Keep My Neo 25t Or Get An R33 25t?

[DRFT 14]

I’m in a bit of a predicament with my NEO RB25DET. I bought an 80000kms neo engine with the plan to drop it into my S14 Silvia (previously fitted with an RB20DET which ran a bearing). The motor is missing its ECU, AFM and wiring loom is cut. I’ve spent the last couple of weeks trying to hunt down those parts to no avail. The only person I found that had an ecu wanted $400 for it. A wiring loom would have been easily over $600. I can’t afford this kind of cash and it’s making me regret going for the later model NEO engine. I’ve been getting laughed at walking into wreckers and asking for NEO parts, they are too rare at this point.

This brings me to my question and the reason I started this thread. Should I make my life easier and re-sell the NEO 25t and just buy a 100% complete 25t from an R33? This will save me a lot of headache and money, but I’m afraid I’ll regret this decision later on if do go along with option B. But is it worth the hassle with the neo motor, in regards to the improvements in the NEO head? Does it really make that much of a difference? I’ve heard that the reason the R34 has 30hp extra over the R33 only because of a boost increase. Does that mean that the neo head does nothing to increase power? I’ve got a 500hp T3/T04e awaiting fitment on the motor (along with many other mods-FMIC, Walbro, manifold etc). Will the neo motor spool the turbo up quicker or will there not be an advantage once the turbo is fitted and the motor is tuned (between the r33 and r34 RB25DET)?

Your thoughts as usual very much appreciated. My heart says keep the Neo motor, my wallet says sell up and get an R33 25t, what do you guys reckon?!

Edited December 21, 2005 by DRFT 14

[madbung]

Talk to an importer and ask for a favour...theres probaly a half cut or 2 floating around with the bits you need or buy off e-bay. Neo.. Neo...Neo!!!

[r33_racer]

go for the option b and get a 33 25. more parts from wreckers available as you know and generally more stuff for sale on here for them also. If your gonna chuck a bigger turbo on it, it will spool up much the same on the neo as it would the plain 25t. The differences your talking about here are bugger all. If it were a 26 or 25/30, 26/30 you comparing it too, then shit yeh we would say u would be insane to sell up. Overall the cheaper it works out to be, the more money you will save in the long run to spend on other things for the car.

[R31Nismoid]

Neo has higher comp, you might not make as much power easily. But it'll be nice.

If your going to put a old slapper/70's technology t0x series turbo on there... i guess go for the cheapest option.

[maximajim]

Neo has 9:1 comp same as r33 rb25.

The Exhaust valves are .5mm larger but the cams have less duration and more lift.

If cost is any concern there is no reason you shouldn't get the r33 motor.

[Abo Bob]

Agree on CR with jim.

I can't believe you can't find a manual ECU cheaper than that. How many people on this website have upgraded to a PFC. They would sell you there old ECU for $100 no worries I reckon. Put up a wanted to buy thread.

That said, the stock ECU wont be able to handle what that turbo will put through it so it will need to be chipped or you need a PFC anyway. Whether you go R33 or R34 you still need a pfc or equivalent.

The NEO head should definitely be a little better than the R33 but you are hamstringing yourself with that old turbo.

It doesn't get the extra power from extra boost. Both are 7psi. It gets it from different head (solid lifters, different cams etc) better ECU and a larger exhaust housing on the turbo.

As for the loom, you either have to make one up or bite the bullet and buy one. Whoever buys your engine should you choose to sell it will probably talk you down based on the fact that you have no loom if they are doing a conversion. I looked at buying a second hand motor when I blew mine recently but the cost v cost of a rebuild makes it not worth while and this is the only situation where a buyer wouldn't need the loom.

[Beer Baron]

i think if you don't have the loom, or the ECU the you have a blessing in disguise. I would do straight for something like a mircotech, or autronic, or wolf or similar. Get a good installer to wire it in (it's not that hard). i think it will work out cheaper in the long run, plus you have a tuneable aftermarket computer straight off the bat.

failing that (try and) sell the neo and buy a garden variety R33 RB25.

[benl1981]

Buy a powerfc - dont waste your time getting a stock ECU - thats going to be your biggest compromise if you do. I think somebody is selling a R34 PFC on the forums.

Buy the loom and youll be away. Failing that just by the R33 motor

[DRFT 14]

I have looked into the aftermarket wire-in ecu idea but was not sure if the these products fully replaced the standard wiring loom or simply spliced into the existing nissan wiring loom. I actually started a thread asking this question but didnt get any useful responses. Maybe you guys may know the answer? My Neo motor actually has all the sensors and wiring on the head intact. Its simply cut from around the alternator wiring side (I got a replacement for that part) and chopped where the thick coil begins to route into the firewall and plug into the ecu. Does this help in relation to wiring up an aftermarket ecu?

I know you guys dont like LINK, but im in NZ and can pick one up (with wiring loom) for $970.

[32vspecII]

didnt you already ask about this before , im sure ive already replied

If you get a WIRE IN aftermarket ECU , like a haltec , motec , autronic , EMS , Microtech or link you will wire it into your motor . You do not use the factory loom (although to save time/money you can adapt the existing loom) . Also all these ecu's use a map sensor so you do not need the AFM

the easiest and best solution is to get a wire in aftermarket ecu

[DRFT 14]

Thank you very much, made my day. And sorry, i didnt see your reply on the thread. $970 will now sort three things out at once- AFM-gone, ecu and wiring sorted.

Il call LINK tomorow morning, if what your saying is correct (im sure it is), then looks like the NEO is staying

[32vspecII]

you forgot the cost of install and tuning though .

make sure you find a tuner who is familar with the ECU and installations into the rb25 . they can be tricky and hourly labor charges can add up . make sure you budget enough $$$ for this .

[Space Goat]

howdy i jus found a r34gtt (neo) computer and other shit on ebay... its only got 23 hours left on it with no bids... offer him a hunj for the computer and he might seperate the stuff... $90 shipped to nz... heres the link anyway... take it or leave it cheers...

http://cgi.ebay.com.au/R34-SKYLINE-COMPUTE...1QQcmdZViewItem

[benl1981]

Go PFC or standard computer - to program a bare bones computer will be costly and never quite as reliable as a factory base tune as PFC or sock ECU has.

[Waldo]

my mate stuck a NEO in his 180sx and he just bought a R33 power fc and that worked fine...so see if you can buy a secondhand r33 power fc.

[32vspecII]

you can adapt a r33 powerfc to the r34 neo

but he doesnt have an engine loom

if he did could get a r34 power fc

aftermarket ecus do take more work to get them handling factory idle/coldstart/aircon control but it can be done and done extremely well . its all down to your tuner and how much money you can throw at him to tune it.

Edited December 22, 2005 by arkon