Supra71GTS_Ice Posted February 16, 2007 Share Posted February 16, 2007 Only when the rev limit increases, not simply through more power. -Ian Well people often make the mistake that the rod gave out when infact it was the rod bolt. But all i was trying to say was the stock pistons are much sturdier then the stock rods/rod bolts this has been stated before Pistons handle 1000+rwhp rods handle up to 850rwhp but the reocord for stock bottom end is 1017rwhp. But anything over 800rwhp is pushing it if you want it to last regards Ragnar Quote Link to comment Share on other sites More sharing options...
Wez Posted February 16, 2007 Share Posted February 16, 2007 then thats settled. thanks guys the the boost question...are my plans of running 1,6 bar (23 psi) on 99 RON out of the question or is it possible with good tuning? On a smallish turbo yeah. I am planning on 1.6bar with V-Power and I believe Paul Whiffin ran 1.6bar on stock internals for a long time using the turbo I have installed. As said before its all down to the mapping Quote Link to comment Share on other sites More sharing options...
Supra71GTS_Ice Posted February 16, 2007 Share Posted February 16, 2007 Doyou REALLY believe these 1000 RWHP claims?? That aside, it's trivial to make an engine last for 10 seconds on a drag strip, but I was taliking proper engine usage on a race track well i believe it when most of the guys on supraforums have posted up a dyno graph. For example one dyno-ed 1054rwhp with stock pistons tuned by Justin Nenni @ Tuning Concepts i´m not saying JE, CP or some other pistons are worse, offcourse they are better and much lighter. I was just pointing out that the rods/rod bolts are much weaker Quote Link to comment Share on other sites More sharing options...
csa Posted February 16, 2007 Author Share Posted February 16, 2007 would you classify my BL T67 as smallish then? On a smallish turbo yeah. I am planning on 1.6bar with V-Power and I believe Paul Whiffin ran 1.6bar on stock internals for a long time using the turbo I have installed. As said before its all down to the mapping Quote Link to comment Share on other sites More sharing options...
Supra71GTS_Ice Posted February 16, 2007 Share Posted February 16, 2007 would you classify my BL T67 as smallish then? well maybe smallish/mid range i know P-Björck in Sweden is running 27 psi on V-Power with a 72mm turbo. But i would definately not recommend it. I have a 71mm turbo and i´m running 19 psi on V-power but why don´t you just get a Meth/water Injection kit to be safe ? Quote Link to comment Share on other sites More sharing options...
csa Posted February 16, 2007 Author Share Posted February 16, 2007 hmm...would this settle the score? whats the cost of something like that, and whats the "rocket science level" of installing it? but why don´t you just get a Meth/water Injection kit to be safe ? Quote Link to comment Share on other sites More sharing options...
Ian C Posted February 16, 2007 Share Posted February 16, 2007 Regarding the rod bolts being 'weak' - the harshest loadings on a rod bolt are at TDC on the exhaust stroke, where the cylinder is producing no power at all, and this loading increases massively with higher revs (I think it's that square law that I can't remember the name of). These forces are much much higher than anything produced by the in-cylinder pressures caused by power generation, and those are compressive loads anyway. So the rod caps fret as the bolts stretch and snap. Yep, they give way first but if you don't rev past 6800rpm or maybe even 7200rpm then they should last as long as a stock motor would. So power has nothing to do with the rod bolt failures, only higher revs be they power producing or not. I think calling them 'weak' is a bit of an insult to them heh The 'uprated' ones are an interesting proposition as someone who knows far too much about this sort of thing says it's all about the clamping force rather than the material type. If your rod bolts need to be tightened up to x ft/lbs then they can be made of cheese or of Hardium, as long as they can be tightened to that clamping force. If you want to rev higher and stop fretting (where the rod cap comes away from the rod due to the tension forces overcoming the bolt clamping forces) then you have to physically do them up tighter. This can then ovalise the conrod big end bore. Anyway. The good news is that a good well maintained stock bottom end can see enough power to make most people happy. I wouldn't go much past 600bhp, but then who needs to If it's a daily driver and used on the roads that is. I'm not arguing regarding how good the pistons are. I know of some monsters that use stock pistons and I've only ever heard of them letting go due to detonation. -Ian Quote Link to comment Share on other sites More sharing options...
Wez Posted February 16, 2007 Share Posted February 16, 2007 Great post Quote Link to comment Share on other sites More sharing options...
