I repeat," If you are running 10psi with the stock engine and continue to do so, you need to find a proper tuner and get the ign mapping boost sensitive as well.." or I guess you can leave it how it is and blow the head gasket again and bugger the rings again. The cost of a Vampire unit will be more than an ign module.
Ok...Ok... I hear ya. I respect your experince and appreciate your advice. Like I said, if I add nothing else I will add ignition mapping. I just wish the Dynojet ignition module included a knock sensor. I love the safeguard of the closed loop feedback. Industrial instrumentation and controls is my trade. I pretty much live and breathe this kind of stuff all day, just on electric motors, valve actuators and analytical processes, not internal combustion engines. The Vampire would be double the cost of the Dynojet ignition module but I would probably go with it anyway if I don’t need boost sensitive mapping that’s also respective to rpm. So please allow me to ask my question one more time with a related example as I’m not really hearing a definitive answer.
My stage IV Yamaha Warrior has Wiseco 10.5:1 pistons AND a static or fixed timing advance of 2.5 degrees (not my build, I bought it this way). The timing advance provides some extra power on the top end but if it gets too much throttle under 3000 rpm in gears 3 through 5 it detonates to the point of audible pinging so I’m very careful not to do that. I considered removing the timing advance to eliminate the possibility of any detonation there but then I’d lose the benefit past 3000 rpm. I could install and program a Dynojet ignition module to pull the timing back to stock below 3000 rpm and have it advance from there as the rpm’s increased and everything would be good. Instead, in my quest for more low-end torque I bought a turbocharged Rocket… so let’s apply this thinking there as it seems to me we're looking at the same issue.
When the turbo goes to 10 psi boost at only 2500 rpm isn’t the likelihood of detonation greater there than 10 psi at 6500 rpm? Especially in a higher gear? Just like on my Warrior it seems that I would want to map in a retard of, for example, say 10 degrees at 10 psi at 2500 rpm but as the rpm’s increased reintroduce timing back in up to, for example, only 5 degrees retard at 6500 rpm as any more than that may not be needed there and just be robbing power. The boost stays at 10 psi from 2500 rpm to 6500 rpm but timing is adjusted as needed throughout the range and could even vary within the rpm range if needed (not linear). Isn’t this better, or even a necessity compared to just retarding, for example, 1 degree of timing per psi no matter where the engine is in the rpm band and what % of engine load it may be under? Since that’s the only thing the Vampire can do it would make the Dynojet my only option. Problem solved. If my thinking is incorrect here and I just need to make it “boost sensitive” regardless of where I am in the power band I can still opt for the Vampire and have the extra protection of a knock sensor. I can let my tuner work his magic on either.
Ok Now your right about the vampire unit having the ability to alter timing per pound of boost. This definitely might work since it is boost related not rpm related.
Works great for a supercharger as boost only increases as rpm increases but with a variable vane turbo the boost can be completely independent of rpm which I’m thinking would require rpm to be included in the ignition mapping, hence my question above.
Can I ask were you running premium fuel in her or a lower octane? Also have you been adjusting the spool up rate of the turbo (changing the shims)?
Premium fuel only! I at least know that much about detonation.
The newer Aerochargers have an adjustment for spool rate. Mine only has a spring for controlling at what pressure the vanes open and close. It’s currently a 9 psi spring which is what my max boost is probably closer to than 10 psi. It’s hard to tell on the cheap boost gauge I’ve got which is also getting replaced. This turbo is very touchy. If there's any engine load at all it will instantly "spool" or go to max psi with even a moderate throttle increase, doesn't need to be 100% throttle if I'm lower down in the rpm range.
In a previous discussion I told you I was not interested in a boost controller. I have changed my mind. My current plan is to install a 3 psi spring and add a manual boost controller that will be switched with a solenoid valve. I will be able to change my max boost instantly from 3 psi to whatever I adjust the knob on the manual controller to make. I’m thinking 10 psi but now since I’ll be adding ignition mapping maybe I’ll play around with it and see if I can do 12 psi safely.
I did actually do some testing with the spring and found that the turbo's natural minimum boost is 3 psi. Putting in a lower rating spring would not lower boost. It also can't help but make about 7 psi of boost at 6500 rpm. It's not possible to just limit it to 3 psi across the board, just at the lower end.
I suppose I could also get an electronic boost controller that would limit and ramp the boost up with rpm to mimic the characteristics of the TTS blower you’ve got. I’m really after that low end grunt though so I’ll battle how to best tune for that.