L28ET Build

[Jflick20]

Hello all,

 

This is my first post, but I have been wanting to build a Datsun s30 for about 7 years and now that I have the funds and stability to start the build and I need some help. So I like the L-series engine and I think that's what I am gonna stick with. I was debating the RB25det but with the motor being almost 5-8K without the needed parts for the swap. I am gonna go a built l28ET with probably a 280z because those are already fuel injected. It would make the swap simpler 

 

I want to make a reliable 350-400HP with the L28ET with the extra funds of not going with the RB swap what are some necessary parts for a motor of this caliper. I know I need bigger fuel pump, bigger injectors, a T3/T4 turbo, proper intercooler setup, and an programmable ECU. I know that the p90 and f54 were over built for the time but should I go with forged internals? I am looking to spend about 6-7K on the motor.

[NewZed]

Here's some stuff.  Still relevant, but there's newer engine management now.

 

 

 

 

It came from here:

https://forums.hybridz.org/forum/90-l-series/

[Jflick20]

1 hour ago, NewZed said:

 

Thanks! I have read the first link a couple of times, I found it very useful. Do you have any tips on find a L28et motor or is buying a beatup 280zx turbo the best way to go about that. 

[NewZed]

If you browse around you'll find that the "turbo" motor is really only different in that it uses the P90 head, which has no liners in the exhaust ports, a J pipe, and a turbo exhaust manifold.  People have bolted the turbo parts on to either of the other NA engines and made them work just fine using aftermarket engine management.  

 

If you want to make 350+ HP you'll need aftermarket engine management.  So, all you really need are the J pipe and the exhaust manifold from a 280ZX.  There might even be aftermarket suppliers for those parts.  That's how I'd break it down.  Just see what you can find and started piecing things together.  If you find a whole car and the price is right, why not?   The rest depends on how deep you plan to go in to the engine.  Too many possibilities to make a recommendation.

 

Here's a member who has some opinions.  But, if you're like most people who start a project your plans will change along the way.  you just need a jump off point.

 

 

[Jflick20]

42 minutes ago, NewZed said:

If you browse around you'll find that the "turbo" motor is really only different in that it uses the P90 head, which has no liners in the exhaust ports, a J pipe, and a turbo exhaust manifold.  People have bolted the turbo parts on to either of the other NA engines and made them work just fine using aftermarket engine management.  

 

If you want to make 350+ HP you'll need aftermarket engine management.  So, all you really need are the J pipe and the exhaust manifold from a 280ZX.  There might even be aftermarket suppliers for those parts.  That's how I'd break it down.  Just see what you can find and started piecing things together.  If you find a whole car and the price is right, why not?   The rest depends on how deep you plan to go in to the engine.  Too many possibilities to make a recommendation.

 

Here's a member who has some opinions.  But, if you're like most people who start a project your plans will change along the way.  you just need a jump off point.

 

 

Thanks, I was wondering what the difference would be. I knew that the p90 came from the 280zx and I planned on doing a couple of things for engine management. I appreciate all the recommendations.

[AydinZ71]

As @NewZedmentioned, I’m just now getting back into the turbo L series world again after a 20 year hiatus. I have added a turbo to an L24 (twice) with independent EFI, and built an L28et as well. The only other consideration not mentioned by him are the pistons. The turbo pistons have the first piston ring further down from the crown. I believe the purpose was to move them further from the combustion gases since ring failure is much more common due to excessive heat caused by elevated cylinder pressures.

 

Aside from flowing better, the P90 will give you a CR around 7.5 on dished piston L28 block. This is also an important consideration. I blew both my L24 turbo engines due to a combination of detonation and high chamber temperatures (L24 ran an 8.6-8.9 for e31 and e88. Detonation gives you a dramatic failure, while high temps on cast/stock piston+ring combo will wear out over a matter of months. 
 

The key word here is RELIABILITY. If you want an engine that will last you 100-200k miles with your torque needs, invest in forged pistons with modern ring materials. The rest of the crank components will handle 350-400ft-lbs of torque no problem. If you get your hands on  a core L28, you can build a reliable engine for 6k. I recommend aftermarket manifolds (pro tuners for example) if you really want to hit the 400 mark. You can hit 300 with the stock manifolds @ 16-18psi but you will need a better downpipe. Look into 2.5” quality intercoolers (I am looking into water cooled), an indipendent EFI ($1-2k), and a quality turbo (Can’t go wrong with Garett). 
 

There are many little things you will need to change and upgrade as well, but that will get you started. For example, the stock 4 or 5 speeds start becoming unreliable at 300-400 ft-lbs torque IF (this is key) you actually can grip/launch in a low gear. If you are sliding all over the place (which you will without an LSD & soft, wide tires) the 5 speed will be OK. Mine lasted 8 years but I never had the traction. 
 

last thought: going above 400hp, an L-series starts to get expensive. You start to get diminish returns above this with the P90, even when it’s ported. It just doesn’t flow as well as it needs to. One primary consideration is an RB, LS, or VG/VQ/VR engine can be fitted with a reliable high-torque transmission without customizing a bell housing. 
 

