How Much Of A Difference Higher Lift Makes ? + Camshaft Duration

[cobrAA]

Good evening gentleman !

1) I spoke with my engine builder yesterday and he told that the higher lift camshaft is slightly over-rated. He told me I should see a gain of about 10-15whp by going to a 10.25mm Vs. 9.15mm. If thats the case, I don't see all the fuzz about high +10mm lift which result in high cost to fit/shim and more wear on the head for so little gain.

2) For those who don't know, I'm going for an EFR 83/74 1.05, would a 250-256 duration work with that combo or the powerband will go down too quickly in the 6.5k rpm ?

Right now, i have TYpe-B.. I was thinking going PROCAM with 260 and 10.25mm lift, but I don't think it's worth it for a slight gain of 15whp ( when you are already making 650whp) and higher wear on the valvetrain.

I looked at camshaft and I came up with a few choices :

Mine's : 252 with a 10.05mm ( but they are 1600..)
HKS: 256 8.7mm OR 264 with 10mm
Tomei : Procam ( 252 with 9.15mm, the most similar setup to the mine's) OR 260 10.25 procam
Jun: 256 with 9.7mm OR 248 with 9.15mm OR 264 with 10.5mm
Kelford: offer custom cam for 900$usd ( I could ask them for a copy of the mine's for twice cheaper) OR 264 with 9.2mm
Brian crower and camtech doesn't offer anything new the others don't already.

As you can see, I did my research, but looking for other output than simply the one from my engine builder. Forums are great for that

Cheers!

[Ben C34]

Have you considered what the extra lift will do to the engines midrange etc? It's not all about peak power.

Sounds like your engine builder is special...

[cobrAA]

Have you considered what the extra lift will do to the engines midrange etc? It's not all about peak power.

Sounds like your engine builder is special...

Well.. he like to cut the bs and cut in stuff that is not really worth it ( but worth it to his point of view) hence why im looking for other point of view lol.

[Lithium]

I think too many people who know way too little about engine design/performance over think things, when there are lots of aftermarket outfits who know exactly what they are doing and have done the R&D for you. What is the rest of the setup? What fuel will you be running?

Is there any reason you'd go the custom Kelford and not an off the shelf one? Kelford tend to do some of the best performing cams out there - if I had a similar build to what it sounds like you are doing, this would probably be my choice:

http://www.camshaftshop.com/products.php?productid=1021#specs

[r32-25t]

I've seen 3 cars with the same turbos all tuned on the same fuel

The ones with the poncams made <450kw

The one with the 260 with 10.8 made 475kw

You do that math

[GTSBoy]

The point here cobrAA is that you wasted money when you bought the Type Bs. If you had avoided that mistake the first time and spent the money on cams with better lift then you wouldn't be worrying about the perceived lack of incremental benefit from fitting the better cams. If the cams were already in the engine when you bought it, then don't think about the perceived lack of incremental benefit. Either piss, or get off the pot.

[cobrAA]

True the poncam Type-B came with my engine.

I don't think anything over 260 will do me any good since I'm also caring for clean idle and good response low-mid.

I already ordered the full Supertech overhaul head kit, all I'm missing is the cam ( or keep mine). I also care for ''reliability'' ( if i'm allowed to use that term with my build lol..). So, if the general concensus is that anything higher than 10.3mm will prematuraly wear my valvetrain, I will stay max 10.3mm.

[cobrAA]

The point here cobrAA is that you wasted money when you bought the Type Bs. If you had avoided that mistake the first time and spent the money on cams with better lift then you wouldn't be worrying about the perceived lack of incremental benefit from fitting the better cams. If the cams were already in the engine when you bought it, then don't think about the perceived lack of incremental benefit. Either piss, or get off the pot.

I don't mind selling my poncam type-b and ordering new one..Seems like the type-R are under-looked and actually a better set than the B.

[Sinista32]

The Type R's appear to be hard to get at the moment.

Mine took 6-8 weeks very recently through RHD. (yet to be installed).

I believe it may take even longer than that and I was a little lucky.

My first build the Type B's were recommended and installed.

Different goals in mind with the thought of larger turbo's etc...

and not being any wiser a decade ago didn't help at all

[Lithium]

I don't think anything over 260 will do me any good since I'm also caring for clean idle and good response low-mid.

I already ordered the full Supertech overhaul head kit, all I'm missing is the cam ( or keep mine). I also care for ''reliability'' ( if i'm allowed to use that term with my build lol..). So, if the general concensus is that anything higher than 10.3mm will prematuraly wear my valvetrain, I will stay max 10.3mm.

