Blanking off the dump valve?

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BALDYMONSTER
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Blanking off the dump valve?

Post by BALDYMONSTER »

I’ve looked online but can’t find a blanking plate to do this anywhere.

The reason being is that it feels like the car is leaking some boost and it’s stuttering ever so slightly on occasion. I’ve checked for boost leaks as much as possible but can’t find anything but after turning the Sard BOV to increase pressure on the spring it does seem to be slightly better but there’s something still not right. I’m not getting that thump in the back, and strong smooth surge of boost through the rev range and under acceleration I did with the original turbo.

Is there a common way to blank this off?

I’d just like to eliminate the BOV before I go any further.

Or perhaps does anyone have an original recirc valve they’d be willing to sell?


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Re: Blanking off the dump valve?

Post by SonicSW20 »

TB Developments sell a blanking plate.

Have you pressure tested and/or smoke the charge piping to check for leaks?
Are you measuring boost pressure accurately, and if so is it reaching the same level of pressure and holding it?
Is the turbo exactly the same spec as it was before as you've recently changed it and are referring to an original turbo?
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Re: Blanking off the dump valve?

Post by BALDYMONSTER »

SonicSW20 wrote: 07/10/20 19:14 TB Developments sell a blanking plate.

Have you pressure tested and/or smoke the charge piping to check for leaks?
Are you measuring boost pressure accurately, and if so is it reaching the same level of pressure and holding it?
Is the turbo exactly the same spec as it was before as you've recently changed it and are referring to an original turbo?
No pressure or smoke test no.

Boost pressure seems to be accurate as I have a blitz EBC and an omori gauge both in psi. Peak boost can deviate a tiny bit by . of a psi on the Blitz EBC display but I’m presuming you’d expect that?

The new turbo is from GT4 Heaven:

“TOYOTA CELICA ST205 GT4 94-99 2.0 3SGTE CT20B TURBOCHARGER 17201-74080 REBUILD”.

12 month warranty.

It’s "censored" me off tbh as it just isn’t boosting how it should, it doesn’t feel as punchy and like I say it just feels like it’s got a leak somewhere.

Obviously a steel not a ceramic shaft.
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Re: Blanking off the dump valve?

Post by BALDYMONSTER »

Spoke to a local tuner today about checking for boost leaks, which he can do. Pressure and smoke test.

But he reckons there isn’t much point as the car will “need remapped to the new turbo, and that’s most likely the issue”.

Now given it’s just a refurbed CT20B and I’m aware a few things might be slightly different. Steel shaft instead of ceramic, possibly different blades.

Would this really require a remap? Is there not enough “movement” in the standard ecu to deal with a refurbished unit?

It’s not that bad, like I said it just feels like something isn’t quite right. And I know to get the best out of any setup a full remap is the way to go but considering what I’m running I struggle to believe I now need to buy a stand-alone ecu and pay for a day getting it all mapped and setup just because I’ve fitted a refurbed turbo?
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Re: Blanking off the dump valve?

Post by SonicSW20 »

Tuner would say that, I'm sure they would be delighted to sell you an ECU and mapping session.

The stock ECU is versatile enough to handle pretty much any CT based turbo you put on it. The stock ECU will even cope with a small frame turbo like a GTX2867, but you'd not be getting your moneys worth from it.
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Re: Blanking off the dump valve?

Post by benckj »

ECU map is not your problem. I’d personally build a simple kit to block off TB and apply 15psi to induction pipes to see where leak is. You will be surprised at clamped hose fittings leakage.

Another common source of boost leak is the ISCV under TB. This valve often sticks and allows pressure to bleed back to intake. Easy check is to block this hose off to see if your boost holds better.
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Re: Blanking off the dump valve?

Post by BALDYMONSTER »

SonicSW20 wrote: 08/10/20 18:09 Tuner would say that, I'm sure they would be delighted to sell you an ECU and mapping session.

The stock ECU is versatile enough to handle pretty much any CT based turbo you put on it. The stock ECU will even cope with a small frame turbo like a GTX2867, but you'd not be getting your moneys worth from it.

I thought as much.

Talking bollocks.
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Re: Blanking off the dump valve?

Post by BALDYMONSTER »

benckj wrote: 08/10/20 18:35 ECU map is not your problem. I’d personally build a simple kit to block off TB and apply 15psi to induction pipes to see where leak is. You will be surprised at clamped hose fittings leakage.

Another common source of boost leak is the ISCV under TB. This valve often sticks and allows pressure to bleed back to intake. Easy check is to block this hose off to see if your boost holds better.
Same tuner can do a leak test for £70 but he “doesn’t want to waste my time or money”.....mmmmmmhhhhh, right then.

It’s in getting a couple of spots of surface rust seen to so when I pick it up again tomorrow I’ll tell my guy to have a look when it’s getting it’s inner driveshaft seal replaced.
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Re: Blanking off the dump valve?

Post by BALDYMONSTER »

Checked and tightened up all the hoses today, also disconnected the Blitz EBC and just ran a hose from turbo to wastegate.

Boost feels better as far as building up and consistency is concerned but it will only make 10 psi and still feels too laggy but that could be just me to be fair. Note it’s a revision 3 turbo not a 1 or 2.

Ive got a Dawes device coming on Monday but I’m thinking this is possibly a weak wastegate?
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Re: Blanking off the dump valve?

Post by SonicSW20 »

10psi on stock wastegate actuator is correct. If you're direct from turbo to actuator and it's holding around 10psi, your actuator is fine.
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Re: Blanking off the dump valve?

Post by BALDYMONSTER »

SonicSW20 wrote: 10/10/20 18:57 10psi on stock wastegate actuator is correct. If you're direct from turbo to actuator and it's holding around 10psi, your actuator is fine.

I thought the rev 3 engine was supposed to boost to circa 12-13 psi on the standard ECU?
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Re: Blanking off the dump valve?

Post by BALDYMONSTER »

SonicSW20, you have PM buddy.
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Re: Blanking off the dump valve?

Post by benckj »

BALDYMONSTER wrote: 10/10/20 21:01
SonicSW20 wrote: 10/10/20 18:57 10psi on stock wastegate actuator is correct. If you're direct from turbo to actuator and it's holding around 10psi, your actuator is fine.

I thought the rev 3 engine was supposed to boost to circa 12-13 psi on the standard ECU?
That is correct if the stock TVS boost controller is operational. If only running WG pressure as he is then the boost is controlled by actuator spring tension which is about 7 for a rev1 and 10psi for rev3.

Generally the spring pressure won’t change but might be worth increasing the preload tension if a boost leak suspected. Can do this by adding washers to actuator mount.
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Re: Blanking off the dump valve?

Post by BALDYMONSTER »

benckj wrote: 11/10/20 18:19
BALDYMONSTER wrote: 10/10/20 21:01
SonicSW20 wrote: 10/10/20 18:57 10psi on stock wastegate actuator is correct. If you're direct from turbo to actuator and it's holding around 10psi, your actuator is fine.

I thought the rev 3 engine was supposed to boost to circa 12-13 psi on the standard ECU?
That is correct if the stock TVS boost controller is operational. If only running WG pressure as he is then the boost is controlled by actuator spring tension which is about 7 for a rev1 and 10psi for rev3.

Generally the spring pressure won’t change but might be worth increasing the preload tension if a boost leak suspected. Can do this by adding washers to actuator mount.
I’ve got a Dawes device coming tomorrow to bypass the Blitz EBC so I’ll see how it boosts and runs once that is fitted. Rule out the EBC.
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