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hoffman900

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Everything posted by hoffman900

  1. No that just sounds like bad shock tuning.
  2. Peter Wright also with the explanation:
  3. They had a different set up. It’s documented everywhere. Adrian Newey absolutely needs a wind tunnel and cfd. Also, I always think it’s a bit disingenuous he gets all the credit when he is dealing with nearly 1000 engineers across RB and their suppliers.
  4. Thanks for the image! A lot of people give Adrian Newey credit on RB’s side right now, but he was only 23yo when they got rid of tunnels in F1 and he was in Indy Car until 1985. Tunnels were used there but the tools were really rudimentary. I think from the chassis side of things, RB’s technical partnership Multimatic helps a lot, especially with their CART/Indy and WEC/IMSA experience. Obviously, it still stems from an aero issue. I found a post from a former F1 aerodynamicist some years ago talking about Karman Vortex induced oscillations in regards to the front
  5. That was a long time ago now (a decade ago). I think George is willing to go with whatever the engineers give him at this point where Lewis, as he has gotten older, is more of an Alain Prost type, and seems to have a lot more input into the setup. It did work better on hard tires later in the race, with Lewis running the same times as George on 20-some lap old hards to George’s fresh mediums. The problem is they are setting up around this porpoising issue, so a lot of what they are learning now won’t hold true when/if they get the car working.
  6. Correlation issues. There has been much talk about what causes porpoising. The F1 media talking heads attribute it to the air stalling, by a PhD Aerodynamicist I am friends with said on day 1 at Barcelona is that is caused by vortex shedding (Karman Vortex street) inducing resonance into the chassis and aligning with the frequency of the suspension to cause it. Jean-Claude Migeot was the only talking head to comment on this, and James Allison later said as much when he said the F1 media-sphere was incorrect. The problem is these things cannot be seen in CFD. CFD does not handle turb
  7. I don’t build engines and am busy with another project. It would likely be the same or more expensive. More expensive because you are stuck with stock rocker arms, so you’re going to have to go with proprietary lobe designs and cam core to get the lift you need, vs being able to likely use an off the shelf lobe design (say from an older NASCAR application). Everything else is all going to be custom anyway. Less compression isn’t always a bad thing. Anything with more than a flat top is a compromise in terms of combustion efficiency… does the increase compression offset comp
  8. Engine dynos are just as variable. Sweep rate alone on a water brake will change things. Chris, I doubt they do. It's not hard to figure out who's blustering. I think a lot of TR's end up around 180-185bhp. Most are also using the same tried and trued formula. Trap speeds usually show who has what.
  9. Driving sure helps, but it's also what your competition has. For example, the vintage B-Sedan classes here (1.8L Datsun 510, 2L Alfa GTV), the front is turning 2:36-2:38's at Road America. Chris, your IMSA TR8 with its previous owner, did a 2:39. A 120hp TR would be lapped by those cars... It's also not going to beat a 150bhp Sprit or a 140hp Spridget, weighing 600lbs less. 175lb-ft isn't a lot for the engine size. I know of 2L engines of similar vintage, but from other country origin, making more than that, and with 2 valves. There really is no secret. It's an airflow problem. You s
  10. 175lb ft of torque at 5700rpm is possible with the TR4 engine to the rear wheels, but that's a real race engine (and not a hand grenade), but it's still nothing out of this world BMEP wise. I usually figure 100hp / L is a good starting figure for a proper vintage race engine of any type (Spit, BMC A-Series, TR 4-6's, MGB's, etc.). Over that requires A LOT of work, but it's possible. The best A-Series here, are 108hp/L, and still pretty tractable, with SU's and stock valve sizes (rules required in SCCA Production competition). A great Spit engine is going to make 150bhp, or thereabouts.
  11. The torque saying should be revised: Producing the most torque at the highest amount of RPM wins races
  12. I've seen a 5 port A-Series with modern development and fuel injection make 165bhp... 126 hp/L. Efficiencies decrease with engine size, but I have no doubt with a proper modern development regime, over 260bhp is possible.