Did you check the link I provided? The 272/10.0s are within the lift range that you mentioned, and to quote Kelford:

"272 Duration, 10.00mm/9.95mm Lift. High performance cams to suit applications where low end power and fast spool up is important"

The idle will no doubt be not stock, but I doubt they would have said "low end power and fast spool" for a product that is biased to drag-type behaviour. You are not so likely to get a night and day change with a minimal upgrade in aggressiveness as well, this is more likely to turn the car into a new kind of beast - as I suggested earlier, it's at least what I'd personally do if I was putting an EFR8374 on my RB26... and I wouldn't be going for an EFR8374 aiming for a laggy peaky setup.

[XKLABA]

I know when I changed from 260 Poncams to 250 poncams with no other change, so same lift with less duration I had the same peak power but every thing happened +/-800-1000rpm sooner in the rev range, but that was just what I experienced but since I don't grind cams for a living what would I know

[djr81]

The Type R's appear to be hard to get at the moment.

Mine took 6-8 weeks very recently through RHD. (yet to be installed).

I believe it may take even longer than that and I was a little lucky.

My first build the Type B's were recommended and installed.

Different goals in mind with the thought of larger turbo's etc...

and not being any wiser a decade ago didn't help at all

You can ask Tomei to grind a number of different durations. Poncam inlets are 260's and either 252 or 260 exhaust. But you can get 256 durations, for example, just had to ask. Not 100% sure they are still available.

Did you check the link I provided? The 272/10.0s are within the lift range that you mentioned, and to quote Kelford:

"272 Duration, 10.00mm/9.95mm Lift. High performance cams to suit applications where low end power and fast spool up is important"

The idle will no doubt be not stock, but I doubt they would have said "low end power and fast spool" for a product that is biased to drag-type behaviour. You are not so likely to get a night and day change with a minimal upgrade in aggressiveness as well, this is more likely to turn the car into a new kind of beast - as I suggested earlier, it's at least what I'd personally do if I was putting an EFR8374 on my RB26... and I wouldn't be going for an EFR8374 aiming for a laggy peaky setup.

272 for low end power? An 260 degree Poncam is hopeless for low and cant imagine another 12 degrees, irrespective of lift, is going to help.

I know when I changed from 260 Poncams to 250 poncams with no other change, so same lift with less duration I had the same peak power but every thing happened +/-800-1000rpm sooner in the rev range, but that was just what I experienced but since I don't grind cams for a living what would I know

Surprised by this. 260's are laggy, 250's not so but I lost hp dropping the exhaust cam duration.

CAVEAT: Be very careful how much lift they are quoting for their durations. Eg Halfords is

Advertised Duration @

0.35mm

Intake:

272

Exhaust:

272

Duration @

1.00mm VALVE LIFT

Intake:

234

Exhaust:

234

Edited October 6, 2014 by djr81

[Lithium]

I know when I changed from 260 Poncams to 250 poncams with no other change, so same lift with less duration I had the same peak power but every thing happened +/-800-1000rpm sooner in the rev range, but that was just what I experienced but since I don't grind cams for a living what would I know

Argh this reminded me of a post I made last week, apologies if I've been a bit bad behaved in posts - especially last week, was (well am) burning the candle at both ends trying to get ready for the trip to Oz and hadn't realised until too late that I'd started being more flamin mongrely than usual with online posts.... if you're anything like me you probably don't take it personally, but nonetheless I felt like a twat after I'd had a bit of actual sleep. My bad! I did have a point I was making (the picture is much bigger than it seems like you and others are considering) I stand by, but the delivery etc was poor form.

Anyway yeah, I remember you mentioning that before - clearly a good result, and proves a general rule of thumb and actually quite surprising, I obviously can't debate it but not sure I'd set that as an expectation for everyone. Do you have the dyno comparison? And is that the same lift, etc etc?

272 for low end power? An 260 degree Poncam is hopeless for low and cant imagine another 12 degrees, irrespective of lift, is going to help.

CAVEAT: Be very careful how much lift they are quoting for their durations. Eg Halfords is

That's what Kelford advertise, yes. Do you reckon they are lying, or wrong? What I am guessing from what they suggest in that blurb is aside from being a cammy at low rpm it's likely to have a hell of a power delivery. I haven't tried that exact cam profile so am not going to state exactly what it will perform like as fact, but on the flipside I have been involved with a few cars using Kelford cams and know that they probably know a lot more about cam design than I, and probably everyone in here, I know that their cams have always done exactly what they said they would in the cases I have been exposed to, and they tend to perform a lot better than equivalents from other brands I've seen mentioned here in cases I've seen where people have upgraded to them. I'd venture to say that comparing advertised duration and lift between Kelfords and Tomeis to guess power & delivery would be like comparing compressor sizes between Precision Gen2 CEA turbos and Turbonetics T-series to determine the same.

When you said Halford - were you talking about Kelfords? Either way, totally agree with the caveat. Goes beyond that too, the opening/closing of valves and some stuff you probably can't tell from specs will have an influence on the performance and at the end of the day unless you have some serious experience or at least theory with engine / cam design it's probably a lot safer to take into account the manufacturers description and advice on the different models to set expectations instead of casual glances at advertised lift and duration to pigeon hole cams of completely different brands and designs together... which is a lot of why I piped up in this thread.

