1jz cressida not boosting over 11psi

[Mr DOHC]

i have been having boost spiking issues lately, so i decided to put it back to wastegate pressure which with my mods should be around 14-15 psi, but it wont go over 11psi, any ideas

[whatthe?]

Have you run it at wastegate pressure before to confirm that it should make 14psi or are you just assuming? I take it the spiking issue is gone now?

Aside from that, boost leak? Blocked cat?

[Mr DOHC]

well most ppl with a cooler and 3 inch exhaust alone have boost cut issues at 15psi

spiking now gone, so has the power.

the "problem" went away as soon as i put the boost controller back on

[whatthe?]

So with the boost controller in it makes boost without issue but it spikes, and without it in it wont make over 11psi?

Doesnt sound like a boost leak or blocked cat then. Maybe your actuators are just more effective than those of others with the same mods?

It's probably a bit hard to call it an issue if you havent run it the same way before as a comparison

[Mr DOHC]

So with the boost controller in it makes boost without issue but it spikes, and without it in it wont make over 11psi?

Doesnt sound like a boost leak or blocked cat then. Maybe your actuators are just more effective than those of others with the same mods?

It's probably a bit hard to call it an issue if you havent run it the same way before as a comparison

it used to run 17psi no worries with the controller


what do u mean

you havent run it the same way before as a comparison

run what the same way, when i just had the 3 inch exhaust and THATS IT, it ran 11psi, but then i got the boost controller

[The Real Roadrunner]

sometimes they wont make more boost just by fitting a cooler (most do but not all)

if you had it running 11psi with the exhaust and then put the cooler on did it raise the boost to 15psi?

if your losing power up top with the cotroller and 17psi it could be a fuxored cat or collapsed muffler but the only way to tell is pulling it apart for visual inspection or plumb in a fitting in the dump to a pressure guage and check exhaust backpressure throughout the revrange.

cheers
linden

[Mr DOHC]

ok, i think i have confused u all

ppl with the same mods as me usually hit 14-15psi naturally, i can only hit 11psi

i used to be able to hit 17psi reliably with the boost controller, i dropped the pressure when summer came along, now i wanna put it back up and it wont go up it just spikes harder,

it doesnt really stress me, but my dad is coming to town while i am away and he's gonna be driving it, so i dont want it to be hitting fuel cut, but i also want it to be at full potential.

[JP]

my manual JZX81 with 3" exhaust from turbo's and ARE FMIC used to run about 10.4psi on wastegate pressure according to the dyno log.

I put the figures into excel from my chaser with non-vvti 1jz and my wagon with vvti 1jz here:
http://users.tpg.com.au/adsl0uxv/dynoresults.xls

[thechuckster]

it doesnt really stress me, but my dad is coming to town while i am away and he's gonna be driving it, so i dont want it to be hitting fuel cut, but i also want it to be at full potential.

wtf! you want to loan your drag-racing dad your car?

if i loaned a parent my car, i'd turn the boost down so it gets returned not overly rooted.

There's nothing more dangerous (except a nun with a driver's licence) and mechanically destructive than a parent with a lead foot.

[1JZ.747]

1j's fuck cats, plain and simple. pull it out i bet its melted and fucked, the newcastle crew we used to get less than a year out of them

[Mr DOHC]

wtf! you want to loan your drag-racing dad your car?

if i loaned a parent my car, i'd turn the boost down so it gets returned not overly rooted.

There's nothing more dangerous (except a nun with a driver's licence) and mechanically destructive than a parent with a lead foot.

ahhahahaha, my dad has 5 cars, a 355ci VP maloo with 220+rwkw, a genuine 215i VR senator a VX series II SV300, a VE GTS 307kw and a 408 cube E55 Charger, i think he can handle a cressida

would the fucked cat be the spiking issue, or would that be something else.

[fatboy13]

pics of charger or ban

also my 1J only runs 11.5psi with cooler, dumps and 3inch exhaust and no cat....

[Mr DOHC]

heres a pic of a poster i have, this was taken back in the late 80's when it was all original, it came off the road in 1993 and will be re registered this year. apparently this is a rare colour :S

the pic was quite a bad copy, jack all colour