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#1
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Decisions, decisions...some advice I'm getting says stick with OEM valve springs because the racing springs create excessive wear on the cams / valve train for a street / DE car. Don't want to have to rebuild every couple of seasons. Other advice says the wear's not a problem and you really want the additional overrev protection the the racing springs offer.
So, as always, I have no clue. Any opinions (re: the springs, not whether or not I have a clue)? Preferably ones with experience or good anecdotal info. Thanks! |
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#2
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What rpm are you looking to redline at? I'm not up on the spec's of your motor Jim, but the operating rpm and redline should dictate the need for stiffer springs.
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78 SC, the 'Red Car' |
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#3
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I'm building essentially a classic 2.7RS, but with the CR bumped a bit. I think their redline is 7100 or 7300, I forget right now. This implies OEM springs; however, I have had some notable engine builders try to steer me towards the racing springs for some insurance against those money shifts.
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#4
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From what I have heard/read it would be wise to use the race springs. The heavier spring rate is needed due to the ramp rate on an S or hotter cam. The heavier spring just keeps the valve where its supposed to be. You don't want float at 7300 rpm and since this motor will see lots of track time... well you get the idea.
If you update the springs you can always change the cam specs a bit (mod-S) and grab quite a bit of HP as well as rpm. Off track drivability may suffer a bit though. When the 32.SS starts to come together I will be updating the springs. I will have a 7K redline as set by my cam choice and displacement. The valve train should be good for about 1500 more in the event of a miss shift. The problem with this logic is that a forced mis-shift will spin the motor about 10-12K rpm and there is no hope. I guess I need to call Wevo to rectify this problem.
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Jamie 71 911t SWT - stock and original 71 911 ST replica - HMM, Not so stock and definitely not original. 75 914 soon-to-be-WRX-Powered- GRM $2010 Challenge car. |
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#5
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Never read anything about Porsche springs & valve float! Like Jamie says; missed shift – don’t matter! New stock springs or new hardened cam billets w/racing springs & valve collars ($$$$). Ask yourself “what did the factory use”?
Go ahead & plan on racing springs for now, you’ll change your mind 4 times between now & then anyway
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David I hope to arrive to my death, late, in love, and a little drunk! Just because I don't care doesn't mean I don't understand... Homer Simpson "That's what's keeping me out of F1.... Too much mental maturity...." N0tt0n Some cause happiness wherever they go; others whenever they go. CHAOS, PANIC, AND DISORDER my work here is done... Live without pretending, Love without depending, Listen without defending, Speak without offending |
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#6
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Quote:
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Chris M 1985 911 Carrera with a couple cosmetic only mods 2006 E90 330i 1999 E46 328i |
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#7
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#8
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Check into Assco springs. They have both a "sport" and a "Race" spring. I used their Sport spring with Ti retainers to lighten the load. Overkill? Yea probably, just check out my muffler, I'm all about overkill.
Along with keeping the valve were it should be, It'll allow you to hold a gear a little longer for a pass. This will be good for the inevitable Dorki Drag Race after you get a point by on the front straight. (BW911)
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Ted Thomas 2003 325xi Payback's a bitch. Stand the f@#k by! |
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#9
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Quote:
This is what we run in the SSPI cars. Here is a link: AAsco Performance Jason |
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