group N cam timing

[bloke]

group N cam timing

finally got round to doing something with cam timing on standard cams. car is a 172 cup, btb exhaust and cat, mtc inlet elbow and cone filter. car always felt strong and pulled well. the red is from it's first power run so we had a start point, was on standard renault map. cam timing was just about spot on.

fitted a new belt kit and set timing up, idled like a bag of crap, kept stalling and idle was too low. nice and lumpy though when it didn't stall!!

cropped and blanked the figures out on the graph as only looking at the difference the cam timing makes and saves people banging on about dynos over or under reading and whoever else's dyno is better etc.

 

[imprezaworks]

Nice.

 

[bloke]

bloody fun to drive now, was good anyway. was in from 6.30 yesterday morning and finished at efi about 9.30 last knight, absolutely shattered but woke me up driving it back!!

 

[NorthloopCup]

I. Rest. My. Case.

 

[bloke]

I. Rest. My. Case.

was interesting to do one at last. definitely worth it though, idle and start up idle took a bit of cheating to work around though :wink:

 

[JamesBryan]

So 197 cams not really needed then?

 

[bloke]

the 197 cams give you more extra power and torque but this is only the first one i've done so wouldn't like to say for now BUT with going for the timing change you don't have to spend out on cams, belt kit and then the fitting so it works out a lot cheaper.

 

[JamesBryan]

What happens timing wise on the inlet with the dephaser, is there a risk of valve to piston contact?

 

[Daz...]

This is something I keep thinking about, seeing a graph back to back really does show it’s worth it.

 

[crazycup_racer]

What is the torque lb/ft difference between the 2? The torque increase from 3k onwards looks fantastic

 

[Fletcher]

I’ve just seen the graph on FB. Impressive power gains!

 

[R3k1355]

Is this going to be offered as a package now?

Belt change, timing change and remap??

 

[green]

Nice one @bloke for sharing :up: I take it it’s just ‘normal’ group n timing and mapping?

 

[imprezaworks]

Yeah how much.....

 

[Daz 172]

I’m looking forward to driving this when I get it back massive thanks to Carl and Chris !

 

[imprezaworks]

Your car, nice

 

[bloke]

What happens timing wise on the inlet with the dephaser, is there a risk of valve to piston contact?

it's not advanced by that much so still clearance. i've seen them that have been out more from having the timing cocked up or it's slipped and still been fine.

What is the torque lb/ft difference between the 2? The torque increase from 3k onwards looks fantastic

was about 5bhp and 7lb/ft but it's the way it shifts it all around the rev range.

Is this going to be offered as a package now?

Belt change, timing change and remap??

would like to do a few more to see what difference it does make on a few cars as this was a strong one to begin with, it's one of those cars you'd call bullshit on if someone told you it:wink:

in theory it could be done without a belt change as it's only cams that are moving but done along with a belt change then no real difference to the job.

 

[JamesBryan]

it's not advanced by that much so still clearance. i've seen them that have been out more from having the timing cocked up or it's slipped and still been fine.

Not too bad then.

Is it more or less the same degree of adjustment as the 197 cams?

 

[bozothenutter]

following this!

how would this fare with a RS2 I wonder.....

 

[bloke]

Not too bad then.

Is it more or less the same degree of adjustment as the 197 cams?

197 is just inlet advanced whereas group n shifts exhaust as well.

 

[R3k1355]

So the 197 cams aren't actually longer duration or higher lift compared to 182, just slightly different timing?

 

[bloke]

So the 197 cams aren't actually longer duration or higher lift compared to 182, just slightly different timing?

the 197 are different profile to the 172/182, got to admit can't remember exact differences as was ages ago i looked and that was just to work out the timing set up on them when using them on the 172/182. they can be fitted on standard timing but you don't get as good a gain from them.

 

[R3k1355]

So which is better, stock cams on Group N or 197 cams (do they need timing in specifically too)?

 

[JohnnyE]

Doner car here for you mate......

 

[bloke]

So which is better, stock cams on Group N or 197 cams (do they need timing in specifically too)?

197 cams will give more overall power and torque but torque will be higher up the rev range. would like to do a few more on this timing before answering that one though but from how this one is for road use i'd be tempted to say group n timing but for competition/track car then the 197 cams.

the 197 cams have their own specific timing when used in the 172/182.

 

[NorthloopCup]

was interesting to do one at last. definitely worth it though, idle and start up idle took a bit of cheating to work around though :wink:

I think everyone thought I was a liar when I said just how much of an improvement it makes tbh mate. Who's got egg on their fuckin face now then eh?
Idle speed is easy to fix!!

 

[bloke]

I think everyone thought I was a liar when I said just how much of an improvement it makes tbh mate. Who's got egg on their fuckin face now then eh?
Idle speed is easy to fix!!

yeah, sorted with an added air leak :wink:

was mainly when it was started it would just cut out straight away even with idle set quite high.

 

[497adam]

So interpreting the graph - gains from 3k with lots more torque to 5k and holds on past 6.5k a lot better?


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[bloke]

Doner car here for you mate......

is that like a donner kebab :tongueclosed: will have to look at your cam specs actually and see if it's worth doing anything with them?

So interpreting the graph - gains from 3k with lots more torque to 5k and holds on past 6.5k a lot better?

yup or to put it in layman's terms...goes like stink from 3,000rpm

 

[JohnnyE]

Sound mate keep me informed

 

[imprezaworks]

Any ideas on costs

 

[bloke]

Any ideas on costs

cheap for you :wink:

 

[imprezaworks]

X

 

[JP83]

cheap for you :wink:

What about if we bring cookies?

 

[bloke]

What about if we bring cookies?

not that fussed on cookies sorry

 

[Greeny.]

Out of interest, what makes this 'group n'?

 

[bloke]

Out of interest, what makes this 'group n'?

stands for nnnnnnnniiiiiiiiiiiice :tonguewink:

group n was advanced inlet and retarded exhaust cam timing, all that was allowed. basically to try and take best advantage of the standard cams.

 

[Greeny.]

stands for nnnnnnnniiiiiiiiiiiice :tonguewink:

group n was advanced inlet and retarded exhaust cam timing, all that was allowed. basically to try and take best advantage of the standard cams.

Good to know

That makes peak bhp really high up the rev range doesnt it, my 421's make peak at around 6700 in comparison

 

[bloke]

Good to know :smile:

That makes peak bhp really high up the rev range doesnt it, my 421's make peak at around 6700 in comparison

the graph is smoothed, on the first one from 6,200rpm it only goes up by 5bhp to peak power. there is a slight dip at 6,500rpm otherwise it would of hit peak between the two figures and held right through.

 

[497adam]

cheap for you :wink:

That was my next question [emoji6]


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