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  1. #1

    Question Small engines with huge turbos?

    Hey import owners, this is an honest question I am hoping I can get some info on. How come everywhere I look, I see guys with very small engines (1.8L-2.4L) putting on HUGE turbos, often times bigger than the "600HP capable" PT51 "T3-family" (?) unit I have on my 4.3L Syclone? I managed to get this 3650# behemoth down the track in 12.2 seconds with the stock TD06-17C turbo at 20 PSI Boost. Why would a lighter weight import with a smaller engine need a bigger turbo to run similar or lesser times?

    I would say that I have relatively poor throttle response on my truck, even with a 2600 converter it's quite a bit less responsive than the stock turbo was with the stock 2100 RPM converter. Basically if you want to go fast, you've pretty much got to hold the pedal down.

    I'm looking at turbos for a little street project I'm considering on 3 Liter engine, and the ones I'm considering virtually all fall in a range much smaller than the turbos I see all the imports talking about (20G, GT35R, GT40+ etc.). My understanding was, on a street car you want a turbo that's going to give you good response and good part throttle boost and quick spool over the small gains in top end you might get with a gigantic unit and huge exhaust housing.

    With these imports I'm wondering how the response is, does the engine basically function like an "on/off switch"? Do you guys get any boost at low RPM or part throttle? What is that like to drive around?

    My thought on what would be the most fun to drive around would be a huge big block with loads of instant throttle response, the whole small engine, high RPM, huge turbo thing seems like the polar opposite of that.

    I have "zero" import experience so I'm hoping some of you guys can clue me in (and maybe I can take notes for my little project too.) Thanks!!
    Josh
    91 GMC Syclone, full street trim, full accessories, stock bottom end.
    11.45 @ 117.7 57mm PT51 turbo at 20 PSI, 93 octane street tune w/alcohol injection. D.I.Y. Budget build, <$4500 under the hood complete.


  2. #2
    Brumbrabrabra!! nismodave's Avatar
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    Well my car does not make huge #s. Around 400 to da wheels at 19 psi.

    I dont get full boost until 4200 and I redline at 7700.

    I enjoy driving my car on the street all the time. I think if I go bigger on the Turbo it will lose alot of streetability.

    Unlike alot of the other import guys here in SE WI, 1/4 mile times are not the only thing I shoot for. I sure enjoy my reliability and streetablity with my setup.

  3. #3
    Quote Originally Posted by Syclone0044
    I managed to get this 3650# behemoth down the track in 12.2 seconds with the stock TD06-17C turbo at 20 PSI Boost. Why would a lighter weight import with a smaller engine need a bigger turbo to run similar or lesser times?
    Stock block(small) + stock 14b(smaller) + fwd dsm(light weight) = 10.841@126.63(20 psi/no N2O)

    1/4 Time 10.841
    1/4 MPH 126.63
    1/8 Time 6.966
    1/8 MPH 101.83
    60' 1.579

    www.dsmtimes.org
    Last edited by Teufelhunden; 11-28-2005 at 07:32 PM.

  4. #4
    Quote Originally Posted by MoparScott
    Stock block(small) + stock 14b(smaller) + fwd dsm(light weight) = 10.841@126.63(20 psi/no N2O)

    1/4 Time 10.841
    1/4 MPH 126.63
    1/8 Time 6.966
    1/8 MPH 101.83
    60' 1.579

    www.dsmtimes.org
    OK, that didn't really prove anything. A list of the top 100 fastest cars with a 14b turbo on a mass produced car versus my results? The car you cited seems to be about 1 second and 10 MPH faster than the next closest candidate, so there's obviously an incredibly major detail missing from the story there. My comment (that you quoted) referred to my results, implying comparison to local guys like me and their results with their DSMs.
    Josh
    91 GMC Syclone, full street trim, full accessories, stock bottom end.
    11.45 @ 117.7 57mm PT51 turbo at 20 PSI, 93 octane street tune w/alcohol injection. D.I.Y. Budget build, <$4500 under the hood complete.


  5. #5
    Wasn't trying to prove anything or really help . Tuning is always the biggest factor, as you know.

  6. #6
    Senior Member..now yer posting!
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    Quote Originally Posted by nismodave
    Well my car does not make huge #s. Around 400 to da wheels at 19 psi.

    I dont get full boost until 4200 and I redline at 7700.

    I enjoy driving my car on the street all the time. I think if I go bigger on the Turbo it will lose alot of streetability.

    Unlike alot of the other import guys here in SE WI, 1/4 mile times are not the only thing I shoot for. I sure enjoy my reliability and streetablity with my setup.

    Good god, full boost at 4200???? thats some lag oops I mean preperation time. I can hit full boost at damn near 3200.

