A Major Breakthrough!

Posted on March 25, 2008 by admin

After missing out on racing at Snett, I thought I’d attack the performance problems, and first on the list was getting the thing re mapped on a rolling road.  When I’d fitted the CBR engine fourteen months or so ago I just down loaded from the Internet a high performance fuel map for my Power Commander USB3.   I wondered if the problems with performance were due to this being slightly out.  In particular I wanted to Iron out the power delivery issues that had been so evident when Testing at Snetterton.


So I dispatched the car off to Power-Tec In Peterborough for a mapping session, they had some staffing issues due to people being absent at trade shows… so I left the car with them for a week or so.

On the Friday I got a call and the result of the conversation was that they couldn’t map the car!
Why?.. Because it was running dangerously lean.  Their AFR sensor was showing a best ratio of around 17 but was mostly off the scale at 18+…. Bejesus! I’ve run it at Brands, Mallory and Snetterton like that  it’s a wonder I haven’t blown a piston. It is so lean in fact that they immediately stopped the rolling road session.  These CBR1000s are really bomb proof!

(Bing!… the big lightbulb goes on above my head) Running lean, also explains the lack of power, poor power deliver and the general overheating problems I’ve been experiencing since putting in the CBR1000RR. The root cause was low fuel pressure which I tested when I got the beast home.   The pump was delivering 2.5 BAR at idle, dropping to 2 bar under load.  The CBR specification is 50 PSI (3.5 BAR).  aargh!
I have a fuel pressure test guage and a wide band lambda sensor and If I’d had time to fit either of these diagnostic tools I would have seen the problem straight away.  But the focus on Diffs for the last 6 months or so meant that it had never entered my head.  Still hindsight is an exact science I suppose. At least we’ve found it now

The problem is that the in tank pump is for a zx12R, I had reasoned (erroneously) that this would output the same pressure as the dedicated CBR pump, plainly it does not.  Well I’m not about to change the tank and in tank pump… both are a right pain to get at and even bigger pain to seal correctly.  

The solution was to get a billet CBR pump mount CNC machined by Andy Bates at AB Performance (Series Sponsor for RGB). and then get this fabbed into a supplementary fuel tank along with a proper CBR1000rr pump.  That way the existing in tank pump acts as a low pressure lift pump to the tank and the CBR1000RR feeds the injectors at the right pressure.  I finished this in the final hours before going to Brands Testing.  I also fitted the Wide band Lambda sensor to see if it had any effect.

and so it was off to Brands Hatch for the first race of the season.


Posted in Fuel, fuel tank, lean | Leave a comment

First Race of the Season – Not

Posted on March 20, 2008 by admin

After the carnage of the chain jumping in testing I didn’t have much time to get the car ready for the first race of the season…. so some midnight oil was burned.


The other thing Dave Turner does is teach production engineering evening classes and I’ve been attending “Big Oily Toys Classes” for a while.  so when I examined the diff after the failure at Snett it was obvious that the problem is that the bearing carriers are just two thin in cross section.  this allowed them to twist out of alignment due to the poor shimming.. and carnage resulted.

So using new found skills learned in Evening class and my new Lathe, I made a couple of much more substantial bearing carriers out of some Ali billet… bolted the car together, shovelled out a couple of handfuls of  aluminium swarf, fitted a new sprocket and chain and off we went to Snett to race.

Except we didn’t!  Horizontal wind blown rain meant that the meeting was cancelled, and will be rescheduled until June… “Oh Dear” we all said in our best anglo saxon…. in fact many of us were whispering “Thankyou” when Viv Ayres the Clark of the Course made the call to cancel it and saved us from ourselves.

So I’ve still never raced at Snetterton arguably my home track.
Posted in Diff mounting, Snetterton | Leave a comment

Pre Season Testing At Snetterton and it’s broken again

Posted on February 28, 2008 by admin

So with the car together, well in advance of the season for once it looked like I was going to make the first race of the season.  I even had time for some pre season testing at Snetterton In Late February

I took along Dave Turner who is a pretty damn good chassis dynamicist (his blog is at http://dynamicist.blogspot.com/)  to help me setup the car.

