Calling all dyno sheets over 3200rpm!

[JasonCzerak]

What does RPM have to do with flow? First off, you have a motor that makes peak power between 2900 and 3100 rpm's. The head on your CR will only flow around 125cfm in stock trim, so I wouldn't worry about a "bottleneck" issue with the turbo you chose. I would worry about a cooling issue. Unless you raise cam duration...you aren't going to raise the peak power curve.

I'm not talking flow in the head. flow though the turbo "first" then we'll work on flow though the head (unless someone's got the head question.).

A turbo designed to run between 1600 and 3200 isn't going to work well at 4200 correct (see stock turbo...)? unless it's already "too big" for the 1600-3200 range. like RoberP's (3600) and McRat's hold consistent power to 4200rpm. I'm sure my stock HX35 will spin so fast it time travels back in the past or something. And well, heat is a small issue, heheheh.

What I'm looking for is a turbo that will stay cool at the higher RPM band. Spooling at 1600 and towing 15,000 isn't a big deal to me. I don't mind shifting at high RPM's if the turbo is better up there.

Am I clear a mud? I wish I could be more technical with my questions.

 

[JasonCzerak]

What is the point here?:bang
Big sticks and a single CP3 on an LB7 will not get you much if any from what I have seen. Granted I can not say the injectors I mess with where the same as you put in. Stock LB7 injectors are a very capable peice power wise.



I will post a graph when I get back home. I made just over 500rwhp at 2800rpm and was still making over 400 at 4000rpm.

I have a similar graph for my CTD, but to 3450. Drops off at 3500 and stops at 3700 I have yet to get it scanned (new job, large campus, not very "paper friendly" here as they are a bunch of tree huggers. Not a scanner to be found in the building I'm in).

 

[SpicyJam]

Jason you are beating yourself up man, you should talk to Aron or I some time. later, Jim.

 

[JasonCzerak]

Jason you are beating yourself up man, you should talk to Aron or I some time. later, Jim.

Yeah. maybe a more in person conversation will help out.

I"m just trying to understand in laymen terms, even more so for ppl who are like me (and there are many) as to why this turbo over another. I have a good understanding for a normal rpm range. If I didn't feel the want to do more then 3000rpm, 64/12 would be perfect.

But things HAVE to change when tuning for 4200 vs 3200 and no one seems to have a clear answer other then "mine works, look at my graph".

 

[sootman]

Yeah. maybe a more in person conversation will help out.

I"m just trying to understand in laymen terms, even more so for ppl who are like me (and there are many) as to why this turbo over another. I have a good understanding for a normal rpm range. If I didn't feel the want to do more then 3000rpm, 64/12 would be perfect.

But things HAVE to change when tuning for 4200 vs 3200 and no one seems to have a clear answer other then "mine works, look at my graph".

When you get the ISBE to make power to 4200rpms...there should be an engineering job here at Cummins for you.

 

[McRat]

In my experience, the size of the compressor on a turbocharger is the limiting factor for the Peak HP rpm. As I move the charger size up, my peak HP rpm has always moved with it.

 

[JasonCzerak]

When you get the ISBE to make power to 4200rpms...there should be an engineering job here at Cummins for you.

I'm playing the "wait for the smarty to do 4200RPM" game. and after that I plan on that turbo. Or Spring of next year, which ever comes first.

 

[sootman]

In my experience, the size of the compressor on a turbocharger is the limiting factor for the Peak HP rpm. As I move the charger size up, my peak HP rpm has always moved with it.

You've got ported heads...right? You've got to be able to move air to use air.
You can't compare a V8 to an I6 when it comes to peak rpm power levels. I6's have inheritently lower peak RPM's.

I bet you would trade some of those rpm's for some of the I6's torque.