F4R Cams Vs F4RT Cams [Archive]

SP33DY

31-01-2010, 17:23

Right as some know I have a clio 182 turbo I'm currently in the process of redoing the turbo conversion and am curious about camshaft choices.

We already know that the stock F4R (clio 172's) will allow enough airflow for 400+ as this has been proven (by Scoff) but I'm curious to know what if any gains the dedicated turbo cams in the F4RT (meg 225/230) will give.

I know the F4R cams are 269 inlet and 256 exhaust but I can't find any info at all on the F4RT cams. I'm wondering if the milder F4RT cams would be more suited to road applications?

I've had a look at power graphs to see roughly how much boost you need to get to hit 300bhp and it would appear to be the same for both setup's but the mid range torque for the F4RT seems alot higher.

Obviously there are a few differences between a my turbo F4R engine and a F4RT engine.

Inlet manifold design and throttle body size.
C/R 8.5 vs 9.5
Tdo4 turbo vs gt28r

So what do people think, is it a pointless exercise? or if I can get a set cheap enough is it worth a punt?

Cheers

Steve

Scoff

31-01-2010, 17:56

Here's the thing though - the amount of boost you need to make xyz bhp will change a lot when you consider different turbo types, intercooling and so on. I was able to make about 300hp @ 15psi with my 1800cc f4r, 320hp @ 17psi. I think the f4rt with it's road-turbo cams would struggle to do that, and definately wouldn't make anywhere near 300hp on a standard 225 type turbo at only 15psi.

Every fibre in me says not to fit the f4rt cams, unless you really need a perky engine aimed at the road, or you have no option but to use the standard turbo. The f4r cams will win hands down on the track and strip if coupled with a 28rs or something of that size. If you have no option but to stick with the original turbo then actually the f4r cams may be a hinderance. certainly you would not want the VVT engaged at any time. For me atleast the f4r cams locked @ idle timing (no inlet cam advance) has worked really well and made a nice torque curve that was still very very usable on the road if coupled to a moderate turbo.

Scoff

31-01-2010, 18:01

Further to the VVT thing, if I had mapped the VVT in I could have had a nice mid-range boost by switching it on. The VVT really helps at around 2500rpm - 3500rpm, however it was a hinderence once boost came on strong so I would have needed to switch the VVT in, then out again once boost came up. That wasnt a problem technically, but since it wasn't going to make me go any quicker on the strip I didn't bother. For a road or track car I certainly would have.

SP33DY

31-01-2010, 18:10

Cheers Chris, I've just been looking at different megane 225 power graphs and they do seem to ramp up loads on the torque front, which could cause problems with the stock jc5 gearbox.

But i'm not sure how much of this is down to the cams alone. Obviously the megane 225 has a smaller turbo as well as the smaller throttle body.

Where this all stemmed from is I've been looking at various other 2.0 tubo lumps and found most have fast road cams available for them usually in the 265/265 duration area. This got me thinking that maybe the meg cams might be a little bit milder but better suited to forced induction.

I also considered fitting a cat cam 421 exhaust cam which would give me 269/269 but wasn't sure if that would make it to extreme. It would certainly give me problems in the overlap area as with out adjustable cam pulleys I'd only be able reduce the overlap to about 14 degrees.

Matt Cole

31-01-2010, 18:17

Yes the 225 is pretty much torque front loaded but i think some of this stems from the twin scroll turbo set up as well as the zippy turbo the td04 is. Imo i could spread that torque curve with a bigger turbo at moderate boost. This might take some of the 'lethargic' feel at higher rpm as the torque drops off. As has been said though running big boost might not suit the cams. I suppose i'll just have to try it and see.:agree:

Scoff

31-01-2010, 18:23

The 225's turque curve will have nothing to do with it's throttle. the size of throttle is chosen with an amount of power in mind, so should not be a limiting factor. It might be a slight factor when shooting for 300hp though but still it should not be small enough to cause real problems. (I'm assuming they're 45mm ?)

The lumpy curve is to do with 3 things: tiny turbo, mild cams and poor boost control.

Also, there isnt much point in comparing lobe durations between different manufacturers. often they're measured in a different way (IE, they could measure duration from the moment the valve starts to lift, or from 0.1mm of lift, or from the cam so as not to take into account valve lash etc). So don't read into the numbers too much unless you have the other data to compliment them.

