csa Posted February 14, 2007 Share Posted February 14, 2007 Had a talk with my tuner the other day, and he told me that he wouldn't recommend more than max 21 psi (1.45 bar) when running on stock headgasket and bolts. is this true? had really hoped to make at least 23 psi (1,6 bar) Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 14, 2007 Share Posted February 14, 2007 The stock gasket is a multi layer steel shim gasket. So are the HKS, Trust and Apexi ones. The only gasket I feel is (maybe) slightly better is the very expensive closed bead ones Cometic did as special order short run. I think they have all gone, anyway. I'd be 100% happy running 2 bar on a stock gasket. Link to comment Share on other sites More sharing options...
csa Posted February 14, 2007 Author Share Posted February 14, 2007 hmm...guess my dear tuner is sandbagging quite a bit then. well since we're at it. what would you recommend as max pressure with my setup, running on 99 pump (yes Shell has blessed us swedes!) BL T67 kit BL fuelkit with 1000cc Fcon V pro uprated plugs, but no DLI Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 14, 2007 Share Posted February 14, 2007 Impossible to say, depends on too many factors, just map it carefully and keep upping the boost watching EGT's and for det. Then drop it down a bit to allow for climate and fuel changes. IMO mapping on anything other than an engine dyno is risky, if you want to control everything properly, and get the last bit out of it. Link to comment Share on other sites More sharing options...
Supra-Dupra Posted February 14, 2007 Share Posted February 14, 2007 hmmm why is that then chris? my friend got his old car mapped out on the open road, wouldnt this be better as its more "real life" condition more so than a simulator? Link to comment Share on other sites More sharing options...
csa Posted February 14, 2007 Author Share Posted February 14, 2007 well unfortunately I can't afford the luxury of an engine dyno. The car will be mapped on the inhouse dyno, by a certified HKS prodealer. I guess time will tell how much boost the old girl will take then. Link to comment Share on other sites More sharing options...
SimonB Posted February 14, 2007 Share Posted February 14, 2007 hmmm why is that then chris? my friend got his old car mapped out on the open road, wouldnt this be better as its more "real life" condition more so than a simulator? In a word, no. The best way is on a dyno, you set the dyno to hold a particuar rpm, which it does regardless of the engine load by varying the resistance. Then you go through the different loads and throttle openings and set the fuelling and ignition to produce the most torque safely at that rpm. Then you progress to the next rpm point. It's called steady-state tuning. You can't do that on the road properly as you can't hold a particular point steady, so it's much harder. Once you've got it set up on the dyno you then do things like the acceleration enrichment, overrun etc on the road. Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 14, 2007 Share Posted February 14, 2007 An engine dyno allows you to hold temps and pressures easily, and to alter cam timing easily, fix any leaks easily, and in general is just totally superior. Not many people want the hassle though, or the expense, but it can make a big difference to how well and engine gets mapped. Link to comment Share on other sites More sharing options...
csa Posted February 14, 2007 Author Share Posted February 14, 2007 to wrap this up....1.6 shouldn't be completely out of reach right? I was thinking of doing 2 pragrams on for 99 pump on 1.6 bar and one for 109 racefuel on 1,85 bar Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 14, 2007 Share Posted February 14, 2007 It has got forged pistons, hasn't it? Link to comment Share on other sites More sharing options...
Wez Posted February 14, 2007 Share Posted February 14, 2007 Slightly off topic but arent the engine internals under alot more pressure than 2bar during the combustion process? Link to comment Share on other sites More sharing options...
dandan Posted February 14, 2007 Share Posted February 14, 2007 Significantly more, which is why the blanket statement banded around by people of "no more than 1.4bar on pump fuel" seems very odd to me. It depends on turbo, cams, static comp ratio, cam timing, gasket thickness, deck height, squish, piston cooling, coatings, fuelling, ign timing and spark energy, intercooling, manifold and turbine housing sizing, water injection.....to mention just a few things. It's not the extra pressure rise (say 35psi max) over the combustion pressure but the related issues of all the extra airflow being pumped through the motor that is the issue. Someone may be able to run 1.6bar all day long on Optimax, someone else running a different setup and even a LOWER compression ratio (if other things are not correct) may det at anything over 1.2bar. It all depends on the individual setup. My 0.02p worth. Choose a skilled mapper who you trust! Link to comment Share on other sites More sharing options...
csa Posted February 15, 2007 Author Share Posted February 15, 2007 It has got forged pistons, hasn't it? I'ts running on stock internals all the way through. but the block, top and internals are basicly new. Only done about 5K miles Link to comment Share on other sites More sharing options...
