is it bad to cruise in boost?
for example.. on the highway going 180km/h in 5th gear..
when my car was NA i would sit at 180-200 with no problems (though the car drank fuel... but thats not the issue here) for minutes at a time on road trips occasionally slowing down to around 150 if the road got twisty....
.. but im not sure if i would be putting too much stress on my engine if i was doing those same speeds but at boost.. i notice the car does warm up a bit when i boost in 5th because i can feel it thru the vents, but the engine temp stays stable.. i think i smell something though, oil, gas, i dunno..
im thinking a longer 5th gear might give a safer high cruise speed..
ur thoughts?

 

Problems with sustained high-gear boosting is oil temp increase, as well as heatsoak-like problems - valves getting too hot, turbine glowing, etc. Chances are your ems is set to retard timing based on gear, so you're adding to the exhaust heat problem.

 

increase in oil temp.. makes sense and would also explain what im smelling.. so would an oil cooler solve that and permit longer endurance high gear boost?

 

..?

 

if you are just cruising you shouldn't be in boost at (no matter what speed). if you are doing a pull up to that speed there really shouldnt be a problem as long as its tuned right. but as stated above heat can start to become a problem. and not to preach cause highway pulls are fun, but cruising at 112-125mph is kinda scary. isnt there a speed limit?

 

well if theres a long hill you most likely have to be boosting to maintain freeway speed. espically if you have a smaller turbo. when i had the stock turbo on my evo it would boost all the time. i can be driving normal shifting at 3krpm and it would still be boosting. every time i hit a hill on the freeway i'll boost at least 5psi just to maintane 80mph.

if the tune is good and the engine is strong (not stock internals) you should have no probably doing wot pull in 5th gear all day long

 

to maintain a specific speed your engine only needs a specific power...so it's no more stresfull than doing it N/A

 

You won't be in boost while "cruising". Boost kicks in depending mostly on vacuum and partly speed/RPM.

 

http://www.merriam-webster.com/dictionary/cruising
Cruise: intransitive verb "to travel at a speed suitable for being maintained for a long distance"

By definition it is impossible to boost while cruising because their must be a load i.e. acceleration for there to be boost. So you'll be fine

 

why the hell would you be cruising at 180-200 km/h?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HybridEL &raquo;</TD></TR><TR><TD CLASS="quote">why the hell would you be cruising at 180-200 km/h?</TD></TR></TABLE>

What? You don't cruise at 120mph?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HybridEL &raquo;</TD></TR><TR><TD CLASS="quote">why the hell would you be cruising at 180-200 km/h?

</TD></TR></TABLE>

hahahaha

 

it should be on vacuum when cruising on flat road.

 

why the hell are you "cruising" at that speed...

dude.. i cruise at like 130km/h most of the time, and occasionally higher... why you need to go that high is beyond me..

and like they said.. if its CRUISING, then there is no load, and u shouldnt be boosting at all..

 

get a bigger turbo

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Topdawgg &raquo;</TD></TR><TR><TD CLASS="quote">why the hell are you "cruising" at that speed...

dude.. i cruise at like 130km/h most of the time, and occasionally higher... why you need to go that high is beyond me..</TD></TR></TABLE>

Maybe some people would say "Why the hell are you cruising at 130km/h?" If it's a nice highway, and no traffic, who are you to judge? Going 180-200km/h isn't a big deal, if conditions permit that kind of speed.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dpetro1 &raquo;</TD></TR><TR><TD CLASS="quote">if you are just cruising you shouldn't be in boost at (no matter what speed). if you are doing a pull up to that speed there really shouldnt be a problem as long as its tuned right. but as stated above heat can start to become a problem. and not to preach cause highway pulls are fun, but cruising at 112-125mph is kinda scary. isnt there a speed limit? </TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DC4KiD &raquo;</TD></TR><TR><TD CLASS="quote">You won't be in boost while "cruising". Boost kicks in depending mostly on vacuum and partly speed/RPM.</TD></TR></TABLE>

ya if were cruising at 120 then maybe u could avoid being in boost, try cruising at 6k rpm u cant let off the throttle n fall out of boost ANDstay at 6k rpm.. to rev that high significant throttle is applied and YOU ARE IN BOOST.. (try it) everytime i let off the throttle a bit going 160 at "cruise" i hear a pssht from my BOV..
yes there is a speed limit.. those doing it should stay to the right and let me pass them.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HybridEL &raquo;</TD></TR><TR><TD CLASS="quote">why the hell would you be cruising at 180-200 km/h?
</TD></TR></TABLE>

to get where im going faster...

