The life of Ryan's 2003 ZHP

[rkneeshaw]

Got out to take some video of the exhaust today. Take a listen and tell me what you think.

https://youtu.be/yVQ0lKMzif4

I think the Magnaflow sounds more raw and at WOT it is just amazing. But the Borla is more tame and sounds more refined.

[BMWCurves]

Nice, that's a lot of different comparison points! I think I like the Borla more. The Magnaflow I think lets you hear the headers much more at the lower end of the rev range, and I've never been a huge fan of that raspier sound in our cars, but it does sound nice at the top end.

[webster]

Love the sound of that Borla. I agree that the Magnaflow is louder and more raspy. I prefer the more civilized but still very aggressive sound of the Borla.

[slater]

thanks ryan, that was a lot of work to put that together. both sound great at WOT, but overall i like the borla better. more refined, less boomy. looks great too!

[Whammy]

Ryan, why did you switch exhausts? Wanted something quieter?

[rkneeshaw]

Ryan, why did you switch exhausts? Wanted something quieter?

Thats pretty much it. I loved the way the Magnaflow sounds at WOT, but for daily driving I wasn't at WOT a lot and I wanted something more tame. I decided to try out the Borla since the clips I've heard sounded good, and I had a theory the 2" dual pipes (compared to the 2.5" dual pipes the Magnaflow uses) would be a little less rowdy.

[rkneeshaw]

Dyno results!

Here's a comparison of the dyno I ran last time with the Magnaflow 16533 cat-back and now with the Borla 140084 cat-back. There were no other modifications done between these runs other than the cat-back exhaust swap. Its also worth noting the dyno for the magnaflow was done on a cooler day (60 degrees intake temp vs 80 degrees intake temp). I did some research and this math seems pretty sound:

Assuming the pressure stays the same...
Correction factor (Cf)
Temperute in Celsius(Tc)

Cf=1.18((Tc+273/298)^0.5)-0.18

So at 25 degrees C, the CF is 1 (STP or around room temp)
http://wahiduddin.net/calc/cf.htm

So its ~1.11% hp per 10degrees F temp change (no humidity or pressure changes)

That means from the start I should notice at least 7.3whp/6.6wtq difference just based on conditions.



So net difference is about 21whp and 2wtq, more than I expected. That Magnaflow truly flows that much better than the Borla. However, I'm ok with this. The Magnaflow with catless headers was louder while cruising on the interstate and I wanted to blow my brains out after driving for a few hours. The Borla is quieter on the highway and even after driving a few hours I can still get out of the car with a smile on my face. So it was worth the trade-off to me.

Also its worth noting, only because I"m not sure if it makes a difference, but the Borla cat-back I'm running had to be cut up and welded back together, and the welding work isn't pretty. The welder had to build up a lot of material on the pipes to fix a few cracks as well as fill some slight gaps. I wouldn't be surprised if there's some metal build-up or something on the inside of the pipes from the welding process that could be causing some turbulence. Whether a little bit of a brief restriction at two sections of the pipe would be enough to change things on the dyno or not is debatable.

I also took this opportunity to compare dyno runs in 4th or 5th gear. In my car 5th gear is 1:1 ratio which is what you want on the dyno, but you don't want to get the car over 160mph on the dyno so this means most dyno operators will run the cars in 4th gear. I was always curious how much lower the power readings are in 4th gear compared to 5th, and here's the answer:



These were back-to-back runs within minutes of each other. So that's about what I was expecting, maybe even on the high side. So FYI, if you want a big power pull try to get the dyno operator to dyno in 5th for you.

In other news AJ at ESS has been working with me to address a drivability issue I had in my old tune. its not finished yet but I'm really excited about the progress so far. I did a run with the new tune just for comparisons and its interesting how a pinch of timing and slightly leaner fuel mixture (without being dangerous) can make such a nice difference in output. I wont share the graph yet but I've got my power back from the exhaust swap so far, so at the end of the day I'm a happy camper.

[johnrando]

Interesting info.

Sent from my SM-G950U using Tapatalk

[rkneeshaw]

Ok so time for a big update! I've been having a lot of fun with the car, and a lot of frustration too. Lets get into it.

Not long after going to Gingerman back in May I felt I needed more support in my seat so I added a Schroth QuickFit Pro harness. This thing really works well (not quite as well as a full race seat and 5/6 point) for my dual purpose daily driver and occasional track car. It's 30 seconds to get them in and out of the car for race mode vs daily mode, and they make a real difference on track. Really holds you in place well so you can focus more on driving than holding on!



So with the new harness I was off to Gratton Raceway in Belding, MI back in September for a BMW CCA motor city chapter event that was a total blast and was very well organized. There was some great instruction and in-car instructors provided too. This was my first time at this track and it was so much fun. Its got some great elevation changes, some blind corners, off-camber turns, etc.

I had the GoPro but this was my first time using Harry's Laptimer and I thought it was triggering the gopro to record automatically. But I found out after I got home that the GoPro hadn't recorded at all So when I returned to Gratton at the beginning of October I made sure to manually start the GoPro and I got video from almost all my sessions. This time the event was organized by 3Balls racing and it was much more loosely coordinated, but I liked it, this time I was ready to face Gratton solo.

https://youtu.be/B-fTOt9qfXw

You'll notice the speedometer and RPM's jump around a lot. I'm using an OBDLink LX bluetooth OBDII device to feed that data to Harry's Laptimer (HLT) and what I'm finding is that the DME in our cars is not updating data over OBDII frequently enough to get good smooth data in the video overlays. I've added some tweaks to HLT that filters out all the OBDII PID's except for Speed and RPM and it helped quite a bit, but still isn't perfect. Oh well, its better than nothing I suppose.

