S14 SR Rebuild OEM+ vs Forged?

[Future240]

Yo. I am getting a notchtop rebuilt. I can either get an OEM+ rebuild (oem pistons and rods, better head studs, acl bearings and a few other goodies) or I can go the forged bottom end route, pistons and rods.

Thing is not sure if it worth for me. I will never drift the car. I do not plan to drag it either. At best more of a street machine for the tail of the dragon and whenever I cross the border into Mexico maybe a few highway pulls against other cars.

Power goals are modest. 350whp seems more than enough for an S-chassis. I do not want a car spinning tires 1st-3rd.

My rationale is 350whp is nearing the upper limit of the stock rods/pistons and would not last as long, vs a built engine would be bullet proof (assuming tune and all that is fine) and will last longer.

However lately I have been seeing discussion on built motors, the clearances are not as tight so piston slap can be a thing and they do not last as long as an oem engine.

What do yall think?

Budget is not the issue here. Not trying to save money. I just want an SR I can enjoy for the next decade or more that can handle what I throw at it.

[PoorMans180SX]

Well, there's a few points to make here.

First is about engines failing. Most engines are taken out by bad fuel, bad injectors, or a faulty tune. Built engines taken out by improper assembly usually fail within the first 50 miles. Whether it's built or stock, you have a much higher chance of killing it if you don't make sure your fuel, timing, and injectors are always on point.

Second is about engine limits. It really comes down to torque and how soon you want to make it, because this is really what determines cylinder pressure. A EFR6258 on an SR making 400wtq at 3500rpm is way harder on the engine than a 3076 that only makes 350wtq at 6000rpm even thought it will make bigger horsepower numbers. You have to take this into account when you talk about the limits of the pistons and rods.

Thirdly, piston cylinder-to-wall is only one clearance. You can offset this by using something like Mahle forged 4032 pistons with high silicon content. This allows you to run tighter piston to wall and have that OEM like startup-and-go kind of engine but still have stronger than stock pistons. This can also reduce cylinder wall wear compared to a big power 2618 setup with big cylinder-to-wall.

Bearing clearances should be opened up on almost any engine you're going to beat on or make more power on. This should be accompanied with an appropriate increase in oil viscosity. SR20 blocks are not very stiff and move around quite a bit, and factory tolerances are just not up to snuff when the engine is wrung out. I think this is the main mistake people make when building SR's and making power.

Now you can see that there is a lot of minutia in making the choice between built and stock. Depending on turbo choice, I would say going with Mahle pistons and stock rods, opening up the bearing clearances, and doing the dual rocker guide mod would leave you with a very reliable engine as long as you weren't trying to make too much torque.

As an example, I have a EFR 6258, and I elected to put forged rods and 2618 pistons in so I can let that thing eat as much air as it can at low rpm and make the two liter drive like a five liter. I also plan to beat the living daylights out of it, and would like as much margin as possible when it comes to detonation. I probably could have gone with a high silicon piston and been fine though.

[Future240]

I was thinking of going with CP pistosn and Manley rods with an 8:5:1 compression. Or just CP pistons and stock rods. I would not be the one building it. A shop called Night Owl Performance would be doing the build.

Turbo choice at first would be the stock S14 turbo on 555cc injectors. Later on I would upgrade to a GTX2871R .64 A/R.

[Future240]

Fuck database errors bump.

[Corbic]

I was thinking of going with CP pistosn and Manley rods with an 8:5:1 compression. Or just CP pistons and stock rods. I would not be the one building it. A shop called Night Owl Performance would be doing the build.

Turbo choice at first would be the stock S14 turbo on 555cc injectors. Later on I would upgrade to a GTX2871R .64 A/R.

My recommendations -

Buy a legit ECUand new Wire Harness and injectors.
Wiring Specialties has harnesses that will support Link G4+, Haltech and ECUMasters. Do not use some garbage AEM, Empathy, Apexi crap from the 90's.

Buy Top-Feed ID1050X Injectors (Injector Dynamics). Modern injectors destroy those garbage side-feeds in terms of responsiveness and tune-ability.

With this, you can now run a GM E85 Flex Fuel sensor, Wide-Band, MAP and ECU Boost-Controller (AEM).

