Sorry if this is in the wrong spot but let me know if there is a better place to post.
My tug has CAT 3508b’s I was wondering if anyone knew an appropriate rpm when boost should start to build? Is it an engine standard? Or does gearbox ratio and wheel size effect spool time? Any other info needed I can try my best to get. Thanks in advance.
Paddy
Boost is dependent on load. You can be at full rpm with zero boost.
Sorry for the lack of knowledge. I have limited marine engine exp being a mate, I’m basing assumptions only with car exp where you can build boost just by revving a turboed car. Ill try to get a boost reading underway as soon as I can. It seems to me that the boost should build sooner than it does and if I recall our engineer said its somewhere around 1600 rpm with a max rpm of 1800. This to me seems high, shouldn’t that extra power start to build at say 1400 so you have a longer range of higher power? Thanks for the answer I appreciate any information I can acquire to be more versed in the system. Cheers.
I haven’t worked on a 3500 for a few years, and the 3508 was our port generator and usually ran at fixed loads. It all depends on how the engine package is set up. If the engine is designed to be ran at 1800rpm with a load of 85% than what you’re describing seems fine to me.
Keep in mind turbo cars and turbo marine engines are VASTLY different. Cars are meant to go through the rpm range quickly with very little turbo lag,not sit at a pre determined rpm for long periods of time. Also, keep in mind that different turbos are efficient for different rpm ranges. Smaller the turbo the faster it will spool up and faster it will reach maximum boost, larger the turbo the slower it will spool up, but the greater the boost. They really should be matched to your engine and operating conditions. My buddy had a turbo CRX back in the day with a T04E turbo. Didn’t make any boost till 4500rpm, utterly useless for the street, but it ran 11.2 at the track.
[QUOTE=Kingrobby;179205]I haven’t worked on a 3500 for a few years, and the 3508 was our port generator and usually ran at fixed loads. It all depends on how the engine package is set up. If the engine is designed to be ran at 1800rpm with a load of 85% than what you’re describing seems fine to me.
Keep in mind turbo cars and turbo marine engines are VASTLY different. Cars are meant to go through the rpm range quickly with very little turbo lag,not sit at a pre determined rpm for long periods of time. Also, keep in mind that different turbos are efficient for different rpm ranges. Smaller the turbo the faster it will spool up and faster it will reach maximum boost, larger the turbo the slower it will spool up, but the greater the boost. They really should be matched to your engine and operating conditions. My buddy had a turbo CRX back in the day with a T04E turbo. Didn’t make any boost till 4500rpm, utterly useless for the street, but it ran 11.2 at the track.[/QUOTE]
Thanks, I didn’t expect it to start building boost right away but only having it for the last 200 rpms at most seems off. We mostly run at 1650-1700, the highest the engines (with a load) will touch rpm wise is 1800. I should have mentioned that in the first post, I apologize.
With that being said is 1600 still normal? Dont get me wrong the engines are strong and extremely reliable. But I feel they could grab a bit more power and efficency with a larger turbo range. Does that make sense?
I’ve worked with CAT’s,Cummins,mtu’s and old Detroit’s. Although I do love the Detroit’s cause even though they drink oil, they are almost impossible to kill. But they’re still second to the CAT’s.