Just my twopence worth
[Edited on 6/7/11 by Daddylonglegs]
Hi, I"m looking at putting a vag PD engine into a narrow bodied westfield. Have many people done a tdi kit car? and are they good news or not?
A PD engine with software will produce around 200 hp with shed loads of torque so should go like stink in a light westy.
Also what gear box would be best to mate it to and who would do adapter plates etc? It currently has a Quaife type 9 box in..
Any input welcome cheers james
Just a thought... would a shed load of low down torque, and a low rev range be a good thing in a lightweight sports car? i would have thought it would be trying to catch you out all the time. especially if the road surface is damp, or loose
I think this is a good idea because I own a PD 150bhp golf and the engine is awesome. Goes like stink and does 55mpg. However the traction control
on my Golf kicks in all the time if you boot it. It'll kick in at 35mph if its a bit damp out.
Sounds like a tractor as well.
Torque is fine it's the delivery of it that can cause problems, perhaps boost limiting in the lower gears.
Quaife type 9 should be ok
Diff ratio will need to be higher as revs run out at 4,500 you need to run a gear ratio program to work out the best combination of gears, diff, tyres
was there not a PPC Mareg feature on this
regards
Agriv8
quote:
Originally posted by bhp
are they good news or not?
I tend to agree with Davey D and Snapper, and Irony says that the traction control kicks in at around 35mph on a wet day. Bear in mind the weight
difference, a Golf probably weighs in at around 1.25 tonnes so on a Westy?
Just my twopence worth
[Edited on 6/7/11 by Daddylonglegs]
quote:
Originally posted by Agriv8
was there not a PPC Mareg feature on this
Personally I think a diesel is totally wrong in a car like this, though I´m not a diesel fan generally unless in a van.
Stu
quote:
Originally posted by whitestu
Personally I think a diesel is totally wrong in a car like this, though I´m not a diesel fan generally unless in a van.
Stu
quote:
I disagree. I think that in the future more and more kitcars will be oil burners! With the fuel prices still soaring I think we'll start to people building cars for a economical commuter/fun car. Just look at the 'budget' kits you can buy these days. How long before a kitcar manufacturer starts using a diesel to promote budget build costs and budget running costs? Just bring your ear defenders.
Depends on your outlook on these things. I drive a diesel daily and whilst its a 'sporty diesel' it still bores the hell out of me, therefore whatever I drive at the weekend needs to be fun - couldnt care less about the cost of running it.
How many people do you know who build a kit car for econonmy and commuting ? I personally dont know of any. The original 7 was all about low weight
coupled with modest power for a great driving experience, I cant imagine a VW derv burner clattering in the front end delivering that. I am not
against diesel power, I own an A3 2.0 tdi but i cnat imagine ever putting that engine in a 7, its just plain wrong. Of course all of this is just my
own opinion.
quote:
Originally posted by Irony
quote:
Originally posted by whitestu
Personally I think a diesel is totally wrong in a car like this, though I´m not a diesel fan generally unless in a van.
Stu
I disagree. I think that in the future more and more kitcars will be oil burners! With the fuel prices still soaring I think we'll start to people building cars for a economical commuter/fun car. Just look at the 'budget' kits you can buy these days. How long before a kitcar manufacturer starts using a diesel to promote budget build costs and budget running costs? Just bring your ear defenders.
is it wrong to put a diesel in a racing car then, for example?
I think that diesel engines in race cars has got a lot to do with marketing as much as anything else, although a racing diese engine does offer
"slightly" better fuel economy.
Given the choice I prefer the sniff of petrol any day.
may well be marketing, but they've winning races too. 15 years ago, yeah, diesels were noisy, smoky, and underpowered for cars, these days i
don't think there's anything in it. they're not even that noisy anymore.
i certainly wouldn't say its 'wrong' its an interesting choice, and good to see people breaking away from the usual
if its geared properly why should the torque output of the engine be a problem?
Personally I'd prefer something a bit more revvy, but I have seen a couple of diesel 7s for sale over the years. I do wonder , like some others,
if the torque delivery will mean the wheels spin a lot.
Do you know how much the engine weighs? Might affect the balance of the car.
