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Opinions on Turbo Option


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The holset's are used alot in Sweden on Volvo's and bimmers.

Alot of information on http://www.savarturbo.se but in sweedish though. haha

 

I'm gonna use a HX40 on my rb25det. It's pretty big and heavy so I might cut of some parts on the exhaust housing to reduce the weight.

 

There is a Audi 1.8l turbo with a HX35/40 here in Norway that's doing pretty good. Not sure about spoolup though.

 

 

Here are some old pics I have:

 

Exhaust housing: 8.2 kg = 18lb !

eksosdel-Holset.jpg

 

 

Holmedal920.jpg

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lemme know how that goes, the hx35 is still on my passenger floor board. it's a pretty heavy bastard lol. mine has a dsm flange on it so it'd be some unnecessary modifications to get it on my t3 flange'd exhaust mani. plus i think the turbo's sweet spot is above my motor's. definately though lemme know what you think when you try it.

 

this is a great forum =]

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The ONLY reason a larger turbo would flow at 14psi what a smaller one is flowing at 20psi is because of the reduced restriction on the exhaust side, and improve flow into the head because of it. And if thats the case (and assumes lots about head/cam setup) guess what, you have just completely altered the spool characteristics: larger turbine = slower spool.

 

There is no perfect solution, only compromises.

 

If you want more power at the same boost, head work head work head work. A friend of mine went from 590hp @ 1.8 bar (RB30ET + GT3582R 1.06 A/R turbine), to 590hp @ 1.2 bar with head mods: reshaped inlet port, 1mm OS valves, additional 20deg 0.05 duration cam). Then made 650hp @ 1.8 bar with the poor GT35R completely maxed out.

 

Good luck,

 

Dave

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The gt3076 isn't going to make much more power at the same boost pressure. You're looking at the same turbine wheel, so backpressure isn't going to be much better. Unless your gt3071r is completely maxed out at 20psi, your not going to gain much by going to the gt3076r. Atleast step up to a larger turbine housing when your going to the gt3076.

 

Justin

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The gt3076 isn't going to make much more power at the same boost pressure. You're looking at the same turbine wheel, so backpressure isn't going to be much better. Unless your gt3071r is completely maxed out at 20psi, your not going to gain much by going to the gt3076r. Atleast step up to a larger turbine housing when your going to the gt3076.

 

Justin

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i finally got in touch with my buddy with a 35r on his rb25. he said 20psi around 4k-4.2k , built bottom end but stock head/cams/and even stock intake manifold, he made 500rwhp/420tq @ 19psi on pump gas, then he got the greddy intake, and pon cams and made 560rwhp@24psi on race gas. the 35r doesn't sound too big now =]

 

kick ass @ thehelix112 =] , ya 30/76 not enough. amen, and headwork is later, right now gotta throw a bigger turbo at the equation and situmawate my drivetrain....you'll see in a sec

 

as far as the gtk500....on an l28, i think you'll be fine and you'll make some good numbers 450ish is my guess. msg me when you get it on there and tuned. i wanna see ur graph.

 

i broke my "new" rb20 tranny on the way home from work today rolling into third gear. soon as it hit 20 psi my tranny said "gdflkdjfggkjhiurggjigjfijfg" i don't know why i did but i was on the side of the interstate and i called my tuner....he picked me up and my car on his trailer. on the way home he tells me to open up this box, and in it is his frankenstein turbo to try out. i see the exhaust side first.....

hmmmm .63 a/r ok....it's temp coated....sweet, i turn it over, daaaaaaaayuuum!! dats a big ass compressor housing...on it said gt4082r 68 trim...i think it's a .72 a/r compressor housing. i have no clue how that joker's gonna fit but by golley we're gonna pop that big summabich on there GIT R DUNN! lol

 

i'll let yall know how it goes.......on a side note.....anyone ever put an s13 rear subframe in an s30??? and can i put my rb20 front bellhousing on a z32 tranny and be good to go? once i redo my driveshaft that i just got back and installed before leaving work with some nice REMOVEABLE ford u-joints and a thicker / balanced shaft AHHHHHHHHHHHHHHH. *sigh

 

i love you guys lol

Dave =]

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If you want more power at the same boost, head work head work head work. A friend of mine went from 590hp @ 1.8 bar (RB30ET + GT3582R 1.06 A/R turbine), to 590hp @ 1.2 bar with head mods: reshaped inlet port, 1mm OS valves, additional 20deg 0.05 duration cam). Then made 650hp @ 1.8 bar with the poor GT35R completely maxed out.

 

Aye, the boost only represent the amont of air that the engine wont eat.

Pretty different numbers on thoose two.

 

Wonder if I should get my head ported when I have it apart...

So darn expencive.

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And not make as much power. Smaller inducer on the 4082, and less flow (~58 vs ~62lb/min).

 

There is nothing stopping you from running a divided manifold on the GT3582R, in fact I do. The primary benefit is in stopping the pulses from opposing `halves' of the engine from inteferring with one another. You can also extend the divider in the manifold into the turbine housing and taper it down to a point.

 

GT4082R looks like a big waste of time to me. GT4088R now... Although I have heard rumours that the GT35R is one of the old turbine housings using the high nickel metal: `` Turbine housing is cast from high-nickel "Ni-Resist" material for extreme applications''. Probably not important for street apps though.

 

 

Dave

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Not True. The gt3082r is a big mismatch. It spools about like the gt35r, but doesn't make the power. You'd think that going to small turbine wheel would give you the best of both worlds. The small turbine wheel can't generate the axial forces necessary to efficiently move the larger compressor wheel.

 

Wouldnt this be the same senario as the gt4088 cold side? It is the same exact cold side housing, right? Both are close to .70 cold side.

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the guy who lent me the hx35 says hx35 is waaaaaaay better than the hy35

 

does he have any idea as to what kind of power these things are capable of? i've never seen a dyno sheet or anything as far as power outputs from an hx35...plus i don't know how to reaad compressor maps so i'm kind of fresh out as far as that goes.

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so what was the consensus on the hx35? with the better head design of the rb over the L how close does anyone think it will perform compared to the hy35 on an L28

 

HX is the new design and HY is the old style.

Like garrett BB and old journal bearing.

 

I did some reading on a honda forum where they experiment with Holset.

http://www.honda-tech.com/zerothread?id=1225182&postid=28266977

 

Some good reading there, but wrong engines :)

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