.co.uk/viewthread.php?tid=12640
Here is a summary of the findings thanks to ChrisG:
Pinto (sierra 2.0 inj)...................135 kilos (295 Lbs)
Crossflow (Escort HCS1.6 carb)............109 kilo's(239Lbs)
Rover v8(Range rover inj)...........160 Kilo's(324 Lbs)
Toyota 4Age (MR2 inj)...............103kilo's(225 Lbs)
Rover K series (216 inj)..............100Kilo's(220 Lbs)
Ford Zetec(escort inj)..................105 Kilo's(231 Lbs)
As you can see there is only 60Kg's between heaviest and lightest which is a small price to pay for a nice V8 burble don't you agree??
You can also stiffen the chassis quite effectively to replace the stiffness taken away by the loss of tube "R" from the book design so
with all due respect to BritishTrident, don't be put off for this reason. The book chassis is by no means perfect and regardless of which engine
you choose it is worth making a few mods. Check out postings by a guy called Cymtriks as he has performed finite element analysis on several mods
which are worth considering.
Cheers,
Craig.
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britishtrident
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| posted on 24/4/04 at 12:00 PM |
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Rover K16 is 175 lbs -- the 220 quoted must be with all ancillaries, I have lifted lift a naked k16 with one hand. it is that light about the same
weight as a Rootes Imp engine.
Don't forget with a V8 you have bigger ancillaries in fact everthing is bigger, raddiator battery starter alternator, fuel tank, more oil and
water and twice the exhaust system.
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craig1410
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| posted on 24/4/04 at 01:14 PM |
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If you look at the thread I was referring to you will see that the weights were all taken from cars in a scrapyard on the same day using a digital
scale with fluids drained but all ancillaries still attached. The only ancillary removed was the starter motor, presumably to allow the gearbox to be
separated easier.
This even included the pair of heavy cast exhaust manifolds on the RV8 which I weighed myself and found to be 16Kg's. You could easily save a
few Kg's by using tubular manifolds even though you obviously still need two of them.
As for the heavier ancillaries, well that obviously depends on what you decide to use. I am using an aluminium and plastic radiator from a VW Passat
1.8 which other's have said works fine with the RV8 and it fits nicely within my nosecone. It is as light as a feather. The alternator is the
same physical size, shape and weight as that from a Mini (old mini that is) so I don't see that as a problem and I intend to use a standard 36
Amp/Hour battery as a Locost has very light electrical loading and virtually all of the charge from the alternator will be available for the battery.
As long as you use a good quality battery then the starting power is perfectly adequate without having to use a larger battery.
How much fuel you carry is entirely open. Clearly a 200BHP V8 will consume more fuel than a little 1.4 K-series but then again it has twice as much
power! Personally I intend to go for about 40 litres fuel capacity which is only about 5 litres more than the book design and thus about 4.5
Kg's. That should give me close to 250 miles range which is perfectly adequate.
Cheers,
Craig.
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Bob C
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| posted on 24/4/04 at 05:28 PM |
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3.5 RV8 in 1 ton car does 20.5mpg with 25mph/1000rev gearing in top.
4.6 RV8 in same car does 20mpg with 34 mph/1000rev gearing in top but other ratios same. My car so these figures are gospel.
I wouldn't expect 250miles range! see how you get on!
Cheers
Bob
PS agree jag irs looks weighty but no top wishbone & inboard brakes. Should be straightforward to compare unsprung weight with escort axle? Has
this been done already? Can you get small enough wheels to fit the studs?
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britishtrident
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| posted on 24/4/04 at 06:53 PM |
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quote:
Originally posted by Bob C
snip
PS agree jag irs looks weighty but no top wishbone & inboard brakes. Should be straightforward to compare unsprung weight with escort axle? Has
this been done already? Can you get small enough wheels to fit the studs?
Re Jag axle it takes 5+ strong guys to lift one out a van --- I have done enough major work on Jags to know, to put even a narrow E type rear
assembly back in normaly involves 3 guys and 3 trolley jacks. In contrast I move my spare english axle around my workshop workshop by myself very
easily .
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britishtrident
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| posted on 24/4/04 at 06:54 PM |
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quote:
Originally posted by Bob C
snip
PS agree jag irs looks weighty but no top wishbone & inboard brakes. Should be straightforward to compare unsprung weight with escort axle? Has
this been done already? Can you get small enough wheels to fit the studs?
Re Jag axle it takes 5+ strong guys to lift one out a van --- I have done enough major work on Jags to know, to put even a narrow E type rear
assembly back in normaly involves 3 guys and 3 trolley jacks. In contrast I move my spare english axle around my workshop workshop by myself very
easily .
