Mid 20s boost IDI !

Looking for more power ?
http://www.ford-trucks.com/forums/708676-forged-dishtop-or-hyp-flat-tops.html
Read down to the posts by Dave S.
For those of you that don't know, Dave uses his truck for work/dd.

thats awsome mid 20's out of an idi

he lowered the compression ratio.

to what? guess i didnt read it all just got excited over boost and stuff

Yep. Everyone agrees that a lower CR is needed for much above high teens boost and longevity. The only question is how to do it without weakening the pistons or rods or whatever you modify. I wonder how many miles Dave has on his IDI. An intercooler plus lower CR pistons and turbo IDI rods will be in my future if I keep mine beyond the lifespan of the current engine.

Ahhh, he shaved .040" of the top of the piston to bring the CR down to 20.25:1. Someone get him to come over here and explain things a bit better.

i asked and he never got back to me. he also has some gasket work to keep it together. real nice guy and uses his truck hard.

He just used cut down hypertetectic(sp) pistons and studs. Lowered his compression to 20-1. He wanted to go lower. But figured he'd have cold start probs.

I've tried to get him over here. Tried to lure him with a Moose Pump Thread. Guess He's happy over there?

20's WOW! what kind of gaskets? copper??

I almost think that felpro or Victor-Reinz gaskets would hold that kind of boost it would be the top end and the dynamic pressure on the motor that would be a concern. The head studs should reduce the likelihood of losing a gasket and the reduced compression will lower the dynamic strain on the motor. I wonder how the valvetrain handles that kind of strain seeing it wasn't even designed with a turbo in mind.

I would like to see dyno numbers as well. If you are going through all that trouble and expense, wouldn't it make sense to see if it made a difference? If you have to spend $2000+ to get 10 HP, then why bother? I also noticed he wasn't afraid of it seeing some high EGT's, like 1200, would like to know longevity as well, but it's cool that someone is playing with things successfully, but to me, the proof is in the numbers.

Dave doesn't run an I/C due to his plow bracket.
If I remember right, he's running fel-pro head gaskets. He didn't have to do gasket work to hold it together, but stud the intake. He actually blew the intake to head gaskets out of it.
Here's his build thread/updates.
http://www.ford-trucks.com/forums/509299-engine-overhaul.html
http://www.ford-trucks.com/forums/512397-well-it-is-not-gray-what-do-you-think.html
http://www.ford-trucks.com/forums/509339-hello-new-engine-is-going-back-together.html

I don't need to see numbers to know that his truck will flat out haul, mine will run with a stock 6.0, and I am only pushing 15 psi and never see more than 950 egt unloaded. I fully intend to break 20 psi on my engine without dropping the compression.

82F100SWB said:

I don't need to see numbers to know that his truck will flat out haul, mine will run with a stock 6.0, and I am only pushing 15 psi and never see more than 950 egt unloaded. I fully intend to break 20 psi on my engine without dropping the compression.

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But do you know for how long? Seeing the numbers are the only real measure of it, you might be running against a sick 6.0, but even then, the ones I have driven they were all pretty sick. Not to mention, by the time you get so much money into something, and it only runs as good as something you could have had for the same money (like an OBS 7.3) then why bother? Working something to the limitations where longevity will not be there, versus something that in stock trim is just as capable, makes not sense to me. Just my .02 worth.

My truck has been running as it is for the last 2 years and 35K miles(it is my DD, the F150 I bought for that purpose turned out to be too expensive to run if it isn't working) with no issues, with lots of towing in the 18,000-23,000 GCWR range. Very few of those 33K miles were easy highway miles, I have a lead foot, and almost all the highway miles I put on are towing. If anyone's truck is going to die from making big power, it will be mine, I'm not scared of big boost or high egts, I want to find the limits for reliability and longevity; so far, I have yet to come near finding them and I have 3 spare IDI's for when I do find them. And, I will share my findings, not just quietly replace what broke and not say anything.
Don't think I have any big money in my truck either, I paid 4x as much for the turbo than I did for the truck itself, and I got the turbo kit for $1200 with a new turbo...
My 6.9 will easily walk all over an OBS 7.3 in stock form, and no question would have ate my 00 Super Duty for lunch. Heck, I ran with an 05 Dodge Dually one day, and he only got me by top ending me, we were very nearly even until I ran out of rpm.

82F100SWB said:

I don't need to see numbers to know that his truck will flat out haul, mine will run with a stock 6.0.

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