I'm no expert in this, but I know enough to know I don't know enough to tell people how cams I've not experienced first hand are going to perform with any kind of confidence from those two numbers - I suspect most others are no more qualified, if not less to make that call. I don't mean that to be rude, I'm just pointing out that it's probably something better to go more by peoples results... ideally with the same kinds of setup overall as you are going to be using, that's probably the best way to go about choosing cams.

Just my thoughts, anyway. I should highlight the "I'm no expert" of course, if there is one in here - this would be a great place to add more if they were so kind

[XKLABA]

Argh this reminded me of a post I made last week, apologies if I've been a bit bad behaved in posts - especially last week, was (well am) burning the candle at both ends trying to get ready for the trip to Oz and hadn't realised until too late that I'd started being more flamin mongrely than usual with online posts.... if you're anything like me you probably don't take it personally, but nonetheless I felt like a twat after I'd had a bit of actual sleep. My bad! I did have a point I was making (the picture is much bigger than it seems like you and others are considering) I stand by, but the delivery etc was poor form.

Anyway yeah, I remember you mentioning that before - clearly a good result, and proves a general rule of thumb and actually quite surprising, I obviously can't debate it but not sure I'd set that as an expectation for everyone. Do you have the dyno comparison? And is that the same lift, etc etc?

My result was no accident, I know exactly what I was doing and why I was doing it and I got the result I expected, I can explain the theory as to why but to be honest CBF typing it out, if we get to catch up again at WTAC I will explain my theory to you if you like

Both cams where Poncams, 9.15mm lift, just one was 250 and the other was 260, both sets of cams where dialed in the give the best response they could, the 250s where just better

I'm not one for dyno graphs, I got one when I first got the car dynoed with this setup so I knew the power band but I had it tuned two weeks ago for the trackday and don't even know what power it made , all I asked my tuner was how is it running, his answer "strong", that'll do me

[Lithium]

My result was no accident, I know exactly what I was doing and why I was doing it and I got the result I expected, I can explain the theory as to why but to be honest CBF typing it out, if we get to catch up again at WTAC I will explain my theory to you if you like

Both cams where Poncams, 9.15mm lift, just one was 250 and the other was 260, both sets of cams where dialed in the give the best response they could, the 250s where just better

I'm not one for dyno graphs, I got one when I first got the car dynoed with this setup so I knew the power band but I had it tuned two weeks ago for the trackday and don't even know what power it made , all I asked my tuner was how is it running, his answer "strong", that'll do me

OK sweet. Yeah I will be catching up with Mick on Saturday coming, and will be at WTAC for sure so be good to shoot the shxt again. I remember (roughly because it was one convo almost a year ago- can't remember the details) that it turned out there was stuff that had been not considered when you made the decision for the cams though obviously a lot of theory was solid, sometimes expected outcome can be part luck and part design and the proof can be misleading. I know this, as I've been sent down the wrong path when I have been "proven" right haha - not saying you chose wrong at all as that'd be folly, just saying keep an open mind as one expected result doesn't necessarily mean it's all nailed down.

Be very good to chat further on this, its good having people on the same wavelength with different parts of the puzzle

[jet_r31]

I know when I changed from 260 Poncams to 250 poncams with no other change, so same lift with less duration I had the same peak power but every thing happened +/-800-1000rpm sooner in the rev range, but that was just what I experienced but since I don't grind cams for a living what would I know

sounds like you car was restricted by turbine/exhaust flow and the camshaft had to much duration and coudn't rev to where it was designed to

as it was choked by turbine backpressure, so you effictively shortened your powerband

Correct camshaft had less duration, so spooled faster, opened up powerband and nosed over at same rpm as it reached it proper rev range

cheers

darren

Edited October 6, 2014 by jet_r31

[XKLABA]

-7s on modified stock manifolds, CES comp series split dumps with matching front pipe to a 80mm HKS cat and 80mm exhaust, no restrictions in it at all, I looked several times lol

I only restriction in the exhaust was the turbos

Edit: that setup didn't nose over, held all the way to 8k

[Lithium]

Yesssss

-7s and a 1.05a/r EFR8374 are quite different beasts... I wouldn't suggest the cams I suggested for the EFR for a -7s setup, and vice versa.

Xkalaba - I love dyno results haha. I am a data fiend, though that's because with more data you can get closer to determining what is going on and which bits are and aren't cooperating. Don't confuse it with being tied up with dynos being the be all and end all at all, they are just another data source... but a very useful one in he right situation

[XKLABA]

Oh I agree, and I always get one if I make a decant size change, I just generally don't keep em once I've looked at them, the last dyno was due to change of alternator (180amp) and pump and coil rewire to supply power directly from alt, and oil breather catch can setup so power band wouldn't have changed so I figured a graph this time was not neccasary

[cobrAA]

The Type R's appear to be hard to get at the moment.

