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L28et bottom end build question


bianski

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ok......so.....here we go

 

i am building a 280z driftamacar but... i havent been able to get away from the HP bug. So i plan on building an engine for 400hp but thats not the important part,the important part is does anyone know where i can get some forged turbo pistons?? i know that people have been custom ordering them left and right. Does a place sell them now to where i dont have to call and speak at people? OR can i use the flat tops forged and use a larger headgasket to bring compression back down or does that screw up the reliablity that i am looking for? Also to finish this up what are the 280zx rods good up to hp wise?

 

Thanks for your help hyb

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off the top of my head im not sure i think a P90a head and whatever block that comes with it I think its F54? and also im gonna be drifting with this car so the engine needs to be very reliable lol it might not be very necessary but i want a tough engine thats gonna take the abuse without having lots problems cuase its gonna be going with a drift schedule.

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A forged piston will also break if the tune is bad (detonation).

 

stock piston can hold 400hp. (crank hp).

 

compression tolerance will depend on the engine setup. longer duration cam, bigger turbo, free flowing turbine, efi tune, ect. What are your plans for a cam and turbo?

 

The most important thing to get is a proper efi system with ignition timing control and a good tune.

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those answers are to none of the questions i asked: these are the questions i asked nothing more lol thankyou but your going off on stuff i didn't ask and i don't wanna get off topic lets reiterate. i wanna know if i still have to custom order oem dimension forged tubo pistons OR if i can use flattop forged pistons and use a thicker head gasket and have the same reliability tunes and turbine sizes are just speculation becuase anything can happen i want to know mechanically are they the same in reliablility

 

if you must know the setup i wanna run here it is:

ARP head and rod bolts

front mount intercooler

Blitz DD bov

FORGED PISTONS (of some kind)

550cc inj

Turbonetics TO4B super V stage 5 .63 on exhuast side

MS 3.0

60mm TB

kamerari 9,000 RPM valve springs (for drifting holding out revs)

walbro 255 LPH fuel pump

methanol inj

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"i wanna know if i still have to custom order oem dimension forged tubo pistons OR if i can use flattop forged pistons and use a thicker head gasket and have the same reliability tunes and turbine sizes are just speculation becuase anything can happen i want to know mechanically are they the same in reliability"

 

Well, if you are going to get a custom set of forged pistons made, then don't make them to oem dimensions Instead of making a round dish, you should make a D-shaped dish that matches the combustion chamber shape. This helps quenching, which reduces ping. FYI, stock dish is about 12cc.

 

installing a 2mm gasket on a 8.8:1 cr L28 (flat top with p90 or p79) will make 8.3:1 cr.

 

You didn't spec your cam but it sounds like you are after high rpms, so a bigger cam must be used. Furthermore, a stage 5 turbine flows well, so more overlap (bigger cam) can be tolerated. Therefore, you are needing a cam like a MSA turbo stage 2 or 3 to match the turbine and the high rpm requirement. These cams will work well with higher compression than the stock turbo 7.4:1 cr . So, it would be better to used 8:1 cr or maybe 8.3:1 cr (stock 75 to 80 compression ratio). You could rebuild a 75 280 Z long block to stock specs and install a msa stage 3 turbo cam and get good results (no thick head gasket required)

 

Thicker gaskets aren't a good idea. It messes with the timing chain. you would require an adjustable timing gear to set the cam timing correctly (unless the chain is stretched a lot).

 

of course a forged piston is stronger, however, a stock piston can handle 400hp. detonation will kill the stock piston sooner than the forged but both will break if the engine detonates. Forged pistons required a bigger clearance in the cylinder bore to allow for thermal expansion. so, when cold they tend to be noisy when slapping around in the bore and produce blowby until warm. This can reduce engine life in a street car.

 

not sure a to4b-v compressor will make 400 hp, have you checked the compressor maps?

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how old are we? cmon guys id understand it if it was if i could turbo my n/a L28 but this is a ligament question. Ive looked around on the posts and most of them get off topic, dont have the right thread title or don't finish because of people thread jacking or people generaly screwing around so i appreacite and commend you on not contributing to this forum .

 

pyro-(thanks for not being an arrogant fool like alot of the people seem to be on this forum)

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how old are we? cmon guys id understand it if it was if i could turbo my n/a L28 but this is a ligament question. Ive looked around on the posts and most of them get off topic, dont have the right thread title or don't finish because of people thread jacking or people generaly screwing around so i appreacite and commend you on not contributing to this forum .

