tis off topic...but police officers enforce rules they don't understand all the time... its in the rules - and enforcing said rules comes with the blue writing dude.
NA Tech Race to 100whp per 1000cc's
- Thread starter LordWorm
- Start date
tis off topic...but police officers enforce rules they don't understand all the time... its in the rules - and enforcing said rules comes with the blue writing dude.
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- 02' Protege ES (Gone)
16' Mazda 6 sport manual
Rod length / Stroke of Engine = Rod Ratio
But yes the FP motor has a slightly better rod ratio.
But yes the FP motor has a slightly better rod ratio.
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Yah well im assuming that the 3S-GTE rods are a viable option. If so then the rod ratio gets bumped up to around 1.63.
If mah maths is correct that should bring it within 9,000 rpm region as B18Cs have a similiar rod ratio.
Or cheaper alternative would be SR20 Rods which would be around 1.58, which is just a bit more then installshields rod ratio IIRC.
EDIT: LW 3SGTE rods in a FP what compression would that be? (Is there an equation?)
If mah maths is correct that should bring it within 9,000 rpm region as B18Cs have a similiar rod ratio.
Or cheaper alternative would be SR20 Rods which would be around 1.58, which is just a bit more then installshields rod ratio IIRC.
EDIT: LW 3SGTE rods in a FP what compression would that be? (Is there an equation?)
if memory serves theres a deck height difference between the FP and FS...which is why its not "as good" as it was once thought to be...
on the FS, the 3SGTE rods are viable but require extensive crank modifications.
my recipe included a novel idea of combining the FS block with the FP crank, using a honda K series rod and pushing near 1.7:1 rod ratio..but i think the minimum compression to do this was up around 12 or 13:1.
i've never actually DONE this before - but the theory is reasonably sound...just dont have the money right now to blow on a "this might work" kind of project.
as for the equation - er...i'll try and find you one. its not an easy thing to work out if memory serves.
twilightprotege is building on celica rods i think, high 1.5:1 rod ratio and needed 11:1 compression to do it.
bare in mind rod ratio is only PART of the problem with regards to revving the motor. It has a huge bearing on piston acceleration but piston acceleration alone isn't the be all and end all. you need to look at recipricating mass, mean piston speed, fuel burn speed, head flow, piston dwell and a range of other things - not saying you couldn't go to 9k , you may be able to go more...but don't think because you've bettered a honda in the rod ratio stakes you can better one in engine speed without risking your motor.
edit: this looks somewhat promising http://www.kb-silvolite.com/calc.php?action=comp - shows the difference between static and dynamic compression, and the effect rod length has on dynamic compression where static compression remains constant.
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12 or 13 compression in our climate is pretty crazy LW.
I realise theres more to it then piston acceleration however i found the new rod ratios to be pretty good. In regards to your build idea thatd be pretty expensive because as far as i know the 1.8 and 2 litre engines have differences relating to the way the cranks hooked up? However adapting k series rods wouldnt be cheap either.
Personally for a nice build SR20 rods would fit the bill and might be a bit easier to work in then 3SGTE rods. 1.58 rod ratio isnt to bad, installshield got to 8k on similiar rod ratio so in that regard MPS shouldnt be too much of an issue. recipricating mass however i failed to consider.
btw i found a formula for working out static compression i believe however i have nfi as to the unswept volume of a cylinder.
I realise theres more to it then piston acceleration however i found the new rod ratios to be pretty good. In regards to your build idea thatd be pretty expensive because as far as i know the 1.8 and 2 litre engines have differences relating to the way the cranks hooked up? However adapting k series rods wouldnt be cheap either.
