Last week I towed my Z to Florida so that Harry(Ztuner) could install Haltech and get it tuned. On my way down from Chicago I stopped by Z1 to pick up their PG axle back exhaust. While I was there I started talking with their Haltech tuner, Rob, and John(he was at the front desk though I can't remember what he said he did there). Rob told me I'd make more power using a H-pipe instead of the X-pipe I had on the car. Since I'm not building the car for max power potential it really wasn't a big deal to me. After I left(less than 5 min) I got a call from John that they would take some money off the H-pipe if I bought one. Of course I had to turn around. Once I got back and paid for the H-pipe, John asked if I wanted a shop tour. I don't know any car guy that would turn down a shop tour, so I of course accepted. Their shop area is actually much smaller than I thought it would be based on pictures I've seen of the entire building. The impressive thing to me was the amount of parts inventory they had, mainly for the Z32. I think close to 3/4 of their total inventory of parts, both new and used is for the Z32. They definitely have a very nice facility. I thne left Z1 with my new parts and continued my trip to Florida.
I dropped my car off with Harry that night, and came back to start tuning the following morning(Wednesday). We started the day with putting my car on the dyno and making some pulls with Nistune just to verify everything was working properly(I had a really bad stumble at 5k rpm over the summer). After several pulls we were happy that the car had no problems. We really didn't use the dynos wideband either. My car has a datalogger that is monitoring every sensor on the car and we ended up just using my widebands for tuning. The car put down 493whp and 454wtq, not bad but at that point we were ready to install the Haltech ecu.
This is what my logger looks like. It records the files to a SD card that can then be put into a computer to copy and show in the program. It turned out to be just as useful as the dyno itself.
The install of the Haltech ecu is as simple as remove your stock ecu and plug this in its place. We also installed the air intake temp sensor which fits perfectly into the short bolt on top of the plenum on the passenger side. Once that was all installed Harry changed a few things and the car fired right up. After several runs that night we noticed that fuel pressure was starting to fall off in the upper rpm. We decided we were going to install an Aeromotive fuel pump that Harry had at his house. We called it a night and would meet back in the morning to fix the pump. The next morning(Thursday) we did two low boost pulls just to verify we weren't going crazy the night before. After confirming that pressure was indeed falling we pulled the pump assembly out and installed the aeromotive unit. The install was fairly simple, the factory lower plastic piece(I have no idea what to call it) fit perfectly on the new pump so we were able to mount it in the stock location with the help of a hose clamp. We got it all back together and were finally ready to make another pull. The first pull with the new pump was done at base boost. A few pulls later we started turning the boost up but the power kept dropping. The car was only making ~380whp. We were stumped, nothing but the pump had been changed so we started to think that was causing the problem even though fuel pressure and air fuel ratios were perfect. We decided to swap the pumps since the car worked fine withe the stock pump. With the stock pump in the car we were still down on power, so we put the aeromotive back in. At that point we started thinking that either the car or the dyno were messed up. We pulled all the plugs for a compression test and got ~35psi on each cylinder. After we tested the first cylinder I thought I was going to die, but Harry said his tested was probably messed up. We went out and bought a new compression tester and now the compression went up to 160psi on all 6. Now we were sure it was the dyno, we pushed the car off and were going to spin the dyno "by hand" to listen for any bearing sounds. With the car off the dyno we couldn't budge it at all, that's when we discovered that the air compressor had some how been turned off. With no air supply the brakes on the dyno wouldn't release causing it to look like we were down on power. At this point we re-strapped the car down and did some more pulls. We got the pump gas tune pretty much set before deciding to call it a night. Earlier in the day Harry had commented that his car was low on gas and he'd need to fill up before going home. I had brought a 55 gallon drum with ~15 gallons of 93 and 110 gas mixed. It is an easy place to dump gas when switching between race and pump gas. I pumped out 5 gallons and dumped it into Harry's car. We went to leave and Harry called me letting me know his car died out. We started to drain out his gas tank, knowing that nothing else had changed on his car. Apparently a bunch of water had gotten into the drum somehow. We spent about an hour messing with his car before finally leaving. That turned into a very long day. Friday morning we got started right away and wired in the GM 4 bar map sensor and wired the widebands to the ecu. We then got the pump gas tune dialed in. 503whp and 477wtq
We swapped out the 93 for C16 and started getting that tune going. After two days of running into issues we finally had a day that went smooth. We got the car dialed in on C16 and ended up with 598whp and 560wtq, though at this point the temp inside Harry's shop had risen to 105*. We still had to swap the exhaust out to see what we'd gain from that. Naturally we had to take the car out on the street for some "testing". Those videos are on Ztuner's facebook page. We brought the car back and put it on the lift to let the exhaust cool so we could change it out. We pulled the SpecialtyZ x-pipe and mufflers off and put the Z1 h-pipe and pg on. We made 3 pulls to get a good average. That was around 7pm on Friday, I had a wedding to go to on Saturday so we called it a night and would try the x-pipe on Sunday when I came to pick the car up. Sunday afternoon I got back to Harry's shop and we swapped the h-pipe for the x-pipe, and got the car back on the dyno. We made 3 more pulls to get a good average, and then overlaid the results. Blue is the h-pipe and red is the x-pipe.
Even though they were on two different days the temps, humidity, and correction factor for all the comparison runs were the same. I'd say that they make the same amount of power. Our final numbers were 605whp and 582wtq at 26psi falling to 22 by redline. I plan on getting some stronger wastegate actuators to help with the falling boost which should get us some more power too.
I am very happy with the results, and I know that there is some more power to be made just by leaning it out a little, but using the car for road racing Harry and myself both wanted the tunes to be plenty safe. Once the weather gets nice by me we'll start playing with the launch control and possibly the flat foot shifting too. Lastly a link to the final dyno pull with the PG exhaust.
La-Z-Link
"Face it, you just can't beat stupid."
"Never underestimate the power of stupid people in large groups"
"My favorite glue is Hopes and Dreams. "
"My Z runs on gas and money." |
My recent tuning trip to Ztuner. - 