You'll have a reliable, consistent and accurate platform to tune off of and won't have issues with injector balance, detonation, stupid MAF's, boost control, etc. You'll have full diagnostics to see what's going on.

That's going to set you back $4k

Injectors $600
Harness $750
ECU $1,300
MAP, Wide-Band, E85 Sensor, Pump, fuel line, top rail, etc - $1,000

So once that's out of the way, how much money do you have?

With SR's, Cams seem almost more important then the turbo. I wouldn't waste my time running the S14 turbo since the cermic wheel may grenade and take out you're whole engine. Better off to run a Shanghi Shooter for $200 if you need to save for a turbo. At least then you'll just risk blowing an oil seal.

By now, it's like... what's another $1000 to make sure you don't crack a ring land or snap a rod bolt?

Certainly run ARP head-studs, not only are they stronger, but they are easier to torque. Don't run a MLS gasket unless you have the head and block decked. You need a perfect surface to seal with MLS.

[inopsey]

My recommendations -

Buy a legit ECUand new Wire Harness and injectors.
Wiring Specialties has harnesses that will support Link G4+, Haltech and ECUMasters. Do not use some garbage AEM, Empathy, Apexi crap from the 90's.

Buy Top-Feed ID1050X Injectors (Injector Dynamics). Modern injectors destroy those garbage side-feeds in terms of responsiveness and tune-ability.

With this, you can now run a GM E85 Flex Fuel sensor, Wide-Band, MAP and ECU Boost-Controller (AEM).

You'll have a reliable, consistent and accurate platform to tune off of and won't have issues with injector balance, detonation, stupid MAF's, boost control, etc. You'll have full diagnostics to see what's going on.

That's going to set you back $4k

Injectors $600
Harness $750
ECU $1,300
MAP, Wide-Band, E85 Sensor, Pump, fuel line, top rail, etc - $1,000

So once that's out of the way, how much money do you have?

With SR's, Cams seem almost more important then the turbo. I wouldn't waste my time running the S14 turbo since the cermic wheel may grenade and take out you're whole engine. Better off to run a Shanghi Shooter for $200 if you need to save for a turbo. At least then you'll just risk blowing an oil seal.

By now, it's like... what's another $1000 to make sure you don't crack a ring land or snap a rod bolt?

Certainly run ARP head-studs, not only are they stronger, but they are easier to torque. Don't run a MLS gasket unless you have the head and block decked. You need a perfect surface to seal with MLS.
never thought i would agree with corbic but most of this is good advice.



but i would not recommend opening the engine just to do head studs/gasket. leave the head gasket to be the weak point, so it goes before the bottom end preventing the block from becoming a piece of scrap aluminum. however, the tune and safety cuts that a ecu like haltech offers are gonna be key here.



source: ive been running 370whp (mustang dyno) for 10 years now with a proper tune (haltech all the way) on a 3071 at 18 psi (with stock cams) and the engine has the same compression numbers as when the turbo was first put on the car.

[e1_griego]

LOL I almost made the same post. "Can't believe I'm agreeing with Corbic buuuuut..."

I did the stock head gasket thing for many years, and also ran the apexi crap from the 90s for a long time. A real ecu (Link g4+) didn't add any power but is a LOT more peace of mind what with actual control of things and failsafes added in.

[Future240]

never thought i would agree with corbic but most of this is good advice.



but i would not recommend opening the engine just to do head studs/gasket. leave the head gasket to be the weak point, so it goes before the bottom end preventing the block from becoming a piece of scrap aluminum. however, the tune and safety cuts that a ecu like haltech offers are gonna be key here.



source: ive been running 370whp (mustang dyno) for 10 years now with a proper tune (haltech all the way) on a 3071 at 18 psi (with stock cams) and the engine has the same compression numbers as when the turbo was first put on the car.

Dont have a choice. I bought it with a spun bearing and owner did not want to have it rebuilt. Block is good. Crank either is or is not. If not will buy another one.

[spooled240]

My recommendations -

Buy a legit ECUand new Wire Harness and injectors.
Wiring Specialties has harnesses that will support Link G4+, Haltech and ECUMasters. Do not use some garbage AEM, Empathy, Apexi crap from the 90's.

