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Anyone running twin precision 6466

Discussion in 'Turbo Cobras' started by 95Cobra_Iowa, Nov 13, 2019.

  1. 95Cobra_Iowa

    95Cobra_Iowa Member Established Member

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    I'm curious if anyone is running these turbos on a 4.6 based cobra engine? What kinda power are you putting down? How's the spool act? I've done a lot of searching and can't get a good answer on these.
     
  2. gimmie11s

    gimmie11s Don’t be an idiot Established Member

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    Those are big turbos that will support over 1500whp.

    They should spool around 4500 rpm depending on which hot side you use.


    Sent from my iPhone using svtperformance.com
     
  3. 95Cobra_Iowa

    95Cobra_Iowa Member Established Member

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    Thanks for the response. I am debating between these turbos and the Gen 2 6266 turbos. If it spools at 4500-5000 I'm probably leaning towards the 6466.

    I'm planning on running 30-32lbs of boost on a 4.6. I worry if I buy the 6266 I'll look to upgrade in a year or two and wish I would've just started with the 6466.
     
  4. FSTMRFR

    FSTMRFR FaST MotheR Fuc keR Established Member

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    I am running the 6466. Are you running manual or auto? They take a while to spool, but make great power. If you plan on street car bangin around town, I would suggest smaller hot wheel
     
  5. 95Cobra_Iowa

    95Cobra_Iowa Member Established Member

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    I'm running a manual now with 61mm precision turbos. I'm running a Sullivan intake and the previous owner had supercharger Cams that aren't well suited to the turbos, so I don't see full boost until 5000rpm. I am switching to turbo cams with a tighter LSA so if I can avoid delaying spool more than what it is now, I'd opt to go big.

    What's the details on yours?
     
  6. FSTMRFR

    FSTMRFR FaST MotheR Fuc keR Established Member

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    The cam profile will change the behavior of your current turbo set up... I would start with that... my opinion...

    I run an auto via TT 5.0 (4.6 base) with large turbo cams. It takes a bit of time to get to full boost, and I don't like it much. I am actually down grading so I get more street fun... that is just the way I want to do it... in a few weeks when I remove the 6266's journal bearing turbos and will send them to precision to get refreshed, then for sale :)

    I am probably going to go with 6062's....
     
  7. 95Cobra_Iowa

    95Cobra_Iowa Member Established Member

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    What's your hp hoal with the 6062s?

    Anyone else? The 6466 seems to be a big turbo and most are running autos from what I can gather.
     
  8. FSTMRFR

    FSTMRFR FaST MotheR Fuc keR Established Member

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    Not really a HP goal. Whatever it makes it makes. My goal is to have it spool quickly and have fun with it.... YOLO
     
  9. 95Cobra_Iowa

    95Cobra_Iowa Member Established Member

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    Bump to see if anyone else has experience with these turbos.
     
  10. tt335ci03cobra

    tt335ci03cobra Well-Known Member Established Member

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    Not running 6466’s, just 62/65’s here.

    T56 with an fr500c cammer intake it made 1208whp on 30psi with stock ecu and 96% fuel trim meaning undrivable dyno tune. I need a stand alone.

    More tellingly, on 10.78psi and pump gas it makes 813whp and on 20psi and 110 octane it makes 1070whp very safely- again I need a stand alone.

    I’m going to step down to 60/62’s when I go stand alone.

    Considering 800whp in the right combo can run 8’s at 150+, I just don’t give a shit about whether my combo can make 1208whp at 30psi or 1162whp or 1177 or whatever the ****.

    Personally, I want to make the most usable power as soon and long as possible.

    I’d like to see 10psi by 3000rpm without break boosting or loading it up. I currently see it by 3500-4000rpm just rolling wot at 2500rpm.

    My power currently looks like this on pump gas and race gas.


    6971D5B9-499E-4450-95D8-86C6FFAF405A.jpeg
    813whp 91 oct gas. Decent spool, great power spread in my opinion from 4500-7500rpm imo.


    29E9AE7D-CC1B-4FE3-95FD-B17926EDB3D1.jpeg
    1208whp racegas with obvious need for a stand-alone vs stock+sct. Too laggy/peaky imo. Honestly good flat power from 6000-7250 though. Like 1200whp for about 1250rpm but it just looks and feels laggy on higher and higher boost.



    Anyways my point is drivability for a street car, and manual, I’m going down to 60/62’s and a stand-alone with a few more tricks to help spool and power production. My numbers in those graphs are with

    • t56 McLeod street twin
    •62/65 comp triplex oil/water turbos (triple ball bearing baby t4 snails)
    •mmr stage 3 custom turbo cams
    •stage 3 ported 5.4L Ford gt/gt500 heads
    •5.3 big bore stroker 9.3/1 compression. Yes it’s that tame.
    •fr500c cammer intake manifold
    •stock computer with sct x4/dyno tuning
    •id1000’s, custom fuel, return twin 405’s
    •custom hot side with CG fab forward headers
    •custom cold side with an inefficient but cool looking dual inlet and dual in/out huge intercooler.

