Rb25det Neo Tuning Advice

[Toff]

Hi Guys,

First of all i know the questions regarding these motors are all over the site, But none seem to have the information im after at the moment!

Quick run down, Car is being restored at the moment and im not dropping a stock motor back into the car.

My current spec list of the engine is

Holset HX35 Twinscroll 12cm housing

6Boost Top mount twinscroll manifold

Greddy copy inlet/HKS copy Rail

750cc Injectors (Still unsure on what to go for)

3.5" Exhaust

I will be using a Link G4 Or Haltech ECU,Fuel wil be 99RON V-Power.

For my goal of around 500HP ATF, Or possibly 450WHP say, Everyone i have spoke to says keep my immaculate bone stock block and leave it be. Dont open it if i dont have too.

Other reports say the compression is too high (9.1 Isnt high though surely??) And you need a good free flowing setup to minimize back pressure (Again as i have, Apart from say cams??)

One part of me says leave it be, and if i come into knock problems i will rebuild the head, fit cams and ARPs, MLS Gasket.

Compression wise also surely fitting just a thicker gasket will ruin the stock quench pads ability to prevent knock to some extent am i right?

What are peoples opinions on this?

Car wont be dragged, Rarely if ever tracked, Will be purely road use.

R34GeeTeeTees motor is pushing out incredible figures, and still stock block barring head changes yes?

Thanks

Toff

[Ben C34]

Leave it.

Whoever said the compression is to high is silly.

[Toff]

Hahaha thanks Ben just what i thought!

[GTSBoy]

You're talking ~280-300rwkW, which if you look in the dyno thread, for example, you will see is near trivial to hit with nearly stock everything.

[sleptema]

There is a guy running 760hp on the stock bottom end of a neo here in WA. If it is timed/tuned and maintained properly, your 450 will be fine.

I think what they are referring to about "free flowing" is the intake and exhaust. You will need a decent intake pod filter and a hi flow exhaust to make sure it can breathe because I believe the hx35 flow around the same as the gt35.

You will need to upgrade your fuel pump as well.

[Toff]

By near stock everything i mean the block. Everything from intake to exhaust will be new (Ie Greddy plenum, 6Boost mani,3Inch exhaust, Haltech ecu, Upgraded fuel pump, injectors, Intercooler,Custom intake, Etc etc etc)

Only thing left stock is the block.

Sorry for not explaining myself properly, All supporting mods will be there!

And thanks sleptema, 760HP On stock bottom end is insane, Have you got a link to that mate?

On that note also i have found these injectors, http://www.ebay.co.uk/itm/201145001596?_trksid=p2060778.m2763.l2649&ssPageName=STRK%3AMEBIDX%3AIT

What do people think? If i could get a set of say Deatchwerks (600cc) And a matching fuel pump i would rather do that, But these seem ideal if they fit the larger greddy plenum injector locations. Stock NEO Injectors are too short by approx 10mm, So i could mabye shorten the spacers and fit larger washers to compensate for the locators but would rather not...

Thanks

[GTSBoy]

By near stock everything i mean the block.

By "near stock everything" I meant, bottom end, top end, inlet and exhaust manifolds, and damn near the turbo too (as in, a decent Hypergear highflow is able to approach that sort of power!).

As to injectors, any matched set of NEW Bosch 1000cc or bigger injectors, in whatever length and o-ring size you need, will do the job. Stainless ones are the best for E85, but the older ones still go alright. Look up Scotty on here (search for Xspurt injectors) for someone (in Australia, not the UK) that you could buy from fairly easily if you want someone who damned well knows what works.

[XKLABA]

Your in the UK yeah, have you looked at the Syvecs S6, much better ECU then the Haltech and you have the joy of having Ryan G from Syvecs and Paul Blamire of Zen performance as a local tuners who knows that ECU inside out

Also ID1000s with a Walbro 460 as an intank would take care of all your feeling needs

[crashsvg]

umm ....simple 255 intank walbro , 600cc , a decent turbo , 3inch exhaust ,proper clutch and a management of your tuner choice ..no need to touch the moto .... 400-450 easily doable

[XKLABA]

Price up a Walbro 255 and 600cc injectors then price up the Walbro 460 and 1000cc injectors, for whatever extra if any it would be worth it to cover any future mods

Fishing meaddifore comith, my uncle once told me plenty of people catch of little fish on a big rig but very few people catch big fish on little rigs

[Toff]

By "near stock everything" I meant, bottom end, top end, inlet and exhaust manifolds, and damn near the turbo too (as in, a decent Hypergear highflow is able to approach that sort of power!).

As to injectors, any matched set of NEW Bosch 1000cc or bigger injectors, in whatever length and o-ring size you need, will do the job. Stainless ones are the best for E85, but the older ones still go alright. Look up Scotty on here (search for Xspurt injectors) for someone (in Australia, not the UK) that you could buy from fairly easily if you want someone who damned well knows what works.

