R33's Trouble In Paradise

[Bjc3000]

Hi everyone, it's been a while since I've been back.

I'm looking for a little insight into my r33 separation pains.

basically the story went like so. i bought the 33, it shit itself. within a month. the crank had been sheared and pistons smashed. kind of long winded. basically. i cried a little.

skip to now. i ordered an imported motor, my skyline is a 1997 s2, so i ordered a series two engine with low k's, good stuff.

or so i thought..

The motor was in fact an rb25det NEO, i really wish i would have known. Anyway i did the swap, there was a few things that needed to be swapped out of the old motor.

oil pressure sender, a/c comp mounting bracket. injectors etc.

all went well, i had to re-pin the CAS as the NEO wiring is a mirror to the S2 CAS.

also the VCT solenoid has a different connector, i re-wired that, but the wiring diagrams i had were quite vague, so atm it's not connected.

the car was able to start and run using the old maps in my E-manage ultimate. i figured as much because it's basically the same engine

i'm to believe that the Neo head has Different cams? and the VCT functions a little differently?

My Cars specs follow

(auto) S2 1997 r33 skyline

600cc injectors (sidefeed)

Hypergear Atr43G3 Sidemount Turbo

Blitz Return Type FMIC

Custom Alloy radiator

Z32 AFM

E-manage Ultimate Piggy back on Stock Ecu with a toshi chip for 18psi (piggyback for auto)

The only thing i couldn't save from the old motor was the Yellow Jacket coils as the mounting brackets between the two heads are different. i'm now running on stock coils that came with the motor. (unsure of the condition)

I've read a Lot on the forums about misfire issues, RB's and Coilpacks, as my car is running... but like shit.

Intermittent misfiring, and misfiring under boost.

i originally had bcpr7's gapped at 0.8 and then i swapped them out to bcpr6's gapped at 0.8 as well

no change in the misfire.

i'm looking at changing the coilpacks out to splitfires, would this be advisable? i've taped the coils and swapped the plugs, the compression test read +/- 6 psi across the board. so good compression. i've put an earth kit on as well and cleaned up all the grounding areas.

i've checked and double checked intake piping, looking for leaks, vac leaks etc.

Can people give me and opinion? i miss my skyline it's been far too long.

also would the r33 ecu be able to handle the vct timing control of the neo head? as in, will it work the same as the rb25det? or will it cause issues.

i just want it running on all 6 properly so i can take it in for a good old fashioned tune.

any opinions?

thanks again.

[GTSBoy]

VCT on both engines is basically the same. It's just switched in and out at certain rpm, and it is just a solenoid with 2 wires that does it. So provided you get the power on the right side it should just work.

The Neo has different cams, yes. Unlike the older engine which has hydraulic lifters, the Neo runs solid lifters like an RB26. The head is also different (smaller combustion chambers, smaller ports). It is a better engine all around. Rated about 20kW more than the older RB25.

The injectors are quite different. How have you got your old sidefeeds installed into the Neo manifold? The coilpacks are probably suspect. Why don't you try sitting the yellowjackets on the plugs without the alloy mounts involved, just for a trial. Yes, I realise the connectors are different, but you have a coil loom to suit don't you? Worst case, find someone who has a set of known good Neo Splitfires and play swappsies.

What boost are you running with that big turbo by the way?

[Bjc3000]

Hey thanks for the fast reply Gts Boy.

Yeah there was a few things that i found a little odd about the injector rail myself, i always thought that the neos had topfeed injectors, but as it turns out, the rail from my rb25det swapped over perfectly, the rail was a little different on the neo, (2 fpr) i just removed the vac line and plugged it.

surprisingly enough, the connectors are the same. the engine itself never actually came with the coil pack loom, i was lucky enough to use my old loom.

i've read places that the very late editions of the r33 came out with a hybrid rb25 det neo, maybe it was some cross over period engine to the 34's. i'll give the yellow jackets a go, i didn't even think of that. cheers. i did get an ecu and loom with the engine, minus the coil pack loom. I looked up against the ecu model numbers, and apparantly it's from a C35 Laurel? damn motor importers.

that was my concern with the VCT. as i'm unsure if i've hooked the wires up right. is there anyway to tell?

Btw, the turbo runs 18 psi when i can get it to spool up. peaked at 21psi once. had to set my boost controller a bit better.

It's had a rich tune since i've had it, but it did pull really hard. Just wanted to get it going strong before it goes in for a tune up

[XRATED]

There is no pos or neg side/pin on the vct solenoid.... its a solenoid/coil, there is no polarity.

I wouldn't go buying spitfires just yet.

