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Old 11-27-2010, 03:08 PM   #34 (permalink)
Joseph Davis
Join Date: May 2008
Location: ashEVILle, NC
Posts: 35

Beater Deluxe v2.0 - '89 Honda Civic DX
90 day: 44.68 mpg (US)
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Originally Posted by 99kleansi View Post
This is about the most sense I have head on this site. What injectors are you using? Injector dynamics are very good and are all balanced within 5% of each other in any given set.
Injector Dynamics 1000 and FIC 900 are Bosch injectors modified to 880cc. As stated before, I am using the black/blue tip Siemens Deka cores used on the 04-05 SRT-4.

Flow balance, as it has been marketed to you, is only important with aftermarket modified cores. Most of these cores flow a certain amount in a raw fashion, and are then restricted by one or more precisely manufactured tips that are crimped or seam welded in place. These aftermarket modified units are flow match at 3% duty in the 2000-4000 rpm range, and again at 85% duty, for the sole purpose of good idle characteristics.

A 5% discrepancy at idle in an OEM injector of the last decade would likely not pass emissions. Most of these modified pencil cores would be unacceptable to any OEM in the last decade.

Originally Posted by 99kleansi View Post
Are you tuning each individual cylinder according to EGTs or for overall advantage.
EGTs are for determining if there is a mechanical problem with the engine. The only time I'd do that are SBF in the 1400+ whp range as they have heat issues and are prone to thermal imbalance, despite which people still love them and insist on building them, so that's what you do. None of which has anything to do with a mild 200whp per liter street car, or for part throttle fuel efficiency.

Individual cylinder fuel and ignition trims, however, are vital for any performance tune. Those are best based off of the nature and condition of the carbon coat on top of the piston, and EGTs would not correctly reflect this. EGTs express the heat any one cylinder sheds, and not the heat that is absorbed and dealt with by any one cylinder. Much like octane, EGTs are not what people think.

All of this is entirely outside the realm of a FE tune, which would not require individual cylinder trims or temperature monitoring. Such things are largely a waste of time on a car like that. A highway cruise requires 12-18whp. Not to be hurtfully sarcastic, but oh no such power can hardly be contained?

Originally Posted by 99kleansi View Post
The ID injectors will make this real simple as the RC injector in the past were not as linear. The IDs also work real well at high pressure around 100PSI to def atomize the fuel.
You're talking about a huge power turbo car injector? 1000cc/min at 43.5 psi comes out as a stream and not a mist, at 100 psi and commeasurate increase in flow the bottom line atomization isn't significantly better. Not enough to make a FE related post in a FE forum about it, although the performance guys might like to hear that they have perks past smooth idle and big flow at big pressure.

For a 300-350 whp street car, I'll stick to the smaller pencil cores. Everything about them is better with regard to flow balance (irrelevant at the present technology level, unless you are an OEM appeasing the EPA/DOT) and especially FE.

Originally Posted by 99kleansi View Post
I am under the impression that no motor actually runs @ 14.7:1 as that would be unrealistic. I would assume you could get around 15:1 or 16:1 with almost no load on the engine.
Depending on the motor configuration, and injector atomization, 15.8-17.4:1 indicated AFRs is the tip over point where combustion pressures fall off. I ran an old D15B7 around at 16:1 part throttle and 13.9-14.2:1 WOT, you could feel the O2 sensor switch point at cruise as a slight surge. With the 12.5:1 D16Y5 I was in the 17's at a cruise and 13.0's WOT and it got much better efficiency due to quench/etc, despite the sportier gearing, with no closed loop surge, as well as better mpgs at all loads and speeds while making twice the power.

Originally Posted by 99kleansi View Post
In some programs on the Hondas you can allow the dwell angle in the distributor to accumulate more spark energy in the coil to help a more efficient burn with out having to fork out for an ignition system that would allow more sparks over a certain amount of degrees of rotation.
No, it doesn't work that way. I was the guy with the oscilloscope who tested that for eCtune, it was never correctly implemented. With 13.75-14.25 volts available you can only charge any given coil so much. Any particular design coil's inductive reactance, however, will require a different charge time at any given frequency (rpm) than another design coil will. That table is there to add a little bit more dwell to MSD Blaster2/SS coils in the 3000-6000 rpm range so that they function as well as a fresh OEM coil does - and due to the confusion I've passively advocated removing that table. There's no free lunch, at the end of the day performance cars need an ignition amplifier to get the job done. Conventional spark ignitions are very crude, and either the air/fuel mix lights or it doesn't. For low power FE setups, not worth thinking about.

Also, you want one spark, precisely timed, not multiple ones. That's another advertising campaign, thanks a bunch MSD.
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