    I’m stepping down to 60/62’s for the slightly better spool, and I figure standalone, wide bands, etc will allow us to do much more to basically make the same peak numbers without the safety concerns and with additional fail safes like knock, retard, etc calibrations. Leaning towards a holly efi setup with digital dash.

    Op’s being 4.6, I couldn’t imagine what 64/66’s would feel like especially with a stick but it would not be very streetable, even with a proper turbo cam imo.

    I rev to 7500rpm, sometimes 8, and I think you’d need all of and then some of 8-9k rpm to find usability with that size pair on a manual 4.6l or have very long gears. I run a 3.73 rear and 26.5” rear tire.
     
  11. 98 svt

    98 svt Premium Member Premium Member Established Member

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    What do you guys use for a trans?
     
  12. 95Cobra_Iowa

    95Cobra_Iowa Member Established Member

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    @tt335ci03cobra I'm jealous of your intake manifold among other things! You've got quite the unique setup.

    I've inherited a setup that was built around 2007.
    8.5 compression 4.6
    Fox Lake CNC Cobra Heads
    Stage 3 crower Supercharger cams (don't help with spool, but they perform well on the top end)
    HPP Turbo kit with old Precision 61MM Turbos (best I can tell these are 670 hp rated old gen turbos from around 2007)
    Sullivan intake with HPP upper
    It was running a returnless fuel system with stock computer.

    I've switched to a Holley Dominator system with a fore return fuel system that gives me room to turn up the boost.
    Once I got this installed and tuned I was able to pump up the boost to 30 PSI, I don't see peak boost to over 5800 RPM and its producing good power at 1065 HP. On 19lbs I see full boost around 5300 RPM

    I've got a new engine being built with turbo cams from @NASVT, and I'm bumping the compression a half point to 9:0 to 1 all in a teksid block setup instead of the iron block I have now. My hope is that with the tweaks I'm making I'll keep spool the same that I have now, and can push the power closer to the 1200-1400HP. Maybe its wishful thinking and I'll end up downsizing to some 6062 turbos for quicker spool and still make 1000-1200hp with quicker spool like you're trying to accomplish.

    I'd be scared to death to run high boost like yours with a stock computer, but obviously its worked for you. I'm jealous of the intake too, from the conversations I have it requires a custom sheet metal intake to run the 5.4 heads if you can't find that intake, so I stuck with the 4.6 based heads on this engine with fox lake CNC, went with bigger valves, and extra hand porting to get some extra flow over what I'm doing now. With all that work, it would still be better off with GT500 heads.

    @98 svt I'm running a t56 with a Mcleod setup like @tt335ci03cobra for a manual transmission. I'm not launching at a track on slicks, so I haven't had any issues with it to this point.
     

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  13. tt335ci03cobra

    tt335ci03cobra Well-Known Member Established Member

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    Thanks for the compliments, I am fortunate to know a great local builder who can handle the hassles and intricate stuff/time/and pressing on when it gets complicated. Adapt this, relocate that, set this, adjust that etc.

    Great pick on the stand alone, I feel it’s one of the best. You have the right idea to get a proper cam/valves/springs etc in to optimize airflow where the turbos want it.

    You have all the intake volume you’ll need, I’d honestly say go smaller on the turbo unless you are in a competitive racing series or environment where you need 1400whp.

    Your intake manifold setup will carry air well to 8000rpm and the aggressive turbo cam will help make power there. A fresh set of 60/62’s on a t4 housing, 30-35psi, and a full custom 3” hotside should move plenty of air. 1200whp is easily doable, I’ve seen 1070whp on a terminator 4.6 on 27psi through stage 1-2 c heads and 61’s through a t56 and stock sct tuned ecu 7000rpm setup. You’d have more manifold, and more rpm than he had. He also had a milder cam, something like a stage 1 turbo cam.

    1000rpm matters if you have a Sullivan and stage 3 cam.

    Obviously stage is a bullshit term, the important thing to do is specify what you’re doing with the car, prioritize the most prevalent function of the car, and steer the cam profile, turbo size, and project that direction.

    Example, I’m now stepping to smaller turbos because in 5,000 miles, I’ve ran 11psi or higher all of 3-5 hours worth and maybe 25-100 miles. I street drive it. My pump gas setup is really good, I just want a bit more low end bite.

    In a properly setup 3500lbs car on a drag pack (slicks/skinnies), 800whp is 150mph trap speed and 1.25-1.5 60ft motivation depending suspension etc.

    The honest truth is even on 1070whp and 20psi, I have to be in 3rd around 70mph to do a mostly wot pull. 4th over 100 it’ll hook every time.

    1200-1400whp is entirely a back half as in after the 8th mile number. It’ll take you from trapping 150 to trapping 175-190 if it’s setup well and handles heat well, but otherwise it’ll just blow tires and parts.

    Personally, I want to get my pump gas tune running 8.9-9.5 @150+ with the irs/t56 reliably before calibrating for higher boost setups again. I figure learning what it needs to run there will then allow me to just use boost by gear after to add what power we can on e85 or racegas for crazier trap speeds and slightly quicker et’s. 60’ is where I’ll lag, tops I bet we can find is a 1.39-1.45, but we will probably be consistently in the 1.5’s which is a bottle neck for et’s.

