What to do what to do.......
Postmaster
Joined: Aug 2010
Posts: 2,554
Likes: 9
From: Northern Arizona
Maybe I am seriously missing something here... But the 4bt and 6bt CTD's that I've read up on need quite a bit of work to put out 500 horses. Again, I'm not a cummins guy, I dont know what those modifications cost, or how it compares to building up an IDI, but it's not like you can grab a running drop-in out of a bread truck and get high performance out of it.
One of the key points you name as a plus for the Cummins is fuel mileage, but I am skeptical that a CTD vs. an IDI in the same truck would be much different. If an IDI in a light 2wd F150 can get 30-ish mpg... seems they are quite efficient for their displacement, and our big, heavy, high profile, often 4x4 F250's and F350's are simply limited by aerodynamics, weight and driveline friction. The physics of wind drag and acceleration of mass will not be any easier for a Cummins.
Both engines are good choices, I suppose, so it boils down to preference more than anything, but building the IDI cuts out the cost and effort of adapting the CTD. Given the availability of killer parts from Racin', to me the choice is obvious.
One of the key points you name as a plus for the Cummins is fuel mileage, but I am skeptical that a CTD vs. an IDI in the same truck would be much different. If an IDI in a light 2wd F150 can get 30-ish mpg... seems they are quite efficient for their displacement, and our big, heavy, high profile, often 4x4 F250's and F350's are simply limited by aerodynamics, weight and driveline friction. The physics of wind drag and acceleration of mass will not be any easier for a Cummins.
Both engines are good choices, I suppose, so it boils down to preference more than anything, but building the IDI cuts out the cost and effort of adapting the CTD. Given the availability of killer parts from Racin', to me the choice is obvious.
Posting Guru
Joined: Feb 2013
Posts: 1,203
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I have a tuff time seeing a little 4bt with 500 horse
I am a fan of both mainly because they aren't eletroninc
They are both bubba tuff and will run for ever
I don't know if the performance cummis parts last as long as stock or not
But idis need new injection system every 100,000 or when your fuel milage gose south witch is 1000 bucks witch you may not have when you have kids
This is just my brother's stock cummis but it got 16-18 back in 1990 and it still gets that today and the engain has never been touched. It recently got a flatbed because the box fell apart, but that can be expected of a Dodge
I am a fan of both mainly because they aren't eletroninc
They are both bubba tuff and will run for ever
I don't know if the performance cummis parts last as long as stock or not
But idis need new injection system every 100,000 or when your fuel milage gose south witch is 1000 bucks witch you may not have when you have kids
This is just my brother's stock cummis but it got 16-18 back in 1990 and it still gets that today and the engain has never been touched. It recently got a flatbed because the box fell apart, but that can be expected of a Dodge
Thread Starter
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Senior User
Joined: Mar 2013
Posts: 274
Likes: 0
From: aouth east idaho
500hp isn't to bad to reach in a 4bt. Hell south bend has a 700+hp one in their mud rail you can look it up. But I wouldn't ever go that high. Peeps are regularly driving around 400hp ones but I think I will stick with the idi. I just really want to push one.
Thread Starter
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Senior User
Joined: Mar 2013
Posts: 274
Likes: 0
From: aouth east idaho
If its ppumped turn up fuel some injectors and crank up boost= 400ho easy. Basically same as a 12v from what I understand. Any more than that you need to start studding and doing supporting mods. Get on cummins forums and look around you'll see what I'm talking about. 4bt swaps is another good one. Probably would cost about the same as an idi to get 400 maybe a bit more. I haven't done the math on just mods.
Lead Driver
Joined: Apr 2008
Posts: 6,945
Likes: 13
100hp / liter pretty up there for a diesel 400hp 4bt would be the equivelant of a 600hp 6bt.. and they take alot more than cranking the fuel and injectors to get there let alone reliable. 300hp is about the limit of a 12v with just "turnin it up" so says diesel power. To get more than that you start spending $$ turbo(s) IC, sticks, pump, studs, not sure if the bottom end really needs anything cummins are not within my realm of familiarity. I know they call em cummaparts for a reason. Nothing is bulletproof. Anyway, i guess what my speil amounts to is 400hp seems like alot to ask of a 4bt, when you can build a 400hp 6bt that will get more or less the same fuel economy and be twice as reliable with half the work. However, for 400hp i still think you would be cheaper and just as reliable with the IDI. Just my .02 and what little knowledge i have on the subject.
Red: Not sure where you get your pumps man, but you can get a quality 90cc pump and new sticks too for under $750
Red: Not sure where you get your pumps man, but you can get a quality 90cc pump and new sticks too for under $750
Thread Starter
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Senior User
Joined: Mar 2013
Posts: 274
Likes: 0
From: aouth east idaho
New question. Northern auto parts has a rebuild kit for 1300 anybody know much about these? Seems legit but I dunno
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Posting Guru
Joined: Feb 2013
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R&D Is the cheapest place I can find them them its' close to 800 plus shipping ehtier way unless your breaking the bank after you have kids it can be tuff to find and extra 100.
I should have asked how long he planing on keeping the truck, He did sound like he wanted kids, just not right now
I should have asked how long he planing on keeping the truck, He did sound like he wanted kids, just not right now
Posting Guru
Joined: Feb 2013
Posts: 1,203
Likes: 0
R&D has ip and injectoers, I would go with the idi, I would bet that a hopped up idi would out last your 400 horse 4bt
Postmaster
Joined: Dec 2004
Posts: 2,941
Likes: 32
From: Maple Valley, WA
Yes Northern sells a rebuild kit, and from what I have heard, they are decent kits with decent well known common brands. When I do my 6.9, Ill probably do a northern kit, I have ordered from them before for other engines, and I liked what I got.