KNOWLEDGE IS HORSEPOWER

> PART ONE OF OUR LOOK AT WHAT DATALOGGING CAN DO FOR YOU

STORY MARKAR BLASTER PHOTOS PETER BATEMAN & SM ARCHIVES


> PART ONE OF OUR LOOK AT WHAT DATALOGGING CAN DO FOR YOU

TREET machiners are usually pretty quick on the uptake when it comes to taking something from the racing scene and applying it to their street cars. Whether itís running fat tyres on the back, bolting on a bonnet scoop or running spoilers and flares, what happens on a race track normally filters down to the street pretty quickly.

The uptake of data acquisition Ė or datalogging Ė has been a little slower. While people are quite happy to spend tens of thousands of dollars on an engine, wheels, paint and interior, when it comes to having something that will enable you to get the most out of your engine Ė and also prevent it from going bang Ė people donít always see the value.

In the past, installing a computer on a race engine meant a huge outlay on specialised sensors and equipment that resulted in reams of paper printouts filled with data to be analysed. These days, though, most performance aftermarket computers offer datalogging of up to 20 channels as a standard feature in the ECU (Engine Control Unit).

The Haltech Platinum Sport ECU that I use on my WAR440 Valiant was released approximately seven years ago, and aside from being superreliable and accurate, it was one of the first to offer datalogging as a standard feature, rather than a generally very expensive extra.

In most applications there are a number of channels you would want to log to keep tabs on the health of your motor, and many of these are even more critical on a boosted application, where reduced or increased input could potentially damage or destroy the engine.

Over the next two issues, weíll speak to a number of tuners and racers who would rather be without their left nut than go to the track without datalogging. First up, though, Iíll take you through what I have learned from using datalogging on my Valiant, WAR440. It runs a 500ci Wedge motor, with a ProCharger and water-to-air intercooler.

The Val was built with Drag Week-style events in mind, so last yearís inaugural Street Machine Drag Challenge was a great opportunity to put it to the test. In the months leading up to the event, the car had been running well, making big power and was very reliable. I felt it was a real contender to win the overall event, as at that time it was as quick as the leading cars, and it still had more left in the tank. Unfortunately not everything went to plan, but the Haltechís datalogging capabilities took the guesswork out of the post-event fix.

On the first opportunity to race at Drag Challenge, at a Street Outlawstype event in Albury, the car went lean in the burnout, signalled by a drop in power followed by a miss and backfire through the intake. It was later discovered that the fitting from the bottom of the intake manifold to the

MAP sensor had vibrated loose during the driving stage, so when the engine saw boost, it wasnít supplied with the right amount of fuel.

But everything else seemed fine, so we continued on until the car made a full pass at Calder and the engine dropped two cylinders. It seems it blew a head gasket between the two centre cylinders on the driverís side. After removing the plugs it was found that two of them were burnt. While we finished the event and the car still managed to run an 11-second pass with the blown gasket and in aspirated trim, the engine needed to come out so we could work out what had caused the issue.

After all, nobody wants to reload a new engine and then tear it up on the very next pass due to the same problem!

When we pulled the motor down we found that only a single layer of the Cometic gasket had been nicked between cylinders. It could have been weakened by it going lean in Albury, and was then pushed out when the engine saw boost. The best way to get to the bottom of things was to take a look at the datalogging results. Did we lose fuel pressure? Was the engine lean? Did we have an injector failure? These questions could all be answered by looking at the data stored in the Haltech system.

L O O K A N D L E A R N

WE BEGAN by looking at the burnout, which showed the engine hit 8400rpm at one point. But the engine has a 7800rpm rev limiter and at 7900rpm it cuts fuel and ignition, so how could that have happened?

If you look at the boost and throttle position, you can see that as the engine starts to come up on boost the throttle is reduced; it is actually the kinetic energy of the engineís rotating assembly that spins it up to 8400rpm, even though the throttle is closed.

CONCLUSION: The big over-rev canít really be fixed, as the car can just as easily unload the tyres at any point while racing. Substantially lowering the rev limiter could help, but that would give us a smaller window of revs to use. ou hrottle e 0rpm, ONCLUSION: , er dow e i y t t 8400 CO fixed p limite wind

B AT TE RY V O LTA G E

LOW battery voltage is a big issue in a hi-po engine.

Multiple fuel pumps, water pump, electric fan and the perfectly, ignition system all require 13.8-plus volts to run perfe ctly, perfectly, engine catch system, firing. change system. tensioner. voltage ignition system all require 13.8-plus volts to run perfe with the ideal voltage being 14.4. In this case the eng voltage dropped over the course of the power run; the half-dozen spikes are the alternator attempting to catc suggesting a blower belt slip issue.

