Power upgrade on race car





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  1. #1
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    Default Power upgrade on race car

    Applying the philosophy that more is indeed more and wanting to chase some seriously fast race cars (Ligier's, Shelby's and ADR's) which have aero meant that my Lotus 7 race car "needed" a turbo upgrade.

    Engine is a stock SR20VET (pretty rare engine out of an Xtrail GT that was only sold in Japan), stock power is 280HP (210kw) so already not short of power. I raced the car like this for a year before upgrading to a Garrett GT3076R turbo late last year. Work and family pressure meant I only finished the upgrade this year and I recently had the car with Stephan to apply his magic on the dyno. Car runs spitronics which he does not like but he did a fantastic job spending time on part throttle before doing power runs.

    The engine is still stock but I am however running on high octane fuel and water meth injection to control detonation and keep the temperatures in check. It was also probably the perfect day for a dyno, cool rainy conditions meant the engine had some nice dense air to breathe. The turbo comes on boost very aggressively so completely unsuited for a road car and we will have to see how it behaves on track. My logger will limit boost to 0.7 bar in the lower gears and only allow 1bar in 4th and 5th gear. Car with my fat arse in it weighs 680kg

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    Nothing screams "Bad workmanship" like wrinkles in the duct tape

    2012 Q7 4.2 TDI
    Birkin SR20VET race car


  2. #2
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    Default Re: Power upgrade on race car

    366kw op die wiele in 'n Lotus 7.

    Jy gaan staal knaters nodig he.
    My name is Rainier and I drive a Frotuna.

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  3. #3
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    Default Re: Power upgrade on race car

    Awesome thanks for sharing
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    Default Re: Power upgrade on race car

    Hy maak mooi
    It is not what you buy its what you build.

  5. #5
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    Default Re: Power upgrade on race car

    That must be a really big turbo. Power is coming on late in the rev range. Hows that going to be on track? Will need to keep the revs high to remain in the power band.
    Its not about how fast you are but about how quick you get there...


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    Default Re: Power upgrade on race car

    Quote Originally Posted by Die$eL View Post
    That must be a really big turbo. Power is coming on late in the rev range. Hows that going to be on track? Will need to keep the revs high to remain in the power band.
    Its a GT3076, stock turbo was a GT25 so its a substantial upgrade. Stock turbo came on boost around 3000 rpm but peaked around 5000 rpm and the torque really dropped off from 5500 because it could not maintain boost all the way to the limiter. New turbo only starts spooling from 4500 but torque peaks at 5800 and it maintains boost all the way to the limiter, the big power gain was the ability to main 1 bar boost at high rpm. So like most things in life its a compromise

    Keeping the car in boost in really slow corners will be a challenge (2nd gear stuff like T2 at Zwartkops) anywhere it should be fine. Ideally I need a close ratio sequential box, but thats not going to happen
    Nothing screams "Bad workmanship" like wrinkles in the duct tape

    2012 Q7 4.2 TDI
    Birkin SR20VET race car


  7. #7
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    Default Re: Power upgrade on race car

    can buy a new car for the price of a sequential box
    Its not about how fast you are but about how quick you get there...


  8. #8
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    Default Re: Power upgrade on race car

    Paint it orange
    Range Rover Sport 5.0 SC
    Lotus 7 replica racecar.
    Ex R5 Touareg with air and RDL

  9. #9
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    Default Re: Power upgrade on race car

    Quote Originally Posted by Hamtheman View Post
    Paint it orange
    orange is the lotus days, new series new colours
    Nothing screams "Bad workmanship" like wrinkles in the duct tape

    2012 Q7 4.2 TDI
    Birkin SR20VET race car


  10. #10
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    Default Re: Power upgrade on race car

    I know, just reminiscing.....
    Range Rover Sport 5.0 SC
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    Ex R5 Touareg with air and RDL

  11. #11
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    Default Re: Power upgrade on race car

    Some serias power....well done
    Range Rover Sport 5.0 SC
    Lotus 7 replica racecar.
    Ex R5 Touareg with air and RDL

  12. #12
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    Default Re: Power upgrade on race car

    Finally got to run the car at the track this weekend. Red Star is not an ideal track with lots of really slow corners plus the car suffered from intermitted misfire at high rpm for most of the weekend, tried everything but only dropping the boost would make it go away. Ran first race at 0.7 bar and the second at 0.9 bar. Stupid race camera did not work so missed out recording an epic battle with Ian in his turbo shelby, ultimately he was faster than me but he started behind me and I could outdrag him on the straights so managed to keep him at bay.

