Max boost idit
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Max boost idit
Posted this up on fb haven't heard anything. But what is the general consensus on max boost for idit connecting rods? I have read 40 and 50. What about if you want the motor to last?
build sheet
7.3 rebuilt pistons, rings bearings studs torque cam.
rotating assembly fully balanced with turbo rods
thanks
looking just for some quick thoughts and opinions with all the new turbos and kits out there now trying to make a decision
build sheet
7.3 rebuilt pistons, rings bearings studs torque cam.
rotating assembly fully balanced with turbo rods
thanks
looking just for some quick thoughts and opinions with all the new turbos and kits out there now trying to make a decision
Logistics Pro
Joined: Jun 2017
Posts: 3,978
Likes: 514
From: Edmond, OK
40-50 
Check out these numbers:
https://www.ford-trucks.com/forums/8...l-idi-n-a.html
The consensus seems to be 10-15 with head studs.
Check out these numbers:
https://www.ford-trucks.com/forums/8...l-idi-n-a.html
The consensus seems to be 10-15 with head studs.
Laughing Gas
Joined: Dec 2013
Posts: 884
Likes: 7
Anything past ~20 and there is no answer. There simply hasn't been enough documented builds past that threshold to say. Ballpark of 40-50 and you are in the danger zone, even then that's based on one build on one set of rods.
Who knows, if you want reliability I suggest stay under 30.
Who knows, if you want reliability I suggest stay under 30.
Postmaster
Joined: Dec 2011
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Yup, and remember, it's not the boost pressure that bends rods, it's the (much) higher cylinder pressures that burning a greater quantity of fuel with that added air that does it.
You could run 40 psi of boost without more fuel than N/A and it wouldn't make any difference bending rods wise(Of course, actually making that boost might be hard...)
Now, 15-20 PSI of boost, at the 200-250RWHP level is something that can be done without head studs for a longer period of time(at least a year) without blowing head gaskets. Beyond that, well, not sure. I don't have something beyond 250, so I can't say.
You could run 40 psi of boost without more fuel than N/A and it wouldn't make any difference bending rods wise(Of course, actually making that boost might be hard...)
Now, 15-20 PSI of boost, at the 200-250RWHP level is something that can be done without head studs for a longer period of time(at least a year) without blowing head gaskets. Beyond that, well, not sure. I don't have something beyond 250, so I can't say.
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Lead Driver
Joined: Apr 2008
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Stock turbo rods probably 400-450rwhp and expect them to last and do any work with them. Justin thinks that might be conservative, and he didnt bend the NA rods till over 400 so he may have a point. I put psd rods in mine because i want to tow a 2 car enclosed trailer with tools and parts (and i couldnt find an IDIT and knew where a siezed psd was for cheap). Only running a 110cc for now, but i have the room to go 150 on my current turbo. First things first, i would chose a different cam, the torque cam is great NA, and with mild boost pressure seen with stock pumps and turbos, but when you really want to flow some air its going to hold you back, and i suspect be pretty warm. How the horsepower translates to boost is irrelevant, compression, cam, turbo, up pipes, exhaust, timing, and more will affect the boost numbers. From the few setups running in the 400-450rwhp range, most are seeing between 40-55psi, but, that number doesnt mean jack to the rods. Its an indicator of potential cylinder pressure, but its all relevant.
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Stock turbo rods probably 400-450rwhp and expect them to last and do any work with them. Justin thinks that might be conservative, and he didnt bend the NA rods till over 400 so he may have a point. I put psd rods in mine because i want to tow a 2 car enclosed trailer with tools and parts (and i couldnt find an IDIT and knew where a siezed psd was for cheap). Only running a 110cc for now, but i have the room to go 150 on my current turbo. First things first, i would chose a different cam, the torque cam is great NA, and with mild boost pressure seen with stock pumps and turbos, but when you really want to flow some air its going to hold you back, and i suspect be pretty warm. How the horsepower translates to boost is irrelevant, compression, cam, turbo, up pipes, exhaust, timing, and more will affect the boost numbers. From the few setups running in the 400-450rwhp range, most are seeing between 40-55psi, but, that number doesnt mean jack to the rods. Its an indicator of potential cylinder pressure, but its all relevant.
pretty well put thanks and good luck with yours.
