Category : Dyno Test & Tune
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CRV/BOV Testing
During my dyno time i spent about 15 runs testing the Bov. I tested the stock cap, all the springs, and our own BOV along with 1 run of no BOV. I spent a lot of time looking over the data and comparing my data channel i made called turbo rate of change. After all the testing there wasn't a very drastic change in rate from one BOV to the next. There was a difference in the stock spring and modded CRV cap compared to no bov, but it wasn't that much different. Here is a screen shot of what i would see. I took my PERRIN BOV and left it installed with the BW CRV. I had one vacuum hose setup that teed from one to the other. The PERRIN bov can be "turned off" by screwing the cap down all the way. That allowed me to test one the the other easily on the road. So what i found was compressor surge all of a sudden. I spent the next week messing around with things after work trying to figure out what was causing it.Problem Found.....
Then i had an opportunity to test out some new tuning methods for the stock ECU and i re-installed it. The stock ECU has all the normal Check Engine lights enabled and after i installed it i found that i had a CEL for a TGV housing (Bank2) fault. For those who don't know what they are the TGV housings are little butterfly valves that block off about 66% of the intake plenum to speed up air at cold start (and other times on the 08+ cars). My Cosworth ECU has no check engine light or fault detection for this so i had no idea! The one good thing,when it was plugged in, the Cosworth ECU defaults to them being open all the time so most likely the Bank 2 housing was opened for some period of time. The problem is when there is no power to the TGV, airflow can close it over time. Well funny thing is i left this unplugged when i cleaned my fuel injectors right after the EFR7064 was installed and just before i had to send it back. Why does this matter? This is a huge variable and for sure effected my dyno results for the worse. With only half my engine getting limited air flow during the dyno runs the results were pretty damn good. Below is a picture of the TGV housing and it being partially closed and one that is ported out.
Dyno Time
Needless to say, i didn't know about the TGV issue and i still dynoed the car and had good results. I had tons of really cool graphs all ready to show off, but most all of them are a waste as there is more HP on tap that i found. But below are a couple to give you an idea. I dynoed the car 1 week after some road tuning to test a few things out like boost control with the PERRIN Prototype push/pull wastegate. I did the same tuning as i did on the other turbos. 1.2, 1.5, 1.7 and 1.9bar of boost. I knew that this was a much smaller turbo, and less efficient at higher airflow, so i expected to remove some fuel. On the dyno i had to remove about 8% of the fuel to get my AFR back to where it was on the other runs with the other EFR's. The weird part was i was getting a litte knock like i hadn't had before. It wasn't bad, just something elevated compared to the last runs. Remember at this point i had no idea my Bank2 TGV housings were closed. First off the response is almost exactly like the OEM turbo. Check out this graph. What is amazing is the TQ and HP blow the stock turbo out of the water. Mostly because i was running more boost almost everywhere compared to stock. With the stock turbo this is not possible, but with the the EFR6758 and its larger capacity, it is! Now during all these runs i was seeing 140K turbo speed which is way way off the compressor map. This could partially be from the closed TGV housing, but more likely from pushing this tiny turbo too much.