Although the engine block isn't that big, I wonder about the packaging of the turbo/intercooler/Cat etc in the narrow bodied westfield.
Will the ECU work without all the emissions guff, or would you transfer that too? Can it be reprogrammed to get rid of all that stuff, or is there a
3rd party reprogrammable one available?
If you havent measured one, it might be a good idea to find the weight/height/width etc beore going any further.
Regards
Hugh
A couple of points.
The original 7 had a Ford sidevalve engine, among others of the time. These not so little engines probably did fewer revs than the vw diesel, and
weighed as much or more, and out out 1/3 of the power. With that comparison, the modern diesel is a major upgrade. Try picking up the flywheel off a
Ford sidevalve. You'll need a hernia brace!
Diesel racecars exploit a couple of rule loopholes which give them a significant advantage when given shedloads of boost, and maybe not so much boost
with the modern engines. The diesel gets its economy from being a lean burn engine by nature and design, and gets its power/torque from very high
compression(compared to petrol) and long stroke(relatively), and a higher calorific value fuel. All adds up to a big plus when given extra oomph with
boost. It is significant that BTCC diesels are now being reigned back with reduced boost limits.
Would I put a modern diesel in a racecar? No, they just sound wrong. You can't beat a big V8 at full song for sound, or a BDA!
Cheers,
Nev.
Its not the torque it is the delivery that is the problem.
In a heavy tin top a 140 bhp petrol and a 140bhp turbo diesel will give roughly the same performance -- the diesel probably more useful for 40 to
70 overtaking.
But put them in a very light sports car and a free revving petrol engine will win hands down.
quote:
Originally posted by britishtrident
Its not the torque it is the delivery that is the problem.
In a heavy tin top a 140 bhp petrol and a 140bhp turbo diesel will give roughly the same performance -- the diesel probably more useful for 40 to 70 overtaking.
But put them in a very light sports car and a free revving petrol engine will win hands down.
quote:
Originally posted by Irony
quote:
Originally posted by britishtrident
Its not the torque it is the delivery that is the problem.
In a heavy tin top a 140 bhp petrol and a 140bhp turbo diesel will give roughly the same performance -- the diesel probably more useful for 40 to 70 overtaking.
But put them in a very light sports car and a free revving petrol engine will win hands down.
Why?
quote:
Originally posted by Irony
Why?
I like revvy engines, but I can also see the appeal of torque from low revs. The engine in my Rush (Honda F20C) really starts to pick up when a lot of
other 2.0l engines would start bumping the red-line. Can't see the appeal of these low-revving Zetecs or Vauxhalls... (It's all
relative)
However, there is a certain appeal riding in a low-revving (to me, at any rate!), high torque, V8 powered 7. Put your foot down in any gear and it
just pulls like a train! My Astra CDTI does pretty well on that score, too.
I like the idea of trying anything unusual - surely one of the appealing things about building your own car. I think the main down-side would be the
noise - diesels just don't tend to sound exciting, and maybe the smoke when booting it. Perhaps you could reduce the latter with some clever
mapping...
In terms of gearing, perhaps there may be some lessons to be picked up from those running V8s in 7s. There's a good number in the Dax Rush
community, for starters.
quote:
Originally posted by dlatch
because you don't need huge torque to move a light weight kitcar
the theory on this is already proven by how effective BEC powered kits are on the performance stakes. to make use of the diesel powerband you would need it geared right up so you pull longer gears making use of the torque.
i love diesels for tintops and vans the powerband is perfect for road driving while still getting great mpg.
i would also say even though a tdi kitcar is possibly pointless thats no reason not to do it
on track and upto speed it would have great performance if you can get the ratios right. i do suspect the torque to kill any of the old ford running gear though (T9 and english axle)
I think someone should get off their arse and actually do this so next time the topic comes up we wont all have to guess about how good or bad it will
be By 'do this' I mean put a modern TDI engine with all it's electrickery in a kit car BTW not the Isuzu/GM engine which only needs
about the same amount of wiring as an XFlow to get running and which are pretty much the only diesel engines to have been put in a kit car so far to
my knowledge
Personally I actually think it might be rather good if done properly - Saab Turbo engines have a very similar power delivery/torque to a diesel after
all but no one dismisses them as quickly.........
