Huge Boost Creep

[Al]

Not sure on cost, but you have a new ext. housing (ie: new turbo), so you should get a good trade as 0.86a/r housings are very popular, thus can be resold very easily.

Give your turbo supplier a call and see if they are willing to trade, with cash adjustment, or give Kyp at ATP a call.

Nope Matt's is definitely a GT30, same as mine on my 3.0ltr. Hence why we want to drive each others cars to feel the difference between the 2.5ltr and 3.0ltr engine, as our engines almost have identical bolt on parts.

[VB-]

what manifold/gate do you run al?

[R34NRG]

Not sure on cost, but you have a new ext. housing (ie: new turbo), so you should get a good trade as 0.86a/r housings are very popular, thus can be resold very easily.

Give your turbo supplier a call and see if they are willing to trade, with cash adjustment, or give Kyp at ATP a call.

Nope Matt's is definitely a GT30, same as mine on my 3.0ltr. Hence why we want to drive each others cars to feel the difference between the 2.5ltr and 3.0ltr engine, as our engines almost have identical bolt on parts.

where abouts are u located in al? id be very interested in meeting up with u guys when my cars done to have a look.

but yeh ill defiently give my turbo supplier a call, and ATP.

is your car running yet?

[Al]

Car was running, but currently being stripped and rebuilt as the machinist/crack tester missed a hole/crack in the block and i had oil weeping through, from one of oil drain galleries. Obviously not paying for anything, just inconvenienced as i am without my car again; especially when the build exceeded all my expectations/goals just on the run-in tune.

I am located in the Western suburbs, 5mins from Calder Park Rwy. Would be good to meet up once all our cars are running properly, unfortunately Matt had some issues over the weekend as well, so i couldn't drive his car.

Running a Extreme Turbo Manifold and the setup is currently internally gated. I have compared pictures of Kyle's manifolds with the ETM manifolds and they are very similar in design and quality. The only reason i went with ETM is that, at the time of order i never heard of 6boost and after i paid for the manifold, 6boost started getting a really good reputation on SAU. I agree with what Kyle has stated; that a really top quality, efficient, manifold will require better boost control at low boost settings. He is obviously trying to go out of his way to help you resolve the issue and sounds like a honest person.

[Roy]

Your set-up and Matt's (Yellow R33 GTST) setup are almost identical, except he is still using the 2.5ltr and you have a 3.0ltr, you both have a 6boost manifold and he even has the 90deg extension for the gate. Why isn't he having boost creep issues? The difference; he has a 0.8#a/r ext. housing on his GT3076R, you have the same ext housing on a bigger turbo that has a bigger ext. turbine. Is it starting to sink in now? Go to ATP, trade your ext. housing for a 1.0#a/r housing and your problems are solved, instead of spending twice as much on a 2nd WG or a bigger WG.

Just to sabve confusion, which there seems to be a bit of A 3076 and 35R do not run the same exhaust housing, do they? The GT30 series turbo runs a certain sized turbine. The GT35 series turbos run a larger turbine again.

So all being little math buzzards, A/R is only a ratio of cross sectional area in the scroll to the radius of the scroll at the point the area in measured. So whils the housing shatre the same ratio they are not the same housing. They cant be, the larger GT35 turbine is well , of a larger diameter. So that means for the housign to be mounted on it then its "R" measurement is larger to cater the bigger turbine. So to maintain the 0.86 ratio then the cross sectional area of the scroll at that point needs to be larger. So the housign is nto only different.

You wouldnt expect a 0.86 GT28 turbo off an SR20 to be the same as a 0.86 housign off a GT35 or T04Z turbo.

Im not sure the bigger housing on the GT35 will do the trick , its already bigger. Not to mention that that the outlet diam of the GT35 housing is probably bigger to allow for the larger turbine. The reason why a smaller exhaust housing on a big turbine often flows better then a larger housing on a smaller turbine

[Al]

Don't understand about 50% of what you just wrote Troy, read over it about 5-10 times and still no go, sorry.

As stated previously; speak to the people in the business (turbo dealers: ATP, GCG, etc) and discuss the issue. From my chats with my mechanic i still believe changing the ext. housing will solve the issue.

Just something i just thought of Troy. When a std turbo is hiflowed, they fit bigger wheels inside the std housings, so it just goes to reason that more than one wheel size can fit in a housing. I don't know too much about the engineering or a turbo, but that is why i have stated that Andru speak to a expert.

I do know that the same a/r rating do come in different sized housings, not sure if that is the case between the GT30 and the GT35 as they belong to the same "series/family" of turbos

[govich]

Don't understand about 50% of what you just wrote Troy, read over it about 5-10 times and still no go, sorry.

A grain of sand can be twice as big as another grain of sand or a planet can be twice as big as another planet, it's still twice as big. GT35 0.86A/R housing is bigger than GT30 0.86A/R housing..

[Al]

A grain of sand can be twice as big as another grain of sand or a planet can be twice as big as another planet, it's still twice as big. GT35 0.86A/R housing is bigger than GT30 0.86A/R housing..

Genius..........

Did you continue reading after the first line of my post before posting?

[govich]

Genius..........

Did you continue reading after the first line of my post before posting?

Nope.

My bad

[6BOOST]

A GT3071, 3076, 3082 and 3582 turbine housing are all identicle, the only difference is the size of the hole bored in them for the turbine wheel, which is bigger for the 3582, all the others have the same size exhaust wheel. You could take a 3071 .63 turbine housing, machine it out to GT35 size and slip it straight on, it would be identicle to buying a GT35 with one already on it.

