DAT240Z Posted May 1, 2007 Share Posted May 1, 2007 I just got my 240zt running . The bad news is I can't seam to get the ping under control above 7psi. I have up the fuel and turn down the timing to all the way and it still pings. Here's a list of my set up N42 BLOCK felpro head gasket BORE 50MM OVER N42 HEAD STOCK T-3 TURBO 370CC INJECTORS SUPRA INTERCOOLER SDS fuel only computer 77- DISSY. RECURVED TO 15 DEGREE OF TOTAL TIMING BASE TIMING SET TO 10 DEGREE MSD 6BTM BOX SET TO BACK THE TIMING OFF 3 DEGREE UNDER BOOST A friend of my tells me the problem lay in the head as it not right for a turbo application, because of the "quench area". He said if I were to install a P90 head the car will not ping and I can up the boost to m goal of 14psi. Is he right. I thought there were people on here that have ran the N42 with a turbo with out any problem. any help would be appreciated. Thanks Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted May 1, 2007 Share Posted May 1, 2007 I thought there were people on here that have ran the N42 with a turbo with out any problem. any help would be appreciated.Thanks I think a good example of being able to run a N-42 head is here with TimZ's N-42 set up. http://forums.hybridz.org/showthread.php?t=116829 Quote Link to comment Share on other sites More sharing options...
z-ya Posted May 1, 2007 Share Posted May 1, 2007 I just got my 240zt running . The bad news is I can't seam to get the ping under control above 7psi. I have up the fuel and turn down the timing to all the way and it still pings. Here's a list of my set up N42 BLOCK felpro head gasket BORE 50MM OVER N42 HEAD STOCK T-3 TURBO 370CC INJECTORS SUPRA INTERCOOLER SDS fuel only computer 77- DISSY. RECURVED TO 15 DEGREE OF TOTAL TIMING BASE TIMING SET TO 10 DEGREE MSD 6BTM BOX SET TO BACK THE TIMING OFF 3 DEGREE UNDER BOOST A friend of my tells me the problem lay in the head as it not right for a turbo application, because of the "quench area". He said if I were to install a P90 head the car will not ping and I can up the boost to m goal of 14psi. Is he right. I thought there were people on here that have ran the N42 with a turbo with out any problem. any help would be appreciated. Thanks Did you verify that the total advance is 15 degrees with a timing light? Rev it up to 3500RPM in neutral and check the timing with a light. Your CR should be around 8.6:1 (I'm assuming you meant 0.5mm overbore), which should be OK. Stock dish size in the new pistons, right? Note that with a P90 head, your CR will be in the 7.6:1 range. Quote Link to comment Share on other sites More sharing options...
DAT240Z Posted May 1, 2007 Author Share Posted May 1, 2007 pete, I did check the timming,and is's at 25 degree at 3500 rpms. Also the plate on the side of the engine that was placed there when the engine was rebuild by the builder has broed 50mm stamped on it. also I belive the top of the pistons had 50mm on them as well. Yes the pistons are dome. Are you saying the compression is not too high for my set up. Thanks Quote Link to comment Share on other sites More sharing options...
z-ya Posted May 1, 2007 Share Posted May 1, 2007 There is no way 50mm could be added or removed from the pistons anywhere on a L28, so I think the builder meant 0.5mm (which is equal to 0.020"). 25 degrees is a lot more than 15. Try backing the timing off more with the BTM. Also, you really need to know if the pistons in there are dished or not. If they are flat tops, you are over 10:1CR, which will ping like crazy with an N42 head. Quote Link to comment Share on other sites More sharing options...
DAT240Z Posted May 2, 2007 Author Share Posted May 2, 2007 Pete, I just checked the plate on the side of the block, I was wrong it reads 50 thousand. would you have any idea what that would make the compression. Also the pistons are dish Quote Link to comment Share on other sites More sharing options...
z-ya Posted May 2, 2007 Share Posted May 2, 2007 Somewhere in the 8.7:1 range if the dish is the same size as stock. Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted May 2, 2007 Share Posted May 2, 2007 It's in a 240z right? What are you using for the fuel and return lines? The original carb'd source line is too small for some applications, most people swap the source and return lines. Mario Quote Link to comment Share on other sites More sharing options...
The Woj Posted May 2, 2007 Share Posted May 2, 2007 Sorry for not contributing anything useful, but when I saw the title "pining for the fjords" came to mind: Quote Link to comment Share on other sites More sharing options...
TimZ Posted May 2, 2007 Share Posted May 2, 2007 Sorry for not contributing anything useful, but when I saw the title "pining for the fjords" came to mind: LOL that's what I thought of too, but I didn't think anyone would get it. Quote Link to comment Share on other sites More sharing options...
DAT240Z Posted May 3, 2007 Author Share Posted May 3, 2007 Thanks Mario, I did relpace the return to a bigger one when I installed the efi system. Pete do you thing 8:7:1 is too high? Quote Link to comment Share on other sites More sharing options...
Daeron Posted May 3, 2007 Share Posted May 3, 2007 Sorry for not contributing anything useful, but when I saw the title "pining for the fjords" came to mind: "Bea'iful Plumage!!!!" "This.. is an Ex... Parrot!" *I* saw the subject and thought, "I, too, have a problem with pining for my Z.. I havent DRIVEN it in almost THREE YEARS:cry2:" back on topic, though; although I am no sage I will add my two cents that you NEED to find out what kind of pistons you are running. Stock (NOT wildly modified, I should say) N42 head on a high compression turbo motor is going to ping like mad, and if you have domed or flat top pistons in there, then you have high compression.. the N42 head was designed to be used with dished pistons, at a *fairly* mild compression ratio. Quote Link to comment Share on other sites More sharing options...
z-ya Posted May 3, 2007 Share Posted May 3, 2007 Thanks Mario, I did relpace the return to a bigger one when I installed the efi system. Pete do you thing 8:7:1 is too high? At 25 degrees advance, and an N42 head, it might be. Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted May 5, 2007 Share Posted May 5, 2007 are you sure you have dished pistons? Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted May 5, 2007 Share Posted May 5, 2007 what i want-engine to dyno around 400 rwhp -but with a very flat torque curve-with turbo boost very early.engine i have is a 3l stroker with ported n42 head.car has megasquirt efi with 42lb injectors and big intercooler.the cam thats in it now has to go-its to big and boost is late.the turbo is a 60-1/stage 5 t3 .the changes i am thinking of-new ball bearing garret turbo,extrude honed exhaust manifold,custom ground cam.looking for a car that drives like a v8 with good gas mileage on freeway.anybody have a setup like this? Quote Link to comment Share on other sites More sharing options...
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