Keethos 842 Report post Posted May 29, 2015 Yes, very interested in what you have planned......will you be going back to the Sprintex or will you be trying something else? Share this post Link to post Share on other sites
JamesP1991 222 Report post Posted May 29, 2015 What kind of N/A developments are you testing? Share this post Link to post Share on other sites
KevinA 695 Report post Posted May 29, 2015 Mark somebody needs to sort cams !! Share this post Link to post Share on other sites
Mark@Abbey M/S 235 Report post Posted May 29, 2015 Cams at the moment means Pistons with bigger valve cut outs! Share this post Link to post Share on other sites
Mark@Abbey M/S 235 Report post Posted May 29, 2015 Kethos, think we will use a HKS V2 for some FI development think we can push these motors for some big numbers with a centrifugal charger. N/A tuning I want to see what the manifolds available actually show on our in house dyno. 1 Quixote reacted to this Share this post Link to post Share on other sites
Keethos 842 Report post Posted May 29, 2015 Ooooh exciting times....so what will happen to the current Sprintex kit? This may be a bit of a silly question but I can understand getting forged internals to withstand more power from FI but what benefits can an NA car get from forged internals? Share this post Link to post Share on other sites
Guest Report post Posted May 29, 2015 Piper make a range of cams for the FA20. They work with stock Pistons. Share this post Link to post Share on other sites
Mark@Abbey M/S 235 Report post Posted May 30, 2015 Sprintex has been sold on to a customer. In N/A trim only reason to go forged is to gain capacity. Nigel that's good info I presume they have only added new duration to the cam spec? 1 Quixote reacted to this Share this post Link to post Share on other sites
Lauren 2259 Report post Posted May 30, 2015 Will be no more lift if they work, but given the duration is variable with the VVTi is there really much to gain by that? Keith if you went for forged rod, a higher rev limit is possible. Thought the crank was already forged and strong anyway. If we're talking cams, we're talking higher revs anyway. Share this post Link to post Share on other sites
Kodename47 446 Report post Posted May 30, 2015 Will be no more lift if they work, but given the duration is variable with the VVTi is there really much to gain by that? AVCS (we have a Subaru, use the correct terms) doesn't affect duration. Duration is the amount of cam angle where the valve is open, the cam lobes can't magically be re-ground by the ECU. Share this post Link to post Share on other sites
Mark@Abbey M/S 235 Report post Posted May 30, 2015 But it means a cam has a lot longer duration as the cam cam be advanced then retarded from the zero position. see below HKS specification Share this post Link to post Share on other sites
Special K 442 Report post Posted May 30, 2015 Mark, I thought the increased lift of the HKS cams was to allow for the stroked crank (less the reduction in piston height)... although 0.7mm doesn't sound a lot.. Spec K Share this post Link to post Share on other sites
Mark@Abbey M/S 235 Report post Posted May 30, 2015 Mark, I thought the increased lift of the HKS cams was to allow for the stroked crank (less the reduction in piston height)... although 0.7mm doesn't sound a lot.. Spec K Keith, increased lift and increased capacity means more power. The HKS pistons have a bigger valve cut out than the stock piston for the increased lift. The increase in compression comes from the longer stroke I think but I think they have lifted the big end gudgeon pin up in the piston or using a shorter rod to allow for the extra stroke. Share this post Link to post Share on other sites
Guest Report post Posted June 1, 2015 Piper Cams have increased lift and duration? They don't list them on their site yet, but someone like Mark could probably get the info from them for us.I can confirm that one of the models they offer has a 12.35mm lift on the inlet, with a 284 degree duration. The exhaust has 12.00mm lift and a 274 degree duration. 59 degree overlap.The others range from 11.30 to 12.00mm lift and 262 to 272 duration.All this is well and good, but we must remember the shitty spring seat pressures of these engines in stock form and also the probable unreliability of the roller rockers if asked to do more work.. Share this post Link to post Share on other sites
Lauren 2259 Report post Posted June 1, 2015 AVCS (we have a Subaru, use the correct terms) doesn't affect duration. Duration is the amount of cam angle where the valve is open, the cam lobes can't magically be re-ground by the ECU. Fair enough, AVCS, but changing the timing of the cams alters the duration does it not? Share this post Link to post Share on other sites
Sonic 4 Report post Posted June 1, 2015 Piper Cams have increased lift and duration? They don't list them on their site yet, but someone like Mark could probably get the info from them for us. I can confirm that one of the models they offer has a 12.35mm lift on the inlet, with a 284 degree duration. The exhaust has 12.00mm lift and a 274 degree duration. 59 degree overlap. The others range from 11.30 to 12.00mm lift and 262 to 272 duration. All this is well and good, but we must remember the shitty spring seat pressures of these engines in stock form and also the probable unreliability of the roller rockers if asked to do more work.. Agreed, some images on the american site regarding the rockers look like you've got to be pretty careful about just whacking in a set of springs and going for 9K rpm, nice though that would be Share this post Link to post Share on other sites
Guest Report post Posted June 1, 2015 Fair enough, AVCS, but changing the timing of the cams alters the duration does it not? I think the variable Cam timing will change the actual timing and possibly the overlap, but, unless it is fast enough to alter the cam position relative to the crank during valve opening, it won't alter duration. Share this post Link to post Share on other sites
Kodename47 446 Report post Posted June 1, 2015 Fair enough, AVCS, but changing the timing of the cams alters the duration does it not?No, it moves the valve opening/closing earlier or later by retarding/advancing the cams. It doesn't work by purposefully rotating the cams while the valves are open, I doubt the oil actuation would be quick enough. Obviously there may be a chance of minimal duration change as the cams move but that's not the intended operation. Share this post Link to post Share on other sites
Mark@Abbey M/S 235 Report post Posted June 2, 2015 The cam control allows you to move the cams to give the best VE ( volumetric efficiency) through out the RPM range the motor uses. A cam needs to be move advanced at lower RPM to allow the cylinder to be filled efficiency and more retarded at high RPM. NA and FI cams set up are normally a little different also you can move the powerband around by playing with cam angle. Share this post Link to post Share on other sites
smudge 1020 Report post Posted June 2, 2015 Probably a stupid question, but I assume the HKS cam kit compliments the differences the stroker kit makes? Share this post Link to post Share on other sites
Kodename47 446 Report post Posted June 2, 2015 Probably a stupid question, but I assume the HKS cam kit compliments the differences the stroker kit makes?More duration = intake valves open longer and exhaust valves open longer. Put simply, greater time to fill the extra capacity. Extra lift also helps with this. Share this post Link to post Share on other sites
smudge 1020 Report post Posted June 2, 2015 More duration = intake valves open longer and exhaust valves open longer. Put simply, greater time to fill the extra capacity. Extra lift also helps with this. Good stuff Share this post Link to post Share on other sites
Quixote 35 Report post Posted June 2, 2015 Mmm, more options...definitely a thread worth watching! Share this post Link to post Share on other sites
