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.