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Using a P90 on a Carb'd Engine


steve260z

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Do I need to weld or fill in the injector ports a my P90 when used with an N36 (260z) intake manifold? Or will the diameter of the N36 simply cover them? Using SUs on a stroker.

thanks

steve

 

 

The simple answer is no, you don't need to do any welding or filling on the head. Test fit the gasket if you have any doubt. I'd suggest a simple search since there is ample info on adapting stock 240Z SU's to a much larger displacement engine.

 

Since the P90 was a turbo head with a turbo cam, the bigger question would be to select a matching cam to work better with the NA application...

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The simple answer is no, you don't need to do any welding or filling on the head. Test fit the gasket if you have any doubt. I'd suggest a simple search since there is ample info on adapting stock 240Z SU's to a much larger displacement engine.

 

Since the P90 was a turbo head with a turbo cam, the bigger question would be to select a matching cam to work better with the NA application...

 

Thanks, I currently have a stage 2 Schneider cam installed on my current car. (Thats why I haven't test fit the head/n36 yet.)

Steve

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I have the same set-up you're looking to do. Stroker - F54 block, P90 head, 480/274 cam, running SU's with SM needles. Its a fun street motor.

Awesome! The SM needles work fine? Rev to 6500 with no problem?

Edited by steve260z
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I'm still trying to figure out whats up with the motor in my car.

 

I believe the block is an F54, or whatever block had the extra webbing added, I remember that. (I did look at the stamp, I forgot what it was).

 

The head is a P90, and I have SU's.

 

What 'should' this net in HP/Tq?

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I'm still trying to figure out whats up with the motor in my car.

 

I believe the block is an F54, or whatever block had the extra webbing added, I remember that. (I did look at the stamp, I forgot what it was).

 

The head is a P90, and I have SU's.

 

What 'should' this net in HP/Tq?

Hard to know if its stroked for sure...Does it have a metal head gasket? Could be one clue

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Steve260Z, Like I said, its a great street set-up for me. If you are looking for ultimate peak HP while running carbs, I would say look at going with some triples. But for my driving and my car's purpose, I do not need triples (though I do have 40 DCOE Weber's sitting in a box). I like the low-end response with SU's and they pull just fine for me.

 

Kris.is.awesome, so you have a F54/P90 running SU's...if its the stock turbo motor converted to carb, with the stock dished piston's meant for turbo applications...then I wouldnt imagine you are pushing more than 120-130 hp at the wheels...if that. But I honestly have no idea what a stock turbo motor (without the turbo and converted to carb) makes power wise. I just know your compression ratio (stock) is going to be around 8:1 or something...not exactly ideal for a NA performance motor...great for turbocharged applications, but not for NA.

 

"How to modify your Nissan/Datsun OHC engine" might be a good book to buy. It can be purchased on Amazon. You can also play with this. Not sure how accurate it is, but its fun anyways.

 

http://www.atlanticz.ca/zclub/techtips/calcs/engine%20builder/index.html

Edited by T-Bone028
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Oh, just read your post again Kris, if you arent sure whats in your engine, then all bets are off.

 

If you got flat-tops in there with a slightly aggressive cam and some headwork on the P90, I would say you're in good shape for having some fun. I guess the only way to find really out is to tear it open...or take it to the track and see what kind of time you run so you can "estimate" your HP using one of those calculators. I would probably do that before I tore apart a perfectly good motor out of curiosity. Cheers and Good luck!

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Hard to know if its stroked for sure...Does it have a metal head gasket? Could be one clue

 

Hmm, let me go have a look-see.

 

 

Steve260Z, Like I said, its a great street set-up for me. If you are looking for ultimate peak HP while running carbs, I would say look at going with some triples. But for my driving and my car's purpose, I do not need triples (though I do have 40 DCOE Weber's sitting in a box). I like the low-end response with SU's and they pull just fine for me.

 

Kris.is.awesome, so you have a F54/P90 running SU's...if its the stock turbo motor converted to carb, with the stock dished piston's meant for turbo applications...then I wouldnt imagine you are pushing more than 120-130 hp at the wheels...if that. But I honestly have no idea what a stock turbo motor (without the turbo and converted to carb) makes power wise. I just know your compression ratio (stock) is going to be around 8:1 or something...not exactly ideal for a NA performance motor...great for turbocharged applications, but not for NA.

 

"How to modify your Nissan/Datsun OHC engine" might be a good book to buy. It can be purchased on Amazon. You can also play with this. Not sure how accurate it is, but its fun anyways.

 

http://www.atlanticz.ca/zclub/techtips/calcs/engine%20builder/index.html

 

Ouch, let's hope they didn't just slap the head/block/su's together without changing the pistons...

 

 

Oh, just read your post again Kris, if you arent sure whats in your engine, then all bets are off.

 

If you got flat-tops in there with a slightly aggressive cam and some headwork on the P90, I would say you're in good shape for having some fun. I guess the only way to find really out is to tear it open...or take it to the track and see what kind of time you run so you can "estimate" your HP using one of those calculators. I would probably do that before I tore apart a perfectly good motor out of curiosity. Cheers and Good luck!

 

Well, there's only one way to REALLY know.

 

I have a buddy with a nice snake cam, maybe I can shoot in one of the plug holes and see what pistons are in there.

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Steve260Z, Like I said, its a great street set-up for me. If you are looking for ultimate peak HP while running carbs, I would say look at going with some triples. But for my driving and my car's purpose, I do not need triples (though I do have 40 DCOE Weber's sitting in a box). I like the low-end response with SU's and they pull just fine for me.

 

Kris.is.awesome, so you have a F54/P90 running SU's...if its the stock turbo motor converted to carb, with the stock dished piston's meant for turbo applications...then I wouldnt imagine you are pushing more than 120-130 hp at the wheels...if that. But I honestly have no idea what a stock turbo motor (without the turbo and converted to carb) makes power wise. I just know your compression ratio (stock) is going to be around 8:1 or something...not exactly ideal for a NA performance motor...great for turbocharged applications, but not for NA.

 

"How to modify your Nissan/Datsun OHC engine" might be a good book to buy. It can be purchased on Amazon. You can also play with this. Not sure how accurate it is, but its fun anyways.

 

http://www.atlanticz.ca/zclub/techtips/calcs/engine%20builder/index.html

T,

 

Thanks, yeah just a weekend ride. Regarding Kris, anything is possible but he needs to look at the block. N42 then dished pistons...F54 could be either. If I remember correctly. One would hope if someone put the p90 on their flat tops are underneath.

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Steve, Then I say, go with SU's. If you have the cash and they could use a rebuild, send them to ztherapy and have them rebuild them for you or have them install their throttle plate with their special ball-bearing roller-shaft throttle plate thing. I would also spring for the SM needles at the same time. Nothing like knowing your carbs wont need to be fiddled with other than some slight adjustments every once in a while.

 

I'm happy with SU's with SM needles on my stroker. Its simple, it works, its fun, and its street friendly.

 

Kris, if you were a little closer, I would say lets go for a ride and compare. If you're in the NoVA area anytime soon, feel free to hit me up.

Edited by T-Bone028
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