Another camshaft question

Hi guys finally beginning to get on top of my engine swap etc but I am 100% sure I want to change the cams so my two choices are either kent , kelford or piper all of them claim to deliver the power in a range I deem acceptable my question is are any of them better built than the others or run better etc I'm really stuck in my choice was dead set on kent cams but I am tempted by the pipers now ! Any help would be greatly appreciated.
Thanks guys
Pete

What duration and lift you going for ?

11mm lift and 256 degree duration or around that area

This is not going to be much of a help but I've got those http://www.briancrower.com/makes/nissan/sr20det.shtml  stage 2 264 duration and 12mm lift apparently they'll fit standard springs... apparently because i still haven't fitted then

Piper 270 in mine (260 duration, 11.13mm lift) they are reprofiled standard cams.

The Kent is a bit milder and the kelfords are a bit more aggressive, really comes down to what matches your spec and goals.

I do however get some reversion at certain engine loads when gently coming off the throttle after building some boost such as during cruise conditions, part and parcel I guess.

I have HKS 264 cams in mine although I cant really comment on anything other than there in there. Hopefully see if there is any differences to the motor in the next month when it is on ze road

as said pete you know what I prefer

cams are dependant upon:
intended use of the car
engine build & components used
turbo sizing and other modifications
rpm limit and finally mapping and set up

best all round imho are the kent 258s then closely followed by hks 264s
both are proven to work nicely on your average power gtir.
if setup correctly and with a good ported head and free flowing ex system they give mid range a massive kick up the backside

seen some shocking ported heads over the years and if the works not done correctly youll end up down on power rather than see improvements, so no short cuts if you want to see the best results from them

My old engine had tomei 264's and I thought they were alright, I haven't really tried a large range of cams before though.

GTI-R US wrote:

cams are dependant upon:
intended use of the car
engine build & components used
turbo sizing and other modifications
rpm limit and finally mapping and set up

best all round imho are the kent 258s then closely followed by hks 264s
both are proven to work nicely on your average power gtir.
if setup correctly and with a good ported head and free flowing ex system they give mid range a massive kick up the backside

What do you consider average power?

I was all set to go standard until doing a bit of research. Im just assuming its the 260 pipers in mine (rather than the more aggresive 278) I think the cams are a good match for my spec but still thinking about something a bit milder to move the powerband down.

Kent does a 252, i think its kelford that do a 258.

the 260 pipers would be fine if you were running a smaller turbo but from memory with your car I believe your running a 3071r with larger 86 housing so although this tubby will make more topend power it is going to take longer to spool up.
Im not sure on the other aspects of your engine build with regard to comp ratio, valve cut, flow rate etc. related mods also play a part in deciding on cam choice to make the car as responsive as possible.

But without going into all the equasions and as a general rule of thumb decision I would look at it this way.
if your running a big turbo such as above or larger which is capable of 450+, have larger pistons fitted or running a thicker than stock head gasket to enable safer high boost levels then you will have a laggier car off boost so you want cams to kick in as soon as possible at low rpm which will aid off boost power.
once the turbo kicks in at lets say 4-4.5k then the cams are not really needed as the boost will create all the power you need.
so in light of that I would go for the lower duration but aggressive cam (but be careful with the lift) as that could cause you a problem if you have a high compression ratio and non valve relief type pistons fitted but on most you will be safe to run up to 12.5mm lift. ideally all this needs checking when engine is built as a dummy build will tell you what you can and cant get away with.
anything larger than hks 264s then would be advisable to fit uprated springs and retainers or you run a high risk of valve bounce.

the smaller the turbo the quicker it runs out of puff so to combat that you simply change gear and are using transmission ratios to slow engine speed which in turn creates boost again.
So baring that in mind then you could do with a larger duration less aggressive cam cam which will boost power and aid turbo when its heading toward its max flow rate or cfm.

theres much more to it than ive tried to described above but tried to keep it as simple as possible so you get the gist of it

I would of said exactly the same

GTI-R US wrote:the 260 pipers would be fine if you were running a smaller turbo but from memory with your car I believe your running a 3071r with larger 86 housing so although this tubby will make more topend power it is going to take longer to spool up.
Im not sure on the other aspects of your engine build with regard to comp ratio, valve cut, flow rate etc. related mods also play a part in deciding on cam choice to make the car as responsive as possible.

But without going into all the equasions and as a general rule of thumb decision I would look at it this way.
if your running a big turbo such as above or larger  which is capable of 450+, have larger pistons fitted or running a thicker than stock head gasket to enable safer high boost levels then you will have a laggier car off boost so you want cams to kick in as soon as possible at low rpm which will aid off boost power.
once the turbo kicks in at lets say 4-4.5k then the cams are not really needed as the boost will create all the power you need.
so in light of that I would go for the lower duration but aggressive cam (but be careful with the lift) as that could cause you a problem if you have a high compression ratio and non valve relief type pistons fitted but on most you will be safe to run up to 12.5mm lift. ideally all this needs checking when engine is built as a dummy build will tell you what you can and cant get away with.
anything larger than hks 264s then would be advisable to fit uprated springs and retainers or you run a high risk of valve bounce.

the smaller the turbo the quicker it runs out of puff so to combat that you simply change gear and are using transmission ratios to slow engine speed which in turn creates boost again.
So baring that in mind then you could do with a larger duration less aggressive cam cam which will boost power and aid turbo when its heading toward its max flow rate or cfm.

theres much more to it than ive tried to described above but tried to keep it as simple as possible so you get the gist of it

So what sort of cams would be good then, I'm running a 3071 and my mapper believes the engine was built with a lower compression, I'd like more kick before the turbo kicks in so what would be best?

