this is just a subject out of interest.
I was watching some videos, firstly a f1 cosworth v8 doing 20,000 rpm,
followed by something a little more educational, some japanese show translated of the spoon engineers raising the red line of an inline 4 from like 7000rpm to 10000rpm. was a very eductional video, excuse the rice, but if ur a motor enthusiast, its worth the watch (translated) They proved its worth on the track with the same head geometry as the original engine in that it allowed a better shift rpm to maintain optimal rev position in the power band. (they race stock vs. high rpm)
Amongst perfect balancing and vibration reduction, as displayed in the last video, and taking into account conrod's and fasteners, valve behaviour, what over major keys are there to gain 'reliable' high rpm ranges to take advantage of high horsepowers from lumpy cams and head tuning?
From vague memory, i think i can recall some people mentioning 7000rpm red lines alone on their type 1 vw engines, (or course veyr much worked lol). I wonder what it would sound like at 9000rpm lol, If the headwork and cams proved to have any reason to go up to this rev range at all...
gene berg also talks a lot about this on his site.
he is so pedantic about crank selection, main to rod journal ratios, weighted pulleys, rod balance ect.
hes cranks are know to be one of the best because his wedge mate cranks are made with the fly wheel and dynamically balanced together with the pulley as well.
he only uses and sells stock vw cases as there is no need for a stronger one if the destructive vibration is eliminated.
71 notchback,
Past owner of, 70 NB, 73 SB and 72 FB TLE
I will post some pics of a 9000 rpm Holden V8 components tomorrow if anyone is interested. Yes thats 9000 rpm lol, It does go to 9500 but that gets a little costly lol. The old Holden V8 hey, who would have ever thought
I dynoed my old 2165 to 9500 although only 8700 was used in anger, and in the same era, late 90's, my type IV 2 liter bus engine was dynoed to 7500, both running Haltech EFI, and Berg valve train.
Matt Berry Motorsports...air cooled advice, repairs and mods Ph 0408 704 662
OFF-ROAD,CIRCUIT,DRAG,STREET,ENDURANCE
Craig Torrens6 times Australian, 7 times State Hillclimb Class Champion
matberry wrote:I dynoed my old 2165 to 9500 although only 8700 was used in anger, and in the same era, late 90's, my type IV 2 liter bus engine was dynoed to 7500, both running Haltech EFI, and Berg valve train.
wow....what power did the 2165 make at 9500rpm Matt ?
Here is the Inlet Manifold, Its a new design and its straight from the Foundry and machine shop, its not finished yet as the port runners have to be worked on yet, I start on them this week, grinding out and filling with Z Spar to get the most flow and fastest air speed but having the smallest port size.
I dug out the work book from the Joint Effort race car to check out how much power it did make, in response to Craigs question above.
I used the fuel maps as a upper rpm limit, and fuel was mapped to 9000, but realy only was making power to 7500, with a peak just over 135 rwhp between 6200 and 6900. At 8000 this fell to 110 rwhp.
This engine was built in 1994 and used a Gene Berg 78mm type IV centermain crank, 94mm p & c giving 2165cc.
My own heads were welded german 311 or so p#, 48 x 38, Chevy dual springs, and Haltech EFI with 51.5 ITB's
Matt Berry Motorsports...air cooled advice, repairs and mods Ph 0408 704 662
OFF-ROAD,CIRCUIT,DRAG,STREET,ENDURANCE
These are the heads, there sort of Aust Yella Terras, but they are blank castings with different position water jackets, then machined up with different port and valve locations and the ports sit 350 thou higher up than standard, Valves and Retainers are titanium, Inlet is 2.150 and exh is 1.67. Valves are 200 thou longer so I can run more lift. Springs are PSI and have 400 lbs on the seat and 1200 lbs at 786 thou lift. Its set up for 15:1 CR
Valves and Rods, rods are Lunati Pro Billet items with 215,000 arp screws, bushed ends and dowled caps, to help prevent the caps from walking, but they still walk at high rpm.
