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

[GTR_JOEY]

Lol "didn't feel 100%"

Still does 10.8

[Piggaz]

Good bloody effort though.

What's the plan of attack? Another stock engine? Rebuild? Stroker?

[GTR_JOEY]

LS1 transplant? Haha

[sneakey pete]

Im in need of cams, simikiar turbos and goals as above.

Have read thread, am now more confused.

Frok what I understand, it Seems like the main 250 options out there are the mines cams, tomei, and there's a few others around with 256ish degrees. Ramp rates on all are up in the air and possibly not the greatest except maybe the mines?

So, what actual cams I can buy to get...

[fatz]

Swap stocker in and party again

[Dose Pipe Sutututu]

Swap stocker in and party again

+ ARP studs and boost errday

[SimonR32]

Swap stocker in and party again

Fatz is onto it!

Stocker with ARP head studs, Reimax oil pump, Ati balancer and Trust sump swapped over then party

[bcozican]

^^ then hopefully not the merry go round I went on after my engine lasted years and then had to swap it out

[sneakey pete]

I don't like my sump getting ripped off so I'll pass on the trust extension.

I suppose keeping stock cams isn't something is considered.

Motor is dead, to be replaced by stroker, head is getting a full redo, valve springs, new valves and the like. Turbos will be gtx2860s, similar to -5s but should like more boost.

Still saying stock cams knowing that?

[SimonR32]

I don't like my sump getting ripped off so I'll pass on the trust extension.

That's a fairly naive view, the sump sits directly between the two front wheels. Although it's not impossible to hit, you have to be fairly pro to manage it

[sneakey pete]

It was a bit of a poke at the fact it sits rather low compared to some of the other options out there. Went with a hioctane one for mine.

[sneakey pete]

Leaning towards type R's at this stage. Extra lift and duration should help a tad. Seems like the mines cams are really the go to option, but a purchase price of 1850 bucks plus postage, import duty etc... not so great.

[SimonR32]

Ok so a bit of an update. I went to 250 Type-R poncams, lost top end (probably 20-30hp at 700hp) and matched bottom end but the old head did have the intake squish removed so it's not a direct comparison.

Type-R cams are now out Type-B cams are in and should get a retune in next few week, so it'll be a direct back to back...

In the mean time I went a little nuts and figured I may as well build my old head so I now have a Tomei 1.2mm gasket, Supertech valve guides, Kelford 270-274/274 10.8mm split intake cam gears, Tomei cam studs and other stuff. So should be interesting how these split lobe jobbies work

[sneakey pete]

I also went nuts and got Unigroup cams.
Also changed turbo setup and a few other things.
Car might actually be on a dyno in the next month too!

[SimonR32]

15 hours ago, SimonR32 said:

Ok so a bit of an update. I went to 250 Type-R poncams, lost top end (probably 20-30hp at 700hp) and matched bottom end but the old head did have the intake squish removed so it's not a direct comparison.

Type-R cams are now out Type-B cams are in and should get a retune in next few week, so it'll be a direct back to back...

In the mean time I went a little nuts and figured I may as well build my old head so I now have a Tomei 1.2mm gasket, Supertech valve guides, Kelford 270-274/274 10.8mm split intake cam gears, Tomei cam studs and other stuff. So should be interesting how these split lobe jobbies work

So interesting result so far, went for a drive with the Type-B's (260) today, getting boost 300rpm earlier in 4th gear to the Type-R (250). Was 3900rpm in 4th to get 1.0bar and now it's 3600rpm with the Type-B. No other changes, same tune and cam gear settings...

Go figure, a lot different to what some would lead you to believe

[No Crust Racing]

That matches up more so with what Camtech and Kelford told me. 

Both said that I could maintain/improve response, mid range and top end by using one of their cams - both were in the 260-264 duration range and increased lift over stock.

Yet everyone here says more duration = worse response. 

[r32-25t]

We've got dyno sheets and compression tests that prove how much they ruin the bottom end but yeah go and buy a set cause the placebo effect of the lumpy idle fixes everything

[No Crust Racing]

You're not convincing me one way or the other, there's far too many conflicting opinions and dyno sheets for there to be a clear answer to this. 

 

Every engine/turbo/cam choice/dyno read out combo seems to say slightly different things - As per the above example (which is the opposite result of many of the other examples we've also seen). 

 

[Piggaz]

On 10/10/2014 at 8:26 PM, Piggaz said:

They're an Alfa Romeo NA lobe which uses a 32 mm base circle (stock lifters). Camtech grind them up.

I'll get the specs one day and post them up. But what we wanted was short duration and biggish lift with an agro ramp rate. HKS step 2 springs wernt enough to keep the bucket on the lobe with anything more than 19 psi and 5700 rpm iirc.

After spinning up a JUN 264 at 10.5 and Tomei 270 at 10.25, Yavuz located this lobe and used it.

There is another set. 262 at 11.3 iirc, once again with an agro rate.

I'll get the finer details next time I'm out there (if he is ok with making the info public).

A couple years on and I FINALLY got a few finer details. I had these doctored myself. Unfortunately I don't have the digits for the JUN and the Tomei shafts. All I got from Yavuz was they are "quite mild".

The 50 thou duration of the UE "260" is 232.34 degrees. That has 10.85 mm of lift.

The Step 2 V cam "264 @ 8.7 mm" was 222.xx. @ 50 thou

I reground the v cam camshaft and it cam back at 229.xx at 50 thou. That ended up having 10.25 mm of lift.

Doing some sniffing around I came across the Camtech "260 @ 9.15 mm drop in" That also has a 50 thou duration of 232. 

http://www.camtechcams.com.au/niss_6cyl_rb26.html

Funnily enough the "264 and 272" set below the "260" has the duration at 50 thou at 230 and 238.

So, a 260 has a 232, yet a 264 has a 230. WTF?

Look at the differences between the camtech and the HKS shafts. Both "264's" but there is 8 degree's difference at 50 thou. Sorta throws a curve ball into the mix huh.

[Lithium]

6 minutes ago, Piggaz said:

Look at the differences between the camtech and the HKS shafts. Both "264's" but there is 8 degree's difference at 50 thou. Sorta throws a curve ball into the mix huh.

 Yes!  I remember having an extensive debate on this topic with people from here ages ago, just looking at advertised duration tells so little of the picture - if you're throwing advertised duration with no consideration for lift, the cam profile itself, lobe separation angles, where the valve events occur relative to the piston position, other modifications etc then you're not really commenting on something you know enough about to make an authoritative statement on... ESPECIALLY if questioning someone like Kelford Cams whose cams are sitting in the engines of some of the fastest time attack cars in the world, among other things.

There are always trade offs somewhere, but making a sweeping statement about how a car is going to perform regardless of displacement, stroke, compression, porting, manifolding, turbo choice, cam degreeing etc based off longer or shorter duration >.35mm lift is rather silly.