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mvp.07

T28bb tuned with bigger cams, issues?

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Need some help! Did a search but couldn't come up with anything related to my specific issue. Probably for good reason :lol:

 

Have been working on a project s14a with the intention of running a stock set up for the time being while focusing on reliability mods, current mods listed below. The car was modified previously but i bought it without complete hot side, ecu, exhaust, fmic and other small bits. Slowly collecting parts and building it in my spare time.

 

Anyway now the dilemma, pulled of the rocker cover to install some rocker arm stoppers and to my surprise found a set of HKS 264 cams. Now originally i thought the engine had stock cams, so i was going to run a T28bb turbo (12psi) with 370cc stock injectors and stock ecu to get me up and running while i saved for more power later on. Future mods planned for the next few months were 550cc injectors, Z32 AFM and Nistune for a reliable responsive set up (aiming 190-200kw).

 

Current Mods:

T28bb turbo (14411-91F00)

S15 injectors

Walbro fuel pump

FMIC

Koyo radiator

3" Exhaust

Stainless intake with pod

RAS

Braided turbo lines

Oil cooler

Baffled sump

Nismo mounts

Major service

 

Question

So now I have to reorganize my priorities with not being able to run the HKS cams on a stock ecu. What are peoples thoughts on running the T28bb with 264 cams, will obviously need injectors (550cc minimum), z32 AFM and Nistune done. If I found 256 cams then it would have be a no brainer and got the setup tuned asap but now I'm abit worried with 264 cams. Don't really want to upgrade turbo either at this stage as i'll be pushing those mods above up the time line, so moneys tight! Thoughts on how it'll run?

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why wouldn't it work? all it has done is shift the power band a little to the right...

 

not to mention when you up the boost on any stock ECU, the timing up top is garbage anyway.

 

it is fine, just run it.. it won't hurt your car.. not to mention the stock ECU ignition map is very aggressive so putting longer duration cams is actually better as it brings down the overall cylinder pressure on the combustion stroke.

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264 cams sounds big, laggy and less than ideal.. maybe you could straight swap them with some baller who wants to upgrade from smaller cams?

 

Ignore me.. an expert has spoken. You could still swap them for what you want I guess

Edited by Junny

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264 cams sounds big, laggy and less than ideal.. maybe you could straight swap them with some baller who wants to upgrade from smaller cams?

 

he's got a small turbo, it won't be that bad

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also S15 injectors are 450cc NOT 370cc.. your car will run like shit on the stock S13 ECU unless you're able to drop the fuel pressure OR just get the Nistune in

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But in pushing the power band further up with the cams, would i not be pushing it to where the t28 is out of its efficiency and out of puff? I.e. my simpleton logic (load of crap?) is maybe sluggish down low with the potential for power up top, but by the time you reach top rev band the turbo is out of efficient anyway so counter productive.. if that makes sense.

 

So i have s15 (440cc) injectors in the rail now (came with car). Before i found the cams i was intending to run a stock setup (ecu, injectors, afm) hence needing to revert to the stock s14 injector which are 370cc due to not having any engine management to support the s15 injectors, limiting that setup to 12psi till i upgraded the other parts. But now things have changed with the cams, i need to go Nistune straight up to cope but just wanted to see thoughts on how it'll run with t28 and that size cams.

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yes that is right, however all the excess exhaust gasses will flow through the gate.. it's fine don't stress too much.

 

They're 450cc not 440cc not 480cc.

 

You don't need a nistune straight up because you have cams and I wouldn't want to run 12psi through 370cc injectors.. AFRs would be lean as and not to mention the stock ignition map is pretty aggressive.

 

 

Just do this:

Install stock injectors

Install stock ECU

 

When you have money:

install 450cc injectors

install nistune

get it tuned

wind it up to 1 bar

 

then:

rip skids and thank me.

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Bit of an update! So i managed to source some parts at some great prices.

 

Have now added 550cc injectors, z32 afm and nistune board ready to be tuned next week.

