16cm2 turbo housing

[92 cummins]

the 92's had a 21cm turbo housing which was horrible at spooling up, the 16cm turbo housing has way better spool up.

[Ace]

... 14s you need to start worrying about choke down unless you install a waste gate.

WTF is choke down?

[cougar]

... 14s you need to start worrying about choke down unless you install a waste gate.

WTF is choke down?

Like sticking a potato in your tail pipe. It restricts your exhaust flow. 16's are good, smaller than that gets iffy real fast without a waste gate.

[Ace]

... 14s you need to start worrying about choke down unless you install a waste gate.

WTF is choke down?

Like sticking a potato in your tail pipe. It restricts your exhaust flow. 16's are good, smaller than that gets iffy real fast without a waste gate.

That's pretty much BS. There's no exhaust flow restriction, except in your imagination. High EGT if you have enough fuel, that's about it. Wastegate won't even come into play without bigger injectors. Even a non-ic truck with a good pump turned all the way up is going to max out around 40psi non-wastegated.

Why do you think they make/sell non-wastegated housings? Because wastegates are completely unnecessary in most applications short of highly fueled 400hp+ engines. It all depends on the specific combo you are putting together - not some tailpipe potato fantasy.

[DoWhat?]

I don't know about potatos... but I do know that it will throw your drive pressure/boost ratio off and make the compressor surge. My truck with stock non-1/c injectors and a 12cm with the wastegate disabled surges like a big down with the trailer behind it.

[Ace]

That's what the MWE slots in the compressor upgrade is for.

It's been awhile since I towed, but my 12cm with the wastegate disabled pulls hard to defuel above 3krpms through the gears making close to 30psi boost running like a raped ape all the way.

[dpuckett]

I have to agree with cougar- the 14cm is getting into choking range. I have towed with a 12, 14, and 18.5. All on the same truck (nonIC 91, tuned pump, stock injectors), no other changes.

With the 12 and 14, I noticed no difference in spoolup- pretty fast. BUT, they were also hotter when towing with a PDR HX35 (MWE slot) than was the 18.5. I noticed a definite change in rate of EGT increase after about 30psi when pullig 10K up a grade. No drive pressure gauge, so I cant comment on that ratio. SO, if you keep the boost within the limits of the turbo map, you MAY get away with faster spoolup and better EGT, but I'll take a little lag to improve my MPGs and keep towing EGTs in check.

Cruise EGT was actually lower with the 18.5 than the 12 or 14. It is also lower with the 16 in my current truck vs the 12 the turbo came with when I bought it. Boost is also lower, telling me the engine is working less to move te same load down the road.

For my money, the 14cm is no better than a 12 in a 1stGen, and I wont run either one. I like the 16 as an all around compromise- good spool, yet lower EGT when towing. Your mileage may vary.

DP

[Ace]

Daniel, I suspect the EGT issues you saw are strictly due to a non-IC setup running the turbo towards the end of or even outside the MAP. You are not getting away with anything after 30psi and an HX35, regardless. I'll bet your EGT issue would have been mitigated to point of making the difference seem much less significant with an intercooler.

Hot air in = even hotter exhaust out.

[DoWhat?]

That's what the MWE slots in the compressor upgrade is for.

It's been awhile since I towed, but my 12cm with the wastegate disabled pulls hard to defuel above 3krpms through the gears making close to 30psi boost running like a raped ape all the way.

I'm running the GDS 60mm upgrade... its a hoot empty, but that little exhaust housing hates the trailer.

[Ace]

No doubt, you guys are talking about small turbos with big injectors and no intercoolers. Even the stock non-IC injectors are big for those turbos. What do you expect? All I'm saying is the exhaust turbine is not the primary factor affecting that situation, like everyone seems to believe.