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+--- Thread: Twins? (/showthread.php?tid=1245)
Twins? - Jtn190D - 03-29-2010
Hi all, so I've been thinking that it might be a good idea to put twins on my engine. So the question is whats the difference between twins and compound turbo's? And what size turbos would work well on my om602 engine? The reason i don't want VNT/VGT turbo is because it seems to hard. I think this would work good with bigger eliments to?
Answers Will be nice!
Thanks
Justin N.
RE: Twins? - Kiwibacon - 03-29-2010
You want to do twin turbos because VGT turbos seem too hard?
It's a whole lot easier to fit one turbo than two. Less than half the work.
RE: Twins? - ForcedInduction - 03-29-2010
Compounds has a large turbo pressurizing the air fed into a smaller turbo. The small turbo multiplies the pressure ratio.
Compounds require a lot of trial and error to match correctly and aren't needed unless you need 35-75psi of boost. Running lower that will be less efficient than a single turbo.
Twin turbos can mean either sequential or parallel.
Sequential has two of the same turbos (or one small and one big) but only one working until a certain RPM range. Very difficult to time and extremely difficult to do without computer control.
Parallel turbos are pretty pointless on anything but V engines. They simply split the workload between two turbos. Slightly less efficient due to two sets of bearings causing drag instead of one and a much larger heat loss surface area.
Compounds don't make much sense on anything less than 400hp. The finns make over 500hp with just 30psi of boost.
RE: Twins? - Deni - 03-30-2010
Is there a wastegated turo, like the Garret GT model, that can give enough air to about 300 HP, yet spool as fast (or slow) as the stock TB25 turbo the om602 has?
RE: Twins? - Jtn190D - 03-30-2010
I wanted to do twins because they would spool fast yet there would be a big turbo for high RPM high horsepower.
I don't think i would have a problem with a VNT except it's still not clear how it works or how to do it? And if it's so easy why don't more poeple do it?
I didn't realize it would be that hard to do twins ether.
I just want more power out of my engine!!!
RE: Twins? - Deni - 03-30-2010
The easiest, but not the best, solution I know of controlling a VNT is by installing an actuator connected directly to the vane position and controlled the same as a wastegated turbo.
When there's no boost vanes are in closed, max boost position.
As boost increases, the actuator arm will start to move the vanes, thus slowing down boost increase, until the vanes are at fully open position.
This solution doesn't offer the benefit of a VNT while cruising, that is to have the vanes at open position so that there will be minimal exhaust brake thus better economy.
(03-30-2010, 07:54 AM)Jtn190D I wanted to do twins because they would spool fast yet there would be a big turbo for high RPM high horsepower.
I don't think i would have a problem with a VNT except it's still not clear how it works or how to do it? And if it's so easy why don't more poeple do it?
I didn't realize it would be that hard to do twins ether.
I just want more power out of my engine!!!
RE: Twins? - Jtn190D - 03-30-2010
What's the best then?
Would there be a manual way of adjusting when you want to?
RE: Twins? - Deni - 03-30-2010
(03-30-2010, 09:44 AM)Jtn190D What's the best then?
Would there be a manual way of adjusting when you want to?
Well, best would be the electronic controlled one, where vanes are set based on throttle position, speed, load, altitude, IAT etc
RE: Twins? - muuris - 04-02-2010
(03-30-2010, 07:54 AM)Jtn190D I don't think i would have a problem with a VNT except it's still not clear how it works or how to do it?
Are you serious?
If you don't know how it works, you can't possibly predict the difficulties involved.(03-30-2010, 07:54 AM)Jtn190D And if it's so easy why don't more poeple do it?
Why don't more people build 605/606 engines, why to stick with 615/616/617... it's really not that hard, but one has to let go of the wastegate-thing. VNT is not a wastegate, it's a variable size exhaust housing. On light load it's a large housing, to let exhaust flow freely. On acceleration, it goes to minimal (momentarily) to peak EGP and get the boost rising, then enlarges to set a good EGP/boost balance and finally to control the boost. Not a wastegate, but a turbine housing so large that the boost just won't build anymore (as in big diesel duty engines).
Learn stuff. Read a book or two. Or just buy a car with a more powerful engine
RE: Twins? - Tymbrymi - 04-05-2010
(04-02-2010, 01:23 PM)muuris Why don't more people build 605/606 engines, why to stick with 615/616/617...
Most of us don't have the budget you guys do (the people who have the money aren't into MB's), and those style engines are very rare. The 605 was never imported into the US, and the turbo 606 was only imported in 1998 and '99.
I'm slowly working on my 606 project, but I don't have all that much money to spend on it. I did just buy a complete (pedal cluster, linkages, etc) W124 5-speed though!!
RE: Twins? - Jtn190D - 04-05-2010
Guys were not talking about om606 om605 engines if you wanna talk about those engines start a new page. this page is about the om602.
And this site is to swap info and help people out. And learn!
Its not that i don't know how a VNT works i'm not sure the the controllers work.
If the 7.5 elements work what will be the best over all turbo for my car? Not VNT.
RE: Twins? - George3soccer - 04-05-2010
put a hx35, for a lighter power source, or put a hx40, and call it a day. simple as that. cheap simple..
RE: Twins? - ForcedInduction - 04-05-2010
HX40 is overkill even on 606 engines. HX35 will work but it will spool like crap on a 602 unless you revv the nuts off of it or pump a lot of fuel (black smoke) to get it spinning.
An HX/HY30, HY35 or HE341 are a much more sensible choice.
RE: Twins? - Deni - 04-06-2010
(04-05-2010, 08:31 PM)ForcedInduction An HX/HY30, HY35 or HE341 are a much more sensible choice.
What cars are these turbos used on?
Do any european cars use these turbos?
Any special keyword I should use on ebay as very few show up?
Which of these turbos would be "perfect" for 200 - 250hp on the om602?
Cheers
Deni
RE: Twins? - ForcedInduction - 04-06-2010
(04-06-2010, 01:32 AM)Deni What cars are these turbos used on?They are only used on Cummins engines.
Quote:Do any european cars use these turbos?No cars use Holset turbos.
Quote:Which of these turbos would be "perfect" for 200 - 250hp on the om602?Any of them, but the HY35 and HE341 will have more overhead room while the HX/HY30 will make the car daily drivable.
RE: Twins? - Deni - 04-06-2010
(04-06-2010, 01:39 AM)ForcedInduction(04-06-2010, 01:32 AM)Deni What cars are these turbos used on?They are only used on Cummins engines.
Which cummins engine, or truck, was the HX/HY30 used in.
Thanks
Deni
RE: Twins? - ForcedInduction - 04-06-2010
It was an option on the 4BT, 4BTA, 4BTAA and ISB3.9. Rare though.
RE: Twins? - Jtn190D - 04-06-2010
Thanks for the info Forced.