GTI-R US wrote:

But without going into all the equasions and as a general rule of thumb decision I would look at it this way.
if your running a big turbo such as above or larger  which is capable of 450+, have larger pistons fitted or running a thicker than stock head gasket to enable safer high boost levels then you will have a laggier car off boost so you want cams to kick in as soon as possible at low rpm which will aid off boost power.
once the turbo kicks in at lets say 4-4.5k then the cams are not really needed as the boost will create all the power you need.
so in light of that I would go for the lower duration but aggressive cam (but be careful with the lift) as that could cause you a problem if you have a high compression ratio and non valve relief type pistons fitted but on most you will be safe to run up to 12.5mm lift. ideally all this needs checking when engine is built as a dummy build will tell you what you can and cant get away with.
anything larger than hks 264s then would be advisable to fit uprated springs and retainers or you run a high risk of valve bounce.

I'm still not sure if i have the .86 or .64 housing and I really would love to know.

Don't have a huge amount of time here as off to work but as I understand it for low down power the ideal scenario is more lift without increasing duration (there seems to come a stage where not enough duration high end will restrict power but that's another discussion), however with lift comes some duration, with that being said then surely an hks 264 will be similar to a 260 piper, although the hks do have more lift. (12mm as opposed to 11.13mm) which I imagine is why it makes good midrange.

The kent cams have a duration of 252 but lift is less than stock so surely there's not much low rpm benefit there? All they would do is replace lift with duration and move the powerband up a bit?

Maybe stock cams would be better for lowest rpm grunt but I wonder if they would restrict peak power significantly, not really a problem as I really do want to move it down a bit as I spend very little time at the top end.

I could be wide of the mark here however and of course there are a huge amount of other factors involved.

For reference other cam specs are

Piper - 260 duration 11.13mm lift
HKS - 264 duration 12.00mm lift
Kent - 252 duration 9.71mm lift
Kelford - 270 duration 11.71mm lift
Stock - 248 duration 10mm lift

So what sort of cams would be good then, I'm running a 3071 and my mapper believes the engine was built with a lower compression, I'd like more kick before the turbo kicks in so what would be best?

Pete out of interest what cams do you have at the moment?

As far as I know atm mate they are standard, it's somethimg Iv considered for a while but reading all this is a mine field, I don't want to spend a load of money on cams to find the ones I have brought are a waste of time, I'd like more low down grunt off boost but don't want it to take any mid or top end power?!?!

PartyPete wrote:As far as I know atm mate they are standard, it's somethimg Iv considered for a while but reading all this is a mine field, I don't want to spend a load of money on cams to find the ones I have brought are a waste of time, I'd like more low down grunt off boost but don't want it to take any mid or top end power?!?!

Which exhaust housing?

Hks do seem to be around the best there with the highest safe lift without too much duration, but surely its still going to move the powerband up a smidge, albeit with more midrange, they do a 256 with a lift of 11.5mm for the s14 but not for us unfortunately which is a shame as I think they would be the winner.

Its all very complicated and to be honest im getting tired of doing hours of research. haha, if we just rag the tits off the car all the time then it wont be a problem, but that will just make me crash again.

also look at Tomei 260 - 12mm

also note HKS 264 not have 12mm lift, it 11mm In , 10.5mm EX

Good shout didnt know about them! What else is out there?

I'm on a .86

Mr B wrote:also look at Tomei 260 - 12mm

Actually my old tomei cams were 260's, dont think they make 264s, my bad

^ Good cams them Tomei 260's . they do 270's & 280's with 12.5mm . Can get them quite cheap too .

Mr B wrote:^ Good cams them Tomei 260's . they do 270's & 280's with 12.5mm . Can get them quite cheap too .

What are they like low end though? Same duration as pipers but with the full 12mm lift. Wonder how noticeable the difference is between them

I've never driven a car with the tommi cams but I do however have a car in that has them fitted but unfortunately it's a non runner and the engine will be stripped down for inspection.
I would hazard a guess and say they would work well given the point you both have similar setup

Bit hit and miss here though but if I were going for a cam and I had similar mods I think I would plump for either the Kent or kelfords

If you are going to move those tomeis on then bear me in mind bob if they are the 260. Im still considering going back to stock though.

the kents dont make much sense to me but I dont know a huge amount about all this a 252 with decent lift would be better.

Kelfords would also move things further up again more so than the hks but with less lift.

Theres also the possibility that im talking rubbish.

.

Run a 264 hks inlet and standard exhaust cam works well so i hear

johnny gtir wrote:Run a 264 hks inlet and standard exhaust cam works well so i hear

I've seen this done on 2 different cars Johnny and it really doesn't work well, we ended up fitting 2 std cams back in both cars and the difference in the pick up from what they were was massive
Think I know who said this was a good idea though  lol