Secondly to that, the smaller turbo explains boost control. Some people in this thread have said remove the exhaust. This is the worst thing you could do, more back pressure/more retriction will create lower boost, so leaving it on will giv eyou the lowest boost possible. Some of my customers street/race cars pick up 10-15 psi of boost when the drop their 3" exhaust at the track. The 3076 will be holding lower boost because it offers more retriction and back pressure hence more air will exit the gate.

I will reinterrate what I have said 2-3 times now Andrew, I have NUMEROUS RB30, 25/30 and 26/30 engines that have no boost control isues with a 44mm gate. I have at least 10:1 ratio of ones that have No issues to ones that do. You have an issue with the fact that I told you a 44mm gate should be fine, but what would you have me say?? If people are on a budget or doing things as cheap as possible, heck, even if they aren't, do I tell every customer to go and spend another $350 on a bigger gate over a 44 when 95% of people have no issue?? DO I just offer my advise to each person that it MAY work but they should consider a 60??

I empathise with your position, I have been thru this on a customers car myself before, we put 50/50 pump fuel and tolulene in and brought peak boost down from 27psi to 21psi, we then changed the intake manifold to something better and it came down even further again. Other than that, we now run the wastegate from the turbine housing where possible. I understand you feel its dodgy, I think the exact opposite, I'd PREFER to run it off the turbine, and do so on my own car, everyone of my friends cars, and any customer that will listen and let me do it. You have better boost control, more hp, faster spool, and I PERSONALLY don't think it looks dodgy. Each to their own. As I said earlie tho, if the gate isn't a restriction, why does it go up when you fit it back on the manifold?? Theoretically it should stay at 13psi when open. Hope you've removed one of those springs.....

6BOOST

[VB-]

kyle, dont take what i said the wrong way, (i'm andrews mate that spoke to you on the phone) i know it will work welding it to the housing, but the cars got a plazmaman plenum, rocker covers will be painted, compressor cover might be polished, and wiring may also be hidden later on, hes trying to go for a neat engine bay, and trying to keep shit hidden. hes seen a few bays where basically all you can see are the 3 main things, rocker covers, plenum, turbo and i think thats what hes aiming for.

hes also looking at upgrading to a TO4, yes even though the car isnt running properly, an upgrade is already on the cards, and it will be troublesome trying to sell the turbo with the provision for the gate hanging off it

lastly, i dont think its something that should have to happen, he should be able to control boost off the manifold, real question being how we are going to go about doing it

[6BOOST]

By sending me the manifold and paying the difference to a 60mm gate and letting me modify it to suit. It'll work, no question. I would however like to know if anyone has really pulled the second spring out of th egate, I'd really like a dyno graph to show it also, and if it doesn't go past 21-22si, I'd like to see it run to redline, or to whatever rpm it takes to hit 21-22psi. Its getting too hard to diagnose when I can't see fist hand whats going on, except that others, in large numbers have had no drama's, its gotta be fixable.

6BOOSt

[R34NRG]

finally the answer ive been searching for

we've finally been able to fix the issue and the car is holding boost =]

below is a dyno chart of our findings

the above shows a modified manifold with dual ports that lead to a 60mm port that leads to the gate.

one is with a 44mm gate, and the other with no gate.

so in conclusion, we had to increase the diamatre of the manifold and run a 60mm gate.

my only issue now is finding a 60mm gate.

so the search continues.

cheers to everyone especially 6boost and the certain few who knew wat they were talkn about.

look forward to when the car hits the road =]

Edited May 9, 2008 by R34NRG

[paulr33]

glad you got it sorted

10psi @ 4800rpm.... what the ?

[DRIFTER]

i thought kyle was going to do an exchange gate for you? if not you could get a chinese gate for around $200.

p.s. what are the drawn on lines on the graph?

[VB-]

that is a print out, nothing drawn as such, they were both the same colour n shit to ray changed the colour of the lines, one just looks chunky. low one is no gate, high one is 40mm gate with no spring

paulr33, one run is with no gate, the other is with no spring in the gate, hence its coming on song so late. the run with the gate but no spring was more to determine if it was big enough, thats why the spring(s?) were left out

edit - i believe kyle was going to do an exchange on gate + mod the manifold, but andrew just wanted to get the car done with as little hassle as possible, so ray modded the manifold, hoping to see it work with the 44mm, but gates too small, so now andrew will be upgrading gate

Edited May 10, 2008 by VB-

[paulr33]

ah yeah - good point

hence slow linear power curve, will be good to see it completed

[VB-]

yeah well it so damn close now, after like 7 months lol. just a question of what gate, and where its coming from now... its not my car and even im getting a lil anxious

[6BOOST]

Have sorted Andrew out with a new tial 60mm at cost and will be also refunding him money in return for his used gate as well, if he didn't get it today, should have it tomorrow. Look forward to seeing the final power firgure, we know its flowing some unrestricted air at least;)

6BOOST

[SirRacer]

Old post but im very glad you guys have sorted this problem. (ive read through the whole lot, and albeit painfull in some places is a very good thread).

Im having exactly the same issue here in NZ with a turbo manifold i had made by a local guy. By all accounts my setup is very similar to Andrews. The manifold builder has now made me another manifold which apparently (i havent driven it yet) holds boost in first and second yet once the car is in third looses the plot.

I was also looking to avoid having a gate stuck out the exhaust housing, however think now that it may be the easiest option.

6Boost (or anyone here), do you have a descent quality picture of a wastegate mounted off the turbo housing?

Edited February 28, 2009 by SirRacer