Chow Posted January 26, 2009 Report Share Posted January 26, 2009 I'm having my head sent out and wanted to put bigger valves in it. I've doing some searches but don't really seem any talking about it. I have a 1998 S70 T5 engine. From what I have gathered, you can go with a 44mm intake valve and a 40mm exhaust valve..... Is this a good set up? Over kill or for not for street??? So far I'm having my turbo sent out 16t and putting a 19t wheel in it, S60r headgasket, S60r exhaust manifold, N/A cams, and rods (not sure which ones yet) is there anything else you guys can think of???? Oh ya, I'm also looking for a set of green injectors tooThanks Link to comment Share on other sites More sharing options...
lookforjoe Posted January 26, 2009 Report Share Posted January 26, 2009 I'm having my head sent out and wanted to put bigger valves in it. I've doing some searches but don't really seem any talking about it. I have a 1998 S70 T5 engine. From what I have gathered, you can go with a 44mm intake valve and a 40mm exhaust valve..... Is this a good set up? Over kill or for not for street??? So far I'm having my turbo sent out 16t and putting a 19t wheel in it, S60r headgasket, S60r exhaust manifold, N/A cams, and rods (not sure which ones yet) is there anything else you guys can think of???? Oh ya, I'm also looking for a set of green injectors tooThanksWhy 60R headgasket? That will lower your compression - are you planning on using the 60R longer reach plugs also? Link to comment Share on other sites More sharing options...
Chow Posted January 26, 2009 Author Report Share Posted January 26, 2009 Why 60R headgasket? That will lower your compression - are you planning on using the 60R longer reach plugs also? MORE Boost :) Link to comment Share on other sites More sharing options...
lookforjoe Posted January 26, 2009 Report Share Posted January 26, 2009 MORE Boost Really not necessary with only a 19T. I'm running 23psi with a 19T, and you're pretty much running out of steam at that point - that's why I'm going to do a 20G :D Link to comment Share on other sites More sharing options...
ozzimark Posted January 26, 2009 Report Share Posted January 26, 2009 MORE Boost I know there are a ton of factors that you must consider when increasing boost, but I feel like lowering compression is something that should be done as a last resort. With good tuning, you shouldn't have any problems running >30psi on the stock compression :ph34r: Link to comment Share on other sites More sharing options...
Chow Posted January 26, 2009 Author Report Share Posted January 26, 2009 So do you know what size of valves that I might want to go with? Link to comment Share on other sites More sharing options...
lookforjoe Posted January 26, 2009 Report Share Posted January 26, 2009 I know there are a ton of factors that you must consider when increasing boost, but I feel like lowering compression is something that should be done as a last resort. With good tuning, you shouldn't have any problems running >30psi on the stock compression Are you sure about that?Others have suggested that 24psi is pushing it - especially on non-race fuel. Perhaps it also depends on the turbo's flow capabilities/& exhaust backpressure levels - but a 19T is definitely tapped out by 24psi as far as I can tell. Link to comment Share on other sites More sharing options...
ajhehr Posted January 26, 2009 Report Share Posted January 26, 2009 so we all know that the S60R manifold is a MLS piece correct?with that said. the MLS gasket will actually prevent allot of things, like mild cylinder float to an extent. and who said lowering compression (by a small amount) is a bad thing? from a longevity standpoint it makes allot of sense.yes tha map on a 19t is about done by 24 PSI. water meth injection could get some of that heat energy back.I also have a question as to why your modding a 16t with a 19t wheel?19t's are cheep. IMHO, save the money youd spend on the oversize valves and get a GOOD MAPABLE water meth injection system...OR>>> go buy a gt28r and crap yourself...other then that, make sure you CORRECTLY install the MLS gasket and go have fun! Link to comment Share on other sites More sharing options...