Buy Top-Feed ID1050X Injectors (Injector Dynamics). Modern injectors destroy those garbage side-feeds in terms of responsiveness and tune-ability.

With this, you can now run a GM E85 Flex Fuel sensor, Wide-Band, MAP and ECU Boost-Controller (AEM).

You'll have a reliable, consistent and accurate platform to tune off of and won't have issues with injector balance, detonation, stupid MAF's, boost control, etc. You'll have full diagnostics to see what's going on.

That's going to set you back $4k

Injectors $600
Harness $750
ECU $1,300
MAP, Wide-Band, E85 Sensor, Pump, fuel line, top rail, etc - $1,000

So once that's out of the way, how much money do you have?

With SR's, Cams seem almost more important then the turbo. I wouldn't waste my time running the S14 turbo since the cermic wheel may grenade and take out you're whole engine. Better off to run a Shanghi Shooter for $200 if you need to save for a turbo. At least then you'll just risk blowing an oil seal.

By now, it's like... what's another $1000 to make sure you don't crack a ring land or snap a rod bolt?

Certainly run ARP head-studs, not only are they stronger, but they are easier to torque. Don't run a MLS gasket unless you have the head and block decked. You need a perfect surface to seal with MLS.This is sound advice, but overkill for his goals imo. I know he said money wasn't an issue, but for the sake of argument I think investing in hardware is a better priority with SR's. Reducing the flexing of the block, keeping the valvetrain from exploding and keeping things very cool are paramount for these engines longevity. 350whp can easily be made on an OEM+ setup using the dated electronics, pump gas and a gt2871r (See Codyace's old SR setup)

[Corbic]

This is sound advice, but overkill for his goals imo. I know he said money wasn't an issue, but for the sake of argument I think investing in hardware is a better priority with SR's. Reducing the flexing of the block, keeping the valvetrain from exploding and keeping things very cool are paramount for these engines longevity. 350whp can easily be made on an OEM+ setup using the dated electronics, pump gas and a gt2871r (See Codyace's old SR setup)

I wouldn't call the electronics overkill. It makes it easier to tune and work with while also future proofing the car while not costing much more money.

An Apexi FC is what, $900? Compared to a Link G4+ that's can be had for $1,100.

IDX1050 are like $550 compared to what, $450 for 550 SF? You need to upgrade the pump one way or the other and a 485 is only like an extra $30 over the default 255. GM Map sensor is like $30 compared to a knock off Z32 MAF at $150 or a used POS.

So unless you really are trying to save pennies here and there - just "do it right".

Then it's easier to tune, more reliable to tune, you have more control and more options in the future. You can then go with throttle-by wire, multiple fuel maps (91, 93, e85, race) etc. With an ECU controlled boost solenoid you can they have ramp up boost, scramble boost, etc.

Its easier to data log, you don't need a dash full of gauges but can have them all go to a multi function screen or just blue-tooth over to you phone.

As for the new harness - we're dealing with cars that are pushing 30 years old, junk yard motors that have been swapped dozens of times. Connectors are all broke, wires corroded, etc. Its just so damn nice to have a new harness that drops right on in and you don't have to fight wiring issues for hours and day.

Having done it the hard way myself on multiple cars and having seen others do it the hard way for now over a decade - this is the best advice I can give.

The great thing is, all this stuff is future proof for when 300-350whp wants to be 350-450 to +500. Or if you want to run some big cams or ditch the cam sensor for a crank sensor, etc.

[Corbic]

Dont have a choice. I bought it with a spun bearing and owner did not want to have it rebuilt. Block is good. Crank either is or is not. If not will buy another one.

Can you run a FWD crank? For whatever reason I've seen a ton of FWD SR20's recently in the PHX yards. Been so long I can't remember what parts swap to a RWD engine.

[Corbic]

never thought i would agree with corbic but most of this is good advice.



but i would not recommend opening the engine just to do head studs/gasket. leave the head gasket to be the weak point, so it goes before the bottom end preventing the block from becoming a piece of scrap aluminum. however, the tune and safety cuts that a ecu like haltech offers are gonna be key here.



source: ive been running 370whp (mustang dyno) for 10 years now with a proper tune (haltech all the way) on a 3071 at 18 psi (with stock cams) and the engine has the same compression numbers as when the turbo was first put on the car.

