Forums/Z31P/z31-performance-upgrade-forums engine-mechanical-aa/300+whp build advice
Imported from Z31Performance.com Forums{{#if:aprophet13| — original post by aprophet13}}{{#if:2015-04-01 09:14:43|, posted 2015-04-01 09:14:43}}{{#if:21| · 21 post{{#ifeq:21|1||s}}}}{{#if:/Z31performance_archive/forum/z31-performance-upgrade-forums/engine-mechanical-aa/24893-300-whp-build-advice.html|
Local archive: view archived thread on dev.z31library.com}}
aprophet13: (2015-04-01 09:14:43)
TLDR: 1985 300zx Turbo: want a 0-60 time of around 5 seconds and want to modify to whatever hp this requires. ~$2,000 to spend. Advice?
I am looking at a 1985 300zx turbo and have a few questions…
I intend on dailying the car mostly but have a '73 240z to cruise in when this is out of commission (swapped in a different L24 I6 with a friend so I have experience wrenching on cars, just not efi)
My funds would be split between this and the 240z so realistically my budget is around $2,000 not including the car
I don't like setting a whp goal since its kind of arbitrary due to weight/diff ratio/dyno/etc differences
I am looking for a 0-60 around 5.0 seconds (e92 335i, STI, 350z, etc range)
1) Is this realistic? Given my experience level (want to do all work myself), budget, and drivetrain
2) If so around how much whp is a good goal? I'm thinking in the 250-300whp range?
3) If that estimate is realistic then are these modifications sufficient?
My plans are as follows:
Basic maintenance(t-belt, plugs, wires, etc)
Stock bottom/top end
Stock Fuel system
Stock ECU
Either maxing out T3 turbo or installing an HY35 I have
MBC set to 15-20psi (what ever will net my hp goals)
Ebay intercooler/piping
stock intake
K&N intake filter w/ resonator removed
3" turbo back exhaust w/ hiflow cat
possibly MLS hg/ARP studs just for insurance?
I think I've been reading too much and have gotten a little over saturated. Some people say you NEED this or that, and I've seen too many conflicting opinions.
I've looked at TONS of dyno sheets and stuff on Z31.com/this forum's dyno section, but most of those guys are way over my output goals.
Sorry if I sound like just another kid asking what the minimum I can do for X amount of HP is, but I've read so many posts of people saying they made 300whp on stock ECU/long block/fuel system and am just wondering what is necessary/a good idea to upgrade to have a pretty reliable setup for my goals.
Thanks in advance!!
Adrian
300zxturboftw: (2015-04-01 12:17:38)
Fuel pump, injectors, turbo, intercooler, exhaust, intake. Should put you around 350rwhp for around 2g's or cheaper if you find a good deal.
Intercooler kits are about $200. Rx7 injectors. Walboro. Hx35. Custom exhaust or cm racing.
jaqattack02: (2015-04-01 12:26:33)
You should try to track down an NA block to use for this. The 9:1 compression is much more conducive to making power. On my NA block I hit 250whp on 10 psi on the stock turbo with plenty of room for more.
darryl rice: (2015-04-01 13:36:34)
With you looking for a better 0-60mph....nothing responses N20. I recommend a NOS brand wet system(100 shot) with all the trimmings $1000. MSD 6-BTM(boost timing retard) $300, non restrictive exhaust system $200-$400, K&N intake filter system or something similar $100-$150, a set of drag radial tires for the rear ($300-$400). This should give you 4.7-5.0; 0-60mph
300zxturboftw: (2015-04-01 14:10:44)
^
I think he would get a lot more use out of upgrading the components vs. adding something that will aid the system and run out.
Axel kain: (2015-04-01 15:12:22)
Basically with his current list, needs to add/adjust a bit.
Nistune, MS, or other ECU system will need to be used. stock computer will destroy your car with these goals. (DON'T use JWT junk)
Consider getting some sort of hotter cams. with stock heads, they help to open things up some!
ALSO consider, with a VG33, unopened, except for Z31, or upgrade cams, is a very worthwhile, and cost effective power making strategy.
ozzyrulez: (2015-04-01 16:12:46)
I made almost 400whp reliably on JWT junk because my Nistune junk wouldn't work lol. It is not the best option but it works well for a basic plug and play setup.
turbofedz: (2015-04-01 20:08:03)
I've had JWT for over 10years now with no problems at all.4bar program.m30 JWT program in the box waiting to be installed.
aprophet13: (2015-04-01 20:58:46)
A couple things:
1) I am trying to use the stock long block- I've seen plenty of people making even 2x my goals so I think its a viable option and will keep down time/costs down.