    That all said, mines a street car 99% of its life, so I’m totally fine. I’d much rather have it optimized for the street and hooking well there, keep my mostly handling suspension, 13 or 14” brakes etc. For a drag build, I’d go 67’s, 9000rpm, sra, gut it, and punch for 7’s.
     
  14. tt335ci03cobra

    tt335ci03cobra Well-Known Member Established Member

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    The great thing with the 4.6 that you have is it’s thick, reliable, and stays cooler.

    Lots of meat between cylinders, and surface for head gaskets to seal up tightly.

    Yes, running a gt head is great and unshrouds the valve, but the 5.3 actually heavily compromises long term longevity. Big bore strokers live short lives.

    If I keep the mod architecture after this mill, I plan to build an e85/98 only 11/1 4.3-4.5L sleeved and destroked 9000rpm. I’ll likely have a variant of a voodoo esc build done though with a cpc, 4.9-5.0L displacement restoring some wall thickness with sleeves, etc.
     
  15. 95Cobra_Iowa

    95Cobra_Iowa Member Established Member

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    I'm sure you are right on the turbo setup. I'm probably chasing a number on it with the turbos. The bad news is they are sitting in my garage right now new in the box, so I don't want to take a hit reselling them. My driving habits are probably pretty similar to yours where the vast majority of the driving will be done on the street and its not safe on high boost with this car on the street. I'm normally running about 15lbs and 700 hp which is a lot of fun driving around with this car. I refuse to put a cage in it to take it to the track.

    I'm heard a lot of bad things with the boss engine with high boost, so obviously your work has paid off keeping it together with those thin walls. It sounds like you said the Teksid 4.6 with thicker aluminum sleeves works better than most options on the 4.6 setup.

    That potential engine build you speak of sounds like a ton of fun. I would imagine that you would be screaming at 9000 rpm with that setup. I've been drooling over the idea of a turbo voodoo setup with that high rpm in a stick car. Would be tons of fun!
     
  16. badcobra

    badcobra It's Fast Established Member

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    Just run what you got man. The 6466's are some badass turbos and the car will be very strong. With the Holley, you can ramp boost and also set up some wheel speed sensors for traction control to be able to run all the boost when you want to. I can put down 1300+ on the street and stick it. And it feels plenty safe to me because the power is controlled and the car is stable. One thing I would consider is to just start planning to put a MVB auto in it and the fun factor will increase 10 fold and the car will be significantly faster. I too am 100% street car.

    You guys are talking smaller turbos, I just bought some 6870's and will be shooting for 1500+ here soon. My 6766's are for sale if anyone is interested!

    6870's :):)
    U2kEXb8l.jpg
     
  17. 95Cobra_Iowa

    95Cobra_Iowa Member Established Member

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    This guy is going to 6870s! That is going to be a handful. How much boost are you going to run and how high are you going to spin it?

    Finishline is putting together my engine now, which should be able to hold up to a little more abuse that my current iron block setup. I know I should go to a mvb automatic, but I can't bring myself to do that quite yet. I'm running the Holley system like you, why did you go with the wheel speed sensor setup versus the driveshaft sensor? That is above my head, but I have a tuner that would be able to set it up for me that I've done work with in the past.
     
  18. badcobra

    badcobra It's Fast Established Member

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    I have no idea how much boost. I've run 35+ psi before on the street so we'll see! Hopefully at 35psi, it's making 1500. I had a bent camshaft which ate a couple cam journals so I had to send the head to BES in Indiana to put some cam bearings in. While the heads were out, I had some additional porting work done which showed big improvements, especially on the exhaust side. I also have a new 6" Garrett intercooler being built as my Bell 4.5" core one was not efficient enough. Finish Line also refreshed my shortblock with a slight hone and some new pistons so everything is fresh.

    As for the wheel speed sensors, it was easy to do because the sensors read off the ABS rings. My tuner just made some simple mounts for em. Setting this up completely transformed how the car works on the street. I used to blow the tires off at 100+ mph and the car would be all over the road, now it's just straight down broadway every time, just an amazing difference!

    Excited to see you get that engine and get it in the car. The fun is just beginning!
     
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  19. 95Cobra_Iowa

    95Cobra_Iowa Member Established Member

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    I need to make the switch to traction control. It is definitely on the dangerous side with the power it makes on the street without it. The idea of having some control over that with the Holley sounds like a great option.

    I'd be interested in seeing flow data on your heads. I just got mine done at fox lake with oversized valves and cleaning up the intake by hand after the CNC portion. I have attached my flow sheet from Fox Lake here. This is as far as they go. I know that BES has a good reputation, I didn't realize they did Modular stuff.
     

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  20. badcobra

    badcobra It's Fast Established Member

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    Head flow is very close! The exhaust numbers will be different because Fox Lake used a pipe, that adds about 30 cfm. My heads were ported by a friend many years ago, he did a nice job, but it needed some professional attention and he was able to make some significant gains on them so I am very pleased. Janderson Heads in MN is who did the work for me.

    Intake
    cClu254l.jpg

    Exhaust
    ey01NMal.jpg
     

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