Not Holding Boost

[Ruffels]

hi guys, just wanting to bounce some questions off you guys, see if i can get any responses that could help my situation

ive got all the usual mods that SHOULD make mid - high 200's (rwkw) but i'm not getting there because the boost is not holding and my coilpacks are breaking down... now the coilpacks are an easy fix, but i dont know how to fix the boosting issue.

i'm looking for it to be running anything in the range of 17-19 psi... the boost quickly spikes to 17psi... but then drops immediatly to 12psi and holds there

i've had some people sugest its;

* the rubber intake shutting closed, and i need a metal intake pipe (even though ive done the rev210 mod)

* the std. bov leaking

* the wastegate actuator spring not strong enough (even though its supposed to be a 14psi actuator, and i've pulled as much preload out of it as possible)

* i need to run an electronic boost controller, because a turbotech just wont cut it

* my coilpacks are failing and breaking down at high rpm/boost levels (i have a new set of split fires on their way) and this will cause boost to drop off as engine is not getting full spark

for reference sake the turbo is a custom job from hypergear,

it's basically a 3076 squeazed into a std comp housing an aftermarket 0.63 turbine housing the breakdown of the turbo is as follows;

- standard r33 comp housing thats been machined out to accept a 76mm exducer in 52 trim, oil and water journal bearing CHRA, 0.63 rear housing with 68 trim and with 30mm internal wastegate hole, and a "high pressure" (14ish psi) actuator

does anyone have any idea other then those ideas listed above, why its not holding anything higher then 12psi?

[kwickr33]

I thought Stao is coming to see you in person next week. can you post your boost curve? Boost drop unless vacuum leak will not cause engine to break down.

[boostn0199]

To rule out the bov block it and see if it helps but should not leak at that boost.

I would go full metal intake because it could stil be geting shut on the stright part where you have not added the pipe into.

for a quick fix with the coil packs get some bcpres7s if your not already running them and gap it down low until it stops missing just to test it out.

Yes it would be better to run a ebc but I have seen the boost tees hold up just fine in high power aplications so I doubt it that so check for leaks aswell. I have a hypergear turbo aswell witha 0.63 rear and it drops off from 17.5 to about 15 at redline and thats with a 14psi acutator but yeah it should not be going to 12 like in your case.

[Ruffels]

yeah, im yet to block the bov to test it

i'm running bcpr7es 8mm gapped

im thinking about engineering my own metal intake as there is nothing really available off the shelf

[geraus]

yes there is, im using a metal intake pipe from Authobhan 888 his pipes are good im using them now on high boost 17psi

[geraus]

http://www.autobahn88.com/english/

[Ruffels]

no offense but that intake pipe looks terrible... doesnt look like the standard one in the slightest

should be more like this but obviously in metal

Edited April 18, 2010 by Ruffels

[boostn0199]

well as you said go custom then itll end up cheaper if your handy with a welder

[SS8_Gohan]

i wouldn't stuff around with intakes if you've done the rev210 mod

even at .63 rear you won't get flat boost curve... Trent and i have tried heaps of different things. Swapped out BOV's, run i don't know how many actuators, i've got arguably the best aftermarket EBC, Blitz Spec-R, rev210 mod, etc etc.

Currently have such a beefy actuator in there at the moment that it runs 18psi with the Blitz turned off.

.63's will drop about 2-3psi at redline. That's just the way it is. And you'll find similar sized turbo's from HKS etc will have very similar boost curves.

You've probably got a few psi to pick up, but i still think at the end of the day, you'll get up to around 14psi at redline and that will be normal.

Do the splitfires, see how it goes, and then sus things out a bit further.

Also, i really don't think running 14psi at redline, after peaking at 17psi is really such a bad thing if your engine isn't built

How's doing the work/tuning?

[boostn0199]

i wouldn't stuff around with intakes if you've done the rev210 mod

even at .63 rear you won't get flat boost curve... Trent and i have tried heaps of different things. Swapped out BOV's, run i don't know how many actuators, i've got arguably the best aftermarket EBC, Blitz Spec-R, rev210 mod, etc etc.

