Jump to content
SAU Community

Recommended Posts

I am in the process of turbo charging my r34 with a DE neo engine and i was going to order forged cp DET Turbo NEO pistons.... my question is, is the DE neo and DET neo head the same? i dont want to make an expensive mistake if the clearances for the valves will touch the top of the pistons because the NA pistons have grooves in them for the valves not to touch and i wasnt sure if it was specifically designed for the DE/NA neo head. Thanks!

Well its because i do not want to run the standard DE naturally aspirated high compression pistons with boost... i have been told that its a "hand grenade" and as such you will have to be between 7-8 psi to stop things from going *boom*. i am just trying to make a reliable build to last me with moderate power, nothing to crazy.

1 hour ago, Dil-Dog said:

i am just trying to make a reliable build to last me with moderate power, nothing to crazy.

With a good ECU and good tuning you are going to make exactly that. Moderate power, nothing too crazy. With the high comp pistons. It's not as if they are HIGH COMP. The compression ratio is still sensible enough for decent boost.

I wouldn't change the pistons for this build.

Yeah i definitely agree with you bro and also... thanks for the reply i really appreciate this community thus far helping a noob out like me. however i feel that it is an investment that is worth it for peace of mind and reliability but really my question is, is it compatible with NEO det pistons? 

23 minutes ago, Dil-Dog said:

Yeah i definitely agree with you bro and also... thanks for the reply i really appreciate this community thus far helping a noob out like me. however i feel that it is an investment that is worth it for peace of mind and reliability but really my question is, is it compatible with NEO det pistons? 

Well, if you're going to go down that path - given that the cam profiles are barely different between turbo and NA, and given that the turbo pistons give more combustion chamber, there should be more clearance. And if there is not, a trial fit up will tell you whether you need to mill a couple of spots on the pistons.

I would bet $500 that there will be no issues.

Yeah they'll fit...
 

You'd be better off getting a turbo motor though, cylinder heads are much better.

Or if you want to cheap out, just run a NA neo on ethanol and run all the boost!

56 minutes ago, zoidbergmerc said:

Yeah they'll fit...
 

You'd be better off getting a turbo motor though, cylinder heads are much better.

Or if you want to cheap out, just run a NA neo on ethanol and run all the boost!

Hey bro, thanks for the confirmation. the real story is... i bought a "neo DET" to replace my NEO de naturally aspirated but i basically got scammed once the engine was delivered to me because it wasnt actually NEO but rather a late series 2 possibly a series 3 that has the plastic hitachi CAS sensor and basically now i am swapping over all the parts. kind of a frankenstien build really. 

Oh, I just realised something.......the Neo DET used RB26 rods. There is therefore a difference in the height from the pin up to the piston crown on the Neo DET pistons compared to other 25s. Not the same as vanilla RB25. I have no specific knowledge of the Neo NA....but I would not expect that they used the 26 rods in it. So, if your plan is to put pistons that you order to suit a Neo turbo onto rods from either the vanilla 25 or Neo NA....I would expect them to not work.

More research required, and potentially you will be better off ordering pistons and rods, or some other piston.

 

4 hours ago, Dil-Dog said:

Hey bro, thanks for the confirmation. the real story is... i bought a "neo DET" to replace my NEO de naturally aspirated but i basically got scammed once the engine was delivered to me because it wasnt actually NEO but rather a late series 2 possibly a series 3 that has the plastic hitachi CAS sensor and basically now i am swapping over all the parts. kind of a frankenstien build really. 

If you have an RB25DET just use that. It will be better than a boosted Neo DE.

@GTSBoy wow bro thanks for that insight, i didnt even think of that! what i will do now is pull the pistons form th de neo and the series 2, take pictures and measurements of them side by side and post them here soon.

@KiwiRS4T i was actually planning to do that after i realized i was scammed how ever the engine's wiring harness and ecu harness will not match the R34's due to the fact that the r34 is only compatible with NEO's

@GTSBoy okay so i been doing research on RB connecting rods and from i have been hearing people say in the forums is that they are the same with the overall height of 121.5mm  AND  from what you can buy online, all the aftermarket brands of connecting rods mention that they are both compatible for 25 and rb26. so that would mean that the difference in Compression and Valve clearance between neo's series 2's and rb26's  must not be from the Rod height but rather the smaller NEO head's dome cc and Pistons. .... what do you think bro?