You can run head studs without pulling the head. Just pull one bolt at a time and add the stud in. I did that on my SR.

LOL I almost made the same post. "Can't believe I'm agreeing with Corbic buuuuut..."

I did the stock head gasket thing for many years, and also ran the apexi crap from the 90s for a long time. A real ecu (Link g4+) didn't add any power but is a LOT more peace of mind what with actual control of things and failsafes added in.

Yeah, a quality standalone won't make "more power". It just makes running and tuning the engine easier. No more chasing weird issues when the engine over fuels at a certain RPM or cuts timing or has a high or rough idle. On and on. It becomes really easy to identify if you have a mechanical issue or a tune issue and what issue is.

[spooled240]

I wouldn't call the electronics overkill. It makes it easier to tune and work with while also future proofing the car while not costing much more money.

An Apexi FC is what, $900? Compared to a Link G4+ that's can be had for $1,100.

IDX1050 are like $550 compared to what, $450 for 550 SF? You need to upgrade the pump one way or the other and a 485 is only like an extra $30 over the default 255. GM Map sensor is like $30 compared to a knock off Z32 MAF at $150 or a used POS.

So unless you really are trying to save pennies here and there - just "do it right".

Then it's easier to tune, more reliable to tune, you have more control and more options in the future. You can then go with throttle-by wire, multiple fuel maps (91, 93, e85, race) etc. With an ECU controlled boost solenoid you can they have ramp up boost, scramble boost, etc.

Its easier to data log, you don't need a dash full of gauges but can have them all go to a multi function screen or just blue-tooth over to you phone.

As for the new harness - we're dealing with cars that are pushing 30 years old, junk yard motors that have been swapped dozens of times. Connectors are all broke, wires corroded, etc. Its just so damn nice to have a new harness that drops right on in and you don't have to fight wiring issues for hours and day.

Having done it the hard way myself on multiple cars and having seen others do it the hard way for now over a decade - this is the best advice I can give.

The great thing is, all this stuff is future proof for when 300-350whp wants to be 350-450 to +500. Or if you want to run some big cams or ditch the cam sensor for a crank sensor, etc.

If you're starting from scratch then I would agree. If you already upgraded all of this stuff, your wiring harness is still in good shape and your goals are 350whp or less I wouldn't stress. I'd much rather overbuild the fck out of the block as it would just add to the reliability.

I found this video interesting: https://www.youtube.com/watch?v=YlXx8eCAYvE

[e30gangsta]

IF you're already in there, do it once and do it right.

manley rods, 86.5mm 9:1 compression pistons, new oil pump, mazworx head studs, not the arp's since they do not bottom out in the block, apexi hg, new s14 pickup, and a new oilpump. Get the bests sr builder's in america to build the block for you. Aka mark at mazworx.

[Corbic]

IF you're already in there, do it once and do it right.

manley rods, 86.5mm 9:1 compression pistons, new oil pump, mazworx head studs, not the arp's since they do not bottom out in the block, apexi hg, new s14 pickup, and a new oilpump. Get the bests sr builder's in america to build the block for you. Aka mark at mazworx.

Mazwork headstuds are ARP Headstuds, just likely a different part number then what ARP sells for the SR20.

https://www.mazworx.com/store/p/141-Mazworx-SR20-Head-stud-Kit.aspx

[RalliartRsX]

I also agree with Corbic sans head gasket.

Put a MLS in there. I have seen the stock HG fail and literally torched both the block and head because the coolant becomes like a blow torch and melts the AL.



And DO NOT pussy out on the ECU. Is not about tuning capabilities, but more about failsafes and inputs (data stream) to better monitor all parameters of the engine. That's key.


The tuning logic varies from ECU to ECU, but the sub $1500-$2K ECUs are very capable in that regard.

[RalliartRsX]

Can you run a FWD crank? For whatever reason I've seen a ton of FWD SR20's recently in the PHX yards. Been so long I can't remember what parts swap to a RWD engine.

