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Thread: Turbo selection for a 5.7 V8

  1. #1
    Attempting a thing... J's Avatar
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    Turbo selection for a 5.7 V8

    Want:
    The low spools
    The low boosts

    Do not want:
    The 1,000 horse powers
    The max boosts at max RPMs


    Something that spools at idle and hits 6 PSI between 1500-2000RPM on the LS1 would be purrrfect. If it starts to run out of huff by 5 or 6 grand that's fine. I just want the torques.

    I'm thinking:
    • T76 - nothing fancy, just oil cooled
    • T4 flange
    • Compressor a/r around 0.8, with inducer 75mm, exducer 100mm or so
    • Turbine a/r around 0.7, Inducer 65mm, exducer 75mm
    • Simple journel bearing job will do
    • V-band if I can afford it



    I'm worried I've either gone too far and it'll be cracking 6 PSI at idle, or not far enough and it'll be a big, laggy piece of shit.

    Can any guru's here offer their 2c? Will this do the job for something nice and responsive?

  2. #2
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    GT35 off an XR6T?

  3. #3
    infantile egomaniac CussCuss's Avatar
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    Would a precision 67/66 journal do the job about the same but with a modern design? Lots of A/R options.
    this signature intentionally left blank

  4. #4
    Attempting a thing... J's Avatar
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    I hadn't quite got as far as brands or part numbers yet.

    I was more wondering if my choice of AR's and inducer/exducer sizes were on the money for what I was after in terms of 6 PSI up to 5 or 6 grand, super responsive.

    Even my flange choice was a bit uncertain. Lots of people say for the LS engines it's gotta be T6, but that just seems like overkill for what I need.
    Last edited by J; 05-04-16 at 04:13 PM.

  5. #5
    Wanker MexicanBatman's Avatar
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    i know nothing about turbos

    but my G6E made 14psi @ 2200rpm

    and thats a 4L, so id say with that turbo you'll easily bend your rods @ 2000rpm
    ..........

  6. #6
    Attempting a thing... J's Avatar
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    Quote Originally Posted by MexicanBatman View Post
    and thats a 4L, so id say with that turbo you'll easily bend your rods @ 2000rpm
    Exactly this.
    Running massive boost at idle is a real worry, so I want it to be responsive but if i go too far it'll just go bang.

  7. #7
    Registered User 2rismo's Avatar
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    Pte 6870
    Quote Originally Posted by piss98
    I wish Kochie would get blown out to sea and never found, in fact most of those dumb cunts standing in the rain telling people not to stand in the rain need to get fucked. Stupid tart on the news last night talking to the weather guy "wow you look totally drenched there whateverthefuckhisnamewas." No shit you vapid bitch he is standing in a fucking cyclone.

  8. #8
    Attempting a thing... J's Avatar
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    Quote Originally Posted by 2rismo View Post
    Pte 6870
    Yeah, my budget is more like
    http://www.ebay.com.au/itm/291380351...%3AMEBIDX%3AIT

    Only the best for my LS1.

  9. #9
    Scaramouch seedyrom's Avatar
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    Had a GT35/40r then swapped to a T04z.


    For the money, the 35/40r was great.

    T6 flange not necessary.

  10. #10
    [DIRTY31] lysdexia's Avatar
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    with your vague idea of what you want, 1.06 GT35/40 is my immediate thought.
    HR31 Coupe - RB20, Bilsteins, Cage and shit
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  11. #11
    Attempting a thing... J's Avatar
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    You don't think 1.06 is too large?

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    Quote Originally Posted by J View Post
    You don't think 1.06 is too large?
    1.06 GT3582R is what Ford put on a BA/BF 4L. Will be on full boost sub 2500rpm, and good for mid 400rwkw figures.

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    2x 3582s on a 5.7 was a animal by 3000 so 1 would be on way early

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    Quote Originally Posted by J View Post
    You don't think 1.06 is too large?
    1.06 on a GT35 turbine is very different to a 1.06 on a GT55 or GT12 turbine.
    Quote Originally Posted by Bosshoggett View Post
    If your planing to drive this on the road and enjoy it, id suggest a second opinion, someone with a history in Australian Rally or Fink River . If your just playing dyno comps. Then ok

  15. #15
    sack riding 10sec rx7's Avatar
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    Quote Originally Posted by vsute1998 View Post
    2x 3582s on a 5.7 was a animal by 3000 so 1 would be on way early
    this...
    im a cunt
    and apparently i dont know shit...

  16. #16
    Registered User dnegative's Avatar
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    Maybe two 3076's?
    The old GT3582 works well enough on a 2JZ, fuck knows what its like with an extra 2.7L and two cylinders but its going to be too small
    Quote Originally Posted by cracka View Post
    Fuck I'm retarded

  17. #17
    Registered User I'm DJ!'s Avatar
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    Quote Originally Posted by 67rce View Post
    1.06 GT3582R is what Ford put on a BA/BF 4L. Will be on full boost sub 2500rpm, and good for mid 400rwkw figures.
    I reckon this is too small, 4088 on 3.4litre on boost at 3000rpm, which is pretty much all the time, all over by 7000... Or to4z.

