Cat c15 Turbo upgrade

I don't believe that's true. I ran a bigger turbo with just a different tune. Went from 30 psi to just shy of 45. Wasn't really any more turbo lag than stock and when the turbo did start to spool it did it fast and hard

 

Whats making you think the turbo you have now isn’t big enough?

 

So you just think its to small?? What are the numbers from the gauges telling you? I know you said your boost seems low but what about your EGT’s what are they doing? Is the water temp and oil temps staying in check on long hard pulls? This is the info you need to determine if something is actually running with in its designed parameters. Also since the was a compound turbo’d engine from the factory with IVA’s what all has been changed over to make things run right with a single turbo?

 

80/1.45 is what I would do

 

Seeing that your pyro is that hot with only 26psi of boost something is definitely jacked up with air flow thats for sure, and sounds like the turbo is to small.

Does the turbo have just a general whistle or does it sound like its spinning super fast with a higher pitched whine? Mine whistle’s pretty loud up tell about 25psi then starts to get quieter and has more of a whine as its rpm’s go up as it builds up to around 30psi, so I know its getting to the point where its choking the engine off in the higher power/rpm band.

You also mentioned surging? Like as the turbo spools up or when you shift?

Normally turbo’s dont surge or flutter unless they are to big, so as they spool up the boost pressure is climbing faster then the drive pressure so then the turbo stalls out somewhat.
Now if on the shifts its surging or barking its because of the sudden drop in drive pressure when the fuel is removed and what you’re hearing is the boost pressure stopping the turbo and the air coming back out the air cleaners. This can and will lead to turbo failure sooner or later and they’re not designed for sudden air flow changes like that. Remember the turbo spins at somewhere between 10,000-100,000 rpm.


My factory reman 2ws has a supposedly 550 file in it but Im not sure which one Kustom Truck put in it. It runs 28-30psi and during the summer it’ll see 975-1000 at the most post turbo temps, fan locked on she stays at 195-200 water temp and 215-220 oil temp. At 106,000 gross I pull 6% grades at 30mph. I will eventually get mine turned up in the 700hp range and will most likely throw a set of msx 625 compounds on it. I think @lester has a setup like that.

 

It's hard to diagnose your true issue without knowing what has been done to that engine. IVAS or compression changes?!

But yeah I think you will see a huge difference with a proper sized turbo. When I was running a larger single I forgot where my pyrometer was at because it was never anywhere close to an issue and when that turbo started spooling up you felt it in your seat.

 

I think all the xs series turbos are all the same no matter the HP rating. The SDP setup is apparently the one to go for. But I'm far from knowledgeable about turbo specs. I do like the bxs compound setup I have on my 6nz. For the constant starting and stopping I do. And the Jake's work way better. If I was OTR I might switch back to the big single. I don't know