Doing a +t conversion on an unopened RB25DE NEO (R34 GT)

[hey_aleks]

Doing a +t conversion on an unopened RB25DE NEO (R34 GT)

Just before I list everything that I have done so far (not finished yet), I'd like to say that I've only been doing my own work on cars for the past 3 months and am not very technically knowledgeable on the field. I have however been given a vast amount of advice from real tuners and mechanics who actually do the conversions. If i have done something incorrectly please tell me so that I can change it.

These are the parts that I had to use:

Parts (R33 GTS-T IMPUL used as a donor car):

• R33/R34 turbo manifold gaskets ($55)
• R33 RB25DET turbo manifold
• R33 RB25DET elbow compressor
• R33 RB25DET S1 turbo with
• R33 RB25DET dump pipe
• 30CM extension to make the dump pipe meet with the cat which can be substituted by having a long decat pipe created by any exhaust place if you want a louder system(Instead of this, I just used the entire exhaust system from my 33 IMPUL sedan)
• R34 GTT injectors on an R34 rail
• R34 RB25DE NEO intake manifold (Re-used manifold gasket)
• 255LP Walbro fuel pump (Why not use this chance to start fresh and upgrade a cheap part)
• Fuel filter replaced
• R33 RB25DET S1 AFM (had to re-wire this which is easily done as you just have to merge two ground wires)
• R34 GTT AUTO ECU (You CANNOT use a NON-R34 ECU on an R34 as the LOOM has a different ECU plug. Some people on the internet will just tell you to use an R33 ECU like they did tome which is completely wrong so be careful. Also if you have an AUTO you wont be able to piggy back off of the N/A ECU so you will have to purchase an AUTO TURBO ecu and hopefully put a nistune on it. The person who sold me the nistune pulled some ignition timing off to compensate for the high comp engine in order to safely get the car to a tuner or be drivable. If you do use a manual ECU your auto system will be f**ked. If you use a standalone ECU your auto system will be f**ked. All of this information was given to me by the person who programs the nistune units and a few tuners have also advised me of these issues)
• Currently I do not have a BOV being used. The R34 N/A intake manifold is much longer then the turbo ones which does not allow me to use an R33 cross-over pipe. I do have theR34 and R33 turbo manifolds in my garage but want to see if the y-intake will work without a BOV. If there are issues, I will install an aftermarket BOV somewhere along the piping.
• R33 RB25DET S1 Inter cooler (I am using all of the stock inter cooler piping for now except for fabricating another piece of pipe in order to compensate for the short cross-over pipe)
• R33 RB25DET S1 O2 sensor (I had to also re-wire this as it was attached to the dump pipe before installed. If you can take it off and put the R34 one on that would be the best option but this was not possible for me as I had already put everything back together and I don't want to break my hands taking it off)

OIL FEED:

• What I did for this line was tee into the stock oil sensor right next to the standard oil filter location. A brass "T" piece placed between OIL sensor (right next to oil filter) which runs a braided hose line via the T piece to the top of the turbo.

OIL RETURN:

• The NEO block does not have the standard return plug so around 30CM to the left of where the standard oil return plug should be, there is a hole blocked by a plug (similar to sump plug). What I have done is run a high pressure and heat resistant 300PSI hose from a replacement bolt which attaches to the hose and is clamped down, the stock metal piece (also clamped). I did have to use an angle grinder to shorten the piece which fits under the turbo in order to avoid too many bent lines.

WATER FEED + RETURN:

• Both of these lines were used in conjunction with the heater hoses which are near the firewall above the O2 sensor (The hoses are a decent size and will most likely be covered by a silver heat protector). I put a plastic heat resistant "T" piece in between where I cut both hoses and am running two corner pieces which bolt on to the sides of the turbo.

My shitty tips:

