Wez Posted October 24, 2007 Share Posted October 24, 2007 Any famous last words for us all Wez? My rev limit is writing cheques my rod bolts cant cash The next time I am in the car it will be reduced thats for sure Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted October 24, 2007 Share Posted October 24, 2007 7200 is plenty on stock rods and bolts. I'd only risk 7500 with ARP bolts and a repair fund that's set aside! It's a long stroker, and the pistons are no lightweights. Quote Link to comment Share on other sites More sharing options...
Ian C Posted October 24, 2007 Share Posted October 24, 2007 Ian do you cut ign and fuel at the same time or one after the other? I just have the EMU bypassing the stock fuel cut, well, moving it up a bit. No ignition related cut. Ign cut is good for the pops and the bangs I imagine I figure 7200rpm is safe as that's what the VVTi revs to - on the same short motor. And it can make use of it with the variable intake cam, unlike the non-vvti which coughs it's lungs up at 5500rpm. -Ian Quote Link to comment Share on other sites More sharing options...
Wez Posted October 25, 2007 Share Posted October 25, 2007 Ign cut is good for the pops and the bangs I imagine Quote Link to comment Share on other sites More sharing options...
Guest whatthe Posted November 8, 2007 Share Posted November 8, 2007 7200 is plenty on stock rods and bolts. I'd only risk 7500 with ARP bolts and a repair fund that's set aside! It's a long stroker, and the pistons are no lightweights. Hello Chris, this thread came up on another forum, and it is really quite contradictory to my experience. I understand that you are highly regarded on the UK, so before I get into anything else, basically my questions are how many time have you had the 2JZ spitting rods at 7400+rpms? and was it all on the 280hp market Supras? I'm asking to basically find out if there is a difference between the North American 2JZ and say my JDM market 2JZ. My understanding is that with a proper turbo the powerband is big enough to not require any more revs, not that it will throw a rod at 7500rpms... because I just haven't seen it. As for examples from my side.... I hate to bring up Regs name as he's plastered around enough over here, but Reg Reimer at RCTS in Canada has been regarded as a Supra guru since the 90s. Having made software for the 2JZ that even "safely" raises the rev-limit to 7500rpms. http://suprasonic.org/sonictech/techtom/ This is backed up by many customers who have not had a failure that I'm aware of, as well as some serious competitive road racing against the biggest names and factory backed teams out there. The car was driven from Canada and road raced in a circuit of tracks around the United States (One-Lap of America). 5000km round trip, no pit crew, drive the car between stages (not trailer). Road race configuration somewhere in the high 10s@130mph or so (they also had a drag day). Running 600hp, 7500+ rpm limit. This wasn't just done for one year, it was done for 1996, 1997, 1998, 1999, 2000. No aftermarket engine bolts/pieces were used. Combine that with a few other examples... http://www.to4r.com/member.php?show=marcus.frost http://www.t04r.com/member.php?show=john.firth And then some more extreme examples with upgraded head and stock blocks revving over 8000rpms http://www.t04r.com/member.php?show=son.nguyen http://www.t04r.com/media/peteribrahim_dyno.jpg I'm just wondering what is different and what has convinced you that a repair fund is needed. 1000rpms difference with just a modified heads and a stock bottom end is still a pretty big difference. (I really don't know if the other guys are the best examples, I only know Reg personally) Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted November 8, 2007 Share Posted November 8, 2007 AFAIK the bottom ends are the same. Despite the wondrous claims of 1000 BHP on stock bottom ends, the "bulletproof" nature of the engines, blah blah, from across the sea I personally would not be happy revving such a long stroke engine so far above the makers set RPM limit without mods to strengthen the reciprocating parts. Whatever the findings of your friend it's my reputation on the line if a customer engine throws a rod, so I err on the side of caution, and assume Toyota didn't set a rev limit 1000 RPM lower than necessary. As you say, there's no NEED to rev a mild cammed turbo engine high, anyway. Quote Link to comment Share on other sites More sharing options...
