Engine Build / Stroker before FI - Thoughts and Questions
 

So after a year or so of saving up money from work, I finally have the funds available for a forced induction kit. I had my heart set on the Boosted Performance kit, because I would be installing it myself and it seemed the easiest, as well as a very good performing kit, but I also took notice of the newly released GTM twin MHI turbo kit, which is priced so amazingly.

After a few back and forth discussions with a couple of friends however, I was also tossing around building and possibly stroking the motor before forced induction. I never plan to sell this car, since I already own a civic as a daily (d16 non vtec, what), and it dawned on me that if I could build and stroke the motor, I would have room for a crazy power build down the line. I also thought that if I were to stroke the motor with GTM's 4.2 / 4.5 kit, I would make a huge power increase N/A for the meantime, and that would hold me off till next year.

I know it's dreaming big, considering the prices listed on GTM's website for the stroker kit, as well as building the motor in general, but did you guys have any thoughts about what the costs and misc. stuff that would be required? Also, any thoughts on specifics like brand of forged internals, compression ratio, etc. Like I said, I will never get rid of the car, so I have plenty of time to figure out both saving up, as well as time that I'm without the Z.

My main concerns would be the cost of doing the stroker kit, as well as if the car would retain it's driveablity, so to speak. That would include VVEL working, as well as Synchro-Rev Match, reliability, and fuel economy. I drive my car like it's meant to be driven, so I want something that I can depend on. I figure a built motor will be more reliable than a stock motor on boost.

Any thoughts on this would be appreciated. I really do want to give this a serious try, if the price isn't crazy. I'll be calling GTM later this week. ^^ I'm kinda expecting that this is gonna cost a fortune. :icon17:

Why bother stroking it if you are willing to build it and go FI? Displacement will help you make more power, but the issue with stroking is going to be all the additional heat generated by the longer stroke as well as piston speed stress. If I had your budget, I would just build the engine at the standard displacement and hang some big Garrett turbos off it!

I agree with Nix. I think stroker is not worth it.

Would be more easier to build the motor and go with a stage 2 or 3 kit. You could also save big money building it yourself. The complete built engines on Gtm site seem priced really high.

Also built motor could be usable on the street. The only stroker kit I seem with FI is at like 1k hp. Must be extremely hard to plant that kinda power on the street.

I'm in south Florida also. If u ever finish this build I'd love to see it!
Good luck!

Oh yeah, of course. Plus if the block was sleeved, the heat would be crazy, I would need at least the CSF/Mishimoto radiator, possibly multiple oil coolers, mandatory meth injection, and hood venting. I wish my budget was a sky-is-the-limit budget, I'd dream of having the next 1k hp 370z. :icon17:

Mechanically speaking, stroker kits seem like they would be more prone to crankshaft failure than leaving stock displacement, correct? It probably also creates issues at high rpm, since piston speed per revolution must increase.

Mmhmm, the White Dragon Z, haha. The whole reason I thought of stroking the motor was if that maybe a deal could be worked out that it could be affordable enough, I'd love to invest in the stroker kit as well as a fully forged block, even if it took me until the end of this year to save for it.

Looking at GTM's website made me sick. :roflpuke2: It's so pricey! I'd definitely have a shop build my car for me, and just have parts ordered. I'm curious what goes into the stroker kits. AFAIK, no one besides the UAM car has one installed.

South FL, woop woop! I'm in Boca Raton myself. Where about in Broward are you? Maybe I've seen the car, who knows.
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Thinking about it, with my current funds, I'd say if I needed $8k or so to build the motor at stock displacement (at least without labor costs involved), I'd have to wait till around the end of summer or a little later to begin the build. To be honest, I haven't really built a car or owned a car with this much capability as the Z before, but I live by the adage that you do things right the first time, rather than cheaping out. :tup: I really wanna do this car right, and I sure do have plenty of time to figure it out. ^^

But, that being said, looking on GTM's website, the stroker kits are priced at $6k, and include the crank, rods, and pistons. Separately, what do you think they would run without a stroker crank?

I read an older thread about how much an engine build costs, hypothetically speaking, but there weren't really any concrete answers, let alone ballpark figures. Any thoughts?

I'm in Sunrise now. I'm boosted also. 540hp/500 tq.. Already difficult to plant this power down.. But I'm stanced also lol. I've been in HIN car show that was at Miami beach convention center and few others if u go to the shows.

Cost on a full engine build? I'd say around 8-10k. Maybe less if u do it on ur own.
I've dropped some good coin in my ride so far. Built motor is my last thing on the to-do list. So far I'm enjoying the ride so I'm not in a rush. I'd say I dropped about 15-18k so far. ****, don't remind me!