Dave was determined to help me sort out my handling problems with the car… indeed I span at 20 MPH in the Russell Chicane on the day’s warm up lap :-( .  We ran a couple of damper cycles… This is basically a process where I go out and do a couple of laps with the dampers turned off… and then come in and tell him how the car felt… we’d add two clicks front or back and then go out again and report any changes.  After a couple of seasons my arse is now calibrated well enough to be able to correctly report what was happening in the car and Dave used his not inconsiderable expertise to interpret this into suspension changes.
Well when I say “We” I mean Duncan and Dave did the adjusting I just sat in the car and then went out and did two more laps…. Repeat process until car feels good… then when
 it starts to go off again  back off the last two clicks…..

I felt somewhat like a proper race driver, come in … report to engineer.. pit crew swarm on car… retest & adjust appropriately Its a great way to setup a car and worked like a charm… the thing is now just so chuckable.  Thanks Dave :-)  
The front rear balance is now as near perfect as I think I’m going to get without investing in some new dampers.

As a result I was now leaning quite heavily on the car… but still the absolute performance wasn’t there and power delivery was a bit crap.  it was juddering all over the place in the midrange and this was shaking the whole car and ruining the balance.  I was doing 1:29-1:31 which is 10-12 seconds off pole and last on the grid by a full 3 seconds.  By contrast a mate, in a car with notionally less power that he had never driven before went 5 seconds a lap quicker.  All pretty disheartening stuff really as I felt I was being brave enough and getting the lines and driving pretty well… Not Banzai  but it felt way better than 1:30s. 

The acceleration traces on my 
data logger looked “lazy”…especiallyy in the higher gears… so we wondered if the diff ratio was too tall for the new motor… se set about swapping the drive cogs around over lunch.
Unfortunately we think we got the adjusting shims mis aligned and three laps into the afternoon session this happened

Basically we think the rear sprocket was misaligned and the chain jumped and then started machining everything in touching distance.  This happened when I was flat just after the Richies apex … I thought I’d blown the engine judging by all the rattling
So I was then faced with rebuilding the drive train in two weeks flat to get ready for the first race of the Season at Snett.ARSE!

Posted in Diff, Snetterton, Testing | Leave a comment

So What’s been going on this winter?

Posted on February 11, 2008 by admin

After some gentle reminding, and indeed some firm poking with a sharp stick from various readers of this blog I thought I’d do an update and answer the question “What has been going on?”.  Indeed even Tim has been poked on his Blog to get me to update mine … perhaps some people do pay attention after all :-)

So here’s a fairly hefty update that will cover (at least in some degree) what has been going on for the last 8 months.
I seem to have spent most of the winter working at the back of the car.  Basically the new diff arrangement has taken a fair bit of time and energy to get right.  But it is finished now.
A rough sequence of activities is:
  1. I tried and tried to use the new starter motor that I had left over from the White Van as the motive power for the reverse system.  Unfortunately the motor span in the opposite direction to that required and didn’t have enough clearance around the main drive pinion to give me enough adjustment for when the diff moved as the chain tension was adjusted.
  2. I then spent a large amount of time drawing up and making  a split sprocket adapter… this worked fine until I weighed it.  nearly 5Kg of additional rotating mass was just too much to carry. So I dumped that idea.
  3. Duncan and I spent a long time staring at the arrangement and have now come up with a setup which is just as simple as it can get.   Two bearings a quaffe diff in between and a chain sprocket bolted to that. In fact this is quite an old photo as I now have some new lightened sprockets with lots of holes in them to further reduce the rotating mass.  The chain is tensioned by using aluminum shims between the uprights and the bearing carriers.
  4. Reverse is enacted by the winch motor being pulled up into the chain by a tension cable… this is pretty chattery and now is sporting a block of beech above the chain to stop the chin and winch sprocket from bouncing apart. I think I may need to make the actuation a bit more positive b some sort of Cam action in the future.
  5. The other major thing we did before the season was to tidy up the bodywork around the roll cage and throw some lovely metallic British Racing Green  paint at the beast.  At the moment only the side pods are done so the car is an interesting two tone red/green.  In fact its been likened to an old Ford Cortina with each wing a different colour.  But hey at least it is distinctive!

