911S powerband, 904 Carrera powerband, "Mulsanne powerband".....

[Jim Ratto]

how does it drive then John?
is it more linear or something?

I ran the 86c in my 2276cc with same heads I have on my 2165... the Lonnie Reed look-a-like welded Denham 44 x 37 heads, with 48IDAs, 9.3:1, and Scat 1.4 (1.5) rockers.... dialed lift was damn near .600" at valve. The car was NOT cammy, as those that drove that car around besides me can attest (hi sheep, SODA and kafercup). It would just MOVE when you stepped on gas, even off idle. I remember picking Sheep up for work one day and we were getting on freeway onramp. I was cruising under 3000 in 2nd gear, stomped it and sent the ass end of car sideways in a haze of smoke and Sheep was dying laughing, he was saying "Dude, you've made this car so fucking fast you can't even control it any more"
This was also the cam that was in my car that took all the color out of my ex-boss' face when he drove the car (Jerry) and also the cam the earned the compliment of "this car feels like it is going to rip the seat rails off of the pan."

I love the 86C, and if I lived closer to OC and didn't drive the wheels off my car, I'd run it. But since I put around 8000 miles a year on my car, I want to keep lift conservative, hence the Pauter cam with 1.25's. For what it is worth, I did run the 86C with 1.25 for ONE week and it didn't have any bark to it, I personally think the 86C needs 1.4's + to make it scream.

[Peter]

HAHAHa this makes me laugh
good story

[Chris Andrews - The Mailman]

Oh no, not another post from me.  Right? Sorry to bog everybody down with techno-number posts....just want opinions, before my brain runs into redline and drains out of my ears.

Considering a few older Porsche high-output engines, specifically:

911S 2.2L: 180hp@ 6500, 84 x 66mm, 320' duration @ .15mm, 82hp/liter (366cc per cyl)
904 (587/3) 2.0L: 185hp @ 7000, 92 x 74mm, 352' duration @ .15mm, 94hp/liter (492cc per cylinder)

Obviously, Porsche saw the need for some generous valve overlap to achieve power, especially, considering the valve timing on the 911S was the same used on the smaller 2.0 6 cylinder. While I've never driven a 904 and never will, I have driven a few early 911's, my most vivid memory was the 2.4 1973 that McKenzie owned for a while. The powerband of that engine was thrilling.

So my question, considering the weight and stock 4.37:1 gearing of a Type 1, and your typical 94mm stroker engine, how would you duplicate the "powerband" of the old 911S or 587 4-cylinder motors? Not that horsepower numbers need to match, meet, exceed, but that the "camminess" and surge above 4000rpm resemble them. With the light weight of the VW, and the relatively "short" gearing of the 4.37 box, AND with the torque made by a 2.2L+ 4 cylinder (550cc per cylinder), a large amount of duration should get the car off idle fairly and give the "rush" above 4000 as well, right? But how much is enough, too much, just right? The Porsche cams were checked @ .006", we check at .050"...
Some sources list 911S cam intake duration @ 267' @ .050".... Engle 130? Of course, the VW motor has much bigger lungs to fill... (550cc vs. 366cc)...

again STREET motor.
ANY thoughts, feedback would be appreciated. Thanks guys,

Jim

Jim,
Check out this URL http://www.aichlseder.info/bilder/2_ohc/1.htm Pay close attention to the cylinder bore vs stroke, HP vs RPM. An awesome engine.

[Jim Ratto]

anybody watch GT Racer on HD theater channel lately?
if you have heard some of these sports prototype motors at high rpm, you know what I'm getting at.

More talk on this subject?

[alex d]

Oh no, not another post from me.  Right? Sorry to bog everybody down with techno-number posts....just want opinions, before my brain runs into redline and drains out of my ears.

Considering a few older Porsche high-output engines, specifically:

911S 2.2L: 180hp@ 6500, 84 x 66mm, 320' duration @ .15mm, 82hp/liter (366cc per cyl)
904 (587/3) 2.0L: 185hp @ 7000, 92 x 74mm, 352' duration @ .15mm, 94hp/liter (492cc per cylinder)

Obviously, Porsche saw the need for some generous valve overlap to achieve power, especially, considering the valve timing on the 911S was the same used on the smaller 2.0 6 cylinder. While I've never driven a 904 and never will, I have driven a few early 911's, my most vivid memory was the 2.4 1973 that McKenzie owned for a while. The powerband of that engine was thrilling.

