l28et vs sr swap battle ! but this ones hard

[1 fast z]

I could make a turbo KA have twice the HP as a stock SR and be just as reliable for what an SR cost. Plain and simple. There IS NO replacement for displacement.................

[subtle_driver]

I would assume that from 250-300hp, you would have to have the motor rebuild with better parts, for reliability, on either engine.

 

my ka has been reliable for 2 years, STOCK BLOCK! My KA see's 7k multiple times every day. I'm over 300 hp. But mine is tuned with the stock ecu/chipped. anyways....

[subtle_driver]

I've had an L28 with anywhere from 275 to 350hp, depending on the boost level in my 73 240ZT since 1987. not a whimper on it, and well over 40K+ of HARD miles.

 

People who go for a ride with me in it comment that driving like me in that car is like most people's idea of throttle application at an Autocross. The chassis flexed coming off a corner one day, and cracked my windshield.

 

The L-Engine is reliable at the power level to 100K miles easily I would suspect...if not twice that.

 

Now, at 400HP, I think you decrease reliability accordingly using the stock components. Mine has stock pistons in it, no problem thusfar.

 

But much above this point, I'd likely go with something heavier in the piston department which I would forecast to withstand 500 hp levels in a turbo application the way I drive for 100K miles.

 

That's damn reliable in my book. And curiously, coincides with what Bernard has experienced.

 

People discount the L-Engine. It's a mistake. It's just most people go about modifying it in such a hamfisted way that they screw it up along the way and blame the engine and not themselves. It's not the engine's design problem if someone tuning it is an idiot. But it plays out that way because the engine never gets to tell it's side of the story.

 

I agree! well, its good to hear the stock bottem end on the l28 is strong! Tuning is the key to success! Looks like i'm gonna look forward to plopping one in my z. BTW, anyone have one for sale in SD? pm me! haha

[Guest Jalopi]

I personally don't see why people make a huge fuss over nissan engines that have a turbo stock... this may be my first post here, but that's only because I'm picking up a S30 280z this week.

 

From my experience, nissan makes supidly reliable engines, no matter the application. So far, I've only dealt with the KA, SR and RB series motors, but I'm expecting the L28 to be a beast not to be reckoned with. If you do your research, you'll find that people rock their KA's anywhere from 250~350rwhp and have been doing so for years (and can be done in the ballpark of $2000). Don't get me wrong, because they do have their limits that effect reliability, but SRs are really just for enthusiasts. They'll put the same numbers down on paper with equal amounts of modification - except price.

 

That being said, I'm excited to see what these cars can do! This'll be the oldest car I've ever owned (10 years older than me) so I'm a little apprehensive as to the problems it might have... but hey, its a nissan after all. Sometimes, it almost seems like zipties and JB weld can slove all of your problems.

[whitechocolatelove]

they make a fuss because the TURBO engine is built for TURBO appication and the NATURALLY ASPIRATED engine is built for NATURALLY ASPIRATED application.

the entire engine is built different. they dont want to waste the time and money on an engine that has no potential unless it is rebuilt with the proper

components when they can buy an engine that is designed with that kind of abuse in mind. it doesnt make any sense.

[majik16106]

they make a fuss because the TURBO engine is built for TURBO appication and the NATURALLY ASPIRATED engine is built for NATURALLY ASPIRATED application.

the entire engine is built different. they dont want to waste the time and money on an engine that has no potential unless it is rebuilt with the proper

components when they can buy an engine that is designed with that kind of abuse in mind. it doesnt make any sense.

 

agree'd. ive always said the best way to go is to look at it that way. what was it basically designed for in the first place? if you have a 6 foot 5 200lb man thats pure muscle, and a 5 foor 10 guy who is 200 lbs of pure muscle and neither one had any sports experience and you wanted one guy to be a football player and the other to play basketball... which do you put where? i know its a loose analogy but i think it gets the point across. some starting out points are just easier. that being said though, this theory is predicated on knowing what the "purpose" of the build is. it doesnt make any sense to say one is better than they other if you dont know what its going to be used for.. and exactly what parameters he has to work with, some of the variables may make the difference.