Personally for a nice build SR20 rods would fit the bill and might be a bit easier to work in then 3SGTE rods. 1.58 rod ratio isnt to bad, installshield got to 8k on similiar rod ratio so in that regard MPS shouldnt be too much of an issue. recipricating mass however i failed to consider.
btw i found a formula for working out static compression i believe however i have nfi as to the unswept volume of a cylinder.
your mps will be far lower than installshield...rod ratio has nothing to do with mps - its totally stroke dependent...you have less stroke so you're home and hosed.
the sr20 rods work on the 2L crank - the big end width needs to be machined to fit. Theres plenty of room to lift the wrist pin on the pistons and get them in...on the 1.8L motor, i don't know....you would need to lift the wrist pin further and that could be problematic....
i like speed
Member
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- 2003.5 Mazdaspeed Protege
If one were to apply said knowledge to a turbo'd engine. Would you be better off making the stroke longer for more displacement or shorter for higher revs? I know there's more to it than that I'm just brainstorming.
Yah i just lack the knowledge to work out what sort of MPS are dangerous for our engines and what mine would be. So i used a reference point 
Im reading alot but im still finding black holes in what i know
Is that just due to the extra 1mm stroke or?
@i like speed
Theres a therad that covered this to some extent something like MAM stroker cranks. Installshield posted regarding this to a degree. It depends IMO with the current stroke you guys have going shorter stroke and having more revs. However the opposite can be applied that by increasing the stroke to say 94mm would still be fine for stock rev limit (as far as i can tell) however your capacity would increase to the area of about 2.1-2.2 litres greater capacity = more fuel which equals more boost in turn really. Thats my taking on the matter anyways.
Im reading alot but im still finding black holes in what i know
Is that just due to the extra 1mm stroke or?
@i like speed
Theres a therad that covered this to some extent something like MAM stroker cranks. Installshield posted regarding this to a degree. It depends IMO with the current stroke you guys have going shorter stroke and having more revs. However the opposite can be applied that by increasing the stroke to say 94mm would still be fine for stock rev limit (as far as i can tell) however your capacity would increase to the area of about 2.1-2.2 litres greater capacity = more fuel which equals more boost in turn really. Thats my taking on the matter anyways.
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BTW, here's the reason for **********:
http://www.mazdas247.com/forum/showthread.php?t=123700972
/threadjack
Edit: for the record, I found out about this about 5 minutes before posting it, stumbling upon it while searching for something. It's in the MSP section, but for some reason, it's nowhere else to be found. Odd considering few people know...many mods didn't know for crying out loud.
http://www.mazdas247.com/forum/showthread.php?t=123700972
/threadjack
Edit: for the record, I found out about this about 5 minutes before posting it, stumbling upon it while searching for something. It's in the MSP section, but for some reason, it's nowhere else to be found. Odd considering few people know...many mods didn't know for crying out loud.
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With regard to the FP, the deck height is 9.5mm lower than the FS, the compression ratio is 9.1:1 and iirc, I worked out the rod ratio to be 1.54:1. I can get the specs out of my engine manual if needed.
FWIW, my FP had Twiggy cams in for 49,000km and saw up to 7,750rpm every day for over a year. Peak power was still only at 6,500rpm, but it only lost about 2hp on the way to 7.5k. Very useful at the traffic lights. Engine still going ok at 184,000km, but I do wonder how much of it's life I've used up...
FWIW, my FP had Twiggy cams in for 49,000km and saw up to 7,750rpm every day for over a year. Peak power was still only at 6,500rpm, but it only lost about 2hp on the way to 7.5k. Very useful at the traffic lights. Engine still going ok at 184,000km, but I do wonder how much of it's life I've used up...
Stock oil pump, bearings, valve springs, in fact stock everything combined with my lack of engineering knowledge is the worry at 1,250rpm past redline! eg: could the flywheel or something let go and penetrate the cabin? I don't know.
I only briefly looked into going stupid NA, but didn't like the way the cost/benefit was going. I can't remember the details about wrist pins etc.
I only briefly looked into going stupid NA, but didn't like the way the cost/benefit was going. I can't remember the details about wrist pins etc.
- :
- 02' Protege ES (Gone)
16' Mazda 6 sport manual
naturally aspirated? but there arent many miata's on here.
