Quote:
Originally Posted by Chris97
well actually i'm riding a base , what i'm looking for is a bit more torque and aggressiveness from the vtech..
i read that with obd2 tuning seems to be a problem , whats the best options for good tuning with the mods i'm doing ?
can i just stick the cams retainers and springs and see a significant gain without a tune or it be dumb to do so without tuning?
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1: To see whether or not you need to re tune your ecu for your cam modification , its best to look at what the professional engine builders like Mr. Jackson of Jackson Racing are doing and not the techs who just specialize in replacing defective parts.
The JR supercharger that he sells that is installed on the 5th gen Prelude ( 237 hp,201 ft/lbs) significantly changes the fuel demands of the engine over its entire power band yet the only modification to the fuel delivery system that Mr. Jackson required was a larger fuel pump. Apparently the stock ecu has the ability to adapt to engine modifications over a wide range .Just replacing a cam does not seem to be a reason enough to have to re tune an ecu. Given a situation where the proper amount of fuel can not be delivered, the Honda reputation protector #1 would kick in. It would detect a lean fuel condition and throw a code. Know some people have been able by tweaking the ecu fuel maps to improve the engine output power over the stock ecu tune but theirs a catch. These improvements are made using certain fixed temperature, barometric pressure , and some unique and probably linear type load placed on the engine. To understand what I mean by linear think of an exercise bike. Its has a mode of operation where simply as you pedal the load is gradually increased. It also has a real life mode where the load applied on the rider is constantly changed to mimetic a real would environment like when riding through the woods. Your stock ecu is set up to handle many different driving environments and engine loads so on averaged is usually superior to a dyno tuned ecu unless your your car was dyno tuned for some very specific application or set of conditions that you desired.
2: Honda Reputation Saver #2 : The Knock Sensor: :
Installing a cam that significantly increases the engine compression pressures can in some atmospheric conditions, trigger the engines knock sensor which will protect your engine by retarding the timing but at the same time can cancel out some of the gain you could have achieved by using the more aggressive cam. People who live at sea level and/or very warm climates may be most at risk for a knock sensor ,engine saving command to be sent to the ecu.Unfortunately I don't think a knock sensor signal sent to the ecu will trigger a fault code so many people don't have any way to know that their enhancements are being nullified at times by the device unless they rig up some way to monitor it.
Here is a little quote form an article that I was reading that indicates that Honda's engines were designed to work best with the better quality fuel that the Japs had and that here in the US, even with the stock cam on the H22a4 engine , the knock senors may have to be dialing back the engines hp at times.
"""All B18CRs are designed to run on RON-100 petrol which is a rather high octane requirement. To cater for lower octane petrols, Honda made use of the knock-sensor, a standard fitting to all Honda's DOHC-VTEC engine to retard the engine's ignition timing to avoid detonation. As a result, if owners of Integral Type-Rs runs with lower octane petrol, the power output will be less than Honda's spec'ed 200ps."""
note: RON-100 is like 95 or 96 octane using US measurement standards.
ref article:
Power of stock JDM Integra Type-R
3:Honda Reputation Saver #3 :The rev limiter and the fuel cut off
A good way to see if an engine needs any high rpm breathing enhancements like a cam is to look at how close the engines power peak is to its red line .My 2nd gen lude for example had the following specs:
Max hp : 110 @ 5500rpm
Red line: 6300 rpm
On my 2nd gen lude the engine red line was a 800 rpms away from its power peak rpm.
This engine ran out of breath long before the engine hit the rev limit.
I mean this engine was pretty much done as far as making power by 5900 rpm. This is an example of an engine that was in great need for a cam or other breathing type up grade and at the time JR sold upgrades like cams and headers for this car. The H22a4 engine on the 5th gen Prelude has a power peak of 7000 rpms and an extra 400 rpms to take advantage of what power potential is left after passing the engines peak power point. If you install cams that push the engine peak up closer to the engine rev limit, then you end up creating an engine with the ability to create power at some unusable rpms that are past the engines rev limit and/or fuel cut off rpm.This improved top end performance in some cases comes at the cost of the engines mid rpm performance at rpms that most people spend a lot more time driving.
Linear Mode