Not sure what you were getting at with reference to the 421 exhaust cam. did you mean to pair it with a f4rt inlet ? If anything it'll be a wilder inlet you want and then maybe play with it's timing until overlap is no longer a problem. Just fitting the f4rt exhaust cam might be a compromise for you.

Scoff

31-01-2010, 18:26

Having said all of that though, if you're still planning on getting that 0.82ar turbine on I'd leave well alone, stick with the f4r cams and maybe consider shutting the VVT off as boost gets up.

SP33DY

31-01-2010, 18:36

I compared the catcams inlet from the group n cams and the exhaust from the 421

http://www.catcams.co.uk/cgi-bin/sh000001.pl?REFPAGE=http%3a%2f%2fwww.catcams.co.uk %2f&WD=clio&PN=Renault_clio_rs.html%23a100#a100

I'm surprised that your advising a wilder inlet (but your leaading the way with turbo F4R so I'm not argueing :)) as practically everything I've read on turbo camshafts says that the inlet doesn't need to be as wild or have a high lift due to the positive pressure in the intake (as appose to sucking it in N/A style) and that it's getting the exhaust gases out that becomes the harder part. Other such things I've read are for tubular manifold setups like for like inlet/exhaust cams should be used and when using a log manifold have the exhaust cams 6 dgrees less than the inlet to account for the back pressure in the manifold.

There is talk of meganes running 400bhp in europe on stock cams and I know Paul at RS tuning is running 325 with his at the moment.

Scoff

31-01-2010, 18:51

Oh for sure, I wasn't saying you couldn't make more than 300hp with those fr4t cams, just that it gets harder.

As for fitting something wilder in the inlet, it's not new, the c20let turbo guys have been doing it for years, fitting XE inlets (from the normally aspirated version of the same engine) and adjusting the timing to suite.

As for the talk about manifolds, take that with a pinch of salt. the turbo bolted to the end of the manifold is of much greater consiquence. Regards the inlet not being as important because we have boost, it doesn't hold water for me. Thats saying it's ok to wind the boost up instead, to counteract a poor cam. Well it works, to a point, but it's the wrong way to tune. That "point" will come when suddenly you can't make any more power no matter how much boost you run. Better to improve v.e and not have to use all that boost. Then if you decide you want to make more power you still have scope to increase the boost.

SP33DY

31-01-2010, 18:55

It really is a shame that no one sems to know what the F4RT cam specs are, you never know they might just be the same spec as the F4R and I'm just talking about thrownig away a load of cash for no reason LOL

Scoff

31-01-2010, 18:58

Definately not the same. For one, they idle without needing all that inlet retard (as per the 172). I've mapped one too, so I was able to see and feel the torque curve. They're much milder for sure.

Andrew Cooke

31-01-2010, 19:01

if someone has some F4R cams lying around I could look at making a rig for checking profiles. I'm done with measuring C1J cams :laugh:

Scoff

31-01-2010, 19:04

if someone has some F4R cams lying around I could look at making a rig for checking profiles. I'm done with measuring C1J cams :laugh:

I do, if you really fancy it ?

Andrew Cooke

31-01-2010, 19:07

I do, if you really fancy it ?

yeah, sure. I'll be measuring cam profiles not valve lifts, but I think this time I'll reference to the design TDC position. I need to make a few bits , so not sure how long it'll take me.

SP33DY

31-01-2010, 19:11

I wonder if I can sneak Andys F4RT cams down to you before he puts them in his new engine?

Scoff

31-01-2010, 19:15

yeah, sure. I'll be measuring cam profiles not valve lifts, but I think this time I'll reference to the design TDC position. I need to make a few bits , so not sure how long it'll take me.

Do you want me to post them to your home addy, or work ? If work you'll need to pm me the address.

