big-phil Posted January 23, 2006 Share Posted January 23, 2006 I got a P90 head. I was going to resell it but should I put it on my car? I now have the n47 with my turbo, if I put it on is it going to be a noticeable power gain, or will the turbo spool up faster? what will the difference be? My n42 head was a total rebuild about a year ago, so its almost like new, the P90 has about 150,000 miles on it, so If I'm not going to feel much power gains, or faster spool, or something, I might just leave the n47 on. Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted January 23, 2006 Share Posted January 23, 2006 With just a head only change, I can't see you gaining anything. You may even loose power due to the lower comp. I don't know whats been done to either head, but if stock, you will loose bottom end going to the larger chamber P90. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted January 23, 2006 Share Posted January 23, 2006 don't change it, not yet. Just hold on to it. Get down to the dyno and see where you're at right now, what a/f ratio, and see if you guys hear any ping or see any evidence of ping on the dyno graph (erratic, jagged power curve). You might be alright where you're at. But if you're planning on going higher, more boost eventually (not really recommended on the stock T3 anyways) bigger turbo or whatever, there may come a point where you would want to switch over to the P90, but as it stands right now there is no point and yeah you would probably LOSE power, and more noticeably, you'd lose off-boost throttle response and torque and the car would be less enjoyable during 'normal' driving conditions. Quote Link to comment Share on other sites More sharing options...
Sparks280zt Posted January 23, 2006 Share Posted January 23, 2006 personally i would resell it so you could take that money and change your rubber IC hoses to some hard pipes. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted January 23, 2006 Share Posted January 23, 2006 unless he's really hard up for cash it wouldn't be worth selling it for that. P90 goes for what... $100 these days? I know I've bought at least one for $100 before. Pipes on the other hand... well depends what you want to do. I went with 2.25" stainless steel with mandrel bends and enough silicone couplers, reducers, and a couple silicone 90* bends as well to make it all work, and spent I think $500 including having them cut to size and having my BOV flange welded on. Keep the head, you are more likely to end up needing it some day. Quote Link to comment Share on other sites More sharing options...
big-phil Posted January 23, 2006 Author Share Posted January 23, 2006 I was thinking that I might loose bottom end power. I would like to get it to the dyno, maby I'll sell it to get a NPR, or better intercooler than my Volvo 740 one, and some new plumbing? I have to smile and chuckle everytime I open my hood, and see those radiator hoses, but it works. Thanks agian guys for all the help, this site is the best! Quote Link to comment Share on other sites More sharing options...
Guest ambersdad Posted January 23, 2006 Share Posted January 23, 2006 Phil - I'll give you 100 bucks for it if you want to move it. Let me know. Thanks Quote Link to comment Share on other sites More sharing options...
big-phil Posted January 24, 2006 Author Share Posted January 24, 2006 hey thanks ambersdad, I'm going to take it to a head shop where I got my rebuilt head, and have them do a pressure test on it, if its tight I just might put it on? But if I do want to sell I'll post here, and let you know. Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted February 1, 2006 Share Posted February 1, 2006 if you put on a p90 head you might lose hp-p90 has a huge low compression combustion chamber.alot of people building full tilt turbo l28 use a n42 head.p90 with flat pistons would work.turbo pistons are dished. Quote Link to comment Share on other sites More sharing options...
big-phil Posted February 1, 2006 Author Share Posted February 1, 2006 I think I do have flat top pistons? can't remember it was about a year ago when I put the rebuilt N47 on? Quote Link to comment Share on other sites More sharing options...
boardkid280z Posted February 3, 2006 Share Posted February 3, 2006 The P90 is the newest L28 head that came in the Z car. (new=more advanced). From what I understand it outflows the previous heads which is part of the reason it is more desireable. A second reason is because it has the heart shaped quenching combustion chambers for better combustion. Do a search on www.zcar.com for P90 and N47 and N42 and Maxima N47 and MN47. There have been MANY discussions about these heads and which ones flow better. Lots of information there. Quote Link to comment Share on other sites More sharing options...
big-phil Posted February 3, 2006 Author Share Posted February 3, 2006 Well I found a turbo motor with a p90a head, and a bad turbo for $300, I'm thinking about getting it and putting the p90, and my turbo on it. Is a true turbo motor really THAT much better than what I've got? It would give me a chance to put my new clutch in. Quote Link to comment Share on other sites More sharing options...
