I have a stock 2008 EVO X GSR. I was headed back from a quick trip to Arizona. I normally have no interest in the interstate highways, but there I was in West Texas where the speed limit is 80MPH. In high gear, that puts the RPM at around 4K just cruising along. I was wondering if the turbo was on full time at that point. Second question, if it was on, any problem running it that way for a couple hours until the limit drops back to 70MPH?

I did a little testing doing a few 80-100MPH sprints. No turbo lag whatsoever that I was able to detect.

Thanks in advance!

 

At that RPM the turbo is well spooled and responds well to throttle inputs. However, you are not putting any psi through your motor until you bring the motor into some load either by increasing throttle or as you travel up hills and attempt to maintain your speed.

 

if you are just cruising you are in vacuum, no matter what the speed. but if you give it any throttle you will go into boost.

as far as the turbo being on and off, it is always "on" because it has exhaust going though it. but it will only create positive pressure when you are on the throttle.

you are fine cruising at whatever speed you want to.

 

^^well put.

 

Well, it all makes perfect sense now. Thanks!

 

i am going to guess this is your first turbo car?

read up on how a turbocharger works and what your car is doing should me a lot more sense. there is even an evo on the front page of HSW.

http://www.howstuffworks.com/turbo.htm

 

well put....also if you install a boost gauge you will see that as your cruising your in vacuum until you give it throttle

 

Gee, this is embarrassing. For an EVO owner, I’m pretty ignorant about the innards of the motor.

First turbo was a 1989 Plymouth Voyager that made a stunning 97HP. The kids would squeal with delight when the turbo kicked in.

As my second childhood set in, I had these turbos:

2004 Mazdaspeed MX5 (Miata)
2003 Audi TT
2006 EVO GSR SE
2008 EVO GSR Sight & Sound and Aero Kit

Back to when a turbo .is active, I think I have been misled by auto reviews that say “The turbo spools up at 3500RPM”. You are saying that it just happens to spool up at that point because there is lots of exhaust pressure because you have your foot in it, right?

I know the feeling, I had not thought it through. I did know where to go for the correct answer though, huh?

EVO at work: http://www.youtube.com/watch?v=OXmtg2q09P8

 

i want to see a video of that turbo voyager! those thing are badass!

sorry if i insulted by asking if it was your first turbo car, i ment no offence.

when they say "spools by XXXX rpm" they mean that the turbo has reached full boost or the wastegate is opening and bypassing exhaust gas around the turbo so it doesn't create more boost then the desired level. without a wastegate the turbo would continue to create more boost. so when someone says max boost for a turbo they are talking about it's efficiency range not the max number of PSI it will create.

 

See, I learned something new again. On then to a question about a dual-scroll turbo. Just one wastegate? My guess is that the little blades just make a little boost and the wastegate doesn't dump anything until the big ones make a lot.

BTW, no offense taken!

 

dual scroll is referring to the fins on the compressor wheel. it is G wheel (16g turbo) so it has dual scroll. as you go around the compressor wheel there is a pattern of larger and smaller fins... dual scroll. if you look at a 14b from a 1G dsm the compressor fins are uniform. both scrolls are spinning at the same time because they are on the same wheel, they just catch air differently to send it though the compressor housing.

it is completely unrelated to the wastegate which opens and closes to move air around the turbine (hot side) to regulate boost levels.