• Be ready to improvise
• Every conversion has been different and don't be afraid to get creative
• If you are doing the conversion and expect to be done in a few days please don't do it. Expect the worst (unless you are knowledgeable on engines and/or have done this before)                
• I went into the conversion assuming my car to be not drivable for a few weeks so I put it in the garage with decent lighting
• Take your bonnet and front bar off as soon as you start
• Try and keep the car in a garage with good lighting as this helps SO MUCH YOU DON'T UNDERSTAND I WAS USING MY PHONE'S FLASHLIGHT FOR THE FIRST FEW DAYS f**k THAT SHIT
• Be prepared to get around 50 cuts per hand and literally shed blood, sweat and tears (if it doesn't start)
• Keep track of every bolt, nut, screw, hose, nipple, ground (EXTREMELY IMPORTANT) and have the work shop manual printed if you can which is extremely helpful
• The intake and turbo manifold bolts are recommended to be torqued to spec (which I did but they still felt quite loose to me so I decided to tighten them further. You shouldn't get snapping studs unless you tighten/loosen at an angle due to R34s being a bit younger but be prepared for this to happen as it is common and fixable)
• The reason for the conversion is to get some hands-on experience with an engine. I did have an RB25DET I could have engine swapped but where's the fun in that. Also the higher comp engines apparently hit boost extremely early on in the RPM range which I wanted to experience for myself
• The whole process would be 150X easier with the engine out of the car (not that hard of a process)
• For the turbo lines, take your hard lines and possibly the turbo to a specialized auto shop. For example, I took mine to Adelaide's OG speed shop and they were able to sort out some lines for me. They were not right the first time around (due to a misunderstanding on my end) so I did have to improvise with the water lines as straight bolts do not fit on the sides of the turbo and corner bolt on pieces are much easier. It's hard to explain the whole turbo line setup so the auto shops will be able to help. In my opinion the turbo lines are the only "hard" part of the conversion and getting the right configuration for these lines was definitely the hardest step for me.

Edited September 14, 2016 by hey_aleks

[hugh jaynous]

Sweet, I was looking into doing this myself as I've heard and read lots if good things about +T conversions. Any pictures going up? Also how long was your car in the garage for? Sorry for asking so many questions as I'm located in North America and parts are definitely not easy to come by plus taking time off work, thanks in advance man!

[Binarydata]

Thanks for doing this write up. I always find it good to read a few people experiences before doing something like this. (even though it will still be in a couple of years) 

 

 

Thanks!

[hey_aleks]

Yeah I wish someone had done one for an R34 when I began my conversion  ... I work full time so the car was in the garage for 2 weeks (only worked on heavily on weekends and spent the week days getting parts). The reason why it took so long is because there aren't many exact guides or tutorials on the conversion and nothing is engine specific. It's kind of a blank area and I find it really hard following written guides without any pictures. Of course now I know the layout of my engine bay and most of its components. What I used to get a better understanding was the workshop manual for the NEO DE and DET 

I was told a lot of wrong info which caused extreme delays. A hug amount of turbo conversions are done on standard RB25DEs not NEOs and the blocks are indeed different.

Two examples of being told incorrect information:

• I rang two tuners who apparently "specialize" in skylines and have done many +t tunes. Both told me that I was able to use the 33 auto turbo ecu to safely drive the car to their located and then they would install a nistune piggyback on my stock ECU for the tune. Once I corrected them after trying to fit it, they told me the standard 34 auto non-turbo ecu would be fine to drive it there and that they would proceed with installing the nistune piggyback once I had arrived. The night before my tune (I had to take the car there at 8:30AM), the tuner I chose to go with rang me up and said I had to get an R34 auto turbo ecu before the tune or it wouldn't be possible. Fortunately, he happily offered to sell me a $350 bone stock auto turbo ECU to proceed with the tune (still had to pay for the nistune and tune itself). Quickly told him to f**k off and have now chosen a tuner who was recommended by a mate. 
• I was talking to two mechanics who deal with skylines all the time. One mechanic told me to ignore the water lines for the turbo as they aren't needed and he always sees skylines without them on stock and aftermarket turbos. This was my original plan as it made things so much easier. I then talked to a few other people who have a vast amount of experience with skylines and they quickly told me that ignoring the water lines was the stupidest decision and that the turbo would quickly seize.

If I was to do it all again, I think I could do everything over a single weekend. Like I said the hardest part was setting up the turbo lines. I recommend making a plan before you start dismantling the engine and making sure that whatever engine you're turbo converting is the same as the guide you are following. Please guys if you have absolutely any doubts or want pics or need me to clarify anything, don't hesitate to text me on 0421 802 474 anytime....... When I started the conversion I hated bothering people with questions but I am not at all bothered to help anyone out and to help people learn from my mistakes. 

[hugh jaynous]

Thanks for some more incite into the conversion, I understand that your tuners have said only the gtt ecu chipped would work but doesn't a greedy emanage piggy back also work? I've seen 3 other members at least have it straight piggy backed from the Na gt ecu and they are running 200~rwkw.

[hey_aleks]

The standard GT N/A can be chipped but if it's auto it will cause issues (according to them). Since the module which controls the auto system is in the ecu itself (unlike the 33s where it's separate from the standard ECU), it will cause the system to play up. That's why you can't use some standalone ECUs because they don't have the auto system. Now this is going off of what the tuners and the person who programs Nistune have said so it might not be 100% right mate.