 

I'm left with turbo choice! I have a T28bb ready to go on but have come across a HKS GT-SS (0.86 rear).

 

Considering i have HKS step 2 264 cams and what looks to be an upgraded valve train, would the GT-SS be more suited or should i grow a pair and have faith with the T28 combination! Btw running a 4.11 ratio 2way.

 

I get the GT-SS with 0.64 would be the responsive solution (equivalent to disco spud 2860 0.64 from what i've read), but how does the 264 s2 cams affect the 0.86 housing?

 

Aim: Responsive 200kw at the wheels, but useable power up to 6000rpm considering i am after a smaller turbo.

 

zoam84.jpg

Edited by mvp.07

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Get a VCt gear back in there

Will drive 10 times better down low with it and a gtss is not much of a upgrade to a t28bb

not worth it unless it was free

Also all the .86 rear housing will do to it is make it 500rpm laggier and shift the power up top and gain maybe 5-10kw

 

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possibly you will be able to run more timing wiht the 86 rear.

 

seriously slap it on and get it tuned up.

 

i reckon it wont be too laggy !!! seriously lag is not that bad on any t2 turbo with 264 cams.

 

i gots a gtx2867, 260/12 cams, its almost too small and f**k anything t28 size lol

haha. slap it together you will be pleasently surprised hey!

 

and most definaltey put a VCT back in there, providing you can get a s15 ecu or what ever is needed to run the vct.

 

if you can slap a s15 ecu in there, you will be able to wire it all up back togehter, and use your s15 injectors etc.

what igniters/pencils you got? s13/14/15?

Edited by n0nac-S15

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^ what power are you getting out of that gtx?? t2 internally gated?

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I've already tried going from a .64 to .86 rear housing on a small t2 turbo on e85

Yes it took more timing and boost not worth it for a daily street car

Went from 250kw on 20psi .64 knock limited more boost detonation to

266kw on 25psi .86

Gained 300rpm lag but on the street really felt different

.64 rear housing was always onto boost with light throttle and felt way better down low and more snappy onto boost

.86 made it come on more progressively and smooth and barely any wheel spin and alil doughy down low

I gained extra 16kw but with 5psi more boost which you would barely feel on the street and was only 4500rpm up

Only notice the extra power at the drags or for dyno comps

 

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no idea havent dynod it yet...

still sorting out boost control.

 

fair enough, what cams pur?

one would think a 264 would make a gtss laggy anyways as its shifting up the powerband anyways.

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Poncams

Yes the larger cams will make it laggier but the .86 rear will make it worse

Just stick with the t28 bb man and keep the money for a new VCt gear

T28 and cams should make 200-210kw

Gtss and cams will make 210-220kw

Edited by pur40m

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I think i'll bolt up the T28 and be done with it for now, it's more effort than anything upgrading again which I was trying to avoid. Would only be upgrading due to turbo and cam size mismatch affecting drive-ability if it does, not for lack of power.

 

The HKS GT-SS produces only a slight bit of power more than the T28 (10-15kw from what i've seen so far) and i'd understand the lack of will to upgrade from a good condition running T28 for little gain. But seeing that my exhaust side is still all apart it's no more effort in my situation.

 

Came across this dyno sheet from a NS member's car which is what got me excited, look at that torque!! I have pretty much the exact same build bar the cams. At 16psi with cams, i'd assume power output coming closer to the 220kw mark like you guys have pointed out but the torque with that peak power seems incredible off that sheet. I'm certain i read somewhere that was with a 0.64 housing, and if it was as simple/cheap as swapping the rear housing for a 0.64 off a busted T28, shit would be crazy!

9zx2f6.jpg

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Would only be upgrading due to turbo and cam size mismatch affecting drive-ability if it does, not for lack of power

 

Well, smaller turbos spool faster than bigger ones, regardless of cam size. Gotta decide on cams and turbo at the same time - If you've decided to keep the cams regardless of turbo then you've only got one variable to play with.

