2L 8V (2E tall block) engine into mk1 : which big bore tubular manifold is everybody using?

Discussion in '8-valve' started by Jon Olds, May 7, 2020.

  1. Jon Olds Forum Junkie

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    Just dropped the engine into my current (race/rally/not sure) project and the manifold Ive bought (4:2:1 generic stainless) is a tight fit. I am going to start modifying it to fit but wondered if there was a sliding joint one around, like the ABF one, suitable for short and long blocks.
    Its going onto a eurospec head, hence the need for large bore
    Help and comments always appreciated
    Jon
     
  2. mr hillclimber Club GTI Supporter and Sponsor

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    I do 3 different types Jon....4-1 & 4-2-1 for the short block and 4-2-1 for the tall block. They're special order only but I can check if the fabricator is in next week and get a lead time if that's a help....Email me.

    Failing that a 4-1 Ashley should fit as a budget option ...I've seen it done...but you may need to adjust the floor a bit for clearance.
     
  3. Jon Olds Forum Junkie

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    Thanks. I'm going to 'play' with the 4:2:1 one I have first as the lengths are good, the head mating flange diameters are nice and big and its clear of the floor by a reasonable amount. Its tight around the rack mainly, but I am going to try an engine tilt first, and remove a bit metal here there. Possibly wedge the manifold face if I can get it clamped into the mill.
    The outlet at the 1 end of the 4:2:1 is way to small, so this was going to chopped off anyway, so the manifold was sacrificial whatever happened.
    Not keen on ashleys, even though I have two that I have used and modified, over the years.
    Haven't decided on a cam for this yet, so whatever exhaust config I end up with will have some bearing. Thinking a 4:2:1 may be better than the default 4:1 I usually use. It will be on a mapped system with 45 bodies
    Jon
    If anybody has a 295 degree ish 11.5mm to 12mm mech cam spare, drop me a line, I'm in the market..
     
  4. mr hillclimber Club GTI Supporter and Sponsor

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    No problem at all.

    Depends on you definition of better Jon. The right 4-1 will out hp the 4-2-1 but can have the odd hole in the power curve...though with ITB's and management you maybe able to get around it subject to primary length and overlap.

    A 4-1 Ashley covers a broad range. I've used them on road engines up through to race units making almost 200hp on a 2tr...185 on 1800s. On carb engines they work great for the money.

    Latest developments have gained 5hp peak with better peak torque and more low end from getting the lengths and the collector right...that's direct back to back same engine, same dyno same day with an Ashley vs our 4-1.

    Also on the same test our long primary 4-2-1 gave a better spread than the Ashley and a bit more peak but couldn't match the top end of our 4-1. The 4-2-1 did beat the 4-1 by 10ibft @ 5000 though as the engine came into the power band.

    I've used a 296 profile to make a genuine 180hp from a 1900...good spread. If your looking to crack over 200hp+ you'll need 310-320 duration and 470+ lift and 12-13:1 C.R.
     
  5. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    The camshaft choice will impact the ramming effect of the inlet tract and the scavenging effect of the exhaust header, for a given static CR.

    So trying a 4-2-1, when there are plans to be more extreme on camshaft choice later on, makes the settings/hardware for the future engine redundant.
    The results you see now as also dependent on how well constructed the 4-2-1 is. How well this part is made is unknown as there is no reference for a "optimum"

    I should add also, a result is not how more bhp an engine achieves, but what maximum torque the engine can achieve for the engine operating envelope you are likely to drive it at.
    So experiments like these take time and through testing to determine what is best for maximum response of the engine at any load request.

    Jason pointed out a specific example which seems to point to a 4-2-1 system having more maximum torque (best cylinder fill) vs a 4-1 systems ability to encourage more cylinder fill at higher rpm. However that engine is not your spec.

    For your stuff, you will find out the optimum by experimentation and by potentially tweaking primary and secondary stuff yourself, with tweaks to the ECU calibration.
     
