What are the pros/cons of building a turbo stroker motor?

[mrcheeze36]

Hi All. I'm building an L28et and was wondering if I should build a turbo stroker or concentrate my efforts on other areas (individual throttle bodies, etc.)?

 

I will be getting an engine management system, T3/T4 hybrid, intercooler, etc.

 

This will be a daily/weekend driver (more towards weekend) and I'm looking for lots of power, with reliability in mind!

 

Thanks!

[Guest bastaad525]

well I'm no expert... but built a couple engines and learned lots of lessons the hard way which anyone here will back me up on that! so here's my .02c

 

 

Pros: hmm... well, torque off boost would be higher, so, I guess it'd be a better driver on the street when you're just cruising around at low rpms... But, that would also depend on what compression ratio you built it at, which will depend on what type of fuel management you want to run, etc. One of the disadvantages of a stock block and head, is that it's got some absurdly low compression ratio, like 7.5:1, which makes it a slug off boost. But is that really that big of a deal?

 

Cons: Cost... stroker motors are NOT cheap to do right, and every writeup I've read says they also take a lot of time and work to put together. Unless you have a well outfitted garage and are going to be doing the work yourself, and have lots of spare time. Really... to me, any power gain you would get by upping the displacement just isn't going to justify the amount of labor and money involved, when you could just take a stock block, and with the money you were going to spend on building the stroker, just buy better engine management, injectors, turbo, and intercooler, you could then easily run enough boost to put down a lot of power, very reliably. More than 300rwhp is not uncommon. Why I know some guys do it just to be different, or because they really want the most performance they can get, or whatever, but for me... why take the hard road when you can get the same results the easy way?

[mrcheeze36]

I appreciate the advice. I just wanted to get great power through all rpms.

 

I will get all the goods (emgine management, intercooler, injectors, etc.) regardless if it will be a stroker or not, I just wanted to see if I will be getting better results with a stroked engine with the same turbo mods, without sacrificing reliability. It'll be an entire engine tear down and build (forged pistons, etc.) and my friend (builds race and rally engines for a living) and I should start working on it within the next few month.

 

Once again, thanks for the great advice!

[Scottie-GNZ]

Depends on what you mean by "lots of power". Considering you plan on using a hybrid turbo, use the $$$ you would spend on a stroker and put it in quality components that prevent detonation and allow you to increase boost safely to make the HP. Even with a stroker you are going to need those components anyway so the extra HP and torque that you gain from a stroker might not be worth it if your HP goals are "reasonable".

 

I know folks will argue that the stroker's torque is a big advantage but a well setup L28ET puffing 20psi boost has enough torque to make the stock suspension and even the best street tire scream "Uncle!". I could be wrong here, but I would venture a guess that 1 out of 3 strokers I have heard of have some sort of problem with pistons/rings, shoddy machine work, etc.

 

I say freshen up the shortblock with rings and bearings, do some light porting on the heads, spend the money on quality bolt-ons, an engine management system and do not go cheap with octane or try to run lots of boost on pump gas.

[jgkurz]

If I had it to do all over again I would have kept the stroke stock and put the money into the cylinder head work.

 

In my opinion, you need longer rods (longer than 133mm) to get the rod/stroke ratio where it needs to be with a stroker. That's 1000.00 by itself.

 

Don't get me wrong, my stroker is fast, but there are more than a handful of stock bore and stroke L28's that are making much more HP and torque than I am.

[Warren]

It just so happens that I'm in the process of building one myself. Kind of a "while I'm at it" project that got WAY out of hand, and you guys are right, it IS expensive.

 

It all started with the desire to fix an exhaust manifold leak caused by 2 broken manifold bolts. the foremost and rearmost on the head. After removing the head, because evidently the previous owner tried to remove the rearmost one and ruined the hole, I decided to go ahead and rebuild the head..."while I was at it". Of course I went overboard and replaced everything except the cam and rockers.