    Syclone- you also have to look at how much air the turbo pushes also. Say on a 16g at 20psi feels great, but on a 35r at 12-13 psi feels like the same thing. Although the larger turbo seems like it takes forever to spool you are still making a lot of power because the turbo is moving A LOT more air. The 16g I am running has been heavily ported on the cold side and massaged on the hot side with a larger outlet 10.5 vs 9.8 housings. This set-up is going to be pitched in 3 weeks and moving onto a stroker and larger turbo, most likely a 35r, maybe even a 40 (space limits me) Here is a video of AMS's evo still with a 2.0 and a 42r. http://media.ams-evo8.com/amsonthestreet.wmv

    And here are some pics of the set-up:



    Oh and also full boost isn't really a good way to determine the turbos capabilities.
    03 Evo. 6262/2.0
    518hp/ 24psi/ 94%IDC

  7. #7
    number1
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    That DSM is the fastest 14b powered car in the nation. That car doesn't have anything in it, I bet it ways 1500 pounds. And I agree with you syclone, most imports run big turbos because they think that is the only way to have a faster car. In fact running a smaller turbo that can spool and give the car more area under the curve would net better gains.

  8. #8
    Subaru Guru fireguyrick's Avatar
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    2.5ltr with a Gt35r .82 AR

    I actually like the drivability with this setup over the stock setup. Sure, I do not see the full 22psi of boost till ~4krpm, but I get better MPG because it is easier to stay out of boost. Though, with the short gearing of the STi it is VERY easy to get into boost by just downshifting.

    Rick

  9. #9
    Ol' School Russ Jerome's Avatar
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    Quote Originally Posted by EvolvedRegal
    you also have to look at how much air the turbo pushes also. Say on a 16g at 20psi feels great, but on a 35r at 12-13 psi feels like the same thing. Although the larger turbo seems like it takes forever to spool you are still making a lot of power because the turbo is moving A LOT more air. .
    Agreed, 20psi of cooler flowing air will beat the same setup overspooling
    and heating 25psi thru an undersized turbo. The new family's of GT35 and
    the like turbo's are light years ahead of the old Turbonetics wheels that
    were designed in the 50's. My old design Turbonetics 60E is at full boost
    by 3800, same setup with a GT35 is fully spooled by 3100 in a little 2.2.

    My 60E fullsize with a stage 3, .63 exaust is not huge by definition but
    will support well in excess of what I will ever put to it. It's a blast to
    drive on street even tho I am automatic, no smoky burnout just feels
    like a rubberband until tires ignite shifting to second
    http://sites.google.com/site/russjerome/
    Watching the country collapse in front of me while nobody else notices...

  10. #10
    When you get rid of the Stock sycolne turbo ill buy it from you...

    Why not upgrade to the "20G" wheel???

  11. #11
    ProjectCamaro.com ProjectCamaro's Avatar
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    I always wondered the same thing. I use to be into imports and all the turbo kits seemed to come with the 16G turbo which is WAY to big for a stock 1.6 or 1.8 liter.
    RedLS1.com
    Because You Can Never Modify To Many Camaro's

  12. #12
    SNATCH A KISS ORVICEVERSA Junky Giorgio's Avatar
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    Quote Originally Posted by ProjectCamaro
    I always wondered the same thing. I use to be into imports and all the turbo kits seemed to come with the 16G turbo which is WAY to big for a stock 1.6 or 1.8 liter.
    oh wow... where the heck have you been. "forced induction; the replacement for displacement"
    TRIUMPH DAYTONA 675 TRIPLE
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    Thanks to YellowWagon for the pics and JunkGSX for the ladies.
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    junk, your junking my thread.

  13. #13
    I wanna go fast... $title Champion Crawlin's Avatar
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    aren't you still in the 13's? so i'd say that it really didn't replace my displacement

  14. #14
    He is nowhere right now
    2007 Lexus LS460
    2013 Toyota Tundra Rock Warrior
    2011 Toyota Camry SE V6

  15. #15
    I wanna go fast... $title Champion Crawlin's Avatar
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    yeah i know, i got an oil trail out my garage and down my driveway and onto the street leading me to where he is hahaha

    i'm just ******* with ya Junk, my **** ain't going anywhere either

  16. #16
    Quote Originally Posted by nismodave
    Well my car does not make huge #s. Around 400 to da wheels at 19 psi.

    I dont get full boost until 4200 and I redline at 7700.
    What turbo(s)[?] are you running now? I was just browsing some Nissan forums last week searching for turbo information by coincidence

    EvolvedRegal and Russ Jerome: I've heard the same thing repeated all the time, and in my experience it's just not true (or the effect is grossly overexaggerated.) The stock turbo compressor maps on my truck suggested I would have "low effeciency" and "excessively heated air charge" the further I got beyond 14 PSI boost, yet I continued to experience gains as I turned it up all the way to 20-21 PSI. (no gains beyond that.) Furthermore, I then upgraded from the 550cfm stock Mitsu TD06-17c/8cm2 turbo with 2.5" stock crimp-bend downpipe to a PTE Buick-style "PT51" 950cfm turbo with a huge .86 A/R turbine housing and T350 exhaust wheel and a big 3" mandel downpipe, and guess what? NO FASTER AT THE SAME BOOST! The difference was downright negligble. At 15-18 PSI there was no gain whatsoever, and much slower spool. At 19-20 PSI Perhaps 1 tenth 1MPH. The only REAL gains were the higher boost range this turbo could operate at (20-25+ PSI). In other words, I would put money on my truck with the stock turbo at 20 PSI "hot air, out of efficiency" versus the big PT51 at 15 PSI "flowing much more air" any day. The difference is obvious by seat of the pants.