Daston Posted November 8, 2007 Share Posted November 8, 2007 talking about limiters I nailed it the other night and it got to 6k as normal but then seemed to find it real hard to go any more, I know I should have changed before this but I hesitated when it didnt seam to climb any further Quote Link to comment Share on other sites More sharing options...
Mike B Posted November 8, 2007 Share Posted November 8, 2007 I use 7.5 too, but with a built bottom end. I shall try and keep it under 7 just to be civil after reading this. Quote Link to comment Share on other sites More sharing options...
Guest whatthe Posted November 8, 2007 Share Posted November 8, 2007 AFAIK the bottom ends are the same. Despite the wondrous claims of 1000 BHP on stock bottom ends, the "bulletproof" nature of the engines, blah blah, from across the sea I personally would not be happy revving such a long stroke engine so far above the makers set RPM limit without mods to strengthen the reciprocating parts. Whatever the findings of your friend it's my reputation on the line if a customer engine throws a rod, so I err on the side of caution, and assume Toyota didn't set a rev limit 1000 RPM lower than necessary. As you say, there's no NEED to rev a mild cammed turbo engine high, anyway. I can appreciate being conservative, and I know of at least one engine builder with the motto that RPM kills motors (explained quite quickly with math). But, I'm just wondering about the chucking a rod comment. Is this based on having destroyed the bottom ends on a series of 2JZ engines at 7500rpms? If so, I'd like to know more details. My friend is known for tuning and building reliable cars. They have to be in order to be competitive in an event like that. The first year the Supras came out, he didn't assume that the engine would handle more than 450whp. Many years of racing and testing later, and you won't see him pushing 1000hp from his car on daily basis any time soon, but he also won't say it will blow up from something he hasn't tested. Quote Link to comment Share on other sites More sharing options...
Lee P Posted November 8, 2007 Share Posted November 8, 2007 I get advise from a race team in america a fair bit and this is what they told me about the stock engine. "I would limit the rear wheel hp to 600 with stock bottom end. We have run stock motors to 750 wheel hp, but the rods kept failing during wide open throttle runs in 6th gear even with a good tune up." I personly wouldn't rev the stock engine past 7500 rpm and uprated springs would probly be a good idea for that rpm. My 2 pence Quote Link to comment Share on other sites More sharing options...
suprafan72 Posted November 8, 2007 Share Posted November 8, 2007 Would you believe Dan Turner originally set mine to 8,200rpm.. how nice!!! NOT!!! Mines back to 7000 now Quote Link to comment Share on other sites More sharing options...
TLicense Posted November 8, 2007 Share Posted November 8, 2007 8200. LOL you got to hand it to him, he's definitely an optimist! Quote Link to comment Share on other sites More sharing options...
dandan Posted November 8, 2007 Share Posted November 8, 2007 Would you believe Dan Turner originally set mine to 8,200rpm.. Yes I would. Quote Link to comment Share on other sites More sharing options...
Lee P Posted November 8, 2007 Share Posted November 8, 2007 Thats crazy! How long ago was that? He's very conservative now. Would you believe Dan Turner originally set mine to 8,200rpm.. how nice!!! NOT!!! Mines back to 7000 now Quote Link to comment Share on other sites More sharing options...
suprafan72 Posted November 9, 2007 Share Posted November 9, 2007 Thats crazy! How long ago was that? He's very conservative now. 5 months ago.. I think with the knocks hes had recently he won't be doing much more than crying soon.!! Quote Link to comment Share on other sites More sharing options...
Ian C Posted November 9, 2007 Share Posted November 9, 2007 talking about limiters I nailed it the other night and it got to 6k as normal but then seemed to find it real hard to go any more, I know I should have changed before this but I hesitated when it didnt seam to climb any further I imagine you've got stock cams? -Ian Quote Link to comment Share on other sites More sharing options...