 

Then came the block. Since I had the head off, the block looked like it needed attention too, due to aparently leaking freeze plugs. Well, as it turns out, unbeknownst to me, the #5 & #6 Piston skirts were in the back of the oil pan. Here we go again. Since I had to have the block bored and pistons replaced, and I knew where a perfect LD28 crankshaft was, I figured "while I'm at it", I might as well stroke it too.

 

After doing alot of research on how to go about doing it right, and hearing alot of horror stories about previous attempts made by others, I decided to work out some figures and come up with my own combination of parts. Here is what I've come up with and am using in this build.

 

F54 Turbo Block

LD28 Crank

L28 Rods - NOT L24

Custom Dimension Forged Ross Racing Pistons (87mm Flat Tops)

Sealed Power Rings, 2mm 2mm & 4mm...Spaced and Moved down the piston slightly

P90 Head and

Nissan Stock Head Gasket

 

There is alot of math and dimensions to work out in doing this, but "while I'm at it", why not...(got me again). Needless to say, the custom pistons have been ordered and will ship on March 1st.

 

The piston design and specs were gone over with Ross Racing Pistons over a couple of hours on the phone and it was determined that, based on the calculations of the dimensions of all of the parts involved above, the compression ratio would be 8.31:1. That is just a tad higher than the previous calculations using the L28 Rods and LZ22s Pistons, which according to the chart provided by Jim Wolf Technology on the Z Club of Texas website, was a viable combination. It's been determined that stock LZ22S Pistons were not strong enough...the ring lands won't take the turbo charging.

 

By the way, if you're interested, I need 1 more person to buy into these pistons to make it a group deal and all buyers save $125 off of the total cost of each set of pistons, pins and rings in the custom piston order. PM me if you need info.

 

I've also been bitten by the non-programmability of the stock Nissan ECCS in the 82 ZXT and the desire to utilize the above listed motor more efficiently...so out it came, and "while I'm at it", I'm installing the SDS EM4-6F distributorless standalone system.

 

Next is the turbo. I just got a wild hair up my wahzoo to do something about the little stock T3 that was on the motor. So "while I'm at it", I'm installing a new Turbonetics T03/T04E turbo also.

 

When I bought the car last March, I opened the hood and much to my surprise I found it had an MSA Intecooler kit installed on it that was not advertised in the sale description. This was in good working order but it appeared to be a little small, so I figured, "while I'm at it", I'd upgrade it too. I'm going with a new 24"x12"x3" Hybrid Intercooler with 2.5" plumbing.

 

Oh, and since the engine compartment was empty, I decided "while I'm at it", I'd take everything out and refurb it. The engine compartment was stripped of everything and re-painted. Every part, nut, bolt, washer and clip has been removed and bead blasted, painted or polished and is now sitting on the shelf awaiting the the engine reinstallation.

 

There have been several other mods made to this beast such as Tokico Advance Handling Package installation, Custom Fuel Rail, Ford 42# Injectors, Non-EGR intake manifold, 240SX Throttle Body, custom downpipe and 3" exhaust, just to name a few of them. There are alot more...too many to list.

 

Needless to say, this "while I'm at it" bug has infested my garage and it's a hard one to kill. After all this engine and compartment work is done, and the car is running, I get to start on the interior. Most of the parts are already here and on shelves as well. After that's all apart, the body work starts. Then it's going to the paint prison for a while and finally, I'll get to start the reassembly of the interior.

 

Sorry for rambling, but I thought the stroker idea was something that I would throw out there and take comments on....since it was brought up.

 

(And you thought bastaad525 posted LONG Stories...)

 

Warren

[Guest bastaad525]

Depends on what you mean by "lots of power". Considering you plan on using a hybrid turbo' date=' use the $$$ you would spend on a stroker and put it in quality components that prevent detonation and allow you to increase boost safely to make the HP. Even with a stroker you are going to need those components anyway so the extra HP and torque that you gain from a stroker might not be worth it if your HP goals are "reasonable".

 

I know folks will argue that the stroker's torque is a big advantage but a well setup L28ET puffing 20psi boost has enough torque to make the stock suspension and even the best street tire scream "Uncle!". I could be wrong here, but I would venture a guess that 1 out of 3 strokers I have heard of have some sort of problem with pistons/rings, shoddy machine work, etc.

