What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Twin turbos on a 6.2?

OK, OK...
If you would, please refresh my memory on the function of a wastegate on a turbo. I was under the impression (probably incorrect...) that they functioned at high boost levels, to vent excess boost pressure IOT avoid engine damage. Generally at high RPM's or when suddenly letting up on the throttle to shift. I didn't know they also promoted faster spool-up - how's that happen?
 
They are simply there to prevent overspeeding of the turbo. The wastegate itself does not promote good response, rather the fact that you can use a turbo with smaller wheels that will spool up quicker, then dump exhaust so they do not overspeed. So a wastegated turbo for a certain application will generally be smaller and spool quicker, then the wastegate keeps it at an optimum speed for good effiency and keep it from grenading.
 
Obviously a non wastgated turbo would be simpler, but if a guy wanted to use the 6.5 parts how would you go about controlling the wastegate function?

Take me/us to school Tyler (or anyone else)

Rene
 
[ QUOTE ]
The wastegate itself does not promote good response, rather the fact that you can use a turbo with smaller wheels that will spool up quicker, then dump exhaust so they do not overspeed.

[/ QUOTE ]

Ahhh... The wastegate is on the hot-side... hence the term wastegate. I thought the wastegate functioned on the cold-side of the turbo.
Is a wastegate the same thing as what the ricers call a "blow-off valve"?
 
[ QUOTE ]
how would you go about controlling the wastegate function?

[/ QUOTE ]

Heath Diesel sells the Turbo-Master that bolts in place of the vacuum modulator and is basically a manually adjustable controller that maintains a preset amount of boost (set it at X psi and it will maintain it). I think it would be easy to use the 6.5 parts if you have the room./forums/images/graemlins/thumb.gif
 
Were the pre-electronic 6.5 wastegates controlled by an ECM? If they werent, then I would guess those would be the turbos to look for. This product from Heath Diesel looks interesting and the adjustability is pretty cool. Just FYI, the engines we have at Cat are usually wastegated and they are not controlled by the ECM (except some of the smaller on highway engines). It is simply a hose from the outlet of the compressor to the wastegate can. We have the luxury of being able to watch turbo speed, exhaust, and air from compressor pressures in real time, so we can fine tune the wastegate setting. Us at home would just have to experiment and see what works best without grenading a turbo.
 
Yes, the wastegate is just a valve in the turbine housing that dumps exhaust at a preset point thus limiting the speed of the turbo and keeping it in an efficient operating range for its size. AFAIK, a blow-off valve is used in high boost gas engines (Formula 1, Rally Cross) to dump boost at certain times so the pressure in the manifold doesnt back up and slow the turbo down during shifting etc.
 
[ QUOTE ]
Were the pre-electronic 6.5 wastegates controlled by an ECM? If they werent, then I would guess those would be the turbos to look for. This product from Heath Diesel looks interesting and the adjustability is pretty cool.

[/ QUOTE ]

[ QUOTE ]
The factory control used on the '92-'93 6.5's is a spring-loaded canister. It does not use vacume like the '94-newer engines.

[/ QUOTE ]

That is directly from Heath's description.

I do have room for the factory 6.5 stuff, I don't have AC and my exhaust needs upgrading anyways /forums/images/graemlins/whistling.gif

Rene
 
There ya go, it would be much cheaper than a Banks setup too. My final word on it is if you want a lot of boost for a 6.2, go with Banks, if you want good response, a factory type turbo would be best. You can always add propane or some sort of aftercooling to make the power that a Banks setup would give you.
 
In all honesty I rarely wind my 6.2 into the upper ranges anyways (where the Banks makes all it's power). Having better power lower in the rpm band would be more useful to me in real world driving conditions.

6-8 psi would be plenty I think, and probably easier on a motor with some mileage on it like mine.

Rene
 
The Banks kit uses a Garrett T04B non-wastegated turbo with a 1.00 a/r ratio. That doesn't doo much for lag, and with stock fueling (46-55 cu mm) you'll see 9-10 psi peaks. With a 4911 cranked up into the 70s, you can hit 15 psi easily.

As a side note, the ATS kit had two turbos - wastegated and non-wastegated. The non-wastegated turbo was nearly identical to the T04B. I have been unable to locate any exact specs for the wategated turbo, but you can bet that it didn't boost over the 6.2L limits.

IMO, I love my TE06H. It's wastegated, bolts into the same place that the Banks turbo does and with minimal modifications. I'm not even touching the 60s as far as fuel rate, and I can already hit 14-15 psi.

I firmly believe that the best value for the 80s style trucks is a Banks exhaust manifold and crossover pipe, a wastegated turbo (TE06H, Garrett 60-1, etc.), and piece together the rest from there. The Banks airbox is expensive as is the plenum. More effective, cheaper stuff can be hand fabbed at a fraction of the cost.

The 6.5L turbo hardware is such a headache where AC is concerned that I don't believe it's worth it.

/forums/images/graemlins/cool.gif
 
My Banks can hit 14-15 psi with the fuel only turned up enough to hit 1000 degrees max on the pyrometer. I agree with all that you say about mixing Banks parts with a better turbo. That does sound like the way to go.
 
This page was the first Google result I got - and now my brain hurts... It's a ricer-oriented page, but the writer seems to know his sh!t.
Too much turbo info!
 
Can the 94-newer 6.5 turbos be converted from the vacume control to the spring canister? is it an external difference only? I'm considering this mod more and more.
 
Yes. Bill Heath sells a turbomaster boost contoller for all the GM series turbos. However, you will still need a "boost fooler" for the MAP sensor lest you throw codes with your new found higher boost pressures.
 
I *think* he is trying to broaden the range of possible turbo donors and likely won't be running an ECM or MAP sensor on his 88 K5.

I could be wrong, but that was the impression I got.

rene
 
Yes exactly, I'm looking for donors for my 85 M1008 to piece together a system. The other info about the boost controler is good to know as well. thanks /forums/images/graemlins/thumb.gif
 
You must log in or register to reply here.

Latest Posts

Top Bottom