Maxx Mazda
Contributor
- :
- Stock P5
Ya be careful running rich AFR's on the new engine, it'll wash out the cylinders and leave you with some bad ring sealing...
CulRidr's MP3 N/A build (~150whp goal)
- Thread starter CulRidr
- Start date
MAZDA_SPEED
Member
- :
- BLACK MSP
You should fab up ITB for more power.
Those are around the factory AFRs under full load (at least, they are on the australian version of the car) - theres literally giant big fat gobs of horsepower to be unlocked by fixing that problem
I hear ya...pulls were done with about 600kms on the engine, and the AFRs for anything under 4000 is in the high 13s/low 14s for the most so no worries there. Just did a ~700km road trip and the CEL has disappeared (I still hear some misfires). Got 569km before the fuel light came on, not bad for an untuned car with huge overlap cams...
The guy doing my reflash left for Italy for 3 weeks to tune some Ferraris before he had a chance to write the ECU so I'm just driving it now having some fun...some small issues I'm having:
1. When in neutral (to slow down), the revs bounce from 1500-2000 continuously instead of dropping down to idle speed...issue with having a very light flywheel?
2. Usually during a "cold start" (this happens very infrequently), I'll have NO power from throttle input AT ALL when trying to get going in 1st gear. On other occasions - again, after a cold start - I'll have a complete flat line of power (read: NO power) when shifting into 2nd gear from being around 3500-4000 in first gear (hitting around 2400RPMs in 2nd gear), only for the power to surge through in one jolt after a couple seconds of "nothing"...just ask my gf how she likes that (visualize her drinking water and then being splashed with a bunch of water from the jolt!)
3. Rough idle, but that's both because of the the tune (or lack thereof) and the "zero" timming of the cams. Presently going through the tuning thread for the twiggys to find out if there is info on where I should time them.
4. Some misfiring, most likely due to the aggressive timing of the MP3 ECU. Will be taken care of with the reflash. I had the CEL come up almost immediately when I first drove the car. It disappeared recently, but re-appeared in the last couple of days (need to read it to confirm that is is indeed still an 0300 code).
1. When in neutral (to slow down), the revs bounce from 1500-2000 continuously instead of dropping down to idle speed...issue with having a very light flywheel?
2. Usually during a "cold start" (this happens very infrequently), I'll have NO power from throttle input AT ALL when trying to get going in 1st gear. On other occasions - again, after a cold start - I'll have a complete flat line of power (read: NO power) when shifting into 2nd gear from being around 3500-4000 in first gear (hitting around 2400RPMs in 2nd gear), only for the power to surge through in one jolt after a couple seconds of "nothing"...just ask my gf how she likes that (visualize her drinking water and then being splashed with a bunch of water from the jolt!)
3. Rough idle, but that's both because of the the tune (or lack thereof) and the "zero" timming of the cams. Presently going through the tuning thread for the twiggys to find out if there is info on where I should time them.
4. Some misfiring, most likely due to the aggressive timing of the MP3 ECU. Will be taken care of with the reflash. I had the CEL come up almost immediately when I first drove the car. It disappeared recently, but re-appeared in the last couple of days (need to read it to confirm that is is indeed still an 0300 code).
i'd think its a combination of the light weight flywheel + cams. Higher compression will help with the cams to a degree due to the increased dynamic compression - having said that, twiggies plus light weight flywheel can be a little problematic to tune around but can be done if you don't mind a slightly higher idle. Solution to the problem is to dial in the cam gears to pull the overlap back to a more usable range. Theres some posts by Installshield about "blow down" and explainations as to why the FSDE doesn't respond to monster overlap with the stock rod length (explainations which exceed my understanding, cos I haven't really been bothered investigating) - but if you close the overlap you likely WILL make more power *everywhere* because according to Crazy D, by design the twiggies are set up to rev higher than you plan to rev your motor...
Having said that, WHAT cam gears do you have (take a picture please)? because most i've seen are incorrectly designed - and will cause problems with missfires and potentially non-running of the engine when adjusted (could explain your missfires now)
starting to sound like cam gear pickups to me - Could also be poor fueling - whats your fuel pressure doing? I had problems with lethargic power delivery until I swapped the filter out for a new one....
