Twin Turbo

[2_Liter_Turbo]

Has anyone twin turbo'd or have heard about someone twin turbo-ing a KA? Would there be any advantage (throttle response) to run a twin turbo setup? They twin turbo inline six's why not an inline four? I think it would be very interesting project to say the least.

[crzycav86]

I think a member by the name of Andrave was doing a TT project.. I don't know how far he's gotten, but he'll pop into this thread eventually.

[MarkEmark]

Has anyone twin turbo'd or have heard about someone twin turbo-ing a KA? Would there be any advantage (throttle response) to run a twin turbo setup? They twin turbo inline six's why not an inline four? I think it would be very interesting project to say the least.

There's a reason no one has done this yet...think about how much of a PITA it will be with TWICE of everything needed for a single turbo install....all the piping, oil lines, wastegates, ugghh, it makes me nervous just thinking about it. If anyone does this successfully it will be more for the "awe" or "gimmick" factor than anything else. It's complicated enough adding and plumbing a t/c system to a previously n/a engine, but 2 turbos would just be a headache IMO. Bottom-line, it's impracticle, unfeasible, and superfluous when people are making 533+ rwhp on a single turbo setup...

[2_Liter_Turbo]

If it can be done, it would result with tons of power, but also awesome throttle response due to the twin smaller turbos wouldn't you think?

[andrave]

it would be similar to a large single turbo. and yes, its a pain in the ***, you need twin oil feeds, twin downpipes, twin inlet intercoolers, twin air cleaners, twin oil drain bungs welded onto your pan... packaging is a real ***** too. I finally got my car running and I'm working on the manifold now. Yeah... its a *****. But its cool. twin turbo just sounds better.

[2_Liter_Turbo]

Do you have any pictures man? I would love to see your setup.

E-mail is [email protected] if it's easier

[TheOne]

usually its cause of the installin, as everyone says its a PITA, but what about exhaust flow? will 2 runners really flow good to use 2 turbos?.(this is a question, not bein a smartass)

[andrave]

why does everyone keep thinking of turbos like "OH, WOW, ITS A TURBO..."turbos are little air pumps, and they come in many different sizes.Look at the turbos that we are talking about... the twin T25's on my setup would be lucky to support 350 hp. They have tiny *** .48 turbine housings, you can't fit two fingers into the turbine inlets....Both of them together are less turbo than the large singles the guys that are posting 400+ hp are using.Just like a supra or a skyline, you can make big numbers with either, and the spool up times are pretty similar. its just a matter of airflow.

[AmoebAssassin]

Good luck trying to spool twins on two exhaust pulses per turbo...You're better off with a decently sized single. People these days just want twin turbos for name alone.

[Warped]

it depends on what you are going for a track slut yeay go for a t28 followed by a t-66 and yea you got a ***** of a track slut but why all the extra work for what there is no need for a ka24dett at all unless you are a drift ***** and do 2 t25 i guess and make full boost on both at about 3400 rpm , thats just me,.. but my single turbo combo i hope to make full boost at 3000 rpm and have fun the whole way and when i upgrade my fuel watch out

[drifts14x]

Props to you andrave for pulling it off, but to everyone else, Single turbo is the only justified pursuit of boost, don't bother with the complexities that 2 turbines can provide, you don't have a need for it. Andrave can stay unique, more power to the man.

[captainoftheknights]

hi this is my first post here so here goes

I have a 99 dakota with a v8 that i have been wanting to turbo for a long time, no money but plenty of research.there are two types of turbo systems with two turbos. there is biturbo and twin turbo, now i am not sure which one is which but one is where you just have two turbos in the system like the 300zx supra and the way i want my truck. the turbos dont intereact with eachother there is just more than one. then you have sequential turbos like some porches have then you have one smaller one and one larger one. so you get the quick spool up of the small one and the big power of the large one. this is normaly used to make a car more streeable so tha tyou dont have this huge yank of power when the large turbo spools up. i havent seen many TTs in 4 bangers but i asume your system is sequential

i know i ramble but i am at work so i had to be quick

Brian

[andrave]

mine are skyline GTR turbos. parallel turbos. I don't see why two exauhst pulses would be unable to spin a small turbo any less than 4 could spin one twice as large...thats deep.

[captainoftheknights]

so deep that.... um yeah thats pretty deep

[AmoebAssassin]

mine are skyline GTR turbos. parallel turbos. I don't see why two exauhst pulses would be unable to spin a small turbo any less than 4 could spin one twice as large...thats deep.

