Question on Exhaust Modification for more Horsepower

    I Talked with Welter on the duals for the turbo they say it's good for about 300 hp anything above need to add an boost controlled exhaust cut-out.I have the Hahn Turbo with side exit exhaust.


    What i am looking to do is pipe the waste gate out of the side exit rear hole, then install a boost controlled cut-out run thru muffler and out the 1st side exit hole.


    What i am trying to figure out what size to go with on the exhaust cut-out? The Welter is 2.5" and good for around 300.
    The exhaust cut-out will be piped on the drop off of the turbo, thru a magnaflo race muffler and a side exit tip so total lenght it will be around 1-1/2 to 2ft long run trying to find out how small of the pipe can be. for 200hp to 300hp range. can i use 1-1/2 or 2" or 2-1/2


    Thanks For any input or has anyone else started exhaust something like this


    planning ahead for ddm built motor just trying to get exhast worked out before motor.

    @jaycanter
    I am running the side exhaust on a Hahn with a DDM Built motor and getting 385 hp
    If I could open the exhaust up I would definitely be in the 430 plus range. I think with all the extra piping the Welter would be even more restrictive. But if you are going to set up a dump
    I would try it with what you have now (I am considering something similar)
    I just think before you dump 2K on a new exhaust fist see if you like the concept working with what you have.

    The more people I meet

    The more I love my Dog!

    @MACAWS i already purchased the Welter exhaust to replace the Hahn side exit. Welter said anything over 300 hp needs exhaust cut-out, I'm gonna try to draw on the pic out what i am doing (once i figure out how to do it)


    End result exhaust out back queit then when needed the exhaust cut out and waste gate both on separate mufflers running where the old hahn did out the sides

    @MACAWS has the Hahn side exit at about 400hp. Since the Welter exhaust is a bit longer and a bit smaller you are correct. You will need to weld in a dump or "boost operated cutout" to get more than 300hp. You can get actually get more than 300hp out of the Welter it just won't spool up as quuck. I think Noel hit the peak with it at about 325 to 350hp. Basically 2.5" will be fine as a dump for both exhaust and wastegate since they will be a couple of feet long.


    I am going in January to DDM to do the same thing kinda. I am going to use 3" dump on the exhaust and 2.5" on the wastegate due to my craving for getting WELL into the 500hp range. However I don't think this is achievable with the stock fuel system. I have no faith in the fuel pumps ability to deliver consistent fuel at that high of a hp. So what I will probably end up with is 450hp that runs very very smooth..


    You can get to 400hp without having a ton of pain. IT is when you start hitting 430 470 500 that it seems you start flirting with all kinds of weird issues. Fueling being a big big issue. I have seen mine make monstrous pulls on the dyno one minute and then on the next pull have to get out of it because it is dipping toward being to lean. And that is fine and dandy when you are staring at the guage. On the highway you don't have that option of being able to watch the gauge. Their is no tune that will allow the safe and consistent use of a boost controller. I would say that 375hp with a built engine will keep the heartbreak factor to a minimum... At least till there is a way to add more fuel or have a boost controller that will dial the boost back when it's lean.

    Quote from jaycanter

    @MACAWS i already purchased the Welter exhaust to replace the Hahn side exit. Welter said anything over 300 hp needs exhaust cut-out, I'm gonna try to draw on the pic out what i am doing (once i figure out how to do it)


    End result exhaust out back queit then when needed the exhaust cut out and waste gate both on separate mufflers running where the old hahn did out the sides

    Now that sounds like an interesting plan - can't wait to see the final product

    The more people I meet

    The more I love my Dog!

    So just wondering... If and when I ever get that big Kahuna pack from @Jeff@DDMWorks, would a built motor be required? I won't be doing racing, dynos pulls, or looking to top out HP... Just want a SC, headers, and exhaust for speed when I'd like it... Can the stock engine handle this without being at risk? Or should I say, is there an estimate for the percent chance of blowing it, stock vs the add ons I listed?


    Again, no racing or HP quest, just crazy driving every now and then...

    Quote from MiM

    So just wondering... If and when I ever get that big Kahuna pack from @Jeff@DDMWorks, would a built motor be required? I won't be doing racing, dynos pulls, or looking to top out HP... Just want a SC, headers, and exhaust for speed when I'd like it... Can the stock engine handle this without being at risk? Or should I say, is there an estimate for the percent chance of blowing it, stock vs the add ons I listed?


    Again, no racing or HP quest, just crazy driving every now and then...

    @MiM I don't know of an estimate for blowing your motor with the supercharger....... How UN lucky are you? When I purchased the supercharger I spoke with the guys at DDM and they explained to me that this setup has been tested with no problems. I don't have the miles on mine that they do but for over 1000 miles I have not had a problem. The bad thing is that the crazy driving comes more often than you would think. When you mash the go pedal and that lil 4 cylinder comes alive, it will put a big smile on your face.