 

integras arent the best thing for drag racing.. but they can go fast.

muscle cars arent the best thing for road racing... but they can with enough time/money.

BUt if you swap the two... your life is much easier.

[Gollum]

The irony is that what I believe to be the best turbo L series nissan made never came with a turbo....

 

My preference for a turbo build is the 81-83 NA engine. P79 head with flat top pistons giving a good and healthy compression ratio. The P series heads have good quench and the P79 flows almost identical flow numbers to the P90.

 

You can find those engines everywhere too, hence why it's my preference.

[Daeron]

Gotta ask, Why are they annoying? Because they make so much power so easily, because they get so much mileage, because they are so reliable or _____________?

 

Because enough Z-cars are stuck with four-speed transmissions already!

 

 

I have a question for all those who would prefer to stick with an "engine that was built for a turbo."

 

What makes an engine specifically built for a turbo? Pistons, combustion chamber shape, camshaft.

 

Sure, rod ratios and angles, piston speed play a minor part, but basically its piston quality and strength, combustion chamber shape (a function of the cylinder head and the piston crown) and the camshaft. Manifolds, fuel supply, engine management.. all of these are interchangeable things.

 

Turbo SR20s were not available stateside, to the best of my knowledge. So you want to import your special turbo engine. What makes it so different from the SR20s available stateside? Is it a different cylinder head? different pistons, rod length, what? I know they are slightly lower compression, but that can be achieved a number of ways.

 

My point is that you use what you LIKE.

 

I am looking at possibly getting a free 88 sentra with an E16i (TBI, 70 horses of augh!) My heart is set on swapping a GA16DE into it. You know why? I LIKE the thought of getting myself into a nice 80s nissan with a simple, reliable little DOHC 1600 under the hood. My Z is going to stay with a L-6 no matter what, because its what i like. (especially that solid valvetrain noise, oomph!) In fact, I may go to great lengths to bore it out, obtain a Japanese/australian market crankshaft (L20A) and DE stroke it just to find out if I would like THAT.

 

If you must use something for reasons so obtuse as "Well, it came from the factory with a turbo, so they must know what they are doing!" then please at least refrain from explaining to other people that they are foolish for going with their motor for reasons of their own.

[whitechocolatelove]

see its nice to have a higher compression engine but whats the advantage? all you have to do is turn up the boost on a lower compression engine to make the same power. see you can turn down the boost but you cant turn down the compression. and as to why the turbo engine is better like i said before it is BUILT for the app. in other words not only are the internals built for that but the block and everything else is also. it really doesnt make any sense to waste money on something when you can buy whats already available. pointless.

[datsun 1/2 dozen SD]

i currently have a 73 with an l28 f54 bock p90 head with .30 bore and flat top pistons. hks 1mm head gasket. it is still running the orignal su carbs from when we swaped it to an L28. its a 5 speed and a stock rear end.

 

but the true question is. since i already have the block bored and flatty pistons to build of my existing l28 and supply it to a turbo fuel injection setup or do i swap into sr. the only reason i am asking this question is that i already have the engine in my car and may save money but it also may be more headache .

 

i want the most bang for my buck and want at least 280 hp plus!

 

any insite?

 

 

 

 

 

 

dude sr aint even all that you could make pretty good horse power for cheap with the L28et if your mechanicly inclined you could do alot since you live o side therse a ecology there sometimes they got some good stuff there but you gotta go to chula vista for a bigger selection

[Daeron]

see its nice to have a higher compression engine but whats the advantage? all you have to do is turn up the boost on a lower compression engine to make the same power. see you can turn down the boost but you cant turn down the compression. and as to why the turbo engine is better like i said before it is BUILT for the app. in other words not only are the internals built for that but the block and everything else is also. it really doesnt make any sense to waste money on something when you can buy whats already available. pointless.

