GT2871 boost creep??

[stevecrc]

what is the cost of a exhaust housing? would be worth cosidering

[immy21]

Just reading a debate on a US site about cast manifolds and dividers, very interesting.

Got a link?

[stevecrc]

sorry mate I have lost it

[immy21]

[stevecrc]

lol after I finished reading it I closed the page down, I found it as it was a link on something else I was reading and cant find that either

[M.D.]

Easy to weld a flange into the HD manifold too. Just weld a plate in the tube to keep it divided right up to the waste gate port. That way you avoid the gasses doing funy things at the waste gate outlet.

If you need to use a 90' bend then just cut it in half length ways. Set one half down on a sheet of 2.5mm or so steel ad draw round the profile. Then you can cut this banana shape out. And weld the tube halfs either side of it and you have a divided 90' elbow. .

[skidder166]

hi Guys,

Thanks for the info. I was just planning on buying a 2871r with .64 exhaust housing. I was about to purchase a HDEV manifold. what would be the best way yet still reasonably affordable way to go external wastegate? Still not sure if it requires to go top mount?

I've got an AVCR so hoping this will help but is there is a fundamental problem with wastegate size then I cant see this fixing it!

[justbutts]

Mine used to boost creep, i spoke to turbo dynamics and they say the turbos they supply to apt have all been ported but didnt specify what size to. they done mine for mewhich improved it vastly have have also found that one of my high flow turbo elbows also increased the creep problem. i fitted my old stock elbow back to the car and i got constant boost at all levels that i set the boost to.

[big_mac]

that is masking the problem tho, exhaust backpressure does help prevent creep. Having backpressure looses you power, slows spool, reduces response and you also hve to run higher boost to achive the power levels you currently run.

you may have found that lowering the boost level with the free flow elbow would have prevented the creep and resulted in much the same power.

[Gary@APT]

lowering boost will show creep even more

we get it lots with evos running the bigger 9 turbo they will creep to 1.2 bar when cams start to work 5k and above

raising boost above this threshold then gives a flat boost plot

its ok on a evo as it can hold big boost,what we found with gt2871's on 200's was using a .86 housing the engine didnt produce enough gas's to drive turbo and changing back to .63 gave power but also creep
we did have wastegate ported by turbo dynamics but also did more internal to get boost low enough for stock engines

[big_mac]

so its more a problem with the wastegate on the .63 housings then?

[M.D.]

so its more a problem with the wastegate on the .63 housings then?

You will prob find the gates are the same size on both housings. But as it takes less gas volume to spin the turbo with a smaller housing you need to get rid of more gas to hold the boost down. So it should come with a larger port but doesn't.

[Gary@APT]

spot on saved me a reply

[stevecrc]

Well I have now fixed my boost creep issue in the form of a 38mm tial external wastegate. I had to modify my H/Dev manifold but was pretty strait forward in the end and wow it has mad such a difference not only in the fact that there is no more boost creep but is so much more responsive and feels much stronger.
Took a few pics for you all lol



excuse the cable tie I was waiting for some stainless one's to be delivered lol




Just need to get it back to have the mapping finished and boost controller set up but I am well happy with the results

[chapman-s13]

Rude....

[M.D.]

This is the exact sort of thing I like.
Nicely done.

Now place your bets as to how long you will last with a screamer. I bet you will be plumbing it in within a fortnight lol

[clive]

Very nice


Although Surely you wanna brace it..

[stevecrc]

I have clive, If you look carefully the is a brace between the wastegate pipe and the manifold

[JC SX]

I'm running gt2871 .64 housing and at stock actuator boost so 7-8psi I have the avc-r set to off so it just monitors the boost level
I find it's not crept to more than 8psi and it is pulling like my car did at stage1a with standard t28 at 17psi
It also never puts the injectors over 92% so I'm happy there to drive it
I wonder if having a 3inch elbow 3 inch straight through system with no cat or back pressure is why I'm not getting creep, according to above I should be struggling to keep it from creeping as I want it at lower boost

[stevecrc]

I'm running gt2871 .64 housing and at stock actuator boost so 7-8psi I have the avc-r set to off so it just monitors the boost level
I find it's not crept to more than 8psi and it is pulling like my car did at stage1a with standard t28 at 17psi
It also never puts the injectors over 92% so I'm happy there to drive it
I wonder if having a 3inch elbow 3 inch straight through system with no cat or back pressure is why I'm not getting creep, according to above I should be struggling to keep it from creeping as I want it at lower boost

Its very hit and mis as some will do it and some wont and some only do it a little, for some odd reason mine was really bad lol.

As for exhausts, the more restrictive the more it is less likely to creep as it induces back pressure in the turbine housing helping to reduce creep, so a full 3" system is more likely to do it than a 2.5". mine is 3" from turbo back and as strait as your ever going to get an exhaust lol.

Even my mapper cant get over how bad mine was creeping! funny thing is he mapped another 200 with almost the same spec as mine and that run 10psi on actuator pressure without any probs.

One thing I have noticed is that dam its so much quicker and responsive at the same boost with an external gate pretty shocked at the difference its made.