Edited by Dil-Dog
spelling mistakes and missing words

Oh, the compression difference is wholey and soley because of the different (flatter) combustion chamber shape in the Neo (and therefore different crown shape to keep approx the same compression ratio).

But I may have just painted myself as an idiot. I still actually thought that the rod length was different, not that the 2mm stroke difference was in the pin height in the pistons.

Ive just assembled a grenade so to speak, rb25de neo.

From what i could see,

De neo oil pump has shorter relief valve springs by about 10mm but rest of the pump looks the same as det neo.

De neo rods look to be the same as hydro 25.

De neo pistons have a slightly longer skirt and a little extra volume in the dome but pin height is the same as det neo.

De neo block has no oil squirters, oil feed and return has to be drilled.

De neo cylinder head uses same size valves and lifters as det neo, exhaust ports look to be same size, inlet can be ported out to det size  behind the valves and up the divider however where the intake manifold bolts on will get fairly thin in places and wont match 100% without welding and grinding, but does still fit nice enough for a low buck build.

I used det oil pump springs, gtr rods, arp head studs, supertech valve springs, tomei type b poncams, standard rings measured .014" top .018" second so back in they went.

Probably limit boost to 2 bar and see how she goes

 

On 01.08.2019 at 03:02, Dil-Dog said:

Я нахожусь в процессе турбонаддува моего r34 с двигателем DE neo, и я собирался заказать кованые поршни cp DET Turbo NEO .... мой вопрос, одинаковые ли головки DE neo и DET neo? я не хочу совершать дорогостоящую ошибку, если зазоры для клапанов будут касаться верхней части поршней, потому что поршни NA имеют углубления в них, чтобы клапаны не касались, и я не был уверен, было ли это специально разработано для DE / NA neo голова. Спасибо!

buddy, why are you doing this, from an atmospheric engine to a turbo, if the Japanese have long come up with everything for you and you can immediately put a turbo engine
12 hours ago, NEO25T said:

Ive just assembled a grenade so to speak, rb25de neo.

From what i could see,

De neo oil pump has shorter relief valve springs by about 10mm but rest of the pump looks the same as det neo.

De neo rods look to be the same as hydro 25.

De neo pistons have a slightly longer skirt and a little extra volume in the dome but pin height is the same as det neo.

De neo block has no oil squirters, oil feed and return has to be drilled.

De neo cylinder head uses same size valves and lifters as det neo, exhaust ports look to be same size, inlet can be ported out to det size  behind the valves and up the divider however where the intake manifold bolts on will get fairly thin in places and wont match 100% without welding and grinding, but does still fit nice enough for a low buck build.

I used det oil pump springs, gtr rods, arp head studs, supertech valve springs, tomei type b poncams, standard rings measured .014" top .018" second so back in they went.

Probably limit boost to 2 bar and see how she goes

 

 @NEO25T Hey bro thanks for the reply, its nice to see someone else has gone through the same journey i am doing right now,

so .... what you are saying is that the DE neo pistons are larger/taller than the DET neo pistons and that is what makes up the difference is compression ratios between DET and DE neo's? I am still very keen on using CP forged DET NEO pistons, but before i order i must be 100% certain that i wouldnt run into any valve clearance issues with the DE neo Head. but from what i am hearing and reading, they are the same dome size only the intake ports are smaller and shouldnt have issues hopefully.

Lastly, for your build, what intake plenum did you use? a series 2 r33 det, or r34 det neo, or the DE neo "y" intake that it came with? Thanks alot 