 

Wow... and I thought being short a couple cylinders was only literal.

 

Connecting rods, and the short block, all have a certain point beyond which they will explode. That point is expressed in horses. If you can make a given engine to 500 horsepower on stock internals, nut not to 600, then it doesn't matter if the engine is making 600 turbo or 600 NA, the engine blows up. Simple. Rods, block, and cylinder head all fall into this category; no matter what the induction, they have a threshold beyond which they BREAK.

 

You seem to be arguing that, straight out of the box, the SR20DET makes more power than the KA24DE; yah, no duh. However, if you want to go beyond 400 horses, chances are any engine you pick, whether its the L6, the KA, or the SR, you will need WORK done.

 

At that point, there are only two MAJOR differences to be seen between these three engines: Cylinder head combustion chamber shape, and cylinder head port shape and size. Once again, the less primary factors like rod length to stroke ratio come into play, but nowhere near as majorly as the combustion chamber shape, and the ports' shape. Camshafts and pistons pretty much all need to be custom beyond here, and stock rods would need to be prepped. From what I understand virtually all stock Nissan rods (at least on their "better" engines) are VERY robust; 600 on a 30 year old L6, and about the same on the more modern 4 cylinders.

 

Once again, I must reiterate, these engines are each DIFFERENT. NONE of them are "better" in any way shape or form than any other, UNLESS you want to compare straight out of the box stocker engines.

 

If you can't understand why that is, you need to open your eyes and pay more attention to the details I am trying to explain to you, rather than try to continue arguing your theory that an SR20 is a superior engine for boosting applications because SOME of them came from the factory with a little turbo bolted on the exhaust manifold. I say that with absolutely no venom whatsoever; I MEAN that. You need to put a little more effort into understanding how these things (internal combustion engines) work.

[240z!!!]

everyone has fail to mention the big part....we are talking about a z car not the 240sx so the ka would have to be bought...

 

ka 2.4 ltr. dohc na (i dont think any one wants a sohc) makes 160 horses

sr 2.0 ltr. dohc turbo (specifically built for turbo) make 205 stock horses

l28 2.8 ltr. sohc (na and turbo are built the same except the heads...unless you have the p79 block which came with flattop pistons....not to mention this is 30 year old technology and is limited in flow....there is no replacement for displacement except money....

 

id say it cost 300 or so for a ka including tranny thats low mileage b/c everyones jerking them out for sr swaps....parts are easliy avaliable and quite cheap....but you would have to have everything to turbo it and tune it so lets just say it was built well for 1500 thats 1800

 

sr now i got my whole swap for 1000 thats everything needed to straight drop it in and go (in a 240sx) but if you just buy one from a company you could get a decent deal on one for 1800 shipped (thats for the older redtop) now include mounts and a custom driveshaft, if your good with a welder you could do the mounts and wiring yourself...if your not then thats big bucks$$$$....

 

now the l28's are cheap....well unless you already have a 280z then you already have 1....but this is 30 year old technology....parts are considerably more expensive because of age....but it already has decent potential and is a straight bolt in.....but the big disadvantage is it doesnt have a crossflow head which limits the motor even more...

 

now all are decent motors....can easily reach anywhere from 200-400 horsepower but after that are limited.....now if you want to stay in the nissan family and have good power go get a rb26 and be done with it....or just make a rb30dett and then laugh whenever someone argues about which is better the ka or the sr......