Close that overlap. Rough idle (specially a low rough idle) is cams + flywheel, welcome to race cam territory my friend...sucks bad at idle - par for the course....close the overlap a little to get some sanity about your idle.
Misfire could be poorly/incorrectly designed cam gears and pickups - but the twiggies are known to throw missfire codes on the US computer
Great post. I doubt the cam gears are a problem as Focus designed them, but I'll let you judge for yourself. I'll answer each of your replies with my own after the pic...
http://www.mazdas247.com/forum/showthread.php?t=123748308
I know about closing the overlap, but I don't know by how many degrees or in which direction. As for advancing/retarding, there were some links posted in the Twiggy tuning thread, but those links are dead so to make sure I don't screw it up, what way do you turn the camshaft (while keeping the main gear set in position) to advance/retard timing?
I'm still thinking the misfires are the overly aggressive timings of the MP3 ECU. It comes and goes, but not a big deal, yet.
And finally, how do I check my fuel pressure? According to scheduled maintenance, my car is due for a fuel pump filter maintenance procedure so it is possible that it needs to be replaced...never thought of that.
http://www.mazdas247.com/forum/showthread.php?t=123748308
I know about closing the overlap, but I don't know by how many degrees or in which direction. As for advancing/retarding, there were some links posted in the Twiggy tuning thread, but those links are dead so to make sure I don't screw it up, what way do you turn the camshaft (while keeping the main gear set in position) to advance/retard timing?
I'm still thinking the misfires are the overly aggressive timings of the MP3 ECU. It comes and goes, but not a big deal, yet.
And finally, how do I check my fuel pressure? According to scheduled maintenance, my car is due for a fuel pump filter maintenance procedure so it is possible that it needs to be replaced...never thought of that.
basically, the reason why high overlap doesn't work well on the FS engines is because of the mean piston speed
a short rod, long stroke means you have a low rod ratio... low rod ratio motors have high piston speeds and high cylinder side loads (thus shorter engine life)... the high piston speeds causes lower combustion chamber dwell times which means less air ingested and thus limited power output
higher rod ratio engines, such as the BP, and the Honda B16A for that matter is why you can run crazy overlap on them (they still have bad idle of course, unless you took advantage of VTEC) and still make better power... in otherwords, these engines have higher piston dwell times and therefore lower piston speeds... this is also a reason why you can rev the piss out of them and not throw a rod
obviously it doesn't end there and isn't that simple as far as how power is produced... combustion chamber design, cylinder head port design, valve angle design, intake and exhaust manifold design all play a role in this of course
finally, the other difference common between low and high rod ratio engines... torque... while it cannot be definitively based on bore/stroke, one can usually guess if its a high or low rod ratio engine (but you cannot determine the actual number without the rod length)... an undersquare engine like the FS will produce better low end torque compared to an oversquare (or square) one of similar displacement in theory... additional tweaks to head design, intake manifold design, exhaust design, etc can even things out or cause the FS to lose out... but point being is, longer stroke engines have more "leverage" thus this is also why truck engines have massive strokes that limits their revs to 2000rpm (or less)... the piston speeds and side loads are so great that it will snap like a twig if you try to rev it like a car engine... ship engines run at mere hundreds RPMs btw
I'm *really* generalizing here and there's obviously a lot more in depth than this... but this is just going off my head so far
FYI, the original MSF engine had 17.5 degrees of overlap... so that maybe the practical limit for the FS-ZE... this got dialed back to 10.5 degrees after issues happened with owners in cold areas
look at the cam lobes on the cylinder that's TDC... by looking at how they are pointing, you can roughly figure out what is 0 overlapGreat post. I doubt the cam gears are a problem as Focus designed them, but I'll let you judge for yourself. I'll answer each of your replies with my own after the pic...
http://www.mazdas247.com/forum/showthread.php?t=123748308
I know about closing the overlap, but I don't know by how many degrees or in which direction. As for advancing/retarding, there were some links posted in the Twiggy tuning thread, but those links are dead so to make sure I don't screw it up, what way do you turn the camshaft (while keeping the main gear set in position) to advance/retard timing?
