putting p90head on a 75 280z Block

[Gollum]

Don't sweat so much about the tune. I think I stated this before, but the added quench you get from flat top pistons will counter act the increase in compression. Tunes will be nearly identical, you'll just want to pull some timing, which is probably what killed your last engine.

[z-ya]

A better statement might be 'No US SPECIFICATION L28'...

 

There are PLENTY of JDM engines floating out there as replacements which not only have flat tops, but in some cases SLIGHT DOMES.

 

Not to pick nits Tony, but I did say "280Z", not Fairlady. As far as I know the 280Z wasn't available in Japan. So I am correct in saying no 280Z came with flat top pistons.

 

Correct me if I'm wrong (and I know you will).

 

Pete

[z-ya]

Don't sweat so much about the tune. I think I stated this before, but the added quench you get from flat top pistons will counter act the increase in compression. Tunes will be nearly identical, you'll just want to pull some timing, which is probably what killed your last engine.

 

 

What? Don't sweat the tune on a 20psi turbo motor? That is the problem here. He has no idea what the ignition map looks like inside that Haltech. Until I see the ignition map I wouldn't push any boost on that engine.

 

Pete

Edited July 9, 2010 by z-ya

[ktm]

What? Don't sweat the tune on a 20psi turbo motor? That is the problem here. He has no idea what the ignition map looks like inside that Haltech. Until I see the ignition map I would push any boost on that engine.

 

Pete

 

Not to mention that his tune was for an assumed stock F54 (dished?) block and is not setup for a 0.30 over N42 with flat top pistons.....

 

His tune IS his problem and it will only be worse with his new block.

[280zbeeT]

well you what I actually learned yesterday when I pulled my old engine? the ORIGINAL Engine that I bought this car with, that was the original setup for this car that was ready for 20lbs, WAS A n42 block with DISHED PISTONS! It was never a f54 block!! the only difference now is the .30bore and flat top pistons!I wish I new a good reliable person in san diego to help me with this tune..

[Gollum]

What? Don't sweat the tune on a 20psi turbo motor? That is the problem here. He has no idea what the ignition map looks like inside that Haltech. Until I see the ignition map I wouldn't push any boost on that engine.

 

Pete

 

Ummm, I never said the tune wasn't A problem, I'm just stating that the flat tops WON'T be a problem.

 

...that's all.

 

If he had issues with the tune before, he'll still have issues. Turn the boost down to 10, should be fine unless it's a massacre.

 

If his tune was "perfect" (which we know it wasn't) then it should be reasonably close, hence the point of my post. I might dial the low end of the timing map back a little for part throttle use, but under boost at high rpm should be pretty good.... again, if already perfect.

[280zbeeT]

well, its not perfect, Im adding a MSD 6a (for now, see how it goes maybe get the LS coil pack of its a better choice, in the upcoming month), the tune wasnt perfect, but the car ran good had and gave good boost, sounded smooth, but something had to be off, were putting this engine with the MSD6a, only difference, and different engine.. Im also putting in my newer 240sx tranny since while during this swap we found out my tranny was busted.. I dont know how to tune or haltech at all, so my buddy is gonna do a slight street tune, since I have wideband, and Ima keep the boost at 5 untill I get it tuned.. but I guess 10 might be okay huh?

[280zbeeT]

thanks again guys for all your help.

 

Im so excited to finish the build in the next day or two..

So Ima have a brand new freshly built block, the head only has 2kmiles on it since the rebuild, and a newer 100kmiler 240sx tranny, and brand new 20miles on the clutch! eee oh and ofcourse ALL new gaskets everything you can think! *jumps with joy* next is to tackle this ignition setup..