Last time with Project Elantra, we told you about a few of the gauges we installed in the car. We got some Auto Gauge gauges for seemingly no rational reason. The inanity continues henceforth, where we discuss more gauges that happened to tie in with our car upgrades.
When we installed the following gauges, we inadvertently timed them when the car had problems. We noticed a crack developing at our thin-wall stainless steel turbo manifold. We were told that more and more cracks will appear as the metal has already fatigued due to intense thermal expansion. Also, an errant mechanic dropped the car’s mechanical boost gauge to the ground, breaking it! Pity, it was an original Auto Meter…
And so on. Read on for these after the jump.
Exhaust Gas Temperature Gauge
This is the most expensive of the Auto Gauge collection we have acquired, costing almost twice that of the others. Perhaps the gauge’s thermocouple has something to do with the ludicrous cost premium. The gauge reads up to 1200 degrees Centigrade, a temperature which, FYI, is enough to melt uranium and the entirety of the Group 11 elements (copper, silver, gold). Another aside: around half that temperature is enough to melt aluminum. We’re seeing more than that in full throttle under load. Hmmm… we’ll get to that point in a bit.
An EGT gauge serves as an important gauge for engine tuning. To see its significance, we would have to begin with the events inside our gasoline engine. Everyone knows the basic Otto internal combustion cycle – Intake, Compression, Power, and Exhaust. The Power stroke is where the air-fuel mixture is ignited by the spark plug. The pressure generated by the rapidly burning mixture pushes down on the piston and con rod, is converted into rotary mechanical motion by the crankshaft, and in summation ends up moving the car. Power is maximized if the ratio of air and fuel in the mixture is at or within theoretical stoichiometric ratio (14.7 parts air to 1 part fuel).
Do you know that only approximately one-third of the energy generated by combustion ends up in moving your car for you? One-third of the power ends up being conducted at the cylinder walls and ends up in the car’s cooling system. The remaining third is expelled with the burnt gases at the exhaust stroke. This heat is substantive. Even on idle, Project Elantra emits an exhaust with a temperature of close to 400 degrees Celsius.
The funny thing about exhaust gas temperature (EGT) is that it moves in proportion with the air-fuel ratio (AFR). Meaning to say, EGT can act as a proxy to the AFR. The trouble is, the relationship is somewhat like a bell-shaped curve, the curve peaking at the theoretical optimum stoichiometry of 14.7:1.
If you think about it, this chart makes sense. The more perfect the combustion, the more heat you generate. (And consequently, more power. Heat equals power!) If there are imperfections in terms of either too much air or fuel, that detracts from the optimum, and the excess matter cools down the heat in the cylinder. And so, you will either see a direct or inverse proportion of EGT vs AFR, depending on which side of the AFR fence you are looking from. How then would you know which side are you at? With an AFR gauge.
If you were tuning a car, you would like to err on the rich side of the graph and work towards the top of the curve. The other side is not good, because a lean mixture may cause detonation. Detonation is an uncontrolled explosion event in the engine. Detonation destroys engine parts. Avoid. Additionally, peak optimal EGT changes based on several environmental and tuning parameters. The perfect EGT can change even on a basic cam timing adjustment. Best to use EGT as a guide and not as a target to shoot for if you’re not tuning using an engine dynamometer.
Note also that getting things too hot in the chamber is detrimental for engine longevity. Keep EGTs below a safe threshold. The Auto Gauge is set to warn us when temps are at 850 degrees Celsius. Should be a safe enough threshold.
Did we actually use the EGT gauge as a tuning tool? No. Tuning using the data of the EGT would entail repeated passes on a rolling road, monitoring the rise and fall of EGT to the car’s torque output, and also putting it in perspective to the AFR. Can’t really do this on a street/quick tune like Project Elantra is on right now. Speaking of a dyno, dyno time is expensive, and we have other more important things we could do with the money saved from a 3-run pass on the hamster wheel. So if you ask us, we wouldn’t know how much power the car is making right now. And when we do find out, rest assured that we won’t say it in this series of articles. (Feel free to ask us personally, though.)
(Note: the technical information in this section is sourced from this article.)
Turbo Manifold
Funny story: We bought the car’s original turbo manifold second-hand.
There was this one guy parting out a sweet and über-powerful turbo RD Coupe, and we bought his old turbo manifold. With runners made of stainless steel (the flanges were made of mild steel), the manifold looked good enough for us to use. But, after a couple of years of occasional use, it started to give up on life, as cracks started to appear on the outer, longer runners.
We asked the exhaust shop nearby, Jomar Exhaust Systems, to fabricate us an exact copy of the manifold, albeit in thick-gauge mild steel. It’s ain’t shiny, but in the absence of thicker gauge stainless steel elbows or steam piping, and in the interests of saving money, we’ll settle for this material. We could have asked Jomar to make us a trick equal-length “ramhorn” or “bundle of snakes” manifold, but we were prioritizing quicker spool times and the lack of further modifications to the other piping, et al. by just asking him to follow the old setup.