I'm still thinking the misfires are the overly aggressive timings of the MP3 ECU. It comes and goes, but not a big deal, yet.
And finally, how do I check my fuel pressure? According to scheduled maintenance, my car is due for a fuel pump filter maintenance procedure so it is possible that it needs to be replaced...never thought of that.
basically, the reason why high overlap doesn't work well on the FS engines is because of the mean piston speed
a short rod, long stroke means you have a low rod ratio... low rod ratio motors have high piston speeds and high cylinder side loads (thus shorter engine life)... the high piston speeds causes lower combustion chamber dwell times which means less air ingested and thus limited power output
higher rod ratio engines, such as the BP, and the Honda B16A for that matter is why you can run crazy overlap on them (they still have bad idle of course, unless you took advantage of VTEC) and still make better power... in otherwords, these engines have higher piston dwell times and therefore lower piston speeds... this is also a reason why you can rev the piss out of them and not throw a rod
obviously it doesn't end there and isn't that simple as far as how power is produced... combustion chamber design, cylinder head port design, valve angle design, intake and exhaust manifold design all play a role in this of course
finally, the other difference common between low and high rod ratio engines... torque... while it cannot be definitively based on bore/stroke, one can usually guess if its a high or low rod ratio engine (but you cannot determine the actual number without the rod length)... an undersquare engine like the FS will produce better low end torque compared to an oversquare (or square) one of similar displacement in theory... additional tweaks to head design, intake manifold design, exhaust design, etc can even things out or cause the FS to lose out... but point being is, longer stroke engines have more "leverage" thus this is also why truck engines have massive strokes that limits their revs to 2000rpm (or less)... the piston speeds and side loads are so great that it will snap like a twig if you try to rev it like a car engine... ship engines run at mere hundreds RPMs btw
I'm *really* generalizing here and there's obviously a lot more in depth than this... but this is just going off my head so far
FYI, the original MSF engine had 17.5 degrees of overlap... so that maybe the practical limit for the FS-ZE... this got dialed back to 10.5 degrees after issues happened with owners in cold areas
Mean Piston Speed has absolutely NOTHING to do with rod ratio. Piston speed is a function of stroke and RPM (equation being Cm = .166 * L * N, where L is stroke length in inches, N is crank speed in RPM...solving Cm, Average Piston speed in ft/sec). In other words, no matter what length your rods, if your RPM and stroke don't change, your MPS will remain the same.
You're talking about piston acceleration (which is the reason for shorter engine life, not really piston side loading - higher piston acceleration leads to insane forces attempting to stretch the roads), which is a function of crank speed, RPM and rod ratio...
Gmax = ((N^2 * L)*2189) * (1 + 1/(2A))
solving maximum piston speed in Feet/sec squared, N is crankshaft speed in RPM, L is stroke in inches, and A is the rod ratio.
I have posted all this stuff before..i'm sure.
The high overlap has something to do with the blow down event, which you are right, has a great deal to do with the piston dwell.
Interesting on the practical limit of the FSZE with respect to overlap - but thats on FSZE cams. The twiggy cams have far higher duration and lift, which messes with the whole thing. I would have expected the higher compression to compensate for the agro idle a little by lifting the dynamic compression but perhaps not.
CulRidr - compare the overlap between the turbo and NA versions of the cams (0 degrees vs whatever they are), and go half way between as a starting point. Cam gears look fine, the pickups stay put relative to the cam pin - so thats cool. Check your fuel pressure with a fuel pressure gauge
Last edited:
you mean butt ugly... but they are well engineered
- :
- 02' Protege ES (Gone)
16' Mazda 6 sport manual
function over form anyday
No doubt...mine are a little nicer, the plate is mounted in the back, but designed in such a way that the adustment still moves independently of the pickups. Mind you, the guy that had mine made paid a stack to have them done...
- :
- MSP 1145
have the thing powder coated!!
thats what i was thinking too
