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I wanna de-stroke a 3.8

Discussion in 'V6 Development And Modification' started by Dr Goggles, May 25, 2010.

  1. delcowizzid

    delcowizzid on holiday

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    probably have it in pdf :dD my mate cut the spine off and scanned it
     
  2. ozman599

    ozman599 New Member

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    Hmm, yyyyeeeessss.
    But you state yourself "otherwise the drag will swat it" so less drag will get you there quicker for any given power. Then you just have to get it to rev higher.
    Cheers, Steven
     
  3. immortality

    immortality Home of the smoky breakfast Bacon! Staff Member

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    yes please :D

    i think what our friend is trying to say politely is that at this point they are in need of more power. when they have enough power to "over power" the track because of drag then using fairings will be the next step

    I wouldn't worry about the engine failure to much. we have a number of good reasons for it and we can ensure that those don't happen again (or at least we are trying to do everything we can to eliminate as many as possible :) if the engine hadn't of lunched itself i'd imagine that it was good for a bit more yet.
    Gliders are a very good example of high efficiency aero designs...... bloody good fun too when it's just you the wind and the clouds :D
     
  4. soop

    soop Banned

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    If it had 330k on the clock, it did pretty well I reckon!
    There's nothing inherently wrong with the buick motor, I just think the nay sayers don't like the sound it makes. (Not enough cylinders for them)
     
  5. Dr Goggles

    Dr Goggles New Member

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    I'm not into drag........................

    EXACTLY , gliders are built to get the maximum amount of flying done, high lift low drag, for us we constantly get people quoting Goro Tamai's book "The Leading Edge" about aerodynamics. His expertise is in solar powered cars, low speed super high efficiency aero design. Much of that stuff doesn't have an application for us, but as I said earlier the laws of physics are immutable.

    I had a big reply written out over breakfast and when I went to "advanced" my biscuit had gone stale and it dropped the lot...... the guts of it was that the axles are at least third in line behind the wheels and the wishbones , the sensible fix would be a panel that covered the entire area between the axles out to the inner edge of the wheels,doing this however would double the wetted area of the car, which has it's own drag issues.....

    Bart has put it simply there, once we've got enough power to light it up , and then start getting speeds where the revs indicate we are getting consistent wheel slip a review of the bodywork would be time well spent , but in a broad sense we haven't found the limit of the body yet.

    330,000k VP Berlina one owner. I'm keeping the block because it's never been bored and I was the first person to thrash it. It was a wierd feeling as it was hitting the limiter it was like hitting deep water on the road....bang, bang, bang making my eyes bug out of my head with the decelleration....I'd be interested to know what the top speed of a stock VP was at 5200rpm if they got there.

    Force due to drag is a curve proportional to speed, the rate that the car accellerates is the power that the car can put down to the track at a given engine speed minus the total drag at that speed. At some point that gap closes to zero.

    Now.

    If the wheels spin, you are hitting "aero wall" at this point you can use downforce , or better ballast because although it slows the rate of accelleration it doesn't add to the drag.It allows high powered cars to hook up.

    If the revs just refuse to rise then you don't have enough power.

    We don't have wheelspin and the car with the limiter off kept accellerating til it suddenly went away,it didn't plateau , it hit 195mph then dropped off slightly quicker than it had been accellerating...that was the motor beginning to seize, the oil pressure failing and letting the lifters down....or whatever it was.

    Had we covered the axles , wishbones and radius rods that still wouldn't have been 200mph because we weren't experiencing wheel slip, the motor just didn't want to go for three miles at 6500rpm.

    That's what we need to fix.
     
  6. westerlybreeze

    westerlybreeze Member

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    Delco rev limiter

    Delco softened the rev limiter in the tune I had him do in my turbo wagon. By raising the limit and raising the point that it brought ignition back online = less of a harsh effect :thumbsup:

    Great read btw ;)

    Ps couldn't a 1 bar tune handle a few psi above atmospheric? :hmmm:
     
  7. Dr Goggles

    Dr Goggles New Member

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    Stock cubes

    That was a dead stock motor with a port clean up, dual TB's and a big exhaust....we thought we had the limiter fooled, but we was the fools.