GTM is making a v8 swap kit (or w/e they wanna call it). Oh the badassery. Going for a stroker kit will be cool and all, but if you plan on doing FI later, compression would be lower than a NA stroker. But I agree with the others that a good FI kit is a better purchase. You can remove that and sell it, increase power with a touch of a button, it's cheaper, and faster to install and go.

Very nice! That's actually exactly the same numbers my original goal with FI was, give or take. It honestly must be a blast to have that much power, haha. Do you ever go to the towers meets on friday? I don't know of any others really down this far south.

I was at HIN. ^^ Didn't make the roll in though, couldn't plan logistics with the girlfriend and all. I had a few friends with Team Sunworks and a buddy who had a car at the HPLogic stand. Only other show I recently went to was in Daytona, which was Simply Clean. Do you have any pictures of the G?

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But anyhoo, considering the motor build, I was thinking around $8k, which may be a lot, but in the long run, that will hold all the power I need. When you mean do it yourself, do you mean at home kinda-thing? I didn't really think it was possible. :ugh2: All the work done on my car was done by me, and I'm never afraid to try new things, but is it actually possible to build the car in my garage? I store my car in a one-car garage at home, and just drive the Civic to work and school, so it's no pressure if it just sits on stands for weeks or months even.

Considering having a shop build it, I know HPLogic does lots of stuff with Z's, and they are in WPB. Rev Works is a member on this forum too, and they are in Orlando I believe. Still though, I'm treading very shallow waters when it comes to engine work.

I'm doing almost the same thing. I've talked with GTM about their 4.2L upgrade. I was told to avoid the 4.5L due to what they have to do to the engine and could be a pain...meaning it's really for tracking and not DD. I'm going to buy the whole engine including the block. That way I have a back up engine and they run about 16k for the whole engine but it's rated for up to 800hp. Oh choices.....when your done pulling your hair deciding which way to go let us know and good luck with your build!!

Well lets lay down your plan:
-What do you plan to do with the car?
-Do you want more low end power or more of a go for the HP king?
-Do you want DD reliability & driving or purely focus on weekend toy?

You have no idea how badly I'm thinking about pulling the trigger on ordering a kit. :icon17: Considering the compression, I know guys that build them drop the compression, and I was thinking about 9:1 or even 10:1. Of course, it's all speculation, I'd have to talk to GTM or someone with experience about it.

Bet you can't wait for the twin SC, by the way.

Hmm, interesting. I wish I could swallow the cost for a long block, haha. I'll be calling them hopefully tomorrow if time permits, and get some more concrete information. 800whp is auch a nice number. ^^ Go big or go home, right?

Thanks for the support, by the way!
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If I had a shop build my car, I would probably also at that time have a clutch / flywheel installed too, so that's about another grand in parts. Hopefully I'll be able to follow through with all this, I really want to get this build started!

Good questions that will help us answer.


OP, you might also look at ditching the VHR heads if you have big plans. Much easier to accomplish big power reliably without VVEL.

I really plan to drive the car for myself, possibly participate in HPDE or drag strip type stuff, but it's mostly for me. My dream ever since I got into modifying cars was to have a full interior car with leather, ICE, AC, the works, that looks great on the exterior, full suspension mods and whatnot, all while having a crazy amount of power. I don't plan on stripping the car out and becoming a race car. :driving:

Honestly, I prefer a balance of power, I'm not looking to be a dyno-queen or anything. I feel with a larger turbo kit, I could make pretty good hp and tq numbers, and it won't become an all out HP race. Or should I? ;D

I'm kinda weird on this point. Where it stands now, I drive the Z irregularly as a day car. Most days, if I'm just going to work or school, I'll drive the Civic, but some days I just take the Z for thr whole day, or if I'm going to a car meet or something. Heck, some days I run home and switch cars halfway through the day! So I'm definitely looking for some DD reliability, since it's not strictly a weekend toy.

HP KING!!! I hope...

I remember seeing that someone was doing an HR head swap - did that ever go through?

Thinking about now, I don't think the stroker kit, let alone any internals kit should affect the heads in any way, right? Maybe the VVEL could be tuned in conjunction with the increased piston speed, alongside timing control for some good power gains.

VVEL tuning is still in the beta phases and only pro tuners have access currently. They could tune it for you but might be best to wait for more information to come out.
On your build, I would skip the stroker kit as it would be a waste. Focus on building a reliable engine that can achieve the power & performance you want/need. Be that power under the curve, very specific HP/TQ, etc.

A good starting place is: http://www.the370z.com/forced-induct...ld-thread.html