Currently have such a beefy actuator in there at the moment that it runs 18psi with the Blitz turned off.

.63's will drop about 2-3psi at redline. That's just the way it is. And you'll find similar sized turbo's from HKS etc will have very similar boost curves.

You've probably got a few psi to pick up, but i still think at the end of the day, you'll get up to around 14psi at redline and that will be normal.

Do the splitfires, see how it goes, and then sus things out a bit further.

Also, i really don't think running 14psi at redline, after peaking at 17psi is really such a bad thing if your engine isn't built

How's doing the work/tuning?

Yeah thats correct you wont get flat but yeah around the 14 mark is what you will get at redline trent told me the same thing the 0.63 makes it drop down and as you said its not a bad thing to be a couple of psi down at redline

[hypergear]

You can still do it with internal gate by limiting the amount of exhaust pressure that you want to dispatch. Well nothing is impossible.

[Ruffels]

i wouldn't stuff around with intakes if you've done the rev210 mod

even at .63 rear you won't get flat boost curve... Trent and i have tried heaps of different things. Swapped out BOV's, run i don't know how many actuators, i've got arguably the best aftermarket EBC, Blitz Spec-R, rev210 mod, etc etc.

Currently have such a beefy actuator in there at the moment that it runs 18psi with the Blitz turned off.

.63's will drop about 2-3psi at redline. That's just the way it is. And you'll find similar sized turbo's from HKS etc will have very similar boost curves.

You've probably got a few psi to pick up, but i still think at the end of the day, you'll get up to around 14psi at redline and that will be normal.

Do the splitfires, see how it goes, and then sus things out a bit further.

Also, i really don't think running 14psi at redline, after peaking at 17psi is really such a bad thing if your engine isn't built

How's doing the work/tuning?

I've done all of the work, but trent has tuned it

[Ruffels]

You can still do it with internal gate by limiting the amount of exhaust pressure that you want to dispatch. Well nothing is impossible.

im not entirelty convinced by this stao, iv'e effectivly done what this device does because i have around 12mm of preload (eg shitloads) i dont think there is much extension in the rod left... any more preload (there is no thread left on the rod anyways) and it will probably wont open at all...

[R31Nismoid]

Just get trent to force the gate closed the do a careful run up. If its dropping immediately from 17psi then you'll have an easy cross over point, will rule out actuators etc.

If it drops regardless, it's the turbo. If it doesnt drop its something else

[DVS JEZ]

is that always 100percent true? if it drops regardless its the turbo?

is it possuble that there is a restriction still?

[DVS JEZ]

have you tried decat?

[femno]

i'm looking for it to be running anything in the range of 17-19 psi... the boost quickly spikes to 17psi... but then drops immediatly to 12psi and holds there

This is interesting. So you effectively have a flatline 12psi boost curve? Not taking into account the 17psi spike?

2 problems.

You have too much gate preload. Gate preload adjusts the ramp of the boost, not neccessarily the peak boost. Too much and you get a nasty spike. Not enough and it builds boost too slowly.

What is the boost controller doing exactly? Is it wound all the way in? Does it give any adjustability? Theres no reason why it wont work.

If its wound all the way in and giving the 12psi then the signal line to the controller needs to be restricted.

Its simple boost setup really.

...and dont expect a flatline 17-19psi boost curve. Its still a small rear housing.

[R31Nismoid]

is that always 100percent true? if it drops regardless its the turbo?

is it possuble that there is a restriction still?

Well im assuming the exhaust has been dropped just to be certain

If not that can be done at the same time as everything... but immediate drop is suggesting otherwise as it wouldn't just "drop" harshly

[kwickr33]

Just noticed your said the boost dropped to 12 psi "immediately"

usually boost drops slowly as back pressure increases gradually. This "immediate" drop might be a EBC related thing.

Get Stao to bring one of his manual boost controllers and test it out.

[Ruffels]

my new splitfires arrived today , tomorrow after work i'll throw them in and see if that changes things, as the top end missfire has been getting worse... im sure the missfires wont help my boost issues