Clio 172 without VVT?!

[Keydogg]

As some of you may remember I was complaining because my GF's 172 felt quite underpowered. Well I had it fully serviced at a nearby reputable garage last week, with new sparks (which on the invoice cost £12.75 for 4, is that right?), filters and such, and 10w30 Torco SR1 Fully synth oil.

I was hoping all of this would make a big difference and get the 172 upto standard, and whilst it does seem pokier, I'm still not convinced its as powerful as it should be.

Anyway, one thing stuck in my mind. The mechanic said to me "Your clio isn't a 172"

so I said "why?" knowing full well that it is..

and he said "because the my mechanic who worked for renault for 3 years said it doesn't have VVT, and a 172 should have VVT"

so I said "wtf?"

so he said "sorry mate but it isnt a 172, its just a 2.0l 16v"

so i got the documentation out and the model for the car is "CB1N0F", and the original paperwork with all the details said things like "124kw Max power" etc etc so I proved to him that it is infact a 172. I also told him renault didn't make another 2 litre which wasn't a 172 in this shape.

Anyway he agreed and said his mechanic must have made a mistake, but it got me thinking... Is this something to do with it lacking power? I mean I know it sounds stupid but are the cams not shifting and that's why I'm not getting the power output I should be?

I hope you can all shed some light on this!

Cheers

Al

 

[Gray]

hmmm.. does sound a bit weird! whats the mileage and history of the car?

Have you got a photo of the engine bay just to clear things up? and determine its a 2.0 16v haha

 

[Dan@SJM]

they did make a 2.0 with out vvt. but it wasnt in the clio it was in the espace and laguna etc. its only 130bhp aswell iirc

 

[cat171]

How do you know that your gf's 172 lacks power ??
Is it considerably slower than other 172's ?

Tbh I think the mechanic is talking out of his ass.

 

[Fred@BTM]

wrong spark plugs mate! they're £13 EACH!!!
wrong oil too, its a 5W40, 30 is incorrect

i bet the timing is out or your have a sensor fault

 

[P111LTL]

As yozza say unless someone has transplanted a laguna 2.0 int here its definately 172. I would take it on the rollers if you want to know what shes making wouldnt advise this if the timing is out or your not happy with how shes running and im not on about power out put. Let us know how you get on

 

[Christopher]

there was someone on here who had the only 2.0 15v 172 in the UK

it had a sticking valve iirc

he always wondered why it was down on power compared to others!

can't remember his name, but it could be the same problem?

 

[J0sh]

Sorry to sound dense, but what dose VVT stand for and what is it?

 

[Bash]

variable valve timing

 

[Jay]

I'd stick it on the rollers, and if it is down sell it and buy a proper one

 

[Clioman51]

My 172 had the timing slighty out and I thought it was normal but when I had the cambelt done the bloke said it was out and he'd sorted it. Now it feels sooo much better its like it used to be between 5-7k all the way through with a second wind even better after 5k. So it might be something like that?

 

[Bradharding]

Sorry to sound dense, but what dose VVT stand for and what is it?

Variable valve timing is basically what it says. It allows the valve lift/duration to alter, i.e. increase if you were to put your foot down.

 

[Fred@BTM]

the vvt isn't there for power though (wel in my eyes anyway!)

the 15V 172 was one of our customers, it had 150bhp from new!

the timing can be 1mm out and the car be 20bhp down

 

[-Leigh-]

Yeah but if it had an engine transplant with a laguna engine, it would be down on power?

A pic of the engine should sort that idea.

 

[Fred@BTM]

yep

 

[ben24]

pics pics

 

[edde]

Its happened before usualy as a bodge job before the cars quickly sold.

Pics though woiuld be good check the engine details on the front of the engne down by the oil filter.

 

[Day]

It's not conventional VVT

172 5k kick by BenR 2006

By no means is the 5k kick the result of any mechanical/electronic chance withing the engine system, whether that be mapping paremeters or valve timing.

I think to fully understand, a base understanding of the operating system of the vvt is needed. The vvt system employed on the clio is what we refer to as cam phasing, this is where the whole camshaft (inlet or exhaust or both) is advanced/retarded. This can be in a single step as it is in the clio (single stage 16 degree advance on the inlet), or variable. The camshaft is hollow and is used as a galley to feed the front pulley (called a phaser) with oil pressure, this pressure simply acts on vanes inside to rotate it in a desired direction, and returned under mechanical pressure. The cam does not always carry oil pressure, but a vvt switch is used, and is basically a plunder activated by 12 (grounded by the ecu (a lowside switch)) which allows the passing of oil from the lifter galley to an area of the cam bearings with holes that can feed the inside of the cam, which then passes through to the nose of the cam and into the pulley (phaser).

