Boost after 6.5k

[neil_jdmr]

I\'ve only had my car a wek or so but the boost seems to fall off past 6.5k.
 
Its got about 1100 miles on a new rebuild with warranty (my plan B)
 
Now the boost is perfect up to 6.5k ie 10psi the 8 at crossover then back to 10 but tails off with a note change on the engine after 6.5k to about 7psi
 
Now this may be normal but i was under the impression it should pull hard @10psi till red line
 
Any ideas guys let me know
 
Neil

[Jono FD3]

Loose pipe perhaps....... clogged air filter..... nackerd cat???

More than likely the air filter needs a clean or replacing, as mine was asmatic after about 6500 before I changed the filters to K&N\'s!!

Jono

[neil_jdmr]

Iam gonna clean my air filters as soon as i can, they are the same design as the hks superpowerflow thingy\'s but smaller and yellow ( well more black than yellow )
 
I found today that my battery terminals were loose and on further investigation the terminals look too small for the battery connectors. As i was not in a position to do much about it at the time i shimmed the terminals to get a good connection and nipped them up tight.
 
It now seems to boost slightly better, is this a possible cause?
 
I cannot see how the battery terminals can affect my boost issue as its only in the high rpm range?
 
It may just be me wishing it was better but the boost just seemed to hold for longer??
 
What dya think?

[Brett]

:wave  


Firstly, how many miles have your turbos done?  Are you running stock boost?  Is this a twin turbo 3rd gen, or a single turbo 2nd gen?

[neil_jdmr]

Ok mate,
 
95 FD3S
 
Its totally bone standard running standard ecu @ standard boost the turbo system had a total overhaul 1100 miles ago when the engine was rebuilt.

[Brett]

Have you checked for fault codes?

[mattfduk]

if it is stock the boost should drop off at the top end its the way the ecu does it

[neil_jdmr]

Brett,
 
I have\'nt checked for fault codes as it doesnt bring on a cel and tbh it doesnt really seem like a fault just a little breathless.
 
Matt,
 
The boost drops off from 10 psi to about 7-8psi from 6.5 -7k ,i was under the impression it stayed at 10psi till redline

[Brett]

Has it always done it?

[mattfduk]

mine used to tail of at 6k ish when it was standard

[DC-TYPER]

mine is stock and it does this.

[neil_jdmr]

Only had it a fortnight fella,
 
It has always tailed off slightly after 6.5k but it was poor on the second turbo(7psi) until i changed a couple a vac hoses now it pulls at 10 psi until like i say around 6.5-7k then it tails off to around 8psi to redline

[Timmy]

Could this be down to a weak actuator on the second turbo. Don\'t know if you can get uprated items for these turbo\'s.

[neil_jdmr]

Instead of starting a new thread on the same topic i have re-ignited this one as still cannot find a definitive answer on this,
 
My car is bone standard except a hks racing suction kit with two brand new hks elements and a blitz boost gauge.
 
Matt below wrote this and It seems fair enough to me just really wanting to know as have checked just about everything and it still drops off past 6.5k. On my boost gauge im getting 0.8/0.6/0.8 then dropping to 0.6bar to redline.
 

if it is stock the boost should drop off at the top end its the way the ecu does it

Iam now thinking the car is working as it should be but after emailing a  rotary specialist iam back to where i started as they said it should stay at full boost to redline ??
 
I just want it running as mr mazda intended.
 
I have today tried venting the bov to atmosphere incase the hot air from the turbo\'s blowing back down the intake was causing it but still the same.
 
So whats the deal, full boost to redline or factory cars drop off at top end.