 

I say freshen up the shortblock with rings and bearings, do some light porting on the heads, spend the money on quality bolt-ons, an engine management system and do not go cheap with octane or try to run lots of boost on pump gas.[/quote']

 

Just about exactly what I was saying

 

too much extra work, too much extra risk, and much better options of how you can better spend that money to reach your power goals safely and reliably.

[zolorin]

But come on this would be such a bad ass motor if you do it right and with boost (god bless the boost) sky is the limit on the HP (until you blow the block), but I do believe 500HP is feasable on the stroker

[Lockjaw]

Well no one seems to remember that most of the stroker folks were having damper issues too, which requires a BHJ or something equivalent. I like that damper, cannot wait to get it installed.

 

If you want a stroker, and are going with forged pistons, why not bore the block out to 89 mm, that should get you close to a 3.0 liter.

 

I have stock stroke, 240 rods, and custom ross pistons in mine. I have a 87mm bore, why I chose that is beyond me I should have gone out 2mm more. Anyway, my pistons are flat tops, and I can run about 18 to 19 psi on pump gas.

 

One other option, you could have the crank welded and offset ground, and pick up some stroke there. Not sure of the cost, I think that is what James did. Be sure to BALANCE everything.

[Warren]

Actually if you were to bore the block to 89mm, you're going 3mm over stock, making the cylinder walls kinda thin. The F54 block has extra webbing between the cylinders to assist in strenght. If there was enough reason to cast the block with those extra webs, then why on earth would you chance boring to 89mm? Anyway, the setup I'm going with will be about as close to 3.0 liters as you can get without getting scientifically critical. It will be 2960cc's...and boring to 89mm's would put it right at 3.1 being 3098cc's... If you did that, then you would have NO further chance of boring the block again if something were to happen to the motor.

 

All of the above numbers are from the chart that Jim Wolf Technology provided. Here's the LINK.

 

Warren

[Guest bastaad525]

that's another reason I dont agree with making a stroker... if anything goes wrong with that engine, the block is pretty much a loss. And then if you DO rebuild it, man you gotta go thru that whole process again? I say stay stock block, they are cheap and still pretty easy to find... the more custom you get, the harder and more expensive it gets to start replacing stuff when something goes wrong... which... doesn't something ALWAYS go wrong?

[pallnet]

if anything goes wrong with that engine, the block is pretty much a loss. And then if you DO rebuild it, man you gotta go thru that whole process again?

 

I have not built a stroker yet. I have had all the parts to make it happen a few times just something gets in the way money wise. My feeling on that is if I had to rebuild a stroked motor. I would have them balance it all again. With knowing that balancing is the key to a good stroker. I wouldn't go short on a rebuild.

 

There are some ppl out there running the turbo stoker and doing well with it. I see no reason why it can't be done if you have the funds to do it right and the homework being done to back you up..

[Guest bastaad525]

Even more reason why rebuilding one would suck and cost even more if something went wrong the first time... didn't know balancing was so important to building one so it never occured to me.

[Ben]

I too have been gathering parts for a TT stroker for a number of years now....

I have the F54 block, a fully ported & CC'd P90 head, custom TT exhaust & ported inlet manifold, LD28 crank, various length rods, 2xT28's, Racegate etc etc.

 

Will I build it? Perhaps....

Then again, perhaps I'll alter my N42/N42 engine & fit a set of forgies & the P90, upgrade the injectors from the E15T to the 550cc 13BT ones I have, screw in another bar of boost & take it from there.

 

But what to do with the TT manifold & Racegate?

Perhaps a set of GT-R T25's (I know the flange is smaller) and a very well balanced L24 might be the go. 8000rpm anyone? 8)

[speeder]

I went through this same decision process when deciding what direction to take when building my new engine.

 

Starting from an engine that is going to be completely built for turbo performance, the differences are:

The LD28 crank, and

L24 rods.

