Noddle Posted March 9, 2009 Share Posted March 9, 2009 Hi, Just finished setting up my NA / Turbo conversion, and I was wondering what is a safe psi to run on my NA block, my engine specs are: L24, using a P30 Block, dished pistons N47 head RB30 injectors (about 200 cc) EDIS Megasquirt no intercooler yet, but intake is about 37C average I start to drop spark when boost comes on, see attached picture the waste gate actuator is factory set for 10 psi, but I've added a external spring, and when testing with a compressor, it starts to open at 3-4 psi when running in the car, if I powers slowly it maxed out at 5psi, but if I power into it quickly, it maxes out at 10 psi, but I must say I love the power, and the way it throws you back into the seat. I haven't held it flat for more than 5 seconds or so, and I haven't tried it out above 3rd gear, since 3 flat out is speeding.. any insights would be helpful Nigel Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted March 9, 2009 Share Posted March 9, 2009 thanks for posting the timing map. I'm going to run a very similar setup, factory T3 on my F54 block with N/A internals. -Ed Quote Link to comment Share on other sites More sharing options...
boardkid280z Posted March 10, 2009 Share Posted March 10, 2009 Timing map looks good. Do you have any type of AFR gauge? wide or narrow band? What fuel pressure are you running with those injectors? They are kind of small and you might start running out of fuel, which could heat up the pistons and make them melt Have you figured out what your compression ratio is? What kind of head gasket are you using? Since you have dished pistons, that's better than flattops, so you can run more boost. But intercooling would be really helpful, I'm pretty surprised your intake temps are only 37C (~100F). What does it get it up to when you get on it? What's the max temp you've seen? I think they're have been non-turbo dished piston builds running quite a bit of boost and quite a bit of power, as long as you keep the temps down with plenty of fuel and low intake temps, etc. Interested in seeing how much power you make, do you have any pics? -Brazle Quote Link to comment Share on other sites More sharing options...
Noddle Posted March 10, 2009 Author Share Posted March 10, 2009 "Do you have any type of AFR gauge", I have a wide band that lives in the car "what pressure are you running with those injectors?" the gauge says 32psi without vacuum "Have you figured out what your compression ratio is" No "What kind of head gasket are you using" standard Nissan one "I'm pretty surprised your intake temps are only 37C (~100F). What does it get it up to when you get on it" when logging (I checked last night), flat out in the first 3 gears it reached 70C "do you have any pics?" my web site.. http://noddle.110mb.com/ The engine is out of a MR30 skyline, L24e Nigel Quote Link to comment Share on other sites More sharing options...
boardkid280z Posted March 10, 2009 Share Posted March 10, 2009 What kind of turbo is that, and what kind of fuel pressure regulator are you using? Nice intercooler man, get that set up! Quote Link to comment Share on other sites More sharing options...
Noddle Posted March 10, 2009 Author Share Posted March 10, 2009 "What kind of turbo is that", I brought it second hand, .50 AR Compressor, .63 AR Turbine, .57 Trim "what kind of fuel pressure regulator are you using". the standard N/A one that was on the engine. Nigel Quote Link to comment Share on other sites More sharing options...
(goldfish) Posted March 13, 2009 Share Posted March 13, 2009 If IRCC bigphil ran over 20 on his. But the real killer is detonation, esp a turboed NA block w/o intercooler. Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 16, 2009 Share Posted March 16, 2009 I have run 21 psi on a stock 77 JDM N/A Block for over 40K miles since 1989. Don't Detonate. Quote Link to comment Share on other sites More sharing options...
Noddle Posted March 16, 2009 Author Share Posted March 16, 2009 Thanks for the reply s, So 20ish is maximum by the looks, I'll need to finish setting up my intercooler sooner, rather than later by the looks. Nigel Quote Link to comment Share on other sites More sharing options...
240hoke Posted March 16, 2009 Share Posted March 16, 2009 You need basically perfect tuning to run 20psi reliably on the factory pistons. One mess up and your ring lands are toast. So if you do run 20psi do it on the dyno and ramp up slowly. Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 24, 2009 Share Posted March 24, 2009 I didn't have a dyno access until almost 5 years after I set it up. Then it was more for a power check than anything else. Go rich and work backwards and don't get greedy. I know people in the Mid-20's, but you can make things go boom if you run a metal headgasket---much quicker than if you run something like a Fel-Pro that will let go when you detonate. Those metal head gaskets are great, but not for pistons! Quote Link to comment Share on other sites More sharing options...
