This test was done on our 08 STI shop car. Before we get to far into the fun stuff, the STI is in our Stage 2 form. This means it has our twin cat downpipe, 3€ quad tip exhaust, and our Stage 2 AccessPORT tuning. With that said we are going to show 2 tests in this article one, the PERRIN 08 intake and the PERRIN Version 2 inlet hose.
First lets explain the dyno and testing methods we are using. In Oregon, we have 92 octane, using that fact, in stock form our put down numbers a little higher than 91 guys but a little lower than east cost guys. But still our 235WHP was pretty similar to what many people are seeing. Our dyno we are using is a Dynapack dyno. This isn€™t a dyno that reads high, or really low. In fact it seems to be pretty close to the mustang dyno in how it reads for most cars. All of our runs are done in 5th gear, and run for 14 seconds. Both of these factors play into the actual HP and TQ numbers we see. These factors are important to mention and important to understand as they can be manipulated to change the results. We could have made the dyno read a bit higher, by changing to 4th gear, or making the run shorter, but for tuning purposes, and future part comparos, this is what we decided on.
The new intake system is different than other silicone versions we used to make. We are moving more toward all aluminum intake systems in general on old and the new car. So this is the first all aluminum intake you will see from us. Using our newest MAF housing design, which incorporates a partial velocity stack into the front, we have a simple tube mating it to the OEM inlet hose. What is different about this intake as well as the future ones, is that its ONLY a cold air design. The filter is located down in the fender behind the fog lights and where a nice fresh bath of cold air is constantly passing by.
First up we did some runs and a little more tuning to our Stage 2 mapping. With that said we had our base line before we installed the intake system. Initial testing on our intake system showed the MAF curve was pretty close to the same as stock. Our first couple runs show that it leans out the AFR€™s almost 1 full point. For a tuned car this is not good, for a bone stock car it is good. With that said this intake will be one that requires a custom ECU tune. Our intakes in the past didn€™t have this issue, but this could be do to the change in the new MAF sensor, or the change to the intake housing. Either way we will be selling this as an ok part for a stock ECU tune, and a custom tune required for a car with an AP.
Our initial results with the car running leaner were very good. But it was on the verge of being a little dangerous for the off the shelf mapping. Also since the intake made the car run leaner, this doesn€™t prove that that intake being freer flowing makes more horsepower. This is important to note as we do not want to trick everyone into thinking our intake make more power than others. So in order to keep things all square and equal, we retuned the ECU to the same AFR as our stage 2 tune. This way the gains shown are gains from the intake flowing more air, not from MAF trickery. What is strange is that with out retuning the ECU we were seeing about the same power! Adding back in the fuel only caused a loss of about 3-5HP.
Even with all that said, 20WHP on stage 2 PERRIN map is huge! One other thing to note is the boost. Boost was the same before and after the install. Below, the green line represented the boost we were seeing. So what created that purple line??