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Brian_e
Samba Member
Joined: July 28, 2009
Posts: 3291
Location: Rapid City, SD
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 Posted: Thu Nov 02, 2017 9:03 am Post subject: Re: 2276/86b beetle daily |
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Torben,
Earlier you mentioned "Part of the trick of making good street engines is to chose and/or design the heads so they are in about 90% of their potential +/- a little. "
When you say 90%, are you using a calculated "required CFM" from pipemax or similar program (or real pen and paper math)? So the heads can produce an extra 10% more then the "required CFM"? Just trying clarify.
Thanks,
Brian |
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UK Luke 72
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Joined: September 07, 2011
Posts: 2867
Location: Little Britain
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jpaull
Samba Member
Joined: February 22, 2005
Posts: 3465
Location: Paradise, Ca
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| Posted: Tue Nov 07, 2017 6:25 pm Post subject: Re: 2276/86b beetle daily |
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Nice, are those the Mofo's?
_________________
[email protected] MPH 1/4 Mile & 8.1 @ 83.7MPH in 1/8 Mile with Mild Type 1 VW Mag Case 2234cc commuter engine in stock weight bug w/only .491 total lift(CB2292 Cam), 42x37 heads, 48idf's, Street tires, Belt on, Mufflers, Pump gas, video of the run here: https://youtu.be/M3SPqMOKAOg
Transmission by MCMScott:
Rhino case, Klinkenberg 4.12, Superdiff, 002 mainshaft with 091 first idler. Weddle 1.48 Third & 1.14 Fourth. |
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UK Luke 72
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Joined: September 07, 2011
Posts: 2867
Location: Little Britain
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UK Luke 72
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Joined: September 07, 2011
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Location: Little Britain
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Alstrup
Samba Member
Joined: July 12, 2007
Posts: 7216
Location: Videbaek Denmark
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| Posted: Wed Nov 08, 2017 8:14 am Post subject: Re: 2276/86b beetle daily |
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| Brian_e wrote: |
Torben,
Earlier you mentioned "Part of the trick of making good street engines is to chose and/or design the heads so they are in about 90% of their potential +/- a little. "
When you say 90%, are you using a calculated "required CFM" from pipemax or similar program (or real pen and paper math)? So the heads can produce an extra 10% more then the "required CFM"? Just trying clarify.
Thanks,
Brian |
Sorry for late reply. I´m a little busy.
Again, this is a personal point of view. Others may think I´m daft when I say this.
The 90% "rule" is looking at the desired engine performance in relation to the cylinderhead flow at the valve lift. If wé take the cnc wedge ports as an example we know that they flow about 207-208 cfm @ ,600" and 25" water (with a proper intake manifold) We also know that they have "high rpm" ports. So we will look at a cam in the 260ish degrees@ 0,50" that is either advanced about 3 degrees in its grind or we will advance it to get the desired port velocity. Lets take the FK8. That usually makes 0,535" lift with 1,4 rockers. Lift/valve diameter is about 32% which is good, and also means that you can "use" the ports potential if the engine can make the vacum. (I assume here a 2275 or close)
Now the wedgies flows about 203 cfm @ ,535" Take 90% of 203 and you end up with 182. So, in my book that is the hp the engine should be able to pull and then you will be able to pull good overall torque (We are talking super street, not all out racing) - uuusually this should make it possible to pull close to 100 Nm/1000cc.
Take the same set up, swop the heads to a set of Ultra Mags (The old version) I´m not really familiar with the new version just yet) The port volume on these are about 3 cc smaller than the Wedgies and the ports are made more for midrange power than high rpm power. They flow about 180 cfm @ 0,535". Then the 90% rule says 162. Good. This make the possible port velocity increase with about 15 fps, which means that we are very much in the good zone, which again means that we can take the liberty to retard the cam to say 108ILC. to take advantage of the later closing of the intake valve. This again means that we have a good chance of using the potential of the cylinderhead better and expoit its flow capacity further against its limit. so with the cam set up at 107/108 ILC this engine can/will pull 175-180 hp max and the usable torque band will be much wider, also the peak torque will typically increase to about 109/111 Nm/1000 cc. It will fall off sooner after peak hp. But you do not need that unless you are stoplight racing and want to bragg about how high you can rev it, you just shift to the next gear and let it pull.
Again, all this is as you know only part of the equation. But it may help explain why some combo´s work so much better than the next that looks to be aklmost the same.
T |
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UK Luke 72
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Joined: September 07, 2011
Posts: 2867
Location: Little Britain
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fivelugshortaxle
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Joined: May 13, 2011
Posts: 4254
Location: Aumsville, Oregon
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| Posted: Fri Nov 10, 2017 7:10 am Post subject: Re: 2276/86b beetle daily |
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| UK Luke 72 wrote: |
If you're NOT writing a book T... 
I could listen to you all day long  |
Yep. I search for any new posts of his every time I log in.
_________________
Good things come to those who wait.
2332 with lots of goodies....