 

but in all serious it is funny as h*ll to beat a corvette and then see the look on there face when you say its a 4 banger....priceless

 

but im not hating on any motor b/c ive had all of these sometimes theyre a hit or miss...ive seen someone throw a ka-t together in one night and run it ragged for years then again ive also seen ppl strickly build them up and blow them three months later....same with the sr's....id honestly say go with a l28et or a rb for simplisity.....sorry so long of a thread

[Gollum]

see its nice to have a higher compression engine but whats the advantage? all you have to do is turn up the boost on a lower compression engine to make the same power. see you can turn down the boost but you cant turn down the compression. and as to why the turbo engine is better like i said before it is BUILT for the app. in other words not only are the internals built for that but the block and everything else is also. it really doesnt make any sense to waste money on something when you can buy whats already available. pointless.

 

High compression means more power off of boost, and boost comes on sooner once you put your foot down. You can still make the same max power in most cases as long as we're not comparing a 10.5:1 compression engine to a 12:1. Get that high and detonation becomes a problem on most engines.

 

But in a case like the L series engine, the turbo version is almost as identical as possible to the NA engine. The NA engine can take just as much turbo boost HP as the turbo engine. Same crank, rods, piston material (turbo is dish, NA is flat top), cylinder head (almost idential), etc.

 

I know you're probably talking about how a SR is built for boost and the KA isn't. But I'm just showing how in the L series the NA engine is better for building a boost engine. And I could build a 300HP L series for less than you could do a SR swap, or get a KA swap done and turbo it.

 

I'm not saying either the KA or SR are bad. But if you're on a tight budget like most people in the real world, the L series kills most engine options unless you want HUGE power numbers, then a V8 is more practical.

 

everyone has fail to mention the big part....we are talking about a z car not the 240sx so the ka would have to be bought...

 

ka 2.4 ltr. dohc na (i dont think any one wants a sohc) makes 160 horses

sr 2.0 ltr. dohc turbo (specifically built for turbo) make 205 stock horses

l28 2.8 ltr. sohc (na and turbo are built the same except the heads...unless you have the p79 block which came with flattop pistons....not to mention this is 30 year old technology and is limited in flow....there is no replacement for displacement except money....

 

id say it cost 300 or so for a ka including tranny thats low mileage b/c everyones jerking them out for sr swaps....parts are easliy avaliable and quite cheap....but you would have to have everything to turbo it and tune it so lets just say it was built well for 1500 thats 1800

 

sr now i got my whole swap for 1000 thats everything needed to straight drop it in and go (in a 240sx) but if you just buy one from a company you could get a decent deal on one for 1800 shipped (thats for the older redtop) now include mounts and a custom driveshaft, if your good with a welder you could do the mounts and wiring yourself...if your not then thats big bucks$$$$....

 

now the l28's are cheap....well unless you already have a 280z then you already have 1....but this is 30 year old technology....parts are considerably more expensive because of age....but it already has decent potential and is a straight bolt in.....but the big disadvantage is it doesnt have a crossflow head which limits the motor even more...

 

now all are decent motors....can easily reach anywhere from 200-400 horsepower but after that are limited.....now if you want to stay in the nissan family and have good power go get a rb26 and be done with it....or just make a rb30dett and then laugh whenever someone argues about which is better the ka or the sr......

 

but in all serious it is funny as h*ll to beat a corvette and then see the look on there face when you say its a 4 banger....priceless

 

but im not hating on any motor b/c ive had all of these sometimes theyre a hit or miss...ive seen someone throw a ka-t together in one night and run it ragged for years then again ive also seen ppl strickly build them up and blow them three months later....same with the sr's....id honestly say go with a l28et or a rb for simplisity.....sorry so long of a thread

 

The L series head sucks because it's not crossflow??? Go read up young padawan. The L series head isn't that great due to completely different factors, like valve angle, port geometry, etc. The valves are closed for nearly a whole stroke in almost every engine. The air doesn't care weather it leaves one side or the other. If you remade any of the L series heads to be crossflow and didn't change a single thing, you wouldn't gain a single HP. The fact the intake and exhaust are on the same side only hurts power when it comes to the fact the exhaust manifold tends to heat up the intake charge, but there's ways to minimize that to a negligent degree.

