Dropping Boost. Cant Find Why

[R33GOD]

just curious to see how much preload people are running on their ajustable actuators.

i had a problem of apparently not running enough which is why my hiflow could only hold boost at 13 psi.

im getting a retune next week. from 3/4 of a hole of preload i have now loaded it up to 1.8 holes.

what do u guys reccommend as safe preload on a rb25 bush bearing hiflow or any type of hiflow

thanks

Edited April 21, 2008 by R33GOD

[R33GOD]

anyone know this question?

[RedDrifter]

Simply, the more preload the more boost.

Ive messed around with mine on the GTRS tubo and have it preloaded to run 18psi atm. I ran it for a weekend with the preload to run 25psi and it held the boost perfectly. Just shorten it till you get your desired boost level and see how you go.

[limpus]

RedDrifter is pretty much spot on...just keep shortening the rod...you will find that as you shorten the rod boost response improves...it will reach a point when it will be optimum and shortening the rod more will cause boost to spike...from there you can raise your boost further by using a boost controller...while shortening the rod more will give a higher max boost...it will probably start to spike more too...plus what you really want is for the wastegate flap to stay shut till you reach your desired boost level which won't be the case if you continue shortening the rod as the flap will start to creep open at some point...

I'd be more inclined to adjust the length of the rod till you get good boost response without spiking...then raise the boost with a boost controller...

[R33GOD]

it spikes to 15 with the rod ajusted to 1.8 holes then comes back down to 12psi. if i tighten it more should the spike be lower and it will hold say 13-14 psi?

but dosent shortening the rod kill the turbo also? shouldnt the boost controller do the rest? or is the reason why its spiking is because i need to tighten more?

confused

[R31Nismoid]

How does it kill the turbo?

Its just controlling the actuator. A turbo makes boost, thats it. Only thing that will kill is it objects that shouldnt be there or poor oil/water supply etc.

Gate preload works the same as ext gates and spring rates.

Spiking will be due to the fact its int gate, get a boost controller. Sometimes spiking cant be controlled just off the actuator accurately depending on the setup of the int gate, how big the hole is and so on

[bnr#@]

If its spiking you need to loosen it...

[R33GOD]

ive got a hdi boost controller in it now but i have to get it retuned so i can up the boost more. i just dont get it. its a hiflow. how come its droppin boost so much even though the preload is set at nearly 2 holes. grrrrrrrr

[limpus]

It might not actually be "dropping" boost like you think...its probably set to run 12psi and its spiking to 15psi...try lengthening the rod and then upping the boost via the boost controller...although bear in mind that a slight spike is normal as it is a mechanical system and it needs time to stabilize...

[R33GOD]

i think your right. cause it drops very slow then gets stable at 12psi at around 6000rpm.

il just leave it the way it is for now until i get retuned.

[R33GOD]

car will not hold boost at all. we tried ramping it up to 20psi but still drops down to 13 psi. damn this car.

these are the turbo specs i got from mtq

Exhaust side

.63 a/r

51.00mm exd.

Comp side.

.60 a/r

55.4mm ind.

preload was set to 2 holes also!!!

wtf is going on

[SXR]

possible turbo fault....seen few hi-flows dropping boost.

[R33GOD]

got the problem fixed. leak in the boost controller fitting. we reached 14 psi by redline. tuner said i need a ebc to hold more boost in future.

result 221.5rwk on 14 psi. on 11.7-1 a/f ratio. nice n safe

[R31Nismoid]

[R33GOD]

hopefully its good for a highhhh 12 next friday

[dangerman4]

Spiking will be due to the fact its int gate

think before you type.

thats a load of crap....

[RedDrifter]

Good to see the cuase was found.

Those boost leaks suck donkey.

[Al]

think before you type.

thats a load of crap....

That's what i was thinking to myself

No spike here: GT30R-IW

[R31Nismoid]

think before you type.

thats a load of crap....

read the part after the comma please, matter of fact... read the sentence after it as well while your there.

it said (incase you still miss it)

get a boost controller

And what did he post later on? He needs a EBC to help control the boost.

Funny that. Picking one section of an entire post is useless when the rest of the post gets the point across.

Maybe read posts twice before you type?

[miragev]

it spikes to 15 with the rod ajusted to 1.8 holes then comes back down to 12psi. if i tighten it more should the spike be lower and it will hold say 13-14 psi?

but dosent shortening the rod kill the turbo also? shouldnt the boost controller do the rest? or is the reason why its spiking is because i need to tighten more?

confused

whats 1.8 holes ???

i have about 8-9mm preload on my 2530 turbos on my 32gtr any less and it won't hold boost even on low psi

i have just got a new set of uprated hks actuators so we'll see how much preload i need to put on these

even with 8mm preload on the standard actuators that came with the 2530's they still open at 13psi without the boost controller switched on i can't believe how much force is behind the wastegates even at 3-4 psi of boost