SwedishKnievel
New member
- Joined
- Sep 16, 2013
- Location
- Los Angeles
The essence of the problem is that I'm unable to control boost.
The motor is a 94 b230ft. It's been converted to microsquirt. It has LS2 truck coils, Red fuel injectors, 3 in custom downpipe, Open 3in Exhaust, oversize Pistons, new valve job, Red fuel injectors, walbro in tank pump.
My ambition was to raise boost to approximately 12 PSI. My first attempt included an electronic boost controller. I never was able to get that to work and boost levels remained at factory settings. Roughly 7.5 PSI. I then introduced a manual boost controller. Immediately it became clear that the Boost was increasing unchecked. I double-checked the plumbing for the manual boost controller and determined that it was plumbed properly but even with the manual boost controller essentially open presenting no restriction or resistance to the Boost signal the wastegate was not effective in limiting the amount of boost. I suspected a bad wastegate but it seems to test okay on the bench. I replaced it anyway with an aftermarket type from Kinugawa. I started with a 0.8 bar Spring yet still the Boost climbed 2 in excess of 14 PSI 4500 RPM. I switched out the spring to a 0.6 bar and while boost was equally uncontrollable the Boost curve did change in that at any given RPM the Boost was lower with the 0.6 spring than it was with the 0.8 spring although with both Springs the Boost was headed to catastrophic levels.
At this point I suspected some mechanical issue so why tested the wastegate with a hand pump while fitted to the turbocharger on the motor in the car. The external actuation observed seemed appropriate. I've then suspected that perhaps there was some mechanical problem with the wastegate itself inside the turbo housing. But after removing the downpipe and again observing the wastegate Actuator, it seems to be consistent with normal operation.
The wastegate actuator is connected to the turbo housing nipple with a short piece of new silicone hose. I've checked to be sure that the turbo housing Port is not clogged or blocked in any way.
If anyone has any ideas as to what's going on here, I would sincerely appreciate hearing them. I'm really at a loss for what's happening. Complicating matters is that this is a track only car without registration so my only opportunity to identify these issues is at the dyno and that is a bit of a hassle never mind the expense.
The motor is a 94 b230ft. It's been converted to microsquirt. It has LS2 truck coils, Red fuel injectors, 3 in custom downpipe, Open 3in Exhaust, oversize Pistons, new valve job, Red fuel injectors, walbro in tank pump.
My ambition was to raise boost to approximately 12 PSI. My first attempt included an electronic boost controller. I never was able to get that to work and boost levels remained at factory settings. Roughly 7.5 PSI. I then introduced a manual boost controller. Immediately it became clear that the Boost was increasing unchecked. I double-checked the plumbing for the manual boost controller and determined that it was plumbed properly but even with the manual boost controller essentially open presenting no restriction or resistance to the Boost signal the wastegate was not effective in limiting the amount of boost. I suspected a bad wastegate but it seems to test okay on the bench. I replaced it anyway with an aftermarket type from Kinugawa. I started with a 0.8 bar Spring yet still the Boost climbed 2 in excess of 14 PSI 4500 RPM. I switched out the spring to a 0.6 bar and while boost was equally uncontrollable the Boost curve did change in that at any given RPM the Boost was lower with the 0.6 spring than it was with the 0.8 spring although with both Springs the Boost was headed to catastrophic levels.
At this point I suspected some mechanical issue so why tested the wastegate with a hand pump while fitted to the turbocharger on the motor in the car. The external actuation observed seemed appropriate. I've then suspected that perhaps there was some mechanical problem with the wastegate itself inside the turbo housing. But after removing the downpipe and again observing the wastegate Actuator, it seems to be consistent with normal operation.
The wastegate actuator is connected to the turbo housing nipple with a short piece of new silicone hose. I've checked to be sure that the turbo housing Port is not clogged or blocked in any way.
If anyone has any ideas as to what's going on here, I would sincerely appreciate hearing them. I'm really at a loss for what's happening. Complicating matters is that this is a track only car without registration so my only opportunity to identify these issues is at the dyno and that is a bit of a hassle never mind the expense.