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De-stroked 1600

Discussion in 'Performance' started by gusfallis, May 16, 2012.

  1. gusfallis

    gusfallis Member

    Messages:
    112
    Location:
    Newcastle
    Been chasing info on my engine for ages now with not much luck.
    It is a de-stroked 1600, the CC's come in at about 1597 when you do the maths on the stroke and bore.
    It has a 62 stroke, yes a 62 stroke, I have pulled it apart to measure myself, with 90.5 pistons. The case has been machined back and the pots machined off as well. this makes the engine 7mm narrower than a standard 1600.
    Valves are, exhaust 35, inlet 40.
    1:34 ratio rockers with dual berg springs.
    Camm is a K8.
    It came with twin 44IDF's that are rich down low but lean out at about 6500rpm.
    I've tried various jet set ups but because of the short stroke and the large diameter it is hard to get a good set up across the range and following weber tuning info it seems to do the reverse of the normal principle.
    Does anyone out there have any knowledge of this type of engine. I have been told they where used for speedway racing years ago.
    It is a pig to drive down low due to the cam but I have learnt where the power is to cruise around and it is great fun to drive, especially when the revs get up a bit.
    Any info on known carbie or injection setups to run on these would be greatly appreciated.
    Thanks, Gus
     
  2. vassy69SC

    vassy69SC Active Member

    Messages:
    995
    Location:
    Brisbane
    Hey Gus

    That will be a little screamer.
    Give me some info on your carb setup currently:
    - venturis, idles jets, main jets, air correction jets, emulsion tubes.
    No reason we can't get it to run fairly nicely with time and effort.
    The cam is big on the duration for a kombi with that size motor after having a look at its specs. That will be the difficult part.
     
    Last edited: May 16, 2012
  3. gusfallis

    gusfallis Member

    Messages:
    112
    Location:
    Newcastle
    Air correction 190
    Emulsion tube F9
    Main 145
    Idle 55
    Venturi 36

    I have gone up 2 sizes in both directions with the main. 145 covers the best range, bit of a stall on change over around 2300 but supplies well up to 6k to 6500rpm. bigger main to hard to drive with the cam duration down low. Smaller main dies of around 5500rpm and very sluggish to get there compared to 145.
    Gone up and down 2 sizes with the idle jets with 55 being the best all over at idle and up to around 2k.
    Spent a few dollars on jets so I'm at the stage of gathering more info on things like Venturi and emulsion tube before I invest more money on components as with a dual setup I need 4 of each size.
    My experience is saying smaller venturis and then jet to suit. I know this will change the upper limit range of the engine. Can't get enough info on emulsions tubes to work out the overlaps and cut ins of the various jets at differing rpm.
    The carbs balance well, run well, drink a fair bit around town but are quite good on steady speed driving.
    I ain't ghot alot of torque down low but when you hit 2500rpm and it keeps accelarating to 90kph at 6500 in second gear it brings a big smile to your face, and a surprised look on others around you.
    I've driven pig engines before and you get used to each one individually and learn how to drive them.
    This may be the best setup for this engine, if so I'm happy with it. If not then it's only an improvment and maybe a bigger smile on my face.
    Any help on setup is greatly appreciated, Gus.
     
  4. vassy69SC

    vassy69SC Active Member

    Messages:
    995
    Location:
    Brisbane
    You have certainly given it a go which is good to see.
    It will be challenging. I certainly agree that smaller venturis will improve the low end response. The 36 venturis are aiming at nearly 7000rpm peak power (approx) for that size engine. A 32mm venturi will bring that back to just over 5500rpm peak power. That is what I would be aiming for. See pic below of venturi selection and peak power.

    [​IMG]

    I am surprised with the 55 idles. I would have thought 60's.
    The mains should come back to 135 with the smaller venturis.
    It will help to do a little dyno time with someone who knows VW's and webers or alternatively someone who has an Innovate Motorsport LM2 or similar to log air fuel ratios. Aim for low to mid 13's in air/fuel.
    One thing the air correction does apart from make the engine go leaner in the high end is bring the main jets on sooner. Remember that if you are changing them.
    Below is a chart of emulsion tubes. I don't think the f9 will be too far off, though the f11 is a popular one for VW's.

    [​IMG]

    Keep us in touch as you work through it.
    Marcus
     
    Last edited: May 17, 2012
  5. gusfallis

    gusfallis Member

    Messages:
    112
    Location:
    Newcastle
    Hi Marcus, thanks for your info. I have allready got that hand drawing of the emulsion tubes along with a few other hand drawn ones. Can't seem to find any printed data on them with gauranteed data but. The F9 seems to work well but I've never seen any other info on a VW running them, as you said mostly F11's.
    My only worry with the 32 venturis is that they will run a little better in the mid region and my current top end will disappear and there won't be much change to the sub 2500 area due to the Cam duration.
    Currently I have pretty good mid range that goes into the top end very well with a bog down in the sub 2000rpm range.
    For the price of 4 venturis do you think the low RPM will be improved or will it still be a bad low rev engine.
    I don't mind the boggy low end as I have gotten used to driving it now and know my rev power areas through the gears.
    If I know I will get more torque in the low revs with 32 venturis then I'd consider the purchase.
    Hope this makes sense.
    Any experience or knowledge on this decision would be great.
    Anyone else out there had any experience with unusual setups. Info from anywhere may help out.
    I'll keep trying Marcus and I'll keep you informed of my changes and what improvements, or dissapointments I get.
    Thanks, Gus.
     
