Compound Boost?

[pokeytemplar]

Well my turbo thread kinda side tracked into this so I started a new one just for it.

Would it work for our 10's? Yes and no. It is all in how you set it up.
I think it is a viable option for the Roe guys that want more power. Add a single turbo kit to the mix and you have "no traction all the time" .
If you have nothing then I believe a turbo setup can provide all of the power you could ever use on the street and probably the strip as well.

If I was rich I would love to do a quad turbo setup on our 10's. Quick spool and nice numbers down low and then the power would just grow and grow.:rock:

 

[Scrambler1]

As I said in the other thread, compound boost is a very cool setup. Instant torque with turbo like top end. The shop working on my truck recently finished an 03 Mustang Cobra with compound boost. It put down over 1000hp on boost. I haven't driven it but those who have say it is a monster on the street. A couple of possible issues...

1. Tuning is VERY difficult, I personally don't think a VEC or SCT could get the job done.
2. VERY high manifold pressures as the turbo tries to force more air through the supercharger than it was designed for.
3. Wow would this ever be expensive
4. Less total hp than a comparable turbo setup.

I've been thinking about this since last night and I don't think it would be worth it from a performance standpoint on our engines. Mustangs have serious lag issues with big turbos because of their small displacement (281ci) Our engines on the other hand are over 500ci and can spool up a big turbo and make big power very low in the RPM band if setup correctly.

I'd be more interested in a compound setup similar to what you see on Cummins engines. click her for example Same type deal, large displacement engine almost instantly spools the smaller turbo which spools up the large one and then the large one runs like hell without pushing through a restriction.

 

[JMB Justin]

Its been done on the FGT's too, this place has dyno comparisons of with/without blower:

The biggest challenge is tuning as Joe said, and having lower boost settings is out too, so some of the turbo advantage is gone. I say why complicate things, when turbos work so well on these heavy trucks already?

Justin

 

[Ram From Hell]

I say why complicate things, when turbos work so well on these heavy trucks already?

Why be norml?:dontknow:

It's cool being different.

 

[pokeytemplar]

As I said in the other thread, compound boost is a very cool setup. Instant torque with turbo like top end. The shop working on my truck recently finished an 03 Mustang Cobra with compound boost. It put down over 1000hp on boost. I haven't driven it but those who have say it is a monster on the street. A couple of possible issues...

1. Tuning is VERY difficult, I personally don't think a VEC or SCT could get the job done.
2. VERY high manifold pressures as the turbo tries to force more air through the supercharger than it was designed for.
3. Wow would this ever be expensive
4. Less total hp than a comparable turbo setup.

I've been thinking about this since last night and I don't think it would be worth it from a performance standpoint on our engines. Mustangs have serious lag issues with big turbos because of their small displacement (281ci) Our engines on the other hand are over 500ci and can spool up a big turbo and make big power very low in the RPM band if setup correctly.

I'd be more interested in a compound setup similar to what you see on Cummins engines. click her for example Same type deal, large displacement engine almost instantly spools the smaller turbo which spools up the large one and then the large one runs like hell without pushing through a restriction.

I have to disagree with #2. High Manifold pressures is due to the compounding of boost. Twin screw or root is further compressing the air that is already compressed by the turbos multiplying the effect (not adding).

And partially disagree with #4. Peak might be down (slightly) but average power would be considerably up. Would the additional power be usable in a Ram srt-10. Most likely no but an AWD setup? Hmmmmm......

 

[DevilDawg3097]

Hey this for me is the best of both worlds I used to be a turbo guy, until I got my first s/c which was the roe but I am sorry no turbo without a big boost of juice will spool faster for off the line which in the 1/4 is what we want but I do notice it tappers off dramaticly at 120-130 then its just like an N/A unless I down shift but that would be my purpose for throwing the turbo in the mix mainly for Top end. I know everyone says traction but I believe I may have that whipped we shall see. But if I have most of everything for the turbo setup except the manifold:marchmellow: so I would be able to put everything into tuning so is it doable?

