andyr354

Just reading posts and looking at people talking about boost #s in the mid to high 20 and low 30s and wondering what I am missing to not be there.

Right now I can get around 22-23lbs at WOT but most of the time pulling the highest is 19 or so. I have the AFC not quite at its deepest setting, stock 18.5 turbo, stock exhaust straight piped, and thats about it.

I think the fuel screw has been turned in some but I don't know how far since it was already done when I bought it. The collar is still on it though I think if I am seing what I think I am.

Maybe I should not worry about it since it does what I need it to do. Pulls the jeep nice now after adjusting the AFC friday night. Didn't mess with the star wheel.

If I leave it the way it is my clutch and tranny will probably be happier anyway.

92DIESEL

I dont know but the max I get is 13-14 at WOT uphill with load! .

I must be doing something wrong, or its just the 21cm housing and stock everything else

jiMMyCTD

See my Sig..... FUEL mods are your friend.

jiMMy

Tuckerdee

I think you'll also see a bit higher boost with a smaller turbine housing. With a 16cm housing and NO fuel mods, I got about 18psi max boost. With 2 turns in on the fuel screw, that jumped to a max of about 24psi.

Buckshotmckee

More fuel, More Boost.

Den

I have the 21 housing, stock injectors, stock exhaust. Only things I have done are the high idle, full power (2 turns) and my AFC diaphram was already about 60% turned between lowest and highest. Before I fooled with the pump I only got around 14 max. Now I get 24

I think one of the easiest and important things is the high idle setting. I would say especially on the autos it's noticable because you can just keep your foot planted on the floorboard through the gears. People are prolly sick of me saying it, but I can't say it enough

Make sure you have full travel in the pedal.

The threaded stud going along the drivers side of the pump that looks like a throttle stop is the high idle screw. The best way to set this is to do the following:

The rod with the 2 black plastic pieces on it, disconnect the back half.
Loosen the retaining nut on the high idle screw.
Hold the pumps throttle lever at max throttle (with the truck OFF of course )
Now turn out the high idle screw towards the back of the truck. Turn it way out until the throttle lever is no longer touching the screw.
Now turn the screw back in until your moving the pump throttle lever forward so it's hitting the screw and the lever is not stopping before hitting the screw. Turn it in enough so it's slightly moving the lever forward. Tighten the retaining nut.
Reconnect the throttle rod.

Now check to see that the throttle lever on the pump able to fully return to the low idle screw. Let it back slowly instead of slamming back to make sure it can rest on the screw. I have my idle set at 800 and I have the rod set so I can get all of the travel out of the throttle arm. But I have to be at 800 idle to do it. You may need to adjust the rod to make to get the full amount of travel. Also make sure your pedal is moving the throttle shaft to the high idle screw.

Take a drive and smile
That right there makes a noticable difference.

I this needs a write up with pics, let me know and i'll make one for my site.

Den

fearthedeere

Prestacks i peged my 30 psi gague now im makin bout 26. back pressure is bad

flyingd

If you turn up the fuel screw, besides the extra boost will you have higher egts

jiMMyCTD

i would say yes you would have higher egt's then you need to open teh exhaust and intake to compensate.
jiMMy

Charliebrown38

Den, Nice site! I would like to see your writeup above with some pics posted on your home page.

Charlie

nascar mark

As mentioned, more fuel = more boost and higher egt's in most cases. Boost is a combination of fuel backed with air. A stock H1C turbo is very inefficient above 28psi and will produce hot boost, not cooler efficient boost that is needed for power.
With a good turbo, true 4" turbo back exhaust and lots of fuel I made a steady 50psi with my old engine. I don't recommend pushing it that hard without head studs or O-ringed head but I got lucky for close to a year at those #'s. Also 4" exhaust isn't nesassary until 300hp but I do recommend changing out the stock system because of the poor restrictive bends from the factory.

andyr354

Well, this is the way mine is set:

Fuel screw in as far as it can go with collar still on it and no threads showing by head of screw.
AFC to near deapest setting
High idle turned out 2.5 turns
Stock exhaust straighpiped, I don't see that bad of a bend over the axle?
Factory air intake
Factory turbo at 18.5cm

Like I said I get around 22-23 max and 18-19 while towing. Still just doesn't tow like my dads 02 does and its bone stock. Maybe I should check the fuel pressure coming from the lift pump.

I have been getting stuff ready for the BHAF. Is it going to affect power any or just help with EGTs?

jiMMyCTD

usually helps with egt's mostly. id say you are right on for boost number with those mods. to start waking her up you really need injectors custom intakes and exhaust and other fuel mods..

apwatson50

92 Diesel, Have you checked your intercooler boots? When I first got my truck it would only pull 13 to 14 lbs even after the 16 cm housing! I got to checking and the inner fender rubber rubbed a hole in the first boot coming off the turbo. There was about a 1/2" hole so that wasn't helping.

Dieseldude4x4

Mine runs 44 to 45 psi under load.