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

[niZmO_Man]

Hmm, what would be interesting to see is the cam lobe shape, e.g. those Tomei 250° and 260° cams.

[Piggaz]

2 hours ago, ActionDan said:

He also added:  No problem what so ever Dan I’m glad to help, just for a matter of interest Tomei pon cams are 9.15mm cam lift on both and are 8.7mm valve lift on the intake and 8.77mm on the exhaust, that also means they run very large ramp heights or in other words big valve clearances, that says the lobe is lazy and will have more seat timing that inherits a loss in throttle response, just thought I would put that out there.

Funnily enough, JAGR33 who used to be quite an active member on here put 260 poncams in then ripped them back out for OEM bump sticks for this very reason. "What looked good on a dyno sheet didn't translate into the real world".

[SimonR32]

Nice to get the feedback ActionDan, looks like they definitely know their shit and use their experience to design cams that will work.

PS. Half way through writing this post my new Kelford sticks just got placed on my desk at work 

[No Crust Racing]

Have still been chatting to Kelford about cams, Josh said he would recommend springs at this boost. 

 

Something else crossed my mind. If I did put these cams in, and he's right about there being 10-12% gain, that would put me around/maybe over 500rwhp. It's a stock bottom end, how much can they take? 

[Dose Pipe Sutututu]

much more, provided you don't choke up the hot side.

[No Crust Racing]

Josh reckons it will not only make that power, but do it on less boost because it will flow more efficiently, that's gotta be a good thing. 

[Dose Pipe Sutututu]

yeah because the motor is more efficient further to the right thus less boost is required.. however power = exhaust flow.

[No Crust Racing]

Well if I did this, my aim would be to dial in the gears to try and not push it so far to the right, I can deal with peak not increasing much if response can be improved/area under the graph in total increased. 

 

 

[SimonR32]

On 27/10/2016 at 10:29 PM, SimonR32 said:

I literally just pulled one set of cams at 250deg 9.15 lift and replaced with 260deg 9.15 lift from the same manufacturer (Tomei). Changed NOTHING else and picked up 300rpm of boost response, so please tell me again how I'm wrong and it has hurt response?

Ok so I have to correct this a little. Turns out that there was 7 deg timing missing so it was helping it coming on a little better than it should. Tune is now done and dusted, Type B are 30rpm laggier (yes 30) and basically picks up 20hp as soon as it's on boost and holds it through top end and holds longer after peak power.

Basically for my application the Type-B are a much better option

Edited November 14, 2016 by SimonR32

[No Crust Racing]

Finally got some info for people playing along at home. Copy paste from build thread. 

Maxxed out fuel pump at 20psi. Last time we ran 24ish.

Need new pump then will take it back to finish it off. What to buy for intank? Currently has brand new direct wire 460lph Walbro. 

Detuned for now for safety making same power as before on only 16psi.

Slightly more responsive too, dialled for max response though and now with closed loop boost control. Power is better from the on boost onwards. Will get an overlay of new and old when I'm back there and it's finished but I've seen it myself. 

Will be good when finished off, but driving nicely at the moment.

Sounds like a f**king diesel with the valvetrain noise. Tuner said all clearances on the looser side of within standard specification and he likes them there. Can shim tighter if I want. Pros cons?

Dyno graph and vid of loud idle. 




 

 

[Dose Pipe Sutututu]

Run 3.5bar base fuel pressure, delete the in tank damper/pressure relief valve (if it's there).

Tell your tuner to derive the RPM from the road speed. You set this in the Analyse Screen (F2) and it's under Settings Menu -> Derived RPM vs Speed. Increase the load hold speed to about 100km/h, run the car up to that speed and hit learn (or whatever the button is called).

Hate seeing dyno sheets without RPM and yeah those torque figures are through the roof because there's no RPM.

[niZmO_Man]

Hahah 1,000 Nm, nice diesel engine brah.

[Lithium]

Just to confirm, are these the Kelford split duration cams?  And upgrading from a set of Tomeis?  Or something different?

Cheers.

[No Crust Racing]

 R34 GTR Stock cams -> Kelford L182A Cams

+ BC Springs. 

[SimonR32]

6 hours ago, ActionDan said:

Sounds like a f**king diesel with the valvetrain noise. Tuner said all clearances on the looser side of within standard specification and he likes them there. Can shim tighter if I want. Pros cons?

The valve clearances come on the cam spec sheets. I'm fairly sure Kelford clearances are a good 0.1mm tighter than standard and almost certain you will need much thicker shims

[No Crust Racing]

Has been discussed with Kelford and Tuner, will go back...