    In my opinion, you'll only get REAL gains (the kind worth paying money for) if your existing turbo is an extreme bottleneck (for instance a stock turbo on a vehicle with upgraded heads/cam, or poorly sized stock turbo from the factory), or you plan on running higher boost than you ever could run (efficiently) before. If someone ran significantly faster at the same boost merely by upgrading their turbo (and not falling into any of the categories I already covered), I'd be interested to learn about it.

    Quote Originally Posted by number1
    most imports run big turbos because they think that is the only way to have a faster car. In fact running a smaller turbo that can spool and give the car more area under the curve would net better gains.
    I have to agree with you 100% Not to mention a lot more fun to drive!

    Berettaspeed: I already upgraded the turbo, but I'm going to hang onto my stock one for now. It needs to be rebuilt anyways.

    In summary, my thoughts are to not waste money on a bigger turbo until you've completely outgrown the one you have. That has worked well for me and saved me some cash to boot. In fact I think the best turbo for a street car is the smallest turbo you can get away with and still make great power.
    Last edited by Syclone0044; 11-29-2005 at 10:56 AM.
    Josh
    91 GMC Syclone, full street trim, full accessories, stock bottom end.
    11.45 @ 117.7 57mm PT51 turbo at 20 PSI, 93 octane street tune w/alcohol injection. D.I.Y. Budget build, <$4500 under the hood complete.


  17. #17
    Formerly known as Yellow Wagon jbiscuit's Avatar
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    Quote Originally Posted by Syclone0044
    I think the best turbo for a street car is the smallest turbo you can get away with and still make great power.
    my wagon is a perfect example of that. I have literally maximized every bolt on mod possible without cheanging out the turbo or factory boost control solenoid and tried to keep the car a fun, reliable daily driver. I have done that. The car does VERY well from a roll (not an AWD subaru's strong point), a dig etc

    The car isn't the fastest subaru around or even on this board for that matter but it does OK. Several people have been in the car and were impressed with its performance. After all, it is just a station wagon.
    Last edited by jbiscuit; 11-29-2005 at 10:54 AM.
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  18. #18
    Yeah J, I think there's a lot to be said about streetability and driveability that DOESN'T show up in peak horsepower/torque numbers, or even ET/MPH numbers. The whole "area under the curve" thing, part throttle boost, etc. Two cars can run the same time at the track but one can "feel" a ton faster on the street and be more fun to drive. Dennis "95 TA" has a lot to say on this subject as he's gone to great lengths in that regard, with his car. (Too bad he doesnt post anymore )
    Josh
    91 GMC Syclone, full street trim, full accessories, stock bottom end.
    11.45 @ 117.7 57mm PT51 turbo at 20 PSI, 93 octane street tune w/alcohol injection. D.I.Y. Budget build, <$4500 under the hood complete.


  19. #19
    Formerly known as Yellow Wagon jbiscuit's Avatar
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    well said. A street car to me should retain daily drivabilty features. It should be able to idle in rush hour. It should have space for groceries. It should be able to run on pump gas and in august in 80% humidity you should have air. Thats all part of making a car fun. My car is a friggin dog on the A/C but it still retains it in case I need it.

    here is my formula for the ultimate daily driver street car set up:

    AWD
    turbo 4cyl
    larger displacement (2.2L or above)
    manual trans (5 or 6 speed)
    stock flywheel for driveability
    turbo that runs around 18-20psi on pump gas...around 280-300awhp ±
    factory-style EM (reflash etc)
    A/C intact
    power window/locks
    CD player with decent stereo
    must be able to hold 2 sets of golf clubs
    all seat belts intact
    no roll cage (IMO that is not factory so it shouldn't be present)
    suspension mods (adjustable coilover suspension/sway bars)
    all season radials
    aluminum wheels
    brake upgrade

    thats the basic formula I think would make a good daily driven fun car. With a competent driver, the car will go 12's all day, tear up on ramps and snow storms. You will have a BLAST in the snow and still be able to haul the groceries and golf clubs
    Last edited by jbiscuit; 11-29-2005 at 12:14 PM.
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  20. #20
    Formerly known as Yellow Wagon jbiscuit's Avatar
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    by the way, riding in a 300whp AWD car is VERY fun...
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