Stroking it
 

If I were to purchase a stroker kit, or at least a crankshaft, what if any other supporting parts would I need?

Money isn't unlimited, but I am of the "buy once, cry once" mentality.

Power goal is around the 450 crank/380 wheel mark. A little short won't break my heart and any overage, well...the more the merrier. I intend to add the JWT cams and a Z1 ported manifold, also.

Thanks in advance, guys.

I would talk to Daelen @ MA Motorsports. Are you shooting for the 450 mark with or without forced induction? 450 NA hasn't been done outside of some Grand AM race engines that don't use the factory heads yet.

I wanted to stay NA. I know the flaming is coming from the boost crowd, but honestly I'm kinda throwing a number out. Maybe 450 is a stretch. I'm just thinking with what's in the Z1 400hp kit, cams, ported manifold, and a bump to 4.0L, I thought it seemed reasonable.

Right now the record is 360ish, and that was with a dry sump and a bunch of one-off parts. He was still a 3.7 but he was spinning it over 8k rpm on e85.

Anything's possible with a big enough wallet, but you might end up spending more than forced induction without all the torque.

If you bought a stroker kit, you'd likely need custom pistons since most buyers are using them with a turbo.

Ah, alright. So what could I realistically expect out of a NA 4.0? And wouldn't the longer stroke have more of an effect on torque than horsepower? Strictly for explanation purposes, but like how Corvettes tend to make the same horsepower and torque versus the Z being 330 and 270? I'm trying to learn and I just want something different. I know you've gotta pay to play in this game.

I don't care to spin it any faster or change compression, so could I keep the stock pistons and just change rods?

If you dont want to change compression or RPM then it aint gonna happen.

Now it can be done, with some hard work on your part.

My best NA motor made 111 hp/liter with two valves and no dry sump.

So, a 4.0 liter would make 444 hp.

Others have done better.

I can't maintain the 11:1 compression and 7,500rpm redline? I intended to add the Nismo oil pump, but more to cover all the bases than any intent to rev higher.
So where would compression need to be? And redline?

13.5 - 14:1 with E-85.

Need bigger cams to move more air so the power band will likely move up, like to 8500.

So, you are talking real outside the box parts and build.

Best bet would be to call an engine builder who has experience with this platform in the natural configuration, and get thier input.

You are going to need crank, rods, and pistons. The biggest thing is nobody know how much it is going to take to get to the 400hp at the wheels. You are looking at an easy 10k or more to build the motor and that is just for the motor. This is why most folks just say forget it and go FI. You may spend 20k and still not meet your goal.

I don't have E85 here. I'd have to stay w/ 93.

I'm not expecting for 400 to the wheels. Like I said, just spitballin numbers and the 450 crank made sense in my head due to reasons listed earlier.

I was planning for cams, but I don't suppose those would work with the larger displacement? Or would they?

I don't know of anyone on this forum has gone down the path you are proposing... as SG4247 said your best bet is to call up an experienced VQ engine builder. You'll get more answers in 10 minutes then you will in this thread over a month.

Even better, talk to them and report back what you find out. Next time someone is searching on this issue they may happen on your info...

I don't know much about engine builders (and building)... but I'd start calling around to some of the top tier Z shops like Z1 and Specialty Z... MAMotorsports has built some motors too and has a presence on this forum as well.

I'd recommend getting a ride in a 500+whp boosted Z before embarking on this journey (If you haven't already). You might find that the proven path will get you where you want to go.... It would suck to drop 20k for 400whp NA build and then get buyer's remorse the first time someone takes you for a ride in a forced Z.

Understood. I am by no means questioning the tried and true process, it's just that the idea of an NA build appealed to me more, but I thought that would be a nice extra bump over full bolt ons, but I was curious what would have to be changed to allow for the extra displacement.

There is a guy who has done an LS swap - that might be something that interests you as well =)

Haha not to be picky, but I really wanted to keep this engine. I've read over that thread multiple times and it's a sweet build.

I just wanted a little extra thump on this platform. The one off rarity of it also appealed to me and sort of makes me want to do it even more now.

So check my build which has a target of 500+ whilst remaining NA, but it is a full-race build based on JWT parts, non-VVEL heads which are mega CNC ported, 14:1 pistons with Bryant 4.0 steel crank

The new engine will go into the car after Xmas as we are only just now about to start the OEM engine with a Motec M150 tomorrow (7 Dec).

When we have the M150 running the EM engine, we'll install the new beastie and see where we get to.

The heads have sufficient flow to make just over 500 at the crank but it remains to be seen whether we can actually get that

Investment to date is 5 figures starting with a 2 ........ it is NOT cheap.

Be very careful what you wish for.

Best you speak with Clark Steppler or Ben Pila at JWT

http://www.the370z.com/engine-drivet...ine-build.html

Ok, this is definitely looking to be more than I anticipated. In my list of parts that I've compiled thus far, I had about $13k figured, but I thought that was a fairly safe estimation to cover everything.

I can't wrap my head around $20k plus for this. I sort of assumed that considering this wasn't going to be a high power build, I could keep the stock pistons. I know the rods would have to change to allow for the longer stroke, but I certainly didn't anticipate swapping at least half the internals.

Who should I contact about the crankshaft? I know there's a horror story or 2 floating around about the BC kit, but is that a recurring issue or was that 1 off problem from an otherwise reputable and trustworthy manufacturer?

Just for my reference what are the head flow numbers? i see the 304-310 numbers were they final?
Really interested in your results.

Email works as well.

Thanks

Update: I called MA Motorsports last week and talked with Daelen for 20 minutes or so and explained what I was thinking. He confirmed that on pump gas, there's just not much to be had with the extra displacement, especially when compared to the cost of the build. He did tell me it may very well be worth it if I could switch to e85 and raise compression to around the 12.5 mark, but that's not an option for me as the closest gas station with e85 is an hour or so away.

So, with that said, I have ART pipes in my spare bedroom and waiting on my exhaust. I'll be heading to Z1 just after the 1st of the year for install and tune, then on to saving the pennies for the suckerpunch oil pump and the JWT C2 cams.