MAPerformance
Senior Member
- Joined
- Nov 30, 2017
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- 103
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- 711
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- Location
- Cottage Grove, Minnesota
- Website
- www.maperformance.com
- Vehicle(s)
- 2017 SI Coupe
- Thread starter
- #1
To recap recent events: last week, we took our 2017 Honda Civic Si to the track for the first time (Read about day 1 here). Hot on the heels of the excited generated by that outing combined with the realization that we had ended the day very close to the current ET record, the call was made to dial in some changes to the car and get back out to the track this week. (9/12/2018)
We had previously determined that we were approaching the most easily attainable output we could see with the Borg Warner EFR6258 that was installed on the car. Having substantiated the raw data with track time, the decision was made to switch over to the larger compressor wheel provided by an EFR6758. The beauty of that swap is that the turbine wheel is the same, which required only the swap of the BW “SuperCore” with no other changes. We opted for the smaller .64AR housing because we had been struggling to get the “legs” back under the car after good launches, last week and hoped that the combination of the larger compressor wheel and smaller turbine housing would still provide the top end we needed while allowing us to keep as much torque out of the “hole.”
With the 6758 and the .64a/r housing installed the car went back on the rollers, previously we had seen a max of about 375whp peak, and in most cases about 350whp on the 6258 and .84a/r housing. With the 6758 now on the car and the boost at 38psi the car saw 402.24HP and 353.40tq (Dynojet Dyno, Smoothing: 0) (From what we can find, that is a new stock block horsepower record). We did notice some fueling artifacts and slight misfires up top, but nothing extremely unexpected considering the conditions: E50, stock fuel system, and 34psi of boost.
With a little room left on the table the call was made to stop there, and load the car up on the trailer for another adventure to Brainerd International Raceway. We packed our tools, and loaded up all our spares, but this time we bring a table to set it all on anticipating that we would potentially need some working space. It is the little details that can make or break a successful day.
5:30am 9/12/2018, up and ready to go for the day. We get to the shop, and since we had loaded up the car the night before, our day starts off a little easier than the last outing. Tools and spares are all loaded into the truck as we perform a last minute check, and then head out. The trip to Brainerd can take anywhere from 3-5 hours depending on your location in the metro, and the condition of traffic, so we opted to leave as early as possible to avoid slow downs. As we drive, the sun is starting to come up, but quickly behind that are some very dark clouds. “Not this again” we think. No quicker than the thought passing our mind, BOOM lightning strikes and rain follows. For the next thirty minutes it was a blinding downpour as we stare at the radar in hopes to see the storm pass.
We arrive and once again the skies open up and the sun starts shining. We set up our makeshift pit and ready our tools and spares for the day. The more organized we are now, the easier it is to fix issues and make changes as needed we will be during the day. At this point, we swapped from the street tires to the slicks, and perform a bolt and setup sanity check. We regroup near our work are and go over the goals: the objective for first half of the day will be to acclimate to the car now that it has nearly 50 more horsepower in the hopes that any changes we make will get us to our goal, namely achieve or exceed the record ET of 11.734 seconds.
Brian gets suited up and in the car as we are warming it up, tire pressures are set and he pulls up to the burnout box. The lights are ready and he sets up on the tree. The result: a causal 12.50 at 104mph clicks off on the board with a 1.8960ft. Looking over the logs, we see that the car actually loaded up a bit more and the boost was going a bit over target causing the car to break up after the half track. We turn the boost down a tad and do it all over again, this time we see a 12.63 at 109, 1.8860ft. That was a little slower than expected but the car seemed to like the run. Brian pulls back around to report that he had shifted the car a bit slower than normal but that it ran great. Back to the box! Brian pulls to the line and takes off, but as he goes to grab second the car wont shift and he is forced to abort the run.
We get the car back to the pits and begin to go over what could be causing the issue, visual inspection of the clutch, slave and pedal show that they are all in proper working function. We begin to pull the shifter cables and notice a bit of slop that we begin to think may be the issue. Some trackside changes are made and the car is set back down on the ground and ready for a test drive.
First gear is a bit notchy now, but two through six all seem to be operating perfectly so the decision is made to head back to the line! A big 2nd gear burnout is done, and Brian sets up on the tree. Two step set at 6500, and he is off. 1.8960ft once again, and a 12.16 at 114.56mph pops up on the board! Looks like we are back in the game! Back around and on the line, Brian clicks off a 1.8760ft, and a 12.19 achieving 114mph even. Now we are all feeling good as the car seems to be back and just hitting it’s stride. Lining up once again, two step is set, and as he gets the car to second we hear a noise!
Sadly it was not a good noise and the car quickly comes to a stop and is shut down. No fluids lost or parts dropped so we quickly push it back to the pits and get it in the air. Still no obvious signs of a broken parts, so its started again to inspect. All signs point to a damaged transmission, but without pulling it all there is no way to be sure what the failed part is, so the day called due to mechanical failure.
As we pack up and push the car on the trailer, we can do nothing but think about how the day went and try to sort through what may have gone wrong with the car. As the minutes pass, we all once again remember that this is how it goes when you push a new platform to its limits, you find the weak points. Although sometimes disappointing, it’s what is needed to progress and push forward in the name of development. We are now excited to get the car home and tear it apart to find what we failed. Without days like this, we would never learn or progress. Hopefully by next week we have the damage report ready and can share what we find and a plan to prevent it from happening again!
Thank you for reading, and feel free to post any questions you may have!
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