how far can you go with the stock cam?

[Adey aka Ewok]

how far can the stock cam be pushed? whats the fastest qm trap speed had on one? ive maxed out the float chamber in the carb before reaching full dyno results, tho im now working on my second fuel supply to try and cure that

[phase i 16 v turbo]

RS250Nut did quite well on his last build

[Adey aka Ewok]

well i got doing 106mph terminals in a 5 with the stock cam, we went for big boost on the dyno but couldnt get passed 4500rpm in 4th but was looking very good for well past 200bhp, would love to see how fast u can go on the stock unit, think someone mentioned ages ago that 108mph has been the fastest trap on a stock cam tho i could be very wrong?

[Scoff]

I think ant @ backyard managed 108mph. I've never seen more than that! you find the stock cam will make as much torque as you like, so it might have looked great at 4500rpm but they just won't breath at high rpm's once boost gets lairy.

[Adey aka Ewok]

ahh cool so not much left in it then, could it be timed differently or is it not worth the agro?

[The new Bill J]

Dare I say Roly, from GT Tuning.....

[Scoff]

Dare I say Roly, from GT Tuning.....

I try to only use data from reliable sources :) If he really did (which I'm not sure I believe ?) then he did well, but he won't have been able to do it on pump fuel, I'm certain of that.

[Adey aka Ewok]

Dare I say Roly, from GT Tuning.....

Explain?

[The new Bill J]

Explain?

He reckons he ran the standard cam, when he set his time of 12.6 @ 112mph.

[Karlos]

Dare I say Roly, from GT Tuning.....

He's got a T-Shirt to prove that the proof is in the pudding :rolleyes:

[J$£5GTT]

He reckons he ran the standard cam, when he set his time of 12.6 @ 112mph.


i remember that,always bangin on about the oe cam...

[firstchoicegary]

mine ran 14.2sec at 100 mph standard cam

[Rob@Backyardracing]

He reckons he ran the standard cam, when he set his time of 12.6 @ 112mph.

Ballocks.... just cant see that trap do able with OE cam

[Adey aka Ewok]

so if im pushing the stock cam 108 is the goal? im sure i read somewhere about retarding or advancing the cam to move the power band, has anyone tried it with the stock cam?

[Rob@Backyardracing]

I think the most we managed was 109, this was with stock cam timing, t28 25psi, 30hp (there abouts) Nos gain...

You can shift the cams power band by advance or retard yes..

Heres somthing that mite interest a few, ive tried both extremes on a car running a t28 25psi, piper 285, 25hp gain.. same weather conditions/same day, same rpm and gear changes.. fully advanced fastest trap was 106mph, fully retard 116mph.. Im not saying fully retard is away to go at all you must dial your cam to suit its spec and use, this was just a practice lesson i wanted to know.. Wish i saved the ticket to see the 1/8 i really cant remember..

[rs250nut]

RS250Nut did quite well on his last build

What I thought to be a 260-270 piper from k-tec was a standard cam and I managed a 108mph pass
might have gone a bit quicker too if I had not of bottled it with the boost:crap:

[Adey aka Ewok]

so would you try the same with a stock cam? and what would you retard it too for top end power?

[Sparkie]

isnt 4deg about right?

[Adey aka Ewok]

duno sparkie, ive never done any cam work atall, how would i do it, put a vernier on on can i just jump it one tooth back?

[TommyB]

My best so far is 108.21.

That was with nitrous.

[Adey aka Ewok]

How many teeth are on the cam pully?

[Logg]

Didn't Colin say ages ago if you use the stock pully the wrong way round it'll retard the timing by a couple of degrees? or was it advance bloody hell I can't remember!:scared:

[markey b]

13.8 @ 105mph with stock cam and road tyres, but hoping to get better this year as my driving was appauling when i got that

[Adey aka Ewok]

I'll give him a shout and find out

[Adey aka Ewok]

So what way is advance and retard, clockwise and anticlockwise on the cam are what? If I twist the cam clockwise does that make it advance?

[Scoff]

yes, turning the pulley over will give about half a tooth of adjustment. It's up to you weather you choose to advance it half a tooth or retard it. I don't think there will be a lot to gain with the standard cam, but definately worth a shot, if only to see what happens :)

[Scoff]

retard would be to turn the end of the camshaft anti clockwise with the pulley stationary. Or, moving the outer of the pulley clockwise while the cam stays still. Count the teeth on the cam sprocket, divide 360 into it, then divide by 2 to get into crank degrees. One tooth will be quite a bit, I think half a tooth retard will be worth a try.

[Adey aka Ewok]

It's more to see if I can move the powerband higher in the revs, plus Its stock bits so only cost me my time

[Adey aka Ewok]

10.5 ish degs per tooth, so if flipping it gives half a tooth advance? I could flip it and and jump it one tooth back to give 5 degs retard? Or have I just confused myself?

[Scoff]

10.5 ish degs per tooth, so if flipping it gives half a tooth advance? I could flip it and and jump it one tooth back to give 5 degs retard? Or have I just confused myself?

yes, thats it.

[Scoff]

except I just spotted I wrote that wrong :crap: You count the teeth, divide 360 into it to get cam degrees. Multiply by 2 to get into crank degrees, not divide :) half a tooth is quite a bit of timing still, you want a vernier really.

[Adey aka Ewok]

Are there the same amount of teeth on the crank pully and cam pully?

[rs250nut]

No there are less on the crank pulley

[Scoff]

Are there the same amount of teeth on the crank pully and cam pully?

engine's 101 :D no, half the teeth on the crank, so twice the rotational speed.

[Adey aka Ewok]

What an idiot, had that convo already today, cheers scoff, if the weathers ok I might take a look this weekend