Posted this in my build thread but didn’t want to leave the blog out! It’s LOOONG….you’ve been warned
Been awhile since I posted an update, mainly because I have not had much to report. But, I am happy to say the car is now tuned, running great, and short of a few more changes I plan to do this Spring/Summer, I think it’s done for awhile. I need to just sit back and enjoy it all now, as it’s been a tough road this past 1.5 years. Here’s why
The car was running great, made good, consistent power, and was a blast to drive. In my quest to be different, stand out from the relatively small crowd of built NA guys, and see what we could get out of the current engine package, I decided to embark on an individual throttle body project that I had high hopes for. There is a thread about it somewhere in here. I purposely kept quiet about it all since we really were in unchartered waters. I had never worked with this company before, had never used/installed an ITB setup before, and this was a new project from the ground up. Fast forward a few months and the prototype arrived in our hands. At that point, I had just dodged a major bullet with issues around the previous crank pulley that developed at ZDayz 2008 (that whole ordeal is found in this thread, I forget what page though) and since the car was finally back on the road in the heat of summer (July 2008), I decided to wait till the car was away for the winter to actually start the mock up/install. From December 2008 to Spring 2008 we spent removing my old setup, and test fitting the new ITB’s. By early Spring we thought we had an idea as to what changes needed to be done and prepared for the maiden tune. This was just going to be the test to see if things were on the right path, before we decided to put it into production. Unfortunately, it never panned out. The prototype unit simpl had numerous issues and we were never able to even do basic level dyno testing. We did our best to bandaid our way around them but it wasn’t to be. By summer 2009, I decided to cut my losses and bailed on the project. Now I needed to reconstruct things.
Fast foward to Summer 2009. A good customer and friend in CA with a well known VQ powered project/toy was interested in getting his hands on a factory polished Cosworth plenum, in order to retain a warranty on it. The Cosworth plenum we had previously shipped to him back when they first came out was a ‘first gen’ unit, which he had polished on his own. As such, there was no warranty on it, and he wanted to cover his bases in case it developed any leaks (he’s heavily boosted). We had the ‘second gen’ factory polished ones in stock, so a deal was struck. I got the first gen unit, and we sent him the second gen. By this time, I had already sold all the cool stuff/factory stuff I previously had on my car (carbon intake pipe, Gruppe-M carbon intake, our 3 inch MAF housing, my entire intake plenum setup). I thought with the ITB’s, I would no longer need them, and after investing tons of extra money/time into ancillary parts, I was just trying to recoup some. Not to mention, I thought had no need for these parts. Now I needed them more than ever What’s the addage about best laid plans?
In preparation for the ITB’s, I had also made the switch in December 2008 to the Haltech (since it could run solely off a MAP sensor, unlike my previous UTEC). I also acquired the Racepak dash in preparation to use it completely in place of the factory cluster (more on this later!). In doing so, we did some wiring changes to the Haltech that we felt would help with the packaging of the now defunct ITB setup, namely, using the throttle sensor on the pedal as the TPS. It was really more a cosmetic thing, as we wouldn’t have to worry about mounting/wiring a TPS sensor in the engine bay. I like things clean. We also had obviously converted the car to run a throttle cable instead of the drive by wire, and I had reflashed the ecu accordingly so it would not throw any codes our way. Due to these things, I decided I would contine with the throttle cable-based setup. I found a nice BBK throttle body from I think a Mustang Cobra that measured up almost perfectly to the Cosworth plenum. At 75mm, it was the biggest we could use without totally hacking up the Cosworth. The bolt holt spacing was also extremely close, and since it didn’t have an onboard TPS sensor, it would work out great and allow me to keep the TPS sensor on the pedal as I had done. By Fall 2009, I thought I was ready to tune, so brought my tuner back down to get things sorted. In addition to tuning, he was going to setup my Racepak dash for me, since I didn’t have any experience with such units up until that point. Unfortunately, it didn’t work out too well either. Numerous issues cropped up that day that prevented us from getting the car on the dyno. Once they were finally sorted out, it was simply too late in the day to do any dyno testing. So, we decided to just do a quick down and dirty road tune on the car. While the tune was far from ideal, the car was driveable, and I was able to use it for a few months until it was time to go away for the winter. It ran rich as hell, got crappy gas mileage and didn’t want to idle well….but it ran good enough to take the car out a few times on nice days, and at least well enough to move it in and out of the shop if we needed to.
