rxmiles

iTrader: (11)

Hey guys, so after finally being able to pass emissions I finally had a chance to drive the car a bit. I'm a bit concerned as my primary hits a steady 15psi and then at switch over boost levels stay at 10psi. The car is about 98% stock with the exception of a downpipe and a drop in filter.

I am not having any issues whatsoever with the extra boost, it actually runs and drives great and pulls like a freight train. I redid all my vacuum lines w/ silicone, had the injectors serviced by RC, and replaced some couplers.

I live by the mile high city, so altitude is a considering factor.

adam c

iTrader: (2)

My first thought would be a partially clogged cat. Is it the original cat? You could try removing it, and shaking out whatever debris that may be in there. It isnt that hard to do.

94VRotary

iTrader: (6)

Isn't it dangerous to pull 15 psi on stock car?
I didn't think stock ecu can handle boost above 12 psi.

TomU

iTrader: (11)

When you replaced your vac hoses, did you test your solenoids and actuators? I was getting healthy boost and eventually got around to testing the control system. 4 or so solenoids and my turbo actuator were all toast (solenoids would open cold, but not hot)

rxmiles

iTrader: (11)

I have actually used two different cats on the car for my emissions tests. Both unclogged and the newer one has >10,000 miles.

I've done some reading and there's a safety threshold that the stock ECU can handle the additional boost. I guess it's when the boost spikes when it can be dangerous. Car feels great.

I did test all my rats nest solenoids, I went through the system about three times because I had no secondary boost.

Tom93R1

iTrader: (2)

When I lived in Colorado Springs with a mostly stock car my boost was more like 12-13 on primary and 10 secondary. I installed some bleeder valves in the charge control activators and was able to fine tune it back to something very close to 10-8-10. I'm amaze this page is still up after so many years: https://robrobinette.com/boost_controller.htm

TomU

iTrader: (11)

port the wastegate and get a PFC

furious_rotation

Not here to be negative. If you get a true 15 psi from the twins, which is what it sounds like you are trying to achieve, on the factory ECU. You are begging to blow her up. The old list of mod restrictions for the factory setup is FD 101. Dial it in to 12 psi max or install a PFC and have it tuned. Don't be a victim

Tom93R1

iTrader: (2)

15psi on primary turbo and 10 on secondary boost is not wastegate porting issue and PFC will only fix it if you know how to tune the boost control pattern. Not a big deal, but it's not just a swap and be done with it fix.

TomU

iTrader: (11)

... or map more fuel

K-Tune

iTrader: (26)

Overboost on the primary turbo with a stock setup could be caused by the turbo precontrol circuit. In stock config the wastegate doesn't start opening until after the secondary transition, the precontrol is used to throttle the primary turbo while sending what would be "waste" exhaust to the secondary to prespool it.

Make sure the vac lines are routed properly as well as restrictors installed correctly...

rxmiles

iTrader: (11)

I'm already getting 15psi on my primary, I'm trying to figure out if I should restrict it to the base 10psi.

I was reading this thread: https://www.rx7club.com/3rd-generati...n-myth-934461/

There's different variables in which the "system" can account for additional pressure according to his data. Perhaps is the altitude at which I'm at.

96fd3s

IMO the goal is to avoid fuel cut. When your hitting fuel cut your in unsafe territory.

Where fuel cut occours is dependent on a variety of things including load/boost at a given RPM, and gear (i think?), no doubt air intake temp and several other factors. Theres a graph somewhere showing fuel cut vs rpm/load..and its in no way linear.

For example the fuel cut psi thresh hold will be higher at lower RPM and in lower gears.

(so basically, for example only, you could potentially run 15psi, UNDER 4k rpm, in gears 3rd and lower and still be under the stock ECU's safe max and never see fuel cut). im making those numbers up just for example.

IMO the 10-8-10 thing is slightly misleading as the stock ECU does allow more boost under certain load situations & rpms.(not much more) Whats important is at what RPM the 10-8-10 occours.
e.g. if it spikes to 12psi straight away on the first turbo, drops to 10psi or a bit below before transition then the rest goes as planned then that would be OK.