 

[pokeytemplar]

Hey this for me is the best of both worlds I used to be a turbo guy, until I got my first s/c which was the roe but I am sorry no turbo without a big boost of juice will spool faster for off the line which in the 1/4 is what we want but I do notice it tappers off dramaticly at 120-130 then its just like an N/A unless I down shift but that would be my purpose for throwing the turbo in the mix mainly for Top end. I know everyone says traction but I believe I may have that whipped we shall see. But if I have most of everything for the turbo setup except the manifold:marchmellow: so I would be able to put everything into tuning so is it doable?

Yea it is doable. Your in for more of an investment than just a manifold upgrade. Fuel system, PCM, etc will need upgraded as well. It could take it's time spooling since the Roe is taking care of the power down low and that would also bring the power in smoothly instead of being "peaky".

 

[DevilDawg3097]

Yea it is doable. Your in for more of an investment than just a manifold upgrade. Fuel system, PCM, etc will need upgraded as well. It could take it's time spooling since the Roe is taking care of the power down low and that would also bring the power in smoothly instead of being "peaky".

only thing I am missing for my fuel system is fuel rails and injectors (which will be on the way In a week or so) Like I said I have alomost everything I was gonna do a turbo on my truck before I got the roe from kyle. Plus I did not have a manifold but this wouldnt be until next winter If I did, I am really just wanted to stay at 800hp total with my nos and After I am done, well see how long I go before I want to join the elite and try and break 1000hp. But after doing my build, I am too fucking lazy after work to want to come home and do mor wrenching so well see But I do want to get all the info I can just like everything else before I jump in:marchmellow: And You fugger just keep puttin more shit into my noggin stop,dont stop

 

[ZCx]

Why be norml?:dontknow:

It's cool being different.

if we were "norml" we would not have these awesome trucks
:rock: :burnout: :rock: :burnout: :rock: :burnout: :rock: :burnout: :rock: :burnout: :rock: :burnout:

yep:congrats:

 

[ZCx]

I have to disagree with #2. High Manifold pressures is due to the compounding of boost. Twin screw or root is further compressing the air that is already compressed by the turbos multiplying the effect (not adding).

And partially disagree with #4. Peak might be down (slightly) but average power would be considerably up. Would the additional power be usable in a Ram srt-10. Most likely no but an AWD setup? Hmmmmm......

got to throw some info in on #2 also........

bein a truck mechanic for gettin to be more years than i care to admit, Detroit ran "compound" boost for years on their 2 stroke engines.
when the turbos got to be more efficient started gettin low power complaints & seemed more blower drive failures.

the Detroit engineers figured out that the turbo was puttin out more air than the blower could handle & actually tryin to stop the blower.

they put a by-pass valve in the end plate. and man these things came alive.

so something like that set up would solve some worries on this set up, seems like.

my .02 worth :rock: :rock: :rock:

 

[DevilDawg3097]

got to throw some info in on #2 also........

bein a truck mechanic for gettin to be more years than i care to admit, Detroit ran "compound" boost for years on their 2 stroke engines.
when the turbos got to be more efficient started gettin low power complaints & seemed more blower drive failures.

the Detroit engineers figured out that the turbo was puttin out more air than the blower could handle & actually tryin to stop the blower.

they put a by-pass valve in the end plate. and man these things came alive.

so something like that set up would solve some worries on this set up, seems like.

my .02 worth :rock: :rock: :rock:

Before that article pokey sent me, I knew I have seen a compound boost set up but couldnt remember where and knew it wasnt a gasser. You just said it. That was the POS we where learnded on at the marine corp engineer school, and that was the last time I seen it They taught us to fix shit we where never gonna see again :marchmellow:

 

[pokeytemplar]

got to throw some info in on #2 also........
bein a truck mechanic for gettin to be more years than i care to admit, Detroit ran "compound" boost for years on their 2 stroke engines.
when the turbos got to be more efficient started gettin low power complaints & seemed more blower drive failures.

the Detroit engineers figured out that the turbo was puttin out more air than the blower could handle & actually tryin to stop the blower.
they put a by-pass valve in the end plate. and man these things came alive.
so something like that set up would solve some worries on this set up, seems like.

my .02 worth :rock: :rock: :rock:

The Detroits are Root style correct? That would most likely explain them choking on the denser air. The twin screw differences in design should eliminate that problem.

