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Need some opinions on building a turbo motor

Discussion in 'Turbo Cobras' started by Dimitri318, Aug 18, 2018.

  1. Dimitri318

    Dimitri318 Well-Known Member Premium Member Established Member

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    So the motor out of my Mystichrome lost compression so I pulled the motor and tranny and sold it for $6,000 so I have a good down payment to start putting together a longblock for my twin turbo build. I called L&M and they are putting together a quote for me for the complete longblock. I called a very reputable tuner in Georgia and they told me not to go with L&M bc they could put together a motor just as good for cheaper. I told them i wanted a 4.6 with Oliver rods and probably gibtec pistons but they wanted to do a 5.0 boss block bc it would make an extra 30 or so torque to help spool the turbos faster. The also recommended DSS internals and a set of their custom cams but wanted to keep the stock compression. I told them I wanted to bump the compression up to 9.5:1 or even 10.5:1but they said it would be better in the long run for stock compression bc it would be easier to replace turbos from turning up the boost instead of replacing motors from the high compression. I was gonna use them for the build and the tune but I’m having second thoughts now.

    My question is who would you guys use to build a complete longblock if it were you? The car is gonna get a hellion twin turbo kit on it and is a convertible so it wouldn’t see much track use and I’m putting a tremec Magnum in it. I live 3 miles from my restaurant so it wouldn’t exactly be a daily driver but if I do drive it, I’d maybe be driving 10 miles a day. I’ve heard nothing but good things about L&M so that’s why I was considering them for the build but what are your guys opinions?
     
  2. DSG2003Mach1

    DSG2003Mach1 Well-Known Member Premium Member Established Member

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    hard for anyone to help with no fuel type or power goals. Also check out MPR in south Florida
     
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  3. cobranick01

    cobranick01 New Member Established Member

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    Sounds like you had a better idea than the shop. I would let Micheal at L&M put something together way before using a boss block with dss internals. And as for compression, that would depend on what fuel you use

    Sent from my SM-G955U using Tapatalk
     
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  4. Dimitri318

    Dimitri318 Well-Known Member Premium Member Established Member

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    Sorry I have a complete lvl 4 Fore innovation triple 465 pumps return style system that I’m planning on running E85 on. And my power goals are 1,000hp but will drive around on 6-700hp.
     
  5. cobranick01

    cobranick01 New Member Established Member

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    10.5 to 1 compression for sure.

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  6. Dimitri318

    Dimitri318 Well-Known Member Premium Member Established Member

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    That’s what I was thinking. I saw @badcobra ’s build and he made me wanna bump the compression up and go twins instead of a big single lol. And I’ve heard of DSS being good for the old pushrod motors but everything I’ve read about them in our 4.6’s, the reviews aren’t that great. I’m gonna give MPR a call too and see what they quote me also.
     
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  7. 98 Saleen Cobra

    98 Saleen Cobra Authorized Vendor Authorized Vendor

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    LOL at the shop saying they could build you the same degree engine as L&M with a boss block, low compression, and DSS internals ahahaha. Stay the **** away from them, matter of fact don't even let them tune it.
     
  8. cobranick01

    cobranick01 New Member Established Member

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    Mpr builds some badass stuff too. My last build way back in 2005 had 8.7 compression and was lazy. Im currently at 10.8 with the new motor. And with a Borg Warner 8596 it made 1232whp at 25 psi thru a th400. I highly suggest the higher compression with e85. And as 98 saleen cobra said, don't even let them tune it. Sounds like they don't have a full understanding of what works with these motors

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  9. Dimitri318

    Dimitri318 Well-Known Member Premium Member Established Member

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    @98 Saleen Cobra Yea that’s what I was thinking when he said a boss with DSS internals would be just as good as an L&M motor, I was gonna ask him if we were talking about the same L&M lol.

    @cobranick01 i used to have a zinc yellow vert with a 76mm hellion on it but was a stock bottom end and it felt lazy. That’s why I wanted to raise the compression and keep the 4:6 but the guy was adamant about going with the 5.0 boss and keeping stock compression. The bad thing is that he is one of the biggest names down here in tuning but I don’t want to blast them on the forums so I don’t wanna say who it was
     
  10. cobranick01

    cobranick01 New Member Established Member

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    I wouldn't blast them either. But with e85 as your fuel choice I see no reason to run low comp and up the boost to make the number. I would much rather up the comp and use a lower boost setting. You will have much better off boost throttle response. And from what I have seen throughout the years is boss blocks having head gasket sealing issues. There are way too many 4.6l rolling around making a 1000hp and being very reliable. Plus the cost of buying a boss block when you can have a teksid for 3-400 bucks. As for dss..... I live about 30 mins from there and also have been around a lot of top racers in this area that either don't use them or stopped using them

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  11. 98 Saleen Cobra

    98 Saleen Cobra Authorized Vendor Authorized Vendor

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    fwiw, I had a Boss block 8:5 compression pump gas engine.. It was cool. Made 670 on 17psi and race gas.. 98 Cobra cams, stock 04 cobra heads..