Posted in Diff, Diff mounting, paint, Reverse, winch | Leave a comment

Further work on the Diff.

Posted on November 8, 2007 by admin
While I’ve got the Diff unit out of the old cradle, and I’m while working on its mountings I thought I weigh it and see how much the thing weighs. So I dragged the bathroom scales down to the garage (Mrs M had already had a gentle chat about using the kitchen ones :-) ) and shoved the Diff and and reverse starter motor onto them. Total Weight a smidgen under 13Kg. Relative to both the old mounting frame and the blue diff that is a saving of 14Kg. Fourteen Kilos! Finding a single lump of fourteen KGs of weight saving in what should theoretically already be a stripped down race car is incredible and certainly more than off sets losing the convenience of an engine driven reverse.

The old electric driven reverse used to kill then engine due to the load on the starter motor when I engaged it. I wondered if this was because it was an old unit from a scrap yard. I’ve scrapped my former race support van due to the dreaded Tin worm , but one of the parts I saved was the brand new starter motor I had fitted to the engine. When I fitted this the old Cologne V6 span over  nicely and the new motor drew a lot less power. So I’ll try and use the new one for the reverse on the racer,better still it is another whole Kg lighter. It may mean that I’m going to have to make up some new bracketry but I was going to have to d that anyway.
Posted in Diff mounting | Leave a comment

Reverting back to old Diff

Posted on October 14, 2007 by admin

Well after four months of shaking off the disappointment of a season and development cycle wasted , I’ve decide that I do want to race again, and this year I’m going to be ready for the start of the season. So after finally deciding to abandon the other diff it is time to revert to my old one. I’ll lose the swanky engine driven reverse, but there’s no point in having a swanky reverse if you can’t go forwards is there?

Previously the old diff was mounted in a huge steel cradle and all told it weighed in at a massive 27 Kgs. I don’t really want to mount it in this way again so I’ve set about hard mounting it to some new chassis rails I’ve welded into the engine bay. This is the method that Tim Pell uses now and it seems to work OK, the Chain is tensioned by shimming the diff rearwards from the rails. So for the first time in months I’ve spent a couple of days in the garage and got some oil in my fingerprints. :-)

I managed to get chassis mods done and the original Diff refitted. This involved drilling and tapping the bearing mounting blocks to take some M10 bolts, and welding in two sturdy 1×2″ box section members to a couple of cross members in the engine bay. I’ll brace these new members longitudinally to the engine once. I finish fitting the reverse motor. As the drive chain is now being pulled pretty much centrally between the bearings it is unlikely to twist sideways like the blue one and as a result hopefully the Diff will not require any lateral support.
Now If I’m lucky, (and I could do with some) the original driveshafts will also fit. The chain is also shorter by 6 links and that too weighs a surprising amount.
Posted in Diff, Diff mounting | 1 Comment

Long Time no Post- so what happened?

Posted on October 14, 2007 by admin

After the Brands meeting I took the racer to the following meeting a Mallory park in early June. Here again I suffered major overheating problems. Mallory is a lovely short circuit, I qualified last, and in the race I managed to keep with the slower members of class C for a couple of laps but eventually I had to start short shifting again to control the engine temp and lost touch with them. So running glacially slowly and treating it like a bit of a test I also finished last and was lapped by everybody else in the field at least once. Not a good day.

So I took it home and set about building an oil cooler & air intake in the left side pod, using a take off plate provide by Colin D from the paddock. This took me a while and as we had four or five weeks before the next race I took my time and I’m pretty pleased with the result. This is a 40 row cooler, so it had better keep the damn thing cool.
So I was looking forward to the Double Header at Cadwell at the end of July and it seemed that finally I might have a chance of going a bit quicker once the thing was being kept properly cool, by the oil cooler.
This was not to be, When doing my pre race checks the week before Cadwell I discovered a full 10mm of play in the Diff output bearings on one side.
Obviously I couldn’t race like that and with 5 days to go before the meeting there was no possibility of getting it repaired either… So that’s another set of entry fees wasted.
After losing half the season to rebuild, engine swap and diff change, along with all the blood sweat , money and tears. Only to be much much slower than I was before… I’d had enough, and simply closed the garage doors and went inside to consider if I really wanted to carry on doing this racing lark as it was offering me precious little fun at the moment.
For those of you interested in the gory details this welded globule of steel is all that is left of the needle roller bearings that should be restraining the output shaft from the diff. Ohh I think that has got a bit hot!
So that was it for the season, Unfortunately I’ve been unable to get the diff repaired as the very nice chap who loaned it too me is simply swamped with work. I’ve basically had four months off and ignored all things race car related to try and rustle up some enthusiasm again or decide to give the whole thing up.
Still I have save a few quid in unspent entry fees.
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Brands Data Logging + Bypass Cooling

