twin turbo
Thread Starter
Teching In
Joined: May 2006
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twin turbo alright since a twin turbo is just two turbo chargers..from what i understand..correct me if im wrong and larger turbocharger would give better high end power and a smaller turbocharger would give more low end power would it be ideal to have one large and one small turbocharger in a twin turbo setup?
***There are a LOT of variables here***
From what I've researched for the current LM7 project & found with the rear mount LT4 on my Trans Am, the advantage to twins on a flat or V motor is less plumbing and lag. The low vs. high end power is really decided by the AR/trim of the turbine housing, but the compressor AR and trim factor in as well. Turbos need to be matched to the engine based on many factors... RPM, CID, Compression, etc.
I have a 62-1 on the TA, and on the dyno it drops power like crazy over about 4500 RPM, but spools nicely at lower RPM (needs more tuning as well). A larger AR turbine housing would help out on the high end, but I'd lose some low end.
Here is a link to a good website for turbo calculators & related items:
http://www.turbofast.com.au/turbomap.html
Hope this helps.
From what I've researched for the current LM7 project & found with the rear mount LT4 on my Trans Am, the advantage to twins on a flat or V motor is less plumbing and lag. The low vs. high end power is really decided by the AR/trim of the turbine housing, but the compressor AR and trim factor in as well. Turbos need to be matched to the engine based on many factors... RPM, CID, Compression, etc.
I have a 62-1 on the TA, and on the dyno it drops power like crazy over about 4500 RPM, but spools nicely at lower RPM (needs more tuning as well). A larger AR turbine housing would help out on the high end, but I'd lose some low end.
Here is a link to a good website for turbo calculators & related items:
http://www.turbofast.com.au/turbomap.html
Hope this helps.
i thought it had something to do with exahust backpressure being different on the 2 banks...since one would hit full restriction MUCH sooner vs the other one which would be free flowing down low and have "no" backpressure compared to the other side. and again, if you get a "small" turbo ONLY for down low...at 3g rpm you get 100% backpressure because all the air cant get past the turbo...this and this alone should be the only factor. i mean there might be more factors....but this is the biggie.
Reason # 101 why not to reply after 1 AM... I missed the two different size turbos part of the original post...
This would not work for the reason stated above IF you are talking about connecting parallel turbos (one to each manifold). If you are talking about sequential (two stage, one feeding another) turbos, your idea has merit, but this would entail a lot of work and $ and would require intercooling or possibly two stage intercooling. I believe the last RX7's had this setup (I'm sure someone that has/had one will jump in on this since I know a few are here w/ Gen III motors in their cars). This setup is used on tractors in pulling contests, and they run up to 130 PSI without
. I don't see it being worthwhile on the street with the technology that is available today. I'd think the smaller turbo would end up being a restriction at some point in this setup on a large displacement V8 for street use.
Some more info is here:
http://en.wikipedia.org/wiki/Twin-turbo
This would not work for the reason stated above IF you are talking about connecting parallel turbos (one to each manifold). If you are talking about sequential (two stage, one feeding another) turbos, your idea has merit, but this would entail a lot of work and $ and would require intercooling or possibly two stage intercooling. I believe the last RX7's had this setup (I'm sure someone that has/had one will jump in on this since I know a few are here w/ Gen III motors in their cars). This setup is used on tractors in pulling contests, and they run up to 130 PSI without
. I don't see it being worthwhile on the street with the technology that is available today. I'd think the smaller turbo would end up being a restriction at some point in this setup on a large displacement V8 for street use.Some more info is here:
http://en.wikipedia.org/wiki/Twin-turbo
Originally Posted by V8 Supra Builder
Reason # 101 why not to reply after 1 AM... I missed the two different size turbos part of the original post...
This would not work for the reason stated above IF you are talking about connecting parallel turbos (one to each manifold). If you are talking about sequential (two stage, one feeding another) turbos, your idea has merit, but this would entail a lot of work and $ and would require intercooling or possibly two stage intercooling. I believe the last RX7's had this setup (I'm sure someone that has/had one will jump in on this since I know a few are here w/ Gen III motors in their cars). This setup is used on tractors in pulling contests, and they run up to 130 PSI without . I don't see it being worthwhile on the street with the technology that is available today. I'd think the smaller turbo would end up being a restriction at some point in this setup on a large displacement V8 for street use.
