TWO DIFFERENT TURBOS IN Parallel POSSIBLE
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Joined: Apr 2009
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Yeah, there is a big difference between an .84 & a .96.
I could see that happening as one turbo wants to come up in pressure before the other one. It won't matter separating them pre-IC as they will flow into the same plenum, or the intake of Y'd after separate IC's.
The turbo specs on the one, if you had identical ones, would work well enough for about 650-700HP with a .68 A/R with twins. Even .84's might work but response time would suffer.
This is really combination dependent. I don't know enough about what you have engine-wise, I think you posted some stuff about it in the conversion forum, but I haven't read the thread yet.
I could see that happening as one turbo wants to come up in pressure before the other one. It won't matter separating them pre-IC as they will flow into the same plenum, or the intake of Y'd after separate IC's.
The turbo specs on the one, if you had identical ones, would work well enough for about 650-700HP with a .68 A/R with twins. Even .84's might work but response time would suffer.
This is really combination dependent. I don't know enough about what you have engine-wise, I think you posted some stuff about it in the conversion forum, but I haven't read the thread yet.
Thread Starter
Staging Lane
Joined: Dec 2015
Posts: 65
Likes: 1
stock ls1 motor and 4l60e trans out of a 2000 camaro ss, i was thinking to just get smaller sep intercooler. and make them meet right at the throttle, which by that time the boost would just go right into the throttle and not back all the way down to the weaker turbo
Originally Posted by BoostedLS1CrownVic
http://www.ebay.com/itm/231054559617?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
thats 1 turbo
thats 1 turbo
If I were you I wouldn't even bother trying to make the 2 different turbos work, I would just spend the $170 and be done.
No they arnt out of stock just that seller is. Here is the same exact turbo from another seller.
http://m.ebay.com/itm/SUPER-T70-T3-ANTI-SURGE-V-BAND-EXHAUST-FLANGE-TURBO-CHARGER-TURBOCHARGER-600-HPS-/161739456927?nav=SEARCH$166
http://m.ebay.com/itm/SUPER-T70-T3-ANTI-SURGE-V-BAND-EXHAUST-FLANGE-TURBO-CHARGER-TURBOCHARGER-600-HPS-/161739456927?nav=SEARCH$166
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Joined: Apr 2009
Posts: 723
Likes: 4
Get the same turbo & try it. My guess it will be more of a top end queen with .84 turbine H's (even though its running a 73/58 turbine) & nothing much under 5,000RPM with a stock motor. It's all going to depend on how the converter loads it though...
.68's would work much better in a car like a vic for street driving, IMO. It would spool up in the 3,000-4,000RPM range & have low end torque to spare. Will still pull 6,500 all day.
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Joined: Jun 2013
Posts: 1,163
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From: Avon, Ohio
This is my junk- stock LS1, stock Cam, on LARGER turbos with larger AR's. Stock Redline. Im at 20psi around 3800-4k depending on gear. This video is looking at the boost gauge.
With an auto and lower gear ratio, my set up would actually spool faster on his car! As for a solution, I still dont know. There are a metric **** ton of potenial issues here-how about the 2 inch exhaust, or the fact that the car gaiend 40whp when the downpipe was removed? Oye!
I am local to the OP so hopefully I can take a peek and firgue out whats going on!
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I don't get what the question is? You already have it setup and it's running and making boost. So obviously it works, no?
In a pressure system, 2 unequal pressures will always take the path of least resistance. This will be the inlet to the engine. The smaller turbo isn't going to "back feed" the larger.
You will have unequal backpressure levels driving each turbo which is less than ideal. It will cause different levels of reversion on each bank. (assuming you have one bank feeding each turbo with no equalizing cross over.) This means each bank will need a different AFR and timing curve for best performance. Assuming you have an ECU capable of this you could make it work. . If you're not super concerned about your setup performing it's best it's probably "ok". I'd watch the plugs close on something like that. Your WB02 is only giving you a collective reading. Maybe install some sort of equalizer across the 2 banks as well. 2 mismatched turbos adds alot of unnecessary complication.... Basically not a good idea IMO...