FWD 8CW is exactly the same as the RWD 8CW.

You can also swap a 4CW FWD into a RWD. Everything is the same sans the removal of 4CW

[Corbic]

I also agree with Corbic sans head gasket.

Put a MLS in there. I have seen the stock HG fail and literally torched both the block and head because the coolant becomes like a blow torch and melts the AL.

It's not that I believe a OEM style gasket is sufficient, it's just that a MLS needs to be properly installed or it will be leaking right off the bat.

[RalliartRsX]

Agreed. If he has the engine opened up, better get the block and head surfaced at which point, plop in a MLS

[Future240]

The plan all along was to get a wiring specialties harness. Piece of mind and I don’t feel like messing with that much loom.

On the ecu. Corbic called it. I had planned to go with an Enthalpy tune. I’d like a haltech but not sure if anyone in ATL are experienced with tuning them.

While budget is not a huge concern I don’t want to over spend just to spend. This car will never drift. Very little track use. Just a fun street car TBH so diminishing returns is a concern.

I want to do it right and not have it spin another bearing or blow a HG. If I was going to run 400-500 whp I’d buy another car. I want my S14 to be enjoyable without having to constantly worry about lighting up the rear tires.

I do some looking around and see what is available around here tuning wise.

Keep talking. Y’all are giving me some good info.

[tb13]

The plan all along was to get a wiring specialties harness. Piece of mind and I don?t feel like messing with that much loom.

On the ecu. Corbic called it. I had planned to go with an Enthalpy tune. I?d like a haltech but not sure if anyone in ATL are experienced with tuning them.

While budget is not a huge concern I don?t want to over spend just to spend. This car will never drift. Very little track use. Just a fun street car TBH so diminishing returns is a concern.

I want to do it right and not have it spin another bearing or blow a HG. If I was going to run 400-500 whp I?d buy another car. I want my S14 to be enjoyable without having to constantly worry about lighting up the rear tires.

I do some looking around and see what is available around here tuning wise.

Keep talking. Y?all are giving me some good info.

Chip tunes are junk, every engine is different and they aren't tailored for your specific intercooler/exhaust setup. Not to mention you have no way of knowing if something is wrong with the car other than a blinking light.

I don't think you should look at an ECU from a point of needing the functionality, but from a perspective of wanting to know what is going on with the engine at all times. You're dropping the cash to re-build the engine, doesn't it make since to protect that investment?

Something like a Link G4X is relatively affordable, easily tuned by most tuners and will give you the ability to setup fail safes for oil pressure, fuel pressure, knock, AFR, etc. Along with having fail safes, you can log issues to easily diagnose and fix them before you lose an engine. The peace of mind added from knowing the ECU is looking after your engine is well worth the cost of going standalone in my opinion.

[mav1178]

all this talk about parts and no actual discussion about the engine.

the real questions are about what your goals are, not just power output.

How long do you intend to keep the engine?
How many miles per year?

If people can run turbo KA on stock, untouched internals for 10+ years with a basic ROM tune from the mid-2000s, then you can do the same on your SR. The same general rules apply, i.e. who is building your engine, how aggressive your tune is, etc etc...

If you want longevity then you recreate what Nissan had on the SR... a basic tune with failsafes built in to protect the engine.

A lot of the parts discussed here are great, but from what is discussed you don't need more than a clean, proper stock internal rebuild + a good tune done right the first time. What parts you use will probably be dictated by the direction the builder wants to go, and who you use for tuning.

[Future240]

I hope you don't mind me undeleting this. You brought up some good points.


all this talk about parts and no actual discussion about the engine.

the real questions are about what your goals are, not just power output.


How long do you intend to keep the engine?
How many miles per year?

As long as the car is on the road honestly. Less than 10K. This will not be my DD. Even if it was I permanent work from home so I mostly drive to the gym and/or grocery to the tune of 7 miles 2-5 times a week


If people can run turbo KA on stock, untouched internals for 10+ years with a basic ROM tune from the mid-2000s, then you can do the same on your SR. The same general rules apply, i.e. who is building your engine, how aggressive your tune is, etc etc...

