Just like the title says. What is the max boost I would be able to run safely if I studded the heads? I don't want to touch the bottom end if I don't have to. My end goal is to get 200+ hp to the wheels. I'm still in the planning stages of building my truck so I want to gather all the information I can. Thanks in advanced
-Kolby

 

In not sure about studs, but by numbers, my truck is supposed to be about 200 at he rear wheels. I'm running an 80cc IP with a factory turbo and upgraded exhaust. I don't have dyno numbers, but it will out pull a stock first gen powerstroke and hang pretty good with my uncle's 99 stroke. I'm running 12 psi boost max.

 

Kolby.,..in addition to head studs use the R&D camshaft, it bleeds off some of the compression for higher boost, i myself am going this direction, as well as re ring kit in bottom end, re ring kit is the cheap part of the horsepower equation but should never be overlooked, the cam is not priced very bad either, the most expense you willhave is in the pump and turbo

 

my brother is running 28psi boost with his head studs at 150ft/lbs of torque and he is running the r&d camshaft and he is at 350hp at the rear wheels and it holding strong.

 

What pump and turbo is he running

 

R&D stage 3 injection pump 190cc with a s366 turbo

 

https://www.ford-trucks.com/forums/1342155-some-dyno-numbers-and-turbo-info.html

This is the thread that justin from R&D started on my brothers truck

 

my 88 with 949,000+ miles on it has been running 12 to 16 lbs boost for the past 490,000 miles and has never been opened up. it will run over 16 lbs, if i really load it up, but i try to keep it under 16.
i know some others that ran 20+ lbs boost with no problems. but it is recommended to run studs if you are going to run over 15 lbs boost.

 

Those numbers are very impressive. If I remember correctly the block has been reinforced to help hold the power (mainly crazy torque numbers). Not sure if the OP wants to invest that much.

I would say that with head studs torqued correctly your limiting factor would be your EGT's. An intercooler and large exhaust could help greatly with this. With this you should be able to max out the stock pump.

Remember, it is quite possible to make more power on lower boost numbers.

 

Stock IDIT bottom end, stock compression, everything. Might have a girdle and main studs.

200whp is easy, fresh IP / injectors (doesnt have 280k on em) with decent intake /exhaust, and really any one of the "stock" turbos. Shouldnt need studs, but id wager the cam would help some, as would an IC

 

Yes, it was pretty much a stock block/rotating assembly set up. Here is what is listed in the thread:
94 IDIT rebuilt 20K
Stock compression
R&D Girdle Kit
R&D Stage 1 cam
Head Studs@150ft/lbs
RD2-90
R&D Prototype Stage 1 injectors
R&D Stage 3 Turbo Kit
HX35 12cm housing

The only real structural mod is the Girdle Kit and then the head studs. I am sure the Stage 1 cam helps some since it would reduce the dynamic compression ratio some, though I do not know by how much.

The stock 7.3 IDI Turbo engine was rated at 190hp and 388ft/lbs at the crank. Drive-line losses vary, but with a 20% loss it would give you 152hp at the wheels stock. To get 200 at the wheels you would need 250hp at the crank, a 60hp increase.

To be honest, I don't know what the factory boost numbers are, but wouldn't think it would take much more to get you to the 250chp number. Like hairyboxnoogle said, I would think that with the proper intake/exhaust to allow more air in/out as well as better turbo function you should be able to get close and also allow you to turn up your pump some. If you added an IC you would be able to turn the pump up even more. While the IC would cause your boost numbers to drop, it should make more power at the lower boost levels and keep your EGTs in check....thus allowing you to add more fuel.

 

The big numbers were with the 190 pump and s366, not the 90 and hx35. Also, the stage 1 doesnt drop all that much compression, like half to one point justin was thinkin.

Stock turbos were wastegated at 7.5-9psi and have a smashed downpipe / restrictive muffler. They were also calibrated at like 62cc, a stock 7.3 pump in good shape should flow 80-85cc turned all the way up. 80cc x 2.7= 216whp. For a non intercooled / stock turbo setup i would use a more conservative 2.5whp/cc which still puts you at straight up 200whp.

A really efficient setup should run around 2.7whp /cc injected. An inefficient setup would be around 2.4

All that said, lots of guys have ran maxxed stocker and 90cc pumps for ages with no headgasket problems. I was seeing 22+ with the restrictive hx35.

 

I see 12psi loaded and rarely hit 1100egts. But I have found that timing is everything. Mess with the fuel,retime. My IP gave me some problems awhile back. Truck turned into a smokey slob. Egts went up pretty bad. Timing was off. 1\2 a degree makes all the difference sometimes.

 

iirc oem boost of the factory unit is set around 7 psi.
chip truck hits 14 psi @ a cool max of 900-1000 egt.
( @ 8k lb curb weight,she can hit 80 mph with ease well within a 1/4 mile...theoretically )
log truck's wg hasn't been messed with and peaks out around 10 psi.runs cool as well of course as both trucks are intercooled.
it's not hard to surpass the first gen PSD's power.

keep in mind,the "stage 1 cam" will cost you power over oem and for sure the torque cam in the powerband where you'll be spending 95% of your time on the street.....unless you've got an f-super duty.then it's probably a match made in heaven at 50+ mph with a od trans.
imho you don't want a "stage 1 cam" but it's great to have available for those who might need one.i think the grind Russ sells should be the one titled stage 1 with Justin's labeled stage 3.calling an upper rpm power band grind a stage 1 is misleading.

 

HD250....I understand what you are saying about different can profiles. I have a hot cam profile in my track car that causes me to lose torque down low as a trade off for higher rpm power.

You mentioned the torque cam. Were you referancing the type4 torque cam. My understanding of its profile is that it increases low end torque in NA engines to help towing characteristics. Am I mistaken? Looking at dyno graphs of the torque cam it looks like it peaks earlier than the R&D cams.

Can you expand on this?