Forced induction Questions and Such for the Slingshot

    Quote from edwardaneal

    thats interesting to know. I have never had mine on a track and I have never really tried to see how fast it could go, but I have hit 100 very easily on local roads and it always seems like it could easily go much faster when I let off
    I have read that they have the top speed limited, but I do not know if that is true or just speculation

    The 115 MPH was not the top speed of the N/A sling. I believe it was the top speed on that course before he ran out of straightaway and had to turn and let off.


    His point, the charged sling accelerated faster in the same distance to get to the speeds you see in the video.

    John
    2017 SL LE Midnight Cherry
    :COILOVERSS::TURBOSS::MOTOROILSS::FILTERSS::COLDAIRSS::DONKEYSS:

    As far as sticking the rear to the ground..... I have the ability to keep it pretty much stuck to the road.... You just have to bring the boost up a little slower by using your gas pedal. Once you get used to how your bike performs you can control it.. its not that big of a deal... I finally switched over to my boost controller early this morning.... I have been bumping it up and down all day just to see where the sweet spot is when on the highway... And I have found that anything over 12psi for daily driving and passing on two lane roads is just asking to have an accident.... You have to be so attentive to what your doing just to pass a car. If you give it the slightest gas before you are in the passing lane your ass will come loose and slide waaaaaaay out (because your steering that way). . I just get in the other lane and ease on the gas and she instantly goes from 55 to 80 and up.


    I was on the interstate today and it was 96 degrees. I pulled under the underpass in the shade for a min and adjusted my duty cycle on my controller from 35% to 55% and you would have thought I installed a whole 2nd engine beside mine.... I come up the on ramp to the interstate and was right at 100 mph before i got to the interstate. The engine sounded even sounded different. I looked at the boost difference and it added 2 to 3 psi to the 12 psi i was running. That 2 to 3 psi is a huge amount when you add it to 12...


    Im just saying with my Micky Thompson slick and the automatic transmission I can pretty much outrun most sports cars now from a dig to 90mph. Most fast cars will leave you after that. Or that is what I have found to be true.


    I am going to experiment with the boost by gear next week and see how that works.... It should keep some of the wheel spin to a minimum.

    Quote from edwardaneal

    I have read that they have the top speed limited, but I do not know if that is true or just speculation


    I have seen in the ECU something about 165mph . But I can tell you for sure..... The limiter is going to be wind..... Wind is the evil of the slingshot.... And your correct.... You can get to 100mph in a hurry... But just like magic.... after 100mph the wind start holding you back.....


    I believe we need a physics professor to really calculate the drag..... It just feels like it actually starts some sort of drag magnification effect.... Each mph over 100 to 110 it seems like the wind drag is doubled... Or it sure feels like it.... :D

    I rode mine the other week from Albany NY to Buffalo. About a 4 hour ride nothing but highway. SO BORING... until the "kid" in the next car comes up to you doing 80MPH and starts acting as if he wants to race you. Not really sure if his car was boosted, but sure had a lot of stickers of performance shops on the side. Dropped it down to 4th and punched the gas (after making sure I could see ahead for the next mile or two) and the sling jumped to 120. The guy gave up fairly quickly and he was a little dot in my side mirror. Same thing happened with a Porsche the week prior, but was just lucky to keep up with him. I like the power... just wondering if there is any "more" to be gotten out of the Hahn setup. I have NOT switched it to 2X, so I know there is at least an extra 1PSI of boost there, but really don't want to replace my motor and put an end to this years riding season. Just trying to figure out how much more can I push it. According to Jeff Welter, his rear exhaust will handle up toe about a 340 or so HP. It sounds like a 10PSI boost is doable on the stock engine, but nothing is for sure. Just trying to milk the system I got...

    :00000436:
    Success is a lousy teacher. It seduces smart people into thinking they can't lose. - Bill Gates

    Edited 2 times, last by SaltyClownNY ().

    well Im no professor @rabtech but I can tell you , you are exactly right ,'' the limiter is going to be the wind'' IN AIRCRAFT DESIGN WE CALL IT DRAG NOT WIND LOL ,
    but heres the quick lowdown on drag verses speed increases,the drag force on an airplane scales as (velocity)^2 , therefore To double the airspeed you need to quadruple the horsepower , that converts to 100 percent more horsepower required for a 40 % gain in speed . or 100% more horsepower to get a dirty (draggy) airframe to go from 100 mph max speed to 140 mph.max speed.
    So in theory, to increase the speed of a Slingshot from 130 mph max speed to 143 mph max speed you will need to increase HP by 25 % !! OH OH Better call DDM! or just start cleaning up drag .