2) This car needs to pass CA smog which includes emissions and a visual test. This means I am kind of restricted in my modifications. Even tuning the ECU is "illegal" but they couldn't know that just from looking. Things like a custom intake manifold would likely cause a failure. Upgraded turbo they couldn't really notice. Things like that.
3) If I upgrade pump/injectors would that require a tune of the ECU?
The car comes with a CX racing intercooler (I'd just need the piping), an MBC, and I already have an HY35 I could throw on
Its dyno #'s like these that have me confused- I get that a RRFPR isn't ideal but if I wanted to make max 300whp would that be a sufficient solution?
Is a JWT 3 BAR just an FPR?
If I need to tune the ECU I think I'd go with Nistune just because I haven't heard great things about JWT and even that it can take 6 months to get an ecu back
REVISED PLAN:
Stock longblock (free)
stock ex. manifold w/ T3 or HY35 (free or $50 for oil feed line to HY35)
420cc injectors- top feed since I have the '85 so MB 420 or equivalent ($300)
Nistune (still a little confused about what exactly to purchase but I'll allot $500)
Upgraded MAF? Cobra, Z32TT
Walbro 255 ($120)
3" CM exhaust ($400 possibly less depending on shop)
2.5" intercooler piping kit ($100)
Intercooler(free)
MBC (free)
Max total: $1470
Could the other $500 cover dyno tuning?
irace911: (2015-04-02 00:13:31)
Any engine work being done. My suggestion is to make sure the engine itself is worthy enough to handle all these mods. Engine block, internals, rings, bearings. How many miles does the engine have?
jaqattack02: (2015-04-02 01:00:42)
Miles aren't that important, just get a leak down test done.
aprophet13: (2015-04-02 02:35:05)
All of the disagreement even in this thread highlights why I am confused. And most people online who post specific setups are making over my power goals so it's hard to extrapolate what would be necessary to make less power.
Don't have the car yet but it has 100,000 mi which compared to my Volvos ~300k seems pretty fresh haha.
Maybe if people could post up their modifications and approximate times like 0-60 and 1/4mi? Looking for around 5 and 13-14s respectively.
amreboot: (2015-04-02 02:43:08)
All of the disagreement?
There are multiple ways to get to your goals.
People have suggested a few good ways to reach that goal.
But ultimately, you need to search more.
We aren't here to spoon feed the perfect answer for you.
There is a reason why we have build threads and a dyno thread.
There should be more than enough information for you to get your answers.
88sinZ: (2015-04-02 03:08:05)
Max total: $1470
[archived image: d52ngs0-2edb48b8-1801-48b5-a134-1f1d442f40d5.png]
Axel kain: (2015-04-02 12:49:35)
as far as retaining the secrecy.... a gutted plenum with the stock top plate - good. turbo, with stock looking intake plumbing and stock MAF (which is capable) -good. keep EGR, run a Cat, and keep idle controls. Nistune averages $400-500, and wouldn't be noticeable without pulling the ECU and popping it open. The upgraded injectors and higher boost will certainly require a tune. if you run a BOV on the intercooler setup, be sure to recirculate it to the intake piping between the turbo and MAF.
G-E: (2015-04-02 19:17:58)
Keep in mind even the intercooler can fail your visual inspection, so it really will depend on stealth and someone to look the other way…
darryl rice: (2015-04-05 03:00:21)
Amen…!!!! Armeboot
irace911: (2015-04-07 01:47:38)
Leak down test? Are you referring to a compression test. If so, compression can fully be at specifications. But the miles of the engine can tell us the mechanical integrity. If you can boost a "z31" at 14psi say, and the engine has 300,000 miles and something doesn't go wrong, you have a godly engine. Funny thing is no one has godly motors. Engine integrity is always a first when rebuilding and it seems you have a good goal. I mean, you can go ahead and and slap on some extra screws to make it faster.
G-E: (2015-04-07 05:12:48)
Compression tests don't tell you how bad the rings and valve seals are, you can have good instantaneous compression but still leak a ton… hence the leakdown test
88Turbozx: (2015-04-12 18:32:42)
My 0-60 is under 5 seconds with a MBC T3 10psi no intercooler, No AC, full CM 3 inch turboback, ASCO gutted plenum with a cover (looks 100% stock to any cops or emissions), and 300lbs of weight reduction. i'm in Cali and my bay looks bone stock. It pulls on E46 M3s, 350Zs, G37s, WRXs, and other "decent" stock cars. This setup would work well for your speed goals and it has a great powerband and response thanks to the plenum.
jaqattack02: (2015-04-13 00:51:28)
Compression tests don't tell you how bad the rings and valve seals are, you can have good instantaneous compression but still leak a ton… hence the leakdown test
This. Leakdown is a much better indicator of overall engine health. Compression is a decent quick test if you don't have access to leakdown gear, or are trying to do it on site before buying.