Huge Boost Creep

[R34GTFOUR]

have you tried disconnecting the external gate??

or

dropping the exhaust from the catback??

...... jks dont hurt me haha

i would be pulling the manifold off and getting it checked by kyle if possible

[AD4M]

this isnt the first 6 boost manifold i've heard of with this issue. not to slander 6boost's work but i know of a std rb26 running a 6boost mani,tial 44 and gt3582 and it sky rocketed to 24psi every run! the problem lies in the collector where the gate is picked up from..

im confused as to how removing the exhaust will help lower boost, a restriction will SLOW the exhaust wheel down creating less boost pressure.. i speak first hand on that as i've experienced just that with a blocked cat.

if you've completly removed the gate and its still boosting then i think you have your answer haha

[AD4M]

oh and best way to fix it is to have the gate almost on the mani or close as possible!

[Finny]

Sorry if this has already been sujested.

I use to get HUGE boost spikes over around 4000rpm. I changed turbos and wastegates 3 times and still had the same issues. Had a thread on here to see if any one had any ideas.

It ended up being the igniter wasn't earthed properly which inturn gave me very retarted timing. If the timing is retarted the fuel/air will still be conbusting when the exhaust valve opens which spools the turbo up like crazy.

My wategate isn't as big as yours and I am running a heavily modified RB30DET and if my timing is too retarted I get the same issue. Try advancing your base timing to see if that helps or advancing it up top where you get the boost spiking on your ECU. Also make sure your igniter has a good earth, mine was screwed into the stock plastic cover but I had to run an extra earth wire to get it to work properly.

I can also retard my timing and see 30psi of boost with the wastegate perm open. advance the timing back to 15degrese or so and its fixed.

Edited April 21, 2008 by Finny

[Gts-t]

nice work ^^

[psi]

Lets get this right..

you totally removed the WG from the car, then drove it. and the thing still wants to overboost with a great hole in the side of the manifold where the WG is spose to be?

If that is the case, you have some issues..

Like the guys above said, really bad timing and to much fuel.. or extremely poor WG pick up port.

I had the wastegate port issue on an ebay manifold. Totally crap pick up port. moved it, rewelded it 3 times, and then ported the daylights out of it to find out i had to move it yet again...

Would have been quicker to build a proper one from srcatch!

[Al]

Had a chat to my mechanic and Andriano is partly right.

Even though i have a similar setup, with the same size ext housing on the turbo, you are running a bigger hp turbo, thus having a bigger ext wheel. The bigger wheel in the same size housing will not allow enough air to flow past through the housing without spinning the wheel faster and faster.

Two options: Upgrade to a 1.06a/r ext housing, will also give you better top end, or "bleed off" more gases (ie: larger feed to gate and larger gate or run 2 gates)

Either way not really the "fault" of the manifold design

[Finny]

I woulnd't blame the turbo.... I have a KKR560, .69 A/R rear and the internal wastegate is like 1 inch wide if that.

I had problems with my old KKR480 as it had a slightly worse wastegate design. But even still every one said the KKR480s over boost, I just ran 18 degrease timing and didn't have a problem.

Suppose I don't have to worry about that though as my RB30DET was built with low compression because I wanted a free running engine. Which was a VERY good idea in my case because I have had the engine for only 4 months and I have snapped the cam belt tentioner off once and the cam belt its self snapped about a month later. I love it when my valves are all the way down the piston can come up to top dead centre and it doesn't touch the valves ....

[VB-]

just to clarify, car went on the dyno a couple of hours ago, no gate at all we saw ~13psi, then backed off again as it didnt flatten out, it just kept going up and up.

nismoid, and other expressing the same opinions, the exhaust was dropped, and oh my god, YOU WONT BELIEVE WHAT HAPPENED...... nothing. nice try though guys, your wealth of experience shines through again.... still waiting on that explanation as to how a restrictive exhaust will cause creeping?

kyle himself has said there is a number of factors, and that we should try a bigger gate etc, f*ck knows why but hes pretty assertive that his manifold is fine and we should either put on a restrictive exhuast and/or weld the gate to the exhaust housing...

for those who say the gate is too small, an XR6T, although it has a bigger exhaust housing, is still a 4L motor and can be held so low (like 4psi) by its little internal gate, theres no way a 44mm exernal, atmo venting gate cant hold this thing to 15psi

[R34NRG]

blue = with gate

red = without gate

next step is possibly redesigning the manifold, getting a new one.

Edited April 21, 2008 by R34NRG

[Adriano]

Do you have the same printout with A/F ratios?

