Author Topic: Bottom end, Crank, Rods, and pistons. Best way to go for performance???  (Read 4876 times)

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Offline sharpxmen

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Re: Bottom end, Crank, Rods, and pistons. Best way to go for performance???
« Reply #15 on: August 18, 2010, 12:36:05 AM »
I had one built by 505 performance, it has ross racing pistons and rods, bored and balanced crank, cam, shaved head, port polish, valve job, roller rockers, and the compression is dropped cause its a turbo motor but he tells me it will hold up to about 15 pounds of boost for daily driving and should be close to 450hp but we will see i still am working on it. but it can be done

4 cyl 2.5L with 15psi of boost = 450HP? or a 4.0?

what compression did they set it for?

EDIT: i ran the MSD calculator and this is what it came to on the 150cu.in./2.5L for 450HP at the crank
BSFC: put it at 0.57 since it's a turbo
87% VE (for the rpm below i think it's a fair guestimate)
AFR: 12
boost:15psi
inlet air temp: 70F
intercooler efficiency: 70%
CFM: 715
injectors (4): 72lb/hr
required RPM: 10,000 => 458HP

so it is possible if you can spin it to 10k rpm.
« Last Edit: August 18, 2010, 12:49:45 AM by sharpxmen »
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Re: Bottom end, Crank, Rods, and pistons. Best way to go for performance???
« Reply #16 on: August 18, 2010, 01:57:32 PM »
I honestly dont know what the compression is but i know from what he tells me it should run pretty good, and the 450# thats from him but i know it will spank most 4.0's

Offline sharpxmen

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Re: Bottom end, Crank, Rods, and pistons. Best way to go for performance???
« Reply #17 on: August 18, 2010, 02:25:38 PM »
I'm sure if 505 build it will be a monster, just dunno with the hydraulic flat tappet cam if you can spin it that high, can't see it making that power at 6000 rpm (doesn't add up as far as CFM requirement to generate that amount of power) - i ran the same calculations for 6000 rpm and put in 100% VE (just to see what comes to, not real world), the calculated HP at the crank is 316, at 7000 rpm is 369HP and at 8000 is 421. If you drop the VE to 95 for example then you get 300/350/400 at 6/7/8000 rpm. I'd really be interested to see how much it makes though, sounds like a great build - any pics of it yet? or did they give you a list of parts with part numbers they used, that would be great if you can post them just for reference.
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
Latest: Corbeau BajaRS heated seats :dance: keeping warm the rear end

Offline stan98tj

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Re: Bottom end, Crank, Rods, and pistons. Best way to go for performance???
« Reply #18 on: August 18, 2010, 06:00:34 PM »
I'm all for this! From the moment i got the 4banger all my jeep buddies have been telling me to swap out the 4cyl for the 6 or "throw a v8 in there" My response is...everyone does that. all their suggestions did was harden my resolve to build a badass 4cyl jeep once i had the money. Recently ive been leaning towards a 4cyl diesel swap..it'll still be a diesel lol. But when the time comes to choose, it will be between building up the current engine till it spanks the 6cyls or getting a 4cyl diesel that also spanks the 6cyls. Anyway, i can see where you're coming from on this.
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D-money

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Re: Bottom end, Crank, Rods, and pistons. Best way to go for performance???
« Reply #19 on: August 19, 2010, 03:53:26 PM »
i wanted to do the 4bt cause im all about doing somthing differant, but im only 20 and my wallet told me to stay with what i had already, so i decided to build it to the max, ill try to take pics tomarrow cause it should be running by then, and since i dont have a dyno near by i doubt i will dyno it in the near future, but from what zak tells me it will be badazz, but ill keep you posted he has only built three of these motors so i have to play with injectors, and make a fuel map. But man i am excited.

Offline Jeffy

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Re: Bottom end, Crank, Rods, and pistons. Best way to go for performance???
« Reply #20 on: August 19, 2010, 05:44:20 PM »
i wanted to do the 4bt cause im all about doing somthing differant, but im only 20 and my wallet told me to stay with what i had already, so i decided to build it to the max, ill try to take pics tomarrow cause it should be running by then, and since i dont have a dyno near by i doubt i will dyno it in the near future, but from what zak tells me it will be badazz, but ill keep you posted he has only built three of these motors so i have to play with injectors, and make a fuel map. But man i am excited.
4BT isn't 'different'.  It's actually a fairly common swap.

I know 505 Performance did the turbo swap in Pete Trasborg's 2.5L.
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Re: Bottom end, Crank, Rods, and pistons. Best way to go for performance???
« Reply #21 on: August 23, 2010, 01:56:11 AM »
I finally got it running it runs pretty good timing is still a little off but ill keep you updated.

D-money

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Re: Bottom end, Crank, Rods, and pistons. Best way to go for performance???
« Reply #22 on: August 23, 2010, 09:54:39 PM »
I need some advice i got the exhaust done today, but it sounded terrible so i took it home and pulled the plugs and the first three looked good then i got to the back one and it was like the cylinder was dead, so i replaced the plugs and all the wires, but still the same thing the only other thing i can think of is the injector isnt squirting enough fuel or a flat lobe of the cam. Any Ideas i need some help on this one. thanks