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Twin Turbp Musings


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Sorry, I should proofread my posts more. I haven't been near a computer for a month, so my typing skills are sketchy right now. But yes, turbp's are a big step up from average, run o' the mill turbo's. They also cost much more, which automatically makes them much better. ;)

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Why couldn't a turbo for a 900 cc engine be used on each header pipe before the y to make the piping flow better and improve turbo response? you could pipe the pressure pipes together before the TB and have a nice setup.
There is only one problem with twin turboing a 4 cyl. If they are not sequential (one after another) the exhaust pulsations will wreak havocc on the turbo. As far as I know you have to have 3 cyl for each turbo. I will see if I can find the documentation on this. (I have read it before) but a twin sequential turbo would rock. no lag and lots of boost. or maybe a turbo and a super charger. There is a Toyota MR2 that I have seen that is set up that way. hmmmmm ;use a charger off of a tbird with a t3 from a Saab now that would be a unique setup. Or a T4 fed off of the IHI that is stock for the AE-82 turbo.....
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There is only one problem with twin turboing a 4 cyl. If they are not sequential (one after another) the exhaust pulsations will wreak havocc on the turbo. As far as I know you have to have 3 cyl for each turbo. I will see if I can find the documentation on this.

 

So how does that work on the legacy twin Turbo? IIRC, they aren't sequential

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There is only one problem with twin turboing a 4 cyl. If they are not sequential (one after another) the exhaust pulsations will wreak havocc on the turbo. As far as I know you have to have 3 cyl for each turbo. I will see if I can find the documentation on this. (I have read it before) but a twin sequential turbo would rock. no lag and lots of boost. or maybe a turbo and a super charger. There is a Toyota MR2 that I have seen that is set up that way. hmmmmm ;use a charger off of a tbird with a t3 from a Saab now that would be a unique setup. Or a T4 fed off of the IHI that is stock for the AE-82 turbo.....

Gee, that's news to me, in my more then 40 years working with turbos, I have never heard that. As for needing 3 cylinder, there are quite a few 2 cylinder turbocharged engines out there to prove that wrong. I believe the idea here is not to have sequential turbos, but to have the turbos working together, one turbocharging one bank and the othe other one the other bank. The twin turbo setup on JDM Legacys is sequential, one for lower range and one for higher range power, giving a broader power range. Superchargers rob power from the engine, and I don't consider them effecient. Using the turbos off the Yamaha motor would work, or if you could find two from the Honda turbo bike, those would work.

 

Will, it's hard to take pictures of a concept. If it were possible, you would have shown us pictures of your proposed 300hp EA82T.

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Gee, that's news to me, in my more then 40 years working with turbos, I have never heard that. As for needing 3 cylinder, there are quite a few 2 cylinder turbocharged engines out there to prove that wrong. I believe the idea here is not to have sequential turbos, but to have the turbos working together, one turbocharging one bank and the othe other one the other bank. The twin turbo setup on JDM Legacys is sequential, one for lower range and one for higher range power, giving a broader power range. Superchargers rob power from the engine, and I don't consider them effecient. Using the turbos off the Yamaha motor would work, or if you could find two from the Honda turbo bike, those would work.

 

Will, it's hard to take pictures of a concept. If it were possible, you would have shown us pictures of your proposed 300hp EA82T.

Ok I might be wrong, but one of the people that told me that is a mechanical engineer (works at boeing), and another does compressor maps at Garret (my spelling sucks today) they said that the exhaust pulsations would wreak havoc on the turbine wheel and it would not last long. (I was looking at twin turboing my 1980 rabbit with a 2.0 16v that I had built to run pikes peak) Granted I do not have the years of experiance but I do trust my sourses. Oh and with the supercharger I agree about the robing power from the engine but they make more than they take and the boost is instantanious. When you couple them both you get the best of both worlds. In the article in Import Car they said that the trubo picked up where the supercharger left off. The turbo also started to "push" the supercharger internaly and that lessened the drag on the engine at higher speeds.
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They did the supercharger/turbo combo on some of the crazy group b rally cars of the 80s. The supercharger had a clutch pulley that disengaged when turbo boost hit a certain level to and then reingaged when the boost went down. Thre result was almost no lag like a supercharger, but the power continued right into the 8000rpm range. These motors were making in excess of 700hp on motors under 2.5l! The 0-60 time of the ford RS200 was under 3 sec IN THE GRAVEL!!

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Ok I might be wrong, but one of the people that told me that is a mechanical engineer (works at boeing), and another does compressor maps at Garret (my spelling sucks today) they said that the exhaust pulsations would wreak havoc on the turbine wheel and it would not last long. (I was looking at twin turboing my 1980 rabbit with a 2.0 16v that I had built to run pikes peak) Granted I do not have the years of experiance but I do trust my sourses. Oh and with the supercharger I agree about the robing power from the engine but they make more than they take and the boost is instantanious. When you couple them both you get the best of both worlds. In the article in Import Car they said that the trubo picked up where the supercharger left off. The turbo also started to "push" the supercharger internaly and that lessened the drag on the engine at higher speeds.

Gee that's funny, I'm an engineer at Boeing also. There is a difference between an inline 4 and an opposing 4. An inline 4 would split the pulse, but an opposing 4 is like two 2 cylinder engines, each with their own spearate pulse. I was probably one of the first people to twin turbo a small block Chevy (1969), the idea was to use each bank as a 4 cylinder engine. The performance wasn't quite what we expected, but then we didn't know that much about mapping and sizing turbochargers to engines based upon displacement. Heck the first engine we turbo'd used a turbo off of a big diesel CAT engine, as you can imagine, it did little for performance, but we knew we were on to something so we kept looking for smaller turbos. Subaru has been running twin turbocharged 4 cylinders for almost 14 years with no problems, that alone should be enough testimony of the possibility.

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Gee that's funny, I'm an engineer at Boeing also. There is a difference between an inline 4 and an opposing 4. An inline 4 would split the pulse, but an opposing 4 is like two 2 cylinder engines, each with their own spearate pulse. I was probably one of the first people to twin turbo a small block Chevy (1969), the idea was to use each bank as a 4 cylinder engine. The performance wasn't quite what we expected, but then we didn't know that much about mapping and sizing turbochargers to engines based upon displacement. Heck the first engine we turbo'd used a turbo off of a big diesel CAT engine, as you can imagine, it did little for performance, but we knew we were on to something so we kept looking for smaller turbos. Subaru has been running twin turbocharged 4 cylinders for almost 14 years with no problems, that alone should be enough testimony of the possibility.

Ok I stand corrected. (you might know my dad at Boeing his name is George) Like I have said my experiances is with watercooled vw's.

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Will, it's hard to take pictures of a concept. If it were possible, you would have shown us pictures of your proposed 300hp EA82T.

 

here you go.

 

300hp.jpg

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ROFL LOL LOL LOL LOL :lol::lol::lol::lol:

 

 

;)

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