5x12's and an HE351cw

[Raymo]

I can barely stand my turd of a truck any longer, and after two years it's time to spend some money in the name of performance Besides, I'm tired of being shut down by the BBC's I gave up for my trusty Cummins

So my question is, are 5x12's and an HE351cw going to run too hot while towing up to 14k? I already own the turbo.

So far I have bad stock injectors, LPPP, 4" exhaust, 366 spring, M&H M2 fuel pin, smoke screw down two turns (flush with the nut), star wheel down half a turn, and the fuel screw in the stock location. Stock timing as well. Right now I run 1300* max with a poor amount of boost.

I accidentally dropped the collar from the fuel screw when I had the top off for the 366, and when I replaced the screw the factory number of turns I had only gained an additinal half turn before it stopped

Oh, and this is a '93 engine, 5 speed 4x4.

[PToombs]

It's going to be marginal. I have 370's and a hybrid HX40 with a ground pin and it's hot just driving it hard. I have the timing bumped also. Pulling the trailer is tough, even with the valet switch off the EGT's get up to 12-1300.

[CumminsPower59]

I got 6x11's (slightly bigger than 5x12) in mine and they get plenty hot when towing, I really have to watch it as to not peg the pyro. In short, you will need some more air than that 351cw can put out to cool 5x12's well.

[StL1stGen]

I say it depends on terrain and your right foot. I tow 7k lbs of mud truck and trailer with more pump mods AND bigger injectors. I can right foot regulate mine to 1000-1200 degrees all day towing through misery. That's not to say that 7k more lbs won't add heat I just think it can be done sensibly.

[Raymo]

Well, I decided to go with some DDP II's. Just got done installing them, so after I warm up a bit I'll check for leaks again before I go out and see what she'll do now. My stock injectors have mounds of carbon around each hole. They look like ant hills

[FourSpeedSteve]

I just installed new injectors Saturday in my 91.5 IC truck. I got Scheid Lightning 106's with 5x.013 tips, 3700psi. They are awesome! I run an HX35 16cmW/G, and had to turn my pump down a touch for the heat.

Before I installed the injectors, I had turned my fuel screw in 2 full turns, star wheel bottomed (1 3/4 turns), fuel pin stop screw down 1/2 turn, and rotated the pin 90 degrees to deep side. With this set-up and my HX35, I could make 28-30psi boost, and EGT's couldn't top 1000degrees (probe in rear half of manifold, pre-turbo). With the new injectors, and not touching the pump, I could bury 1600 degrees in a long WOT pull in 5th gear. The 35psi boost gauge was slamming so hard into the stop peg, that I thought the needle was going to break off! I ended up rotating the fuel pin back to stock location, and backing the starwheel off to 1 turn down from stock. This made a drastic difference in temps, as it will get to 1300 now, and 1400 if I go WOT in 5th gear. Boost checks in at 33-35 psi now. BTW, I kept the fuel screw in at 2 turns. It still makes lots of smoke when I get on it, but mostly cleans up with the boost.

[jkidd]

he351 will outflow an hx35/40 hybrid. it will support the same amount of HP as a super B but spool a little faster. If the wastegate opening can be enlarged so drive pressure can be kept in check it will support a little more than the super B.

Many of the DDP injectors are not the correct spray pattern. and 5x.012 are going to flow about the same as a 9mm non intercooled, so the ddp 50HP 155* for a non intercooled are actually a step backwards. you can play around with the shims to sort of correct the spray pattern difference to work more optimally in the intercooled engine.

[1990]

I just installed new injectors Saturday in my 91.5 IC truck. I got Scheid Lightning 106's with 5x.013 tips, 3700psi. They are awesome! I run an HX35 16cmW/G, and had to turn my pump down a touch for the heat.

Before I installed the injectors, I had turned my fuel screw in 2 full turns, star wheel bottomed (1 3/4 turns), fuel pin stop screw down 1/2 turn, and rotated the pin 90 degrees to deep side. With this set-up and my HX35, I could make 28-30psi boost, and EGT's couldn't top 1000degrees (probe in rear half of manifold, pre-turbo). With the new injectors, and not touching the pump, I could bury 1600 degrees in a long WOT pull in 5th gear. The 35psi boost gauge was slamming so hard into the stop peg, that I thought the needle was going to break off! I ended up rotating the fuel pin back to stock location, and backing the starwheel off to 1 turn down from stock. This made a drastic difference in temps, as it will get to 1300 now, and 1400 if I go WOT in 5th gear. Boost checks in at 33-35 psi now. BTW, I kept the fuel screw in at 2 turns. It still makes lots of smoke when I get on it, but mostly cleans up with the boost.

You should try to turn up the star wheel. It will help clear up the low end smoke and give you better acceleration.

[Raymo]

he351 will outflow an hx35/40 hybrid. it will support the same amount of HP as a super B but spool a little faster. If the wastegate opening can be enlarged so drive pressure can be kept in check it will support a little more than the super B.

Many of the DDP injectors are not the correct spray pattern. and 5x.012 are going to flow about the same as a 9mm non intercooled, so the ddp 50HP 155* for a non intercooled are actually a step backwards. you can play around with the shims to sort of correct the spray pattern difference to work more optimally in the intercooled engine.

Hmmm, I've been driving on the stage II's, "75-100hp" since last Saturday. They don't haze a bit (like my worn stockers did) and the engine runs sooo much smoother. If I lean into it a little bit though, it'll let out a decent dark grey/ black cloud. I've still got fueling issues though, with the new sticks I've maxed out at 15psi of boost (I know ) so that leaves my injection pump. Everything else is brand new, lines, tank and lift pump. Still fires half a crank and does about 16mpg with 4.10's, 19.5's and 34" tall tires. It's just lazy and runs 15psi gettin' it, at 1350* with the new sticks, up from 5-10psi and 1300*.

Edit: I have checked for boost leaks, I have a mint 1st Gen intercooler, and dip tank tested pipes with all new silicone boots and new clamps.

[Tacoclaw]

Have you checked for boost leaks? That's mighty hot for it to be making that little of boost.



Doh, nice edit.

You could also have a leak at your compressor housing, or your intake manifold gasket...

[Raymo]

I'll double check the compressor housing, but the manifold gasket sounds like a good possibility. I'll throw one on it, just to see.

The donor truck for my drivetrain sat for 4 years not running. Many people messed with it trying to start it but NOT ONE person put a new fuel filter on it... Fired up like it just shut off with some fuel fed from a 5 gallon can and a fresh filter.

The throttle shaft o-ring is just now starting to seep, and I had to free up the AFC pin that rides on the fuel pin. So I've just been hoping the next link in the fuel system has been my weak point.

[Tacoclaw]

Yeah, just throwing out some extra ideas before you have to dig into the pump. Especially right before the best season to drive it around.