How safe is 7000rpm on the FS with stock internals?

[LordWorm]

Hey all,

about a month out from microtech stuff now - wanting to bump the redline up a bit and squeeze a bit more out of the car for the track. I know Twilightprotege runs 7000rpm on stock internals, so I'm wondering just how safe this is?

Is it a case of very safe, no hassles, or pot luck..might work on one car, might grenade on another?

 

[vindication]

as long as the tune is good. but I wouldn't keep it up there for too long or do it quite often. even on forged internals it's been known to blow at high rpm. but I guess it depends on tune.

 

[LordWorm]

as long as the tune is good. but I wouldn't keep it up there for too long or do it quite often. even on forged internals it's been known to blow at high rpm. but I guess it depends on tune.

Tune will be as safe as possible at such a high RPM... but it is afterall only 500rpm over stock.....

Obviously i wont sustain 7000rpm, and rarely if ever push it that far on the street...purely for track work...oil change etc immediatly after reving its ring out like that too.

I've had it there once on a downchange with no ill effects....but downchange is a little different to thrashing it out to that speed.

 

[vindication]

I also suggest getting the AWR oilpan. with that high rpm you might wanna have oil be able to get up there and not slosh around in our crappy oil pans and then get starved.

 

[LordWorm]

I also suggest getting the AWR oilpan. with that high rpm you might wanna have oil be able to get up there and not slosh around in our crappy oil pans and then get starved.

going dry sump... is 7000 high? i mean, is it out of hte ordinary? tis only 500rpm over stock...its not like i'm spinning it to 8 or 9....

 

[vindication]

depends. these motors are like women, you never know when they are going to **** you over. what could be fine one time will not be fine another time or for another person. I dont think it's high but our twig-like rods may give out after some use. Ask installshield or twilight, they should be able to tell you better.

 

[LordWorm]

depends. these motors are like women, you never know when they are going to **** you over. what could be fine one time will not be fine another time or for another person. I dont think it's high but our twig-like rods may give out after some use. Ask installshield or twilight, they should be able to tell you better.

I work with Twilight and yeh... no definative answer really ... i.e. "i'll tune it to run to 7k but if it blows up i didnt do it "... hahaha...

i plan to rebuild eventually and go completely stupid with it... but cant rebuild if theres a hole in the block where a rod punched through.

 

[Gen1GT]

Yeah, I think if you make fuel/ignition cut right at 7000, you may be able to get away with it in short bursts, but I would be bouncing off a 7000RPM limit during autocross. People blow the stock engine during cornering, so you need to be careful.

 

[LordWorm]

Yeah, I think if you make fuel/ignition cut right at 7000, you may be able to get away with it in short bursts, but I would be bouncing off a 7000RPM limit during autocross. People blow the stock engine during cornering, so you need to be careful.

i'm a straight line racer she dun go round corners

i might hedge my bets and set the soft cut at 6800 and hard at 7000
even if i push it at 6800 its not going to push 200rpm past the soft cut in a fit...

 

[Focus]

I know Twilightprotege runs 7000rpm on stock internals, so I'm wondering just how safe this is?

Is it a case of very safe, no hassles, or pot luck..might work on one car, might grenade on another?

The real major issue to look at would be valve float. Do a little head work and you should be able to hold 7000 RPM easily. The only company that sells Valve Spring ( that I know of) is eibach...

 

[LordWorm]

The real major issue to look at would be valve float. Do a little head work and you should be able to hold 7000 RPM easily. The only company that sells Valve Spring ( that I know of) is eibach...

theres a place here that does custom springs... might work out cheaper than eibach... twiggy is running stock springs tho... spose if my plans ever come to life i'll need to do headwork anywya...might as well...

if you dont mind me asking, whats your "hold 7000 RPM easily" based on? interested to know how conclusions like this are arrived at... cheers

 

[Focus]

theres a place here that does custom springs... might work out cheaper than eibach... twiggy is running stock springs tho... spose if my plans ever come to life i'll need to do headwork anywya...might as well...

if you dont mind me asking, whats your "hold 7000 RPM easily" based on? interested to know how conclusions like this are arrived at... cheers

Trial and error mostly. Proper balancing, valvetrain and Engine management, you will be able to sustain 7000 RPM without problems.

 

[LordWorm]

Trial and error mostly. Proper balancing, valvetrain and Engine management, you will be able to sustain 7000 RPM without problems.

fair enough

i guess what i'm after is a definative 'you are not going to drop a rod so just do it'

but noones gunna give that to me are they? hahaha

 

[Focus]

fair enough

i guess what i'm after is a definative 'you are not going to drop a rod so just do it'

but noones gunna give that to me are they? hahaha

Not with the fisher price rods in the protege !!

 

[LordWorm]

ok so you're saying that it should hold 7000 but dont count on it?

where would you consider the max safe point be? or is 6500 about it?

 

[Focus]

ok so you're saying that it should hold 7000 but dont count on it?

where would you consider the max safe point be? or is 6500 about it?

Is there really a safe point? The motor can let go just as easily at 5000 RPM, or it may last forever running it at 8000 RPM... That is kinda a loaded question !!

 

[LordWorm]

Is there really a safe point? The motor can let go just as easily at 5000 RPM, or it may last forever running it at 8000 RPM... That is kinda a loaded question !!

well, one would hope that anything UNDER the factory rev limit has been extensively tested by some boffin at mazda HQ

considering the lengths installshield2 went to to get his up over the 8k mark i dont think the stockos would do it....

rather then get a definative answer...how about this... am i LIKELY to break stuff at 7000rpm and where am i LIKELY to be safe if 7k isnt safe?

 

[TheMAN]

7000rpm is NO problem considering the FS-ZE redlines at 7000 and rev limits at 7300rpm... the rods and crank in the FS-ZE are the same, and so is the valvetrain (except for the intake cam, big deal)

 

[fc3sboy]

7000 rpm

i have 2 blocks sitting in my shop with rather large holes in them due to 7000-7300 rpm runs. the problem with them is the conecting rod bolts failed. the bolts broke in half sending the rod caps out the side of the block on one and threw the brace on the other then threw the block, that one was quit impressive lol. anyways i would highly recomend a set of good rods or atleast stud the damn conecting rods with arp studs.


randy

 

[TheMAN]

if those engines threw a rod because they were running a stock ECU then that's to be expected because when you hit the rev limiter, you run lean and all sorts of shock forces are put into the bottom end from having the combustion happening off and on again over and over