[TitaniumTT]

Alright, well, I guess I better update this.

Finally had a clean dyno session. No fuel pressure problems at all. Started off by running on WG and fartin' around with the various valves and solenoids. For those of you not familiar with the Sequentials, here's a rundown of whats involved.

Turbo Control Valve - TCV located in the exhaust Mani - allows the full exhaust of the rear rotor into the 2ndary turbo
Charge Control Valve - CCV - Located after the 2ndaries compressor to keep the primary from backspooling the 2ndary
Charge Relief Valve - CRV - Vents the 2ndaries boost until it's ready to come online.
Pre-Spool Valve - PSV - works like a wastegate to send exhaust energy to the 2ndary to start spooling it up.

First thing I did was take my spare 2Bar MAP sensor and instal it after the 2ndary compressor and before the CCV so we could log what boost the 2ndary was producing. The only problem is that becuase of a slight pressure drop and us eventually running 14 lbs, I kept "overrunning" that MAP sensor and throwing an error, Oh well, just had to reset the errors between pulls. Started off with the transition occuring @3800 RPM's We made about 20 pulls on Tuesday and got the transition down to almost nothing - .15-.25s of nothing. On the street it feels interesting. Response is instant. The car just wants to take off! I was running ~55 on the highway, ~2700 rpms, blip the throttle to pass someone on the right and BAM! 15lbs of boost and the car just takes off. I'm making 250ft'/lbs by ~3200 rpms and I bet that would be lower. Dave was launching @ 3k on the dyno. In other words, the car goes from vac to 15lbs in ~200-400 RPM! From one log
Time = 5:07.448
TP = 40%
MAP = 90kpa
RPM = 2867
Time = 5:08.583
TP = 100%
MAP = 175kpa
RPM = 3226

So in the time of 1.13 seconds I gained over "12psi" (quoted becuase some of that is vac) in ~350 RPM's. Boost falls a little as the PSV opens to spin the 2ndary, the transistion is a blip and then hold on, torque just takes off.

Since the dyno I've moved the transition to 4000 and started messing around with the valves a little. In the discussions before we even started, Dave and I both came to the realization that the roller is going to slow everything down to the point where it would need to be dialed in on the street. It was great however to get the fuel map dialed in which was almost spot on. Even though we were venturing into areas of the map where we've never been before, our math and logic was almost spot on. A good feeling actually.

So we played with the CCV, opening it earlier or later proved to make the biggest difference in the reponse. We would either get a HUGE surge in torque, which just felt odd, or a slight dip during the transistion and then boost built again. This is what we opted for. After 21 runs (and 101 runs total) it seemed like we were chasing our tails and not getting anywhere, so we decided to call it for the night and head back after some street tuning.

What I discovered on the street was a little dissappointing at first. The dyno puts such a load on the engine that it would actually spool the primary faster. So while on the dyno we were seeing 11+lbs of boost, on the street, in the lower gears, I was seeing about half that. Easy fix, reduce the duty of the PSV becuase it works basically like a WG and viola, 12-15lbs on the primary.

I also incorporated something else that was pretty interesting, WG duty = TP vs RPM. So the more I open the throttle, the more the WG solenoid increases the boost. That made the single biggest difference in the way the car drives. She's MUCH less twitchy on me which is really nice. Much more driveable. She feels like a high-strung V8. No problems rolling through stop signs in high gears and 2k RPMs. Not at all like the previous rotaries that I have driven, this one is DRIVABLE

So the weather is not cooperating with me tonight or I would be out there tonight testing my new idea of surging the 2ndary a little more by PWM'ing the CRV to build more boost in the 2ndary and lessening the transition dip.

Something to try out tomorrow night if the weather, and Alex cooperate. We're heading North to go pick up his LS1.

So there it is, the car is done, and in 10 days or so she'll be stripped down and tossed on a rotisserie Just like I predicted in May.... Oh well.

FWIW though, I am glad I stuck with it despite what everyone said on the evil forum about the twins. They were all wrong, with the exceptions of a few who understood why two smaller turbo's > one large single.

I need to find some GT35R dyno sheets - what everyone told me to do, and compare them to mine and post them up. Show me one single that makes 250ft/lbs by 3200RPM's