Supra71GTS_Ice Posted February 16, 2007 Share Posted February 16, 2007 Regarding the rod bolts being 'weak' - the harshest loadings on a rod bolt are at TDC on the exhaust stroke, where the cylinder is producing no power at all, and this loading increases massively with higher revs (I think it's that square law that I can't remember the name of). These forces are much much higher than anything produced by the in-cylinder pressures caused by power generation, and those are compressive loads anyway. So the rod caps fret as the bolts stretch and snap. Yep, they give way first but if you don't rev past 6800rpm or maybe even 7200rpm then they should last as long as a stock motor would. So power has nothing to do with the rod bolt failures, only higher revs be they power producing or not. I think calling them 'weak' is a bit of an insult to them heh The 'uprated' ones are an interesting proposition as someone who knows far too much about this sort of thing says it's all about the clamping force rather than the material type. If your rob bolts need to be tightened up to x ft/lbs then they can be made of cheese or of Hardium, as long as they can be tightened to that clamping force. If you want to rev higher and stop fretting (where the rod cap comes away from the rod due to the tension forces overcoming the bolt clamping forces) then you have to physically do them up tighter. This can then ovalise the conrod big end bore. Anyway. The good news is that a good well maintained stock bottom end can see enough power to make most people happy. I wouldn't go much past 600bhp, but then who needs to If it's a daily driver and used on the roads that is. I'm not arguing regarding how good the pistons are. I know of some monsters that use stock pistons and I've only ever heard of them letting go due to detonation. -Ian Good info i was in a way only talking about when you are going over 800rwhp on stock bottom end and most that are over 800rwhp have different cams and upgraded springs and retainers, 264 , 272 or 280 or something like that. And have the rev limiter to 8000rpm or more. And was kinda stating in those condisitions the rod bolts/rods give out not the pistons(in high horsepower supras with a stock bottom end). and just for the record, my rev limiter is set to 8200rpm i have crower springs and retainers and HKS 264 cams. And hopefully i will see 800+rwhp this summer on race gas Ragnar Quote Link to comment Share on other sites More sharing options...
fastisnice Posted February 16, 2007 Share Posted February 16, 2007 First of all, I would advice you to go for a 71 instead of 67, you can make so much more power out of it with the right peripherals. Pistons are good enough for 750-800bhp, rod bolts are the weakest link but this depends on your rev limiter, i got mine @ 8,200 but thats with titanium springs and retainers and i do have an HKS head gasket(stock size though-no point going thicker, u'll only get more lag as you will lower the compression) and arp bolts. I do have a build head as well, you gain a lot more power out of it, we saw on the dyno 70bhp more! and much better flow. It dyno'd @ 1.7 = 720bhp but since that time i've done few more bits to it and i still have the NOS to set up(only as antilag). A good stock supra engine can take 750-780bhp all day long. oh and ive been running mine for a year on that setup.It doesnt even use oil!!. Its the peripherals you have to worry about!(pumps, various pulleys etc). I have 2 setups on the motec 1.5 & 1.7, 1.8 is easily done as well on 99 pump gas but for me there is no point for street as its too much power as it is. So go for 1.7 but make sure your tuner is top of the top..thats all it matters. Quote Link to comment Share on other sites More sharing options...
csa Posted February 16, 2007 Author Share Posted February 16, 2007 changing turbo won't be a solution right now as I am fully satisfied with 600-700bhp, and that's really the range I'de like to be in Quote Link to comment Share on other sites More sharing options...
fastisnice Posted February 16, 2007 Share Posted February 16, 2007 emm. There is no way you get 700 out of a 67..Don't believe american figures there are a load of crap..take 100bhp off what they say.I would say maximum 600 thats if you get lots of other work done to it and run really high boost. Someone i know got [email protected] with a P67 1.6-1.7 i super safe go for it Quote Link to comment Share on other sites More sharing options...
csa Posted February 16, 2007 Author Share Posted February 16, 2007 okay..well I had it dynoed with my current MAP ecu setup using a vert crappy homebrew map and 1.3 boost...it made 405 rwhp... Quote Link to comment Share on other sites More sharing options...
Paul Whiffin Posted February 18, 2007 Share Posted February 18, 2007 On a smallish turbo yeah. I am planning on 1.6bar with V-Power and I believe Paul Whiffin ran 1.6bar on stock internals for a long time using the turbo I have installed. As said before its all down to the mapping I ran 1.9 bar mate and that was a stock bottom end, no problems at all and the engine looked mint when I took it apart. I ran 1.5 bar for track use though, sustained use at 1.9 bar might be a problem, depends on your luck I suppose! Quote Link to comment Share on other sites More sharing options...
Wez Posted February 18, 2007 Share Posted February 18, 2007 Paul, I know you keep trying to get me to turn it up I am still getting use to it at 1.4bar Quote Link to comment Share on other sites More sharing options...
csa Posted February 19, 2007 Author Share Posted February 19, 2007 sounds like I'm afterall aiming at 1.6 and then... Quote Link to comment Share on other sites More sharing options...
Gamer Posted February 19, 2007 Share Posted February 19, 2007 Paul, I know you keep trying to get me to turn it up I am still getting use to it at 1.4bar Did you get a free skirt with that turbo kit mate Quote Link to comment Share on other sites More sharing options...
Wez Posted February 19, 2007 Share Posted February 19, 2007 Did you get a free skirt with that turbo kit mate Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 19, 2007 Share Posted February 19, 2007 Paul, I know you keep trying to get me to turn it up I am still getting use to it at 1.4bar It goes REALLY well. A credit to you. It now has enough grunt to warrant dome better suspension, or at least some fiddling with the settings. I'll have a look and think about it. There's not enough rebound control on the front dampers. Quote Link to comment Share on other sites More sharing options...
Wez Posted February 19, 2007 Share Posted February 19, 2007 It goes REALLY well. A credit to you. It now has enough grunt to warrant dome better suspension, or at least some fiddling with the settings. I'll have a look and think about it. There's not enough rebound control on the front dampers. Thanks Chris Quote Link to comment Share on other sites More sharing options...
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