It's a matter of lag between the pulses. Four cylinders into one turbo provides a more stable energy delivery to the turbine. The problem with twins on a four cylinder engine is not only the two exhaust pulses per turbo per two revolutions but the delay in between the pulses during which the turbine will decellerate.

[madbouncy]

Good luck with your setup Andrave, look forward to seeing the dynos of it in action. As for TT setups on 4 cylinders, it's all just how you do it, as long as you pulses are spaced apart equally it should be ok. Also, there's twin turbo kits out there for the WRX that do the same thing about using a turbo for each 2 cylinders. obviously, it's different for a wrx since it's a boxer engine, but if I could find some dynos of the setups, it would show that it works fine.

Didn't have any luck finding the TT kit I saw before. Oh well.

[andrave]

its no different for a boxer engine...lag between the pulses? sure, ok, whatever.

[Nismo_Freak]

Good luck with your setup Andrave, look forward to seeing the dynos of it in action. As for TT setups on 4 cylinders, it's all just how you do it, as long as you pulses are spaced apart equally it should be ok. Also, there's twin turbo kits out there for the WRX that do the same thing about using a turbo for each 2 cylinders. obviously, it's different for a wrx since it's a boxer engine, but if I could find some dynos of the setups, it would show that it works fine.

Didn't have any luck finding the TT kit I saw before. Oh well.

There are plenty of EJ20 bi-turbo engines overseas.

I'd still estimate spool-up of around 3500 (initial) and 4500 before sizeable power is made. Definately not the most ideal setup but a cool one at that.

[Nismo_Freak]

hi this is my first post here so here goesThere is biturbo and twin turbo

They are the same... European cars typically are called "BiTurbo" (adapted from the Italians and Germans) and the Japanese stuck with "Twin Turbo".

hi this is my first post here so here goesThere is biturbo and twin turbo, now i am not sure which one is which but one is where you just have two turbos in the system like the 300zx supra and the way i want my truck. the turbos dont intereact with eachother there is just more than one. then you have sequential turbos like some porches have then you have one smaller one and one larger one. so you get the quick spool up of the small one and the big power of the large one. this is normaly used to make a car more streeable so tha tyou dont have this huge yank of power when the large turbo spools up.

JZA80 Supras are sequential, as are FD3S RX7's

Skyline GTR's (R32-34) have stepped boost pressure to mimic the smoothness of the sequential but the turbos spool in parallel.

There are no stepped turbocharger designs that I am aware of in a normal production car. The Porsche Flat-6 BiTurbo engines use equally sized turbochargers.

Also, the turbos even in sequential mode have a tendency to be very rough in such cars as the FD3S where the primary and secondary turbochargers tend to add alot of power quickly when you hit the transition point.

[madbouncy]

The only thing I meant that was different about the boxer engine was that you'll have an exhaust manifold on each side of the engine, so it almost seems natural to have two turbos on it. One for each bank of cylinders. Where as with our inline 4, you'll have to have the manifolds go different ways so you have the room for two turbos and their piping. It's nothing hard, just have to watch yourself and measure carefully.

Nismo, do you think you could explain what twin scroll turbos are? I searched and all I found was that it has two spots that the exhaust gases enter. It said it did that so the pulses wouldn't hit each other. I thought if you had a good manifold, the pulses would all hit at different times anyways? It seems odd to have a special turbo made rather than a good manifold that would benefit any turbo used with it. Is it only for engines that have multiple cylinders firing at the same time?

[Nismo_Freak]

The only thing I meant that was different about the boxer engine was that you'll have an exhaust manifold on each side of the engine, so it almost seems natural to have two turbos on it. One for each bank of cylinders. Where as with our inline 4, you'll have to have the manifolds go different ways so you have the room for two turbos and their piping. It's nothing hard, just have to watch yourself and measure carefully.

Nismo, do you think you could explain what twin scroll turbos are? I searched and all I found was that it has two spots that the exhaust gases enter. It said it did that so the pulses wouldn't hit each other. I thought if you had a good manifold, the pulses would all hit at different times anyways? It seems odd to have a special turbo made rather than a good manifold that would benefit any turbo used with it. Is it only for engines that have multiple cylinders firing at the same time?

A twin scroll turbocharger basically has two channels for the exhaust gas to enter. The manifold is designed so that no two sequentially fired cylinders of the engine feed the same scroll. This prevents the pulses from interfering with each other as they pass through the housing.

It was used in Evos and RX7's primarily.



Bad pic.



Better pic.

No engine should fire two cylinders at the same time, it would more than likely snap the crank at some point. Twin scrolls can be implimented on just about anything with > 2 cylinders per turbo. It would be moronic to use twin twin scrolls on a 4-cyl. engine due to it already following the principle of the design.