Are you running the stock s2 loom and coil packs or have you plugged the original loom onto the neo coil packs? I would buy a set of s2 r33 coil packs (not fking yellow jackets)and sit them on the plugs using the original s2 r33 loom.

Lastly, turn the boost down before you get it tuned... neo engines have more static compression. If you'r running 18psi on a non neo rb25 tune, you may very well be hammering your new engine to death... as well as being the source of your ign issues.

[Bjc3000]

yeah no Problems with the VCT then, thanks for clarifying that up for me.

yeah, i've plugged the s2 loom onto the Neo coil packs. I've got the S2 r33 yellow jackets handy, they went well when i had them on the old engine. any reason why i shouldn't use them bad boys?

i havn't actually been boosting really at all, i knew the compression was different due to Neo Head cc i believe?

i've been babying it so far, as i don't want to drive it due to the miss. it misses sporadically on idle as well. every now and than.

is there a difference between the two looms?

[mark33gtst]

My money is on the coils. You would want to replace the coils before tuning anyway as a preventative measure.

[XRATED]

What did you do about iac?

But first try the previous set of coils or borrow a good set of oem if you know they were good. I don't like yellow/red/green fkn purple copy rip off coil packs. They're prone to more problems than oem coils. My vote is for oem coils or splitfires if you need them.

If s2 oem coils/yello jackets work, just make up an adapter plate to mount them.

[Bjc3000]

yeah thats a good idea with the coils. will give that a go tomorrow.

hope that sorts it out, if not, i've got a worked 25det head, i'll just rip the head off and change it over.

although i've heard good things about the neo's. maybe drop in a thicker head gasket to lower the compression. i think thats what a lot of people do anyway.

[XRATED]

for the love of god don't change the head.... and don't try dropping the compression.

[scotty nm35]

I would say it just needs a tune, the engines will flow vastly different amounts of air at cruise, the afr's will be miles out.

[Bjc3000]

obviously a fan of the Neo heads! i changed pretty much most of the sensors over, i had to change the throttle body and tps. i'm quite certain the IAC was left as is and the connector fitted perfectly. i'll see how it goes with this misfire. it's pretty depressing not being able drive it like it deserves.

[Bjc3000]

Yeah i'd say so, the tune that the car was running was initially very rich, i don't know why.

i would like to remove the misfire before i get it retuned however.

that would be the safest option in my opinion

Edit: unless of course the tune is why it's misfiring

Edited August 28, 2013 by Bjc3000

[Bjc3000]

So i've been around today and picked up some new Spark plugs, Gapped them to 0.8 and did a compression test, compression test looks good, 170-175 across the board,

I noticed however that the only spark plug really fouled was cyl # 2, last time i pulled the plugs Cyl #6 was the culprit. must have changed when i change the coil packs around.

i'm leaning heavily towards them being the issue now, the miss lightened a little but it's still there. less frequent as well.

i did all this in hopes of testing the yellow jackets but as it turns out, they just plain and simply have a different construction and won't fit over the plugs nicely. so i didn't even bother. going to keep going and try to correct this, will post up my findings as i go.

[Bjc3000]

took it for a short run today after changing the plugs out, it runs better up until about the 3-4k mark where it stumbles, i believe it's due for some new coils and a decent tune.

as a side note, at idle, i pulled the coils off one by one, and each one gave a noticeable rpm drop, so my thinking is it's more of an under load deal now, and it free revs to redline no issues. i'll clean up the MAFs and put new coils in and see how that goes, but i'm positive it needs a good tune.

[Ben C34]

Coils always fail first under load. Glad you are on track

[GTSBoy]

3-4k is also where you get boost on full and getting up to peak cylinder pressures. That makes it hard for soft coils.

[Bjc3000]

yeah thats true gtsboy, although i don't think i quite get on full boost till around 5000 / 5500. 3-4 and i'm just going positive, stupid big laggy turbo haha. but cylinder pressure is a given. i'm hoping that squashes a few things.

i've realized that i've got a re-mapped stock ecu, and a mapped aftermarket ecu as well.. i hate my life. The previous owner told me that he got a toshi chip tune to run 18 psi, i just don't understand why it had to be mapped in emanage as well then, if toshi had already tuned it. but i guess i'll find out.

it's been running rich since i've owned it. time to get the AFR's looking respectable i think.

[niZmO_Man]

i did all this in hopes of testing the yellow jackets but as it turns out, they just plain and simply have a different construction and won't fit over the plugs nicely. so i didn't even bother. going to keep going and try to correct this, will post up my findings as i go.

The yellow jackets doesn't fit onto the spark plugs? Did you get the right ones?

[GTSBoy]

Yeah....photos?