pjo046 Posted February 3, 2006 Share Posted February 3, 2006 Well, either way you have a P90 head in your hands(With the different turbocamshaft) So the question is what is the difference between a NA shortblock and a Turbo shortblock. The pistons would be the main difference. The top compression ring is thicker on the NA pistons. The turbo pistons have a 1.5mm top compression ring, whereas the NA pistons have a 2mm top compression ring. Thinner rings have less drag on the engine and have less ring flutter. But this is not a big deal. The other difference is in the internal casting between the two blocks. The later F54 blocks have siamesed cylinders, meaning that instead of coolant flowing between all the cylinders as on earlier models, they are connected between 1-2, 3-4, 5-6 with cast webbing for more rigidity. So the main difference between a Turboengine and a NA is the head and the dished vs flat pistons. If you already have dished pistons in you engine, just spend the 300$ on a T3/T4 hybrid turbo instead or save the money for a better engine management system. Quote Link to comment Share on other sites More sharing options...
pjo046 Posted February 3, 2006 Share Posted February 3, 2006 Also, the block you have now, you know is working. If you swap to that turboblock you are refering to, then you might have to do alot of work to it to get it in proper shape for all you know. I assume you have the original 280Z engine in your car? If so, yes your pistons are dished. So then I'd just put the P90 head on the block you already have. You will loose a lot of CR doing this. The CR you have now if everything is stock is 8.29:1. Putting a P90 on would give you the same CR as the L28ET came with from the factory, 7.38:1. Adding a 1mm HG would do you good. It would raise the compression a tiny bit, to 7.52:1. So if you install the P90 on your engine, be aware that you will loose some power if you don't turn up the boost. But now you can turn up the boost due to the lower CR. But anyways your off-boost power and characteristics will be worse than what you have now. So it all depends on how much power you are hoping to make. If you are shooting for big numbers I'd install the P90, if not I wouldn't bother. Or, you could do as I have done, use the P90 along with flat-tops and get a CR of 8.5:1. Quote Link to comment Share on other sites More sharing options...
TheNeedForZ Posted February 3, 2006 Share Posted February 3, 2006 The other difference is in the internal casting between the two blocks. The later F54 blocks have siamesed cylinders' date=' meaning that instead of coolant flowing between all the cylinders as on earlier models, they are connected between 1-2, 3-4, 5-6 with cast webbing for more rigidity.[/quote'] Hello there, Just an FYI, the thing you mentioned above is a myth floating on the internet that is recently debunked by "1 fast z", a member here. Official literatures like "How to modify you nissan&datsun engine", "how to rebuild you nissan& datsun engine" also disagree with the internet myth : Early L28 block(N42) have webbing between cylinders(1-2-3, 4-5-6, front three, rear three). the turbo block F54 have SLOTs in the webbing, meaning the F54 block is actually weaker than N42 when bored out. That is 1 fast z's conclusion after doing sonic testing on many many L series blocks. He also visually confirmed the webbing in N42 by removing freeze plugs and peeping into the block. Quote Link to comment Share on other sites More sharing options...
pjo046 Posted February 3, 2006 Share Posted February 3, 2006 Hmmm. My bad. But hey, that further confirms that Big Phil should keep the block he has, as it is then stronger than the F54. It seems strange though that Nissan designed a new block that was not as good as the earlier models... Well, well. Quote Link to comment Share on other sites More sharing options...
big-phil Posted February 4, 2006 Author Share Posted February 4, 2006 WOW!! could this be true, my n/a block could be stronger than the f54? somebody give me a "hoot-hoot" ...........boo-ya! Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted February 4, 2006 Share Posted February 4, 2006 well either block is fine for 90% of people here, people who aren't going to go gung-ho crazy with the power. I would imagine the slots in the webbing on the F54 also somehow contribute to better flow and cooling? Really... I would never even bother chasing after this block or that... I just want one that runs early block later block... really not enough difference for almost anyone to really care either way... at least, no one planning on keeping the stock bore.... I guess if you can afford to go three liter stroker you can afford to worry about what block you need Quote Link to comment Share on other sites More sharing options...
TheNeedForZ Posted February 4, 2006 Share Posted February 4, 2006 Yep, F54 or N42 blocks only make a difference when you bore out to the max (3mm, even with the stronger N42 block, sonic check is still necessary). And yes, F54 have better coolant circulation due to the slotted webbing. I am building a 3.0L turbo stroker, I have both the F54 and the N42. I'll be using the N42. Quote Link to comment Share on other sites More sharing options...
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