Rotating assembly balanced by Brothers VW
4340 84mm crank
AA 94mm p&c' s
Total seal 2nd ring, rest are Grants
5.5 h beams
Magnum straight cuts
Steve Long XR310 on a 106
CB 1.4 rockers
CB Magnaspark 2 distributor
NGK D7ea plugs
A1 lowdown 1 3/4 with single muffler
Dellorto 48's with 40 venturies
Kennedy Stage 2 with Daiken disc |
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Spike0180
Samba Member
Joined: June 06, 2015
Posts: 2269
Location: Detroit, Michigan
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| Posted: Fri Nov 10, 2017 2:05 pm Post subject: Re: 2276/86b beetle daily |
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| Alstrup wrote: |
A good friend of mine built a 3 liter dragrace engine about 4 years ago, with super long 6" rods after recommendations from several race engine ace´s. (It gave 1,78 RR) I was´nt really convinced that this was good, but hey, this was a race engine. different rules apply. - Or do they(?) Put to the test it turned out that this beast was EXTREMELY difficult to tune, but when they found the sweet spot it pulled 320 hp @ roughly 8000 and reved to 8800. BUT, the crank broke soon after.  Upon disassembly he found several things that indicated severe flex in the engine. After about a year and some discussions across the continent we decided that the next attempt should have shorter stroke to make the crank stronger, and also shorter rods to make the engine sturdier. So we decided on a 80 mm stroke and 5,5" rods. making it 2,8 l. Same everything else. This engine was much easier to tune, -AND made 318 hp still at 8000 rpm (!) Food for thought.[/color]
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It sounds to me like the engine was inefficient due to case/crank flex preventing it from reaching full potential. So I have reserves about your claim on the effects of Rod length.
_________________
Brutis Patches Izabich: 1970 VW Transporter - 1776cc DP
Current State: Projects never truly end...
Location: Grosse Pointe, Michigan
Other cars: 2003 F150, 2003 Jetta GLI vr6-6sp
Sambastic: adj; the quality of being nit picky, elitist, expecting everyone to do things the way they believe is best with no regard to situation, "sambastic" |
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hobbybob517
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Joined: June 02, 2011
Posts: 1194
Location: Netherlands
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| Posted: Mon Nov 20, 2017 1:43 am Post subject: Re: 2276/86b beetle daily |
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Any updates? 
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THE BUILD http://www.thesamba.com/vw/forum/viewtopic.php
| SBD wrote: |
3 million rpm? Well there's your problem! No wonder it blew up! |
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UK Luke 72
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Joined: September 07, 2011
Posts: 2867
Location: Little Britain
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fivelugshortaxle
Samba Member
Joined: May 13, 2011
Posts: 4254
Location: Aumsville, Oregon
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| Posted: Thu Dec 14, 2017 2:43 am Post subject: Re: 2276/86b beetle daily |
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How's this build going?
_________________
Good things come to those who wait.
2332 with lots of goodies....
Rotating assembly balanced by Brothers VW
4340 84mm crank
AA 94mm p&c' s
Total seal 2nd ring, rest are Grants
5.5 h beams
Magnum straight cuts
Steve Long XR310 on a 106
CB 1.4 rockers
CB Magnaspark 2 distributor
NGK D7ea plugs
A1 lowdown 1 3/4 with single muffler
Dellorto 48's with 40 venturies
Kennedy Stage 2 with Daiken disc |
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UK Luke 72
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Joined: September 07, 2011
Posts: 2867
Location: Little Britain
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Paul.H
Samba Member
Joined: April 03, 2015
Posts: 613
Location: England
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| Posted: Thu Dec 14, 2017 7:25 am Post subject: Re: 2276/86b beetle daily |
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| A few yars ago I decided to do some dyno tests to find out exactly how important valve lift was in the real world of the street motor so by merely swapping the rockers which were Scat 1.25 v Scat 1.4 (more like 1.3 and 1.45).The difference was negligible and certainly not worth the extra wear and tear on the valve train. Over camming is a common mistake made by many newbies |
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UK Luke 72
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Location: Little Britain
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Paul.H
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Joined: April 03, 2015
Posts: 613
Location: England
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| Posted: Thu Dec 14, 2017 11:27 am Post subject: Re: 2276/86b beetle daily |
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| Depends how many trouble free miles you want from the engine |
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Alstrup
Samba Member
Joined: July 12, 2007
Posts: 7216
Location: Videbaek Denmark
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| Posted: Thu Dec 14, 2017 11:53 am Post subject: Re: 2276/86b beetle daily |
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| Paul.H wrote: |
| A few yars ago I decided to do some dyno tests to find out exactly how important valve lift was in the real world of the street motor so by merely swapping the rockers which were Scat 1.25 v Scat 1.4 (more like 1.3 and 1.45).The difference was negligible and certainly not worth the extra wear and tear on the valve train. Over camming is a common mistake made by many newbies |
I do not nessessarily disagree. But it has a lot to do with whether the engine can exploit it or not.
For instance, a 2332, 86c cam etc etc., with 1,25 rockers. versus the same engine with 1,4 rockers. It is a full 4/10 second faster on the quarter with the 1,4´s. In that set up it pulls just shy of 200 hp. and a solid 260 Nm torque. Naturally lift, and a lot of it has some impact on valve train life. |
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Paul.H
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Joined: April 03, 2015
Posts: 613
Location: England
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| Posted: Thu Dec 14, 2017 12:14 pm Post subject: Re: 2276/86b beetle daily |
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Maybe on that engine it would make more difference but I was testing on 2110 street motor with FK8 and efi
Maybe it was an FK10-can't remember |
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UK Luke 72
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Location: Little Britain
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UK Luke 72
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Location: Little Britain
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