    @kev thanks for the info.... I could tell that it just seemed like anything over 130 was almost impossible. And that was with high horsepower.


    I think the best money now is in reducing drag by reducing all the spots that catch the majority of the air. I know it's like saying "today were going to make a concrete block light weight and aerodynamic ". :D
    But it cant hurt to reduce some of the obvious wind catchers.

    Quote from kev

    well Im no professor @rabtech but I can tell you , you are exactly right ,'' the limiter is going to be the wind'' IN AIRCRAFT DESIGN WE CALL IT DRAG NOT WIND LOL ,but heres the quick lowdown on drag verses speed increases,the drag force on an airplane scales as (velocity)^2 , therefore To double the airspeed you need to quadruple the horsepower , that converts to 100 percent more horsepower required for a 40 % gain in speed . or 100% more horsepower to get a dirty (draggy) airframe to go from 100 mph max speed to 140 mph.max speed.
    So in theory, to increase the speed of a Slingshot from 130 mph max speed to 143 mph max speed you will need to increase HP by 25 % !! OH OH Better call DDM! or just start cleaning up drag .

    Now that's an image I'd like to get out of my head forever - Rabtech in DRAG!! Thanks Kev, someday I'll return the favor for you and sing it's a small world after all and see if YOU can get that out of YOUR head. :thumbup::thumbup::thumbup:

    Nobody gets outta here ALIVE

    Quote from funinthesun

    Now that's an image I'd like to get out of my head forever - Rabtech in DRAG!! Thanks Kev, someday I'll return the favor for you and sing it's a small world after all and see if YOU can get that out of YOUR head. :thumbup::thumbup::thumbup:

    Let me help you with that image!!

    DID SOMEBODY SAY MORE HORSEPOWER?!?!

    :BLACKSS: 2016 SL LE BLACK PEARL :HEADERSS::COLDAIRSS::COILOVERSS::MOTOROILSS::OILFILTERSS:

    has anyone seen anyone tried or seen the Procharger set up for the SS,? ..if I was going to use a blower In a SS I would feel more comfortable using a product from a brand I’ve used in the past with zero issues,and has the great track record on many types of vehicles ...


    I’ve never had a blown 4cyl ,and normally it’s true a blower generates more torque at a lower Rpm and is able to carry it flat throughout the curve ...
    While turbos are able to build more more total power due to less parasitic loss at the same psi..so to see the Hann turbo graph I think it was making more power sooner was eye opening and made me think..


    I’m guessing that it might be because of the drag and that a 4cyl just doesn’t make enough power down low to over come it..? Anyone have any insight to any of this..I know some newer types of S/C’s have very little drag compared to those it takes both hands to turn ,lol..

    Quote from Gnx1234

    has anyone seen anyone tried or seen the Procharger set up for the SS,? ..if I was going to use a blower In a SS I would feel more comfortable using a product from a brand I’ve used in the past with zero issues,and has the great track record on many types of vehicles ...


    I’ve never had a blown 4cyl ,and normally it’s true a blower generates more torque at a lower Rpm and is able to carry it flat throughout the curve ...
    While turbos are able to build more more total power due to less parasitic loss at the same psi..so to see the Hann turbo graph I think it was making more power sooner was eye opening and made me think..


    I’m guessing that it might be because of the drag and that a 4cyl just doesn’t make enough power down low to over come it..? Anyone have any insight to any of this..I know some newer types of S/C’s have very little drag compared to those it takes both hands to turn ,lol..

    We had the chance to see one out in Vegas at SEMA last year. They did a pretty good job with their setup and are using a dedicated belt for the supercharger like our kit. We have supplied some upgardes to several of the Procharge kit owners now and with the upgrades, they seem to be a nice kit. Their kit does not compare to the power of our kit or the midrange though, do to the big differences in the actual superchargers themselves. For a nice boost in power and if you want a "brand" name, it seems to do the job.


