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Thread: How to make our Scorpion race car faster!

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    How to make our Scorpion race car faster!

    Hi all, first time poster here, and member of Zanzabar88's 24 Hours of Lemons race team, running the '77 Scorpion. He's going to post a race recap with pictures shortly, but we wanted to start thinking about our next race.

    The biggest issue we had this time round, once we got past tech and solved some niggling issues was performance. We were suffering significant levels of fuel starvation on long , fast right-hand corners, and overall the car was just too slow.

    It's clear we need to upgrade the carburetor, but this being 24 Hours of Lemons we can't go out and drop $600 on a brand new DCOE 40. What suggestions would you have for the best combination of value and performance for the biggest performance improvement?

    We've got a line on a used DATR 34, which I think aligns with what is used on the Montecarlo. Are there any other options which we could find used that would be an improvement? Do we need to be concerned with fitment e.g. are Webers make/model-specific? What size would be best - is there anything that is too big?

    Thanks in advance!

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    Re: How to make our Scorpion race car faster!

    Maybe use a bank of carbs from say a 600cc motorcycle? Seems like they've been used to some success on Fiats and easy to pick up a used set for cheap. Gives you ITB's but you may have to do a custom mounting...

    Jay was also inquiring about my Scorpion trans and I have a spare flywheel that you guys could have to machine down to a lighter weight for quicker throttle response...

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    Re: How to make our Scorpion race car faster!

    More compression. The US spec 1.8 motor is in the very low 8s, and a bump in compression for $189 & a couple weekend's work is worth a look. Of course it's said that "all the power is in the head", meaning some machine work up top is also a good idea.



    http://www.vickauto.com/newstore/ind...oducts_id=2998


    I love that y'all're racing Lemons with one of these, best wishes!

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    Re: How to make our Scorpion race car faster!

    Quote Originally Posted by Chad C. View Post
    More compression. The US spec 1.8 motor is in the very low 8s, and a bump in compression for $189 & a couple weekend's work is worth a look. Of course it's said that "all the power is in the head", meaning some machine work up top is also a good idea.
    What would you suggest is the proper order if you were to have the following options on a limited budget. This is my theory:

    a) upgrade carburetor (e.g. moderate upgrade 34 DAT)

    b) high compression pistons

    c) exhaust header such as the ANSA 4-1

    d) moderate upgrade in cams, such as the 40/80s

    e) dual carbs and intake manifold such as IDF or DCNF (not really realistic for our situation, too much $$$...but maybe someday)

    f) racing cams such as the Alquati 42/82?

    g) fuel injection
    Last edited by zanzabar88; 6th October 2017 at 05:52 PM.

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    Re: How to make our Scorpion race car faster!

    I also want to make sure we have this engine running fully tuned up whether we add a new carb or any other parts. While we were racing I did just enough to get it running and set timing to ~10deg advance (measured at flywheel marks) thinking that would help it perform at high revs, but admittedly my knowledge is very limited on how to tune a carbureted engine! The idle speed and mixture were likely not ideal either. It seemed to rev well and run fine, but there was a ton of popping and light backfire on deceleration. No loud big bangs from the backfire, just popping. The exhaust we have on their is extremely short and just a cherrybomb glasspack so that might have something to do with it. The welds on the exhaust are pretty rough, so potentially a slight leak in the system as well.

    I think for the next race we will want to upgrade just the carburetor and dial in the timing. The 34 DAT seems like the best budget option here. Any help in choosing jets and etc. is very much appreciated!

    I'd like to add an air/fuel gauge too so we can perhaps avoid running too lean and damaging the valves. I have a Fiat 124 lambda sensor, anyone know what gauge I could plug that into to show A/F mixture?
    Last edited by zanzabar88; 12th October 2017 at 03:30 PM.

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    Re: How to make our Scorpion race car faster!

    With the LeMons budget in mind, can you just skim the head to bump up the compression? I know you can put a 1.8L head on a 2.0 block for higher compression, and have been told you can put a certain 1.6L head on the 1.8 block to do the same thing, so wondering if skimming the 1.8 head can have the same effect. I've bought two used 34 DATRs for under $100 in recent years; I can't imagine that market has changed much.

    But if the 1.8 is lacking anything, it's torque. Are you allowed to swap engines? If so, see if you can pick up a 2.0 out of a FIAT or Beta for cheap, and put the 1.8 head on . . .


    Best of luck in your efforts, and yes, please post pics!

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    Re: How to make our Scorpion race car faster!

    Yeah, that seems like a decent option. Any idea how much to skim and what the change in CR would be? Might be worth doing at the same time as a valve job and install 40/80 cams. On the other hand, the high compression pistons are not particularly expensive and that might actually be easier. I think I'd prefer doing the pistons at the same time as rebuilding the block with new bearings and honing the cylinders, etc. at a machine shop.

    Anyway, all of this is hopefully at least a couple races away (maybe before the fall/winter 2018 races)...assuming the engine keeps running for the next two races (December and March 2018 ).

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    Re: How to make our Scorpion race car faster!

    Port the head. This will give you the biggest increase in power as you rev. It has the benefit for your series, in that it can be free horsepower. If you do it yourself, which is quite possible, it could cost you nothing. Well, except replacing the gasket that is.
    You also need to get your fuel and ignition system sorted. It should not pop, etc. May need to clean out the carb, or check jetting, float level, etc. Also very easy and free on the weber.
    Then you can look at pistons, maybe a performance intake cam, some race tuning. Alternate to pistons, sometimes complete 2L block can be found cheap, will give more torque but a little less top end.
    Lightening flywheel is another option for a cheap mod that can help. Also shed weight throughout the car. If there's things you don't need, can you sell them and use the profit towards things like pistons, carb or lightened flywheel? Cutting one coil off the front springs is free. I think struts on these may be rebuildable with motorcycle fork oil. Another cheap mod to improve handling.
    Do the free things and easiest things first and things were you don't have to open up the engine, then just progress from there.
    Good luck, let us know how you do, and keep the shiny side up.

    Dave

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