boostin280zx Posted August 23, 2006 Share Posted August 23, 2006 I melted a hole in my piston about a month ago so i put another motor together. I am using the N/A f54 block w/ the flat top pistons and the turbo p90 head that has been resurfaced 4 times and a stock 1.25mm sized head gasket. I have megasquirt ems w/ 550cc injectors and lc1 wideband. I'm not sure what compression this motor is going to be and what a safe boost level would be on this motor. I was running 13psi on the other motor w/ 25 year old stock inj's for awhile but a injector messed up and i melted the piston. Is anyone boostin with the flat top pistons and how reliable is it? Compression Ratio? Boost? I should have no fuel problems now. Quote Link to comment Share on other sites More sharing options...
Clifton Posted August 23, 2006 Share Posted August 23, 2006 I wouldn't go out and run XX amount of boost because someone with a similar set up is. Don't get crazy with the timing and listen for knock and then back the boost off some. How much did they take off each time they resurfaced? Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted August 23, 2006 Share Posted August 23, 2006 personally I think I would start off slow and work my way up. Whos doing the tuning on your megasquirt? Quote Link to comment Share on other sites More sharing options...
boostin280zx Posted August 24, 2006 Author Share Posted August 24, 2006 I have been tuning it. I make sure im not running to much of a spark advance at high boost. The other motor never pinged or predetonated except that one time. I have no idea how much they shave off the head when they resurface it. It was only warped one time the other times i just got it resurfaced when i changed the head gasket. I think 8 or 9 psi with a good tune will be plenty of power. I haven't put my motor in yet b/c im waiting on flywheel bolts i ordered but i guess i shoulda just went and got them from the dealer. Quote Link to comment Share on other sites More sharing options...
Clifton Posted August 24, 2006 Share Posted August 24, 2006 It was only warped one time the other times i just got it resurfaced when i changed the head gasket. I wouldn't shave it unless it isn't straight. No need to do it everytime the head comes off. You could cc a chamber to figure out the CR. If you are under 9:1 wyou shouldn't have a problem with 15 psi if the timing isn't oo much. Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted August 24, 2006 Share Posted August 24, 2006 I wouldn't shave it unless it isn't straight. No need to do it everytime the head comes off. You could cc a chamber to figure out the CR. If you are under 9:1 wyou shouldn't have a problem with 15 psi if the timing isn't oo much. Looks like good advise to me. Seems like you may be running more compression than you think you are. Quote Link to comment Share on other sites More sharing options...
boostin280zx Posted August 25, 2006 Author Share Posted August 25, 2006 Flywheel bolts came in today so im gonna put the motor in early tommorow and start tuning and break in. Can't wait to get it back on the road again. Quote Link to comment Share on other sites More sharing options...
boostin280zx Posted August 27, 2006 Author Share Posted August 27, 2006 I already drove 200 miles on the motor and it feels awesome. it builds 8 psi in neutral. I has tons of bottom end power and feels faster w/ stock boost now then when i was running 15 psi at the track. Friday ill find out if it really is faster at the 1/8 mile. Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted August 27, 2006 Share Posted August 27, 2006 I already drove 200 miles on the motor and it feels awesome. it builds 8 psi in neutral. I has tons of bottom end power and feels faster w/ stock boost now then when i was running 15 psi at the track. Friday ill find out if it really is faster at the 1/8 mile. Really, 8 lb of boost in neutral just revving the motor? You sure about that? Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted August 27, 2006 Share Posted August 27, 2006 I guess you find that your car feels like a weapon on the street, and a boat at the track. I hate that. Dr_Hunt, I can make just over 5psi in neutral with 3 consequtive WOT jabs on the throttle and thats with a GT35R. Dave Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted August 27, 2006 Share Posted August 27, 2006 are you guys crazy?? an L series motor pushing out ANY boost in nuetral?! im so confused.. i can get 15psi in neutral but thats bouncing off the rev limiter and anti-lag ... Quote Link to comment Share on other sites More sharing options...
boostin280zx Posted August 28, 2006 Author Share Posted August 28, 2006 Im running the stock t3 turbo housings w/ turboneutics internals. So its pretty easy to spool it up under no load. Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted August 28, 2006 Share Posted August 28, 2006 I guess I don't understand the purpose of being able to build boost in neutral reving the engine and how that means anything in regards to performance capability. You didn't specify stabbing the throttle several times to achieve that level of boost, so one can only guess. My understanding was if the throttle was at WOT and you were running a two step that boost could be achieved at launch with a manual trans. Auto is different since you stall the converter which puts the engine under load. I've read corky bells book and sever other sites that grumpyvette so kindly posted about 30 of, I think I read two or three links worth which was a wealth of information. So my understanding of the dynamics of operation isn't real world like alot of you guys on here. While you may do it, how does that show or depict what the car does under load? Help me here if you would. I would think that what you are describing is a turbo that has little if any lag, may be too small and run out of cfm for any top end depending on boost level, but I guess it depends on what your trying to accomplish and what area of the turbo map your running in correct? From what I've read and know, which isn't that much, something doesn't sound right about having that ability without being under load, but maybe you could enlighten me. Quote Link to comment Share on other sites More sharing options...
boostin280zx Posted August 28, 2006 Author Share Posted August 28, 2006 I was just sayin that i could tell it has more compression by just how it spooled in neutral (before it would only boost around 3 psi at redline and now it hit 8psi w/o reving past 5000rpms. True, it doesn't have anything to do performance wise besides that it is a tiny stock t3) . The turbo is too small and i'm gettin rid of it as soon as i replace my rear-end again and cv axles. Quote Link to comment Share on other sites More sharing options...
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