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I thought I'd start a new thread to journal the progress of our shop car. Enjoy the ride as we move from stock to lightly modified to all-out turbo performance. We will build tunes and add them to our tuning database as we go, making it easy for others to replicate our results.
Our shop car is a 2004 RX-8 with just under 90,000 miles on the chassis. The engine is a Mazda reman engine with less than 10,000 miles on it.
On the dyno for the first time.
The dyno results - as purchased 100% stock and unmodified.
Last edited by Steve@VersaTune; 01-14-2019 at 09:00 AM.
Our first step is to establish a healthy stock baseline. In the first dyno, I noticed some jitter at high RPMs which lead me to believe that there was something not quite right with the ignition. So, we ordered a fresh set of stock coils and NGK plugs and wires.
The new ignition parts are in. Here are the old ones. Note the hot spots on the coils.
A new stock replacement air filter is on order as well. The mfg date on this one is 2012.
Last edited by Steve@VersaTune; 01-05-2019 at 10:35 PM.
These images are much better, but the dyno chart seems to be missing now? Can you post it again or at least let us know the numbers the stock car made?
The stock tune-up is done.
We installed new stock replacement plugs, wires, coils, and air filter. It felt smoother after the tune-up. I thought it was placebo effect until I saw the dyno. +9HP!
Here is the dyno:
Last edited by Steve@VersaTune; 01-17-2019 at 08:22 AM.
Reason: corrected dyno sheet showing tune-up plot vs baseline with positive gains.
Thanks. I'm trying to make this as repeatable as possible.
I wanted to create a healthy stock baseline to use for comparison. I have a rotary compression tester, but the lift was busy today. I'll do a compression test soon.
The VersaTuner performance tune for a 100% stock car is coming soon!
We ran a half a tank of fuel through the RX-8 on the dyno last night doing dozens of dyno pulls. We confirmed a lot of RX-8 tuning beliefs. Timing doesn't really do much on stock RX-8s. Leaner AFRs make some power, but you need to keep the health of the catalytic converter in mind and not get too crazy. Rotaries have high EGTs! More to come as we continue development of the RX-8 tunes.
I have a question, as well as a potential additional test you could perform.
Question: Are you using a premix on this motor? If so, what oil and to what ratio; and if not, why not?
Test: Does premixing your fuel affect horsepower/output. Its generally accepted that premixing has an affect on octane amongst other fuel characteristics, however the benefits of premixing are also well known and generally accepted as a beneficial habit. It would be interesting to have a comparison using healthy motor where any differences may have a more noticable difference (as a percentage decrease, or possibly percentage increase, who knows)
We have not tested with pre-mixing yet. We have not experienced any knock with stock or advanced timing. We can test pre-mixing to see if there is any difference.
Am also interested in the Pre-Mix concepts. Butt Dyno says yes, including a different exhaust note. Then factor in the F1 "Oil Leak" scandal...
One question, and no problem discussing off line, but do you have an idea of how close you % Load line is to your Calculated Max Load Line? Specifically around 6,000 RPM on a Stock Motor?
The max load I've seen is 1.07 at 5900 with ECT 73C and IAT 20C. The engine was still a little on the cool side. Typical peak load is around 1.035 with normal ECT and room temperature IATs.
I don't log percent of max calc load. It's an arbitrary value.
01-05-2019, 05:19 PM