During this past winter, we took the opportunity to do a bunch of things I had been putting off. Namely, finally finishing my C West hood project, the addition our new urethane transmission mount, making a new bracket for the throttle cable (thanks jiggy!), and other miscellaneous stuff. By this point I had also finally managed to integrate the Racepak cluster into the car completely in place of the factory unit. On the surface it sounds pretty straightforward, but it’s far from it. The factory CAN unit relies heavily on the factory cluster being there, and when it’s taken out of the loop all sorts of funky things happen. Since the car was down for the winter anyway, I also sent the cluster out to Racepak for a firmware update and for them to update the main plug on the back of the unit to the newer style one (which was said to give better screen resolution). I also acquired their USM (Universal Sensor Module) at the same time. This black box is essentially like a Defi control unit, but just for the Racepak. It allows you to add up to 4 auxiliary sensors to the mix and then control their display on the IQ3 cluster. I needed this in order to (hopefully) display fuel level, and also decided an oil temperature display would come in handy too, so I got one of their sensors as well. With the newly updated dash back in hand, I set out to try to integrate the factory fuel level sensor, as well as get it to display an odometer setting. I figured I’d leave oil temp alone for now, until the other 2 things worked. So far, it hasn’t happened. The odometer function is still not operable (clearly a software issue, which we hope to work out with Racepak shortly). The fuel level sensor is connected properly to the USM, but I cannot get it’s values to display properly. We’ve spent alot of time with it so far, and I am confident I’ll have some sort of solution in the near future. Meanwhile, over the winter, I had scheduled dyno time with my tuner to get a real tune done on the car. Rather than have him come down to use and use a local Dyno Dynamics like we tried the previous 2 times, this time I figured it might be best to make the drive up to him. I’ve known Mike from Innovative Tuning since 2001. He has one of our first Subaru customers back when we were doint lots of stuff with those cars. We developed a friendship, and he even designed/maintained our first website for us! Over the years, Mike got more and more hands on and eventually started and opened his own shop. Now he flies all over the place tuning people’s cars for them on various engine management platforms, and also does alot of work at their large shop in Buffalo, NY. I chose Mike because I knew he was proficient with the Haltech, is as straightforward a guy as you can get, and knows the mechanical as well as electrical side of things. The only thing is Buffalo is around an 7.5 hour drive from where I live! Last weekend we had some awesome weather, so decided to take the car outside finally, clean it up and do a quick shakedown run just to make sure everything was ok to take on the long trip. I got about 1/2 mile from the shop when snap…the damn throttle cable snapped! Really? Could you just kick me in the nuts one more time please, I don’t think I felt the last 1.5 years with this car enough. I limped it back homusing a folded business card between the throttle stop and the “rotary” that holds the throttle cable. Now it was Sunday night, I was supposed to drive 7.5 hours in just a few days, I had to tear things apart to get a new throttle cable. The first one I got didn’t work (totally the wrong design) but salvation was discovered at a high end bicycle store! On Thursday night I finally got the car set. All the while I had been going back and forth trying to get the damn fuel level to display on the cluster, but we just couldn’t get it worked properly. Obviously doing a long drive like this without a fuel gauge is less than ideal. Thank god for Apps!!! I found a simple one that tracked mileage travelled and used this to gauge when it was time for fueling stops. Like I said, less than ideal, but it worked out in the end. Crappy gas mileage aside, the car made it up there Friday night without a hiccup.
Saturday AM I got to Innovative, we managed to get the car in the shop and on the dyno with the help of about 25 2×4 boards stacked in various configurations (thanks guys!). Mike’s newest dyno is a Mustang. He previously had a Dyno Dynamics. Both are great units to tune on, since you get to apply load to the car and really put it through it’s paces at all sorts of rpm/load points. Way more convenient than street tuning for hours on end. Anyway, I know you’re all wanting to see the charts, and I will post them as soon as they are emailed to me this week. Basically the car made about the same peak power as it has previously though the new throttle body/intake/plenum did cure the small power loss up top that I previously had. Now the car hits peak power and it stays flat all the way to the 8400 rpm redline. Torque curve is spot on to what it was before, though has a higher peak now that we were able to dial in the intake cam timing a bit better (could not do that with the UTEC, but these cams didn’t need much tweaking here, just a few degrees). The car runs great, holds an idle really nicely at 1000 rpm (without any idle control motor!)
I did find some interesting things while the tune was being done. First, we tried dyno’ing the car without any intake at all – just letting it breath from the throttle body. I got a 10 whp increase and about 10 ft lbs of torque almost across the board. We then put the intake pipe back on, sans filter, and while some power was lost vs just running it open, most of it was still there. So, this HKS filter is costing me about 5-6 whp and about the same amount of torque. I think it may be time to do a real filter test and see what we can come up with. That will make for a nice summer project, and won’t stress me out like all the previous stuff has! On the drive home I noticed that intake temps were right around 67F (about 40 degrees outside) which I’m happy with, considering the sensor is mounted in the plenum itself and not on the intake pipe. Not too shabby , and shows me that the vented hood, and the intake ducting I did last Fall were time well spent. Perhaps I’ll experiment with a longer intake tube as well, or try to create a truly sealed cold air box and see if we can get those temps even closer to ambient since the warm weather is around the corner. Right now my main concern and project is getting this cluster fully 100% integrated into the car. I’ve also got this new rear to install (Quaife + 4.3 final drive!) that was another major project unto itself (I’ve gone through it in detail on our blog), as well as dropping the subframe to do the rear bushings throughout. That stuff will be coming up soon too, and I cannot wait to see how the engine responds to the new gears
That’s all for now. Thanks for reading!
Kwame
Z1 Performance
Jonathan
Corner Balance 