Mine took 6-8 weeks very recently through RHD. (yet to be installed).

I believe it may take even longer than that and I was a little lucky.

My first build the Type B's were recommended and installed.

Different goals in mind with the thought of larger turbo's etc...

and not being any wiser a decade ago didn't help at all

I'm buildin the engine in 4 month so i can wait

Did you check the link I provided? The 272/10.0s are within the lift range that you mentioned, and to quote Kelford:

"272 Duration, 10.00mm/9.95mm Lift. High performance cams to suit applications where low end power and fast spool up is important"

The idle will no doubt be not stock, but I doubt they would have said "low end power and fast spool" for a product that is biased to drag-type behaviour. You are not so likely to get a night and day change with a minimal upgrade in aggressiveness as well, this is more likely to turn the car into a new kind of beast - as I suggested earlier, it's at least what I'd personally do if I was putting an EFR8374 on my RB26... and I wouldn't be going for an EFR8374 aiming for a laggy peaky setup.

I did check kelford already mate, you agree the type-B are not the best cam out there ? Tomei also say it will provide good responce and low-end same as Kelford. so why would I trust kelford's marketing more than tomei ? I'm doubting a 272 degree camshaft can be classified as low end power.

Like you said, I'm no expert, but I think the general concensus is that the higher the duration is, the power range move to the left and idle is lumpier. ( 2 things I don't want).

Argh this reminded me of a post I made last week, apologies if I've been a bit bad behaved in posts - especially last week, was (well am) burning the candle at both ends trying to get ready for the trip to Oz and hadn't realised until too late that I'd started being more flamin mongrely than usual with online posts.... if you're anything like me you probably don't take it personally, but nonetheless I felt like a twat after I'd had a bit of actual sleep. My bad! I did have a point I was making (the picture is much bigger than it seems like you and others are considering) I stand by, but the delivery etc was poor form.

Anyway yeah, I remember you mentioning that before - clearly a good result, and proves a general rule of thumb and actually quite surprising, I obviously can't debate it but not sure I'd set that as an expectation for everyone. Do you have the dyno comparison? And is that the same lift, etc etc?

That's what Kelford advertise, yes. Do you reckon they are lying, or wrong? What I am guessing from what they suggest in that blurb is aside from being a cammy at low rpm it's likely to have a hell of a power delivery. I haven't tried that exact cam profile so am not going to state exactly what it will perform like as fact, but on the flipside I have been involved with a few cars using Kelford cams and know that they probably know a lot more about cam design than I, and probably everyone in here, I know that their cams have always done exactly what they said they would in the cases I have been exposed to, and they tend to perform a lot better than equivalents from other brands I've seen mentioned here in cases I've seen where people have upgraded to them. I'd venture to say that comparing advertised duration and lift between Kelfords and Tomeis to guess power & delivery would be like comparing compressor sizes between Precision Gen2 CEA turbos and Turbonetics T-series to determine the same.

When you said Halford - were you talking about Kelfords? Either way, totally agree with the caveat. Goes beyond that too, the opening/closing of valves and some stuff you probably can't tell from specs will have an influence on the performance and at the end of the day unless you have some serious experience or at least theory with engine / cam design it's probably a lot safer to take into account the manufacturers description and advice on the different models to set expectations instead of casual glances at advertised lift and duration to pigeon hole cams of completely different brands and designs together... which is a lot of why I piped up in this thread.

I'm no expert in this, but I know enough to know I don't know enough to tell people how cams I've not experienced first hand are going to perform with any kind of confidence from those two numbers - I suspect most others are no more qualified, if not less to make that call. I don't mean that to be rude, I'm just pointing out that it's probably something better to go more by peoples results... ideally with the same kinds of setup overall as you are going to be using, that's probably the best way to go about choosing cams.

Just my thoughts, anyway. I should highlight the "I'm no expert" of course, if there is one in here - this would be a great place to add more if they were so kind

Hence why I wanted to open this discussion so hopefully some peoples can shed some light on these.

Yesssss

-7s and a 1.05a/r EFR8374 are quite different beasts... I wouldn't suggest the cams I suggested for the EFR for a -7s setup, and vice versa.

Xkalaba - I love dyno results haha. I am a data fiend, though that's because with more data you can get closer to determining what is going on and which bits are and aren't cooperating. Don't confuse it with being tied up with dynos being the be all and end all at all, they are just another data source... but a very useful one in he right situation

If type-R works well with -7s. maybe the Type-B are actually a good match to the higher flowing turbo I have.. I don't know, maybe the Type-R can make the 83/74 spool even quicker too..