Variable setups (like the new 197) will use the same base components as what is used today, but instead of the vvt plunger being used as a switch, the same plunger has the ability to open and bypass oil to either side of the vanes in the phaser. By using a PWM signal, you can gain full control of the phaser to advance the cam in a near infinately variable curve vs rpm vs manifold pressure vs throttle angle etc.

Honda's Vtec system is a cam 'changing' system where the actual cam profile is changed in its entirety (hence the 3 lobes per cylinder), the actual 'timing' of the primary lobe remains the same at all times. And now with I-Vtec and VVTL-i the benefits of both phasing and changing is being used at the same time to build some monster VE (volumetric efficiency) curves.

Anyway, in the clio the cam sits in its dephased state until the required parameters are met. This is above 1450rpm and 800mb manifold pressure. When it is required though, the cam is phased and the cam timing effectively advances 16 degrees, at 6800rpm it is dephased again and power drops off like a stone. No official reason, but my thoughts are that they do it so you guys shift up once there is a loss of acceleration. The reason for that is because the stock pistons just fall apart with prolongned high rpm use.

The 5k kick is the result of a few natural phenomenons within the engine. At 5000-ish rpm VE suddenly reaches a higher %'age and the resultant torque increase gives you that wahey feeling. VE increases due to the cam comming 'on'. This term has nothing to do with VVT and is quite an old term, whereby the reference is to the rpm region that particualr engine/cam combo requires to process the valve timing events efficiently.

VE refers to volumetric efficiency, or the %'age of the cylinder that you can fill with fresh charge. For a 2ltr, thats 500cc per cylinder. If you can only fill that cylinder with 430cc's at peak efficiency (normally at peak torque point) thats 86% VE. The higher the VE on any engine, the higher the torque output at that specific RPM, and all engine tuning revolves around increasing or rather sustaining a good VE for as long as possible, and upto as high an rpm as possible.

Anyway, back on track. The clio with its advanced cam timing (phased) operates with an overlap value that is larger than when it is dephased (infact it has no overlap when depahsed). This overlap is part of cam design basics, and larger overlap periods are used to help generate higher VE's via scavenging and inertia ramming. At 5000 rpm the natural effects of the port velocity and pulse tuning al reach a level where they start to actively enhance the torque production with the valve timing it is running. Put in a wilder cam and it will push the 'kick' higher up if nothing else changes, but lower rpm efficiency will loose out, and peak power will be pushed up the rpm scale, along with a higher peak bhp figure. To an extent, there will be a point where you can go wilder on the cam and just loose out everywhere as the engine system as a whole does not work with the cam profile you are running.

Not very clear sorry, basis is that the 5k kick is the result of natural phenomenons within the engine, primarily port velocities and pulse tuning harmonics.

 

[Bash]

Thanks for that Day, awesome read do u have a link to that quote?

 

[Day]

BenR posted it some time ago, thought I'd save him writing an epic every time this question is raised...

 

[Liam]

yeah need pics. Them spark plugs seem cheap too, and thats wrong oil isnt it?

 

[davebem]

Id check those spark plugs, they should be NGK Platinum PFR6E-10 and nothing else, as Fred says they are £12-13 each. It could have had the incorrect plugs to start off with and this could be whats causing the issue?

As for the mechanic/engine, the big giveaway is RenaultSport lettering written across the top of the inlet manifold which indicates its a F4R with vvt.

 

[Fred@BTM]

wrong spark plugs mate! they're £13 EACH!!!
wrong oil too, its a 5W40, 30 is incorrect

i bet the timing is out or your have a sensor fault

keep up chaps, i've said that already

 

[JMR]

My cam belt has just been replaced at GDI. Now the timing is c0ck on [on 60k miles now] there seems a very healthy increase in acceleration

It was fast enough before, but since aux/cambelt/service and the Silkolene ProS oil change it seems like a different car!

......reg plate is the same, not checked the VIN number though...:clown:

 

[Fred@BTM]

As for the mechanic/engine, the big giveaway is RenaultSport lettering written across the top of the inlet manifold which indicates its a F4R with vvt.

that bolts straight onto a normal F4R

 

[Keydogg]

Right - Just to clear things up - I'm 99.99999999999999999% sure its a true 172 engine for the following reasons:

The car has every characteristic of a 172 such as: Xenons, interior, climate control, it revs to 6700ish when cold and 7200ish when warm, the brakes are massive, the ride height is correct for a 172 etc

The enging rocker says 2.0l 16v and it says renault sport and the engine is fookin massive for such a small engine bay as 172s are.

About the spark plugs - Im furious tbh, he told me they were the correct ones. Would this make that much difference?

As far as oil is concerned, it being 5w30 and not 5w40 will make naff all difference to the performance we all know that!

The mechanic did put it on his diagnostics and saihe sensors etc are all fine.

