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#103: 09-02-2015, 04:29 PM
Title: Vendor II
Location: playing in the snow
Car: 05 LGT, 96 Impreza L/WRX
Posts: 799
iTrader: (12)
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Alright, for our dyno day we did something a little different than what we did last time with the GR intake. I've compiled the results (as most of you know the server for our DD viewer is down, so these charts had to be made with raw data in Excel), and we're ready to share our dyno day with you!

The car we used was a forum member's (derp) and was equipped with an uppipe, downpipe, catback, and intercooler as far as performance modifications go. The car sees the occasional track day, and has 147k on the engine. Our tuner (Shane @ DB Performance) not only tunes race cars as well as road cars, but does racing himself. Keeping this motor intact was number one priority, so that means a good track tune, which is substantially more conservative than a street tune.

It was hotter than hell (for Minnesota) at 91 degrees F, and humidity in the dyno room at 54%. Derp and I stood outside in the sun all day while the tuner worked his magic. The dyno used is a Dyno Dynamics dynamometer, affectionately called "The Heart Breaker" and reads substantially lower than your standard DynoJet. So if the numbers sound low, its the conversion, not the vehicles. For example, our 2015 WRX put down about 180whp, where on a DynoJet it'll put down 220-230whp.

Derp's car has the aforementioned modifications and was road tuned by someone semi-local. Our tuner took a quick look at the tune (this was done via open source) and did our first dyno run of the day. This yielded a baseline of 207ftlbs and 177hp to the rollers. This is "Run 001."

I've decided to make one single dyno chart as opposed to multiple for comparison purposes, and will explain the runs as we go.

From here, the tuner identified some interesting fueling and boost control strategies from the previous tuner, and started to change to his own strategies. The first things he did were to change the MAF scale back to the stock MAF scale. This was important to us as far as testing goes so we could see if our "+12% over stock MAF scale" was going to work with this MAF sensor as well. It was also contributing to the very odd AFR curve of run 001.

The boost control strategy was also quite odd as well, with full spool at 4000rpm (15.5psi). This needed to be addressed too, so on to the Protune!

After a couple of runs he had boost control and fueling dialed in. Instead of a very very strange constant taper from 15:1 to 10:1 AFR, the car was running a flat AFR curve at 11:1. Full boost (16psi) was now coming on at 3700rpm instead of 4000rpm. After a couple more timing changes the tuner believed we had gotten all we were going to get out of the stock intake at 229.0ftlbs and 203.8hp. The DynoJet equivalent of these numbers would be closer to 280ftlbs/250hp, which is pretty impressive! Run 005 shows the final results of the protune on the stock airbox. Very impressive gains compared to what the car came in with, and shows that the tuner didnt hold back to "sweeten" the results.

Now, just like we did on the GR, we wanted to show what a simple hardware change did to the car at this tune level. Instead of protuning this intake too we chose to simply swap on the GrimmSpeed intake, do a dyno run, and then see what it would take as far as MAF scaling goes to match the stock airbox. We did this instead of performing further tuning to optimize the intake, as we already did that in the GR intake tests and are well aware of it's capability.

For run 006 I simply swapped on our intake, and Shane performed a pull with no tuning changes over the optimized stock airbox tune. As an engineer this was the exact data I was looking for, and the results did not disappoint. Immediately, because there is now less restriction in the intake tract the turbo is making about .75 more psi at peak boost. Not only that, but peak boost is occurring 200 rpm's sooner at 3500rpm. The car easily ripped off 240ftlbs at the peak (+20ftlbs) with gains of over 10ftlbs and 10hp everywhere. Our tuner cut the run off at 4500rpm as he doesn't like AFRs at 11.5:1, or the top end gains were looking to be even more.

This also showed the other chunk of data that was extremely exciting, look at the AFR curve between run 006 and 005. They are identical other than the .5 point difference. This shows exactly what we saw during GR testing: That the flow characteristics across the MAF behave exactly like they do on the stock airbox, just scaled. This means easy tuning, and predictable MAF readings.

The tuner knew that a difference of half a point AFR was equivalent to about 12% (the exact same as on the GR intake), and made the appropriate change to the MAF scale and completed run 007. Now, I've just realized that the legend for the boost and AFR for run 007 was cut off, but they are still on the chart. The colors of the lines for AFR and Boost is the same as HP and TQ, respectively.

The AFR for the GrimmSpeed intake with 12% scaled MAF (run 007) is spot on to the AFR for the stock airbox's run (005). No commentary necessary as it really does not get any better than that.

The difference in boost with the GrimmSpeed intake vs the stock airbox (007 vs 005) is direct physical evidence of the decrease in restriction that our intake provides. We see the exact same increase in boost and exact same earlier spool at run 006 (albeit a little cleaner), but if you look at the boost for the pink line (007) vs the boost for the purple line (005) you can see another thing we expect to see: As the RPMs increase the difference in restriction grows apart. The stock airbox is struggling to breathe in the top end compared to that with our intake. Whereas they are nearly the same boost value at around 4000rpm, by redline they have separated by nearly an entire psi.

Our tuner said we could easily make 220-230whp on this car with this setup. The intake coupled with our intercooler and quality 93 octane fuel could easily support these goals. However, the fact that the car sees track time, has nearly 150k miles on the stock block, a 5 speed, and not wanting to potentially pop derp's engine, the tuner decided to leave the car where it was. So we see untuned gains of about 5-10ftlbs everywhere and 5+hp everywhere, and evidence showing that much larger gains are to be had with protuning. Our results were impressive (and expected as the design is nearly identical to that of our GR WRX's intake) in that we were able to prove that our intake lowers restriction in front of the turbo, making it more efficient while being able to identically mimic the stock airbox's MAF readings.

So we achieved our goal, we're very happy, and you will be too as soon as we can get one into your hands!

The Following 10 Users Say Thank You to GrimmSpeed For This Useful Post:
Chris GTO TT (09-02-2015), Code (09-02-2015), covertrussian (09-08-2015), derp (09-02-2015), Grothe08LGT (09-02-2015), legacy360 (09-02-2015), lingling1337 (09-09-2015), MTBwrench (09-03-2015), PeterJMC (09-02-2015), rebourne (09-02-2015)