User Tag List

Results 1 to 12 of 12

Thread: 6th gear, 2000rpm bad, full throttle, bad?

  1. #1
    Join Date
    Mar 2009
    Location
    Sydney
    Age
    38
    Posts
    464

    Default 6th gear, 2000rpm bad, full throttle, bad?

    Hey hows it going. Read somewhere that someone was saying that going full throttle in 6th gear at 2k rpm was stupid and the driver was a "so and so" for doing it.

    I know it can't be good and i wouldn't do it myself, but whats the reason behind it? Added strain on the engine, but how? Would it make the boost shoot through the roof?

  2. #2
    Join Date
    May 2009
    Location
    The East Island (Neu Zulund)
    Posts
    714

    Default

    ???

    i dont see the issue...

    even if you ful throttle the car at low RPM in a high gear.. its not like your going to be able to dump excess amounts of fuel in there.. as the ECU has full controll over the injectors and the throttle flap..???

    its prob all just heresy..

    one thing ive learnt with the internet.. dont beleive 98% of anything

  3. #3

    Default

    Hmm, sounds like a load of BS to me. If an engine cant handle a full throttle load across it's full rev range, then it's a pretty crap engine. I regularly, put my car in 6th and put the cruise control on at 60km\h. It uses less fuel. I've even had it down to 40km\h through a roadworks area, it sits on abnout 1100RPM and pulls just fine... uses less fuel than any other gear. It can accelerate fine from 40 to 60 in 6th as long as your not in a hurry. Whats the point of having an engine with so much torque down low if you cant use it?

  4. #4
    Join Date
    Nov 2008
    Location
    Craigieburn
    Age
    50
    Posts
    1,642
    Blog Entries
    1

    Default

    The concern in this circumstance is knock and the wear and tear that knock can induce. Low speed high gears can be quite prone to it.
    Personally, I wouldn't use 6th gear at speeds less than ~80
    You may even find that 5th gear at 60 is more economical that 6th because the ECU doesn't create quite as rich mix (to prevent knock)
    Wide open throttle in high gear overloading the engine not a great idea. You will find in economy driving how-to's that they say NOT to allow the engine to labour.
    1500rpm, 6th gear, wide open throttle will labour. Badly.

  5. #5
    Join Date
    May 2009
    Location
    The East Island (Neu Zulund)
    Posts
    714

    Default

    fair commment.. but at the end of the day... nothign is built to last knock or no knock she will wear out.. but that wont be in my time of owning the car... suppose i turn over cars relativly quickly thou..

  6. #6
    Join Date
    Dec 2008
    Location
    Sydney
    Age
    49
    Posts
    1,834

    Default

    For the non believers out there, give it a go....go out and drive your car in 6th gear at 2k rpm, or less and floor it (quickly), the stuttering that you will most likely feel is the ECU retarding timing to prevent it from knocking holes in its pistons.

    As far as being a poorly (crap) designed engine if it knocks under these circumstances, go buy a v8, you obviously have no idea about turbocharged motors.

  7. #7

    Default

    Quote Originally Posted by MattMPS3 View Post
    As far as being a poorly (crap) designed engine if it knocks under these circumstances, go buy a v8, you obviously have no idea about turbocharged motors.
    I'm guessing this is aimed at me. Sorry if I offended, the point I was trying to get across is that these engines are not crap, and I am yet to notice any retarding as you have described. I have a Bluebird with a fairly modified SR20DET in it. Doing the things I said in the above post in this car would surely cause issues. I don't see it as a problem in the mazda, the direct injection overcomes the knocking. At 1500RPM, I wouldn't think that the turbo would be pushing any boost at all, so essentially at these lower revs, it's an NA engine.

    Using 6th gear to accelerate from speeds that low would deffinately not be economical, but with the cruise control on at a constant speed it does use less fuel.

  8. #8

    Default

    FYI...

    5th and 6th gear use the same final drive ratio....different from 1st to 4th.

    So...you should be using 5th gear...not 6th...

    As it doesnt make any difference....they are both economy gears.

    As for doing WOT on low revs

    I drive around the city/burbs in 5th...and save 6th and c/control for the hwy only.

    Happy Motoring
    duglet

  9. #9
    Join Date
    May 2009
    Location
    The East Island (Neu Zulund)
    Posts
    714

    Default

    how about we drive our cars how we want...? who really cares lol... i know i dont...

    Who really gives a shit if they blow up in a year or two.. MPS ownership tends to be high turnover any way... tbh im already selling mine as ive done 20,000kms in it already..

  10. #10

    Default

    I have 94000kms in mine...and its still going strong like the first day i bought it

    Happy Motoring
    duglet

  11. Default

    Quote Originally Posted by Ante View Post
    Who really gives a shit if they blow up in a year or two.. MPS ownership tends to be high turnover any way... tbh im already selling mine as ive done 20,000kms in it already..
    Yeah, I sold mine at 22k on the clock.

    As for flooring it in 6th gear at 2000 RPM, it does strain the engine, but I doubt if it would do any harm, unless you've got any major modding.

    I had concerns with mine, travelling at 100km/hr HWY with cruize control on (sitting on around 2200 RPM) in 6th. Pushing the cruize ACC button would cause a turbo spike, and it felt like the motor was under so much strain it was going to blow... I never saw any knock retard or alerts on the Dashhawk, no boost cut or fuel cut either, but it just felt wrong...

    Some others have commented the same (with modded MPS's) in another thread... In any case, if its stock, and you floor WOT it, and she blows, warranty will cover you (providing you're still within the warranty period). I have yet to hear of any stock MPS's blowing. In fact they shouldnt, because Mazda would have beat the b1tch hard in testing.



    ---------- Post added at 08:15 PM ---------- Previous post was at 08:13 PM ----------

    Quote Originally Posted by duglet View Post
    I have 94000kms in mine...and its still going strong like the first day i bought it
    And without any mods
    Last edited by Wardski; 26-07-2009 at 08:17 PM.

  12. #12

    Default



    I have 2 minor mods

    Happy Motoring
    duglet

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •