Why wastegate a stock turbo, or 38R...

[Big Bore]

Frank, you are not at high altitude. High altitude is 5 to 6 thousand feet. You are at extreme altitude. It is a wonder you can even get enough oxygen to bust off a motor up there.

I really want to come up and visit though, you have some awesome views.

I gain about 2psi down in Denver. I gain another 2-3psi going down to Austin. So about 5psi gain from here to sea level. Assuming the guy hitting 38-40 psi is at sea level or thereabouts, I'm still lacking about 5psi?

Maybe you're right and I'm being picky. I know the truck ran like a raped ape down there.

You're welcome any time, give me a holler if you're headed this way.

 

[V-Ref]

Exactly... Drive pressure is what kills the stock turbo, even the 38r...

At 25psi the stock turbo with the wastegate disconnected will see 50-52psi back pressure. That is A LOT of side loading on a turbo.

I agree with the post above.

Oil starvation/supply issues (usually during initial install), high lateral side loading of internal bearing assemblies caused by high drive/boost PRs, and excessive turbo rpm are what Elite fellas told me are the most prevalent turbo killers, especially on diesel applications.

I'm hoping to spring for the Garrett turbo speed sensor package in the future.....I'd like to think the ability to plot a PR/wheel rpm on a compressor map, and analyze the drive pressures in either a single or compounded setup would allow for a true "tune" of your setup, and allow for longevity at the same time.

 

[JAP]

Mine was most noticeable at interstate speeds. With my wastegate actuator hooked up to my back pressure line, I was able to maintain speed with minimum throttle. It lacked a lot in spooling and around-town, but man, it was awesome on long stretches. I didn't do it long enough to get any MPG numbers, but I'd be willing to bet it was at least 1 mpg better.

 

[Hotrodtractor]

add?????

Yes. As in the built in one is not adequate enough - if it was we wouldn't be talking about 25psi of boost with 50psi of back pressure.

 

[David N]

Well how do you adjust the wastegate on a 38R? Like I said, mine only makes alittle over 30psi with it plugged in.

 

[CurtisF]

Frank, IIRC your 38R has a ported compressor housing (same as mine).... right?

I've always wondered if a bit of boost was sacrificed by going with the ported housing in order to prevent the surge issues that are sometimes seen on these turbos.

 

[Big Bore]

Yes. As in the built in one is not adequate enough - if it was we wouldn't be talking about 25psi of boost with 50psi of back pressure.

I guess I should get a backpressure gauge on now so I can see what the 38r is doing before adding an atmo.

 

[Tom S]

Frank, IIRC your 38R has a ported compressor housing (same as mine).... right?

I've always wondered if a bit of boost was sacrificed by going with the ported housing in order to prevent the surge issues that are sometimes seen on these turbos.

Does anyone even do port on these anymore?

 

[Big Bore]

Frank, IIRC your 38R has a ported compressor housing (same as mine).... right?

I've always wondered if a bit of boost was sacrificed by going with the ported housing in order to prevent the surge issues that are sometimes seen on these turbos.

Yea housing is ported. But I think you always saw more boost than I with your stock injectors. Do you remember what those numbers were?

Tom I thought the stock housing on the 38r was ported now?

 

[Tom S]

Yea housing is ported. But I think you always saw more boost than I with your stock injectors. Do you remember what those numbers were?

Tom I thought the stock housing on the 38r was ported now?

I do not think they are but you may well be correct. Anyone know for sure?

 

[CSIPSD]

The 38R has always had a ported compressor housing. Bob used to do some added porting for people who had surge issues at the higher boost levels.

I doubt it would be an issue now after Garrett retooled the 38R a few years ago.

 

[Tom S]

Ok, what defines a ported compressor housing then. I think maybe that is where we are not on track.

 

[Dmstrucks02]

Maybe I should loosen my gate up a little, I can see 32psi boost if I lay into it with stock injectors

 

[dietoremain]

Most i've ever seen on my stock is 26 or so with the red line unplugged(PHP tunes, and thats the gauge T'd into the map line).

 

[TrailerHauler]

Good read!

Does anyone have any other gate besides the stock wastegate on their 38r or factory charger?

 

[Hotrodtractor]

Good read!

Does anyone have any other gate besides the stock wastegate on their 38r or factory charger?

Yep - its been done before. In fact BDP dynoed a truck not too long ago with a 38R and an additional gate and it made some pretty good numbers.

 

[CSIPSD]

Ok, what defines a ported compressor housing then. I think maybe that is where we are not on track.

ATS sells a Ported housing, Dennis has one from another company now... The 38R comes with a ported housing...


But Bob used to (and may still I dont know) add a bit more porting to the ported 38R housing. I am not sure what he does or did to it, but it was to help with surge in the higher boost levels.

 

[lincolnlocker]

Yep - its been done before. In fact BDP dynoed a truck not too long ago with a 38R and an additional gate and it made some pretty good numbers.

Wasnt that with a non wg housing and custom gates?

 

[fatsix]

Funny this thread pops up. I was just thinking about wastegating my D66 in a compound setup. I Dunno how well this would work. I'm not familiar with compound setups at all. I guess I have some reading to do.

 

[CurtisF]

But Bob used to (and may still I dont know) add a bit more porting to the ported 38R housing. I am not sure what he does or did to it, but it was to help with surge in the higher boost levels.

Frank and I both have Bob's porting on our turbos.

That's why I wondered if it affects boost levels at all.