Installshield's NA Build
- Thread starter Installshield 2
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View attachment FS-DE cam profiles.xlsHere is a little cam crossreference I put together from the info on protegefaq.net. Scrolling up and down was killing me....
Also, wouldn'd factory overlap be @ 0.003" since that is where the published duration numbers are taken? Install, your numbers for the twiggy overlap look about right for 0.050" lift. I think that is why there was some confusion about how agressive those MSF cams were.
Also, wouldn'd factory overlap be @ 0.003" since that is where the published duration numbers are taken? Install, your numbers for the twiggy overlap look about right for 0.050" lift. I think that is why there was some confusion about how agressive those MSF cams were.
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Installshield 2
Gothenburg Superiority
No problem man, i 'run on' all the time...and i guess this is the proper place for it...
And yeah, you kind of answered yourself...max brake torque is a combination of max volumetric efficiency happening with the right timing with what you have control over...max VE will become a constant once the valves, cams, bottom end geometry, etc are set...there will be a physical engine speed in which the engine sucks in the largest volume of air...but ignition timing and fuel requirements can be adjusted...So ideally, you build the engine to get max VE where you want it, and peak HP where you want it...then set the ignition timing at the best possible angle on the crank...its a little more artistic than scientific when it comes to that, as to get the max expansion to happen at the correct crank angle, you have to light the fire significantly before that...and considering differences in fuel ratio, fuel quality, humidity, ambient temp, elevation, etc...all have an effect on how fast that kernel expands; it takes a lot of years to master that sort of thing...
Installshield 2
Gothenburg Superiority
Sport 23...I think you found it...and nice table, bud.
In all those posts i haven't seen anything but seat duration posted for factory spec cams...if thats all that mazda gave out, it seems its pretty unlikely that overlap numbers are anything but .003" also...if you look at your table exhaust closing and intake opening (i'm assuming this is info from the .003" also)...gives 17.5 degrees for the ZE intake and unrevised exhaust cams...i'm now fairly sure Mazda's posted overlap figures are seat to seat, 'usable' overlap at .050"...which is where most figures for Twiggy's are posted...
Ice...yeah i'll have to look into the exhaust cam i now have...it physically looks identical to the intake cam lobe wise...i haven't measured anything of course, and i guess LSA, and therefor overlap, isn't something the naked eye could detect...
If we're taking overlap numbers from seat to seat, instead of the more traditional .050"...that is where your 45 degree figure is coming from, right?
In all those posts i haven't seen anything but seat duration posted for factory spec cams...if thats all that mazda gave out, it seems its pretty unlikely that overlap numbers are anything but .003" also...if you look at your table exhaust closing and intake opening (i'm assuming this is info from the .003" also)...gives 17.5 degrees for the ZE intake and unrevised exhaust cams...i'm now fairly sure Mazda's posted overlap figures are seat to seat, 'usable' overlap at .050"...which is where most figures for Twiggy's are posted...
Ice...yeah i'll have to look into the exhaust cam i now have...it physically looks identical to the intake cam lobe wise...i haven't measured anything of course, and i guess LSA, and therefor overlap, isn't something the naked eye could detect...
If we're taking overlap numbers from seat to seat, instead of the more traditional .050"...that is where your 45 degree figure is coming from, right?
Yah, I assumed as such due to the duration numbers as well. Its just that JDM cams have close to no overlap at .050? That just doesnt really seem quite right for a an engine thats meant to be in a sporty car. But then mazda did skimp on the sporty car over here.
Honestly dude I have no idea which set of numbers ive used (cant remember), given the only numbers published that I can remember atm are the numbers crazeed posted here: http://www.mazdas247.com/forum/show...sults-thread&p=4412597&viewfull=1#post4412597
I most likely used those and just didnt calculate correctly. I added the intake opening time and the exhaust closing time to calculate the overlap. If thats correct that means that while the duration posted was at .050 and the rest of the details at some unknown measurement of lift...
EDIT: Yah i used crazeeds numbers, they add up correclty anyways to give a value of 45.2.
Slightly off topic here... Looking at the table I posted, FP and FS exhaust cams are the same but pinned differently. It looks like an NA engine with an FP exhaust cam would have 8deg overlap. Do you think that would be a decent way to shift the powerband up on an NA motor with a few bolt ons?
You'd gain an extra degree over the FS Cam, IIRC if you repin the FP intake cam youll get more albeit with less duration.
Seem to recall reading that somewhere. Even better would be to have the stock JDM FS intake repinned, or buy installshields CS Cam if hes selling it
Seem to recall reading that somewhere. Even better would be to have the stock JDM FS intake repinned, or buy installshields CS Cam if hes selling it
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Installshield 2
Gothenburg Superiority
Ah, Ice...i see what happened...