The manifold was painted in black high-temp spray paint, which easily came off with a solvent engine wash by our suki car wash, Futlus Auto Detailing. A permanent solution to stave off rust would be either to ceramic coat or chrome plate the manifold. When we have the time and the moolah, we’ll probably industrial-grade chrome the manifold to add some bling to the motor.
We also had the EGT gauge’s thermocouple installed at the same time. Some people mount the sensor as close to cylinder number 1’s exhaust port as possible. Others recommend it to be placed aft of the turbo. We located it at the collector, just before the turbo turbine inlet. Should you wish to install your own EGT gauge, please ask your tuner for his advice.
In the picture above this section, you would see a Turbonetics Deltagate external wastegate mounted at the manifold. Thanks to our friends at Haltech Philippines for giving us a good deal on this item. Not that we’re now using such a thing for boost control, that allowed us to have a separate exhaust pipe for the excess exhaust gas, improving boost response. We just had Jomar point the sucker up towards the stratosphere, killing what’s left of the ozone layer.
The problem we have with the manifold is that it is difficult to properly secure the turbo to it. While racing the car, the fasteners easily come loose and thus run the risk of the turbo liberating itself from the engine! (Well, the wastegate tried to do the same in Batangas.) We may be revising the manifold in the future to have more vertical space between the flanges and the exhaust runners, enabling us to double the fastening nuts, thus hopefully eliminating this bugaboo.
Boost Gauge
The purpose of the boost gauge is to read the positive pressure generated by the turbocharger. Sans turbo, the engine would only suck in atmospheric air pressure, which is 1Bar, 14.7 psi, 100kPa, whathaveyou. (We’ll use Bar as our unit of measure in this discussion. Our boost gauge actually reads in psi, our preference.) When the boost gauge says that the turbo is pumping out, say 0.5 Bar, the engine is actually breathing in 1.5Bar of air.
As mentioned ealier, a faux pas resulted in a broken boost gauge. We’re still grieving for its loss. But our new Auto Gauge does something that our old Auto Meter gauge didn’t. It also reads vacuum, which is basically the inverse of boost, measured in either negative Bar or inches or millimeters of mercury (in.Hg/mm.Hg). Since our new boost gauge reads in imperial, vacuum is read in in.Hg.
The final difference between the Auto Meter and the new one is that the former is a mechanical gauge and the latter electrical. The needle in the old gauge moves in direct response to actual boost pressure plumbed to the gauge unit from the charge piping. The Auto Gauge has a sender that reads boost/vacuum and relays the information to the gauge via electric signals. One of the advantages of the new gauge, and other electrical gauges for that matter, is that it is easier to lay and route electric wires to the cabin than the signal lines for air pressure, fluids, etc., needed for mechanical gauges. However, with mechanical gauges, you don’t need electricity to read vital information. Again, read this article for the pros and cons for each gauge type.
Fuel Pressure Gauge
We never meant to buy a fuel pressure gauge. It came with the copy adjustable fuel pressure regulator that we bought as per the instructions of our super modified engine tuner Art Rodriguez of Haltech Philippines. Iikdo Car Accessories supplied us the copy unit and a compatible adapter to our stock fuel rail. We cannot comment on reliability yet – it’s holding up to the regulated 3Bar (45psi) of fuel pressure so far, so here’s crossing our fingers.
The oil-filled mechanical gauge is mounted directly at the regulator. It helps as a diagnostic tool to rule out fuel pressure problems, but does not add to the ludicrous light show of gauges in the cockpit, thus minimizing contribution to curb cred. If we had cash that we would otherwise use as compost, we might get another Auto Meter gauge to measure fuel press. Or not.
Future Plans for Instrumentation
One gauge we would like to have is a voltmeter. Our reduced-size battery has the tendency to easily run out of juice, so an ability to monitor battery power will allow us to know when to beg for a jump or not. Another gauge that we’d like to see is one for showing air/fuel ratio. We already have a Haltech-branded wideband sensor and controller bunged and wired in, but we did not spring for the optional gauge.
To be frank, the ultimate instrumentation solution is already inbuilt in almost all modern vehicles. The car’s stock ECU already has the majority of relevant sensors keeping track of the goings-on of the engine. Using the information, the ECU adjusts ignition and spark to suit the ambient conditions. The thing left to do is to access the data which, without a capable diagnostic gadget and a proper display, would be impossible.
We’ve deep-sixed the stock ECU in Project Elantra and had a Haltech Platinum Sport 500 wired in its stead. Now we can just plug in a laptop and have information overload at our convenience. We can even use the laptop as a “black box” and record our driver’s actions on the fly. But to use a laptop for this purpose is cumbersome.
The Goldilocks solution is to get the Haltech IQ3 logger dash, seen above. Nothing says “mo-f**k’n race car” than this puppy in your instrument panel. And it will accept readings from the ECU and a hell more if you can think of some other necessary inputs. Too bad it costs a ton. When we win the lotto, this will be near the top of the post-win shopping list.
Next time on Project Elantra, expect something about engine management. Stay tuned, and keep it slow out there.