someone should try it

Dzchey21 · Jul 14, 2011

stock turbos in the valley, with a big atmospheric turbo mounted off to the side in one fender, probably spool retarded fast, make good power, just have to double gate it i bet... who's gunna try it?

JAP · Jul 14, 2011

No 6.4 expert for sho. But wouldn't the stock high pressure turbo become a major resriction? Just wondering.

Dzchey21 · Jul 14, 2011

I dont think so, the turbo will really never become a restriction, there are dodge guys running A8000's (hx82's) with A3000's (59mm turbo) making well over 800 hp and drive awesome, the problem comes on the turbine side of things, hince the two wastegates. On a street truck it would be fine, street driving would require little from the gates ect, but under full throttle dump all that drive pressure into the big turbo, let the stockers soak up some of the pressure ratio, bingo 70psi of boost i would imagine, with the turbos all within their maps, because now you have 3 turbos dividing the pressure ratio down, instead of 2, or one in a single turbo application

JAP · Jul 14, 2011

Makes sense.

I was just always under the ASSumption that the hp was really small. What are the top fuel only wastegated 6.4 numbers?

Dzchey21 · Jul 14, 2011

JAP said:
Makes sense.

I was just always under the ASSumption that the hp was really small. What are the top fuel only wastegated 6.4 numbers?

they are pretty small, i want to say its a 65/56mm turbo combo, so yes they are pretty small turbos. Top fuel only is 620 or something like that, jeff dodds hp calculated to 650 ish on stock turbos, no gate.

That being said the total mass air flow is determined by the atmospheric turbo anyway, so put a 88mm gt47 out front, two 44mm gates, let it eat... kinda wish i would have tried it honestly.

Piping would have kinda been a bastard, mostly on the hot pipe, but the inlet pipe from the big turbo to the stockers would have been easy because the inlet is already 3 inch, easy hose connection, little extra piping would be required compared to a big twin set up where everything must be fabricated

cfdeng7 · Jul 14, 2011

That's so weird you said this because there's that 7.3 turbo thread with talk about using the stocker as the high pressure and was thinking how this would work/if it would work on a 6.4. Granted I know very little when it comes to the technical stuff about turbos but my brain likes to try haha. I also thought about if a procharger feeding the stockers would work? Would eliminate the bastard child of a hot pipe and plumbing would be simple. Would it work hell I have no idea.

Erikclaw · Jul 14, 2011

Sounds interesting, I guess the big atmospheric would just "push" all the extra air through the stockers? That setup with a set of tow powers would be sweet.

JAP · Jul 14, 2011

Why double gate? I understand going around the stockers, but Im guessing the second gate would be around the atmospheric?

Erikclaw · Jul 14, 2011

I am pretty sure you would have to gate the atmospheric.

David S. · Jul 14, 2011

Erikclaw said:
Sounds interesting, I guess the big atmospheric would just "push" all the extra air through the stockers? That setup with a set of tow powers would be sweet.

That would be so awesome

JAP · Jul 14, 2011

Erikclaw said:
I am pretty sure you would have to gate the atmospheric.

Just asking. I was always under the assumption that with the right size exhaust housing that it wouldn't require a gate. I'm just interested. Not trying to say anything definitive.

jdgleason · Jul 14, 2011

Im listening...... I feel like mid range and top end may suffer some with stock housings? What do you think egts would do?

Erikclaw · Jul 14, 2011

I am no expert either, with the drive pressures so high on big tunes almost requiring a wg. I would think having a big atmospheric would require it and then on on the stockers to take care of the rest. Especially if more fuel is applied.

Erikclaw · Jul 14, 2011

jdgleason said:
Im listening...... I feel like mid range and top end may suffer some with stock housings? What do you think egts would do?

If Dustin is right, and 70psi is attainable I bet it wouldn't suffer at all. I just figure the big atmospheric would literally push the air through the stock turbos at some point? I don't know, just me thinking out loud.

jdgleason · Jul 14, 2011

Erikclaw said:
If Dustin is right, and 70psi is attainable I bet it wouldn't suffer at all. I just figure the big atmospheric would literally push the air through the stock turbos at some point? I don't know, just me thinking out loud.

