Gettin' Max Power

[hombre]

How do you get max performance out of a Supercharged R3? By adding 11 degrees of overlap to your cams, of course. It amazes me that other places expect big numbers from just popping on a SC and using a pre-packaged tune. It all has to work together, boys.

BTW, that all the cam specs I'm allowed to reveal. If anyone wants SC cams, contact Nev: nlrace@bigpond.com

 

[trackerjack]

The stock R III engine is designed to be a torque engine and not a high power engine.
So the stock cams come with a torque profile with an Intake 12° BTDC and an exhaust 11° ATDC.
That's a small amount of overlap to respect that objective.
(the shorter the overlap period for a given engine, the lower the Rpm at which the engine will develop maximum torque)

For sure, the stock cams specifications are not the best for a supercharged R III engine and the overlap is not the only one.

But SC + cams are much more expensive than the SC alone and unfortunately, that's often the wallet specifications that determine the degree of engine modifications !


Ps : sorry for my exotic English.

 

[hombre]

Good point, Jack! (Your English is perfect)

Here's some observations from my friend Wayne (dragline):

Duration: The better duration of SC Cam .... ups rpm range = good which lessen Tq a bit in lower rpm range , which would compensate for added SC POWER a bit = better for traction launching .

Increased Lobe center SC cam : Better more rapid gain in TQ & HP and tends not to drop off as fast , after say 2000 rpm of stock cam + a wider lobe separation holds longer = less hp & tq drop in upper rpm range which you will need for Maxton run

VALVE LIFT : Is fine , don't really need a lot more lift with SC as a/ f ratio is forced in cylinder under pressure , which creates more heat , therefore don't need to fly cut pistons , with a wee bit more lift . As in car engine .090 clearance intake .100 exhaust clearance usual with out fly cutting piston

One very important thing I learned is LOBE CENTER ( separation ) I 've ran 5000 + cam profiles... After 5252 rpm ( law of physics ) tq & hp cross on dyno. Depending on cam lobe separation , engine can and will lose massive amounts of TQ as rpm's go up after 5252 rpm's , HP keeps rising , but the trick : TQ = amount of work to be done HP = how fast it gets done.

Keeping TQ high as long as you can = moving that heavy R3 ( brick air flow designed ) against head wind cutting through @ 160 + mph PLUS added tq of supercharger = amount of work to be done. 18 " CF rims + Duration = upper rpm's = how fast it gets done.

Think you got a good combo , best of both worlds , considering your not
building a dedicated bike for LSR only .

 

[dragline708]

I have a cam profile computer program
That's pretty accurate depending on engine combo
spec's
Changing lobe separation angles ( spreading lobes )
or leaving a intake lobe alone and just moving exhaust
or vice versa
Duration how long , valves stay lifted
Ramp rate , how fast valve lift .

When I first got computer program , I changed cam spec's
by a .5 degree @ a time on intake & exhaust to see effect
in rpm range it had and effects on hp gain vs tq loss .

You can have the same lobe sepration example 108
on 2 cam profiles , but what important is knowing intake center line
and exhaust center
example 108 intake centerline 108 exhaust centerline added = 216 div by 2 = 108 centerline
The other cam profile has
103 intake centerline 113 exhaust centerline added = 216 div by 2 = 108
all else in both cam profile being identical
That would be completely different hp & tq ranges on a dyno .

I'm rambling , I'll shut up now . Once a speed freak always a speed freak
The Cams the heart beat of an engine, I could talk about engine mods forever

PS: designed my own solid roller cam and had Crane Cams cut it from a blank
billet , they do a run of custom cams about every 2 months to customer spec's

Crawling back in my corner now

wayne

 

[trackerjack]

"The Cams the heart beat of an engine, I could talk about engine mods forever "

Dragline......I love this forum when you speak like this !

It's a good thing for me to know that I'm not alone to be able to speak (in french only ) about engine mods forever.

It's so interesting !

Andrews cams do a run of custom cams to customer spec's very often too !
I've ordered some for HD big bore twin in the past.

What is your cam profile computer program ?
mine is an U.S one from craig Walter's Technologies.

 

[dragline708]

JACK ,

The program I was using is an older model program
Here one of the upgraded versions , click around on it to learn
what can be done with it .
They may have and even newer version out by now.
I just did a quick search
http://www.proracingsim.com/desktopdyno.htm


here the cam profile I made in action


video was made in 1992 when I was 46 yrs old , 16 yrs ago
Little did I know then , I was dragging time with me ( how time flys )

Haven't made anything for the R3 , getting a bit old and worn out
Still have the desire through , the minds a terrible thing to waste

wayne

 

[hombre]

Obviously we need to have a gathering of the serious R3 HP freaks at a central location... my place in Mallorca?

 

[dragline708]

Hombre ,

Only if I you give me a chance to
ride that Supercharged R3 and your
on the back .
After that ride you'll be my age

Once ass end of Anglia was on fire crossing
the finish line Talk about a wild ride !!
Cross finish line @ 120 mph + and can't see a thing ,
because of smoke inside and still won race !
Think guy behind me let off being cautious

wayne

 

[hombre]

I can see that your Anglia was a wild ride from your video... talk about TORQUE!!! Did you ever dyno it?

I don't have any passenger pegs on my SC R3... Jolanta is scared to death of it.

 

[dragline708]

Hombre ,
No never got it dyno'ed other than desk top
read out . which was with in 2 hp & 2 ft lbs tq
Checked it against a friends engine spec's I ran on
desk top dyno , his car was dyno'ed the day before on real
dyno ( roller etc ) desktop dyno VS real dyno dead on accurate.

My anglia read out was 538 hp @ 6500 rpms
521 tq @ 4500 rpm in a 2310 lbs car ( total weight ) including 1/4 tank of gas
and 198 # driver.

wayne