You are correct about manifold design, however noted in the vehicles this turbo was typically used in they were limited by space constraints for the manifolds and/or just used it as a selling point and a cheaper way around alot of R&D. Mitsubishi was really one of the only companies to really get into the twin scrolls due to their heavily produced diesel engines using the same technology to reduce emissions.

[andrave]

mitsu uses twin scroll on some of the evo's, doesn't it? I think I remember reading about it. There is only one car I can think of that runs stepped turbos in sequential, and that is that porsche uber supercar they made a decade and a half ago. I've heard on those boost hits like a sledgehammer around 5,000 rpm and doesn't let up till you hit the revcut and your head bounces off the windshield...lol

Anyway someone come weld my manifold for me, its a lot of work.

[captainoftheknights]

as far as the bi-turbo and twin turbo, thats just what i have read while doing research on the web about multiple turbos. not a big deal. i was only trying to state that on a 4 cylinder engine you would probably not want to split the cylinders up because of poor exaust presure from only two pulses. that is unless you are talking about a boxer engine but thats allong the same lines as twin turboing a v engine, you can get the turbos closer and get better temps for better turbo performance. plus much easier plumbing

[andrave]

how would a boxer give you "better temps for better turbo performance" than an inline engine?

[Nismo_Freak]

how would a boxer give you "better temps for better turbo performance" than an inline engine?

He was assuming this because the manifolds could be more easily made shorter due to not having to route the manifold around another in the case of an inline 4 setup.

The idea is to maintain mass flow through the turbo. The more thermal energy in the exhaust the better but this is not what truely drives the turbocharger. Certain motors like the rotary engine are exceptional at spooling larger turbos because they effectively are the best at it... they produce alot of pulses into a short two runner manifold that have very high temps. The result is a massive amount of exhaust manifold pressure before the turbine housing resulting in a greater deltaP across the blades of the turbine. This pressure differential is what causes air to pass through at an extremely high rate which translates in to axial energy. The temperature of the exhaust gas helps to maintain higher pressure in the manifold since a hotter gas occupies more volume, and the manifold is not a variable volume receptical... that is unless you have a cheap Ebay manifold that cracks

[sr240det]

this one is for the idiots that say there isnt a KA-TT.....

http://www.zilvia.net/f/showthread.php? ... th...turbo



good luck to you ElNegro if you want to put some bling under your hood...... it works just as good as a larger single turbo....

[C-Kwik]

there are two types of turbo systems with two turbos. there is biturbo and twin turbo, now i am not sure which one is which but one is where you just have two turbos in the system like the 300zx supra and the way i want my truck. the turbos dont intereact with eachother there is just more than one. then you have sequential turbos like some porches have then you have one smaller one and one larger one. so you get the quick spool up of the small one and the big power of the large one. this is normaly used to make a car more streeable so tha tyou dont have this huge yank of power when the large turbo spools up. i havent seen many TTs in 4 bangers but i asume your system is sequential

Actually, the MK4 Supras used a Sequential Twin Turbo System. the term sequential is misleading to me though. It's more of a 2-stage turbo set-up. One turbo is always ready to boost. As load and RPM increases, a couple of valves open allowing the second turbo to spool, but does so in parallel to the first turbo. Both turbos are the same size. And I am not aware of any porsche or factory turbo car for that matter that uses dual turbos of unequal sizes. It would have to be a staged set-up in order to take advantage of a small turbo's spool as it would just split the airflow at some percentage(which would change based on efficiency, boost and airflow) between the two turbos if they were set-up in parallel. A small turbo run in parallel would likely bring down top-end efficiency as well. Not exactly ideal and not exactly what I would think is part of Porsche's philosophy.

[Nismo_Freak]

Actually, the MK4 Supras used a Sequential Twin Turbo System. the term sequential is misleading to me though. It's more of a 2-stage turbo set-up. One turbo is always ready to boost. As load and RPM increases, a couple of valves open allowing the second turbo to spool, but does so in parallel to the first turbo. Both turbos are the same size. And I am not aware of any porsche or factory turbo car for that matter that uses dual turbos of unequal sizes. It would have to be a staged set-up in order to take advantage of a small turbo's spool as it would just split the airflow at some percentage(which would change based on efficiency, boost and airflow) between the two turbos if they were set-up in parallel. A small turbo run in parallel would likely bring down top-end efficiency as well. Not exactly ideal and not exactly what I would think is part of Porsche's philosophy.

Did you even read my post? LOL.