 

That said, isn't the gt-ss similar enough to the T28BB that it's not worth bothering? Plus the usual risks of 2nd hand turbos.

Edited by Skepticism

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I'd love to get the GTX2867R to go with my easy cams

Edited by zefside_s15

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Your right with only one variable to play with being the turbo. The way i see it is is it would cost more to get cams changed then to swap my T28 + a little extra cash to upgrade turbo before i fit it up.

 

I was under the impression the gt-ss was equivalent to a 2860 (disco potato). Still not that big of a difference to the standard turbo. The T28 i have is also bought used (said to be in good condition and has very minimal shaft play), i bought the motor without turbo side thinking it had stock cams at the time till i pulled of the covers. If the gt-ss 0.86 exhaust housing can be swapped for a 0.64 off a t28 simply bolting on, then the larger cams will be able to pack the housing without bottle necking (in comparison to a t28) and still be responsive due to the smaller housing?

 

Car goes in for a tune on Monday so last minute rush on my part.

 

Quick comparison of turbo specs

2qi4f9h.jpg

Edited by mvp.07

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time wise, I think it would be similar, you will get a few hours left out of a day by either replacing a turbo housing or replacing cams.

 

I could the turbo and manifold out of the car in about an hour. swap it over, if you went hard at it, I reckon 4-6 hours max.

 

the cams are pretty easy to do so long as you got a torque wrench. and you got the workshop manual on how to set the timing right before you start anything.

 

if the t28 rear can fit onto the gtss.. that would be the best of all worlds,

get it tuned,

 

and if your still not happy, you may want some poncams or 256/11ish which are better suited to the turbo.

 

a "step 2" or 264/12 cam is more suited to a large t2 or t3 turbo.

 

with the 2867 you wouldn't get the benefits out of it with a poncams, well so I believe. as your going to have inherent "lag" but the engine wont be breating as well.

driveability wise, the procams and the gtx outshine the stocko motor / turbo combo. heaps more driveability and faster acceleration all across the rev range.

over the years people gained significant results from going poncams to procams with the 2871 .64. jusy my 2c.

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A std t28 rear won't fit the gtss

You need a .64 rear from a gt2860rs/gt2871r t2 gt3071r all share the same turbine end 53.8mm exducer

You can get them off eBay from kando dynamic new around $200

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Gt2860/gt2871r have a slightly larger turbine

Which is the same turbine as the gtss

So you would need to get the normal t28 housing machined out

By gcg or Mtq I'm not sure how much they charge but

I know a t25 housing is the same as a t28 as I had a t28 ages ago with a cracked gate flapper and reused my old t25 rear housing

Still made 182kw s13 sr20det non VCt std cams and smic on 15psi

My first turbo setup

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Ended up fitting the T28bb, the 0.86 gtss wasn't what i was looking for and even the with the 0.64, as you guys said there wasn't much of a difference which my tuner confirmed. Will be going in for a tune at the end of the week, will see how the car feels first and think about upgrading the turbo later on.

 

Hoping to get some other help here without making another thread. Sorting out my vacuum lines off the intake manifold and unsure of what goes where and what needs to be capped. (Not running bov if that helps?)

2gso32p.jpg

 

Secondly i found this wire unplugged and don't know where it goes. Traced the wire back and it branches off alternator plug.

2uhwh0n.jpg

 

Thirdly found this plug also unplugged, branches off just underneath fuse box.

dgsdcp.jpg

 

And lastly there are 3 hose that come off the cold side cooler piping. One vacuum nipple, one slightly larger and then a big one. Where do these connect to, intake manifold nipples?

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download the s14 workshop manual to work out what goes where.

 

no.6 is coolant and i think no.1 is too.

 

and a couple of them goto the carbon canister.

 

haha hope that helps a little ;)

 

does your ac fan come on and off? it could be the plug for that? otherwise NFI.

 

download the workshop manual. and have a read u should be able to work out what goes where...

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