Southern Rolling Road & Tech Day - end Feb/beg. Mar

[Vanny]

RR day was good, drive home was fantastic!

Seriously though, that was by far the most productive day out i've had with the car for a long, long time. Not only am I considerably more confident that the car isn't just going to spit its guts out, i'm gob smacked at how many horses it still has. I was expecting 140bhp at the engine.

Some pictures;

Hillarys valver on the rollers



Jas off to her exam;



Action shot;



TD Draws a crowd



The result;

<-- Click me

Total of 160bhp at the engine, which i think the Doc must take credit for, given his fanatical engine building skills.

Great to see the range of torque curves from the TD's as well, all though the results are similar for peak, the way they're giving out power is so different between the three.


My thanks to Kitch for running the event and the loan of the 4 poster. Resetting the suspension height has worked absolute bloody wonders already! Just coming out of Southways, it took the speed bumps as a valver should rather than just crashing into them head on!

[Caffiend]

Breeding Horsies, excellent, there's hope for our cars then

OBLIG: I was actually planning to bring the excess to the CCC National in July for the BBQ.

[RobC]

Just want to echo everyone else's thanks! Had a great drive back and what a difference a fully functioning rear ARB makes..

Thank you kindly to Kitch for hosting, and to Vanny for expert suspension faffing.

Great to meet you all.

Rob.

[Vanny]

and to Vanny for expert suspension faffing

Rob.

You do realise that I was just practising before doing mine?

[saintjamesy89]

Another thanks post Cheers Kitch for being a wonderful host, and was nice to meet you. It was also nice to meet a few new faces (Rob, and Vanny's lady whom I have either not remembered or not known in the first place, her name. It was nice to meet her in any case!) and see some known ones again.

I was pleased to find that my TXD was putting out 90.45 bhp at the flywheel (corrected figure) and 70.3bhp at the wheels (measured), these are an average of the two runs it had, which is a significant loss of power I think! It lost the most power out of the three TD's and was the second most powerful, although flatter at low revs and more boosty than John's TZD estate (Jaba). Still respectable for 20 year old diesel though I think. Even though it lost the power (and smoke) contest to Sandre, it sounded the best of the diesels IMO, partly due to the shot back box

I'm glad it's standard, which I wasn't expecting, as it's got much more potential. That is, if I decide to keep it.

Thanks again Kitch and Southway's.

[Kitch]

Thanks to all who came down (and sorry again that Mike expired on route!) Was exactly the sort of event I'd pictured it could be too, with like-minded people all enjoying a spot of noise and drama

Was a first for me on any sort of dyno-day too; of all the cars we strapped on, not one of them disgraced themselves in terms of their performance. Normally you have one or two people end up going home, with tails between legs. But not in this case....all the cars performed sterlingly I thought. Very little needed in the way of head-scratching either....I was expecting tinkering to be in order, but none was needed!

Only slight disappointment of the day for me was purely the fact we didn't have much variety in the way of models - it was either a red 16v, or a green TD Great for comparison though, but could have been good to have a 14, a 16, a 19D etc. But hey ho, maybe another time?

Just before I left, I had a play with some of the graphs and changed some things around to demonstrate some stuff.....


1) Here are the TD results of the day. I've changed the correction factor over to DIN; all your tests were corrected using SAE fomulas, which is now the worldwide standard. Back in the days of the BX, DIN was the standard used (90bhp....sometimes you see an 88bhp figure; this is SAE). So for comparison to book figures, DIN can be a bit more fun. Like I said though, the only figure that is a fact here is the output at the wheels of either horsepower, or torque. The engine corrected value is the best one to use for flywheel (at the engine) figures, which are used in the brochures. The engine measured value isn't really worth looking at.
We can see Jaba and Tom's TDs were both running happily enough here. Jaba's had the better spread of torque so I would guess is the more flexible car to drive. Tom's had more of a lazy spot at the lower end, before the turbo woke up! There was very little to call it between the two and both cars seemed to be in good health. Sandre's came to the party with something more though! Oil burner wizards (Doc?) might want to take a look at it, but for a car that's supposed standard, the turbo surge was much more pronounced as well as being louder! It also clagged like a Class 55 loco above 3500rpm So if we're running on DIN figures, here, Sandre's gone home with 7bhp more than it left France with!


2) Here we have the same again using DIN figures (which is why you guys have all gained some more geegees), but for the 16v'ers. Again no issues to speak of; in fact it was a great day for me because I'd dyno'd three different BX 16v cars up to this morning and mine (BAH) was the only one that was running on the money. I was worried the BX 16v is one of those cars that never makes the claimed power, and that mine was flukishly running better.
But no, today we had three more 16valvers along which were running so closely it was unreal. As Hilary pointed out, no body knows the history of their cars from new. I found it amazing that they were all so closely matched, and testement to the fact the XU9J4 is (contracting the hyper-bole about them being highly-strung and fragile) a pretty sturdy unit. Both Vanny and Rob posted freakishly similar figures (though both were 3-row ECU cars) and both hit the limiter before they stopped dishing out the power (worth pointing out Rob's graph is off-course as he had a shorter 3rd and 4th gear set fitted so his terminal speed is lower). Hilary's came back with similar numbers again, but suffered less of the 3k rev drop-off that seems to befall the 16v. Mine posted similar figures to the runs I did last year, being down 2 or 3bhp but I was quite happy as it had literally come out of storage and still had 3 month old 95RON sitting in the fuel tank

[Kitch]

3) I also decided to have a play with the graphs here. This is an overlay of Tom's TXD Turbo and Vanny's 16v. I wanted more variety of BX there as I could have filled the graph with the different variants, which I thought would be interesting, but this was still good to look at for me as the cars are so completely different.
The graph has had to be plotted using road speed rather than RPM, but it's easy to see the differences right away (TD in black, 16v in red). The torque produced at the engine is greater on the TD, and much earlier on, but it starts to tail off again as the revs climb. On the petrol car, the torque kicks in (eventually) but hangs on as the engine speed increases. It's a bit of an extreme comparison as the 16v is producing twice the power of the TD at the driven wheels.