[R34NRG]

Do you have the same printout with A/F ratios?

unfortunately no...........was kinda a 2min thing....didnt think to grab it

[SXR]

its running around 11.1....didnt bother with too much on afr as long as i knew it was safe to run

[paulr33]

my $ is on its location, if you weld it to the exhaust housing its probably your best bet, basically it seems when it opens, it cant divert enough back pressure, which results in unlimited boost

[GeeTR]

It ended up being the igniter wasn't earthed properly which inturn gave me very retarted timing. If the timing is retarted the fuel/air will still be conbusting when the exhaust valve opens which spools the turbo up like crazy.

My wategate....

^^ Most interesting post iv read in months. Very nice work!

[Al]

I woulnd't blame the turbo.... I have a KKR560, .69 A/R rear and the internal wastegate is like 1 inch wide if that.

Completely different turbo mate.

Ever wonder why KKR turbos are so laggy? They are built cheaply with huge clearances and inefficient turbine designs.

I am talking about the internal clearance between ext wheel and ext. housing. As the ext. wheel is pretty big for a small housing you will have boost control issues. The only way to solve the issue is to slow the gases going into the turbo, whether my timing adjustment or by bleeding off more exhaust gases.

Have a chat to Kyp at ATP, he is Victoria's No.1 turbo guru.

Have you compared the trim specs from an XR6 turbo to this turbo? You'll probably find a few differences, so pretty pointless comparing the two

[6BOOST]

this isnt the ideal way but physically theres no room....also i have been fitting it this way on all 6boost manifold and never had an issue

HOLY.......f**k

You mean to tell me, after all these problems, and all the calls, that I was just silly enough not to ask if you had mounted the gate off the manifold with the SUPPLIED f**kING BEND??!!! The picture tells the exact reason you have bloody boost creep issues!! Did I supply it with a 90 degree bend and some straight pipe?? NOOOO!!!!! Because you have a manifold that is so efficient that under NO CIRCUMSTANCES should you mount the gate more than 50mm away unless you have a 60mm gate!

Tell you what, wish I had of known this sooner, I would have told you to just chop the gate pipe off in the car without removing anything and given it a run. Hey presto, boost control! There is room to mount the gate up high, if I can fit a GT42 and 4" dump with a 44mm gate up high, you can fit one as well, keeping the ABS and all. 2 whole threads on this same subject and finally, an answer. Andrew, DO NOT mount the gate down there, and you will have no issues.

6BOOST

[SimonR32]

no offence to you kyle, have one of your manifolds and love it, works a treat (after some mods)...

but every one of your manifolds that i have dealt with have boost creep problems and there have been several, this is not a one off

problem seems to be a combination of manifolds being so efficient at the collector, 90 degree angle of the gate pipe off the collector and size of pipe used for this pipe. its a simple fix.

it seems unreasonable that the pipe used to connect the gate by you is usually much smaller than the size of gates people use, you should look at putting a larger 50mm pipe on a upwards angle, going slightly with the flow (not 90 degrees to the direction of flow).

on topic now: yes gate placement is stupid in this case and making the problem very bad, as kyle said mount the gate close to the manifold not down low...

[DRIFTER]

i don't have any boost creep problems with my 6boost manifold.

can't believe people thought that removing the exhaust would help.

[6BOOST]

No offence taken, however to highlight the points you just raised, my gate outlet comes off the collector at 30deg, I cut every single one of them and put in a big box with my drop saw every few weeks, so I know the angle, maybe you haven't taken notice before. Secondly to that, the gate outlet pipe is 42mm id. A Tial 44mm gate(most common I and my customers seem to use) is measured at the valve, not the hole in the inlet, which is actually around 41mm or the same as the outlet pipe. The other most common gate is the turbosmart 48mm, which as a 45mm hole in the inlet flange, again, only 1.5mm per side bigger than the pipe I use, there is no such thing as 50mm pipe. Conversly, the next size up pipe has a diameter of 54-55mm ID, its so big that the gates we are talking about, the flange would fit INSIDE the gate outlet. This in my eyes would cause massive turbulence into the gate... Would the bigger outlet pipe make up for any downsides to the flange transition?? I don't know.

Simple fact is, if anyone has a probem with boost control, calls me, and actually listens to what I have to say, rather than just look for someone to blame, rarely can you not get a workable result easily. Its just most people want to listen to the advise of others, rather than the designer of the product who has done over 1000 manifolds and encountered every problem first hand along the way. Often removing one of the springs in the 1 bar gates helps, as does a change of cam timing, and also putting a proper cat in, the back pressure reduces boost. Simply put, if you want to run your car like a race car with a 3.5"+ exhaust, no cat and 1 muffler, then run a race style 50-60mm gate, don't expect to use the best manifold on the market thats is designed to stop turbulence, reversion and increase velocity, and expect to use a street style(for the application) 40-45mm gate.

6BOOST