I considered this. I know someone who has an SR with an Enthalpy tune who can spin tires in 3rd gear but has been running it for 10 plus years.

After reading the posts in here was thinking about going with a Haltech unit
https://www.haltech.com/product/ht-150853-elite-1000-nissan-200sx-silvia-s15-and-s14a-s2/

If you want longevity then you recreate what Nissan had on the SR... a basic tune with failsafes built in to protect the engine.

A lot of the parts discussed here are great, but from what is discussed you don't need more than a clean, proper stock internal rebuild + a good tune done right the first time. What parts you use will probably be dictated by the direction the builder wants to go, and who you use for tuning.

So you think I do not need to go the forged route?

I hope you don't mind me undeleting this. You brought up some good points.

[Kingtal0n]

100% go stock rebuild and DIY, don't let any machine shop touch the engine

built engines don't last long
SRs that built and failed quick

http://zilvia.net/f/showthread.php?t=535520

http://zilvia.net/f/showthread.php?t=569861

http://zilvia.net/f/showthread.php?p=5765974

http://zilvia.net/f/showthread.php?t=579996

http://zilvia.net/f/showthread.php?t=586960

http://zilvia.net/f/showthread.php?t=415523&page=2

http://zilvia.net/f/showthread.php?p=5951668#post5951668


I stopped keeping track many years ago, this is just a small fraction


my advice is to use a stock engine. Stock engine list of HP support for daily drivers:
sr20det up to around 320-350rwhp (you can 450rwhp or even 500rwhp if you are an tuning expert with much experience)
2jz-gte and LSx are 500-600rwhp capable daily (up to 800rwhp to 1200rwhp is possible using L33 engine with expert tuning)

If you are dead set on a rebuild then do a STOCK rebuild and follow FSM procedure, and do NOT allow a machine shop to touch the engine. If you need something "cleaned" or "shaved" buy another identical part that doesn't need that work done, never send it to the machine shop. That's where most mistakes occur. You will wait weeks/months for something and it will be done wrong, and you won't even know it until it costs the entire engine.

All that said forged engines have their place. If you intend to heavily, strictly track the vehicle at high temperature and high output (over 500rwhp for many hours) then a forged piston is the only way to go. The purpose of forged pistons is to deal with extended high temperature situations, they use a greater piston/wall clearance and can handle more temperature than a cast unit, and must fully warm up 30-40minutes before full power can be used.
To put it another way, the bane of forged internals is the cold start of a daily driver engine. Cold starting (80*F is cold start) a forged engine puts more wear and tear on the internals than any amount of driving or racing abuse (when tuned properly). You must start the engine then wait for the oil temperature to reach approx 180-210*F and the piston has become 600*F+ for it to fully expand in the bore before driving the engine hard or it will wear rapidly. Thus forged internals, in any engine, have no place in daily driver situations unless a special forged alloy and considerations are met which are beyond this short details.

$.02

[RalliartRsX]

LOL. And here comes king with all his.....single minded experience

Built engines last a while. The key is, who builds them

[Kingtal0n]

LOL. And here comes king with all his.....single minded experience

Built engines last a while. The key is, who builds them

It isn't experience. It's engineering. The specification for low silicone alloy forged pistons literally call for increased piston to wall clearance. The machine shops that build an engine for you will ignore the fsm specification for rod bearings of .0014 or whatever and use a .0022" automatically instead. And so forth.

Those settings and common practice contribute to increased wear and tear, reduced life expectancy, there is nothing you or anybody else can do or say to change that.
The fact the pistons need to warm up and expand in the bore further complicates usage in street applications.

I am sure that *I* could build and operate a forged, built engine successfully for hundreds of thousand mileage.
I never said a built engine could not last long in the right hands.
In 2007 I built an sr20det/2jz and it still runs fine w/ CP pistons and Eagle rods... knife edged crankshaft...

Walked the walk. What I learned is that the OEM oil system of an SR20 and 2JZ are NOT Up the challenge of cold-start city with those engines, they require an accumulator pre-oil to protect rod bearing #1 and #2 respectively.
They also require light load, pre-warming engine oil to 180*F-220*F before loading to protect piston skirts and cylinder walls from damage in daily driver applications where the vehicle is being operated within the first 30-50minutes of being started at ambient 80*F temperatures. Colder ambients = more pre-warming.

