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Discussion Starter #1
I was thinking, which isn't too often these days, anyway I was wondering why no one decides to keep one stock turbo, and add a 13G or 15G for the other turbo....I would think this would give a excellent low rpm and high rpm boost range...The stock turbo will allow for quick spool up and a quicker response, while the larger turbo would pick up the slack in the higher rpm range and handle the rest....Is this a valid thought process or am I just a retard???

Seems like it could save some $$$$ too.....
 

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Senior Member "Go Pig Go"
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this isnt possible because our turbos run tandomly and not sequentially like the Supras and Rx-7's
 

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Senior Member "Go Pig Go"
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this isnt possible because our turbos run tandomly and not sequentially like the Supras and Rx-7's

So if you add one turbo on one side that flows more air than the other you would get some really fucked up boosting.

So one stock and one larger turbo mounted in same fashion as they are now wouldnt work.
 

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Badassical Baddage
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Its possible, I don't know about the gains, but you could bolt up any turbos you wanted on there in any combination and they'd work, might not provide good results, but they'd work
 

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The way I understand it is that the V-6 engine in the 3/s has two exhaust manifolds, one for each bank. If you leave a small (stock) turbo on one and but a big turbo on the other, you've got one bank running with like 12-15 psi and the other and whatever huge amount you want. This can't be good for the engine. You would also probably have to get some kind of electronics to get that to work. i would think that it could be possible if you have a custom manifold that connects BOTH banks to the turbos, almost like what would be done if you run a big single turbo alone, you just gotta ad in the smaller with it. I would think though, this would be very expensive and hard work.
 

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Running With Scissors
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You'd need 2 boost controllers, but other than that, I think it would work. Have one turbo that you know spools at say 2500 and a larger that spools at 4000. You'd just have a lot less power than usual until you hit 4000. So unless you found a turbo that pushed more air than a stocker, but spooled at the same time, you'd still be hurting for that low end power.

Also, as long as the two turbos didn't prooduce vastly siffernt levels in backpressure, I don't think running two differnt ones would affect the airflow into the different banks. Our Y-pipe would still funnel the air into one inlet. :confused:
 

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Hellfire Master
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2,666 Posts
What about a twin sequential setup? That seems to have potential for some serious coolness. Picture it: two 13 or 15 g's strapped to two gt399's. Two boost controllers... Hellified tuning job, but very, very cool. I'll start on this one after I successfully transplant the Toyota Tundra V8 into a Supra and twin turbocharge it. Heh heh heh... no not really.

devilmanVISA
 

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just a guy
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I think it has basically already been said, but having different sized turbos could create a host of problems....

There would almost certainly be a differnce in backpressure between the front and rear banks of cylinders. This is not an optimal condition for any engine. That is why you don't see racing engines with unequal length headers and such. The better each cylinder is matched to the others (flow, fuel, spark, etc) the better the whole engine will run.

Another obvious problem would come at about 5000 rpms when the stock turbo can't hold (let's say) 15psi and begins to drop to around 11psi. The large turbo will likely be pushing a full 15 psi...since air from each turbo comes together at the Y-pipe you'll end up with positive pressure on the output side of the small turbo. It probably wouldn't be enough to stall it, but it seems like it would definitely slow it down, causing even more engine unbalance (less power).

Running two boost controllers would only work if you held max boost to what the small turbo could provide. At best, you'd be limited by your weakest link (the small turbo).

Still, it would be cool if you'd like to try it and tell us about it :)
 

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it could work

If you think about how a turbocharger works, the tubine is turned by the exhaust gases from the engine. In the case of our engines the compressed air from the 2 turbos come into one inlet. So if you were to leave one stocker installed to kick in lets say about 3500RPM and a larger unit that is properly sized to come in at about 4500RPM, both turbos are sending air to the same inlet. Now you would not need to 2 boost controllers, unless you wanted to adjust the boost, (think about it did your car come with a boost controller) you just need wastegates to control exactly how much boost you really want. Now the downside (every good idea has a down side:( ) During the time the stocker unit is creating boost it is only from 3 cylinders rather than 6. So your limiting factor is going to be how much exhaust gases are being pushed out from 3 cylinders that can create enough boost to push 6 cylinders until the larger unit starts creating boost. The second downside is....we all know that the stock turbos can not hold that much boost through redline. So the second(larger) turbo would have to be big enough to drive all 6 cylinders when the stocker runs out of breath. Thirdly (if thats a word:confused: ) when that stocker is at its full capacity it just blowing a lot of hot air. All in all it theoretically it could work. Probably not the best mod but it could work. Try using one 13G and one TD05 16G or hell what the f**k go with a 20G. Just my $0.05
 

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Hellfire Master
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So you're telling me we couldn't run tandem sequential turbo setup? The supra does it. Why couldn't we do it in tandem? Have a small ball bearing turbo at each manifold that builds up to a specified psi and then wastegates to a pair of big nasty turbos (gt399's or t66 or something equally huge). Your boost would spool really quickly at low rpms due to the small ball bearing turbo and could increase boost at higher rpms as the smaller one wastegates to the larger one and it spools up before the smaller one wastegates completely. It seems tecnologically feasible doesn't it? If not, then why does it work on a supra? I realize that a supra only has one sequential setup and is an inline 6, but we should be able to recreate this with twin sequential setup on our V6 engines. A 3:2 cylinder to turbo ratio... Twon on one bank and tw on the other.

devilmanVISA
 
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