 

There's guys that have made over 300HP NA on 3 liter L series engines that were reliable enough to be street driven for extended miles. In low life expectancy these engines have been known to make over 350HP NA. Those are some decent figures for such an "old tech" design.

 

I agree the cylinder head isn't the greatest out there, and a better design would be nice. But let's get our facts straight as to WHY.

[Clifton]

Someone brought up an L. Torque is a big factor. A Z with a 300 hp SR20 turbo vs an 300 hp L28 turbo or 15 psi vs 15 psi. The L28 will be faster, have more torque, broader power band, and be easier to drive. This can also be said for a KA vs SR.

[Nismopowered]

Cool! Another worthless sr/ka debate! Thought I got rid of this crap when I sold my Sentra! Displacement has no equal. You increase the effective displacement with boost. As far as wether the ka/sr is better, they are built for differnt things. The ka was built for more torque for a heavier car. The sr is built for top end. Sorry but the sr20det block will hold more powere stock than the ka, proven so many times. Dont you think there is a reason Nissan doesnt use the ka for racing? Yes the ka is a good motor but an sr will out do it. sr's have run over 700hp years ago with jun. What makes me laugh is the quest for power. How many people here really need over 250? And yes I have tuned ka's, Had the first Fmax kit for a true DET with over 300hp as a daily driver. Well ill just stick to a 2.8l with the tripples and exhaust, runs good and sounds great. And before I get flamed, I dont care! I was turboing sr's over 10 years ago before some of were even driving!

[Daeron]

Well ill just stick to a 2.8l with the tripples and exhaust, runs good and sounds great.

 

A man after my own heart... Mikuni, Mikuni, Mikuni!!!!!

 

Isn't there a rule here about having "bests?"

 

 

THE RULE IS, THERE IS NO BEST!!!!!

[PanzerAce]

A man after my own heart... Mikuni, Mikuni, Mikuni!!!!!

 

Isn't there a rule here about having "bests?"

 

 

THE RULE IS, THERE IS NO BEST!!!!!

 

Did somebody say Mikuni

[240z!!!]

The L series head sucks because it's not crossflow??? Go read up young padawan. The L series head isn't that great due to completely different factors, like valve angle, port geometry, etc. The valves are closed for nearly a whole stroke in almost every engine. The air doesn't care weather it leaves one side or the other. If you remade any of the L series heads to be crossflow and didn't change a single thing, you wouldn't gain a single HP. The fact the intake and exhaust are on the same side only hurts power when it comes to the fact the exhaust manifold tends to heat up the intake charge, but there's ways to minimize that to a negligent degree.

 

There's guys that have made over 300HP NA on 3 liter L series engines that were reliable enough to be street driven for extended miles. In low life expectancy these engines have been known to make over 350HP NA. Those are some decent figures for such an "old tech" design.

 

I agree the cylinder head isn't the greatest out there, and a better design would be nice. But let's get our facts straight as to WHY.

 

go to a car dealership....go pop all the hoods in there and tell me how many have crossflow heads and how many dont? you kind of contridicted yourself b/c port geometry....has a whole lot to do with crossflow or non....noncrossflow limits everything...how you make your ports the angles it even limits you on how much you can bore out the ports cause they have to make the water sleeves thinner to fit in the intake and exhuast ports on one side....you can only squeeze in so big of a port....unless you have a foot tall head....come on they make honda 4 banger motors that make 200 hp stock without a turbo...and everyone of them are crossflow....

 

heres an example...(im gonna make an imaginary head) say you have a completely blank p90 head...(i dont know any of the exact dementions so im just gonna throw some numbers out for my example)....say the head is 120mm tall..now if you have it non crossflow you cant have the ports touching so you have them say 20mm apart and say the water jackets are 10mm thick inside the port....lets not forget that they have to be centered away from the top and bottom(which really really limits the port angles and geometry) lets say 20mm...so you can only make your port hole size 30mm apiece and can only port it out safely to 35mm without busting through the water jacket....not including the port angle and geometry being forced to be one way from lack of space....

