Converting AWD Dsm to Open Light class
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Thread: Converting AWD Dsm to Open Light class

  1. #1

    Default Converting AWD Dsm to Open Light class

    I figured this is the best place to post this question. I am planning to buy a logged booked 1G Mitsubishi Eclipse. I want to convert the car to Open Light class, because I am a new driver. Has anyone done this by keeping the same engine and removing the turbo and blocking off the turbo lines? I guess this could also be a question for the Subaru cars converted to Open Light. Thanks

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  3. #2


    Assuming you're going for coefficients with plan to go back to turbo?
    Easiest is to remove turbo, fab a connector for downpipe to exhaust manifold, then just connect of block off oil or water lines. It'll be slow with the low compression.
    If you're aiming strictly for open light easiest to just find a NA engine that will swap in relatively easily.
    Grant Hughes - 1985 Merkur XR$TI Group 5
    885 Parfet St Ste C
    Denver, CO 80215

  4. #3


    I thought it might be that simple. I am planning on running the turbo once I get enough coefs. I am guessing the MAF should be able to adjust the air fuel ratio, because the air is going directly into the intake manifold? Any ideas on how power the engine will have with no turbo? The stock engine has about 200HP.

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  6. #4


    Quote Originally Posted by johbjork View Post
    Any ideas on how power the engine will have with no turbo?
    according to the internet, the 4G63 had 9:1 compression and made 135hp. The 4G63T had 7.8:1 compression - I'd guess 100hp, maybe?

  7. #5


    Thanks for pointing out that difference in compression ratios. My Chilton manual was showing the same compression ratio for the two engines, until I turned the page. It is definitely something to think about when the engine is only producing that little power.

  8. #6


    Ah but it'll make you learn how to drive a slow car faster.

    USUK Racing

  9. #7


    I did this in my STI a few years ago. I took the turbo motor and de-turboed it. However, because it would be so slow to the point of being hard to drive I bumped the compression from 8.2:1 all the way to 11:1. even this was very slow (136whp on a mustang dyno but with a very small area under the curve). I highly recommend you swap out your turbo motor for an n/a one. The drivability will be much better (I had a very narrow range of useful powerband due to turbo cams without the turbo)

  10. #8


    It might be a good idea to figure out where the compression differences are in the engine, is the big difference in the head or the pistons? If it is only the head, a n/a head would probably be easier than a whole motor switch. The Japanese do some interesting things in the name of assembly line ease.

  11. #9


    With a little more research I was able to find out the compression difference between turbo and NA engine is from the pistons. I think I will swap out engine to NA one and do a few other tweaks to gain some extra HP.

  12. #10
    One day I will finish this car
    Join Date
    Dec 2004
    cin, oh, usa.


    Or you could just find a donor N/A subframe. Keep it complete then roll out the turbo frame, roll under the N/A frame. Besides some wiring issue's that am sure can be delt with. This might seem like some work and the added space taking up by the extra subframe. But I think this is going be easier than swapping the motors out. This the idea for our Talon to try and run 100Acre Woods next year. Have to seam weld the engine bay and strut towers anyway. Just gonna roll the whole subframe out of the way at the garage one weekend.

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