[DatsunBanana]

Great write up. Have you got a pic of the dump pipe extension? Not sure the tuners advice is quite right about the ECUs though ... page AT-3 in the R34 service manual says "Vehicle with RB20DE and RB25DET engine has TCM integrated into ECM. Vehicle with RB25DE engine has TCM and ECM separately." I wonder if they were getting mixed up with the RB20? Or maybe they meant that using the DET auto ECU can cause problems which would tie in with what I've been told - that a manual DET ecu is a better choice on an auto DE+t as the separate trans controller will just continue to do it's thing. That made sense to me.

[hey_aleks]

Oh well it's good that you clarified that mate! Unfortunately I already spent quite a bit on another ecu and the piggy back . They didn't exactly say what the problems would be if they did piggy back it so I'm not entirely sure, maybe they are right.

I'll update the info in the post though so if anyone else is doing the conversion, they don't change their ECU. Cheers mate!

As for the dump pipe extension, I ended up just using the entire exhaust I had lying around from an R33 sedan which ended up fitting perfectly. For the extension, just go ahead and measure the distance from the dump to the catalytic converter. Then all you have to do is bring the cat or dump to an exhaust shop, tell them you need to extend it as it's a bit short due to being an R33 part and they can get that done quite easily. I nearly did this but realized that I'd be able to use my 33 exhaust.

 

[hey_aleks]

On 9/14/2016 at 10:44 AM, hey_aleks said:

Doing a +t conversion on an unopened RB25DE NEO (R34 GT)

Just before I list everything that I have done so far (not finished yet), I'd like to say that I've only been doing my own work on cars for the past 3 months and am not very technically knowledgeable on the field. I have however been given a vast amount of advice from real tuners and mechanics who actually do the conversions. If i have done something incorrectly please tell me so that I can change it.

These are the parts that I had to use:

Parts (R33 GTS-T IMPUL used as a donor car):

• R33/R34 turbo manifold gaskets ($55)
• R33 RB25DET turbo manifold
• R33 RB25DET elbow compressor
• R33 RB25DET S1 turbo with
• R33 RB25DET dump pipe
• 30CM extension to make the dump pipe meet with the cat which can be substituted by having a long decat pipe created by any exhaust place if you want a louder system(Instead of this, I just used the entire exhaust system from my 33 IMPUL sedan)
• R34 GTT injectors on an R34 rail
• R34 RB25DE NEO intake manifold (Re-used manifold gasket)
• 255LP Walbro fuel pump (Why not use this chance to start fresh and upgrade a cheap part)
• Fuel filter replaced
• R33 RB25DET S1 AFM (had to re-wire this which is easily done as you just have to merge two ground wires)
• R34 GTT AUTO ECU (You CANNOT use a NON-R34 ECU on an R34 as the LOOM has a different ECU plug. Some people on the internet will just tell you to use an R33 ECU like they did tome which is completely wrong so be careful. Also if you have an AUTO you wont be able to piggy back off of the N/A ECU so you will have to purchase an AUTO TURBO ecu and hopefully put a nistune on it. The person who sold me the nistune pulled some ignition timing off to compensate for the high comp engine in order to safely get the car to a tuner or be drivable. If you do use a manual ECU your auto system will be f**ked. If you use a standalone ECU your auto system will be f**ked. All of this information was given to me by the person who programs the nistune units and a few tuners have also advised me of these issues)
• Currently I do not have a BOV being used. The R34 N/A intake manifold is much longer then the turbo ones which does not allow me to use an R33 cross-over pipe. I do have theR34 and R33 turbo manifolds in my garage but want to see if the y-intake will work without a BOV. If there are issues, I will install an aftermarket BOV somewhere along the piping.
• R33 RB25DET S1 Inter cooler (I am using all of the stock inter cooler piping for now except for fabricating another piece of pipe in order to compensate for the short cross-over pipe)
• R33 RB25DET S1 O2 sensor (I had to also re-wire this as it was attached to the dump pipe before installed. If you can take it off and put the R34 one on that would be the best option but this was not possible for me as I had already put everything back together and I don't want to break my hands taking it off)

OIL FEED:

• What I did for this line was tee into the stock oil sensor right next to the standard oil filter location. A brass "T" piece placed between OIL sensor (right next to oil filter) which runs a braided hose line via the T piece to the top of the turbo.