 

pyro-(thanks for not being an arrogant fool like alot of the people seem to be on this forum)

 

I dont think you are going to get much help going after people that did actually give you an answer. Your question was "does anyone know where i can get some forged turbo pistons??". You them procede to ask " OR can i use the flat tops forged and use a larger headgasket to bring compression back down or does that screw up the reliablity that i am looking for?".

 

You did get you answer. Wich was had you taken the time to do a little searching around YOURSELF, you would have come across several forged piston options for the turbo L28.

 

FYI - More searching will show a factory L28 Shortblock is capeable of 400whp+.

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I dont think you are going to get much help going after people that did actually give you an answer. Your question was "does anyone know where i can get some forged turbo pistons??". You them procede to ask " OR can i use the flat tops forged and use a larger headgasket to bring compression back down or does that screw up the reliablity that i am looking for?".

 

You did get you answer. Wich was had you taken the time to do a little searching around YOURSELF, you would have come across several forged piston options for the turbo L28.

 

FYI - More searching will show a factory L28 Shortblock is capeable of 400whp+.

 

click the search button in my sig for some more search help from Challenger :mrgreen:

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I checked the maps on the t04b-v trims and it looks like the compressor will work as long as the engine doesn't build max boost under 3600 rpm. Which is about what the T3 stage 5 turbine does on a L28. The v trim compressors will surge on a L28 with a stock T3 turbine (low rpm boost).

 

Furthermore, will need to run about 14 psi with a cam that makes max power at 6500 rpms (around a stage 2 or 3 msa turbo cam) to hit the 400hp goal.

 

good luck with your build.

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"i wanna know if i still have to custom order oem dimension forged tubo pistons OR if i can use flattop forged pistons and use a thicker head gasket and have the same reliability tunes and turbine sizes are just speculation becuase anything can happen i want to know mechanically are they the same in reliability"

 

Well, if you are going to get a custom set of forged pistons made, then don't make them to oem dimensions Instead of making a round dish, you should make a D-shaped dish that matches the combustion chamber shape. This helps quenching, which reduces ping. FYI, stock dish is about 12cc.

 

installing a 2mm gasket on a 8.8:1 cr L28 (flat top with p90 or p79) will make 8.3:1 cr.

 

 

You didn't spec your cam but it sounds like you are after high rpms, so a bigger cam must be used. Furthermore, a stage 5 turbine flows well, so more overlap (bigger cam) can be tolerated. Therefore, you are needing a cam like a MSA turbo stage 2 or 3 to match the turbine and the high rpm requirement. These cams will work well with higher compression than the stock turbo 7.4:1 cr . So, it would be better to used 8:1 cr or maybe 8.3:1 cr (stock 75 to 80 compression ratio). You could rebuild a 75 280 Z long block to stock specs and install a msa stage 3 turbo cam and get good results (no thick head gasket required)

 

Thicker gaskets aren't a good idea. It messes with the timing chain. you would require an adjustable timing gear to set the cam timing correctly (unless the chain is stretched a lot).

 

of course a forged piston is stronger, however, a stock piston can handle 400hp. detonation will kill the stock piston sooner than the forged but both will break if the engine detonates. Forged pistons required a bigger clearance in the cylinder bore to allow for thermal expansion. so, when cold they tend to be noisy when slapping around in the bore and produce blowby until warm. This can reduce engine life in a street car.

 

not sure a to4b-v compressor will make 400 hp, have you checked the compressor maps?

 

Very much agree, maby an add:

 

Ceramic stock flat tops, and/or, meth injection.

This can save money. If you go for forged and detonate to death, which CAN happen in one pull, you will loose less money.

I will assume here:

The chances of killing a piston with just one of the things added above will give you approx the same amount of blowing a stocker vs. forged.

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I think what Pyro originally posted was highly important to keep in mind. Simply throwing together a bunch of parts without knowledge on how they'll react together is definitely an equation for disaster. There's quite a few people on here in the 400hp range. Most of them have gone to great lengths to ensure the longevity of their motors.

 

I'd suggest you read the sticky on head pics and descriptions, as well as the thread about squish or quench if you haven't already. After that, read some more.

 

Your fuel injection method and means of tuning it are also going to play a key role in how long you "maintain reliability." I see you posted how you plan to do so, but your first remark at Pyro's reply was a bit over the top I think.

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yeah i have a lot to learn so i am putting this all together gingerly and hoping for the best. I am also traveling to St.Louis to go to a reputable tuner so i will have professional help when it comes to the tuning. and as for my remark sorry about that i just get frustrated when everyone wants to drop knowledge and not answer any of my questions or just be a jerk and after the 10th post of that happening it gets tiring so sorry about that.

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