I dug out the work book from the Joint Effort race car to check out how much power it did make, in response to Craigs question above.
I used the fuel maps as a upper rpm limit, and fuel was mapped to 9000, but realy only was making power to 7500, with a peak just over 135 rwhp between 6200 and 6900. At 8000 this fell to 110 rwhp.
This engine was built in 1994 and used a Gene Berg 78mm type IV centermain crank, 94mm p & c giving 2165cc.
My own heads were welded german 311 or so p#, 48 x 38, Chevy dual springs, and Haltech EFI with 51.5 ITB's
Cheers Matt..big valves, did you need to go Titanium or just heaver springs ?...........yeah 1994 seems like only yesterday but geez it was 16 years ago, where does the time go ?!
I had the 1800 type4 in my bay up around 7000 rpm for a while. I was driving along some twisties in the morning preoccupied. Eventually it registered with me that the motor sounded a bit different. It seems I had gotten as far as 2nd and just forgotten to keep shifting.
Miracle it didn't grenade.
If at first you don't succeed. Build, build again.
Vehicle: 1975 Special order delivery walkthrough panel based LCA pop-top camper. Motor: Nippon 1.8L Single port Wasserboxer, Transmission: 3 rib 002.
If at first you don't succeed. Build, build again.
Vehicle: 1975 Special order delivery walkthrough panel based LCA pop-top camper. Motor: Nippon 1.8L Single port Wasserboxer, Transmission: 3 rib 002.
I had a buggy more road than off road. It was just a stock (well at least I thought) 1600 DP type 3 with dual carbs and 4 equal length straight out pipes.
I had to limit at 6k as it always reved out well past 7k. didn't realize it then but now that I think about it thats ridiculous 🤪
lol the tacho was a VDO 80mm and it could not keep up with the engine. ie it accelerated in revs quicker than the tacho could display.
Got one of those workshop tachos from work to confirm and yes the it was right? The engine I got was from a notch that I got from a scrap yard. The case had no engine numbers what so ever except the part number on the bottom and mexico made.
I am confused now?? what was in that engine?? I didn't know better then as I was only 17 when I built that buggy.
71 notchback,
Past owner of, 70 NB, 73 SB and 72 FB TLE
Chris,
There are several fundamental factors to consider:
1. Bore/stroke ratio. An oversquare engine (like the VW Type 1) where the bore is larger than the stroke reults in a lower maximum piston speed than an undersquare engine (for the same capacity and rpm, obviously). The Formula 1 engines are extremely oversquare in order to keep piston speeds down. Thus, in search of a high-RPM VW performance engine, you would want to increase bore without increasing stroke (and I won't even dare mention the numbers 1915 or 1916). Of course, this doesn't mean you'll get a more powerful engine than a stroker, just that it will deliver its peak torque in a higher rev range.
2. Friction. As RPM and piston speeds go up, friction losses (and heat generation) rise rapidly. Taking F1 engines again as an example, they're dry-sumped to keep the windage losses and foaming down. Great aattention is also given to piston and piston ring design to reduce friction, and exotic materials and coatings also make a contribution. So for a VW you would look at both dry-sumping and piston coating.
3. Valve closure. As RPMs rise, the problem of getting the valves and lifters to follow the cam contour becomes increasingly difficult. Notice clinker42's open valve spring force of 1200(!) lbs. Ducati addressed this by making their valve closures desmondronic (active closure rather than passive closure by springs), but the F1 engines use a different approach of pneumatic closure. This is an even greater problem for the VW (or Holden), because of the single inlet and single exhaust valves, which need to be enlarged to achieve high RPM but then become quite heavy, needing greater spring pressures, leading to greater valve train stresses and friction, more heat etc. For our hypothetical VW Type 1 revver, you'd want to find the lightest possible valves, pushrods and retainers that would do the job.
4. $$$. You'll be needing lots.