Sorry mate i didnt really think about what you said haha, Thanks for that mate. 1000ccs will be plenty of headroom, But will i need injectors that big?Surely bigger isnt better in the case of injectors? Am i right in thinking i need adapters again for these?

Your in the UK yeah, have you looked at the Syvecs S6, much better ECU then the Haltech and you have the joy of having Ryan G from Syvecs and Paul Blamire of Zen performance as a local tuners who knows that ECU inside out

Also ID1000s with a Walbro 460 as an intank would take care of all your feeling needs

I am in the UK yes, And i considered Syvecs briefly but dismissed it too quickly, Just checked there website and they can build plug and play harnesses, which may be worth looking at over the Haltech/Link options!

And thats good then, was on the lookout for an intank that would flow enough.

umm ....simple 255 intank walbro , 600cc , a decent turbo , 3inch exhaust ,proper clutch and a management of your tuner choice ..no need to touch the moto .... 400-450 easily doable

Would a 255 not be pushing it though to get that sort of power?

Just what i wanted to hear on the engine part!

Price up a Walbro 255 and 600cc injectors then price up the Walbro 460 and 1000cc injectors, for whatever extra if any it would be worth it to cover any future mods

Fishing meaddifore comith, my uncle once told me plenty of people catch of little fish on a big rig but very few people catch big fish on little rigs

Hahaha thankyou mate, As commented above surely i would be pushing a 255. 1000cc injectors may be the way to go then!

[Toff]

Little thread bump,

Just on with ordering bits up for the motor (Delayed i know) And currently have:

• Both intake and exhaust gaskets
• Timing belt kit
• Exhaust manifold studs & Nuts
• Spark plugs
• 850cc Bosch injectors http://www.ebay.co.uk/itm/181687481776?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
• Greddy intake
• Hybrid performance twinscroll manifold
• 3.5" Turboback
• Holset HX35 Twinscroll 12CM Housing (Compressor racing spec turbo not a standard truck unit)
• Syveces S6 Ecu
• R33 Gtr Intercooler
• 4" Intake
• Splitfire coilpacks
• NGK iridiums (Heatrange 7?)

Thats were im thinking at the moment, Going for the UNOPENED Engine option as its a mint engine currently so no point in splitting it right? If the headgasket goes at a later date (Should it though if tune is correct?) I will have to put one in.

Goal for power is 550Hp At the Fly, so roughly 470Hp ATW, Or 360RWKW thereabouts.

Thanks

Toff

[xxxxx]

Don't think all of that's needed for Your goals. Also would have opted for a different turbo but that's just me.

All the best with your build, hope you net your goals.

[Blackkers]

Headgasket will be fine at that power level considering boost should be low 20's psi. If you're worried fit ARP head studs. You can do that one by one with the head in place too to save many headaches

[AngryRB]

yeah I would personally not get fancy with manifolds and special "race spec turbos", Twin scroll and a GT35ish turbo sounds overkill and if not done right you could end with a dog of a thing when a simple stock manifold and hypergear will guarantee you results. The 3076 is king in your power range, Look up Mafia's thread, the sound is awesome.

Are you using 2 wastegates?

Edited March 17, 2015 by AngryRB

[Toff]

Thanks for the responses guys.

turbo and manifold I already have, Turbo was cheap at £450 new and there supposed to hit 600hp max so just a tad over my goals.

Need to dig a few dyno graphs/posts out of the turbo, supposed to be very responsive with the spec But we will see.

Will be using 1 large gate as it merges into one at the bottom, turbosmart 50mm perhaps.

what else would you change on it? 100% leaving intermale stock for now.

On the manifold point as well I thought stock was shockingly restrictive at 350rwkw onwards? Hence people killing motor's and hypergear cutting that one up and making a custom one? Twin scroll should bring the boost threshold down too.

For future reference I will put up graphs once the car is finished.

Thanks!

[STATUS]

420rwkw (564rwhp)

Std NEO, std manifold externally gated, hyper gear turbo @27psi.

Run 420rwkw on Springy motors dyno and on my dynapack.

Credit to their work, welding is awesome (HAVOC fabrication)

id1000cc (increased base pressure)

dual walbro 400 pumps

std cams and springs

Hypergear ATR45SAT

splitfires would not hold up but D514a work fine at 0.8mm

Haltech plat Pro with wideband and flex sensor.

E85

[GTSBoy]

Has that got GTR throttles on it Trent?

[STATUS]

Has that got GTR throttles on it Trent?

Yeah GTR TB and plenum.

Just like a rb26 only better.

[Toff]

Holy shit that's incredible! Manifold completely stock? Do the ATR45 turbos sit in stock location with no spacer etc? Blew my theory of the stock manifold being restrictive out the water lol.