At Newark there was a 7 just leaving as I spotted the diesel rattle coming from it.
It was yellow and it had some sticker on the back saying something about running on chip fat.
As I say, it was just leaving so didn't see anything of it except the rear end.
It didn't sound like a "new generation" engine though, decidedly agricultural sounding
I've thought about this a lot , but can't be arsed to do it , I think it could be really good , I accept the theories over weight and not
needing loads of torque etc , but I still think the mid useable driving range torque/acceleration would be amazing, I have driven a Focus 1.8 sport
diesel and it is incredibly responsive and crisp.
Although I'm not sure how an Escort axle would cope................
I always thought that the engine etc from a 320d BMW would be the way forward.
some strong opinions from people who have never driven a diesel kit car.
i have one. its cool. but its a mid engined Rocket so traction is not an issue. definately not suited to the 7 style car.
quote:
Originally posted by Irony
I think this is a good idea because I own a PD 150bhp golf and the engine is awesome. Goes like stink
quote:
My friends supercharged MG ZT V8 producing 400 bhp is enormously quick, but doesn't feel it at all
quote:
Originally posted by D Beddows
quote:
My friends supercharged MG ZT V8 producing 400 bhp is enormously quick, but doesn't feel it at all
I'll be honest, I've never seen the point of having an enormously fast road car that doesn't 'feel' quick......... a slower one that feels quick (for whatever reason) is always ultimately much more fun surely!
quote:
quote:
--------------------------------------------------------------------------------
Originally posted by D Beddows
quote:
--------------------------------------------------------------------------------
My friends supercharged MG ZT V8 producing 400 bhp is enormously quick, but doesn't feel it at all
--------------------------------------------------------------------------------
I'll be honest, I've never seen the point of having an enormously fast road car that doesn't 'feel' quick......... a slower one that feels quick (for whatever reason) is always ultimately much more fun surely!
--------------------------------------------------------------------------------
This q comes along every now and again and the torque issue always come up.
Torque effect can be reduced by using a lower ratio diff. This also has the effect of increasing a diesel engines speed range in each gear.
I think it's a fab idea to stick a diesel engine in. If you soundproof the engine bay a bit and have a reasonably open exhaust, they sound great.
And who really wouldn't want to get 50 mpg when on a run at a constant speed (ie when driving normally in traffic).
Many years ago we had a auto 827 Vitesse and I was following an old 218 diesel. I had trouble catching him from about 50 - 80m then I got past. That
was 14 years ago, and I still wonder why I bother with petrol
ATB
Simon
Might sound obvious but use a modern diesel engine, adapt the stock ECU fit speed sencors to the hubs and keep traction control. I honestly think (and
I haven’t done it like almost all those commenting on this thread) the “Diesel won’t work in a light car” rhetoric is no different to the “200hp is
the absolute limit for FWD” argument that used to exist.
Basically these things are often quoted, often based of the musings of some long retired ‘so called’ sage of motorsport but generally quoted by people
who haven’t tried things out for them selves.
Like most I don’t know what a 7 on diesel will be like to drive but my best guess is if it is done well and remember many petrol variants are not! I
believe it will be super drivable, easy to drive and forgiving like almost all diesels I’ve ever driven
[Edited on 6/7/11 by orton1966]
I really never understand why people go on so much about the 'impressive' torque figures of diesel engines?? They are flywheel torque
figures and so meaningless without taking the revs/gearing into account. Unless you want a top speed of about 80mph you need considerably higher
gearing in your 150bhp/200lbft/5000rpm diesel than in your 150bhp/150lbft/7500rpm petrol car. So as far as the wheels are concerned that big diesel
torque number is gone thanks to the gearing. All that's really changed significantly is the delivery. Diesel delivery favours lazy driving where
you want to just prod the throttle pedal to go without being arsed to change down a gear or two. The peakier petrol delivery suits a more involved
spirited driving style where you ring out the engine and use the gears to get the best out of it, a bike engine takes that to the extreme. One of
those characteristics suits dull shopping/commuting boxes and commercial vehicles, one of them suits fun toy cars - guess which is which Then
there's the god-awful sound. Why anyone would go to all the effort of building a unique car purely for pleasure and even consider a diesel I
cannot comprehend!