Hyundai Coupe Tuning - Engine
A popular performance modification is ECU remapping or chip replacement.
One is the ICON Race chip from Superchips. This module controls the ignition timing so that the spark will occur at top dead centre. This unit only controls timing and not fuel curves but will typically add around 7bhp although when I had it fitted to my coupe I gained 11bhp (this was after I had the pipercross fitted)
Other chips are available which will do timing and fuel. Both Unichip and Haltech are worth considering. A Super AFC can also be used to 'manually' tune the car.
There is a Powerchips in Australia that will do a re-map, but the car will be out of commission for a few weeks while its being re-programmed.
The Web Tuning Shop may also be worth a call.
For additional information, FXtreme have a pin-out diagram of the Hyundai Coupe ECU, note that this is only for US and Oz spec cars. See it here. Apparently you want to talk to Wayne...
(011) 61-3 9681-6888
106 Tope Street
S. Melbourne 3205 VIC Australia
Typical gain: 7%
Air Filter/Induction System
One of the most simple mods for the Hyundai Coupe is changing the way air is received into the
injections system. The simplist (and cheapest) way is the 'snorkus' mod which
involves removing the stock air box. Instructions for this can be found
Alternatively, induction kits are now available in the UK from K&N (K&N drop in filter #33-2573). At the time that I changed mine, they were not available, so I had a custom Pipercross induction system made .
Typical gain: 3-5bhp (7bhp in my case)
A good exhaust system will allow the exhaust gases to escape more quickly and
therefore help with engine efficiency. A free-flow exhaust system was used on
the limited edition Hyundai Coupe F2 Evolution. The exhaust was made by Magnex, but they no
longer manufacture it.
Cat replacement pipes can be done my most motorsport outlets, of course the removal of the catalytic converter will up the emissions - so watch out when its MOT time!
It has been found by other tuners that a little backpressure is required to help the gases to evacuate properly.
Exhausts systems are available from Pacesetter, KORE motorsports and Shark Racing do a universal system.
Typical gain: 5-7bhp
As the Hyundai Coupe has a dual overhead cam (DOHC) there is one cam for the fuel inlet
and one for the exhaust outlet. The current cams in the two litre Coupe have a
lift of .4 which is a semi-high profile. By increasing the lift the performance
also increases (fuel can enter quicker, exhaust gases can exit quicker as the
valves are open for longer).
It is reputed that the fuel inlet cam from the 1997 1.8 Lantra can be transplanted without any problems (this is the same cam as used in the F2 Evolution). This cam has a lift of .43, and hopefully your dealer shouldn't have a problem with this kind of mod as you are still using genuine Hyundai parts.
Cams will typical improve top-end performance.
Typical gain: 5-7bhp
Header (exhaust manifold)
A 4-2-1 exhaust header is available as a replacement for the Coupe header.
Although, generally better accelaration throughout the rev range would be
expected from this kind of mod, it may be at the expense of bottom-end
4-1 Headers are now being made, these concentrate on more top-end performance.
Alternatively the exhaust header from the Lantra works well. The Lantra header has a larger bore, thus allowing the exhaust gases to escape more easily.
Header work/port and polish
By 'polishing' all the internal components of the intake and exhaust system
(also known as gas flowing) you can allow gases to travel more efficiently.
The benefit of this is that air can be sucked into the engine and exhausted much quicker.
This can be quite a costly procedure as it takes a while to remove all the components.
Big Bore Throttle Body
Increasing the internal bore of the throttle body will allow more air into the
engine as well as increasing throttle response throughout the rev range.
The bhp increase of this mod is probably quite small.
An aftermarket underdrive pulley, such as those from
Unorthodox Racing, are made from a lighter material than the stock
pulley. Typically aluminium billet is used.
For each pound of weight lost from the crank shaft, approximately 2.7bhp is gained. Other gains are from the actual underdriving which accounts for about 15% of the totals gains.
Quotes from Unorthodox Racing:
"Unorthodox Racing pulleys can provide gains of 5 to 12 HP and 4 to 8 ft.-lbs. on normally aspirated engines and 8 to 16 HP and 8 to 18 ft.-lbs. on forced induction engines. These are average gains. "
"We do not push underdriving for two reasons. Our reason is to keep charging systems, air conditioning, power steering, and water pumps moving fast enough for every day driving. Second, not much horsepower is gained from extreme underdriving. All of our underdriving is done with the crank pulley, not the accessory pulleys. This is done so maximum weight loss can be achieved at the crank where most of the horsepower gains are found. "
Of course a combination of these mods can lead to an overall better increase in performance.
If you are thinking about getting maximum power from your engine it is
important to not forget about the things that you can't see.
The stock con rods and pistons are fine up to around 250bhp but after that you could be looking at some serious damage!
Con rods are available from Crower and high compression pistons from En.Dyn.