In addition to the effect this has on the ignition syste which would really be struggling to recharge the coil between each discharge and thus lower the spark delivered to the engine, it also affects the injector firin Letís say that at 14.4V it takes 0.8 seconds for the injector to open; reducing the voltage to 11.6V can ch the injectorís opening time to 1.36 seconds. While this not sound bad, it clearly affects the engineís fuelling sy CONCLUSION: The low battery voltage was due to slip, requiring a different style of belt or a better tensio As a precaution, Adam from JEM also used the low-vo compensation table, which allowed him to counteract drop in voltage. He added low-voltage parameters to injector opening time to ensure that fuel supply was m ctly, gine e ch up, em, ng. hange s may ystem. o belt oner. oltage t the the met.

A I R TEMP S E N S O R

THE graph on the left clearly shows an issue with the air intake temperature sensor Ė it was out of range. This meant the sensor was either faulty or unplugged. Some tuners may allow the intake temperature to make changes to the engine tune, but in most cases these changes will be subtle, so that one faulty sensor wonít cause fuel or ignition modifications that can harm the engine.

Should a tuner want to allow a change based on a sensor reading, they can use the air temperature compensation table, where various percentages of compensation can be installed. In the graph on the right we see that with a 40į intake temperature Adam has allowed the addition of 0.6 per cent fuel.

With this system, if a sensor ever fails it will go to a lower number, so it will always it will go to a lower number, so it will always add fuel rather than lean out. Naturally, tuners have the option of turning this feature off so that whatever tune the engine runs on the dyno can be run exactly same way on the street or track.

CONCLUSION: The air intake sensor was clearly out of range; this could be easily fixed by replacing the faulty sensor with a new one.

C O O L A NT TEMP

THIS shows that the engineís coolant temp was fine on the track. But a great addition to the cooling system would be a pressure sensor, which detects boost leaking into the coolant system. It can shut the engine down if necessary, preventing a costly engine adding diagnostic IS e stem ost gine failure.

CONCLUSION: While there were no issues h the coolant temperature, it would be worth ding a pressure sensor to the engineís range of gnostic tools.

TH sys boo eng C with add diag


F U E L P R E S S U R E V S M A P

WITH any boosted application, a rising-rate fuel pressure increase in proportion to manifold pressure. When your manifold has, say, 10lb of pressure, thatís 10lb stopping the injector from pushing fuel out. This needs to be added to the fuel pressure to compensate.

Here we see that the engine showed good fuel pressure over the whole run. We could also check whether the pumps were doing their job: at 7000rpm we saw 62lb of fuel pressure at 20lb of boost.

CONCLUSION: This told us the fuel system was spot-on.

TH ssure regulator is a must. Fuel pressure needs to ease r pping e ere ssure ther ONCLUSION: t-WIT pres incre stop He pres whe s CO spot

O I L P R E S S U R E

WORKING on the assumption that 10lb of oil for period; pressure per 1000rpm is needed on a supercharged engine, it was clear that the oil pressure was solid fo this combo. It is interesting to note that the engine did drop from 68lb to 58lb over a 2.3-second period this may be because I was pedalling the car over the course of the run, but it was enough to make us take a second look.

CONCLUSION: This engine has 12 litres of oil in the sump, so while it does not have an oiling issue, the data showed there may be a need to doublecheck that the sump door was working properly and there was sufficient room between the bottom of the pick-up and the oil pan. d or d; e e e 132 STREET MACHINE

A I R- F U E L R ATI O / G A S T EMP

THIS engine is running dual air/fuel meters in the collectors. Before making any assumptions about the minor variances between the two meters, we took a look at the fuel trim table to check there were no fuel changes to either bank to compensate for manifold or inlet anomalies; in this case there wasnít.

Dyno testing with an EGT in each cylinder will give a true reading of how each cylinder is performing, but tuners have had to add up to 20 per cent fuel difference between the front and rear cylinder on some engines due to poor manifold design.

CONCLUSION: In this case there was no trim required.

The small difference between cylinders was more than likely due to air leaking around the slip-jointed collectors.

An easy way to check would be to swap the sensors between the collectors to see if they read the same. If they donít, it can then be attributed to sensor variation. f manifo g re th collec sensor same variat k ld , quired. han ctors. rs e. ion.

E N G I N E P R OTE CTI O N

ENGINE protection capability is probably the most exciting development in ECU technology in the past 20 years. If any of the criteria in the top table is detected by the ECU (low fuel pressure, low oil pressure etc) for more than 0.8 seconds, it will make changes to the engine as per the tunerís instructions in the bottom table. This means that, short of a mechanical breakage, there is no way you can further hurt your engine once the problem is detected. How the ECU handles the problem can be specifically tailored by the tuner.

So why did my engine hurt itself? Because Iíd turned this protection off while trying to get a handle on making tuning changes on the road. Díoh!

While my engine has most of the important items, the addition of eight exhaust-gas temperature probes (to monitor individual cylinder temperatures) and wheel sensors s GINE ing s. he ne e. e lem ng hile tion tor ors (to allow the ECU to run traction control) would things to the next level. More next issue! ENG excit years th m engin table p prob p tunin Wh addit moni sens take