Guest Anonymous Posted October 30, 2001 Share Posted October 30, 2001 What kind of (safe) redline could one except on an L28 turbo with arp bolts and race prepped rods? I drove my friends S2000 the other day and that things revs to 9000rpm, its unbeleivable, I'm sure you can't take an L6 that high but I want to build a motor that really revs and I dont want to worry about throwing a rod or something. Can you build a turbo L6 to make power to around 7500rpm(or more?). Would the cam I'd need to do this just be to much to be streetable? I'm not terribly concerned with low end torque but this would car would probably be a daily driver. Quote Link to comment Share on other sites More sharing options...
fl327 Posted October 30, 2001 Share Posted October 30, 2001 i think the highest you can go, even built up well, is 7k, and believe me, most inline guyz dont rev that high, the only z i know that revs like that has over 25k in motor and turbo alone.... this motor wasnt built for revs, most straight sixes dont rev that high, reasonable build i think 6k redline, and thats plenty... Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted October 30, 2001 Share Posted October 30, 2001 Not true, the L can rev to 9K if properly built, but most race apps see about 8K. The redline on my stroker is 7200rpm with no problem or worries. I would say 7K is a good pratical limit for most apps and unless you have the car cam'd for the higher revs you don't get much out of it. Quote Link to comment Share on other sites More sharing options...
DavyZ Posted October 30, 2001 Share Posted October 30, 2001 Datto, who posts occasionally here, sees 8K on a fairly regular basis. I always thought that was way high, but I guess not. Davy Quote Link to comment Share on other sites More sharing options...
fl327 Posted October 30, 2001 Share Posted October 30, 2001 whoa, so what does it take to rev a straight six that high on pump gas, my l28 has no juice after 5500 or so... Quote Link to comment Share on other sites More sharing options...
KAZU Posted October 30, 2001 Share Posted October 30, 2001 The race-prepared normal crank would help a little but I rather go the ATI Super Damper with normal crank. Race crank with normal damper does'nt make sense but I don't know it is legal at the competition of SCCA or others. With the ATI damper, the mass will be located more close to the front cover and the polley will be located on the front side of the damper. This design would be better than that of the Nissan Motorsports which has the pulley on the backside of the damper. Kazu Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted October 31, 2001 Share Posted October 31, 2001 Does not matter what anyone thinks a L28 can be revved up to. Bottom line is a L28T with the stock cam does not need to go pass 6500 and is probably already losing power at that point. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted October 31, 2001 Share Posted October 31, 2001 I don't see the attraction of rev'ing it that high anyway unless your racing it and have rules on the type of induction etc, or you just dig hearing it whine like a banshee. A Vtec was designed to run that high. Honda was good at it, they've had practice since the 60's of running small 4's from 16,000 to 20,000 RPM's in the GP bikes. Imagine a 250cc 6cyl 4 stroke turning 16,000 revs, the pistons are about the size of a half dollar and the stroke is hella short, well lets just say the pistons sort of vibrate rather than stroke up or down . Obviously from the experienced L6's guys on here, its possible to spin it that high, but on a street car? You could probably build so much sick power under 6K with alot of boost and it will be much nicer to cruise with (IMHO) and you won't be rebuilding it every year. Just an opinion mind you, as everyone's idea of a 'streetable' setup is different. Regards, Lone Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 31, 2001 Share Posted October 31, 2001 I'd love to hear what kind of duration, valve spring seat and open pressures you guys run to rev AND MAKE POWER at 8 and 9000 rpm! That CAN'T be very streetable, but maybe that doesn't matter to some people. I realize that OHC the valve train is lighter, but are the valve spring pressures light enough for a 9000 rpm capable spring such that it doesn't wear the cam out in 5000 miles? If it revs to 8000 or 9000 rpm, AND MAKES POWER THERE, where's the torque peak? Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted October 31, 2001 Share Posted October 31, 2001 Let me be clear about what I have posted. It was my understanding the question asked was, "how high can the L be revved?" It is true the L4 can outspin the L6, but the L6 can be made to spin to 9K. As I have been told there are 2 distinct rpm points at which crank resonance appears, but I cannot remember what rpm points those were. My info is based on talks with Don Potter and Jim(Sunbelt). There is a difference between asking what is the rev potential and the powerband for a certain engine setup. Lifts in the .550+ range and high durations would be needed to benefit from making peak power so high. When I dynoed Joel's turbo L6 it still made 330hp@wheels at 6800rpm before I shut it off. It all depends on the mods you have done to your motor and the application you are intending the motor for. Quote Link to comment Share on other sites More sharing options...
KAZU Posted October 31, 2001 Share Posted October 31, 2001 This might be off topic, pparaska, this is the typical power curve of MILD L3.1 (non turbo) in Japan: 260 RWP @ 6,500rpm. The cam has 300 duration but low .34 lift so they call it a mild cam and the car is very streetable with 100 RON gas. Even though its low lift, the valve springs of this engine were too stiff so the valve seats were eaten... There are more radical L3.1s on street cars in that country. LD28 crank is believed to be broken just above 8,500 rpm. Dragrace guys do no preparation of the crank and just replace it as a pair of socks when it is broken. [ October 30, 2001: Message edited by: KAZU ] [ October 30, 2001: Message edited by: KAZU ] Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 31, 2001 Share Posted October 31, 2001 Thanks, that's kind of what I figured on the valve spring pressures needed. Kinda dead until about 3500 rpm - fine for drag racing IMO, but I wouldn't want it on the street. Thanks for posting that! Quote Link to comment Share on other sites More sharing options...
KAZU Posted October 31, 2001 Share Posted October 31, 2001 I've heard that it has a lot of torque at low range. It wasn't WOT until 3,500 rpm, IMO. Kazu Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 31, 2001 Share Posted October 31, 2001 Cool. I just thought that when people did dyno runs they typically hammered it all the way. I wonder what the Z31 motor would put out for torque at say 2500 rpm if fully spooled and loaded? Quote Link to comment Share on other sites More sharing options...
TimZ Posted October 31, 2001 Share Posted October 31, 2001 quote: Originally posted by 240Z Turbo: Not true, the L can rev to 9K if properly built, Everything that I have read points to a harmonic crankshaft resonance problem at around 8k, which can result in crankshaft breakage. This usually happens only when the engine spends large amounts of time at that rpm (like endurance racing), but the problem is there. As such, I'd keep the redline below 7500, personally. Really, with a turbo, it's easier and more driveable to make your power at lower rpm, anyway. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted October 31, 2001 Share Posted October 31, 2001 I was under that impression to, they measure the length of time it takes to spin up a 4000 lb drum to a specific RPM or something. I know the high HP cars can spin that dude up quick. At least that was my understanding how a roller dyno works. Regards, Lone Quote Link to comment Share on other sites More sharing options...
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