whatsup1287

Here is the current engine set up. II 62/65/14 (waste gated to 25psi) over an s400. All piping for twins was bought from source auto, JL machine 435 injectors with correct spray pattern, 181 delivery valves, 4000gsk, 60lb valve springs, air dog II lift pump, tork tek over flow valve, BD diesel afc spring, no fuel heater, 100 plate push forward, o ringed head, head studs, 18* timing ATS 3pc exhaust manifold. The truck will build 60+psi of boost.
Has a built HTS trans and I’m running 3.55 gears and 35s.
The truck will hit 1200* just hitting the on ramp getting on the hwy empty. If I get on it hard on the hwy I can hit 1400* quick.
Pulling a 16' equipment trailer going 70mph I'm running 1750rpm 10psi boost and 1000* pre turbos on flat ground. Any incline will take it to 1100+ and some hills I can’t even maintain speed because the egts will go over 1200*. The trailer is prob about 3000lb and this was with nothing on it.
I had a Super B special single, but couldn’t keep the EGTs low enough so I sold that for the II 62 over a s400 setup hoping to fix the issue.
The truck get parked for winter, but I would like to get this figured out before it becomes a spring time issue.

TurboDeezul

Heck, I'll go first. I'm just guessing, and probably full of it, but it seems your fueling capability is laughing at your ability to move air.

Maybe. Is that secondary a bit small, specifically the compressor housing? Is the difference in the size of the chargers TOO different? I'm just curious, actually, I don't really know. Turbocharger voodoo fascinates me.

Is it smokey? Any boost leaking anywhere? Boots, gaskets, etc...

That's a lot of fuel though, right? That secondary a restriction in your overall flow path?

Okay, I'm all out of ideas. I hope some others chime in here with the right answer.

Tate

Have you verified your temps with another pyro? My fueling is comparable to yours, and I'm running a super b special, and temps are very controllable. Next would be looking for boost leaks. Might want to verify timing as well if you can.

HOHN

There's nothing wrong with the function of the parts you have-- they are all working properly. Rather, the combination of parts you are running doesn't work well together-- which is probably obvious to you now.

If you're going to run 35s with 3.55 gears, you can't have a big-horse power air handling setup designed to rev and make big peak HP (unless you plan to tow at 90mph). Instead, you need smaller turbos with small housings that will respond quickly and choke on the higher range where big HP numbers are made. So, you have a truck setup one way, and an air handling setup made for a truck running 4.10s on stock rubber (i.e., higher revs).


I think you'll need to do a little more tuning to make your current setup work. If you want to stick with your excessively tall (for towing) gearing, then you'll need excessively small turbos for the fueling you have. Then you end up having all that fuel for naught, since you'll never pump enough air to burn it.

Bottom line: to make your truck work properly, either tire size or gearing has to give. Stock rubber with 3.55s would probably work, as would 4.30s with the big tires.

I'd recommend either giving up the big tires, or re-gear to run them properly. I'd recommend a minimum 4.10 for your setup, with 4.30s being ideal if you can find a R&P in that ratio for your axles.

4.56s are also within the range, but are really more towards the "tow heavy on 35" tires" range."

If you're willing to eat a little in mpg, the 4.56s will annihilate your EGT problems and make your truck a towing monster that won't even notice altitude or high load.

JH

whatsup1287

This seems to be a very common twin set up.
Most places sell this set up as a towing set up.
The truck really isn't smokey at all, so I cant see it being over fueled.

whatsup1287

I haven't checked with another pyro, Im thinking thats next on the list along with the timing. The truck was running just like this before I bumped the timing up, it just has a little more top end now.

whatsup1287

I was running 4.10s until I swaped in a Dana 80. When I went to the 3.55s my egts didn't go up more than 100* while towing.
Seems like if I did a gear change that my final drive ratio in OD would be around the same as it would be now in drive... I have tried to tow in drive, and on the flat ground it might help 50*. On the hills it helps, but it still gets hot.
My old truck (97 2500 4x4) was running 3.55s with 35s and an hx-35 over an HT3B, smokey 370s, 4000gsk, fass system, and the same plate and towing heavy it wouldnt get over 1000* unless I was being stupid.

Mike Holmen

I would start with the checks like Tate suggested. Boost leaks, and timing is a good check. Could tweak the AFC some to limit fuel as low boost conditions.

The pyro could be wonky, see that before on my truck. Where is the probe located at? How far in the exhaust manifold did you go? Are you running smokey when just driving on the hiway? Could check the valve lash as well?

Whats your boost numbers and egt's at wot? Sounds like you have a nice set-up, the S362 has a very small internal gate, and will limit top end power some. We typically run external gates on our twin configurations, helps the drivablity and top end power.