dandan Posted February 15, 2007 Share Posted February 15, 2007 Ian C runs a good 600bhp on his stock internals (not cams though) and has done 000's of miles on that setup to date Stock bottom end is by no means ideal for max reliability or performance but with careful conservative mapping you should be ok on pump fuel power outputs in a road car. Take things steady on the rolling road and see how she goes as you gradually increase the boost pressure. Sensible steady mapping and a safe tune is a large part of the battle Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 15, 2007 Share Posted February 15, 2007 I'd want to see forged pistons unless it's purely a road car, and you won't be taking it on track. Link to comment Share on other sites More sharing options...
csa Posted February 15, 2007 Author Share Posted February 15, 2007 track use will be very limited, so it is basicly a street car Link to comment Share on other sites More sharing options...
Supra71GTS_Ice Posted February 16, 2007 Share Posted February 16, 2007 I'd want to see forged pistons unless it's purely a road car, and you won't be taking it on track. what do you mean forged. The Stock pistons are forged and are very good in a TT supra. The Stock pistons are not the weak link they have held more then 1000rwhp. Link to comment Share on other sites More sharing options...
Gamer Posted February 16, 2007 Share Posted February 16, 2007 Just how long do you think the stock items can hold 1000hp then ? A ticking time bomb comes to my mind. Link to comment Share on other sites More sharing options...
dandan Posted February 16, 2007 Share Posted February 16, 2007 The stock pistons aren't forged and in high boost/power/heat applications will deform (more than a good forged piston would) producing excessive blowby. The stock pistons are very good but they are not forged although they are much better than a regular cast piston. Link to comment Share on other sites More sharing options...
Supra71GTS_Ice Posted February 16, 2007 Share Posted February 16, 2007 Just how long do you think the stock items can hold 1000hp then ? A ticking time bomb comes to my mind. i wasn´t saying that they would hold for ever. Just pointing out that the pistons are not the weak link. Chris made it sound like the stock pistons are weak, and they are far from being weak the weak link in the stock supra engine are the rod bolts Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 16, 2007 Share Posted February 16, 2007 The standard pistons are cast. I still say I'd want to have forged pistons in an engine making that much power. Link to comment Share on other sites More sharing options...
Supra71GTS_Ice Posted February 16, 2007 Share Posted February 16, 2007 To answear your inital question. The stock headgasket is used in many high powered supras over 1000rwhp and is very strong. But i think tuning would be your main concern, even the strongest most expensive things you can buy can get destroyed soon if the tuning is bad here is some more info on the stock pistons so nobody gets the mistake that they are somehow weak Taken from this thread http://www.supraforums.com/forum/showthread.php?t=337578 Batlground went 8's on the stock pistons. Quote from Sound-Performance guys The stock pistons are VERY good..... I dont know many people that have broken one from power.... only from running lean or detonation. Quote from Silver Bullet Have had stock pistons...for 5 years now ranging from 700-900rwhp...and been down track a million times. Stock pistons are very durable and i dont see a problem of another 100rwhp all the time. The way i see it....if something goes wrong to melt a piston/motor...no matter what you got in there it will get hurt. But my stock ones will soon have 1000rwhp on them. Link to comment Share on other sites More sharing options...
Ian C Posted February 16, 2007 Share Posted February 16, 2007 the weak link in the stock supra engine are the rod bolts Only when the rev limit increases, not simply through more power. -Ian Link to comment Share on other sites More sharing options...
csa Posted February 16, 2007 Author 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? Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 16, 2007 Share Posted February 16, 2007 To answear your inital question. The stock headgasket is used in many high powered supras over 1000rwhp and is very strong. But i think tuning would be your main concern, even the strongest most expensive things you can buy can get destroyed soon if the tuning is bad here is some more info on the stock pistons so nobody gets the mistake that they are somehow weak Taken from this thread http://www.supraforums.com/forum/showthread.php?t=337578 Batlground went 8's on the stock pistons. Quote from Sound-Performance guys The stock pistons are VERY good..... I dont know many people that have broken one from power.... only from running lean or detonation. Quote from Silver Bullet Have had stock pistons...for 5 years now ranging from 700-900rwhp...and been down track a million times. Stock pistons are very durable and i dont see a problem of another 100rwhp all the time. The way i see it....if something goes wrong to melt a piston/motor...no matter what you got in there it will get hurt. But my stock ones will soon have 1000rwhp on them. 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 Link to comment Share on other sites More sharing options...
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