Andrew Cooke

31-01-2010, 19:15

I wonder if I can sneak Andys F4RT cams down to you before he puts them in his new engine?

it would be great if you could, but I'm not sure how long it would take me to knock up a rig, it was easy with the C1J as I just used a spare engine block to hold everything in the right place.

in a similar vein, once I'm up and running I'll gladly measure any f4r cam that comes my way :)

Andrew Cooke

31-01-2010, 19:16

Do you want me to post them to your home addy, or work ? If work you'll need to pm me the address.

work is best, they haven't made me redundant yet and there is always someone available to take a delivery :)

Scoff

31-01-2010, 19:18

I feel a "cam wizard - f4r edition" might be in order :)

Andrew Cooke

31-01-2010, 19:21

I feel a "cam wizard - f4r edition" might be in order :)

fo sho :agree:

Best get myself rooting around in the scrap bins at work for inspiration :D

SP33DY

31-01-2010, 19:22

I'm sure if we can persuade Andy that its for the good of the RTOC comunity he might.

Mind you when I dropped his turbo off earlier he was like a kid at xmas and is talking about getting the engine in next week, so I'd imagine Scoff will be getting a call about an adaptronics unit soon.

Scoff

31-01-2010, 19:23

Best get myself rooting around in the scrap bins at work for inspiration :D

If you have any left over, send it my way. That and some motivation, if you come across a pile of it. :crap::)

Andrew Cooke

31-01-2010, 19:24

I feel a "cam wizard - f4r edition" might be in order :)

for the C1J in case anyone was wondering...
http://www.rtoc.org/cam/

Rob@Backyardracing

31-01-2010, 19:30

If you have any left over, send it my way. That and some motivation, if you come across a pile of it. :crap::)

:laugh:

Andrew Cooke

31-01-2010, 19:34

If you have any left over, send it my way. That and some motivation, if you come across a pile of it. :crap::)

unfortunately the factory is very efficient, it sucks the motivation out of everything leaving only washed up scrap :cry:

MFaulks

31-01-2010, 21:36

Andrew Cooke

02-02-2010, 23:53

I can help you guys out here if you want, I have a digitised setup for lift and duration straight into the PC and can dump to Excel etc - see the Clee's GTA thread for pic. Can do it off the lobe resolved to 3600 points / 360 deg or off the valve with weak springs which is my preffered method, as I always want to know exactly valve lift for comparing with flow data etc.

So if that will help you, happy to do it, just let me know. I've got cams to measure at the moment, so sooner is better for me, as I will be using my mill for other things soon, and it's sat on my milling table.

good offer there :agree:

looking at the rocker arrangement on the clio I think I'd rather modify a scrap head so the the valve action is plotted. I can't see how else to measure the designed timing and overlap. So if anyone has a scrap head kicking around as well as enough valves etc to assemble 1 cylinder....

Scoff

03-02-2010, 00:19

I sent the cams on monday andy. I have some spare cyl heads too, although not scrap you could have loaned one for the testing. Bit of an ar$e to post though :)

Andrew Cooke

03-02-2010, 00:31

I sent the cams on monday andy. I have some spare cyl heads too, although not scrap you could have loaned one for the testing. Bit of an ar$e to post though :)

cheers Chris, I'll keep my eyes open for them :)

I think it'd need to be a scrap head as I'd probably need to cut up the cam cover to give access to the lifters - they need to be solid adjustables to set the geometry. I've been through that faff with the Evo cams...

SP33DY

03-02-2010, 09:31

I have a scrap hear thats in the care of Andyrg it was on the engine block that were using for the f4r/f4rt hybrid engine. I'm going through tonight to help him with a few bits and bobs and to time the engine up so will grab it while I'm there.

I'll then brace my self for an Ass raping by the postage company! :)

Andrew Cooke

03-02-2010, 13:28

MFaulks

03-02-2010, 20:47

good offer there :agree:

Andy, no problem, offer is there mate.

If you can assemble cam, lifters and valves (I have test springs here) then if you want to come over here (I'm about 15mins from M40/M25 junction Chalfont St. Peter, so not a million miles from you), can map the cam in a few minutes. Capture the lift duration, phasing etc. Pull pretty much any data you need from the software. Takes longer to get into my garage than it does to do. I gave up doing it with dividing heads and dial gauges, just drove me nuts. Have a digital LVDT and an encoder on the back of the dividing head, software does all the work and calculates the overlap, TDC and a host of other stuff. Drop me a pm if you want to arrange if it helps.