School me on wastegates... (1 Viewer)

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HI folks,

I am pulling together the items for a turbo on my 84 BJ60. I have found an interesting custom manifold for the 3B with a Garrett T3 flange. The seller (mud member) is also offering a brand new T3 to with it...

I am new to turbos and learning as i go here... The available T3 does not have a wastegate fitted right now. The seller says that it will work correctly without a wastegate fitted? From what I have read on here, adjusting a wastegate seems almost necessary to attain safe EGT's and long engine life... My engine has enough kms on it that I wish to keep the boost down in the interest of engine life and low-end power. I would like a quick spooling turbo which offers low-end grunt, i rarely rev my truck over 2500 rpm as it seems somewhat pointless...

So how do wastegates work and do I need one on at T3? I have asked for the exact model number and he belives a/r are both .48...

Thanks
 
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brampton ont
The waste gate act as a spring so when the exhaust gas reaches a certain pressure the waste gate opens.
Also waste gates can be boost operated ie when the turbo boost hits say 10 psi it opens up the waste gate pneumaticaly (by air pressure)

thoes are the two I know of
as for your turbo situation from what Ive read iIde go with one with smaller a/r numbers .42 I beleve Quick spool in low rpms but restrictive at highway speeds I have the .48 A/R

ps I run a ct26 (supra) no waste gate and hit upwards 15+ psi I feel its good for my application HWY driving and I dont worry aboot reving big blue out to 3000-3300rpm
 

RufusTheDufus

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A waste gate is a valve that allows some of the exhaust gases to bypass the turbo. In theory, a properly sized turbo doesn't need a wastegate. In practice, production turbo systems are typically designed to spool up quickly and starting producing boost at relatively low RPMs. In order to do so the turbocharger exhaust turbine is more restrictive. As exhaust flow increases the turbine spins faster and faster producing more boost pressure in the intake system. Too much boost or turbo spinning too fast can be problems.

A wastegate is typically set up to start opening a bypass valve to route some of the exhaust flow away from the turbo at a particular intake manifold pressure. It regulates boost pressure and the speed of the turbo's shaft. (These things spin upwards of 100k RPM!)

It's hard to say if you need a wastegate for a T3. There are lots of different configurations of T3s. We would need to know about the specs of your T3 to offer a better opinion, more specifically any identifying numbers like A/R .38, .42, .48, .63, etc. These would be on the exhaust side of the turbo.
 

RufusTheDufus

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I guess I should have added that I have a turbo on my 3B but no wastegate. Mine is an IHI RHB6, not a T3.

Ask the seller if it's a real Garrett T3 or if it's one of the Chinese copies flooding the market. The seller should be able to give you complete specs for the turbo.
 
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I guess I should have added that I have a turbo on my 3B but no wastegate. Mine is an IHI RHB6, not a T3.

Ask the seller if it's a real Garrett T3 or if it's one of the Chinese copies flooding the market. The seller should be able to give you complete specs for the turbo.
I believe it's a real one... at least he's charging me for a real one! In the photos I can see the Garrett box, however I can't make out any model #s specs.... The seller is going to provide that info today...

Thanks for the info guys, helps when I am trying to match things correctly... the seller said he has put a couple of these on 3Bs and they work good with no wastegate... however I don't want to get stuck with something that's not appropriate... If I run a boost guage can I keep boost max down by not overrevving the engine and watching my EGT's? I noticed without a wastegate there is a nice amount of clearance to the firewall, the downpipe would be a lot closer if an external wastegate was added I believe...

I have a pic or two of the turbo but don't have a star yet so can't post.... The output of the turbo is round about 3" and would be easy to make a downpipe although I don't quite understand how it attaches to the turbo output (the seller says some kind of clamp)

Will post the specs when i get them...

Thanks for the help guys....
 

RufusTheDufus

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A BOV will help limit boost pressure but it won't slow the turbo shaft down to a reasonable speed. BOVs are a good boost surge protection device but I don't think they are a good general purpose boost control mechanism.
 
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There is no T3 turbo in Garretts current aftermarket lineup. They do still make parts and cores for them though and a complete replacement turbos for OEM applications may still be available.

If you want a fast spooling turbo then you need a wastegate. A bigger turbo may not need one if the engine can't produce enough exhaust to create too much boost.
 
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If you are new to turbos you need to get a copy of "Maximum Boost" by Corky Bell. It'll describe all the options to you.

Personally, I think a wastegate is important. I run one on all my turbos and when it jams the boost can hit 15psi or more. Normally I run 8-9psi in order to gain maximum engine life.
 
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There is no T3 turbo in Garretts current aftermarket lineup. They do still make parts and cores for them though and a complete replacement turbos for OEM applications may still be available.

If you want a fast spooling turbo then you need a wastegate. A bigger turbo may not need one if the engine can't produce enough exhaust to create too much boost.
Thanks guys... the guy also has a IHI turbo, new as well with a T3 style flange... It has a wastegate preset at 8 psi... I was thinking this might be the way to go but I am still waiting on the a/r specs... will know in a couple of days.... The IHI is oil only, the Garrett is oil and water...
 
Joined
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Messages
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Location
Norfolk County, ON
Thanks guys... the guy also has a IHI turbo, new as well with a T3 style flange... It has a wastegate preset at 8 psi... I was thinking this might be the way to go but I am still waiting on the a/r specs... will know in a couple of days.... The IHI is oil only, the Garrett is oil and water...
Both of these turbos are factory off of diesel industrial motors, for what its worth.... so is the manifold for that matter... CNC machined to fit a 3B....
 

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