Boost Falling..

[krush]

hey all, ive searched the forum, but everything was a bit different, or to do with r33's (while i have a 32) and stuff.

ok, i bought a turbotech, installed it today. but thats only got a little to do with this.

pre-install:

would boost to .8bar at 3000rpm, then drop to .6bar by redline.

mid-install:

put the turbotech unit in, but removed the ball/spring (as i was having problems ealrier). with the little hole in the side of the unit, its kinda acting like a bleeder valve, now boosting .9bar at 3000rpm, then dropping to 0.7bar by redline.

post install:

put the ball/spring back in and starting turning it slightly as per instructions on how to get more boost.

boosts to 1.0bar at 3000rpm, then drops to .8bar by redline.

im guessing the turbotech is working fine (since it has the same drop in boost regardless of how it was setup), so what is causing this drop?

carspecs:

r32, rb20det

pod filter, cat back exhaust, hks bov.

could it be the stock dump pipe not flowing enough? i dont really wanna go messing around with boost when i dont have a solid knowledge of whats going on exactally.

any opinions of help would be greatly appreciated, as for now ill just take it out run .8bar max..

shaun.

[Cubes]

No FMIC?

Its common for the R32's to drop boost.

I fitted an EBC that learns the boost curve and adjusts duty cycle to achieve the desired boost level. This had the turbo holding boost. BUT from 12.5psi to 15psi it only picked up 10rwkw. Obviously the turbo was in to choke and out of efficiency.

One reason why the turbo was most probably dropping boost.

I later removed the EBC and elongated the wastegate actuator holes, this allowed me to pull the actuator away from the turbo essentially reducing the amount of travel the wastegate has. This increases boost and was able to hold 16psi to redline. It worked well on the rb20det.

However, now on the rb30det it makes zero difference, it will not hold any more than 8-9psi at peak power.

However it did make good peak power on that boost level, once again that indicates its all about airflow not boost.

[krush]

thanks for the reply cubes

nah no front mount yet, its bolted on but im yet to do the piping for it, hopefully get that done on my next long weekend in a few weeks, IF something else doesnt come up..

something regarding the turbotech, i was under the impression that it would hold constant boost because if boost was to drop, the turbotech would close off supply to the wastegate until it boosted back up again?

now just thinking more, the boost line to the turbotech is from the compressor housing. if i were to supply boost from the plenum, then it would hold more constant boost, at the expense of the turbo spooling more and more to supply X amount of boost to overcome the lack of efficency between the turbo and plenum in my whole setup, right?

hmmm. so basically i have to get it all flowing free (dumppipe and hookup my intercooler i suspect) to get it holding a more constant, non threatening (for the turbo) boost level. theres nothing wrong with my turbo (i hope) or the turbotech i guess?

i think im answering my own questions, but support and confirmations would make me feel better

shaun.

[Cubes]

Sounds as if u are on the right track.

I have yet to try the plenum feed.