Edited by Dil-Dog

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Place the new daughterboard in the case and mount it using the 3 small black rivets provided, and reconnect the 3 factory ribbon cables to the new board Then, use the 3 piggyback cables from the daughterboard into the factory board on top (there are stand offs in the case to keep them apart. and remember to reconnect the antenna and rear cover fan wires. 1 screw to hold the motherboard in place. Before closing the case, make a hole in the sticker covering a hole in the case and run the cable for the android unit into the plug there. The video forgot this step, so did I, so will you probably. Then redo the 4 screws on back, 2 each top and bottom, 3 each side and put the 2 brackets back on.....all ready to go and not that tricky really.      
    • Onto the android unit. You need to remove the top screen because there is a daughterboard to put inside the case. Each side vent pops out from clips; start at the bottom and carefully remove upwards (use a trim remover tool to avoid breaking anything). Then the lower screen and controls come out, 4 screws, a couple of clips (including 3 flimsy ones at the top) and 3 plugs on the rear. Then the upper screen, 4 screws and a bunch of plugs and she is out. From there, remove the mounting brackets (2 screws each), 4 screws on the rear, 2 screws top and bottom and 3 screws holding in the small plates on each side. When you remove the back cover (tight fit), watch out for the power cable for the fan, I removed it so I could put the back aside. The mainboard is held in by 1 screw in the middle, 1 aerial at the top and 3 ribbon cables. If you've ever done any laptop stuff the ribbon cables are OK to work with, just pop up the retainer and they slide out. If you are not familiar just grab a 12 year old from an iphone factory, they will know how it works The case should now look like this:
    • Switching the console was tricky. First there were 6 screws to remove, and also the little adapter loom and its screws had to come out. Also don't forget to remove the 2 screws holding the central locking receiver. Then there are 4 clips on either side....these were very tight in this case and needed careful persuading with a long flat screw driver....some force required but not enough to break them...this was probably the fiddliest part of the whole job. In my case I needed both the wiring loom and the central locking receiver module to swap across to the new one. That was it for the console, so "assembly is the reverse of disassembly"
    • But first....while I was there, I also swapped across the centre console box for the other style where the AV inputs don't intrude into the (very limited !) space.  Part# was 96926-4GA0A, 284H3-4GA0B, 284H3-4GA0A. (I've already swapped the top 12v socket for a USB bulkhead in this pic, it fit the hole without modification:) Comparison of the 2: Basically to do the console you need to remove the DS and PS side console trim (they slide up and back, held in by clips only) Then remove the back half of the console top trim with the cupholders, pops up, all clips again but be careful at the front as it is pretty flimsy. Then slide the shifter boot down, remove the spring clip, loose it forever somewhere in the car the pull the shift knob off. Remove the tiny plastic piece on DS near "P" and use something thin and long (most screwdrivers won't fit) to push down the interlock and put the shifter down in D for space. There is one screw at the front, then the shifter surround and ashtray lift up. There are 3 or 4 plugs underneath and it is off. Next is the rear cover of the centre console; you need to open the console lid, pop off the trim covering the lid hinge and undo the 2rd screw from the driver's side (the rest all need to come out later so you can do them all now and remove the lid) Then the rear cover unclips (6 clips), start at the top with a trim tool pulling backwards. Once it is off there are 2 screws facing rearwards to remove (need a short phillips for these) and you are done with the rear of the console. There are 4 plugs at the A/V box to unclip Then there are 2 screws at the front of the console, and 2 clips (pull up and back) and the console will come out.
    • So, a bit of a side trip, but one that might be interesting for people with JDM cars and japanese head units. I know @Pac previously posted about a carplay/android auto adapter he installed which used the AUX input, and @V35_Paul put in one of the Tesla style units that replace both screens. The option I went with was a Lsait LLT-YF-VER5.87_2 (https://www.alibaba.com/product-detail/Lsailt-8GB-Android-Multimedia-Interface-for_1601187633672.html). Price was $1,150 for a single unit although they are much cheaper if you are willing to buy 2....$857ea. Make you you get the version 2 not version 1, it is faster and has a better UI - this is the manufacturer listing: http://www.lsailt.com/product/348.html. BTW if you've never bought from Alibaba before, don't be concerned....these guys can't stay in business unless they are responsive, ship fast etc, they were excellent (probably faster shipping than most local places) So, this was my task for a lazy Sat afternoon....looks complex but was all done in a few hours (it probably helps that I had some of it apart before so it was a bit familiar). I also decided to add a HD USB drive recorded at the same time and the unit also supports an aftermarket reverse cam (if you don't want to retain factory) and also AV in and HDMI out It looks much worse than it is, in fact in was genuinely all plug and play (no custom wiring at all). This video was pretty good (skipped a few steps), unfortunately they are an Aussie seller but no longer sell this unit (I guess Carplay/AA adapters are easier to install and much cheaper) https://www.youtube.com/watch?v=T5hJfYOB8Dg
×
×
  • Create New...