Noddle Posted March 25, 2009 Author Share Posted March 25, 2009 Those metal head gaskets are great, but not for pistons! I'm running a standard type of head gasket, so this should give before I blow anything up I hope, If I run rich at the high end, keep boost down to about 12psi (I have over boosting issues and 12 seems to be where it the maxes out), run my intercooler, I should be ok.. if I blow it up, I have a L28 I can rebuild, but I would need to source dished pistons Nigel Quote Link to comment Share on other sites More sharing options...
240hoke Posted March 30, 2009 Share Posted March 30, 2009 I am not disputing a metal headgasket is harsh on your pistons when you detonate....but I don't think It makes that big of a difference. I busted three pistons running felpro gaskets, never once did I blow a gasket, ever. Quote Link to comment Share on other sites More sharing options...
stony Posted March 30, 2009 Share Posted March 30, 2009 Run hi octane race gas. it will help teh engine live longer. i was running mine on 104 for about 15 runs before i figured out i was starving for fuel thru a bad filter. if i had been running lower pump gas i would have for sure burnt it up. Quote Link to comment Share on other sites More sharing options...
stony Posted March 30, 2009 Share Posted March 30, 2009 here is a video of it before i got the fuel problem fixed... BTW we all thought it was an ignition problem cause on the dyno it was not leaning out and the exhaust temps were not getting too high. thanks to the gas. as soon as we replaced the filter (earls 3 PSI carb filterX2!!!!) it instantly went away. we had to totally re-tune the map after that. Quote Link to comment Share on other sites More sharing options...
ktm Posted March 30, 2009 Share Posted March 30, 2009 I am not disputing a metal headgasket is harsh on your pistons when you detonate....but I don't think It makes that big of a difference. I busted three pistons running felpro gaskets, never once did I blow a gasket, ever. Three head gaskets and no ring damage myself. I guess it's a crap shoot. Quote Link to comment Share on other sites More sharing options...
yo2001 Posted March 30, 2009 Share Posted March 30, 2009 I went through one turbo which had a wg failure and spiked 25+ psi ( gauge only went that far) 4 headgaskets (oem, turbo, felpro) never broke a ring land. The ring lands are pretty far down on the oem n/a piston so it is more forgiven than more modern engine with shallow ring lands design to save gas and hp. Detonation kills piston though. Quote Link to comment Share on other sites More sharing options...
Noddle Posted March 30, 2009 Author Share Posted March 30, 2009 Run hi octane race gas. it will help teh engine live longer. i was running mine on 104 for about 15 runs before i figured out i was starving for fuel thru a bad filter. if i had been running lower pump gas i would have for sure burnt it up. This is a DD (well weekends now), so no high octane fuel for me, Nigel Quote Link to comment Share on other sites More sharing options...
Tony D Posted April 1, 2009 Share Posted April 1, 2009 I am not disputing a metal headgasket is harsh on your pistons when you detonate....but I don't think It makes that big of a difference. I busted three pistons running felpro gaskets, never once did I blow a gasket, ever. The big question I would have in that case is "Did you hear it detonate?" Was this on one engine, or several? I've run I don't know how many stock N/A L's and the HG always seems to blow before the pistons are done. Including the deadliest detonation there is: that which you don't hear! My experience with Turbo Builds like this is restricted to less than a dozen builds, much less than the N/A conversions I've done. But they seem to work the same as the N/A's in my experience, you can just boost slightly higher without 'hearing' the detonation. The parallel between what I've seen in my blown engines, and what KTM has posted in the past is startingly similar. When I saw his photo posts, I even think I pu up one-word posts: "Detonation" I would have to see your engine, that sounds strange for them to go bad like that unless someone previously did bad things, or you had already broken parts in there to begin with and the detonation you did just pushed it over the edge. Quote Link to comment Share on other sites More sharing options...
Noddle Posted April 8, 2009 Author Share Posted April 8, 2009 Hi, I finished my intercooler, and it work wonderful, now I think I may be needing a new clutch, Nigel Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.