If you can manage those two big issues it goes a long way to maintaining 'built' engine reliability. But few people understand the requirements or are willing to go that far. There are also a few easily overlooked oil-related issues with the bearing system to deal with, journal chamfer and oil orifice work typically seen in small block Chevrolet engines for example, as well as Enlarging accessible oil passages is necessary.
Another overlooked issue is Measuring oil flow rate throughput instead of merely recording oil pressure, and adjusting flow rate accordingly.
Crankcase pressure management is also absolutely essential- you *must* measure and correct PCV flow rate to achieve the necessary 1 to 2" Hg of vacuum at wide open throttle and for cruise situations.

It's too much work for a daily driver that could make much more power with a $500 truck engine, avoid all that BS and call it a day
I built one of those also and being honest here... it is far more satisfying and much less stressful knowing you can toss the engine out and grab another for the cost of a pair of tires and be back on the road the next day with 600rwhp, driving the engine cold-started oil temps sitting on 100*F boosting 20psi silently through the gears getting sideways at 7am on the way to school/work without a care 2 minutes after you started the 200,000 mile, 20 year old engine that just doesn't care because its basically built like a twin 2jz from the 90's.

[spooled240]

It's really not that complicated to run forged pistons..and some of them have offset wrist pins to reduce piston slap and friction: http://blog.wiseco.com/what-is-wrist-pin-offset

If the OP was building a stock SR I'd say go for a stock rebuild, but he mentioned 350whp which is about double the power with much higher heat compared to what the original engine was designed to do. I would recommend investing in parts that are designed for much higher heat tolerances, even if they require a short warm-up cycle.

[Kingtal0n]

It's really not that complicated to run forged pistons..and some of them have offset wrist pins to reduce piston slap and friction: http://blog.wiseco.com/what-is-wrist-pin-offset

If the OP was building a stock SR I'd say go for a stock rebuild, but he mentioned 350whp which is about double the power with much higher heat compared to what the original engine was designed to do. I would recommend investing in parts that are designed for much higher heat tolerances, even if they require a short warm-up cycle.

the original engine from 1998-2002 is approx 300rwhp capable. 350 is nothing for that engine. I have made/tuned out 420rwhp for around 14+ years on stock sr20det engines, fully confident in their ability at that meager output.

I would not put a forged piston into an SR20DET unless I was aiming for over 500rwhp.

The 2jz-gte is another great example for this situation, as it is basically an sr20 piston. The stock 2jz-gte piston config supports 600rwhp easily, no questions asked, for 20+ years (supraforums contains this historical data) so figure a minimum of 100rwhp per piston is absolutely acceptable. We can further extrapolate this data to confirm that V8 LS engines which also use the same type of cast-aluminum piston are capable of around 1200rwhp for the similar reasons (pressure/area) mathematically speaking, and in practically application these data hold up.

Caveat, you must be a master tuning artist. Not just call yourself one but actually be one capable af. The cast aluminum piston is a brittle piece, and piston temperature must be carefully set and monitored in the minds eye. Very few people understand the purpose of 100% distilled water injection to this end or have utilized such features to protect their engine, yet it becomes absolutely critical if you intend to glean 100% reliability for 200,000 mileage at just over the sort of power output I am discussing here.

To put it another way... of course 98% of individuals are going to say that the stock piston isn't capable or is too weak for XXX power. That is because they lack the skill set necessary to make it work to it's full potential. Forged pistons are a crutch that allow one to be terrible at engine config and worse at tuning because forged piston withstand the abuse of ignorance at the cost of mileage capability and reliability not to mention quintupling the cost of said engine.

[spooled240]

I'm not saying it won't work and by all means run that shit if your stock engine is already in the car. I just wouldn't want the smallest margin of error with stock internals if I'm doing a full engine rebuild. I'd always trade a bit of practicality for a more forgiving motor, just my .02.

[Future240]

So what about a semi built engine forged rods, stock pistons?

[RalliartRsX]

Why?? The engine is already open, spend the few hundred and get the proper forged pistons.