Some more info is here:
http://en.wikipedia.org/wiki/Twin-turbo
This would not work for the reason stated above IF you are talking about connecting parallel turbos (one to each manifold). If you are talking about sequential (two stage, one feeding another) turbos, your idea has merit, but this would entail a lot of work and $ and would require intercooling or possibly two stage intercooling. I believe the last RX7's had this setup (I'm sure someone that has/had one will jump in on this since I know a few are here w/ Gen III motors in their cars). This setup is used on tractors in pulling contests, and they run up to 130 PSI without
. I don't see it being worthwhile on the street with the technology that is available today. I'd think the smaller turbo would end up being a restriction at some point in this setup on a large displacement V8 for street use.Some more info is here:
http://en.wikipedia.org/wiki/Twin-turbo
Jose
Thnaks JZ, my old turbo book called the compound setup Tandem Turbos. I've never looked into the sequential setup and thought they were the same. It is good to learn something new, and that is an interesting concept. I can see how it would be a pain to set up, as mapping 1 or 2 non-sequential turbos can be time consuming.
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Verdad Gallardo Thread Starter
Teching In
Joined: May 2006
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alright, so another question. would it be possible on an LSx v8 engine to have a sequential turbo setup on each side of the engine since its a v8? like have a sequential setup running the 4 cylinders on one side and then anothe sequential setup for the other 4 cylinders? would this give good amounts of power and boost? im assuming it would be expensive cuz you'd need 4 turbo's right?
On The Tree
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From: houston
Originally Posted by sf887
alright since a twin turbo is just two turbo chargers..from what i understand..correct me if im wrong and larger turbocharger would give better high end power and a smaller turbocharger would give more low end power would it be ideal to have one large and one small turbocharger in a twin turbo setup?
But it presents other issues as well, many comments with in this thread have managed to address some if these issues
andy
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Last edited by smokinHawk; May 22, 2006 at 11:44 AM. Reason: nonsponser advertising.
Originally Posted by sf887
alright, so another question. would it be possible on an LSx v8 engine to have a sequential turbo setup on each side of the engine since its a v8? like have a sequential setup running the 4 cylinders on one side and then anothe sequential setup for the other 4 cylinders? would this give good amounts of power and boost? im assuming it would be expensive cuz you'd need 4 turbo's right?
. So off boost response is wonderful. Now if this board was the supra board or honda board then this discussion would be leading elsewhere. The main problem we ran across was the actuation and transition from 1 turbo to 2 done electronically.Jose
Thread Starter
Teching In
Joined: May 2006
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alright...so for an ls1 v8 rx7 is having any turbo a waste? i'd like to have it just to say and for the sound of the spooling and BOV more then anything. although the power would be nice...to run something in the 7's or 8's would a good turbo be needed?
Originally Posted by sf887
alright...so for an ls1 v8 rx7 is having any turbo a waste?
The lack of significant incentive to build a suquential turbo LS1 is what was raised... Turbo on an LS1 is a DAMN GOOD idea.
I'm having a hard enough time trying to figure out if it will be easier to run 1 or 2 on a 5.3 in a MKIII Supra. I'd hate to try & figure out how to put two per side in there! Not sure about the newer RX7- I know the engine bay in the '84 I built was REAL tight for a Gen I 383.
Turbo + Gen III= Great!
Turbo + Gen III= Great!
Originally Posted by bboyferal
Any sequential set-ups on street cars? Supra's maybe?
Sequentials done so far for the street have been Barra 240 engine, Ecotec, RB26, and Nissan Patrol.
Compound setups have been the 5.9 12V, 5.9 24V for the street and for our pulling boys, JD tractors, Case/INT, and the latest one is another 4 turbo monster 540CI 6 cylinder IHC Case/International. Makes around 2500hp on Diesel......241psi
. I absolutely love compound setups for diesels, but for gas engines.....waste of time.Jose
Originally Posted by sf887
alright...so for an ls1 v8 rx7 is having any turbo a waste? i'd like to have it just to say and for the sound of the spooling and BOV more then anything. although the power would be nice...to run something in the 7's or 8's would a good turbo be needed?
Not a waste at all if done right. Sequentials are a waste though......
Exhaust spools one turbo and forces air into another turbo instead of the intake manifold. Boost ratings of over 200 psi are possible in this way... Boost pressures NO gasoline engine can take. The unique qualities of diesel combustion make them the only motors that can take that abuse with ALOT fo fuel. I think that's the gist, but Jose knows these inside and out.
On that note, QUAD COMPOUND? Holy **** !!!
On that note, QUAD COMPOUND? Holy **** !!!
Originally Posted by bboyferal
Exhaust spools one turbo and forces air into another turbo instead of the intake manifold. Boost ratings of over 200 psi are possible in this way... Boost pressures NO gasoline engine can take. The unique qualities of diesel combustion make them the only motors that can take that abuse with ALOT fo fuel. I think that's the gist, but Jose knows these inside and out.
On that note, QUAD COMPOUND? Holy **** !!!
On that note, QUAD COMPOUND? Holy **** !!!
. Diesels really are fun...... 