Gratton has some real interesting turns and dips and even a section called "the jump". I'm running 10mm spacers on all four corners and stock suspension, and turns out a dip in turn 11-12 was enough to give me some rub up in the front, but it wasn't where I expected. The suspension was compressing so much that the tire sidewall was actually rubbing the plastic fender liner up inside the wheel well!



The car felt pretty good at Gratton but I think I'm advancing as a driver and I'm noticing more and more that the car is understeering quite a bit. I'm still using completely stock suspension other than PowerFlex bushings and stock staggered tires with 225's up front and 255's in the rear.

So I had to do something about the rubbing and the understeer and several folks recommended camber plates first over sway bars or a 255 square tire setup. The camber plates will allow me to get up to about -2.5 degrees of camber in the front, and not only will that help reduce the understeer but will allow the tire to clear the fender liner under heavy compression too. In went the Vorshlag camber plates





These things are really well built and they are super easy to change the camber between street and track mode. I can have the camber adjusted back and forth in literally about 2 minutes flat. And at first I was worried about them changing ride height but they are exactly the same height as the stock coil spring hats:



Meanwhile, I'm still trying to sort out this tuning issue that causes the car to buck and jerk when going on and off heavy throttle. Frustratingly AJ @ ESS has been trying to fix this for a while and decided he wanted to fix my cold starts instead. He felt I needed to upgrade my injectors but sent me injectors that wouldn't fit. In a rush to get the car back together for a track day, and after doing some calculations for the flow capabilities I need from my injectors given my current power output, I impulse bought some Bosch 42lb "green giants"



It turns out these are the injectors apparently that ESS includes in their Stage 3 Twin Screw kits. My calculations show that I was using probably 95% of the 30lb red bosch injectors I had so these 42lbers will give me a little more headroom to grow

After more than a year trying to get ESS to fix my tune issue I've moved on to another tuner and he had my fueling updated for the new injectors within a day or two ahead of the next track day, and has the fueling dialed in better than I've seen since installing the kit. There's so much more to share about the tuning drama I've been through but I'll save that for another time.

The other thing I learned while at Gratton is that my the O-ring on the cap of my power steering reservoir must finally have given up the ghost. I was getting some drops of power steering fluid splattering in my engine bay during the last track day at Gratton, so I ordered a new O-ring and now it stays nice and dry in there again. So FYI, those little rubber O-rings can and do get flat and need to be replaced in time.

So next event was a return to Gingerman Raceway in South Haven, MI. I feel like this is my home track because its where I first ever did an open track day. Its a fun track that offers some very technical turns. You can probably find 5-10 different racing lines around a few of these turns and there's always ways to improve. This time the car was ready with camber dialed in, although there wasn't time to get the throttle tuning issue fixed. So while the car was difficult to drive because of the throttle issue, it would have much less understeer and should wear the tires better



All was going pretty well until I blew through turn 10 during the second session out. The car just didn't seem to stop as well and I knew I wasn't going to make the turn so I took it straight into the grass. Got into the pits and took at closer look at my brakes and found I had practically no pad left!



Thankfully my buddy Jason happened to have a spare set of pads he brought with them. They were OEM formulation but that got me back on the track



I've since been driving on these Pagid OEM-style pads and they are really nice on the street. For a track day, they aren't too terrible as long as you're doing your heavy hard braking under 100-110mph. You get over that and you'll fade them and overheat them. But they do great on the street, so smooth and quiet.

I had the StopTech Street Performance pads for about 50k miles and what I noticed with them is that if you don't bed them regularly they will give you a vibration in the steering wheel while braking. After a good track day they were perfectly smooth, for a week or two of street driving before they started acting up again. Basically its an aggressive enough pad that it starts to clear its own bedding off the rotors during normal relatively cool daily street driving. So you have to constantly re-bed these for them to be pleasant on the street. And, they are better on the track than the Pagid OEM pads, but they aren't a LOT better.

I drove Jason's car at Gingerman with a set of Hawk performance pads and I was highly impressed, they can haul down some speed from over 100+ mph without breaking a sweat! Except they squeak like crazy on the street. So I'm convinced a dual-purpose pad like the StopTech's can be used for both daily street driving and track days but isn't really good at either, its just mediocre at both. So I'm of the mind now that its best to keep two sets of pads in this case (an OEM pad for street and a performance pad for track) and just swap them out between track events and daily driving. I like the super smooth quiet Pagid's for street, so now I'll find something better for track.

Thats probably it for 2017, the weather is turning cold and I've probably only got another couple weeks before the car goes back into hibernation for the winter. It's been a fun eventful summer for sure!

[704sw]

Great update. I wish there were more tracks near me (I don’t know of a single road course in NC), because I’m *almost* ready to HPDE this car.

Do you have the top hats marked between track/street positions, or have a camber gauge you use for the quick adjustments?