Daston Posted November 9, 2007 Share Posted November 9, 2007 yes all internals are stock as far as I know Quote Link to comment Share on other sites More sharing options...
Ian C Posted November 9, 2007 Share Posted November 9, 2007 yes all internals are stock as far as I know Stock cams choke up at about 5500rpm so you definitely get a dropoff of power above that, so much so that it's noticeable - as you've found out. Anything 256/264 or 264/264 cam-wise and you'll find it pulls strong to the rev limiter -Ian Quote Link to comment Share on other sites More sharing options...
Wez Posted November 9, 2007 Share Posted November 9, 2007 Anything 256/264 or 264/264 cam-wise and you'll find it pulls strong to the rev limiter And beyond Quote Link to comment Share on other sites More sharing options...
Digsy Posted November 9, 2007 Share Posted November 9, 2007 I can appreciate being conservative, and I know of at least one engine builder with the motto that RPM kills motors (explained quite quickly with math). But, I'm just wondering about the chucking a rod comment. Is this based on having destroyed the bottom ends on a series of 2JZ engines at 7500rpms? If so, I'd like to know more details. My friend is known for tuning and building reliable cars. They have to be in order to be competitive in an event like that. The first year the Supras came out, he didn't assume that the engine would handle more than 450whp. Many years of racing and testing later, and you won't see him pushing 1000hp from his car on daily basis any time soon, but he also won't say it will blow up from something he hasn't tested. The short answer is that I don't think anyone knows for sure what the bottom end rev limit actually is with regards to a straight mechanical failure. I would assume that CW is giving advise based on his best practises, but I doubt he (or anyone else) has put a 2JZ into high RPMs specifically to see when a rod will fail. As Chris says, its his reputation that is on the line and stuff that gets posted in forums has a tendancy to become fact very quickly. If I were him I wouldn't fancy making a glib claim that the stock bottom end is good for more than stock RPM and then have someone prove him wrong, to entirely their detriment. Chris builds race engines for a living, and I guess has thrown his fair share of rods in his time, albeit not "in laboratory conditons" He knows that higher RPMs can kill rods on engines with a small L/R ratio (long strokers), so he recommends uprating the reciprocating parts if you want to go there. Your mate has some experience that suggests 7500RPM may still be safe on stock internals, which is all fine, although its a sample size of one. Good for him for being prepared to try it out, though. Personally, I know that inertia loads increase by the square of the change in engine speed, so you won't have to go too far before you are going seriously beyond what Toyota will have considered in their design. Unfortunately, without access to simulation codes or an actual test engine that someone is willing to sacrifice, there will never be a definitive answer. Quote Link to comment Share on other sites More sharing options...
Lee P Posted November 9, 2007 Share Posted November 9, 2007 5 months ago.. I think with the knocks hes had recently he won't be doing much more than crying soon.!! He mapped mine end of July, I think it wasnt long after yours was there because he mentioned it. He would not take mine past 7800 rpm and Ive got a built engine! Quote Link to comment Share on other sites More sharing options...
Terminator Posted November 9, 2007 Share Posted November 9, 2007 So a built motor balanced to 15,000 with an 11,000 rev limit is not good? Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted November 9, 2007 Share Posted November 9, 2007 I have indeed had experience of plenty of rod failures, my own Skyline engine broke an ARP rod bolt this year. Too many revs (1000 over the makers limit, but with decent bolts on a balanced bottom end) and too few rebuilds. I can tolerate my own engines letting go, customer road engines i try and be more conservative with, but even with a sensible RPM rev limiter setting you can't cater for someone sticking it in second at 100 MPH, you just do your best given the build of the engine and the perceived acceptability of an engine failure for them. Quote Link to comment Share on other sites More sharing options...
Terminator Posted November 9, 2007 Share Posted November 9, 2007 Ouch not a pretty sight. Which RB engine Chris? Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted November 9, 2007 Share Posted November 9, 2007 RB25DET The inlet manifold is OK.... Quote Link to comment Share on other sites More sharing options...
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