So my question, considering the weight and stock 4.37:1 gearing of a Type 1, and your typical 94mm stroker engine, how would you duplicate the "powerband" of the old 911S or 587 4-cylinder motors? Not that horsepower numbers need to match, meet, exceed, but that the "camminess" and surge above 4000rpm resemble them. With the light weight of the VW, and the relatively "short" gearing of the 4.37 box, AND with the torque made by a 2.2L+ 4 cylinder (550cc per cylinder), a large amount of duration should get the car off idle fairly and give the "rush" above 4000 as well, right? But how much is enough, too much, just right? The Porsche cams were checked @ .006", we check at .050"...
Some sources list 911S cam intake duration @ 267' @ .050".... Engle 130? Of course, the VW motor has much bigger lungs to fill... (550cc vs. 366cc)...

again STREET motor.
ANY thoughts, feedback would be appreciated. Thanks guys,

Jim

The more I read about the 904 the more I like it...oddly enough I havent' been able to find the valve size specs for it...google actually directed my to this same topic, go figure! anyone know the valve sizes for the last 4-cam iteration?

[Fastbrit]

The more I read about the 904 the more I like it...oddly enough I havent' been able to find the valve size specs for it...google actually directed my to this same topic, go figure! anyone know the valve sizes for the last 4-cam iteration?

Inlet valve = 49mm
Exhaust valve = 43mm
 

[Zach Gomulka]

The more I read about the 904 the more I like it...oddly enough I havent' been able to find the valve size specs for it...google actually directed my to this same topic, go figure! anyone know the valve sizes for the last 4-cam iteration?

Inlet valve = 49mm
Exhaust valve = 43mm
 

That's one heavy breathing two liter.

[Jim Ratto]

you should see cam profiles.....

[Zach Gomulka]

you should see cam profiles.....

Go on...

[Martin S.]

Big lift with 42 x 37 valves in my 2332 is part of the reason my engine makes the power it does. A top fuel racer friend of Steve's was surprised how much cam is in it when he checked out the car. You can see the lift for yourself in this vid... https://youtu.be/xX3iaHUI-SA

[bilboa2]

ok, a little input from my experience on sportomatic 911's and cam changes. Living with roger grago at the time when he had his first auborgine 70 911t with 40m/m webers. I wanted to go the 911 life. Mark Thurber was just finishing his red 1972 911 Carrera look. I liked. I wanted one, so sold the  63 aronson / holmes  white car and bought a 1972 911t 2.4, (first year t with mfi). (Both same price  $4k !!!) Car was a sportomatic . Was a fair at best respray white, originally condor green (??)  stock hp was 140 for my car. Also mfi t's where yellow fanshroud, e's green, s red. 1973.5 and later t's where cis injection. Raced against rogers 2.2 , he had me till about 45, then I pulled away. The sportomatic was tricky to drive, but learned to get your hand of the shifter asap. 2.2 to 2.4 was bigger due to stroke. WE then pulled my car apart and I turned it into a 210 h.p.  2.7 euro Carrera spec motor. bigger 90 mm bore,  Sent heads for bigger valves etc to ollies and injection pump to farchild in san francisco for new pump cam and updates.  Porsche specialist Wayne Witten in santa ana built the motor. Wayne came from porsche dealer and had experience tuning the iroc 2.7 911's. I also put a manual trans in it. Repainted it in grand prix white with the new just out there black powder coating trim. I had an early set of the early 7 inch fuchs in the rear,  RARE, Now on the front of rogers 911..... sorry, back to rpm, cam choice. I don't know cam specs, but 2.4 t was done pulling around 5800. The 2.7 was crisp to 6800, 7k, still had good trq down low. ( stroke ?). In paris/dakir style races I believe porsche used sportomatics. They even had sportomatics in 914 sixes. What a difference in car  rpm changes, just ask my insurance company. After to many run ins with the law I sold car for 18k thinking I got the world for it. (through dyno don of course.)  I can't believe the price of the long hood 911's (-73)!! .  As far as vw cams in a 2276cc, 4 speed, pump gas, I would lean to a web 86 b or maybe fk44 spec at most. Jim,  I like/respect your cam thoughts, sounds like your pushing towards more air speed and drivability cam choices ??.   sorry for ramble.  But, as just getting home from orange county road trip with 2 large coffees still in me. Also remembering the ride in clyde bergs daughter's street black 65 vw with his old fk 89 race motor, now on e85. CRAP , That is some e ticket ride. He has a real cool kinda safe (lol) test drive loop.. He said low 11's if it hooked up. FUN  ok, everyone go ask for a ride.... Cam choices ?...GO BIG  take care,  bill

[bilboa2]

later thoughts... sorry as I think I rambled on this car/motor before. Back to rpm range, I remembering reving  the 2.7 high to 6800 or so, a bit past its peak pull, but matched up to the next gear change better as I had a 4 speed 901 trans in it. Hot vw's are still a favorite, but the early 911's can really rock. Sometimes there's a corner ahead....To bad they are stupid priced now.   

[alex d]

49mm valves on a 92mm bore....canted valves and OHC would definitely make our lives easier...but then we like challenges I guess 

I recall reading somewhere that Porsche tested 48 IDAs on the 904 and they considered them too big so they stuck with the 46s...I wonder what they'd think of us using them on even smaller engines!