pro's & cons of an external wastegate? what are they
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pro's & cons of an external wastegate? what are they & what application are they best to be used?

SKYLINES ARE LIKE CLITS, EVERY FLANGE SEEMS TO HAVE ONE: see this sticker on my silvia

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Tom Fenton says: I have it all, make me an offer

integral wastgates are a compramise for OEM mass production turbo cars, cheap, mass produced, & ease of fitment (space)

you will never see a top turbo cup winner running a integral wastegate

so what would it take to run an external wastegate what would be the method, differant turbo, does anyone on here run an external, would there be benefits for me to have one & fit it now before the motor go's in or does it depend on boost level etc

Edited by clubminiflip on 10th Feb, 2007.

SKYLINES ARE LIKE CLITS, EVERY FLANGE SEEMS TO HAVE ONE: see this sticker on my silvia

the Search-section on this forum is blummin superb & simple to use, unlike some other forums, without the search-section & the help of this bunch of chaps on here i'll never be able to !!!Start the day with a 998cc turbo!!! :) i'm getting closer though!

Tom Fenton says: I have it all, make me an offer

Run one, if you need one.

I've yet to see anyone come in the top 3 at Avon, mini shootouts, anything... who run an external 'gate.

Don't go out of your way to fit one to a stock metro turbo, or even a 'modded' setup. You'll unlikely see a difference; especially on the large (for a 1300 engine) poppet valve on the T3's.
Your money is best spent elswewhere - unless you've already done everything else.

Edited by turbodave16v on 10th Feb, 2007.

I agree with Dave.

If you are approaching the point where an internal gate cannot flow enough to hold a solid boost level then (assuming an internal gate upgrade has been tried) it's probably worth moving to an external gate.

This brings added complication to the manifold design and depending if you vent it to atmo, you will need to consider the extra noise if you are track day enthusiast.

The more boost you desire to run, for a given setup, the less exhaust gas needs to exit via a wastegate so it's not a simple as a 30psi monster needs an external gate..

There is no extra noise with an external wastegate if you plumb it back into the exhaust. Infact there is a schhol of thought that suggests that putting the external wastegate back into the exhaust can have positive effects.

As mentioned above though it is unlikely you will need one unless the turbo you have does not have an internal wastegate.

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so there is'nt any real distinct advantages for small turbo applications like mini/metro turbos, renault 5's, charade gtti's etc unless you make a specific install using a turbo with no internal wastegate, i presume if you wanted to use on for any reason you'd just tack weld the internal gate shut,

so the external wastegate, was that the earlier form used on turbo applications of any sort untill the development of the internal

Edited by clubminiflip on 10th Feb, 2007.

SKYLINES ARE LIKE CLITS, EVERY FLANGE SEEMS TO HAVE ONE: see this sticker on my silvia

the Search-section on this forum is blummin superb & simple to use, unlike some other forums, without the search-section & the help of this bunch of chaps on here i'll never be able to !!!Start the day with a 998cc turbo!!! :) i'm getting closer though!

Tom Fenton says: I have it all, make me an offer

I'm not sure I'd tack weld the internal gate shut and trust it to stay that way.

Far safer to run a solid mount on the end of the actuator bar instead of an actuator!

Every day is a school day ...........

How fast and how expensive ...... the same question...

Most use the standard internal wastegate hole and weld an external wastegate flange to it ( exiting through the exhaust outlet plate) and join it back into the exducer outlet pipe atleast 18" away..

bit of a resurrection. i have a few turbos to choose from on my new build. and they all have the same exhaust flange but some have no wastegate and some have an internal one. i wanted to fit the bigger of my turbos (the one with no wastegate).

My question is this. with there being no internal wastegate at all. im assuming it will flow better around the turbine side. and that an external one (running 1bar of boost+) will be better for the overall setup/performance compared to internal?

It will be plumbed into the exhaust not to atmos if i choose to use this turbo.

That being said. i have no experience with external wastegates. what sort of size should i be going for?

Thank you.

As it's a Mini, you certainly wouldnt need a large wastegate. I'd say 38mm at most.

Although not even sure if there are many options smaller than that. Generally below 4-500bhp there really isnt any need for an external gate.
Internal's below that are all designed to have adequate flow for the particular turbo.

Although other than packaging, I'd hardly say there are any negatives to using one.

Edited by stevieturbo on 11th Oct, 2012.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Edited by Brett on 14th Oct, 2012.

Yes i moved to the darkside

Instagram @jdm_brett

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

creepy boost; you can tell halloween is just round the corner :)

Steve, you have mis read, or just jumped to conclusions

The standard Wastegate of the gt20 is 14mm, It would hold a bar fne upto 4500rpm, then the boost just went off the scale.

Enlarging the Wastegate to 22mm, meant it held boost perfectly fine upto 6500rpm, and beyond.

Edited by bennyy on 12th Oct, 2012.

Audi s4 b5 - 470bhp & 486ft lbs

On 30th Apr, 2012 Brett said:
yeah stick the bit in and give it a wobble

Im in the proccess of fitting a 38mm wastegate as my gt20 one is tiny.

The main problem on a mini is space

13.95 1/4 mile on a 2.95 fd. Carnt be that hard to beat!

i have an external gate on mine; personally (and this is me personally) i found it easier by having an external gate and also space down the back than making an actuator bracket.

As eden says space is an issue but after my mk1 screamer pipe i know how i'm going to do a mk2. its all learning.

as to benefits.... prob none really on a mini unless you get a poorly designed internal gate or running uber boost

Sorry to jump in and ask - can someone give me a rough example of how an external gate in plumbed in?

My tiny morning brain can't work it out. Is it taken off the inlet manifold? and does it open at a specified pressure like an actuator run one?

Still fairly new to the turbo stuff, and enjoying the learning curve.

:)

http://www.tialmedia.com/documents/w3_tial_wginstall.pdf

in short it sits between the head and the turbo (exhaust side), with the top of the WG joined to the compressor hosing of the turbo like an actuator.

Edited by t@z on 12th Oct, 2012.

Thanks Taz

I think its a thing of, is it needed? My t3 and gt17 wasent needed but now ive got my gt20 I defantly feel the boost will be more controlable.

As far as im aware its on taz whos running one and mine in production atm?

13.95 1/4 mile on a 2.95 fd. Carnt be that hard to beat!

Iirc jimbo runs one on the twink turbo as well, i like the look of the external wg not sure it wouldngive much on the benifits wise apart from maybe being able to fit a small ball bearing turbo with no wg?

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9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

thanks guys, its just that i have a selection of turbos and the one i have worked out is probably the best for spool time and flow is the one without an actuator.

yeah i also thought 38mm would be too much. so ill go for one around the 22mm mark. and i have no worries for space as its 7port and the turbo is mounted quite high up and under it will be a mass of space. plus im having an internal pedal box and moving the wiper motor inside etc. so nothing in the way.

this is a manifold i made. not finished and i probably wont use it. because that turbo is not the one i am using. its a bit small.

http://i185.photobucket.com/albums/x28/joh...ld/IMG_0604.jpg

38 would be large, that's not to say it wont work though.

Ive seen people use oversized w/g's on their cars and they have seemed to work well. Although I wouldnt want to use one much larger than was actually needed.

I dont think Ive ever seen an external w/g smaller than 35mm though.

As for actual fitment, it doesnt have to be mounted directly to the manifold or even close to it. You can mount them quite far away if you had to. Only thing to consider, is try and make the flow path to the gate sensible. ie no silly right angles or reverse flow for gasses to get into it.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will