Of course, this is just me thinking on my feet; I'm sure some of the guys who actually build high-performance VW engines like Matt and others will chime in with some practical advice.
longer rods make for more rpm by increasing the dwell at the TDC thus increasing burn time which in turn throws the piston down harder.
This increases power at higher rpm and thus makes the engine able to rev higher. well as far as I understand.
Also I read and hear longer stoke engine make higher rpm. The logic behind it is that flame front moves at the same speed regardless of anything except fuel of course. Also piston speed is slower in long stroke/long rod engines at any given rpm VS short stroke .
Im confused now?!?! both make sense according to physics. the common thing I noticed in bother these claims is that all engine referred to were over-square.
71 notchback,
Past owner of, 70 NB, 73 SB and 72 FB TLE
thankyou all guys. Certainly some nice sounding combos for the perfect recipe Peter.
As with anything it sounds like it always comes down to dollar. I just have a keen interest in it.
a dub engine screaming at 10,000rpm? HOLY SMOKES! Vlad luv the berg quote of how an original case would do the trick if balancing perfect. I only eva had one going to 5500rpm lol, rev limited by the stock pict carby (1500).
I would imagine longer rods would suffer some serious strains in the process. Mr. Butler, aluminium rods i imagine they would be wrought aluminium? i spose by being lighter, you decrease weight and in turn reduce stresses in piston direction change, but then i spose trying to 'balance' it with enough strength to handle the rpm particularly when comparing strength to titanium. i have serious doubts the titanium is cheap lol. I hve heard of carbon fibre drive shafts, if they can sustain that kind of stresses as a 'performance' component, i wonder if there is a possibility of making a carbon fibre/titanium spined (to minimise flex) composite conrod.
I dropped my jaw when i heard about carbon fibre drive shafts... that stuff is brilliant. But i rekon it still has areas to be explored being light weight and strong.
Its coming close to time in my mech. engineering course at QUT to start looking at work experience to finish the degree, and it would be brilliant to get a chance to participate in spending someone elses money and learn/help upfront with other engineers by playing with some big guns. Getting some industry experience and a chance to put theory into practice.
longer rods suffer less stress because there is less side to side sweep. also this greatly reduces enormous stresses normally experience by side slap of the piston.
this stress is not eliminated but actually moved to the crank as increased torque. Its all about rod ratio.
actually we can just do away with the crank all together. its an old inefficient crap design.
vlad01 wrote:Also I read and hear longer stoke engine make higher rpm.
... the common thing I noticed in bother these claims is that all engine referred to were over-square.
But there's always an exception. The Honda Integra Type R, which is revilicious, is undersquare.
The longer rod concept has proven a bit of fairy stuff. My best mate builds nascar engines in the US and they have dont the 6.125 vs 6.00 vs 5.9 rod tests and and the TQ and HP difference is so small that he reckons you can no way attribute it to rod combinations. I should add that he isnt a back yarder, they have like 10 guys who work in the engine shop and they have 4 dyno rooms etc etc. So i do believe him.
I have been building $50,000 V8s now for over 10 years, most of the stuff you read, while it is accurate and factual, its absolute rubbish forthe vast majority of engines. Take valve springs for instance, we pay $3000 for 1 set and then have them cyro treated and coated and a few other things done. You can probably read about this sort of thing and think it is the ducks guts and is a must. But in reality these valve springs that are now worth $4000 are bugger all better than a $1,000 set. All they will do is allow us to run 7,500 rpm for 10 hours instead of 7500 rpm for 6 hrs. So does it really matter for us guys, nope.
clinker42 wrote:I have been building $50,000 V8s now for over 10 years ... allow us to run 7,500 rpm for 10 hours instead of 7500 rpm for 6 hrs.
Getting more and more curious on where you work clinker... or more correctly, which team it is you work for ??? I can only think of one situation that needs a $50,000 Holden V8 that does 7,500 rpm for 6 hours...
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It aint the red and white one Dave and they arent really Holden lol, they maybe in a Holden or should I say a body with a Holden badge on that has no more Holden in it that a Ford has Ford.