 

 

[Jflick20]

9 hours ago, AydinZ71 said:

cast/stock piston+ring combo will wear out over a matter of months.

So from you having multiple L-series turboed motors would it be a waste to go with the L-series. I can spend the extra on an RB I love both engines I wanted something I can build and have something a little bit more bullet proof. My problem I think is I want some reliable I can take on the weekends and I know it will start and rip without a problem that's why I am willing to spend the extra on building the most built-proof motor. The HP numbers don't really bother me as long as I can run like 300 I wanna keep up with most modern engines :).  

 

9 hours ago, AydinZ71 said:

Aside from flowing better, the P90 will give you a CR around 7.5 on dished piston L28 block.

I have a L28 lined up with a roller so a L28 block with a P90 will yield the best results? I will end up going forged pistons and rings etc. 

 

My next question would be how friendly is a L-Series to build I know my way around a car and know quite a bit from my father but I have never taken apart a motor yet. I know there is a book I forgot the name of it but its like the manual for building an L-Series engine I will be using that as well and youtube is also gonna be very handy.

[AydinZ71]

Just to be clear, the stock pistons+rings MIGHT do OK with a low enough static CR. For example, I never ran stock L28 dished pistons with the P90. I believe there are folks on here who have and did not express ring wear issues. There just isn’t much margin for error. 
 

L28 dished pistons + P90 head is your best case. P90a is a great head but has hydraulic lifters which are expensive to replace. You are also unable to adjust lash, and therefore are restricted for the stock cam (again, OK for up to 400). If you go forget pistons, you will need to machine your cylinders and rings to tight tolerances. (Not a bolt-in swap) While you are at it, you can overbore. 
 

Think of the L-series as a “truck/utility” engine when comparing it to modern engines. It is extremely reliable, over-engineered (extra metal thrown everywhere), extremely easy to work on, forgiving, simple, heavy, and inefficient. 
 

RB25 is more efficient (big plus is DOHC), but I don’t believe the stock block components can handle that much more torque than the L-series. RB26 is a huge improvement on stock component reliability, but they are expensive and harder to find now. 
 

Is this going to be a daily driver? 
Here is just my opinion on what I would do. Remember, 1000 ways to skin a cat: 

 

300HP - L28et (if you have access to cheap L28 with a P90 head) for great torque and a lot of fun. You can even run a T3 super 60 and have pretty quick throttle response. 

SR20det for lighter and better handling at 300hp, but probably more money. I don’t have experience here.

 

F20C for even lighter and better handling track car (but not intending to be competitive in spec racing) at 200-250hp. 

 

400HP - RB25det + fuel, turbo, IC mods

 

500HP - RB25det with either RB26 internals or aftermarket components.

 

500+HP - just build an LS and consider some form of forced induction. 

almost any of these engines can make 500+HP, just with varying amounts of money and reliability. 

[Jflick20]

5 hours ago, AydinZ71 said:

s this going to be a daily driver? 
Here is just my opinion on what I would do. Remember, 1000 ways to skin a cat: 

No this is gonna be a car just for the weekend or to take for car shows etc.

 

Thank you for all the useful information, and will take alot of it in consideration. I like the fact of keeping it nissan with the build. I have a lot of thinking to do as far as what the exact route I want to take.

[NewZed]

Don't overlook the LSX engines.  Fairly lightweight and powerful.

 

And transmissions.  That's the other spendy part about more power and different engines.

 

And rear end.  Big torque and sticky tires and you'll want more back there.

[AydinZ71]

1 hour ago, NewZed said:

Don't overlook the LSX engines.  Fairly lightweight and powerful.

 

And transmissions.  That's the other spendy part about more power and different engines.

 

And rear end.  Big torque and sticky tires and you'll want more back there.

i agree. I mean... for anything over 250hp working from scratch, LSX is hard to beat for a cost effective build. The rest is personal preference and secondary considerations (like efficiency). 

 

Once you break your Nissan 5-speed, the only reliable upgrade I have found is a custom bellhousing for a CD00X tranny from a 350/370z. If you feel like breaking more trannies, they are practically giving away Nissan 4-speeds here in Socal. 
 

if you are not driving this every day, then fuel economy is not an issue and LSX makes sense. 

you will need to consider an LSD regardless, but especially starting at ~200ft-lbs (for a light 71’) you will not keep traction in first. Many options here, and all that are worthwhile start at $1000. You will find a handful of threads I started in the last 6 months on the topic. 

those of us keeping the L28et is for nostalgia/preference or we already have upgraded parts over several years.

Edited February 19, 2021 by AydinZ71

[AydinZ71]

Almost forgot... you will start wearing out the stock driveshaft U-joints (non replaceable) and diff front mount around 250+ft-lbs. I went through many driveshafts before having a custom one made. There is a great solution for the R180/200 front diff mount on the market now for about 100 bucks