    The only way I can describe the car is brutal, keep it above 5000 rpm and this thing accelerates like a madman. we do not do standing starts so cant give 0-100 times, but I do have rolling acceleration data from my logger:
    60-160 km/h in 3.9 seconds
    60-220 km/h in 9.2 seconds

    to put that into perspective a Ferrari 458 will do 60-160 in 3.7 seconds and a Veyron in 3.6 seconds both with a dual clutch boxes while I run a stock H pattern manual box.

    need to work on the setup and sort out the misfire, but Phakisa in April is going to be epic!
    Nothing screams "Bad workmanship" like wrinkles in the duct tape

    2012 Q7 4.2 TDI
    Birkin SR20VET race car


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  14. #13
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    Default Re: Power upgrade on race car

    Direction at Redstar and lap times?
    Errol Cornelius



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    Default Re: Power upgrade on race car

    Quote Originally Posted by zx14 View Post
    Direction at Redstar and lap times?
    anti clockwise, got down to a 2:03
    Nothing screams "Bad workmanship" like wrinkles in the duct tape

    2012 Q7 4.2 TDI
    Birkin SR20VET race car


  16. #15
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    Default Re: Power upgrade on race car

    Nice!
    Errol Cornelius



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  17. #16
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    Default Re: Power upgrade on race car

    have you tried reducing the plug gaps?
    The higher boost could be blowing the spark off. I had a similar issue on my MR2 previously.
    Its not about how fast you are but about how quick you get there...


  18. #17
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    Default Re: Power upgrade on race car

    Quote Originally Posted by Die$eL View Post
    have you tried reducing the plug gaps?
    The higher boost could be blowing the spark off. I had a similar issue on my MR2 previously.
    Thanks, I have been advised that as well. Will be trying that before the next race
    Nothing screams "Bad workmanship" like wrinkles in the duct tape

    2012 Q7 4.2 TDI
    Birkin SR20VET race car


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  20. #18
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    Default Re: Power upgrade on race car

    Quote Originally Posted by zx14 View Post
    Nice!
    Similarly powered 7 got down to 2:01's so need to put on my big boy pants next time out.
    Nothing screams "Bad workmanship" like wrinkles in the duct tape

    2012 Q7 4.2 TDI
    Birkin SR20VET race car


  21. #19
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    Default Re: Power upgrade on race car

    Quote Originally Posted by mullerza View Post
    Its a GT3076, stock turbo was a GT25 so its a substantial upgrade. Stock turbo came on boost around 3000 rpm but peaked around 5000 rpm and the torque really dropped off from 5500 because it could not maintain boost all the way to the limiter. New turbo only starts spooling from 4500 but torque peaks at 5800 and it maintains boost all the way to the limiter, the big power gain was the ability to main 1 bar boost at high rpm. So like most things in life its a compromise

    Keeping the car in boost in really slow corners will be a challenge (2nd gear stuff like T2 at Zwartkops) anywhere it should be fine. Ideally I need a close ratio sequential box, but thats not going to happen

    I'm totally out of my depth here.... but what about a variable vane turbo ?
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  22. #20
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    Default Re: Power upgrade on race car

    Quote Originally Posted by 280iNyati View Post
    I'm totally out of my depth here.... but what about a variable vane turbo ?
    Remember this is an extremely niche setup. In a road car, even a performance orientated road car the engine must be usable through its whole RPM range for everyday use. On a race car I do not care at all about power delivery at low to mid RPM. The engine is always screaming at full throttle or I'm on the brakes with very little in between.

    Variable vane turbo requires a much fancier engine management system than I have to control. Also in a race car application where I'm never below 4000rpm the benefit of a variable vane will never be worth the added cost and complication.
    Nothing screams "Bad workmanship" like wrinkles in the duct tape

    2012 Q7 4.2 TDI
    Birkin SR20VET race car


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