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  6. Jon Olds Forum Junkie

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    Longer term plan is to get my engine dyno up and running so I can do back-backs and calibrations without having to rely on expensive chassis dyno time. Its been sat in the shed waiting for my retirement for some time now....
    Nothing I ever build gets fully optimized, there's never been the time/money/opportunity available. Always learn plenty though, that's what keeps me tinkering.
    In the meantime I'm just enjoying the building process making use of the parts that come my way. The most interesting thing I'm likely to learn from this 'budget' build is how well the eurospec head port shapes and sizes work. Usefully I have a semi downdraft longman ex F2 head with the same combustion chamber volume that is ready to bolt on. Could be a very interesting comparison, if it happens. Also, may drop it back onto 45's for a back-back.
    This virus means the car wont be used in anger this year for sure, maybe not until mid next year, so plenty of play time to come.
    Inlet tract length is also something I want to play with as well, I have a couple of ideas of stuff I'd like to try, just for interest. (never easy on an 8v mk1..)
    Your input always appreciated
    Jon
     
  7. Jon Olds Forum Junkie

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    Ordered a quick rack from rally design (to quaife..) about six weeks ago, covid means I have no clue when it will arrive, if at all.
    Anybody got one left unused from the group buy? Be delighted to pay the rally design price for it
    Let me know please
    Jon
     
  8. mr hillclimber Club GTI Supporter and Sponsor

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    Ed very close...peak torque was actually a pinch higher a few rpm further up on the 4-1. The 4-2-1 gave more just below peak torque but not quite as much as the 4-1 further down. Though as a circuit race engine designed to give it's best from 5 to 8k power down at 3k shouldn't be a concern or be using full throttle anyway.

    Jon your 2ltr should have plenty of grunt even with the big valve/port head from fairly low down whatever cam you run from 290+ up...even easier to set up on injection.

    Very big overlap cams and carbs are hard to set up lower down at full throttle, though I find them fine at 3/4 throttle. On injection and management they'll take full throttle down at 2k, on carbs they won't at 3k on big overlap around 100-120 degrees.

    Your also likely to find the 45 carbs (Not the bodies) too small...I have recently north of 190hp. But if you operate within the power spread of the components you have it'll be pretty decent in performance terms.

    Good luck with playing with the dyno too...lucky bugger!
     
  9. Jon Olds Forum Junkie

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    Thanks
    May need another of your special 020 gear linkages. Ronseal advert applies, they do as they say on the tin..
    This is a budget build at the moment, so 7K will be redline, ish
    Not a clue what 3/4 throttle is? Never ever used it ? Must be for track days, or something.. LOL
    2K revs, that'll be for loading onto the trailer....
    Agree with choke sizing, from experience. My 2L engines seem to like 40's, not 38's..
    Any comments on newman phase 4 race? Numbers look good, and you supply them. Also, price seems fair
    Dyno cell system, bought it nearly 5 years ago, about time it was used, LOL
    Jon
     
  10. mr hillclimber Club GTI Supporter and Sponsor

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    No problem at all.

    We'll be making them in-house like the mounts soon-ish. I discovered I was being ripped off by the previous manufacture selling them out the back door at lower quality, so a bit later in the year we'll look at the linkage again to join the mounts, along with some improvements.

    The 2ltr 8v doesn't rev like the 1800's...even decent power ones peak low 7's rather than mid 7's to 8k for an 1800. But spec for spec the 2ltr does grunt more....146-150ibft for an 1800-1850, 160-166ibft for a 2ltr.

    3/4 throttle is for engines that are too much for the chassis!....or wild ones biased for top end that are road legal!

    No surprises there. A good 1800 gets capped by 45's with 39mm chokes, 48's with the same choke size show a decent improvement but are not an easy fit.

    That's their 296 and it's a very good all round base race cam. There's one in the reigning classic vw cup champs 1900 8v we did a few years ago for him, clearly still working ok. Peaks at 7k in 1800-1900's on 45's with 38mm chokes on a std bottom end with cast pistons and a 4-1 Ashley, 180hp and 148ibft isn't too bad. It should peak high 6's in a 2ltr so a natural 7k limit would work in its favour and make high 150's in terms of torque.

    Hope you live somewhere isolated as a dyno is a noisey ol thing to keep under the radar!
     
  11. Jon Olds Forum Junkie

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    You know the story, re noise and neighbours. That's why its been stored. Looking for local premises now, not easy. Second option is a mobile unit..
    Either way, I have the kit, and its decent stuff. It'll do 500hp at 10K, way more than I need. Compact also.
    Keep me up to speed re linkages, please
    Project coming along semi decent progress
    Not a show queen though, will load up some more photos for interest..
    Jon
     

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