For MCS, at what rpm does the turbo start to scoop up? Whats the mph at that rpm?

(so below that rpm for cooler engine temp, mpg for cruising)

 

you mean spool up?

 

hahahaha

Thats the first thing I thought of when I read the title of this thread.

 

1500 rpm, in my experience.

 

The twin spool turbo has a really low spool up speed. Like MPowerF1 says, it's nearly immediate. Having said that, the turbo doesn't seem to ding the milage much, just keeping the speed constant seems to be the best way to get good milage. I once got 42 calculated MPG by cruising all day at 60 mph using cruise control.

 

Check this info out.

Attachment 41226

 

Great piece of info..!
This suggests that the MCS is a direct injection engine, while the MC isn't.. something I wasn't aware of!
Thanks Oxy

 

It's does spool up rather fast, but you really FEEL it around 1500-2000rpm on the butt dyno.

 

You start to get full boost about 2500rpm, it starts to spool up below 1500. To get speed, stay above 2500-3000, to get fuel economy, shift before you get there.
Also, if you're cruising at any speed (70-75mph) you'll be into some boost whether you want to be or not.

 

I wonder if the current MCS engine has diff specs-- that attachcment is dated 2004, and only details the 118 and 148 HP versions

 

Is there a source for the claim that cruising at highway speeds will necessarily put you into boost?

 

Not sure about source, but I'm guessing the basic idea is that if you're engine rpm & exhaust flow is high enough (which it is during highway cruising), you would definitely spool the turbo.
Anybody with boost gauges willing to testify?

 

In my factory JCW I run at about 10-12inches of vacuum while cruising.

 

Huh.. I would have thought otherwise..
I need to get me some boost gauges..!

 

In my MCS the boost starts to build at fairly low RPMs when accelerating, but really kicks in around 2500. When cruising at 60 mph or higher my boost gauge reads just over one PSI, lower speeds (ie: lower RPM) it settles to zero. I have never seen the gauge reading in vacuum under any driving situation.

 

and then when i give it any gas it will jump to 10psi and climb as high as 20

 

Shortly after I got my '08 MCS, my service manager kindly copied the factory spec sheet for me. It states full torque (177lb.-ft) from 1600-5000rpm and overboost (191lb.-ft) starting at 1600rpm. The twin spool turbo explains this quick spool-up, but you have to be some kind of engineer to understand how it works. The big torque and quick spool-up explains why the
Getrag 6spd is OD in 5th & 6th gears!
Turbo On - Dwight