In a pressure system, 2 unequal pressures will always take the path of least resistance. This will be the inlet to the engine. The smaller turbo isn't going to "back feed" the larger.
You will have unequal backpressure levels driving each turbo which is less than ideal. It will cause different levels of reversion on each bank. (assuming you have one bank feeding each turbo with no equalizing cross over.) This means each bank will need a different AFR and timing curve for best performance. Assuming you have an ECU capable of this you could make it work. . If you're not super concerned about your setup performing it's best it's probably "ok". I'd watch the plugs close on something like that. Your WB02 is only giving you a collective reading. Maybe install some sort of equalizer across the 2 banks as well. 2 mismatched turbos adds alot of unnecessary complication.... Basically not a good idea IMO...
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Joined: Apr 2009
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Your way off.
This is my junk- stock LS1, stock Cam, on LARGER turbos with larger AR's. Stock Redline. Im at 20psi around 3800-4k depending on gear. This video is looking at the boost gauge.
LSJUAN Twin Turbo Ls1 free 2 stage boost controler testing - YouTube
With an auto and lower gear ratio, my set up would actually spool faster on his car! As for a solution, I still dont know. There are a metric **** ton of potenial issues here-how about the 2 inch exhaust, or the fact that the car gaiend 40whp when the downpipe was removed? Oye!
I am local to the OP so hopefully I can take a peek and firgue out whats going on!
This is my junk- stock LS1, stock Cam, on LARGER turbos with larger AR's. Stock Redline. Im at 20psi around 3800-4k depending on gear. This video is looking at the boost gauge.
LSJUAN Twin Turbo Ls1 free 2 stage boost controler testing - YouTube
With an auto and lower gear ratio, my set up would actually spool faster on his car! As for a solution, I still dont know. There are a metric **** ton of potenial issues here-how about the 2 inch exhaust, or the fact that the car gaiend 40whp when the downpipe was removed? Oye!
I am local to the OP so hopefully I can take a peek and firgue out whats going on!
Like I said, it will depend on how the converter loads it. Which is partially, of-course, dependent on gearing.
I don't get what the question is? You already have it setup and it's running and making boost. So obviously it works, no?
In a pressure system, 2 unequal pressures will always take the path of least resistance. This will be the inlet to the engine. The smaller turbo isn't going to "back feed" the larger.
You will have unequal backpressure levels driving each turbo which is less than ideal. It will cause different levels of reversion on each bank. (assuming you have one bank feeding each turbo with no equalizing cross over.) This means each bank will need a different AFR and timing curve for best performance. Assuming you have an ECU capable of this you could make it work. . If you're not super concerned about your setup performing it's best it's probably "ok". I'd watch the plugs close on something like that. Your WB02 is only giving you a collective reading. Maybe install some sort of equalizer across the 2 banks as well. 2 mismatched turbos adds alot of unnecessary complication.... Basically not a good idea IMO...
In a pressure system, 2 unequal pressures will always take the path of least resistance. This will be the inlet to the engine. The smaller turbo isn't going to "back feed" the larger.
You will have unequal backpressure levels driving each turbo which is less than ideal. It will cause different levels of reversion on each bank. (assuming you have one bank feeding each turbo with no equalizing cross over.) This means each bank will need a different AFR and timing curve for best performance. Assuming you have an ECU capable of this you could make it work. . If you're not super concerned about your setup performing it's best it's probably "ok". I'd watch the plugs close on something like that. Your WB02 is only giving you a collective reading. Maybe install some sort of equalizer across the 2 banks as well. 2 mismatched turbos adds alot of unnecessary complication.... Basically not a good idea IMO...
Ditto on the rest.
Last edited by gtfoxy; Dec 14, 2015 at 09:47 AM.
TECH Fanatic
Joined: Jun 2013
Posts: 1,163
Likes: 16
From: Avon, Ohio
on3 67/66 (bigger than his) .81 Ar, Stock LS1 (same as his) with a M6 (worse for load/spool) and 4.10's (the worst, period!)