 

Everything else you do to build a performance engine is the same between L28 and L30/31, including machine work and forged pistons. There is big power to be made from stock bottom ends, but for durability and ultimate power capability you will need forged pistons, good head work, and exacting machine work including balancing. If you don't have an 89mm bore, there is room for boring - but I'll point out that if you're reboring your performance stroker, you're buying new forged pistons for 600.00 and up. Personally, I would do another block from my pile of spares, reuse my forged pistons, and be ahead of the game.

 

Whether the cost of the crank and rods is worth the extra displacement is an individual choice.

 

I opted for a 3-liter stroker because I already had the correct rods and the extra cost amounted to what I paid to get the crank, which added less than 10% of the complete engine.

[RB26powered74zcar]

The last thing you want to do on this set up in my opinion, is go 89mm or larger.

I went thru two F54 blocks before I got it right. The first stroker motor I built I used a set of forged pistons I traded for a set of tripple Mikunni's, that were 90mm. That first motor lasted 1,200 mi until I had anti freeze in the oil. I pulled it apart to find a cracked cyl bore.

 

I thoufgt it was a fluke, so I had a second block done up the same way and that motor lasted 750 mi.

 

I pulled it all down again and started looking for the reason to find, I could put a pair of channel locks on two different cyl walls and barely squeeze, and they both crushed. They were as thin as a peice of paper.

 

I belive if you bore a L6 block any bigger than 88.5mm, your asking for big trouble... on a turbo set up that is...

 

I now have 88mm forged pistons, and not one problem with cyl wall flex, or cracking...

[Ben]

Agreed, keep the bore as small as possible. The % gains of the extra displacement just aren't worth the risk of destroying your motor....

[Warren]

Which is the exact reason why I decided to go with only an 87mm bore. First off, if I could have done it with 86mm bore, I would have, but due to the fact of 139,000 miles on the original 86mm bores, my F54 was due for a boring anyway.

 

Now I had the option of only going 86.5mm but since I was boring anyway, and only 1mm at that, and I had an LD28 Crank available, I decided to go to 87mm.

 

Now I've seen others say that they had gone farther with other pistons and were having problems. I know of one person who went with an LD28 crank, cast 87mm pistons and L24 Rods, but they had to shave the piston tops. That put the rings too close to the combustion chamber for my likings and poses additional funds being spent. That in itself was enough to make me figure out how to use the L28 rods that I already had.

 

From all the research I've done, I've found that there are a couple of ways to go 87mm without posing such potential problems, one of which is to use forged pistons. As another precautionary measure in an effort to prevent ring land failure due to higher combustion pressures in the combustion chamber caused by turbocharging a stroker, is to move the rings down the side of the pistons slightly. Another is to use a wider ring, which poses a slight problem if you plan on keeping the bottom ring above the height of the connecting rod pin on the sides of the piston.

 

The calculations I've made and the parts I've chosen will give me the ability to use the LD28 crank, with L28 rods and custom pistons. Only going to 87mm bores, I'm not chancing weakening the walls as much as an 88 or 89 mm bore and still have room to do something with the block if I need to, should the unthinkable happen. This combination will stroke it from 2753cc's to approximately 2960cc's...closer to 3.0 Liters

 

Again, if anyone is interested in this combination, or would like to get in on the custom order, which would save you $125 off of the set of custom pistons, PM or Email me and I'll give you all of the specifics.

 

Warren

[Guest bastaad525]

Agreed, keep the bore as small as possible. The % gains of the extra displacement just aren't worth the risk of destroying your motor....

 

 

yep... so better yet just keep the stock bore and turn up the boost instead

[Mack]

interesting, very interesting..... so, what to do, what to do... Ive got this damned LD28 short block. there was some mention of rod/stroke ratio in this thread.... I have a cure! Z20E rods (152.5mm long) or Z20S rods(148.6mm). LD28 block, L20b timing cover and timing gear. only problem is I need to find a piston with a 33.5mm(if I use Z20E rod) or 37.4mm(if I use Z20S rod) pin height and I am looking at an 87 or 87.5mm bore. I know with a stock 280zx turbo piston +1mm I should be safe shaving .7mm off the top.... input anyone?

 

McAdam