Remedying my boost creep. Advice please.

[JAAASH]

As some of you may be aware I've recently had my car mapped. Results were good but there's still room for improvement.

Unfortunately, I now seem to be suffering quite a lot of boost creep. Most noticeably in 4th and 5th gear, I've seen the gauge hit 24-25psi, at which point, the ecu says no more and cuts ign to save the engine.

So I've come to the conclusion that my internal wastegate just isn't efficient enough.
The turbo is a Garrett GT2871R (unsure of turbine housing A/R).

I want to convert to external wastegate in order to fix the creeping, so I've been doing a fair bit of searching, on here and google, etc.

It seems there's a few options available;

1. Custom manifold with built in ewg port.
2. Drill a hole in my existing manifold and weld on a flange.
Something like this


3. An adaptor that fits between the manifold and turbo with an ewg flange welded to it.
Then just disconnect or weld up iwg (seems to be lots of debate around whether just disconnecting will keep the flapper shut).

4. Swap my exhaust housing for the ATP special turbine housing. Seen here - http://www.atpturbo.com/mm5/merchant.mv ... y_Code=HSG


Now im not exactly a wealth of knowledge when it comes to turbos so i'm hoping somebody can step in and tell me that this will just be a simple swap of housings. Im unsure of the A/R of my current housing and this special housing is .72 A/R. Does that matter? I know it'll affect spool time, I just want to make sure I don't need to change anything else.

Another issue I see with this is that it will bring the wastegate out, facing down and possibly hitting the block.
I've found this 90 degree pipe that looks like it might work if that were an issue though.
http://www.himni-racing.com/wastegates/ ... -stainless

Number 4 is probably my preferred choice, due to the cleanliness of it. Obviously a custom manifold would be nice but then we're talking major £££ and it's probably a bit overkill for my setup.

Looking at using a Tial MVR wastegate like this - http://www.tialsport.com/index.php/tial ... tes/39-mvr

Any help appreciated,
Josh

[mr2magic]

Is the IWG standard on that garrett exhaust housing?

[JAAASH]

Ye, standard Garrett 7-8(?) psi IWG. Tested and working perfectly. Just not efficient enough.
Boost is being controlled by the ecu via a solenoid. We've got control up to 1.2bar but then it starts to creep.

[C35Rob]

If it were my car, I'd get one of the turbine housings with the wastegate flange on it, probably the cheapest method too unless you can do the welding yourself

Are you using a seperately boost controller or the ECU to control boost?

[JAAASH]

As long as that housing is just a bolt on affair then that's what I'll be doing. Just wanted someone to confirm it for me.
As well as opinions on the clearance for the wastegate to actually bolt to it without fouling on the block.

ECU is controlling boost.

[shinny]

As long as that housing is just a bolt on affair then that's what I'll be doing. Just wanted someone to confirm it for me.
As well as opinions on the clearance for the wastegate to actually bolt to it without fouling on the block.

I was looking at the special housing too... and I couldn't convince myself there's enough space between the turbo and the block to get a 44mm wastegate in there. Perhaps there is enough space for 44mm pipework to position the wastegate further away. It's probably your best bolt-on solution, though, if it fits.

[JAAASH]

if it fits.

That's my worry. If it will definitely bolt on to my turbo then I think I'll try it. I'll get that 90 degree pipe with the v-band fittings that I linked to in the first post and see how it goes.

[shinny]

if it fits.

That's my worry. If it will definitely bolt on to my turbo then I think I'll try it. I'll get that 90 degree pipe with the v-band fittings that I linked to in the first post and see how it goes.

Clearly I didn't properly read your first post as you had all the same thoughts i did. Do let us know how the plan works out... I'd be interested to here

[jimGTS]

Bore out the current wastegate???

[2mad]

Bore out the current wastegate???

Well worth a go

[shinny]

Bore out the current wastegate???

Well worth a go

Repeatedly taking the turbo off and on is a bit of a PITA... personally I'd go for a solution that's get a better chance of working. Porting the wastegate can work, but isn't guaranteed by any stretch of the imagination. I guess it depends how much you value risk of having to do it all again vs the cost of going straight to parts that will certainly do the trick...

[2mad]

I've ported a ct26 and a ct20b with great success .. cant vouch for a gt turbo so shinnys absolutely right .. depending on how much materiel you can remove it might not be enough or could be spot on .. its one of those suck it n see jobs , wont know till you try


What would i do .. i would port it .. if that didnt work i would have the turbo identified and buy a new exhaust housing , adapter with external wategate fitting and wastegate ... enjoying some screamer pipe action .