  6. vassy69SC

    vassy69SC Active Member

    Messages:
    995
    Location:
    Brisbane
    What spares do you have?
    airs, mains, idles, emulsions, venturis?
    You will have to get some more options I expect particularly on airs and emulsions.
    I'll come back with a little more info over the weekend.
     
  7. vassy69SC

    vassy69SC Active Member

    Messages:
    995
    Location:
    Brisbane
    Hey Gus
    You will need to do some dyno time or get an A/F ratio machine up the exhaust to get it really right.
    The direction to head I believe is the following:
    leave the vents as they are 36.
    Idles need to go up in size 60's
    Air needs to come down (180's or even 175's)
    The mains leave alone for the minute but may go either way.
    Dyno time or A/F is mandatory. I did a run in my ute with the 45 dells on it this afternoon (1st chance to A/F it since putting them on just over a week ago) and I have to change both idles and mains. Without that I would be guessing (really guessing). The Innovate Motorsport LM2 is a good tool, not too pricey and easy to use.
     
  8. gusfallis

    gusfallis Member

    Messages:
    112
    Location:
    Newcastle
    Hey Marcus, I have just ordered the 60 idle and 180 air correction.
    Should get them next week and fit them next weekend.
    Had a look at the LM2, looks like a good unit. Also going to look up an autometer fuel/air mix wideband set up as I have autometer gauges allready so may just look at a permanent gauge at the front.
    Hopefully your info will help out and I will cruise a bit smoother but still have the power there.
    Thanks again for your help, Gus.
    I'll keep you informed.
     
  9. vassy69SC

    vassy69SC Active Member

    Messages:
    995
    Location:
    Brisbane
    Come on Gus :)

    2 weeks. What is it up to?
    I have been working hard on my dellortos and now have them running beautifully ... mmm yum!
     
  10. gusfallis

    gusfallis Member

    Messages:
    112
    Location:
    Newcastle
    Hi Marcus, been a bit tied down.
    Got the 60 idles and 180 air corrections last Thursday.
    Didn't want to change them before I went to the nationals as it may have run bad. That would of been painful on the freeway to Sydney.
    Missus is away this weekend and the weather is crap so I might not get a chance to play around on Krackerz. I'll see if the kids are keen to help me out tomorrow, for 5 year olds they love helping out on the kombi.
    If the weather clears up I'll be able to do some drive testing.
    Might even fit the hotter plug and new leads I got the other week as well.
    Krackerz ran great on the freeway. Still dies a bit when the revs are less than 2500 when going up a hill. Hopefully the jetting changes will help with this.
    I'll let you know on my progress, when I get the chance to progress.
     
  11. vassy69SC

    vassy69SC Active Member

    Messages:
    995
    Location:
    Brisbane
    Cool

    Keep on to it
    It took 2 weeks for me to get the dells spot on
     
  12. damo99

    damo99 New Member

    Messages:
    22
    Location:
    melbourne
    why don't you try megasquirt injection .with a set of gsxr(suzuki 750)throttle bodys (very close to idf pattern,only mm's diffrence)
    you will have complete controll of your fuel map all rev range ,megasquirt is very easy to set up and you can either make your computor (about $180)
    or buy one completly built (http://www.diyautotune.com) (about $400) lots of info on shoptalk forums or the MSefi forum
    i am in the process of going dual gsxr throttle bodys (on idf manifolds)with the ford edis ignition system(no more dissy)
    so far cost has been under $600 and i've nearly finnished
     
    Last edited: Jun 8, 2012
  13. gusfallis

    gusfallis Member

    Messages:
    112
    Location:
    Newcastle
    Hey Marcus, I've got a carton of beer here to share with you. You where spot on with the jet selections.
    Changed them over yesterday and they idled really well. Went for a drive a discovered I had a new car.
    Didn't have to ride the clutch to get the right rev range. I could press the foot down at low revs without stalling the engine.
    I need to play around with the fine tuning of the mixture screws, linkages and timing but that will only improve it more.
    It smells as if she's running rich and blows a little smoke, white, when revved under no load, need to organise someone to follow me when under load.
    I haven't gone over 6k now but it's a smooth run all the way through the range so far.
    I don't have to sit at high revs in various speed zones just to have a smooth engine. I can putt around at lower revs and then change down when required.
    Been for a few drives now and I'm more than happy with how it's now going. I still need to pull the engine to change my front seal and fit the oil breather setup I've got to stop the covers leaking.
    Only thing, probably just not used to it, and may go away with some more playing, but there seems to be a tappity, poppity noise when accelerating under load. sounds a bit like an exhaust leak but only faint. I've checked all the exhaust and there's no leak. You hear it when driving next to a wall or confined area. People have told me it sounds good and no funny noises over the last 2 days. As I said it might just be me or it may go away with some fine adjustment.
    Thanks again Marcus for your advice. I might need your knowledge again for my next project. Going to build a high revving 1500 to put my Judson onto. Doing my research on the internals but will need to run them by someone who probably has more knowledge than me on engine setup. But that's another post in the future.
     
  14. vassy69SC

    vassy69SC Active Member

    Messages:
    995
    Location:
    Brisbane
    Glad to hear it is coming along ... I am really pleased!!

    I just changed the idles in mine to 68 and the mains to 160.
    It is feeling really good. I just need to fid out why the accelerator pump on the RHS carb is not responding as well as the LHS.
    Try the 150 mains again if you feel like it. It might work better with the bigger idles. Is the noise you describe when you are at 1/4 to 1/3 throttle?
    Mine does the same thing and on the AF it is leaner here than elsewhere. I will let you know when I find out more.
    Once again, I am really pleased to here the engine is coming to a more driveable place. The balance of the idle and linkage improves it again also.
    Cheers
    Marcus
     

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