As the turbo's build boost (ie 14psi) then the Roe would just be moving 1000cfm of air with twice the density. Cool thing is you could intercool each stage, greatly reducing the total load required if there was only one.

 

[pokeytemplar]

And You fugger just keep puttin more shit into my noggin stop,dont stop

Ha Ha and I haven't even mentioned to you all of the other cool modifications I have planned. How about this one. Pop the hood and the only accessories you can see is the dry sump pump, maybe a power steering pump, and the twin screw (maybe). However, the alternator and front/rear A/C will all be functional.

Trying to find out what a Whipple big enough for my build will cost. The Roe kit (New or Old) is way too small. Even the w245ax @ 2500cfm will move just enough air for my street power goals. The w305ax looks to be the best fit (3400cfm peak) if I ever wanted to run more than pump gas.

Money, unfortunately, drives some of my decisions and if Turbo's can provide the same power (we all know it can) for a LOT less then that will have to be the way I go.

 

[dnz28]

The Detroits are Root style correct? That would most likely explain them choking on the denser air. The twin screw differences in design should eliminate that problem.

As the turbo's build boost (ie 14psi) then the Roe would just be moving 1000cfm of air with twice the density. Cool thing is you could intercool each stage, greatly reducing the total load required if there was only one

Detroits did not choke they where being feed to much air stressing the rotors of the blower(s). sometimes the drive would stripout(like some said) or the rotors would shred to pieces and dust the airbox, the bypass provided the relief on the blower rotors to prevent failure. the blowers mainly put out about 7psi but sometimes they would go crazy like on a 16v92tib that turbo pumped out 28psi. they also aftercooled under the blower a after cooler was placed, or it was on top on 71v series.

 

[ZCx]

yep. Roots Style.

 

[ZCx]

Detroits did not choke they where being feed to much air stressing the rotors of the blower(s). sometimes the drive would stripout(like some said) or the rotors would shred to pieces and dust the airbox, the bypass provided the relief on the blower rotors to prevent failure. the blowers mainly put out about 7psi but sometimes they would go crazy like on a 16v92tib that turbo pumped out 28psi. they also aftercooled under the blower a after cooler was placed, or it was on top on 71v series.

low P.S.I. high volume.

don't remember any aftercoolers on the 71's
only 92's.

 

[dnz28]

I work in the truck/maine industry yachts require a lot of power to move. 92s used engine coolant 71s used raw water, on trucks 6/71 sometimes have a aftercooler, that is a pain in the ass to replace. on the 71s some would call it a intercooler some aftercooler, its after the turbo but before the blower.

 

[bigike]

Ok compound boost.

Lets talk about large engines 12,000 cubic inch diesels.

In a compound boost set up you would have a blower to start the engine and run it up to temp. Once you've reached operating temp (because as TREY knows Heat spools the turbo). When the turbo comes on the blower goes into bypass. When a blower isn't in bypass it is in boost, when it's in boost it's creating heat.

Single Turbo is the way to go. I bet that mustang would pull 1000 hp on the turbos. I wont want to be around when the blower lets go from over spolling. If you've got a 10 pound blower with 20 pound turbos pushing into it. You are creating a restriction. Create a restriction and you create heat.............................

Now how bout a 8.3L Whipple. Thats an Idea!

 

[bigike]

Detroits needed it to start also on 149TI's the cooler was under the blower in the airbox............... I love screamers!

 

[ZCx]

screamin demons. enjoyed them when were around. :rock: :rock: :rock: