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Building: Haynes roadster with Kawasaki ZZR1100
posted on 26/1/14 at 06:44 AM
Diesel??
Interesting idea put to me by a friend. Why not mate a tweaked vauxhall diesel to a Carlton gearbox and chuck the whole lot in a seven style
roadster. ??
After a bit of thought... Economy would be good, plenty of torque, revs would be down a bit but peeky enough if driven 'on' the turbo. But
what diff ratio would you need given a top rpm of say 4000 and a probable 1:1 ratio in top gear? If max speed wanted was say 120mph (let's face
it, any more and it's asking for trouble)
Yeah I know everyone's going to say 'engine will be heavy!' But so are pintos compared to bike engines. I thought it might be fun to
try something different.
Seem to remember the Weisel - a westfield V8 chassis with some sort of tweaked ford diesel in it - getting publicity maybe (gulp) 20 yrs go. I think
it span it's wheels in 5th or something ridiculous like that!
The closest I can think of was a MEV kit car fitted with a Focus TDCi engine, that was also in a magazine. But I spoke to the guy a year or so after
he'd finished, and while he did like the idea during the build, it didn't turn out as well in practice. The diesel just didn't suit
a lightweight car.
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Building: Built: Roadster, Exocet, Bertini, Now Something Di
posted on 26/1/14 at 09:19 AM
i reckon the current bmw 320 diesel engines would work well power delivery wise in a 7 they rev and drive more like a petrol than any other diesel i
have ever driven.
Anything With Tits or Wheels Will cost you MONEY!!
Haynes Roadster (Finished)
Exocet (Finished & Sold)
New Project (Started)
The weasel was in ppc a long time ago, a Vag 1.9 turbo motor, not sure what happened to it but it looked good to me. And, if I remember rightly it was
fast and did 90mpg.
I'm surprised none of the manufacturers took it up, after all they make good power and the torque would make a lightweight 7 fly!
quote:Originally posted by coozer
The weasel was in ppc a long time ago, a Vag 1.9 turbo motor, not sure what happened to it but it looked good to me. And, if I remember rightly it was
fast and did 90mpg....
I think we must be talking about a couple of different cars, here... the 'genuine' (Westfield factory-built) Weasel was powered by a
tweaked 1.8 litre Ford Sierra turbodiesel (modified by Richard Wilsher, from the standard engine's 75bhp to 120bhp... Garrett T3 turbo in place
of the standard T2, boost pressure raised from 12 to 20 psi and a Sierra Cosworth intercooler fitted, amongst other mods).
It wouldn't have been in PPC, 'cos PPC magazine didn't exist in 1992 (which was when it was built)... there was an article in Cars
and Car Conversions, I think, but the PPC article must have been a different car?
The Weasel wasn't that fast (0-60 in 6.6 seconds, 0-100 in a rather leisurely 24.5 seconds, standing 1/4 in 15.2 seconds and a top speed
of 108mph, all measured accurately by Autocar magazine at Millbrook, which suggests that spinning of wheels in 5th gear would be unlikely), though it
was pretty fuel efficient (compared to yer average contemporary petrol Westy on Webers!): average consumption of 58mpg, again measured by
Autocar. But if a VAG 1.9 TDi engine has been used, it certainly ought to be both quicker and more fuel-efficient than the factory Weasel.
The average fuel consumption was pretty impressive, given the state-of-the-art with diesel engines back then, but must surely have been limited by the
barn-door aerodynamics. The old Ford Sierra diesel is laughably primitive and inefficient by modern standards, so it makes one wonder what sort of
performance and economy you'd get from a current engine in a streamlined bodyshell like a Westfield Eleven or Sylva Phoenix.
With some spanner and screwdriver tuning it'll be in the area of 120bhp (around 200lb/ft). Bolt on a bigger turbo (T25, TD04) and you can see
160-180bhp (around 250lb/ft). Then fuel pump mods and you could see 200. Then there's propane injection, methanol/water injection, nitrous
I'm running about 120bhp at the moment, I've been parts collecting and I'll be putting on a bigger turbo and a supercharger soon,
along with a pi diff. £1 a litre veg oil, or cheaper used. Economy & parts prices are v important to me
what about a beetle fitted with a t2 Bus gearbox and 1.9 tdi engine ?
ignoring the weight bias (unless you turn it it over to make it mid engined) , chop the body off , porsche prototype bodywork replica and 100 mpg....
not bad for a cummuter car ...
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Building: Built: Roadster, Exocet, Bertini, Now Something Di
posted on 26/1/14 at 08:24 PM
quote:Originally posted by whitestu
Depends why you want the car. If you want it to be fun why on earth would you fit a diesel? If you are interested in economy then go for it.
Stu
i think what your actually saying is it wont make the right noise.
i have owned some seriously fun petrol cars and i must say the new 3 series derv is surprisingly very very good, some would say it almost sounds good
on full chat.
Anything With Tits or Wheels Will cost you MONEY!!