  13. Good stuff, John. +1 to what happened at the end?
  14. At the start? The grids are set side-by-side. Green flag is out, passing is allowed. Pole only gets inside track position for turn 1, we were qualified on pole (up to 8s/lap at one point) and pulled in early. The Lotus set a time a little faster on the last lap of the session. It didnt matter as we knew (and told him - very friendly guy) that the TR was going to go sailing by at the start. The Lotus played the start better on Sunday, but a fast in a straight line Datsun (~225bhp from a 2L 510 engine) ran up the inside and foiled his plans.
  15. Hah. Rules are rules. Do you still have your TR4?
  16. Hey Mick, .040 on the 86mm, so 87mm is what everyone runs. I think most anyone serious is offsetting the head to at least some degree. Standard stroke dimensions - all the serious racers are running ghost main billet cranks. Bearing sizes, etc. are all free.
  17. Hey guys, he's shifting at 6500 (except the starts), but the shift light was creeping down. Makes power and will spin up to 7000, but well only do that in anger (and power typically isnt the problem). Rules here in the States are based off old SCCA regs. So .040 overbore, no stroker cranks, no dry sumps, and no crank trigger ignition. Just about everything else is free and we can get 112 octane leaded race fuel here no problem, so compression ratios are higher than you see in Europe. 5spds are allowed in vehicles that came with overdrive stock, but has to be production based (interna
  18. Thought you guys might enjoy this... Saturday race: https://youtu.be/THsHEiI1LzU Drying conditions. TR4 fast lap: 1:36.560, Lotus fast lap: 1:35.632 Sunday race: https://youtu.be/-VgCi4kJJk0 Dry condtions. TR4 fast lap: 1:34:365 , Lotus fast lap: 1.34.175. Average speed ~86mph. Both turn their fastest lap on lap 4 (5:20 in) In-car from the Lotus.. Saturday: https://1drv.ms/v/s!AmUHWCpbUJmAq2zpqrxjostLd5Op Sunday: https://1drv.ms/v/s!AmUHWCpbUJmAq22d7LBxsgZDnoFw Enjoy!
  19. Longer connecting rods will reduce the mean piston speed, but just barely. One can play with the stroke/rod game, but when you figure out what can be used at maximum (in relation to where to put the piston pin), you'll find there isn't that much difference. The real gain comes in using a much lighter and stiffer piston. With the long strokes typical of the British lumps, anything you can to reduce rotating weight will mean longer life of the block itself. With the 4cyl TR engines, the block, for the very best engine builder, is becoming the Achilles heal and he's done everything to t
  20. Oil pump: Stock modified by Steve Yott, http://www.tonydrews.com/OilPump0001.pdf Piston clearance: Dependent on what type / manufacturer. A common forged piston will ever in the .003 - .0035 range. I can't comment on cast Pistons. Valve springs: Contingent on valve and retainer weight,how aggressive you are going to cam it and the rocker ratio, how much you're going to lift the valve. For the run of th mill street engine, get them from s source like here:http://www.aptfast.com/ShowItem/103426%20TRI%204%20Cylinder%20Double%20Valve%20Spring%20Set.aspx Pushrods: Trend,
  21. Likely different expansion rates. I do agree with the premise of filling the port as the TR ports are huge - at least at the inlet. Typically head porters will use epoxy like Splashzone or Devcon on aluminum heads. Sometimes you see them on iron drag race heads, especially in the NHRA Super Stock classes (stock head casting / port volume rule). Those guys will key the epoxy in with grooves cut into the port and the insertion of machine screws for it to grip on to. Even then however it requires to be ground out and reapplied after so often and methanol and other racing fuels will eat it if i
  22. I've seen those Ford lifters disentigrate like that too. Keep in mind those Ford lifters are a smaller diameter than a stock Triumph lifter. If you're mixing and matching parts, it's not a good thing... The best TR4 race engines are using stock diameter tool steel lifters on a custom billet steel cam core. That's almost a $1000 set-up. Obviously, you don't need that though How is your valve retainer to guide clearance? Not sure what spec valve springs Ken is selling. Did your cylinder head guy fill in the floor? Looks like he used lead? If it's lifting, then that needs
  23. What was the spring's seat pressure? Pressure over the nose? Tappet source / diameter ? Cam numbers? Even what the fastest racing TR4s run for springs, will not wipe a cam flat if broken in correctly and used with the proper parts.
  24. Dick is 82yo! The car is waaayyy faster than it was then. Rev range is up to 7k - it can go higher if necessary, but power is falling off up there.
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