    The superchargers that are available for the Slingshot right now are centrifugal superchargers, which build boost exponetially with engine RPM. That is why you are seeing lower boost with the superchargers at lower RPM's and higher boost at higher RPM's. That being said though, there is still a bump in power down low and by 3500RPM the superchargers are really starting to make good power and torque. As for the power required to run the superchargers, the centrifugals do a really good job at being efficient and also having good adiabatic efficiency also. the Rotrex unit we use is peaking around 70% in the heart of the midrange torque area of the engine, very similar to most of the turbos.


    Hope that helps,
    Dave

    Has anyone seen a wind tunnel test done ?


    Has anyone seen kits to fill in the big open areas in the front or kits to redirect any airflow ?


    Is there any prove that those rear wings even generate any down force that Benefits it at a speed

    Quote from Gnx1234

    Has anyone seen a wind tunnel test done ?
    Has anyone seen kits to fill in the big open areas in the front or kits to redirect any airflow ?


    Is there any prove that those rear wings even generate any down force that Benefits it at a speed

    Wind tunnel test DONE... sure. Was doing work with Boeing with their digital photograph department and they have a tunnel. Done with a Slingshot... nope. Most add ons I would think would increase weight and drag. I do know @WrongWheelDrive cracked his wing on his slingshot by doing over 120 MPH with it. Not sure how much down pressure you need to crack it, but was enough to crack.


    Problem I see with the wings is sure, there is probably down pressure the faster you go, but I see the issue being that you need more down pressure at slower speeds... or that is my totally uneducated theory.


    Thanks @rabtech for the info. I guess I have to go back to my MT rear wheel for a bit. I can say that they just repaved my road in front of my house and the soft asphalt really works well for sticking your wheel LOL. That and if I blow the engine I can turn into my driveway real quick smile-squared

    :00000436:
    Success is a lousy teacher. It seduces smart people into thinking they can't lose. - Bill Gates

    Well that's a frikin bummer... Was hoping to see you.
    OK, I will wait until winter hits to send in the ECU.

    DDM Stage 2 SuperCharger
    1320 Manifold
    WP Dual Exhaust
    Custom Blue /w ghosting

    Just finished up installing the DDM supercharger today on my 16.5. I have about 100 miles on it so far. Quick question for you supercharger guys. Is it normal that the cockpit temps significantly increase after the install? Did the removal of the rear radiator shroud effect this? Also, I know the ECU is still learning but I am getting a sort of fluttering sound from the exhaust at idle. Just trying to figure out what is normal and what is not? New to the world of boost. Also like to thank @Casey_SS for all his help with the Install. @TravAZ and @Ghost had me covered with all the pre install questions. I sincerely appreciate it guys. Thank you.

    Quote from NJ SS

    Just finished up installing the DDM supercharger today on my 16.5. I have about 100 miles on it so far. Quick question for you supercharger guys. Is it normal that the cockpit temps significantly increase after the install? Did the removal of the rear radiator shroud effect this? Also, I know the ECU is still learning but I am getting a sort of fluttering sound from the exhaust at idle. Just trying to figure out what is normal and what is not? New to the world of boost. Also like to thank @Casey_SS for all his help with the Install. @TravAZ and @Ghost had me covered with all the pre install questions. I sincerely appreciate it guys. Thank you.


    @NJ SS determined his sling was asthmatic and needed breathing assistance


    The picture below is prior to the surgical implantation of the Rotrex fire breathing apparatus.
    Surgery was performed in @Casey_SS Operating Room!



    John
    2017 SL LE Midnight Cherry
    :COILOVERSS::TURBOSS::MOTOROILSS::FILTERSS::COLDAIRSS::DONKEYSS:

    Quote from Dave@DDMWorks

    We are not coming to the Ozarks unfortunately, we are all booked up for September and just can not make that event, sorry. If you want to send the ECM to us, we can flash it here though or you can send it straight to Bob.

    Dave< What is the cost to go from the original supercharger flash to the new one with less throttle hang? Besides the ECU,what do you need.....exhaust specs, pully size etc. Thanks