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craig1410
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| posted on 24/4/04 at 08:03 PM |
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Bob,
My Dad ran two SD1 V8's (an "R" reg and a "V" reg) which he owned from new. He could get 25MPG around town and rural B
roads and 30MPG on a 200 mile+ run. This was in a 1.5 ton car with 1970's tyre technology.
I don't expect to get twice the MPG because my car is half the weight but I do expect a little bit of improvement. Clearly at higher speeds the
aerodynamics of the Locost will be poorer than the SD1 (not by much though) so MPG's at 75MPH will be less impressive but at 56MPH I'd
expect better figures than the SD1 and so may approach 28MPG on a cruise.
Before you ask, my Dad is an ex club/national level rally driver and so he didn't just pootle around at a snail's pace either...
We'll see and I stand ready to eat my words... By the way, my engine is only a standard SD1 155BHP engine although with free-flowing exhausts
and K&N filters I expect it to put out closer to 170BHP.
Cheers,
Craig.
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NS Dev
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| posted on 25/4/04 at 08:38 AM |
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Whilst I agree with BriotishTrident on the Jag IRS weight problem (it IS heavy, the diff alone being extremely heavy duty, well it is designed for
300+hp and a V12 so....)
Craig is dead right that the Rover is light, the figures he quotes are certainly with ancilliaries, and the Rover standard starter and alternator etc
are very heavy too! The bare engine is considerably less than 160kgs.
By the highly sciantific method of getting them on and off trailers on my own, the Rover V8 and Pinto are very similar to maneouvre!!!
Think I'd go for Craig's weights though, bit more scientific!!
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iwbunting
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| posted on 25/4/04 at 08:26 PM |
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Rover V8/ Jag IRS
Having read all the response to my original post i have come to the conclusion that i can stick with the V8 and go for a De-Dion instead of Jag
Irs.Thanks to craig chamberlain and the information on his website,this must be the way to go.
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craig1410
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| posted on 25/4/04 at 10:52 PM |
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Ian,
Thanks, as I said in reply to your email you should check out GTS Tuning for details of their excellent de-dion
axle kit although be aware that this kit is currently designed to fit a standard width chassis and you will probably need to make your chassis
+4" wider to accommodate the V8. Check out Jim McSorley's website for plans to build the
McSorley 7+4 which is simply a book locost with all the mods required to give it 4" more width. He also corrects some of the book mistakes and
gives you the angles for all the cuts.
NS Dev,
Thanks for the vote of confidence in "my" weights but please let me re-iterate that these were taken from a recent exercise by ChrisG. I
don't want to take credit for his work...
This was one of the most objective exercises I am aware of and should be taken as pretty authoritative unless someone knows different IMO. I was
surprised to see the RV8 slightly heavier than the Pinto as I too thought it was the other way around. There's not much in it though and the
performance potential of the RV8 far outstrips the Pinto unless of course we are talking Cossie.
I know what you mean about the RV8 feeling light. It always seems to me to be lighter than old mini engines which I used to lug around. I think it is
the fact that it is less dense than an engine with an iron block which makes it seem lighter. I can certainly "walk" the engine on my own
and I was able to fit the engine single handed which involved a bit of pushing and shoving to get the engine into my little engine bay and onto the
gearbox splines...
Cheers,
Craig.
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Simon
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| posted on 28/4/04 at 10:55 PM |
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"Re Jag axle it takes 5+ strong guys to lift one out a van --- I have done enough major work on Jags to know, to put even a narrow E type rear
assembly back in normaly involves 3 guys and 3 trolley jacks. In contrast I move my spare english axle around my workshop workshop by myself very
easily"
I must've been incredibly strong in my youth, cos I hoiked a complete JAG IRS unit (diff/cage/shafts/bones/uprights) out of the boot of my Viva
(which was to be recipient of same but never was - short story but still ain't telling!!)
Craig,
I think you are being very pessimistic on the fuel consumption. My (injected) 3.9RR returned 28mpg (full tank home to Brighton and back - approx 100
miles, then refilled) and I wasn't hanging around
Most fuel is used getting the weight (mass) moving ie acceleration, and ours will a) not have much mass, and b) get to speed very quickly.
With a reasonably low diff (3.38) cruise (ie most of the time following other traffic ) will mean low revs, and with the torque available, little
reason to change down, other than to change volumeD).
ATB
Simon
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Bob C
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| posted on 29/4/04 at 09:19 AM |
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nah - it's me being pessimistic about fuel consumption. What can I say - it's what my V8 mx5 does on cheshire lanes. Admittedly
that's with a lumpy cam and 500cfm edelbrock 4 barrel carb - I know the original SUs would give much better fuelling at low flows. I have a rack
of 44IDFs to pop on the 4.6 when the gearbox is fixed - I'm sure that'll do wonders for the mpg as well........
Cheers
Bob C
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