i just upgraded my hy35 to a hx 35/40. my egts went up by about 200 degrees. what could be the problem.

How much boost are you pushing out of the new turbo compared to the HY? Seems to me like boost is a lot lower, or it's taking too long to spool, causing higher EGT's.

The hybrid has a bigger compressor wheel & housing and a bigger exhaust housing. Because of this, it requires more exhaust pressure to spin up enough like your HY35.
This can be accomplished with more fuel/bigger injectors but the exhaust temperatures will still be more than you had stock IMO.
With your stock injectors and module, I believe a stock HX35 would've worked better.

My hybrid worked real good with 100hp injectors but you'd most likely need to upgrade the transmission to run them.

A turned up Cummins can break transmissions/clutches.

im gettin around 30 with the hx and i have got 40 with the hy. just driving up hills the egt goes over 1000.

with a bigger turbo you will have higher cruising egts but your wide open throttle runs will be cooler.

have you noticed that?

how will the egts be for towing

Cruising EGT shouldn't be that much higher.

He might have an exhaust leak. Check the turbo mounting surface and the exhaust manifold gasket area for soot streaking.

I just swapped in a 351cw and it seems like I'm running pretty hot, around 750 cruising and up in the 1100 range on WOT, any thoughts?

Cruisin for me I see 800 to 1ooo but wot it wont pull over 1300.

correct me if i'm wrong, but i've heard bigger ( single ) turbo = higher egts because you have to give more fuel to drive it. if you want more power and lower egts, go with twins?

I would start with a boost leak check and look for soot. How did the turbine disk tip clearance look inside the housing? What size of housing you using? Stock HX35 probably and running the 40 compressor side? Which impeller is used on the compressor side?

blackspeeper, your built tranny and i'm guessing tighter converter that worked well with your hy may be keeping the rpms too low when you are just driving around, not allowing the 35/40 to spool where your hy would. Getting over 1000 going uphill does sound like a boost or exhaust leak, it could be a combination of both.

Sloth, 1100 at WOT isn't hot. You can run these engines at 1250* pre turbo all day.

Chanceray, bigger turbos are slower to spool but move more volume than stock chargers. so you give up quick spool to get more top end power and cooling. More fuel is not a linear relation to higher egt because if you have more air to go with more fuel, it will run cooler than more fuel with the same amount of air. Twins utilize the quick spoolup of a small (usually stock) charger as well as a large turbo for top end cooling so you get the best of both worlds.

I think I know where the boost is leekingfrom