    :BLUESS:
    Twenty years from now you will be more disappointed by the things you didn't do than by the ones you did do.
    ~Mark Twain~

    Here's some pics of what i am trying to do (had a heck of a time trying to draw captions on the pics). I am shooting for 400 to 500 hp range if possible. I know there is a fuel pump option and the Haltech but i am trying to reuse the holes for side exit if possible for waste gate and exhaust cut-out if doable with that kind of power instead of just dumping underneath like the existing waste gate muffler. Both the waste gate and the Exhaust cutout will be piped separately. @rabtech should i bring the waste gate up from the 1-1/2" of the Welter to 2-1/2 by itself?

    Quote from Rob the Slob

    @MiM I don't know of an estimate for blowing your motor with the supercharger....... How UN lucky are you? When I purchased the supercharger I spoke with the guys at DDM and they explained to me that this setup has been tested with no problems. I don't have the miles on mine that they do but for over 1000 miles I have not had a problem. The bad thing is that the crazy driving comes more often than you would think. When you mash the go pedal and that lil 4 cylinder comes alive, it will put a big smile on your face.

    What he said @MiM. You're going to be on it more than not... believe me. It's addictive once you feel that power. After a while you'll reach a point where it's not enough and you start wanting and looking for more. Grant it, I'm Turbo, not SC, but same effect. I've been told by several individuals and have read several places that these engines can handle the 300 hp pretty reliably (most of them can). Anything above that you're going to have to follow @rabtech, @MACAWS, .... etc lead on engine mods. I'm Already looking into that :thumbup: .... It's just never enough :(

    Quote from MiM

    So just wondering... If and when I ever get that big Kahuna pack from @Jeff@DDMWorks, would a built motor be required? I won't be doing racing, dynos pulls, or looking to top out HP... Just want a SC, headers, and exhaust for speed when I'd like it... Can the stock engine handle this without being at risk? Or should I say, is there an estimate for the percent chance of blowing it, stock vs the add ons I listed?


    Again, no racing or HP quest, just crazy driving every now and then...

    The Built Engine is not required. We would not sell you something unsafe. The DDMWorks Rotrex supercharger kit is controlled by the pulley size on the rotrex supercharger. We will send you the rotrex with the correct pulley size already installed for your stock engine.

    Jeff Mellor
    DDMWorks
    119A Highway 183
    Piedmont, SC 29673
    Orders - 864-438-4949
    Tech Support - 864-907-6004
    www.DDMWorks.com

    Quote from Rob the Slob

    @MiM I don't know of an estimate for blowing your motor with the supercharger....... How UN lucky are you? When I purchased the supercharger I spoke with the guys at DDM and they explained to me that this setup has been tested with no problems. I don't have the miles on mine that they do but for over 1000 miles I have not had a problem. The bad thing is that the crazy driving comes more often than you would think. When you mash the go pedal and that lil 4 cylinder comes alive, it will put a big smile on your face.

    I'm going to agree with Rob and add this... I don't care now how many times I tell myself I'm going to drive normal... I can't do it since I've boosted it! It is like a contest to see if I can make it go "WHOOOSH". Maybe it will wear off... 500 miles so far Alpha SC boosted... it hasn't.


    I have no gauges at all. I let the engine warm up now before I drive out of the driveway, other than that... I drive it like I just stole it. Same way I drove it without it being boosted, it just gets there faster now.

    Alpha Supercharger is still spinning fine... it gets rode hard, every time.

    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

    Joey | 2016.5 Base Black :BLACKSS:
    "Defensor Vindex" | "Born of Freedom" | "None Shall Pass" | "Deter. Defend. Respond." | "Supra Et Ultra" | "Valor Honor" | "Si Ego Certiorem Faciam... Mihi Tu Delendus Eris"


    "Dating a skinny chick is fun until you hit 110mph in the Slingshot and she flies out like a napkin... thumbsup.png" - 2W2X1

    Quote from 2W2X1

    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,

    Dave

    A solid answer in less than 10mins. BAZINGA.


    That helps put my mind at ease. I am at the 300HP mark and this helps put my mind at ease. I'll check out the setup you did for wokka and re-game my plans.


    I love you Dave@DDMWorks ... NO HOMO!

    Joey | 2016.5 Base Black :BLACKSS:
    "Defensor Vindex" | "Born of Freedom" | "None Shall Pass" | "Deter. Defend. Respond." | "Supra Et Ultra" | "Valor Honor" | "Si Ego Certiorem Faciam... Mihi Tu Delendus Eris"


    "Dating a skinny chick is fun until you hit 110mph in the Slingshot and she flies out like a napkin... thumbsup.png" - 2W2X1

    Quote from 2W2X1

    A solid answer in less than 10mins. BAZINGA.


    That helps put my mind at ease. I am at the 300HP mark and this helps put my mind at ease. I'll check out the setup you did for wokka and re-game my plans.


    I love you Dave@DDMWorks ... NO HOMO!

    I think you need more HP!


    And yes Dave is the man!

    You know the man behind the curtain our own Wizard of o2

    The more people I meet

    The more I love my Dog!