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Joined: Apr 2009
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The main thing I see here in what he listed as the second turbo came in a kit, for a single, on an LS motor.
That thing could have a larger compressor, turbine & turbine housing. If it's designed for a single kit there is no way that motor will spool that turbo & another one split off or on its own bank.
I wouldn't try comparing what you have to an unknown commodity. There could be a big difference in turbine wheels & to compare what you have vs what we don't know what he has, only makes it worse.
He needs to call cx racing or take it apart & measure it.
Only way to make this work, If the second turbo is way larger, is run them in series & crank the boost up. In order to make seriesed system work you need to match the compressors perfectly for the right pressure ratios & flow.
That thing could have a larger compressor, turbine & turbine housing. If it's designed for a single kit there is no way that motor will spool that turbo & another one split off or on its own bank.
I wouldn't try comparing what you have to an unknown commodity. There could be a big difference in turbine wheels & to compare what you have vs what we don't know what he has, only makes it worse.
He needs to call cx racing or take it apart & measure it.
Only way to make this work, If the second turbo is way larger, is run them in series & crank the boost up. In order to make seriesed system work you need to match the compressors perfectly for the right pressure ratios & flow.
Last edited by gtfoxy; Dec 14, 2015 at 06:21 PM.
Thread Starter
Staging Lane
Joined: Dec 2015
Posts: 65
Likes: 1
I don't get what the question is? You already have it setup and it's running and making boost. So obviously it works, no?
In a pressure system, 2 unequal pressures will always take the path of least resistance. This will be the inlet to the engine. The smaller turbo isn't going to "back feed" the larger.
You will have unequal backpressure levels driving each turbo which is less than ideal. It will cause different levels of reversion on each bank. (assuming you have one bank feeding each turbo with no equalizing cross over.) This means each bank will need a different AFR and timing curve for best performance. Assuming you have an ECU capable of this you could make it work. . If you're not super concerned about your setup performing it's best it's probably "ok". I'd watch the plugs close on something like that. Your WB02 is only giving you a collective reading. Maybe install some sort of equalizer across the 2 banks as well. 2 mismatched turbos adds alot of unnecessary complication.... Basically not a good idea IMO...
In a pressure system, 2 unequal pressures will always take the path of least resistance. This will be the inlet to the engine. The smaller turbo isn't going to "back feed" the larger.
You will have unequal backpressure levels driving each turbo which is less than ideal. It will cause different levels of reversion on each bank. (assuming you have one bank feeding each turbo with no equalizing cross over.) This means each bank will need a different AFR and timing curve for best performance. Assuming you have an ECU capable of this you could make it work. . If you're not super concerned about your setup performing it's best it's probably "ok". I'd watch the plugs close on something like that. Your WB02 is only giving you a collective reading. Maybe install some sort of equalizer across the 2 banks as well. 2 mismatched turbos adds alot of unnecessary complication.... Basically not a good idea IMO...
Teching In
Joined: Jun 2021
Posts: 6
Likes: 1
I had some free time today to mess around and my other turbo is still in the mail so I went ahead and ran some mismatched turbos, in this case a t04e and an hx40 on a 6.2 and documented the hptuners log of what happened. Never went over 10psi to be safe
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Joined: Oct 2016
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From: PDX-OR-USA
Wow old but a goodie..
BMW played with twins that were different sizes,, small for quick spool big one for the top end,,
They never really go tit to work, most ended up with a single to replace them under a warranty deal.
There have been others. I think the first limitation is you need a awesome EFI system. Like a motec or electromotive that can handle the electronic multiple waste-gates and blow off valves. (Wild guess.. LOL )
BMW played with twins that were different sizes,, small for quick spool big one for the top end,,
They never really go tit to work, most ended up with a single to replace them under a warranty deal.
There have been others. I think the first limitation is you need a awesome EFI system. Like a motec or electromotive that can handle the electronic multiple waste-gates and blow off valves. (Wild guess.. LOL )