    New engine
    10:1 compression, custom cams, ported heads.. 16psi on E85 it made 910rwhp.. That's low boost and not a turbo a Centri instead.. If I had a turbo on 16psi I'd be well into the 1k rwhp on low boost.. Something to think about.
     
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  12. Nightmare302

    Nightmare302 OhChuteRacing Owner Established Member

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    MPR is a great shop.

    Don't look past Molnar rods instead of the olivers.
     
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  13. badcobra

    badcobra It's Fast Established Member

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    If it were me, I would just duplicate my build :)
     
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  14. 98 svt

    98 svt Premium Member Premium Member Established Member

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    I'm with him.^^^^^
     
  15. slo984now

    slo984now AKA 01yellerCobra Established Member

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    Some builders just can't get away from the old school thinking as far as boost and compression. A few years ago I was looking for a decent machine shop for my Teksid set up. I went to one shop on the recommendation of a friend. They built both his brother's and his 347's. I was talking to the head guy and told him I planned on running 9:5 compression. He straight up told me I couldn't do that on the street. I should add they were mostly push rod motor type guys.
     
    Last edited: Oct 2, 2018
  16. Over8oosted

    Over8oosted Member Established Member

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    I went with l&m on my build, pretty pricey however only thing i could salvage were the crank and heads. Went with a boss 5.0 block, ported heads, studded all, 9.5:1 comp, everything else was custom spec’d by Michael. Build took him 4 months, bill was quite a bit higher then the original estimate but he worked with me alittle. Twin 67’s, 26spline t56, irs she made 1090/897 21# 15degrees all on 93 pump. Engine spins to 7200, stock ecu. Been through the trans 2 times since its been together, def need a magnum or built auto. Stock 4.6 blocks are no longer avail new thats the reasoning behind the 5.0 block. at the time (nov 16’) when i had the motor built, Mike had 2 4.6 cast blocks left and that was it he couldnt get anymore. Overall im very happy with the engine, i have zero fear of engine failure.
     
  17. Dimitri318

    Dimitri318 Well-Known Member Premium Member Established Member

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    You sir, are one of the main reasons I decided to go twins instead of a big single lol. I’m starting to piece together the build so I might PM you if I need some help if that’s cool??


    That’s one of the reasons I want to go with L&M is bc I would have piece of mind. On the other hand, if I replicate @badcobra ’s build, I would come out cheaper but I really don’t trust the machine shops around here so I’m kind of stuck in a bind.
     
  18. Dimitri318

    Dimitri318 Well-Known Member Premium Member Established Member

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    So I ended up getting a really great deal on a hellion 76mm turbo kit with MM k member, coilovers, cobra intake, and pretty much everything to put a complete motor together. It is a stock 03 iron block, rods, crank, 4 thread heads, everything except pistons bc the ring lands collapsed on the dyno so I have to order new ones. My original plan was to make close to 1,000hp but that is gonna have to wait until I save the money to do it the right way and not cheap out on any parts so that’s not gonna happen for awhile sometime down the road.

    So I pretty much got all the motor stuff for around $1,500 and would just need to order pistons to put it back together and be happy with 700hp. But my dilemma is that my motor builder said I should go ahead and do a few things for insurance like accident secondary chain, etc. but as we’ll know, wants I start buying one thing, it’s snowballs and before I know it, I’ll be all least $5,000 into buying little things here and there.

    I honestly wanna just buy some decent pistons and put it back together to drive and be happy with 700hp. Would there be anything that you guys would REALLY recommend I do while I have it apart just to be safe? Would raising the compression on a pretty much stock motor be pushing it? Or should I just kept the compression 8.5:1 so I don’t over do it? I have a fore triple pump return style E85 fuel system that I’ll be running on the car as well.
     
  19. slo984now

    slo984now AKA 01yellerCobra Established Member

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    My biggest recommendation is be patient. If you have a goal work towards that. Don't build something 3/4's of the way. You'll just end up wishing you had done stuff different and end up pulling it all apart again to fix it. And then you're out more time and money because you're doing it again.

    Either way I wouldn't run it at the 8.5:1. If you're going to run it on E85 I'd definitely bump the compression up.
     
  20. KEVINS

    KEVINS Well-Known Member Established Member

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    Just an FYI on the iron Cobra Blocks. They are not as durable as the aluminum Teksid blocks. After some long discussions on another forum people thought that my 900hp through a 4R70 would be doable w/o hurting anything since it's a turbo car but other people have broke them with less hp. Usually manual trans cars with blowers seem to hurt the blocks. With 900hp and being a street car that doesn't get pushed all the time I think it will be fine. What will 1000hp do? I duno..

    So when going for 1000hp just keep this in mind.

    Some reading that may explain some issues:
    Where is the boundary for the factory block...?
    ks
     
    Last edited: Oct 12, 2018

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