Ok so I'm building a d16z6, speedfactory no notch rods, vitara pistons, old school cx racing log manifold. Now my hp range is 300-400hp and I know my goal is reachable BUT what are some things to do and not to do?? I plan to run LS chevy injectors, walbro pump ect so I got the basics down. What about the head?? What's the max hp a stock head can handle? I though about stock cam and just upgrading springs & retainers since on another forum guys are revving out to 8-9k on stock cams with just upgraded springs an retainers.. also is it worth upgrading the intake manifold or run the z6 or swap to a y8?? I found a edlebrock but $300 I could use on other things for the motor. I'm all ears and would love to hear some of you D series turbo guys combos

 

Stock head flows well up to about 500 horses. Springs and retainers can help you rev to the moon but your cam won't make power that high. Ditch the CX log mani and get something better. LS Chevy injectors aren't nearly enough and I'm not even sure they'll work. *shrug* Any stock intake manifolds are going to bottleneck hardcore.. Consider that Edelbrock or something like it..
400hp.. Get cast pistons out of your head. It can happen, but very finicky. Don't do it. Lol! Get some forgies and sail..
Walbro 255 I presume? That'd work for 400. Grab the
GSS-342.. Good fuel pressure regulator, engine management.. My build follows..
D16Z6: Bored to 76mm, CP pistons 9.0:1, Skunk2 Alpha rods, ARP head studs, JE proseal headgasket, mild port/polish exhaust ports, comp 59300 cam, comp springs, OEM retainers and locks, Ferrea 6000 valves, supertech seals, Skunk2 pro series (ported) intake, skunk2 Alpha series 70mm TB, AEM fuel rail, Aeromotive adjustable FPR 1:1 rising rate, -6AN fuel lines, 750cc injectors, Walbro Hellcat 525 fuel pump, Hallman pro MBC, Go-Autoworks miniram manifold, 3" DP, Tial MVS 38mm wastegate, Garrett GTW3476 turbo, 2.5" intercooler pipes, vibrant 12180 intercooler, Action clutch stage 3, HAmotorsports ECU with Demon2 board and Neptune RTP.
Might be some little **** missing here and there but eh.. I've tuned it myself and this is on 93 pump gas DAMN near, if not JUST over 400hp, and she has more to give. Limiting factors right now is block reinforcement and injectors. With larger injectors and E85, I could see 500 easy. That's REALLY pushing it on stock sleeves bored out this far..

 

don't bother with that cast iron manifold. Go with tubing style (mini-ram, ramhorn, top mount, etc). One thing you did not mention...what turbo are you going to be using? Please DO NOT SAY Ebay, CX Racing, Emusa, whatever.. Those Ebay turbos ARE GARBAGE.

 

the cast manifold with be staying as it's what I have, and turbo I'm leaning towards a holset since there some what easy to find and can support what power I'm after..

 

why are cast pistons finicky?? I see ycp pistons have been pushed way past there limits, I mean speedfactory has built some nasty cars using the ycp an never had a problem. And yes ls injectors will work i think huntertuned sells them for like 200 and they flow 800cc+ if i recal. Reason I'm rethinking the edlebrock intake is that's $300 that could go towards a better cam, springs, retainers ect..

 

Risk it if you wish, I merely made a suggestion.

If the injectors work, awesome. More than just the flow that need to be considered though. Stock D intakes will struggle above 300 HP, even with a better cam. Open up that intake for better flow and be thankful! You're not gonna get 400whp cheap, my friend. Stock fuel rail and regulator will work if you wanna cut some expense. Skunk2 intake and 70mm TB PACKAGE DEAL are like, 400 bucks. Damn good deal. Jump on it with enthusiasm! Cams.. Still a few good options; Delta, rocket, comp, skunk2.. 262 or 272. Comp 59300 can utilize stock springs and retainers because it keeps power in around stock rpm range and you don't need to rev to 8k for anything. I get a little jittery at full throttle, 7000 rpm @24psi.. Wooooohooooo!! You looking for a fun street ride? What's your purpose? What's your budget?

 

car will be a street strip build, more like a weekend strip car, cam I had planned is the delta 272, also plan crower springs and stock retainers. My budget is $1-$2000, pistons an rods are already bought along with the manifold so thats covered. Like i said 300+ I would be happy with.. So I can get away with running the stock fuel rail and regulator??