OIL RETURN:

• The NEO block does not have the standard return plug so around 30CM to the left of where the standard oil return plug should be, there is a hole blocked by a plug (similar to sump plug). What I have done is run a high pressure and heat resistant 300PSI hose from a replacement bolt which attaches to the hose and is clamped down, the stock metal piece (also clamped). I did have to use an angle grinder to shorten the piece which fits under the turbo in order to avoid too many bent lines.

WATER FEED + RETURN:

• Both of these lines were used in conjunction with the heater hoses which are near the firewall above the O2 sensor (The hoses are a decent size and will most likely be covered by a silver heat protector). I put a plastic heat resistant "T" piece in between where I cut both hoses and am running two corner pieces which bolt on to the sides of the turbo.

My shitty tips:

• Be ready to improvise
• Every conversion has been different and don't be afraid to get creative
• If you are doing the conversion and expect to be done in a few days please don't do it. Expect the worst (unless you are knowledgeable on engines and/or have done this before)                
• I went into the conversion assuming my car to be not drivable for a few weeks so I put it in the garage with decent lighting
• Take your bonnet and front bar off as soon as you start
• Try and keep the car in a garage with good lighting as this helps SO MUCH YOU DON'T UNDERSTAND I WAS USING MY PHONE'S FLASHLIGHT FOR THE FIRST FEW DAYS f**k THAT SHIT
• Be prepared to get around 50 cuts per hand and literally shed blood, sweat and tears (if it doesn't start)
• Keep track of every bolt, nut, screw, hose, nipple, ground (EXTREMELY IMPORTANT) and have the work shop manual printed if you can which is extremely helpful
• The intake and turbo manifold bolts are recommended to be torqued to spec (which I did but they still felt quite loose to me so I decided to tighten them further. You shouldn't get snapping studs unless you tighten/loosen at an angle due to R34s being a bit younger but be prepared for this to happen as it is common and fixable)
• The reason for the conversion is to get some hands-on experience with an engine. I did have an RB25DET I could have engine swapped but where's the fun in that. Also the higher comp engines apparently hit boost extremely early on in the RPM range which I wanted to experience for myself
• The whole process would be 150X easier with the engine out of the car (not that hard of a process)
• For the turbo lines, take your hard lines and possibly the turbo to a specialized auto shop. For example, I took mine to Adelaide's OG speed shop and they were able to sort out some lines for me. They were not right the first time around (due to a misunderstanding on my end) so I did have to improvise with the water lines as straight bolts do not fit on the sides of the turbo and corner bolt on pieces are much easier. It's hard to explain the whole turbo line setup so the auto shops will be able to help. In my opinion the turbo lines are the only "hard" part of the conversion and getting the right configuration for these lines was definitely the hardest step for me.

 

[hey_aleks]

2 minutes ago, hey_aleks said:

 

 

[DatsunBanana]

The photos are very helpful. Just wondered when you tighten in the t-piece for the oil feed, is it just by chance that the take off is pointing in the right direction? Also it looks like a male end facing toward the camera but I thought it should be female to connect the sender to?

[hey_aleks]

Basically I tightened it without the small black piece connected to it. After it was reasonably tight (Don't do it too tight, maybe around what the manifold bolts are tightened to?), I rotated it once until it was facing the direction I wanted it to. When you do run the car for the first time just let it idle and check every line you have changed for any leaks at all which need to be addressed before you attempt to drive the car. I also recommend getting a consult cable to see if there are any faults. 

For the oil return be extremely careful. On the NEOs, you have to use the plug which is left of the standard DET return plug. Oil goes back to the pan with the help of gravity, and only gravity. This means that it should be as vertical as possible or you WILL end up leaking oil when the line starts getting blocked (which happened to me). This line is completely different to the oil feed as it pumps it to the top of the turbo without the help of gravity. I'll send you a picture tonight of the oil return I am going to try and use.

[DatsunBanana]

Thanks, I already took a punt and bought the fitting I think I need for the oil return so it will be interesting to see a photo of what you've got. I measured the plug you're talking about as best I could without undoing it from the block. It's about 1 inch diameter so I reckon it's a 3/4 BSPT thread (same as Japanese JIS) from the info here https://en.wikipedia.org/wiki/British_Standard_Pipe

I bought a straight hose tail adapter with a 5/8" outlet to fit a 16mm internal diameter hose like this http://www.ebay.co.uk/itm/Brass-Male-bspt-Hose-tails-Hosetail-Fitting-Con-1-8-to-2-Water-Gas-Oil-Fuel-/111269900680

I've bought a T3 drain flange also for 16mm ID hose like this http://www.ebay.co.uk/itm/Turbocharger-Oil-Drain-Return-Flange-T3-T34-T35-T04-Garrett-Turbo-RS-Cosworth-/391484877901

 

[hey_aleks]

Hey mate sorry for the late reply, been quite busy. In the pic of that hose tail adapter, the nipple looks extremely small for the oil return. Just make sure it's the same width as the straight hose tail adapter since it needs to flow freely to the pan via gravity. Also when you start it for the first time basically just let it idle and watch for absolutely any oil leaks from the adapter, return hose and the oil pressure sensor we are tee'ing into. I did have some issues yesterday with my stuff leaking by I've tightened it all up and will have a look tonight after work to make sure it is all flowing correctly.