I choose the torque cam for a few reasons.
one I'm putting all of it in a bronco so less weight to move
in also plan on doing some crawling and low speed stuff through deserts and rock and such so top end goes out the window
we push sprint cars with ours rigs, so that extra grunt from the torque definitely helps it get moving, another win for the torque cam
finally I'm gonna be running 3.55 for gears so this thing can get out and stretch on the freeway, and I read somewhere long ago that was another deciding factor for this cam. Not saying Justin's is worst but I think my selection was better suited for my needs.
also I think with the added pressure it will help spool the large turbo, but I'm gonna run a large external wastegate on the crossover pipe to keep the boost and drive pressures down.
thoughts? ??
Lead Driver
Joined: Apr 2008
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I assume you mean pressure from the cam, but its the wrong pressure, if i understand correctly, that cam causes more reversion, than the stock one, and maybe even justins though he has more duration. The reason why is the torque cam has the stock intake and longer duration exhaust, IE, more overlap. This is why it helps NA. Justins cam has more lift / duration, but he widens the LSA and retards the intake valve opening. That is why i said hot with the torque cam and that much boost. Drive pressure is always higher than boost to some degree, with a cam that has any overlap, youre basically creating an EGR, without the benefit of a cooler. If you size your turbo decently, you dont need a wastegate, unless youre going compounds or something. All a wastegate does is "waste" energy that the turbine cant efficiently use due to too small of housing, or too small of turbine. Youre better off non gated, with proper sizing. If youre sized well, spool up will be a non issue, i hit over 20 in about 1.5 seconds with my 362
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I assume you mean pressure from the cam, but its the wrong pressure, if i understand correctly, that cam causes more reversion, than the stock one, and maybe even justins though he has more duration. The reason why is the torque cam has the stock intake and longer duration exhaust, IE, more overlap. This is why it helps NA. Justins cam has more lift / duration, but he widens the LSA and retards the intake valve opening. That is why i said hot with the torque cam and that much boost. Drive pressure is always higher than boost to some degree, with a cam that has any overlap, youre basically creating an EGR, without the benefit of a cooler. If you size your turbo decently, you dont need a wastegate, unless youre going compounds or something. All a wastegate does is "waste" energy that the turbine cant efficiently use due to too small of housing, or too small of turbine. Youre better off non gated, with proper sizing. If youre sized well, spool up will be a non issue, i hit over 20 in about 1.5 seconds with my 362
im gonna run a 362 as well. How do you like? Street manners and such.
I'm gonna stick with this cam. I seem to think lift and durations is not that great of a change. Not like a huge lift of a gasser cam on a big block like on my fe.
you might be right and I'll have to change it later, but it's in there now.
really like to hear about your s300???
thanks
Elder User
Joined: May 2018
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Bending rods and blowing head gaskets aren't the common problem regarding excessive boost. Years ago there was a Ford engineer that was involved in the reliability of 7.3 IDIT engines as boost was increased with engines on FoMoCo test stands. Ford found over a period of time when boost was set over 12-15 PSI that the ultimate component that failed was piston wrist pin bores. They slowly became elongated. Makes sense to me, but whatever floats your boat.
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Bending rods and blowing head gaskets aren't the common problem regarding excessive boost. Years ago there was a Ford engineer that was involved in the reliability of 7.3 IDIT engines as boost was increased with engines on FoMoCo test stands. Ford found over a period of time when boost was set over 12-15 PSI that the ultimate component that failed was piston wrist pin bores. They slowly became elongated. Makes sense to me, but whatever floats your boat.
that's why idit connecting rods are bigger then the NA rods
Lead Driver
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I meant to say 20+ in 1.5 sec at 1800 rpm. I like it, i have the smaller 68 turbine, .91 T4. Its way overkill size wise for a 110, but i do plan to go 150 at some point when i can figure out a dual disc, or break down and build this 4R100. Turbo really comes to life at 1700-1800, you can pin it from coast and it will clear the fuel in no time. Good low rpm response, i cant get the pyro over 900 in the DP
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I meant to say 20+ in 1.5 sec at 1800 rpm. I like it, i have the smaller 68 turbine, .91 T4. Its way overkill size wise for a 110, but i do plan to go 150 at some point when i can figure out a dual disc, or break down and build this 4R100. Turbo really comes to life at 1700-1800, you can pin it from coast and it will clear the fuel in no time. Good low rpm response, i cant get the pyro over 900 in the DP
dual disk? Are you running a zf, and if so what clutch are running? I pick up a 400 horse rated south bend kit with evrything pp, clutch, flywheel.
I can't remember but I thought I saw one of the Justin's might have been just running an s366 and making close to 30 psi?
I like the new s360 sxe turbo and want to use the .63 housing, why didn't you run that housing instead of the .9? Is egt limited or not enough fuel to spin it up
oh did I mention this is all going into a bronco