 

or

 

lets say you have the same 120mm p90 head thats crossflow that you could make your port angles and port geometry any where you want because you have all this space thats not been taken up from other set of ports....and lets just say the port size is 60mm with a water jacket of 20mm inside the port with 20mm of room on top and bottom so its exactly in the middle....so you could bore this heads exhaust and intake ports safely out to 70 + and be ok.....

 

all this is also not including the shape and geometry of the intake and exhuast manifolds being also limited because of space on the noncross flow head.....and can be made to almost unlimited posiblities on the crossflow (the almost stands for how much money your willing to spend)

 

which one do you think you could pull more power with?

 

again im not trying to hate on this motor....but then again its 30 year old technology....back then this was the 2jz of the motors but now its not...life goes on...(end of rant)

[Daeron]

go to a car dealership....go pop all the hoods in there and tell me how many have crossflow heads and how many dont? you kind of contridicted yourself b/c port geometry....has a whole lot to do with crossflow or non....noncrossflow limits everything...how you make your ports the angles it even limits you on how much you can bore out the ports cause they have to make the water sleeves thinner to fit in the intake and exhuast ports on one side....you can only squeeze in so big of a port....unless you have a foot tall head....come on they make honda 4 banger motors that make 200 hp stock without a turbo...and everyone of them are crossflow....

 

heres an example...(im gonna make an imaginary head) say you have a completely blank p90 head...(i dont know any of the exact dementions so im just gonna throw some numbers out for my example)....say the head is 120mm tall..now if you have it non crossflow you cant have the ports touching so you have them say 20mm apart and say the water jackets are 10mm thick inside the port....lets not forget that they have to be centered away from the top and bottom(which really really limits the port angles and geometry) lets say 20mm...so you can only make your port hole size 30mm apiece and can only port it out safely to 35mm without busting through the water jacket....not including the port angle and geometry being forced to be one way from lack of space....

 

or

 

lets say you have the same 120mm p90 head thats crossflow that you could make your port angles and port geometry any where you want because you have all this space thats not been taken up from other set of ports....and lets just say the port size is 60mm with a water jacket of 20mm inside the port with 20mm of room on top and bottom so its exactly in the middle....so you could bore this heads exhaust and intake ports safely out to 70 + and be ok.....

 

all this is also not including the shape and geometry of the intake and exhuast manifolds being also limited because of space on the noncross flow head.....and can be made to almost unlimited posiblities on the crossflow (the almost stands for how much money your willing to spend)

 

which one do you think you could pull more power with?

 

again im not trying to hate on this motor....but then again its 30 year old technology....back then this was the 2jz of the motors but now its not...life goes on...(end of rant)

 

Ok, I cut the head long ways down the port to get a better understanding of the angle of attack. The 1st pic shows the stock port configuration. Disregard the notch at the port inlet as this is the injector cutout. You can see the port inlet is roughly 1.350" and the valve seat ID is roughly 1.525".

What I will do I run a 1.565"(1-9/16") end mill into the port and then smooth the transition. The necessary angle appears to be 17deg. At the port entrance I will make the inlet 1.625" by hand porting. This will allow for a good transition from 1.625" at the port inlet to 1.525" at the valve seat. Here is a pic of what I mean.

Below is a pic of the exhaust side of things, looks can be deceiving, but it does need some work.

 

you are welcome.

 

Now, how different would those ports look if they pointed opposite directions? Oh, wait, they DO. Those are sections of a P90 L28ET head. The exhaust port "slice" is simply flipped.

[Clifton]

What makes me laugh is the quest for power. How many people here really need over 250?

 

I think for some, 250hp or less isn't worth doing. I'm in that boat. For those that can be happy with A 10:1 power to weight ratio they will be happy. I need 5:1 though.

 

the KA has been used in racing, Trucks and SCCA GT2.