Haynes Roadster (Finished)
Exocet (Finished & Sold)
New Project (Started)
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Building: McSorley 7+4 with Rover V8 (See avatar for latest
posted on 26/1/14 at 10:18 PM
Got to be honest, I just don't see the point. IMHO, diesels only make sense in either a heavy vehicle where torque is important or for someone
doing very high mileage ( >15k per year) where the fuel savings make it worthwhile. Beyond those reasons, the only other reason I can think of is
the "because I can" type reason where it it simply a curiosity or itch that you want to scratch. Nothing wrong with that as a reason I
might add.
I say the above as someone who drives a BMW 535d as my commuting car (18k miles a year) and someone who has a Rover V8 engined locost. The V8 comes
into the "itch I want to scratch" territory because really the engine is not ideal for a locost if max performance was what I was after
due to weight, bulk and low specific power. However, the sound and feel makes up for it for me and it's still pretty fast. I was aware of the
pros and cons of my engine choice right from the start so I'm happy with the compromises.
In my opinion, the ideal engine for a seven is probably a high revving, VVTi normally aspirated all alloy petrol engine with a high degree of
traditional tuning applied (heads, cams, lightened and balanced etc). If you deviate from this theoretical ideal engine then you should have a good
reason to do so and be honest with yourself about those reasons from the start.
The diesel will be similar in many ways to my RV8. It will be relatively heavy, with loads of torque but not so much outright power (I've got
around 180BHP). However, my V8 power is instantly available due to no turbo. The diesel will be more economical but for the mileage a typical locost
does, this is unlikely to matter. The installation will be a lot more complex too due to high pressure injection, engine management and turbo etc.
It's all a series of compromises really whatever you decide so just make sure you've thought it all through carefully to avoid any
potential for disappointment later. In the end, when you've considered all the factors, the only opinion that matters is your own.
quote:Originally posted by craig1410 The installation will be a lot more complex too due to high pressure injection, engine management and
turbo etc.
Common rail would be a headache, and you can't run it on veg (unless you heat it up, twin tank etc). If going the mechanical injection route it
is far simpler. Lift pump is built into the injection pump so you just hook up a fuel line and a return line, no extra pump near the fuel tank, a
single 12v ignition to the fuel stop solenoid, no ECU and the turbo means the exhaust is just a single pipe, certainly easier than 8 pipes haha
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Building: Haynes roadster with Kawasaki ZZR1100
posted on 27/1/14 at 08:05 AM
Good points on all sides there guys, although complexity of installation doesn't come into it really.
I am a HGV mechanic anyway so diesels are the norm for me. My current build involves a zzr1100 bike engine and I've been sat with my head in my
hands on a couple of occasions wondering why I'm going that route.
It will get completed, no doubt about that and I'm hoping to be at Stoneleigh with it. As for the whole diesel idea.... Like I said in the
beginning, I know a guy who tunes diesels, remaps, etc and has a shed full of vauxhall diesel blocks, pumps etc. cheap.
As you all realise cheap is the attraction, it may not be the 'sexiest' or 'fastest' but for anyone who has just been
'knobbled' by the sneaky bastard camera van the emphasis on top speed is a little mute. Style and handling on the twisties, economy, and
the technical challenge of building it yourself is where I'm coming from.
It may be the next project, it may be a dream that will never be fulfilled. Maybe it's because I can/could. Possibly.....
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Building: Dax Rush - very, very slowly....
posted on 27/1/14 at 08:26 AM
quote:Originally posted by coozer
The weasel was in ppc a long time ago, a Vag 1.9 turbo motor, not sure what happened to it but it looked good to me. And, if I remember rightly it was
fast and did 90mpg.
I'm surprised none of the manufacturers took it up, after all they make good power and the torque would make a lightweight 7 fly!
yeah the PPC mag version of a weasel took one of the slightly older versions on the VAG 1.9 turbo (late 90's one off the top of my head) mainly
becase its a bit simpler than some of the later versions
he had it mated to a supra gearbox (mk3 ?) via some american VAG to Toyota adapter kit
quote:Originally posted by craig1410
Got to be honest, I just don't see the point. IMHO, diesels only make sense in either a heavy vehicle where torque is important or for someone
doing very high mileage ( >15k per year) where the fuel savings make it worthwhile. Beyond those reasons, the only other reason I can think of is
the "because I can" type reason where it it simply a curiosity or itch that you want to scratch. Nothing wrong with that as a reason I
might add.
I totally agree. The Locost (and any 7 style car) is a sports car, not something you use for lugging your familly around all year or taking stuff to
the local tip. Why ruin the potential of a sports car by fitting a low revving tractor engine. Not only do they stink, four pot diesels sound awful.
quote:Originally posted by MikeRJThe Locost (and any 7 style car) is a sports car...
But it could also be an incredibly fuel-efficient lightweight commuter that also happens to offer better performance and handling than the best
current hot hatches (at the price of all creature comforts, of course).
Is it a less valid design solution than the Renault Twizzy, with its 40 mile range and 0-60-never performance?
If the entire British kit-car industry could match Renault's production figures for the Twizzy, right now, it would be laughing...
What's all this nonsense about torque vs revs? Stick the right gearbox on it and you have a flat torque curve and little difference in
performance. You don't use flywheel torque to drive a car directly.
The only real issue, to me, would be noise. And weight. And difficulty tuning anything vaguely modern.