    Gmmad on here has a 351 truck, can't remember what turbo but is on boost off almost idle, find his thread...
    DJ's don't need sigs

  18. #18
    sack riding 10sec rx7's Avatar
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    i had 2x 2876 on my ute 8 years ago, made 750rwhp on a stock engine at 17psi.. was no lag but would have made a lot more power with 3076's
    im a cunt
    and apparently i dont know shit...

  19. #19
    Arrogant wankeler Slides's Avatar
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    Quote Originally Posted by J View Post

    I'm thinking:
    • T76 - nothing fancy, just oil cooled
    • T4 flange
    • Compressor a/r around 0.8, with inducer 75mm, exducer 100mm or so
    • Turbine a/r around 0.7, Inducer 65mm, exducer 75mm
    • Simple journel bearing job will do
    • V-band if I can afford it


    You have described a compressor that flows way more air than you need with a P-trim turbine. The T76 should really be coupled with a Q trim turbine. Even a GT3788R (these are very good bang for buck, same price as a 35R) with the largest turbine option is a bit small on an LS1, even aiming for really low spool, it is only about 7% bigger than a 35R the turbine is basically P-trim size, probably still too small. If you like the response of a 35R on the ford 4L or want it a bit more snappy down low a GT4094R will probably still be significantly more responsive in the LS1 than the turbo barra motors.

  20. #20
    Registered User dnegative's Avatar
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    GT4202 for a single?
    The 4088 doesnt look like its overly suitable based on its compressor map, looks a tad small.
    Quote Originally Posted by cracka View Post
    Fuck I'm retarded

  21. #21
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    4088, it is a tad small if you want to make 800hp. It's perfect if you want to make 500 and be happy with that. 1.19 hot T4 and it would be fairly savage.

    4202 is probably ideal if it's a tight stock auto, 4294 if manual. Go up a turbine size with appropriate converter.

    But all commodores make "600 aspirated, not even on the bottle" so it's irrelevant.
    Quote Originally Posted by Bosshoggett View Post
    If your planing to drive this on the road and enjoy it, id suggest a second opinion, someone with a history in Australian Rally or Fink River . If your just playing dyno comps. Then ok

  22. #22
    Attempting a thing... J's Avatar
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    Quote Originally Posted by Slides View Post
    You have described a compressor that flows way more air than you need with a P-trim turbine. The T76 should really be coupled with a Q trim turbine.
    Thanks for the feedback Slides. So are you saying I should go slightly smaller on the compressor wheel, maybe down around 67-71mm range instead of the 75-100 I had initially?
    If I did that and left the turbine at 65-75mm, how do you think it would perform on the LS?

    And thanks for everyone else's input too. Here is a bit more info on what's involved to answer some of the questions:
    • Gotta be single turbo. It's for an engine swap, so space is extremely limited. Barely room for one turbo, let alone two.
    • Transmission is auto, not manual.
    • As far as power in concerned, the car is pretty light so I'm not chasing huge power here. I'd be stoked with 500 horses. Well aware you can get this NA on the LS, but this is the way I want to go.


    Let's just assume for the minute we're locked into the choice of a T76 turbo with a T4 flange. While this isn't entirely true, it would be ideally suited with my current space, parts and fabrication limitations.
    What compressor and turbine wheel choices can you guys recommend to fit?
    Last edited by J; 06-04-16 at 12:42 AM.

  23. #23
    Attempting a thing... J's Avatar
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    Quote Originally Posted by seedyrom View Post
    Had a GT35/40r then swapped to a T04z.


    For the money, the 35/40r was great.

    T6 flange not necessary.
    Do you remember what the turbine specs on the T04z were and when boost came on?

  24. #24
    Arrogant wankeler Slides's Avatar
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    If you are limiting yourself to P trim turbine go the biggest housing you can. You don't need more than 70mm compressor inducer.

    Do you already have something lined up or just familiar with that size turbo? Looking at Chinese copies of the older garrett stuff for cheap?

    I note dale (10secrx7) will have the most real world experience with this stuff but he is ideologically opposed to "small" turbos on any given engine which is probably why he didn't just say use XYZ, end thread. The gt4202 is closest equivalent single to the twin 2876s dale mentioned.
    Last edited by Slides; 06-04-16 at 01:15 AM.

  25. #25
    Attempting a thing... J's Avatar
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    Quote Originally Posted by I'm DJ! View Post
    Gmmad on here has a 351 truck, can't remember what turbo but is on boost off almost idle, find his thread...
    Thanks for the tip DJ. I just went and looked up the build thread then.

    He started with a gt3576 1.05 housing, and apparently the boost was "instant".
    Then switched to a GT4088 and got 300kw at the rears.
    Vid here:



    Looks like it hits full boost between 2-3 grand and carries it to redline with HEAPS to spare. So that's probably a bit bigger than what I want.
    I think it's an oldschool 393 stroker engine (could be wrong). If so, that means it probably flows similar air to the LS1 so should be a fair comparison.

    Unfortunately I couldn't find any info on what his compressor & turbine specs were though.

