Posts by Dave@DDMWorks

Attention Vendors. Please email any instruction manuals you may have for your products. They will be added to the FILEBASE tab for members to access.

    Not to revive the dead for no reason... But I too am thinking an exhaust cutout for my turbo application is needed. I love the dual rear 2.5" exhaust I am running now, but know I am being robbed of power. I refuse to change it. So an electronic controlled cut out or boost controlled cutout would be preferred.

    Has anyone completed such? Looking for pointers and what is/isn't working.

    MACAWS   rabtech   Dave@DDMWorks   jaycanter

    rabtech   MACAWS   wokka are all running boost controlled cutouts on their setups that we did here. We have done a lot of these setups now on other Slingshots also, and it works really well since the bypass opens automatically with boost pressure, nothing to forget to do when going full throttle. The 2.5" Welter out the back does start to back things up as you raise boost, but unless you are on a built engine, the 2.5" exhaust will support what power I would put through a stock engine. There is a slight change in air/fuel ratio with the boost activated exhaust cutout on the exhaust, if you have a wideband just make sure to monitor when you make the change.

    Hope that helps,


    Two thoughts come to mind. 1. Ceracoat the top of your pistons to reduce piston head temp by reflecting the heat back to combustion chamber.…6Q/piston-coat-oven-cure/

    All of those pistons are ceramic coated. What we believe happened, based on the datalogs, is that the leaded fuel mix rabtech was running messed with the Oxygen sensors and their readings. We were seeing low 10's air/fuel on the wideband during these runs, but after pulling the spark plugs on both engines, we were definitely not in the low 10's air/fuel. Ghost can confirm, the plugs looked like they were in the 12's at least. Fortunately, it seems that rabtech caught it before things got really bad in the engine :)

    Dave@DDMWorks , I’ll certainly accept lessons . I have spoke to and sent information to the dealership in Savannah to try to get a few local owners interested.
    They talk a mean game of interest. We will see if they put up cash or not. I will check with them again in person in a week or so.

    Just please don’t cancel without giving us a chance to pony up a little more to make this day if we can’t get other SShots signed up.

    Always down to improve my driving game... you teaching Dave@DDMWorks ??

    Right now, me and Zach will be happy to do some instructing, as we both have a lot of experience at Roebling and also in the Slingshots ;)

    The plan is also that we will be bringing our street cars (MINI Cooper S and Supercharged Mazda 2) and taking people in those between the Slingshot groups we run to help show the lines and where people can improve.

    Dave@DDMWorks How much horsepower do you lose at the rear wheel using the 2” welter duals, cat delete, and twist pro headers?

    The difference in power between the supercharger setup for the 2" system and the 2.5" system is around 40-45hp at the wheels. Stock power is typically around 150, the 2" supercharger system usually puts out around 225hp at the wheels and the 2.5" system is right around 270hp at the wheels.

    Also Dave@DDMWorks later on if I were to choose to upgrade to 2.5" welters what would be required to up the HP

    To get the extra power just requires a pulley change and upgrading the exhaust, the tune is the same.

    I think Kyle D once told me he has broken a couple of the shift adapters

    The stock aluminum shift adapter between the transmission and the shift knob does break pretty often. We get calls pretty regularly about it and what is the best solution for it.

    Never seen the actual stock shift knob break like that before though, wow

    I wonder if things would do better if instead of the stock plastic front you tried one of the Voodoo aluminum front bumpers - - - dont know what impact it would have on aerodynamics, but I doubt you would have any bending issues


    That front end is going to reduce a lot of the downforce we are getting with the stock front end at this point. It is also going to allow a lot of air to get up under the hood, creating even more lift on the front. If you sealed off all of those openings though, well that might be better :)

    What!? You ask a serious question in a thread being silly? How dare you!

    My advice, give DDM a call and talk to them about it, or be patient and see if Dave answers here.

    I think the answer is that you need a 2.5" exhaust. You could install a Y and dump it, probably cheaper than buying the Welter 2.5"

    I finally beat you in answering a post, my day is complete :)

    Turbo/ Supercharger question. I have researched the forum and found a answer I believe, but the answer was from several years ago and I was wondering if anything had changed. I talked with Angie back in July about installation the DDM Stage 1 turbo kit and she said the turbo needed a 2.5” exhaust. I know the kit comes with a exhaust, but I like the Welter dual exhaust. My question is, I have the Welter 2” dual exhaust with cat delete and twist pro headers. Can the DDM supercharger kit be used with my current welter 2” setup and be safe and reliable to drive on a daily basics or do I need to change over to the 2.5” exhaust?

    We have a supercharger setup that we have setup for the 2" Welter systems now. You can not make the power of the 2.5" systems, but it is still a nice kick in the pants over stock and lots of fun. Feel free to give us a call - 864-438-4949 we can answer any questions you have on it.

    I thought I would screen grab a shot out of your video and sharpen it up to see if I could see the 1/2 mile marker. Even after I cleared it up you still cant see the 1/2 mile point on the runway.... I have said that I have made fast runs at night on the interstate but never holding my foot to the floor. That is the huge difference. Just letting off the floor a little makes it a much less scary event. The only way to duplicate this run is to go to you local interstate and start at one mile marker and run wide open till you pass the next mile marker. I wouldn't if I were you. But to each his own..... Please video it if you do.... But I'm not telling you to do it... Just sayin...

    That mile mark was a looooooong way ;)

    We have been unloading everything and starting to look over the Slingshot today and noticed something interesting with the front end. Here is a picture of a stock Slingshot front end, at the end of the lower "mustache" you will see that the white upper plastic piece is just a little behind the lower black plastic, about 1/2" -

    We noticed on our Slingshot that the front of our Slingshot was not fitting really well after the event, then noticed how much further back our upper plastic piece is compared to stock, ours is now sitting back about 1" -

    Which is now causing the front end to fit really poorly -

    It is amazing how much force the air pushes on things at these speeds, now to figure out how to correct this.

    I'm not sure if it would be allowed, but I'm sure there's a way to word it to make it pass the sniff test. I have my used Hahn Turbo Stage 2X system (Precision turbo, external waste gate, Billet Blow-off valve etc) listed in the marketplace for sale for $2500 and there has been no inquires so far. I just had a thought. I'm sure there are people who would love to have it, but for one reason or another, the timing isn't right or the cash flow won't allow for a mod of this price range. Would there be any interest in some sort of lottery style drawing for a chance to win this? I would reserve the right to cancel this promotion if less than 20 people bought into it, and would limit the pool of applicants to less than 30 people. For a small fee of $100, you would have between a 3% to 5% chance to win this system (minus the ecu reprogramming). I haven't worked out all the details, but it would be done above board and the winner would have a fully functioning turbo system for less than the price of a set of tires.

    If there's any interests or comments either way, please post them here. If there's no interest in this or the comments are all negative, i will withdraw the idea and ask to have the thread removed from the forum.


    Let me know if you get 2 people interested in the used kit. We have had a used HAHN kit here for a couple months for $2000 and so far, no sale.

    If you do the raffle, maybe we could sell a couple more tickets and have 2 chances to win. :thumbsup:

    Dammn! what were you able to get it up to with that setup?

    630Hp at the wheels, but with the twincharged setup we made 375 ft/lbs of torque at 3000 RPM on a 2.0L and that built to 525 ft/lbs of torque around 5500RPM. Super responsive setup, a ton of fun in something that light with no traction control, ABS, etc.