Stock SR piston in any SR is at the least 20+ years old.....

Spend the money on the right builder, and your shit will be reliable for a LONG time. King just hasn't found the right sauce/recipe yet

[Future240]

Why?? The engine is already open, spend the few hundred and get the proper forged pistons.

Stock SR piston in any SR is at the least 20+ years old.....

Spend the money on the right builder, and your shit will be reliable for a LONG time. King just hasn't found the right sauce/recipe yet

When I say stock pistons I meant new ones.

[RalliartRsX]

Nope. Stock pistons are not cheaper by any significant margin than a forged piston for me to even consider it.....much less that they are a 30 to 40 year old design and spec

No thanks

[spooled240]

So what about a semi built engine forged rods, stock pistons?With your goals you could even go with stock rods with forged pistons

[PoorMans180SX]

I'm telling you, get some Mahle pistons if you're really concerned about the forged piston slap and engine wear. The high silicone forgings are stronger than stock but expand less with heat. They really are the best option for a 'daily driver medium power' style forged engine build. https://www.us.mahle.com/media/usa/motorsports/nissan-sr20det-2020-web.pdf

If you're going to be on pump gas, you don't need the upped compression of most pistons anyway.

[RalliartRsX]

^^ Yep. That is where my mind is at too.

No reason to go with stock piston with today's offerings.
Tech has progressed immensely in the years since a full SR swap was 2K picked up from an importer

[e30gangsta]

I actually have a set of those mahle power pack pistons for sale if anyone is interested. I will let them go for cheap and they're brand new.

[Future240]

Aight, So Mahle pistons, go it. I was thinking eagle rods.

[PoorMans180SX]

Aight, So Mahle pistons, go it. I was thinking eagle rods.

I know there are plenty of people who have had good luck with Eagles over the years, but to me their quality control is subpar, or at least was a few years back. We've had some come through with big ends out of spec, and we had a series of them break at power levels they should not be breaking at.

I would go with Manley if you want the cheap h-beams, but I think it's worth the one-and-done of the big boy I-beams, or Wiseco boostline. For 'safety's sake'.

[NiSilS14]

I'm surprised no one has touched on this, but it's crucial a machine shop bore and hones with torque plate especially with alloy blocks. They tend to distort more then cast iron engines. Also adding in ARP head studs and/or ARP main studs will distort them even more. Mahle pistons are great, I've used them in customer builds as well as my own cars. The ptw clearances are tighter with 4032 alloy pistons so be sure the machine shop is aware of that. If you are able to, always triple check the work after getting it all back.

[Future240]

^^^^The shop I am getting to build the SR is
https://www.facebook.com/NightOwlPerformance/

It is a local shop so I doubt yall have any thoughts on it.

I know there are plenty of people who have had good luck with Eagles over the years, but to me their quality control is subpar, or at least was a few years back. We've had some come through with big ends out of spec, and we had a series of them break at power levels they should not be breaking at.

I would go with Manley if you want the cheap h-beams, but I think it's worth the one-and-done of the big boy I-beams, or Wiseco boostline. For 'safety's sake'.

Manley rods are so cheap it makes me kinda worried lol. I am looking at the Tomei Rods.

https://www.rhdjapan.com/tomei-h-beam-conrods-set-sr18de-sr20de-t.html

[RalliartRsX]

Manley holds a pretty significant market share

I wouldn't pay the premium for #jdm when stateside stuff is not only cheaper, but in some cases, better.

My 0.02c

[splitfire]

...
I would not put a forged piston into an SR20DET unless I was aiming for over 500rwhp.
...
...
To put it another way... of course 98% of individuals are going to say that the stock piston isn't capable or is too weak for XXX power. That is because they lack the skill set necessary to make it work to it's full potential. Forged pistons are a crutch that allow one to be terrible at engine config and worse at tuning because forged piston withstand the abuse of ignorance at the cost of mileage capability and reliability not to mention quintupling the cost of said engine.

very well said. I completely agree and do not take stock pistons on my OWN sr engine past 400bhp. If I wanted more I would step up to a V8 or 2J, forget opening the sr20 IMO.


Seems like you changed your mind a bit over the years :)