Ya I understand what youre saying, what I am wondering is what the cfm would really be vs the psi they were pushing. When air is forced through a restriction (stock turbos) its gonna heat the air up, thus raising egts. Im wondering how much cfm the second atmosphere charger would add i guess.

Dzchey21 · Jul 14, 2011

cfdeng7 said:
That's so weird you said this because there's that 7.3 turbo thread with talk about using the stocker as the high pressure and was thinking how this would work/if it would work on a 6.4. Granted I know very little when it comes to the technical stuff about turbos but my brain likes to try haha. I also thought about if a procharger feeding the stockers would work? Would eliminate the bastard child of a hot pipe and plumbing would be simple. Would it work hell I have no idea.

I have a procharger bracket someone could try this on, i thought about doing that too, just not sure if the drive hp to drive the blower would overcome the amount of added air flow.

Erikclaw said:
Sounds interesting, I guess the big atmospheric would just "push" all the extra air through the stockers? That setup with a set of tow powers would be sweet.

Yes push i suppose, tow powers would be ideal honestly

JAP said:
Why double gate? I understand going around the stockers, but Im guessing the second gate would be around the atmospheric?

One gate might be enough, but i would think two gates feeding the big turbo would ensure that the drive pressure did not get too high

JAP said:
Just asking. I was always under the assumption that with the right size exhaust housing that it wouldn't require a gate. I'm just interested. Not trying to say anything definitive.

Yes your right, thats why im saying two gates to the big turbo, no gates to do the downpipe or anything

jdgleason said:
Im listening...... I feel like mid range and top end may suffer some with stock housings? What do you think egts would do?

Top end would probably be better, because higher rpms push the stock turbos out of the effieciency range, hince why they smoke more up top esp on the dyno, the big turbo would now supply enough air to clean all that up, as well as keep the stock turbos in their effiecency range, so they wouldnt just be making heat.

EGTs would go down at WOT, prob stay the same cruising as stock turbos

Erikclaw said:
I am no expert either, with the drive pressures so high on big tunes almost requiring a wg. I would think having a big atmospheric would require it and then on on the stockers to take care of the rest. Especially if more fuel is applied.

hince to gates, after you get to cranking 35-40 psi of boost, basically start dumping that drive pressure to the big turbo, and then eventually bypassing most exhaust energy into the big turbo, letting the big turbo do alot of the work.

Erikclaw · Jul 14, 2011

That is a good question. I think the only way to get that answer is to try it. LOL Or one of the guys here that understand all things turbos on this site need to chime in.

Posting when Dustin answered a lot of it. I wasn't thinking in terms of two wg's on the big atmospheric, makes sense.

JAP · Jul 14, 2011

Erikclaw said:
I am no expert either, with the drive pressures so high on big tunes almost requiring a wg. I would think having a big atmospheric would require it and then on on the stockers to take care of the rest. Especially if more fuel is applied.

Seems like the only reason to gate the atmospheric would be to keep the PR down in between stages.

What kind of boost numbers are stock turbos standing up to these days?

Powerstroke Cowboy · Jul 14, 2011

If I had a 6.4L Dustin I would do just what you just suggested..

I think it is a killer idea..

JAP · Jul 14, 2011

Dzchey21 said:
I have a procharger bracket someone could try this on, i thought about doing that too, just not sure if the drive hp to drive the blower would overcome the amount of added air flow.

Yes push i suppose, tow powers would be ideal honestly

One gate might be enough, but i would think two gates feeding the big turbo would ensure that the drive pressure did not get too high

Yes your right, thats why im saying two gates to the big turbo, no gates to do the downpipe or anything

Top end would probably be better, because higher rpms push the stock turbos out of the effieciency range, hince why they smoke more up top esp on the dyno, the big turbo would now supply enough air to clean all that up, as well as keep the stock turbos in their effiecency range, so they wouldnt just be making heat.

EGTs would go down at WOT, prob stay the same cruising as stock turbos

hince to gates, after you get to cranking 35-40 psi of boost, basically start dumping that drive pressure to the big turbo, and then eventually bypassing most exhaust energy into the big turbo, letting the big turbo do alot of the work.