Crazee D posted Exhaust closing in ABDC, not BTDC...While that info is accurate and correct, you can't use it to find overlap directly...that is where all the extra overlap is coming from @ .050"...
To find overlap by that method you have to use either relationship to BDC or relationship to TDC for both events...meaning, you need to add exhaust closing around TDC and intake opening around TDC...not one and the other...
My stuff is showing Exhaust closing past .050" @ 6.59 degrees ATDC of the exhaust stroke, Intake cam is opening past .050" @ 4.77 BTDC of the exhaust stroke...giving 11.36 degrees of event overlap at .050" lift on the exhaust stroke...The only reason i'm trusting this is because Andrew himself posted it a few times...While i'm deriving that info from FI cams, i found a few posts of andrews claiming the LSA is 12 degrees different between FI and NA twiggys....and that is where i'm finding the event timing degree...this overlap figure should be accurate if that LSA difference is, but if the LSA is more or less than a 12 degree difference, the overlap will quickly change with it...
you can also see how this is a pretty intake biased overlap figure...The intake valves are being opened pretty early on the exhaust stroke, allowing the cylinders to 'push' against the incoming air...and definitely a reason that twiggys without gears seem to punish low speed operation pretty good...and another reason that these cams seem to respond extremely quickly to a little intake retard (making the intake opening event happen a little closer to TDC, as apposed to so far before it...overall a little 'later' in the cycle)...that very quickly 'fixes' the idle to nearly stock...
As far as the factory numbers again...overlap at .003" vs. .050" doesn't necessarily mean .050" will be far less...that will depend on the nose shape (ramp angle, area, etc.)...and that is where similarities with the twiggys quickly go away...the factory cams seem to use pretty aggressive angles, but with a pretty low duration...a sharp RA could actually 'hold' that overlap pretty well up to a certain lift...so its still possible that they have some usable overlap at .050" (especially the really aggressive MSF exhaust cam), but my guess is it hits about .050", then is over...where as the twiggy's will keep overlap up through a significantly higher lift past .050"...and holding that overlap longer is more a function of their large duration, not just the ramp angle and lobe separation figure...
its just another reason that overlap on its own is not a great way to compare cams of different specs...its just one of many important measurements...
Crazee D posted Exhaust closing in ABDC, not BTDC...While that info is accurate and correct, you can't use it to find overlap directly...that is where all the extra overlap is coming from @ .050"...
To find overlap by that method you have to use either relationship to BDC or relationship to TDC for both events...meaning, you need to add exhaust closing around TDC and intake opening around TDC...not one and the other...
My stuff is showing Exhaust closing past .050" @ 6.59 degrees ATDC of the exhaust stroke, Intake cam is opening past .050" @ 4.77 BTDC of the exhaust stroke...giving 11.36 degrees of event overlap at .050" lift on the exhaust stroke...The only reason i'm trusting this is because Andrew himself posted it a few times...While i'm deriving that info from FI cams, i found a few posts of andrews claiming the LSA is 12 degrees different between FI and NA twiggys....and that is where i'm finding the event timing degree...this overlap figure should be accurate if that LSA difference is, but if the LSA is more or less than a 12 degree difference, the overlap will quickly change with it...
you can also see how this is a pretty intake biased overlap figure...The intake valves are being opened pretty early on the exhaust stroke, allowing the cylinders to 'push' against the incoming air...and definitely a reason that twiggys without gears seem to punish low speed operation pretty good...and another reason that these cams seem to respond extremely quickly to a little intake retard (making the intake opening event happen a little closer to TDC, as apposed to so far before it...overall a little 'later' in the cycle)...that very quickly 'fixes' the idle to nearly stock...
As far as the factory numbers again...overlap at .003" vs. .050" doesn't necessarily mean .050" will be far less...that will depend on the nose shape (ramp angle, area, etc.)...and that is where similarities with the twiggys quickly go away...the factory cams seem to use pretty aggressive angles, but with a pretty low duration...a sharp RA could actually 'hold' that overlap pretty well up to a certain lift...so its still possible that they have some usable overlap at .050" (especially the really aggressive MSF exhaust cam), but my guess is it hits about .050", then is over...where as the twiggy's will keep overlap up through a significantly higher lift past .050"...and holding that overlap longer is more a function of their large duration, not just the ramp angle and lobe separation figure...
its just another reason that overlap on its own is not a great way to compare cams of different specs...its just one of many important measurements...
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I am just about to go with the FP exhaust cam.
Mate just finished putting the FS intake cam into his FP.
Made a great difference and now he is looking into using the FS intake cam as his exhaust cam
for even more overlap!
judging from the FS intake cam into the FP... it definitely shifted the power curve higher... no more faceplanting after 6000 rpm lol.
