Got a issue I cant figure out. It's hard to describe but will do my best and it happens about 50% of my shifts.

If I do a fast shift and staying in the rev range for the 2nd turbo the 2nd turbo won't come online again and I will just get 2psi boost from the small turbo. But if I shift slow so that I go down on the rev range for the small turbo and apply throttle again it works like a charm every time.

What could be the cause of this? Swapped my turbos (big one was dead), swapped 1way valves and most of the vaccume tubing while at it but still have the same issue.

Car is almost stock. Got a apexi intake, RA smic, straight pipe after stock JDM downpipe

 

First off, the turbos are the exact same size. Front is the primary turbo, rear is the secondary turbo.

Most likely it's something with the turbo control actuator system, probably a lazy solenoid. I had a lazy TCA solenoid a while back that did pretty much the same thing - swapped it out, problem was gone.

Dale

 

Yea that does sound like it could be the issue. Out driving now (Food stop) and I notice if I do extremely quick shifts that secondary turbo stays online.


Yea your right about the size on the turbos I just tend to say small and big cause it's easyer for non rx7 people to understand :p

 

That or a leaky check valve, pressure chamber, or vacuum chamber. Test them all per the factory service manual.

 

Got brand new check valves from daleclark so they cant be the issue but going to check the tanks.
A bit off but still relevant if I would go the non sequential way with stock twins will it affect the emissions? Need to stay within emission standards for the car to be road legal in Sweden

 

It shouldn't. I wouldn't go non-sequential, you have a pretty minor boost problem. Non-sequential will just kill your low end. Keep at it and solve the problem

Dale

 

Going to stay sequential just wondering cause a tuner here says that he can get more whp from a non sequential system. So was just wondering.

 

You can make more peak at the cost of response and low end power.

If you want more power than the twins can provide, go with a good single.

Dale

 

Cant go singel cause of mot but BNR twins is the next thing