zonblitz

iTrader: (9)

My past 2 cars were BMW's, manual transmission nice torquey engines and nice handling.

I have had my FD for about 5 weeks now and still I am trying to learn to drive this car effectively.

Just an FYI I have the following mods: Downpipe, cat back, intake, Fluidyne Rad, Alum AST, Silicone hoses, KYB Shocks, Eibach Springs, ACT Racing Clutch, Rotor Sports Racing Stage 2 Engine with 8500 miles now and Defi H20 temp and Boost gauges.


When I accelerate from first to fifth as in taking each gear to 5k or more I have a nice level boost pattern that maxes at about 10 psi and drops to 7-8 then goes up to 11 psi (in 4th or 5th gear).

However, when I am doing lets say 60 mph and I shift into 3rd to pass someone, sometimes I don't get much if any boost. And then tonight on the way to work, I was doing 80 along with another car (a friend of mine) and then went to pass, I shifted into 4th and WOT, I got barely any boost... I then did an old trick that worked well in the BMW and clutched it to try and raise revs but no luck. I finally was up to 6k or so rpms and then shifted to 5th then wala there was my 10-11 psi and I accelerated just fine.

Other notes, at idle on cold engine I am pulling good vacuum, 18-20 in/hg The engine runs great otherwise and when I am steady on Interstate in 4th or 5th, I 99% of the time get 10-11 psi when I get on the gas.

I would appreciate any advice or instruction as to what is a good shifting pattern in association with a good boost pattern and optimal acceleration.


Thanks!

potatochobit

iTrader: (1)

u have a bad solenoid.

i have one too.... it goes away and comes back from time to time... annoying... probably run 300$ to have it fixed by a rx7 mechanic.

zonblitz

iTrader: (9)

Thanks, I'll have it checked out!

rynberg

You have a leak associated with the vacuum chamber.

Also, part of the sequential operation is that once you cross the transition, the turbos will run in non-sequential mode until you drop back below a certain RPM. This is a very noticeable problem with the PFC. You get to experience how laggy and gutless non-sequential will feel on the highway (with a stock cat).

So, my guess is that you have a vacuum chamber leak and you are experiencing a bit of the above as well.

zonblitz

iTrader: (9)

So I have a leak even though I am getting 10-11 psi at some times?

Also will going to a hi-flow cat help solve this?

dgeesaman

iTrader: (7)

A high flow cat will probably increase boost levels, which you're not tuned for. It might increase spool time when you shift at that particular rpm, but that's really not the issue. So I think it's a bad idea unless you also add a boost controller and tune back down to 10 or 11. Your current 11psi is probably fine but more IMO is not.

Have the leaking vacuum fixed - whether it's a sticking solenoid, bad check valve, popped hose, whatever. It could be very easy for the right mechanic - but you need to take it to a rotary mechanic who knows this turbo control system. Or dig in and start troubleshooting yourself.

Dave

zonblitz

iTrader: (9)

I have a power FC I have yet to install but was planning on installing this week once I install new Greddy SMIC.

I have been going to the New Orleans RX7 club recommended mechanic who I am very happy with btw.

I will have him help me troubleshoot as I just got gauges installed a few days ago and have only had 2-3 days to drive car and watch boost.

Thanks for all advice, it is much appreciated and I'll let yall know what we find.

Speed of light

iTrader: (8)

I've had this occur too. Rynberg is correct about the non-sequential mode above a certain point; however, and I stress that this is a big however, there has been a history of the pressure-side turbo control solenoid sticking, and in my experience, the results are far worse than non-sequential operation.

The culprit is the third solenoid back from the from front of the engine (on the lower part of the solenoid rack) and is labeled E in the shop manual. When this sticks, the result is that exhaust is still being routed through both turbines (by the TCA) even though the secondary charge door has closed and its boost is being dumped by the secondary BOV which is now open. Under these circumstances, the primary can't recover and build enough boost to re-open the secondary. This symptom is often intermittent and the result is little or no boost until you get out of it long enough to resynchonize TCA with the rest of the system.

Search on turbo control solenoid and I'm sure you will find lots of information.

Good luck.

zonblitz

iTrader: (9)

wow, great help guys.

These forums rock.

Thanks again.