Ok my primary turbo boosts up to what it's set at on the PFC (.80) and holds that fine up untill the transition, once the secondary kicks in there is NO HOPE of the car holding boost. It has spiked as high as 1.02 on the PFC. So right now I just don't floor it, I am looking into getting the wastegate ported but is there anything else I can do? And do any of you have any thoughts as to why the car can hold boost fine up untill the secondary kicks in? Thanks very much.
-Nic

 

What are your mods? That's a pretty big spike!

 

I used to run more boost all the time on the twins ...with pump gas. What mods do you have?

 

Here is a list of the performance mods on the car...

- B&M Short shifter
- ACT street/strip with hd pressure plate & stainless clutch line
- reasonated midpipe
- hose job
- PFS exhaust
- PFS boost gauge
- greddy turbo timer
- greddy SMIC with Pettit intake duct & SPAL fan
- Greddy 2 piece kit & Elbow
- Hard pipes
- Apexi intake
- stillen cadmium cross drilled rotors
- Hawk HPS pads x 4
- downpipe
- Cusco strut tower bar
- Apexi PFC
- Efini Y-Pipe
- Walbro 255 fuel pump
- AST elimination

The car was dyno tuned using the PFC by Don Marvel at Marvelspeed here in Texas, but that was with a highflow cat on, not the midpipe which is on now.

 

thats your problem right there....the midpipe. Either put the HF cat back on or port ur wastegate and you should be able to control boost again.

 

I agree that by adding the mid pipe after tuning with the cat is your spiking problem, but I would add a Boost controller like Profec B.

 

You could always muck around with the secondary spool control via a tap but that takes time to balance out so would say the mid pipe would be the way to go

 

would you guys suggest I put the stock cat back on untill I get the problem resolved? I don't understand why adding a profec-B would do me any good, is the boost control system on the PFC insufficient? I drove another RX7 today and it has a ported wastegate and held boost PERFECT, it was kinda pissing me off haha. But after driving that car I think I am convinced to port mine. But can someone please explain what the benifit would be to adding another boost controller, it just doesn't make much sense to me. Thank you very much
-Nic

 

all Boost controllers move the wastegate to control boost....getting a different boost controller won't solve the problem that your wastegate isnt big enough to vent enough exhaust and keep the boost level down. Put your high flow cat back on or port the wastegate and you should be fine

-Zach

 

Guys, he is SPIKING, not CREEPING.

Either adjust the PFC duty cycles to better control the spike or buy a real boost controller. An aftermarket electronic boost controller will likely do a much better job at controlling the wastegate than the PFC (which uses the stock solenoids).

Like Radical Rotary Avantgard said, get a boost controller. If you experience problems with CREEPING after doing so, then yes, you will need to port the wastegate or put the hi-flow back on.

In either case, you should take the car back to Marvel and have them tune the car for the midpipe. Should be small adjustments.

 

the profec should solve the probs.

 

Thanks for the advice guys but can anyone explain why the car only has a probem holding boost once the secondary kicks in? Or give a best guess anyway...

 

you can use restrictor plates to lower your boost a bit. as for why its not holding boost, the second turbo came online obviously