What To Adjust When Dyno Tuning? How To Get All The Horsepower Out Of Your Honda Acura Engine

Once the car is warmed and the power output has stabilized, you can start making various adjustments. There are a couple of adjustments that can improve the power output of your performance Honda Acura.

Ignition Timing - The engine control unit (ECU) in your car is programmed to control the ignition timing. The ECU settings are on the safe side and that is because most people drive on low octane fuel. Low octane gasoline can cause detonation that can and will destroy the pistons. If you really want to have a performance Honda Acura car, and you are willing to pay a couple of extra bucks for 92 octane or better, then you can play around with the ignition timing to extract a bit more power. Once the car is on the dyno try advancing the timing 2 degrees at a time and observe the power increase or decrease. On most Honda Acura cars if you increase the timing more than 4-5 degrees above the factory specifications you should be very careful. After 4-5 degrees of ignition advancing you can get detonation that can damage your engine. If you hear the talltale ping or metallic ring sound back of the gas at once. Do not tolerate detonation for more than a second or two. If you are going to drive on low octane gasoline have your ignition timing set at factory specifications. Repair manual is helpful for instructions on haw to adjust the ignition timing. You will also need a timing light to eliminate the guessing. Don't just guess and twist, do it right or you can get detonation. Do not assume that if some advancing is good, more is better. Advance the timing in two degrees steps until the power either flattens or decreases then back up slightly from there. Later when road testing, if you notice any detonation you may have to reduce the timing even further. road conditions load the car a little different than dyno. Expect from 2-5 more hp by adjusting the ignition timing and better fuel.

Camshaft Timing - Honda and Acura like most other cars, have there cam timing set from the factory for minimum emission and maximum power as secondary goal. Most production camshafts are designed with a minimum overlap and a wide spread lobe separation angle to reduce emissions and ensure smooth and stable idle. Since emission and idle are not so important for performance Honda Acura cars, more power can be extracted from the engine with a little cam timing adjustments. DOHC engines respond very well to better cam timing. V-Tech equipped Honda Acura cars and even the D- series SOHC engines can almost always benefit from some cam timing tuning. To be ale to change the cam timing, adjustable cam gears are going to be needed. A repair manual is very helpful when replacing the stock cam gears with adjustable ones. Don't try saving a few bucks by buying cheap adjustable cam gears. The cheap gears are not manufactured well and they can slip. This can cause anything from power lost to total valve train damage if a piston hits the valves.

When on the dyno on DOHC B and H series motors start by advancing the intake cam by 2 degrees at a time. Test in between until the power falls down or you are happy with the power output. If the power falls right a way, try retarding the intake cam. After adjusting the intake cam try retarding the exhaust one. Do one or two degrees at a time until the power drops. If you are not getting any respond try advancing the exhaust cam. Many engines seem to like the intake 4-5 degrees advanced and the exhaust 1-2 degrees retarded. Here are the combinations that you can try when adjusting cam timing:

• Advance both intake and exhaust cam -  Increases bottom end power while decreasing top end power. The exhaust vales are closing earlier and intake valves are opening sooner.

• Retard both intake and exhaust cam - Increases top end power while decreasing bottom end.

• Advance intake only - Increase bottom end and mid range power without loosing to much top end power usually. Works good on stock heads or heads that flow poorly. This is good to try on dyno with street car and mild cams.

• Retard intake only - Helps top end power at the expense of lower mid range on big duration cams for race cars with good head flow. Stock type street motors do not like this usually.

• Advance exhaust cam only - Not so good because the exhaust valve opens sooner and shortens the power stroke. Usually helps top end power on big duration race cams with good head port. Stock type street cars do not like this.

• Retard exhaust cam only - Increase overlap and helps bottom midrange power. Works best on stock heads or heads that flow poorly. Good thing to try when adjusting cam timing on dyno. Most Honda Acura cars like just 1 or 2 degrees of exhaust cam retarding.

On SOHC engines you can either advance or retard the cam shaft. Advancing it will increase bottom end power while decreasing top end. Retarding the cam will increase top end while decreasing bottom end.

While dyno tuning you do not have to try every possible option. If you are getting a good results with some combination continue in that direction. For example, if advancing the intake cam moves the powerband to where you want it, you do not have to try retarding the cam also.

When adjusting cam timing on the dyno, it is better to go a little bit under the power curve rather than maximum peak power. Having 4 more horsepower form 5500 to 7800 rpm will get you down the track faster than having 7 more from 7500 to 8000 rpm. You should adjust the cam timing to get the most power in the rpm range where the Honda Acura will be pulling the longest in each gear.

The piston to valve clearances decreases when advancing the intake cam or the intake lobes in the case of SOHC engine. In most cases you can advance the cam at least 6 degrees before you need to worry about contact. If you are not sure measure the clearance before you advance the cam more than 6 degrees. The same does not apply for engines with heavily milled heads and long duration cam shafts.

It is possible to see gains of up to and over 10 hp, but usually 3-5 hp across the rpm range is more typical. It is important to remember that any changes to the intake and exhaust system can change the cam timing that the engine likes. After the cam timing has been set the engine may like a slightly different ignition timing. It is a good idea to go back and play a little with the ignition timing.

For turbo charged Honda Acura engines reducing the overlap by first advancing the exhaust cam and retarding the intake may help, especially with smaller high backpressure turbo chargers. It is the same for supercharged motors with bigger than stock cams. Large race type turbo chargers may respond to cam tuning pretty close to what naturally aspirated motors may like. 

Fuel Pressure - To make changes to the fuel pressure you are going to need an adjustable fuel pressure regulator. After adjusting the cam and ignition timing try a little tuning to the fuel pressure. The Honda Acura engine may like a little different fuel pressure after changing the cam timing. Start by increasing or decreasing the fuel pressure by 2% until the power flattens out.

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