I wish there was a cheap way of doing this, it seems that I'm having to spend a lot of money to get the car as it should be from standard! Im skint with christmas coming up so i dont have the money for a rolling road or anything

 

[lemonnobby]

Pictures of the engine, people can only replace the engine you know not, it may have started out as a 172 but had an engine replacement???? and it was cheaper to get a 2.0 the inlet bolts straight on as fred says. and so would every thing else only thing different would be the loom but you could just use the normal 172 one anyway

 

[Fred@BTM]

About the spark plugs - Im furious tbh, he told me they were the correct ones. Would this make that much difference?

As far as oil is concerned, it being 5w30 and not 5w40 will make naff all difference to the performance we all know that!

spark plugs make a MASSIVE difference you paid £12 for 4, the correct ones are £13 EACH, you figure it out

and you're wrong about the oil, thats too thin for your engine, you want to leave it in their then go for it, just don't come on here moaning your engine is fucked

next time take it to a specialist

 

[Keydogg]

About the spark plugs - Im furious tbh, he told me they were the correct ones. Would this make that much difference?

As far as oil is concerned, it being 5w30 and not 5w40 will make naff all difference to the performance we all know that!

spark plugs make a MASSIVE difference you paid £12 for 4, the correct ones are £13 EACH, you figure it out

and you're wrong about the oil, thats too thin for your engine, you want to leave it in their then go for it, just don't come on here moaning your engine is f**ked

next time take it to a specialist

Hehe well thanks for the advice anyway! Well I'm gonna take it to my mates as he has a 172 and i know for a fact he has the correct sparks, so I'm gonna swap them over and see if a difference is made.

If not then

 

[mattjk]

isnt the only difference between 30 - 40 is that 30 will be slightly thinner when cold? I dont know this for sure but cant see a big difference

 

[Andy GDI]

5w40 is the correct grade of oil for the clio engine

we use 15w50 in our race and track engines.... as it is better at higher temps... but its not as good at cold protection... so you have to "properally" warm the engine up

 

[Fred@BTM]

isnt the only difference between 30 - 40 is that 30 will be slightly thinner when cold? I dont know this for sure but cant see a big difference

thinner at 100degC not a good idea!

 

[Fred@BTM]

15W50 is fine down to -10degC from memory, so unless you're racing in the arctic circle i can't see cold protection being a problem

 

[davebem]

Spark plugs are very important, the correct ones have the gaps preset for the 172/182. They should be as below but dont bother getting them from renault, you can buy the 4 set cheaper elsewhere on the internet.

 

[franx]

get your IK manifold matched ; maybe a terrible one from factory !?

 

[oldboy]

get your IK manifold matched ; maybe a terrible one from factory !?

.......wots an IK manifold?

 

[Andy GDI]

as long as you use the correct heat grade, i.e. nkg grade 6 they will be fine... the platinum bit only helps the plugs last longer...

for mild tuned engines we use BKR7EIX plugs...

for higher revving and hard working engines we use BCR8ES (same as used in cossie engines)

without the correct heat grade when mapping there is a serious risk of turning the plug into a plasma torch.... you end up chasing the timing back as the plug cant take the heat.... we have done alot of testing on this on the rollers....

on std or mild modded engines the std PFR6.... is fine..

 

[D1CKY]

Sorry to Gatecrash this post.

I thought the 172/182 would have triple fire plugs ?:S

Would the standard plugs that came with my car ,be ok for my car mate ?

With the mods i have ?


I have a full stainless stealth system with de-cat and uprated panel filter with no acoustic valve and uprated feed.

Or when would i have to change spark plugs types ?

If i got a Remap and matched inlets or would it be when i get more mods down line ?

Like cams etc etc.

 

[Fred@BTM]

as long as you use the correct heat grade, i.e. nkg grade 6 they will be fine... the platinum bit only helps the plugs last longer...

for mild tuned engines we use BKR7EIX plugs...

for higher revving and hard working engines we use BCR8ES (same as used in cossie engines)

without the correct heat grade when mapping there is a serious risk of turning the plug into a plasma torch.... you end up chasing the timing back as the plug cant take the heat.... we have done alot of testing on this on the rollers....

on std or mild modded engines the std PFR6.... is fine..

disagree with you massively there Andy

 

[D1CKY]

as long as you use the correct heat grade, i.e. nkg grade 6 they will be fine... the platinum bit only helps the plugs last longer...

for mild tuned engines we use BKR7EIX plugs...

for higher revving and hard working engines we use BCR8ES (same as used in cossie engines)

without the correct heat grade when mapping there is a serious risk of turning the plug into a plasma torch.... you end up chasing the timing back as the plug cant take the heat.... we have done alot of testing on this on the rollers....

on std or mild modded engines the std PFR6.... is fine..

disagree with you massively there Andy

How come Fred ? ?