Mate just finished putting the FS intake cam into his FP.
Made a great difference
and now he is looking into using the FS intake cam as his exhaust cam for even more overlap!
judging from the FS intake cam into the FP... it definitely shifted the power curve higher... no more faceplanting after 6000 rpm lol.
I am just about to go with the FP exhaust cam.
Mate just finished putting the FS intake cam into his FP.
Made a great difference
for even more overlap!
judging from the FS intake cam into the FP... it definitely shifted the power curve higher... no more faceplanting after 6000 rpm lol.
Don't know why you are going with the FP exhaust cam in an FS engine:
- less valve lift
- less duration
- no real difference in valve closing position
The FS intake cam into FP engine makes sense and on paper looks like a decent upgrade.
Installshield 2
Gothenburg Superiority
Yeah man which engine are we talking about haha?
Installshield 2
Gothenburg Superiority
meaning stock FS US intake cam and an FP exhaust cam? Sorry, i didn't look over it, does the FP exhaust cam need to be repinned?
the FP cams are even more mild than the FS cams...FS cams have been put into FPs in the past, i've seen that...it gives the 1.8L a little better lowend, with little to no difference up high...their geometry is already better for higher rpm, but the lack of stroke gives them a pretty 'civic like' low end curve...
never heard of it the other way around...the lack of FS topend comes from a bottom end that loves duration...the pistons move so fast at upper rpm, the first thing to make a lot of difference is simply duration...Overlap obviously gives great benefits, but its one of those more specific things that needs to be tuned...even with twiggys; 90% of the noticeable impact at upper rpm comes from the duration...not the overlap...
so i guess what i'm saying is best bet would be to look for cams that give duration first...then overlap 2nd...if you can only pick one, i'd say more duration with a little less overlap is always better for an FS than less duration and more overlap...ideally you want both; just listing order of importance imo...
I am just about to go with the FP exhaust cam.
Mate just finished putting the FS intake cam into his FP.
Made a great difference
for even more overlap!
judging from the FS intake cam into the FP... it definitely shifted the power curve higher... no more faceplanting after 6000 rpm lol.
As I said on AGT, your better off repining the FS intake cam then using the FP cam as your only gaining one degree of overlap and reducing duration.
Azza has a JDM FS-DE. His friend which hes referring to has a JDM FP.
OK so would this be correct in saying that due to the high rpm breathing being affected by its rod ratio the breathing at higher rpms is affected and thus duration becomes more effective in opposition to overlap? Or is there something else at play that im missing?
EDIT: Nvm just remembered about how rod ratio affects the piston at TDC. Still I wonder if its purely this or if there's anything else about these engines that corresponds to duration being more effective? i.e. head design or such.
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I probably should have qualified my earlier post by saying that I was talking in terms of the Australian delivered FS and FP engines.
I was responding more to Azza SP20's idea.
Generally agreed that in the US case the FP swap could be of benefit.
Might be better to get some JDM cams (FS would be best for the greater duration).
I was going off Edwin's numbers for USDM FP and FSes. According to what I posted in the table the exhaust cam is the same between the USDM FP and FS except that the FP exhaust cam is advanced 4 degrees.
Update on the TB/idle adjustment. I looked at an older 626 FS TB (same as ours just an older revision.) The AAS adjustment does adjust the amount of air that can bypass the IAC and throttle plate.
Basically, TAS adjusts the physical stop to the throttle plate (and will alter the TPS reading.) It is calibrated at the factory and shouldn't need to be touched. Consider the TAS a course adjustment. AAS is a much smaller channel; consider it fine tune.
I quickly tried grounding the TEN pin to adjust my idle the other day and couldn't get it to work. My car wasn't warmed up and was still on fast idle so it's possible the ECU simply ignored the grounding of the TEN pin. Unfortunately, I haven't gotten to try it again... maybe later today.
I think one of two things is happening to reset the idle (maybe both.) I think that the ECU turns the IAC off or sets it to a midrange state and/or learns a new target idle rpm when the TEN pin is grounded. I was monitoring the IAC duty cycle to see what happened but I my attempt to change the idle was unsuccessful so I will have to try again.
Update on the TB/idle adjustment. I looked at an older 626 FS TB (same as ours just an older revision.) The AAS adjustment does adjust the amount of air that can bypass the IAC and throttle plate.
Basically, TAS adjusts the physical stop to the throttle plate (and will alter the TPS reading.) It is calibrated at the factory and shouldn't need to be touched. Consider the TAS a course adjustment. AAS is a much smaller channel; consider it fine tune.