 

Stock fuel rail and regulator, yes. My first build on the same engine (piston shown above), cost around 2300ish. I used "cheap" parts in places I could get away with; clutch and turbo kit, exhaust, stock head, cast pistons (Nippon). My timing belt slipped causing piston to valve contact while I was under boost, causing this crack shown above on 2 pistons. The dyno shop i took it to (which is now no longer in business) had it at 347hp. I am questioning that to this day as there are quite a few other folks I have spoken with that said their **** was off. I know dynos will vary but, these fellas were skewed WAAYY worse than mine. Lol! Taking to account the old build comparison with the build now, how the new build feels vs previous; there is a TREMENDOUS difference now. I would say the number was off by 100, easily. Anywho.. 2000 bucks is a limiting budget. That throws out any turbo kit that isn't Ebay or CX.. I babied my car; just street driven with some spirited driving when I needed to, and after I tore everything down, I saw it wouldnt have been long before it grenaded anyways.. I had a wrist pin beginning to seize, the turbo seals were looking due to go at any time, I am amazed my clutch was even holding, (flywheel pic below). This was only 3 months on boost for an XTD clutch "rated" for 350+ hp..


100% honesty and disclosure coming from a single cam builder; If you're looking for LIMITED reliability, $2000 can buy it, sure. What it won't buy is 400hp or strip-worthy components.

 

OP, don't cheap out on components that really matter, like the turbo, fuel injectors, etc. You will just be wasting money.

Stock fuel rail will be fine but at least upgrade the FPR. Go with a reputable brand like Aeromotive. As for your $2K budget, you might want to hold off and buy parts whenever you can.

 

I'd also recommend the Skunk2 Pro manifold and 70mm TB. You don't need anything bigger than that. Keep the head ports stock. To keep your budget down don't worry about cam, springs, or retainers yet. If you have extra $ at the end, upgrade springs and retainers. Keep your rev limit at about 7500 - you'll probably be nosing off on power around there. Spend the money on a dyno tuning session, good engine management, good fuel system (injectors and pump...the rest can be upgraded later), a good clutch, a good wastegate, a good turbo, and a good blowoff valve. I'd recommend spending in that order. Any money left, I'd go for a good FPR next.

 

already have a tuner lined up, will be tuned on chrome since that's what I can afford, fuel set up will be LS Injectors and a walbro pump

 

like I said injectors I will be running LS Injectors which from trading and talking to folks work GREAT, as far as a turbo a holset is what is my plan since there cheap and can handle the power I want to make. And that's my plan and what I have been doing is collecting parts here and there.

 

You've been told incorrectly. LS injectors are no larger or better than GS-R or any stock applicstion. they are 240cc. period. not large enough.

Some Holsets are better than others, depends upon what you got. but assume nothing..

If you fail to plan... plan to fail

 

Must have been told by the same fellas revving the D-series to 9k with a stock cam..

 

I think the OP is referencing CHEVY LS fuel injectors here TheShodan and NOT a set of B18B (Acura LS) fuel injectors. I am unaware of a stock set that is as large as the OP has claimed, so I am assuming that he is purchasing a larger aftermarket set. I still agree with you that this is a mistake in parts choice... one of MANY in my opinion of the OP's list of parts and intended choices, but that is another discussion entirely.

 

That's about 42lbs/min or about 430cc at 4Bar (58.8psi) of fuel pressure, no? As usual. On point ridiculous.

 

Aren't those peak and hold?

 

"Decapped" Chevy LS injectors are supposedly good for 800-1000cc. I have not input on how they work - just what I've seen folks talking about online. https://www.huntertuned.com/product/...fuel-injectors

 

It matters not if you have a resistor box or individual resistors. That's what we did back in the day, and it still works. In fact, the old 90's Accords ran Peak & Hold injectors from the factory. I still have my injector box on my 850cc Siemen Deka Injectors, and I haven't changed them in over a decade. Whether or not he has "decapped" injectors to me still isn't trustworthy enough. I can agree with that statement

 

Oh, for sure. I know DSM injectors require the resistor box as well. For using Chevy injectors, this just seems like too much work for iffy results..

 

I think you are catching on here Txdragon !!!

 

Lol! I admire the creativity, hell, I once used a Yukon fuel pump in one of my S13s but, there are other options that will work. If it's a matter of cost, may as well find some Ebay injectors. Lol! I've given my input on the direction and of my build for the originally specified power range.

 

I too have contemplated the decapped ls injectors. The injectors have a cap on them to make them more "drivable" I guess and to "tune" the flow rate by the manufacturer. I know some people buy them in bulk and then decap and flow test them to match them with others that flow very similarly, as the flow rate will be inconsistent from injector to injector. I know like you said Hunter tuned uses them a lot, he sells them on his website and they are all flow tested and matched. I've watched his videos and he does some weird and sketchy/cheap stuff. But he's been doing it for so long and on so many vehicles he's gotta be pretty reputable.

 

I will have to agree. Some of the things he does makes me question his knowledge and ability. But then again, I don't think there are much tuners out there in rural Wisconsin so that may be why he has a good amount of folks going to him.

 

I think he is cheap, but has such good experience being cheap that he knows what works.. For cheap.