EricF Posted January 26, 2009 Report Share Posted January 26, 2009 Are you sure about that?Others have suggested that 24psi is pushing it - especially on non-race fuel. Perhaps it also depends on the turbo's flow capabilities/& exhaust backpressure levels - but a 19T is definitely tapped out by 24psi as far as I can tell.I think you'd be quite surprised with difference in overall VE with a high-flowing turbine and exhaust side. You'll find that with turbos that have a higher flowing turbine component, you will not need as much boost level to make the same power levels. With proper tuning on a dyno, I bet in terms of peak power, you will be at the same level with a GT3071R and 17-18 psi as you would be with 22-23 psi on a 19T (where it effectively runs off the end of the compressor map IIRC). You can also probably get more power with pump gas due in part to lower EGTs.I also agree with the notion that there is no need for the S60R head gasket.. If anything it might make it more detonation-prone because the bores on the gasket are too big for the cylinders. Stock compression is more than low enough.I have datalogged 28-29 psi on a 19T.. And seen 23-25 psi on a daily basis with a T3/T04E Garrett hybrid turbo.. Stage 3 turbine wheel and .63 AR housing, 57 trim T04E compressor wheel.What needs to be paid attention to at these higher levels is ignition timing and air/fuel ratio. If you are using pump gas, EGT is maybe more important than air/fuel... Link to comment Share on other sites More sharing options...
EricF Posted January 26, 2009 Report Share Posted January 26, 2009 On a side note, you can lower effective compression ratio by retarding the intake cam timing. The intake valve will spend more time open while the piston is traveling upward on its compression stroke. Link to comment Share on other sites More sharing options...
ozzimark Posted January 26, 2009 Report Share Posted January 26, 2009 Joe, no hard proof, but really there is no reason you would have any issues with detonation or pinging at 8.5 CR if you/your tuner knows what is going on with ignition timing and AFR. And as you implied, a free flowing setup is critical, especially on the exhaust side to keep EGTs down. If you wonder why I say that 30psi is possible, consider your setup.. You have an off-the shelf tune with a restrictive turbine running pretty well up to 24 psi, no? There's always Charles' S60. Definitely north of 30psi on 9.3 CR iirc, though that has race fuel and is heavily, so moot point.Dah, you beat me Eric :P Link to comment Share on other sites More sharing options...
ozzimark Posted January 26, 2009 Report Share Posted January 26, 2009 What needs to be paid attention to at these higher levels is ignition timing and air/fuel ratio. If you are using pump gas, EGT is maybe more important than air/fuel...I think that with TurboTuner's release, we need a good thread in which we can discuss these three things, and how they should be used to tune for maximum reliable power. I get annoyed every time someone makes a blanket statement like "run it richer to run more boost" or "advance ignition as much as possible for the most power" <_< Link to comment Share on other sites More sharing options...
EricF Posted January 26, 2009 Report Share Posted January 26, 2009 I think that with TurboTuner's release, we need a good thread in which we can discuss these three things, and how they should be used to tune for maximum reliable power. I get annoyed every time someone makes a blanket statement like "run it richer to run more boost" or "advance ignition as much as possible for the most power" I would like to understand more about timing on pent-roof chambered cars... Maybe I'll start one? I know the basics on timing and the general guidelines.. But it would be interesting to try to ferret out opinions of people who have tuned these things on a dyno before. Hm. Link to comment Share on other sites More sharing options...
ozzimark Posted January 26, 2009 Report Share Posted January 26, 2009 I would like to understand more about timing on pent-roof chambered cars... Maybe I'll start one? I know the basics on timing and the general guidelines.. But it would be interesting to try to ferret out opinions of people who have tuned these things on a dyno before. Hm.I know the feeling. I'll be taking an Internal Combustion Engine Design class next quarter, so that'll probably help me out a bunch. Until then, I'm in the same situation, I know the basic principle, and some of the underlying theory, but lack any exposure to the actual tweaking of these engines. I know there are several places that have quite a lot of experience with it though, otherwise there would be no off-the-shelf tunes out there. Go ahead and make a thread, I'm sure there will be a lot of interest in it :lol: Link to comment Share on other sites More sharing options...
EricF Posted January 27, 2009 Report Share Posted January 27, 2009 I know the feeling. I'll be taking an Internal Combustion Engine Design class next quarter, so that'll probably help me out a bunch. Until then, I'm in the same situation, I know the basic principle, and some of the underlying theory, but lack any exposure to the actual tweaking of these engines. I know there are several places that have quite a lot of experience with it though, otherwise there would be no off-the-shelf tunes out there. Go ahead and make a thread, I'm sure there will be a lot of interest in it The thread is underway... Don't hold your breath. Time to go mix up a nice gin n tonic so I don't shoot myself for watching myself type the nerdiest shit imaginable :lol: Link to comment Share on other sites More sharing options...
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