Posted on May 27, 2007 by admin
Tim and I use the same data loggers and analog inputs so that we can share our data for comparison purposes. Tim had put together some graphs for comparison between us. My Laptime is 59.xx his was 54. and some change. He’s in a class C car with some 40 less horsepower too so lets see where those 6 seconds went. (I’m blue he’s the black trace)

Click on the graphic to see a more detailed version.

The answer to where did those six seconds went is simply “everywhere” and at a uniform rate. The bottom trace “timeslip” shows my rate of time loss relative to Tim’s lap. It’s an even uniform line that shows I’m not bad in one particular spot but simply slower everywhere. The speed trace confirms this in that on average I’m 10-15mph slower than Tim everywhere except in Graham Hill Bend where I’m slightly faster. Interestingly I’m pretty much on the throttle everywhere before Tim is and I brake harder and later than he does. This i guess is a function of not being on the limit of grip like he is.

The top chart is corner radius which shows how tight we are turning and the traces are very similar so I’m not way out of position or driving the track in an odd way. I’m just a bit slower in ever corner and at every apex. The reason for this is shown in the G circle, this particular one is Druids and it shows that I’m not working the tyres at anything like the limit of their grip. Tim by contrast is nicely tracing the edge of the G circle as he transitions from straight line speed and converts longitudinal braking grip into lateral turning grip uniformly and evenly.

Basically if the tyres will give you 2G of grip you should be using it all for maximum braking and turning at all points through the corner. Although the Brake vs Turn proportion will change through the corner. Initally you start using all the grip for braking and will get full longitusinal brake G and then go to full Turn G and use all the grip for turning. I do each seperately Tim plainly transitions nicely between the two states using all the available grip at every point as his G curve traces a rough circle around the line that denotes the limit of grip.

It also shows that I’m largely back to my old habits of braking in a straight line before turning rather than turning and braking together into corners ( the Majority of the trace is moving along the Axis)

Of most concern is Tim’s ability to out accelerate me out of Clearways . He thinks my engine is underpowered. Personally I think I’m overweight. When I analyse the corresponding RPM traces the problem is clear. On average I’m 2000 RPM lower in the rev range than Tim is pretty much everywhere on the track. Therefore I’m always at least one and possibly two gears to high, this is killing the engine’s ability to rev and hence I’m accelerating slower.

So lots of things to work on here, Brake into corners, carry more apex speed, push the tyres and rev the nuts off the thing, change up later and change down further on the run in to corners to get the right exit gear. No more mechanical sympathy!

But with the thing cooking even when I’m effectively short shifting, revving the nuts of it is not an option until I resolve the over heating problems.

However I am in the process of fitting an oil cooler, plus I have an idea about the water cooling. I suspect that a fair proportion of the coolant is simply passing from the thermostat housing on the exit from the cylinder head and returning directly to the water pump on the side of the engine via the bypass hose (remember I’ve removed the thermost). The bypass is quite large bore and the pump will be applying a degree of suction to it as it connects on the input side of the pump. A good deal of the coolant is simply cycling through the the head, the pump and the bypass getting hotter all the time. At no stage is it going through the radiator and simply being re heated in the cylinder head with the corresponding problems controlling the temperature as only part of the coolant is actually being cooled by the radiator. So I’m going to clamp off the bypass hose for the next Meeting at Mallory and see what happens.

Posted in Data Logging, Overheating | Leave a comment