Engine B303 And E303...do They Need A Tune?

Noobz347 said:

Don't worry about it. 2000xp believes that digital tuning was summoned from the depths of hell or something.

I on the other hand, have seen some budget builds pick up as much as 80 HP with a good dyno tune. My setup picked up a bit more than that.

Here's the thing that's contrary to the "no tune needed" mantra. There's no A9L on the planet that is going to know what to do with injector pulse width, injector minimums, injector slope, or the duty cycle of ANY INJECTOR CAPABLE OF SUPPORTING 650 RWHP!!!!!

Now... having said that, there are some speed density setups out there that do very well with large injectors and some tweaking of manifold vacuum through and adjustable valve. I've seen that done as well.

You take 60 lb injector or even a 42lb injector and slap it onto an mass air computer and you'll be LUCKY if the damned thing even starts. A mass air meter calibrated for an A9L to function with 42+ injectors will still not be able to trim those injectors correctly for idle, part power, and WOT. I don't care how good the meter is.

The A9L was programmed specifically, to run 19 lb injectors and had the data necessary to properly trim (again) injector pulse width, injector minimums, injector slope, and duty cycle. All of those variables change when injector size is changed. The larger the injector, the larger the variation.

A mass air car making 650 RWHP on an A9L without a tune? I call BS unless it's a WOT only car. Any other power setting and that same car will be pig rich and run like crap. Untuned, that car will ALWAYS get waaaaaaaaaaaay too much fuel at any setting other than WOT. Finally, that mass air sensor would have to have been picked PERFECTLY for that car to even make a WOT throttle run with those injectors.

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Noobz347 said:

I've seen you post that link before and that's got NOTHING to do with whether or not that combo was tuned or what was used to tune it. I guarantee that more than just a mass air meter was installed.

Yes... 80HP between runs with digital tuning the only change. If you have issue with that, you need to seriously consider un-assing your couch, turn the speed channel off, and go down and watch the differences before and after dyno.

Dyno's have been around since before you were born. The first commercially available that I'm aware of was in the 1920's.


Air/Fuel ratios don't just magically fall into the sweet spot. A9L computers don't magically adapt to oversize injectors. Injector slopes between 19's and 42+ lb injectors are OUTSIDE of the EEC IVs ability to adapt. Someone with very SPECIFIC set of fuel based values, and flow-bench "might" be able create a meter that fluctuates enough to 'fool' the computer into thinking they're 19 lb injectors but that is most certainly the LONG and EXPENSIVE way around the issue. Particularly when there are SO MANY great mass air meters (some of them OEM) that have a standardized transfer function. Even then and "IF" that magic meter could be obtained, how many trips back and forth to the facility with the flow-bench for tweaking are the fuel tables are brought into tune???

Either way, that is still digital tuning. It doesn't matter which way you look at it. You either modify the transfer curve of the meter to make up for an unmodified EEC and injectors --or-- you modify the transfer function of the EEC to make up for an unmodified set of injectors and mass air meter. Most do both... A larger meter is run with a set transfer curve, larger injectors are installed, and a transfer function is inserted into the EEC so that AFR is correct at all power levels.

Short notes: Stop preaching about things that you don't understand. When you've digitally tuned a car (correctly, I might add) then you can come in and tell everyone how useless it is.

And just for the sake of argument... I've tuned with and without a dyno. I've tuned right on the street with a wideband AFR meter, a laptop, and/or an Anderson PMS. So the dyno statement that you made hasn't anything to do with anything.

Turn your own wrenches sometime instead of regurgitating garbage that you half-heard and thought made sense.

Click to expand...

Noobz347 said:

I've seen you post that link before and that's got NOTHING to do with whether or not that combo was tuned or what was used to tune it. I guarantee that more than just a mass air meter was installed.

Yes... 80HP between runs with digital tuning the only change. If you have issue with that, you need to seriously consider un-assing your couch, turn the speed channel off, and go down and watch the differences before and after dyno.

Dyno's have been around since before you were born. The first commercially available that I'm aware of was in the 1920's.


Air/Fuel ratios don't just magically fall into the sweet spot. A9L computers don't magically adapt to oversize injectors. Injector slopes between 19's and 42+ lb injectors are OUTSIDE of the EEC IVs ability to adapt. Someone with very SPECIFIC set of fuel based values, and flow-bench "might" be able create a meter that fluctuates enough to 'fool' the computer into thinking they're 19 lb injectors but that is most certainly the LONG and EXPENSIVE way around the issue. Particularly when there are SO MANY great mass air meters (some of them OEM) that have a standardized transfer function. Even then and "IF" that magic meter could be obtained, how many trips back and forth to the facility with the flow-bench for tweaking are the fuel tables are brought into tune???

Either way, that is still digital tuning. It doesn't matter which way you look at it. You either modify the transfer curve of the meter to make up for an unmodified EEC and injectors --or-- you modify the transfer function of the EEC to make up for an unmodified set of injectors and mass air meter. Most do both... A larger meter is run with a set transfer curve, larger injectors are installed, and a transfer function is inserted into the EEC so that AFR is correct at all power levels.

Short notes: Stop preaching about things that you don't understand. When you've digitally tuned a car (correctly, I might add) then you can come in and tell everyone how useless it is.

And just for the sake of argument... I've tuned with and without a dyno. I've tuned right on the street with a wideband AFR meter, a laptop, and/or an Anderson PMS. So the dyno statement that you made hasn't anything to do with anything.

Turn your own wrenches sometime instead of regurgitating garbage that you half-heard and thought made sense.

Click to expand...