    Last year it had no limiter apart from the brains behind the build.

    The very first time I drove it at Managalore airport I was running out of runway( and heading for a strip that light planes were using) and the two rear drums weren't pulling it up quick enough even with both feet on the brake pedal so I flicked the main switch off to try and engine brake her a bit more, I must have pulled a u-turn at about 80k's, I thought it'd slide...but no it stuck like an F1, just before I had her straight I flicked the power switch again, in all the excitement I had my foot on the throttle and off the clutch, let's just say it fired straight away and I had it a bit sideways, I'm not too proud to say it scared the **** out of me....I was still thinking I was about to drive into the path of a landing plane, the cab was flooded with fuel fumes, it was as noisy as hell, the shift we had then was very difficult to use,no suspension and the strip was REALLY harsh so I'd been airborne a few times and we had NO padding in the seat at that point.

    It was an auspicious start.
     
    Last edited: Jan 7, 2011
  8. soop

    soop Banned

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    Takes a brave man to drive a car HE built. Espcially one like that!

    Can I have a go? :D

    How are the regs on head work and such?
    Is to worth going with really big valves and nice big ports to get lots of air and go juice into the cylinder?
     
  9. CHEETR

    CHEETR New Member

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    salts hey?

    my uncle is glen davis, birth of a challenge twin v12 rolls royce merlin motors supercharged on the meth , quite well known out in South Australia!! i love it out there

    he was attempting the 500mph LAND speed record for 10years or so until the lake flooded and wrecked the car about 10 years ago now
     
  10. Dr Goggles

    Dr Goggles New Member

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    Yeah, I know the car , the guy who bought it is building it up with two gas turbines from what I recall...he's not short of a quid..... I'll try and track him down on landracing.com...

    here

    glen davis

    No regs at all Soop, we're just doing what we can afford and organize......

    As for driving, it's only had eight full runs, I dunno but I might get bored with it......just kidding but you'd be surprised how uneventful it is when everything is going smoothly...
     
  11. soop

    soop Banned

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    Well I still got a set of those heads you gave me here.

    If you want, I can rebuild them. Give them a good hogging out (Don't expect an idle) and send them your way?

    What sort of valve size is going to work the best?
     
  12. Dr Goggles

    Dr Goggles New Member

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    Heads up

    They're for you, but if you want to experiment we make good guinea pigs , however....

    I bought a pair of heads that were supposedly done by Trick and Mansweto, they look like they have Ecotec valves in 'em..Steve from MACE seemed suitably impressed with them, they were built for a turbo motor, however I have it from good authority that the particular needs we have mean that turbo heads are fine, as we are there for the top end.

    If they are genuine T&M they were cheap , if they aren't,they weren't.

    They look pretty good and we have the stainless roller rockers that Steve modified for them, we just have to decide on how we are going to cap the lifters.

    On another note I bought a 351/C6/9inch F100 Ambo yesterday as a tow vehicle...... I crossed to the dark side....:hmmm:
     
  13. soop

    soop Banned

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    Yeah fair enough.
    Whack some pics up of the fancy heads mate.
     
  14. Dr Goggles

    Dr Goggles New Member

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    Heads up

    Now, we mix some of our favorite hydrocarbon with some of that lovely Lake Gairdner air........
    and we poke it in

    here.........
    [​IMG]

    it comes out the big valve ....here
    [​IMG]
    and it goes BANG.....then it goes out the little valve...and out through here...

    [​IMG]
    then these things go up and down a bit more
    [​IMG]
    and it all happens over again, and again, and.....


    Obviously the yella Terra rockers are going, Scotty of V6 Vengeance saw them and said "piss them off, I kept poking push-rods through them, you guys will wreck ém for sure"... so we got the stainless steel ones mentioned earlier.....
     