  26. #26
    Arrogant wankeler Slides's Avatar
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    Sounds like you are talking yourself into a gt3788 if new garrett or T66 if China copy. I'd still probably err to 1.15 or 1.32ar turbine housing rather than tight ones for cheap the T66 or the largest option on gt37.
    Last edited by Slides; 06-04-16 at 01:27 AM.

  27. #27
    Attempting a thing... J's Avatar
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    Quote Originally Posted by Slides View Post
    If you are limiting yourself to P trim turbine go the biggest housing you can. You don't need more than 70mm compressor inducer.

    Do you already have something lined up or just familiar with that size turbo? Looking at Chinese copies of the older garrett stuff for cheap?

    I note dale (10secrx7) will have the most real world experience with this stuff but he is ideologically opposed to "small" turbos on any given engine which is probably why he didn't just say use XYZ, end thread.
    Pretty much on the money there, yeah - I'm looking at Chinese knockoff's of old turbo tech. I have a small amount of experience with these nasty little Chinese turbos, and generally they seem to fail at medium to high boost levels. This is the other reason for me wanting to keep this as a low boost application. I've seen these Chinese T76's run at low boost for 40,000+ kms (with track & drag abuse) and never miss a beat. And then I've seen them wound up to 20 psi and fail within minutes. I guess it's just a familiarity thing for me when it comes to the T76 as a choice (and price, obviously). The water & oil cooled Chinese turbos seem to be more prone to failure. Seeing as the T76's are just oil cooled, it's one less thing to go wrong on them. Plus it means less plumbing in my engine bay too, which is nice. It's already going to be a damn plumbing nightmare in there.

    I mean, look at this thing, for example:
    http://www.ebay.com.au/itm/T76-T4-tu...cAAOSwPhdU3MHB
    it's under $380 brand now, with vbands.
    Compressor:
    a/r : 0.80
    inlet:4"
    out:2.5"
    In:76.7mm
    EX:102mm
    Turbine:
    a/r : 0.96
    IN:64.5mm
    EX:74.5mm
    Flange: t4

    I could buy two or three of them for half the cost of a genuine unit, and where I'm looking at positioning the turbo it would take me 5-10 mins to change them in the event of failure. Worst case I'll be plucking turbine out of my cat or compressor out of my intercooler. But at the boost levels I'll be running that's fairly unlikely.

    The bottom line is I absolutely love cars but I don't earn a lot of money. I'll be doing most of the fab work myself and I'm just trying to do the best I can with my budget. There's always going to be a better way to do these things, I know. I just want to have a bit of fun with what I can afford. Yeah, it might blow up - and maybe one day I'll be able to afford to put the best gear into my car. But today is not that day

  28. #28
    Attempting a thing... J's Avatar
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    Quote Originally Posted by Slides View Post
    Sounds like you are talking yourself into a gt3788 if new garrett or T66 if China copy. I'd still probably err to 1.15 or 1.32ar turbine housing rather than tight ones for cheap the T66 or the largest option on gt37.
    Yeah I guess so, providing my assumptions so far are correct anyways!
    are the T76 and Gt40 series turbo's more or less the same frame size? Meaning the T66 = GT35?
    Last edited by J; 06-04-16 at 02:08 AM.

  29. #29
    Arrogant wankeler Slides's Avatar
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    The P-trim turbine that should be coupled with T66 (and is used with the"T76" you posted) is almost exactly the same size as gt37. But I am though that garrett didn't sell anything bigger than T70 or at least T72 with P-trim turbine but maybe you just chose mix and match compressor/turbine, the exhaust manifold pressure required to drive the larger compressor at decent boost would take half the benefit of the larger compressor flow away. I think the Q-trim turbine wheel was closer to gt42 but it has been a while since i have seen the measurements. The tighter O-trim was probably more like gt30 or a more open gt28 turbine in flow despite still having the same major diameter as P-trim, so no real classic equivalent to gt35. T04b 58?mm compressor inducer and P-trim turbine. Slower response and less total compressor flow. Or T62 compressor, i think that was a thing?

    I know there are plenty of sellers doing T66 so you should be able to get one cheap as you don't need the extra air of the T76 but if that is all you can find at that price point it should work well enough at the flow you want, not trying to break records.
    Last edited by Slides; 06-04-16 at 09:02 AM.

  30. #30
    sack riding 10sec rx7's Avatar
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    Quote Originally Posted by Slides View Post
    I note dale (10secrx7) will have the most real world experience with this stuff but he is ideologically opposed to "small" turbos on any given engine which is probably why he didn't just say use XYZ, end thread. The gt4202 is closest equivalent single to the twin 2876s dale mentioned.
    hes been told but didn't want to listen. GT35 with 1.06 but seems to think the housing is too big for a fucking 5.7L v8.. put 2 of the cunts on it and it will still choke the engine..

    PTE6870 is the perfect turbo for a single. the turbine flows heaps better than a GT35 and it will make a lot more power on less boost
    Last edited by 10sec rx7; 06-04-16 at 09:07 AM.
    im a cunt
    and apparently i dont know shit...

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