[DatsunBanana]

Yeah, you're right about that pic. It must be a generic pic of a smaller adapter. The one that I actually ordered has the same size tail as the drain flange in my other pic. Both have outer diameter of 16mm to fit inside the hose. The narrow point will be at the turbo flange which has an 11mm bore. The hose tail at the block has a similar bore but maybe a fraction bigger. Hope it'll be enough but I'll check it all like you say and keep the hose as vertical as possible.

[hey_aleks]

OH I thought it was exactly what you were buying haha

Keep posting when you start putting stuff together or ordering parts so people can have a look at what we've done when they try turbo their 34.

My oil drain seems to be running nicely now, no dripping but there is still oil in the turbo compressor at times but there is absolutely no shaft play.

Let me know what your plans are

[hey_aleks]

[DatsunBanana]

Looking good. I see you did use the 33 inlet in the end. Was that so you could get the BOV in easily?

So here's pics of adaptors I've bought and my theory behind it is this ...

I saw on a few non-Skyline +turbo threads that people use the block coolant drain plug for turbo water feed. E.g. I read about that for a Nissan Patrol. Also from what I've read, this seems to be 1/4" BSPT (tapered) thread on the RB25. It's also just a couple of inches below the place where the DET water feed would be so as the photo shows I've bought an adaptor to use the standard water line (with a bit of careful bending to reach the lower position). Photo shows: 1/4" BSPT to BSPP adaptor. A 1/4" BSPP banjo bolt which is a close but not perfect fit in the 14mm standard water line banjo (I think the copper washers will form the seal OK) and the block coolant drain tapping I hope to use. Just keep in mind that this is theoretical until I actually try it and report back.

For the oil drain I've got the two adaptors shown in the pic. One is easy - an off the shelf T3 flange. The other is just a hose tail which I hope is the right thread. I believe the block tapping for the VCT oil drain (same one you're using) is 3/4" BSPT. Again - I won't know until I try it unless anyone can confirm.

I've still got quite a few parts to get and on a tight budget so might be a while till I can confirm any of this.

[hey_aleks]

Nice pics mate good thing that you're planning things before putting them in unlike many others! The more stock hard lines that you can use the better the setup will be I reckon...

In regards to the coolant return, make sure you check that once the coolant drain plug is removed, it actually isn't blocked off at the end. When I took mine off, I put a zip tie through and the tip became blocked off by something inside. I didn't really think to check if it maybe it drains vertically and there may be a hole below where the wall cuts off. Do some checks if ya can mate because if it does have a vertical drain hole, I'd be keen on doing mine the same way as yours!

By the way I rang a few mobile bolt removers yesterday. If the drain plug for the oil in the turbo ends up causing issues, another option for us is to have the oil pan taken out. Once this is done, we need to also replace the oil pan gasket and do an oil change basically. Once it's taken off, we take the pan to someone who could tap and trill it for an oil return line which would work nicely in my opinion because the line would be quite vertical and run directly down to the pan.

Another option would be to purchase a scavenge ($100 ish?) and have the feed be pumped through it back into the return plug which would reduce the chance of a blocked line due to insufficient downward gravity. However according to a few people, these pumps do tend to fail due to excessively heated oil so constant monitoring would be needed.

Yeah I've decided to try and get the 33 crossover pipe just to see if there are any power gains/losses with the BOV connected and working. I do know that not having a BOV WILL NOT CAUSE ANY DAMAGE TO THE TURBO unlike what many people say on the internet so if you still want to go ahead with that it will be fine. You'll need to possibly craft up a custom intake pipe without the BOV lines if you're planning on not running one though.

Keep me updated man looking good so far!

[DatsunBanana]

Any progress on yours? I might end up doing this a bit sooner than I thought as I just got a package deal on GTT ECU, downpipe, injectors and a nice big FMIC with pipes. Didn't really intend to spend the money on all that stuff so soon but for some hard to get items at a fair price I had to say yes :-)