4) This, I think, is the most interesting comparison. It's the same runs again, but this time we're using the torque produced at the WHEELS not the flywheel (the dyno calculates all the figures starting with this figure). Straight away we can see a massive change - where the TD had an advantage over the 16v before in terms of sheer pulling power (at the flywheel), the tables are turned when we're measuring what the actually put onto the tarmac. In other words, how much rotational torque is produced at the wheels. This time, the 16v is miles ahead, which might surprise people. When you think about it, it's perfectly rational. This is the best figure you can physically view for seeing how fast a car is (or how well it accelerates anyway) on paper, without driving it. It's completely different to the engine figures, because the gearing between the engine and the wheels is different; put in very basic terms (because I am very basic!), the 16v has much shorter (and therefore easier to turn) gears. Specifically, we're talking about 4th gear. The diesel needs a taller gear because it doesn't rev as high; if it had the gearing of the 16v, it would accelerate a shedload faster than they do now, but only for a very brief time as the torque/power bands are narrower (you'd probably top out at 30mph in 2nd or something ).
The graph also highlights how well the diesel displaces all its energy early on, but more surprisingly the fact the 16v has much more torque right from the word go. If only I could enable a function to measure fuel consumption during these tests
So it would have been nice to include something like a 14, a 19D, an 8v GTi etc, purely for these experiments to show how the different models of the BX use their power at the wheels. You may well learn more surprising stuff, like an n/a diesel might have less grunt than a 14 petrol, or a 19 petrol might be weaker than a TD.

There are probably a few errors in that as I'm quite tired now, but hopefully it all makes sense. Cheers again to everyone who came along. There were no duffers in this bunch of cars, they're all running great so credit where credit's due!

[Kitch]

RR day was good, drive home was fantastic!

Seriously though, that was by far the most productive day out i've had with the car for a long, long time. Not only am I considerably more confident that the car isn't just going to spit its guts out, i'm gob smacked at how many horses it still has. I was expecting 140bhp at the engine.

The result;

<-- Click me

Total of 160bhp at the engine, which i think the Doc must take credit for, given his fanatical engine building skills.

Great to see the range of torque curves from the TD's as well, all though the results are similar for peak, the way they're giving out power is so different between the three.


My thanks to Kitch for running the event and the loan of the 4 poster. Resetting the suspension height has worked absolute bloody wonders already! Just coming out of Southways, it took the speed bumps as a valver should rather than just crashing into them head on!

*Cough* that's 150bhp mate *cough*


Cheers for coming down though. The old girl obviously heard all the negative press you were giving it and decided to show you up by running way better than you'd expected

[MULLEY]

It would be interesting to know what turbo's are fitted to see if that can account for any differences as well as how many miles each car has under its belt. From the data it would seem the older the TD car the more power it has over its younger one, possibly to do with emission standards changing? It could of course just be pure co-incidence? Sandre's may have been fiddled with perhaps bearing in mind the extra smoke being noticed? Very interesting stuff, hopefully there will be another RR day & some more of us can turn up & see what happens

[Caffiend]

There was some discussion as to whether mine had been tweaked - inconclusive, nothing on service history beyond fixing a couple of emissions failures on past MOTs, also nothing to indicate whether it's had any injection components replaced, or pump overhaul/replace. Comparing notes on the pumps, mine's a Bosch, Tom's is a Lucas and Jaba's was something else (forget what sorry ). Next time I speak to Rob M, I'll ask him if he's messed around with it at all (well, I know he has: cam belt last year - but no mention made of any special treatment ;P).

Anyone who wants to have a poke around the engine bay to see if they can suss out where the extra 7 horsies have come from is more than welcome of course - will you be at the X-rally Mulley?

[saintjamesy89]

It's interesting to see Sandre's TZD made it's peak torque (which was more than mine and John's) 500 rpm earlier than John's and mine, could this be down tto the diufferent pumps fitted? John and I had the Lucas and Sandre the Bosch.

[Kitch]

Like Mulley's mentioned, there are different types of turbo too (KKK or Garrett IIRC?) so along with the differing types of pump this could have some answer to the issue. Only more testing of Bosch cars versus CAV cars taking into account the different turbos will provide the answers there.

In an ideal world we'd have a massive RR day with two of every type of BX there!

[Vanny]

In an ideal world we'd have a massive RR day with two of every type of BX there!

Well Noah, you best get building an ark for them all

[Kitch]

In an ideal world we'd have a massive RR day with two of every type of BX there!

Well Noah, you best get building an ark for them all

I think there is as much chance of it happening as Noah's Ark being a true story!

[Vanny]

Under much protest from the wife, i've spent the morning piecing this together. It won't win an award, and is pretty boring, but worth watching just once!

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