  15. soop

    soop Banned

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    Jesus, there's a fair whack taken out of them bastards.
     
  16. delcowizzid

    delcowizzid on holiday

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    looks like they have been decompressed and clearanced round the valves in the combustion chamber compared to a stock vr head so might lower comp a fair bit
     
  17. Dr Goggles

    Dr Goggles New Member

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    yep.

    That's where my experience and those who really know their stuff in landspeed go their separate ways, an early mentor who I have mentioned before , Jack Dolan from San Diego ran lots of Buicks in various capacities and was a big fan of th de-stroking job. He , counter to much current thinking didn't get carried away with compression, he liked short stroke moderate comp motors as he reckoned they performed well at the top of their rev range, I can't defend this standpoint with what I know but I trust his judgement based on his record.

    If things go as planned and we get this build properly dynoed we will then have proper shift points to follow, hell, we might even use first gear.......if what I suspect going on the cam and those heads this will be a pig low down and so we won't be able to chug away in 2nd gear.............
     
  18. soop

    soop Banned

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    Looking at that cam, down low will be about 4000rpm....
     
  19. Dr Goggles

    Dr Goggles New Member

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    Grunt work

    Ok. Got started properly on the car itself on the weekend. There were a couple of spots we cleaned up and repainted.The salt is really hard on things , and it doesn't just sit there dry, it attracts water.....so as long as there's some SOMEWHERE the rust continues unabated..... Maybe next year we'll get the frame sandblasted and spray it again but the last three years we've just brushed it, heaps of cold zinc and then a slop over the top with safety yellow tractor paint. No, don't tell me ..." mate, you should get it powder-coated, or do it in 2pack".....powder coating isn't worth sheet , the moment it's chipped it's game over rust starts everywhere under it, as for two pack it'd be good but not really that much better at preventing rust than what we're already doing and when it comes time for a repaint it's harder to get off......so yeah, it gets a paint job like a five year olds finger painting.

    I started putting the fuel system back together . We have a 10 litre tank, a high volume steel canister filter and then a Bosch 910 . The tank is full of foam and there is a baffle where the return line enters to stop agitation. We cooked our last pump from what we think was cavitation, that was why the foam went in. Last year just gone the remains of the motor showed signs of a high rev lean out ....when I went to put the line from the tank to the filter on I noticed that it looked as though it had been sucked flat where it took a 90 degree bend from the tank.... I replaced that with a curved right angle bend of steel. Underneath the fuel tank sits a piece of 6mm gal-steel channel which covers the tail shaft...and prevents an ugly outcome if the tailshaft( which is only 100mm from uni to uni ) lets go... I bulked up the way the channel is secured just for piece of mind.....

    Up the front I was never happy with the way we had set up the steering column , I ditched it from the two knuckles back and got a fresh one( early Laser) , put another support bearing in and made another hanger for it, now it's possible to mount the tach lower, the whole arrangement is tidier AND it's stronger with less play.The problem with the way the tach was mounted is that it was difficult to find a spot where you could see over it, and not be touching the helmet against the roll bar padding, when that happens your eyes "grey-out" from the vibration and you can't see anything , not blurry, just grey nothing, it's pretty scary the first time it happens. I used to drive the car looking at the track markers about 20 degrees off centre......

    Because the car will be going over 200 this year we needed to fit 1 inch wheel nuts. Same size stud but just 1 inch hex instead of 13/16......now you can buy buckets of wheel nuts for SFA, standard ones. The inch jobbies cost me the measly sum of $6 a pop , that hurt buying 22. I can only figure that they have seen wheels pulled over the wheel nuts in crashes to mandate the bigger ones.

    Helmets are certified by Snell and need to be within ten years of their cert date , ours is a SA2000 bought in 2006 , so we need another one of them even though ours is immaculate, never dropped or scratched and only worn about fifteen times in anger.

    More soon.2roo.
     
  20. 89vn_Jai

    89vn_Jai New Member

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    Impressive story. I really do admire how much stress these engines need to handle.
     

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