Ignoramous Info required on Cams and Tuning ???

poormansporsche

alright peeps

basically what i know about engines can be wrote on the back of a postage stamp !!!

Ive been reading through the forum and talking to my local mechanic (who is a cosworth tuner) and now im more confused than ever

anyway, ive ordered a milltek system and a sports cat to be going on with, ive printed off the air box mod instructions and will be getting that done, im trying to sort out the 2.4 manifold and TB.

But my major confusion is over cams, my mechanic has said he will be able to port and sandblast my head no problem but he says it not worth doing unless you fit cams

so if someone could explain to me :

1, if i have my original cams reprofiled - what does that actually do?

2, If uprated cams are fitted - what does that do?

3, why is it that with some cams they have to be "matched" to the head or additional head work is required

4, I have a vectra B so apparently some cams need hydraulic lifters, what are these and are they expensive?

basically the driving 95% of the time is the slow commute to town, I do not drive on motorways so im not bothered about any top end performance, what i actually want to achieve is more grunt on the 2nd and third gear country lane blasts without revving the nuts off, and ive heard that some cams you lose bottom end performance ???

cheers

Brett

luna_s

1) when they reprofile your cams, they add / take away material to increase duration and lift
2) makes valves open higher and longer for more intake / exhaust, which increases bhp and torque
3) dont worry about it with piper
4) car already has hydraulic lifters so no need to worry 😃

the piper cams have a good rev range (2400 - 6800rpm) iirc with about a 10bhp gain on their own - no top endedness - will work very well with the 2.4 inlet too

poormansporsche

cheers, so what does this mean then (taken from courtenays !)
"""""""""""""""*2.2 cams include double valve Springs and collets and require head machining work. Vecta B +£200 to include additional camshaft re-work required.""""""""""""""""

so what is the extra work needed on the Vectra B?

Cheers

luna_s

double valve springs help avoid valve bounce/float.

im not sure of the specs of the courtenays cams but the piper cams dont need them.

vocky

that's the schrick cams, they need extra work and cost triple the price :?

fitting cams at the same time as porting the head gives a nice power increase showo..

markv

The lift the cam gives seems to be the issue. From what I've learned the limit seems to be 11mm. Usually when cams approach that level of lift suppliers start adding the modification to the parts list. With the shrick cams you're talking about 12mm of lift if I'm correct. So that would mean modification. With the Piper's you're talking about 10.74mm, so no modifications needed.

Cam's generally do two things, they change lift (how far the valves are pushed out) and duration (how long the valves are pushed out). The lift is displayed in mm's and the duration in degrees (I know that I'm simplifying, but it is a good way to get a general idea).

The standard cams are 9.5mm lift and 245 degrees duration. If you compare that to shrick and piper you see a different approach:

piper: 10.74mm lift, 266 degrees
shrick: 12mm lift, 252 degrees (as far as I know)

So they have a different approach. Which works better or gives what characteristic, I don't know.

Mark

poormansporsche

my mechanic reckons he can "machine" the cams whatever that means ?????????? is it worthwhile just getting the piper cams ??????

JohnnyN

I've got Schrick cams fitted by Courtenay. They are part of the CS5 package and I am very happy with mine.

thumbup

poormansporsche

so what this about the hex bolt jobbie on the vectra? do have to get cams specifically designed for the vectra or can i use any z22se cams - ala astraandys dblilas fast road cams in the classified section !!!!

luna_s

hex drive is for the power steering pump - its bolted on the end of the cylinder head directly to the camshaft

jimmywrc2_2

cams

the othere day i got talk n to a chap who remaps astra turbos! he said to me not worth put in camz in mine it will alter the emmission 2 much not run even dunno.. but then he said not worth remap n it will only put 5bhp on who is right who is wrong? is it time 2 say good bye to the 2.2 and hello turbo ? or wot about turbo conversation? 🙁

vocky

he's talking bull about the cams, mine have passed 4 mot's 🙂

he is correct with the remap, 5 bhp tops is all they will give :roll:

jimmywrc2_2

vocky said:
he's talking bull about the cams, mine have passed 4 mot's 🙂

he is correct with the remap, 5 bhp tops is all they will give :roll:

so is it really worth the remap ? wot does ur car tick over like smooth with the cams in ?

zafman

mines passed 2 m.o.t.'s with the piper cams.tickover...lumpy 8)

vocky

the tickover isn't a problem, it is caused by too much flow at low revs :roll:

it gives the engine a nice exhaust note 8)

xinitialz

a good remap will add about 10bhp,but in a naturally aspirated engine thats not much and also its not in top end range where the power will be added. at top end u will hardly feel a difference, so dont expect a faster 0-60 time.

What it does is work away the flat spot at 2500rpm and give u more torque in lower revs thus meaning ur car will drive nicer around town. So that turbo guy is right by saying its not worth it if u want to go fast, but considering ur driving style i would recommend it.

oh yeah if u really want easy power then u've got the wrong engine, u need a turbo then simple as that cuz the turbo has 250nm torque from 1950rpm till 5400rpm so when u do 50mph in 5th and u push down the pedal it will still pull nicely. Plus by just remapping it u should be able to get 235-240bhp out of it so well... enough said 🙂

slindborg

A high lift low duration cam (like the schricks) will have a very harsh ramp rate (ie how long it takes to get the valves open to max lift), this will mena that the valve springs and lifters take a much harsher battering than usual. Generally fast ramp rate cams require solid lifters, but you can get away with it as schrick seem to have done.

a low lift long duration cam is the other way round, its far gentler to the valve train, and can still flow the same ammount of air (in theory), but in general terms a high duration cam will effect idle a bit as the overlap duration will be high (where exhaust and inlet valves are open at the same time at the top of the exhaust stroke for scavenging) causing excess exhaust gas to remain in the engine.

catcams offer some great cams and a MASSIVE selection all made from blanks. Available from Jam sport in northampton amongst other places. I was quoted under £500 for a set...

davemate

the cams part i now understand. but whats the deal with the head work. i understand that fitting the cams is quite easy, so i plan to do this. but it it worth doing any of these other things like head work and porting? i mean in a £/HP type way.

slindborg

head work is a nice compliment to cams/inlets etc but isnt vital.... especially if you CBA to get the head off the engine etc.

But most places charge the earth for head work and generally provided a crap service...
I use a guy ive always been to for head work (lol), hes not a pro but he certainly does a 90% pro job for 30% of the cost.

davemate

what difference does it make and what cost from you place slindborg?