I quickly tried grounding the TEN pin to adjust my idle the other day and couldn't get it to work. My car wasn't warmed up and was still on fast idle so it's possible the ECU simply ignored the grounding of the TEN pin. Unfortunately, I haven't gotten to try it again... maybe later today.
I think one of two things is happening to reset the idle (maybe both.) I think that the ECU turns the IAC off or sets it to a midrange state and/or learns a new target idle rpm when the TEN pin is grounded. I was monitoring the IAC duty cycle to see what happened but I my attempt to change the idle was unsuccessful so I will have to try again.
Installshield 2
Gothenburg Superiority
sport 23...from what i can tell the IAC is the main control the ecu will use to keep the idle at 750 rpm...The TAS will physically adjust the TPS also, so you'll quickly get things very out of whack if you mess with that too much...unless of course, like above, you have a standalone and can re calibrate the TPS easily...
if you adjust the AAS screw, you're adjusting the air that gets by the plate AND IAC it looks like...The IAC functions in 260'ish 'steps', which the ecu will earn over time...this is how, if you don't ground the TEN pin, the ecu simply adjusts those 'steps' to something else...to keep the idle at 750...
so for comparison, to my understanding as to what happens...if you back out the AAS, you physically let more air into the engine at idle...this on its own will 'race' the idle slightly...so the IAC then closes slightly more to keep the idle in check...If you jump the pin (the FSM does say 'after warm up', so maybe that is why its getting messed up?), the computer will accept those changes, and therefor not step the IAC around the higher idle speed...
so i'm pretty sure that is how the factory computer is 'learning' around the AAS adjustment...the IAC actually has a pretty big swing in steps...as its opened nearly all the way for a cold start, and that is what parks the cold start idle up near 1800 rpm if its cold enough...and after 30 seconds or so, it slowly starts closing off and lowering the idle...and opening the AAS lets more air in, the idle is raised...but the computer quickly 'sees' that, and closes the IAC slightly to bring the speed back down...overall letting the same amount of air in, its just less through the IAC and more through the AAS passage...if that makes sense...
in my case, thats all it took...the IAC has some built in limits it looks like...where as it'll only open so far for a warmed engine...that fully opened position and the factory AAS settings...didn't let my engine do anything but stall on throttle lift with the twiggys...400 miles since i backed out that AAS three full turns, haven't come close to a stall since...despite idle being at the exact same speed...all i'm saying is with some engine modification, you may have to adjust the timing of the IAC stepping, rather than actually raising the idle speed...after the adjustment; not a single problem of any kind...i'm hoping i beat it...
if you adjust the AAS screw, you're adjusting the air that gets by the plate AND IAC it looks like...The IAC functions in 260'ish 'steps', which the ecu will earn over time...this is how, if you don't ground the TEN pin, the ecu simply adjusts those 'steps' to something else...to keep the idle at 750...
so for comparison, to my understanding as to what happens...if you back out the AAS, you physically let more air into the engine at idle...this on its own will 'race' the idle slightly...so the IAC then closes slightly more to keep the idle in check...If you jump the pin (the FSM does say 'after warm up', so maybe that is why its getting messed up?), the computer will accept those changes, and therefor not step the IAC around the higher idle speed...
so i'm pretty sure that is how the factory computer is 'learning' around the AAS adjustment...the IAC actually has a pretty big swing in steps...as its opened nearly all the way for a cold start, and that is what parks the cold start idle up near 1800 rpm if its cold enough...and after 30 seconds or so, it slowly starts closing off and lowering the idle...and opening the AAS lets more air in, the idle is raised...but the computer quickly 'sees' that, and closes the IAC slightly to bring the speed back down...overall letting the same amount of air in, its just less through the IAC and more through the AAS passage...if that makes sense...
in my case, thats all it took...the IAC has some built in limits it looks like...where as it'll only open so far for a warmed engine...that fully opened position and the factory AAS settings...didn't let my engine do anything but stall on throttle lift with the twiggys...400 miles since i backed out that AAS three full turns, haven't come close to a stall since...despite idle being at the exact same speed...all i'm saying is with some engine modification, you may have to adjust the timing of the IAC stepping, rather than actually raising the idle speed...after the adjustment; not a single problem of any kind...i'm hoping i beat it...
Installshield 2
Gothenburg Superiority
We were just talking about this a bit ago...good stuff.
https://www.youtube.com/watch?v=Bch5B23_pu0&feature=youtube_gdata_player
https://www.youtube.com/watch?v=Bch5B23_pu0&feature=youtube_gdata_player
I was really hoping to see that Saab run! I wonder what the NVH is like. Valves opening and closing near instantly will create some interesting noises as seen on the test rig. I wonder if the engine oil is a enough of a cushion to make it acceptable for the general public. Whenever they get this technology mainstream it will be time for a new car!!