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted k20 &raquo;</TD></TR><TR><TD CLASS="quote">get a bigger turbo</TD></TR></TABLE>

how does that help?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Sprockets &raquo;</TD></TR><TR><TD CLASS="quote">

Maybe some people would say "Why the hell are you cruising at 130km/h?" If it's a nice highway, and no traffic, who are you to judge? Going 180-200km/h isn't a big deal, if conditions permit that kind of speed.</TD></TR></TABLE>

thank you

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted k20 &raquo;</TD></TR><TR><TD CLASS="quote">get a bigger turbo</TD></TR></TABLE>

Yup sound like to much back pressure from a small turbo. That will also lead to reversion and higher engine temps.

 

What's with the idiots saying it's impossible to be in boost while 'cruising'. No load? Lay off the drugs, of course there is a load it's called WIND RESISTANCE. To maintain 200kph there is a MASSIVE force against the face of the car, so much that OF COURSE it is possible that for the particular engine in question to be in boost to produce that much power.

 

I want to run a gt40r on a 500-600whp b20, just to keep intake temps down in boost. Mainly for 'cruising' at high speeds..

Ive also thought about putting a small oil cooler on the turbos drain line, thinking that most of the heat in the oil is coming from there. I could be wrong though, and dont really want an oil cooler all the time keeping the oil TOO cool..

 

Most of the heat imparted to the oil is courtesy of the pistons, supposedly. Although obviously the turbo does heat the oil, I can't say by how much. An oil cooled turbo under boost will also cause continuous damage to non synthetic oil, (to cite "Maximum Boost") too. (even with a cooler) I would say an oil cooler is a necessity for a motor that sees high loads for any significant amount of time.

I've wondered about this subject before, but never really figured anything out. I know some racing airplane motors boost for like 20 minutes at a time under incredibly hard conditions, (air cooled motors too) but I don't know what usually breaks first when something finally does. I know with cast pistons, heat will definitely weaken them. I believe that's why despite being n/a, the vtec motors have oil squirters. I wonder what it would take to get the pistons hot enough to burn the oil, even with a cooler, or if they'd expand so much they'd scuff or seize in the cylinders, or if the rings would expand so much they'd do the same? I imagine if you were building a motor knowing it was going to see continuous boost, you'd use larger piston/cyl wall and ring gap clearances, a good oil cooler, and make sure it couldn't overheat.. I'd also modify the pcv system and set it up to draw fresh air through the crankcase under boost so your oil wouldn't go to **** in 500 miles.

Another thing I just thought of..boat motors. They definitely see high loads for extended time. I wonder what people do to their turbo boat motors to get them to last. Obviously a near infinite supply of cool water for cooling doesn't hurt, but still..

 

i have to figure something out because i dont feel safe pushing my car past 180 anymore even for short bursts.. im getting passed by guys in wrx's and i used to pass them on the highway at top speed when i was n/a ..
is there any way to decrease the boost in 5th gear?

 

driving 180km/h in an EF on a regular basis? i dont want to see pictures of your car wreck.

 

He's more than likely on Highway 401 or 400 if in Ontario. (Am I right on this?) That is about 111mph. I drove those speeds going through London/Missasagua/Hamilton area. Even the cops there don't do much, but strangely enough, if you're from the states, have an exhaust or some way of making the car "different" you get profiled and pulled over for no reason IMHO.

I've driven just outside of "load" in a boosted honda at those speeds. Regardless, the turbo is still technically spooling, just not gaining positive pressure. I've found that my fuel economy actually got BETTER when I was just outside that load range, due to the increased atomization of fuel with the turbocharger, but when in LOAD, like going up a hill, or anything else, it depends upon the speed maintained. As long as your engine temps stay normal and you always "check oil", there shouldn't be a problem.

 

Actually cops are cracking down now in TO, they just put in a law 50km+ over the limit is an automatic vehicale seizure and 10K$ fine... the limit is 100km/hr or ~60mph. And they prey on anyone with a modded car

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TheShodan &raquo;</TD></TR><TR><TD CLASS="quote">He's more than likely on Highway 401 or 400 if in Ontario. (Am I right on this?) That is about 111mph. I drove those speeds going through London/Missasagua/Hamilton area. Even the cops there don't do much, but strangely enough, if you're from the states, have an exhaust or some way of making the car "different" you get profiled and pulled over for no reason IMHO.

I've driven just outside of "load" in a boosted honda at those speeds. Regardless, the turbo is still technically spooling, just not gaining positive pressure. I've found that my fuel economy actually got BETTER when I was just outside that load range, due to the increased atomization of fuel with the turbocharger, but when in LOAD, like going up a hill, or anything else, it depends upon the speed maintained. As long as your engine temps stay normal and you always "check oil", there shouldn't be a problem.</TD></TR></TABLE>