Just my 2p...


Best of luck,

Kev.

[Kongaroo]

If you are creeping to 24/25 psi you may struggle to control that even with an external wastegate.

I had boost creep to around 20+psi with the GT2860rs even with a Tial 38mm external wastegate on my previous car. Although that turbo is a slightly better spooler than the GT2871r so your plan to fit an EWG may still work.

For myself I found the only way I could get the boost creep on my car under control was by restricting the exhaust to a smaller diameter to reduce exhaust gas flow.

However restricting exhaust flow went against the grain so in the end I decided to run a higher volume of methanol injection to increase my fuel octane so I could turn the boost controller up past the boost creep point relatively safely. That worked very well but I was always super paranoid about the methanol kit failing

[JAAASH]

I had considered porting the current wastegate, but the more I read into wastegates, the more I was sold on converting it to external. Much more controllable boost, less turbulence within the exhaust housing, etc, etc. it just seems like the right thing to do.

[2mad]

I had considered porting the current wastegate, but the more I read into wastegates, the more I was sold on converting it to external. Much more controllable boost, less turbulence within the exhaust housing, etc, etc. it just seems like the right thing to do.

If you have the money I totally agree .. i was just offering a cheap (passably free ) option

[JAAASH]

I almost bought an exhaust restrictor the other day but after a conversation with 'he who shall not be named', he said that it would have little effect and that external wastegate would be my best option. Which is why I started doing some research into them.
I've also got methanol injection set up, although not being used at the moment. Plan was to introduce it after 1.2 bar once we can control boost. I've also bought a failsafe kit for it so whenever the flow falls out of a given range, due to a failure of some sort then it will signal the ecu to cut boost straight away.

[shinny]

When I had lots of boost creep on my old CT20Bs, Voldemort was suggesting restrictor rings to me; I tried them and found they had little effect on boost creep but did feel like they strangled the engine. I went for a 38mm gate in that case and it works a treat (until I got my local JDM "specialist" to make me a manifold)

Now I'm on a GT2860RS and still had boost with a 38mm wastegate (albeit poorly positioned). I've solved it by going twin-wastegate (both internal and external running together) which is working well enough. I'm sure a single 44mm gate would be a better solution though.

[Kongaroo]

I had a single exit 4" exhaust at the time and the way I experimented this was by having 2 different diameter exhaust bungs made up by Hayward and Scott to reduce the exhaust exit diameter. But similar in theory I guess to the restrictor plate.

On my car it had a marked effect on the boost achieved/boost creep but I agree with Shinny that it felt like it was strangling the engine so that mod didn't stay long. It did reduce exhaust noise a little though which was one bonus

[JAAASH]

When I had lots of boost creep on my old CT20Bs, Voldemort was suggesting restrictor rings to me; I tried them and found they had little effect on boost creep but did feel like they strangled the engine. I went for a 38mm gate in that case and it works a treat (until I got my local JDM "specialist" to make me a manifold)

Now I'm on a GT2860RS and still had boost with a 38mm wastegate (albeit poorly positioned). I've solved it by going twin-wastegate (both internal and external running together) which is working well enough. I'm sure a single 44mm gate would be a better solution though.

Voldemort As soon as I mentioned GT28 he said the restrictors would be no good.

I read that you were running a twin-wastegate setup so I went and found your thread on mr2oc and spent a couple of hours trawling through it to find some info. There's a GT4 WRC manifold on ebay at the moment that I considered doing the 4 into 1 wastegate setup with, until I found the ATP special turbine housing.

[JAAASH]

I had a single exit 4" exhaust at the time and the way I experimented this was by having 2 different diameter exhaust bungs made up by Hayward and Scott to reduce the exhaust exit diameter. But similar in theory I guess to the restrictor plate.

On my car it had a marked effect on the boost achieved/boost creep but I agree with Shinny that it felt like it was strangling the engine so that mod didn't stay long. It did reduce exhaust noise a little though which was one bonus

I do have an exhaust bung somewhere actually. I may try it, just as a temporary measure.
On the subject of noise (I'm using a KO Racing R1 single exit), I am thinking of having a high flow cat welded into the downpipe to try and quieten it down a bit, but im worried about it affecting the readings to my wideband sensor Thats a project for another day though. I can live with noise, I cant live with boost creep