Help Regarding Turbo Choice + Few Rb25 Questions

[sweefu]

Hello everyone,

I am putting an RB25DET engine and gearbox into my R31 Skyline. I am picking up the engine/gearbox next month, at the moment it is still in a wrecked S2 R33. My car is used mainly for drifting but also the occasional regular track day. I will probably start entering a local hillclimb next year too.

I have a few questions, first of all I'll list the gear which I already know is on the motor:

S2 RB25DET 100 000km

Sard 700cc injectors (have yellow caps?)

Z32 AFM

Apexi Power FC + Hand controller

Sard adjustable FPR

Possibly 'stage 1 cams' but not sure about this. The car was running a GCG turbo (unsure on specifications), but the owner is keeping the turbo. So now I need to decide what sort of turbo to buy for it, given the supporting mods I already have.

My understanding is that no matter what, I will have to have the ECU re-tuned, unless I get the exact exact same turbo again? A GCG turbo is out of my budget, so looks like the ECU will need to be retuned.

I've been reading old threads and the RB25 dyno results thread, it seems that the Kinugawa TD06-20G seems to be quite popular? I am having trouble finding it with the 10cm housing though, I think 12cm would be too big. I am not looking for big power, I would like the car to be responsive. Can anyone suggest some good turbos to look at? My budget is $800 - $1200 roughly, I would prefer it to fit on the stock manifold and have an internal wastegate so I can keep the engine / engine bay looking as stock as possible.

Secondly, it looks like the timing belt and water pump are new, I assume they have been done at 100 000km. Should I change these again just to be sure? Or maybe just the timing belt? I'd like to do as much preventative maintenance as I can before putting the engine into my car.

I will need to buy a boost controller also, so the car will have an electronic boost controller.

Is there anything else I should be looking at?

Any recommendations or advice about the engine and choice of turbo would be greatly appreciated.

Cheers,

Anthony.

[75coupe]

for your budget and needs, hypergear turbo, stock lines, stock exhaust position, internal gate

[sweefu]

for your budget and needs, hypergear turbo, stock lines, stock exhaust position, internal gate

Thanks for the advice. The ATR43? What size housings would you suggest?

Thanks.

[petero'nell]

Get a stock turbo high flowed from hypergear, they about same response as stock and makes around the 240rwkws mark. Or get their ATR43 ss1pu for responsive 260rwkws mark as I'm using one my self at moment.

It appears to be a .86 turbine with a billet compressor in .60 compressor, internally gated, factory bolton. They run fnt turbine nozzles so their response don't necessary follow the A/R size. My dyno sheet is in the dyno result section

[ARTZ]

Thanks for the advice. The ATR43? What size housings would you suggest?

Thanks.

just message Hypergear and tell him what you want...he always replies fairly quickly and will know what is best for you..

he also has the tdo6 turbos in 10cm but no internal gate so its a bit of effort to get it on a stock manifold...better with a high mount...kick ass little turbo though..

[sweefu]

Get a stock turbo high flowed from hypergear, they about same response as stock and makes around the 240rwkws mark. Or get their ATR43 ss1pu for responsive 260rwkws mark as I'm using one my self at moment.

It appears to be a .86 turbine with a billet compressor in .60 compressor, internally gated, factory bolton. They run fnt turbine nozzles so their response don't necessary follow the A/R size. My dyno sheet is in the dyno result section

Thanks for the help, I will look for your dyno sheet.

I would like to have the possibility of more power later on, so should look for a turbo capable of supplying ~260rwkw or so later on. I plan to use a 3-stage boost controller, so was hoping to have actuator pressure (~12psi) then 16psi and 20psi, or 15psi and 18psi etc, whatever the turbo would be suited for. From what I understand the injectors, AFM and ECU are all fine for big power, the stock manifold and stock crossover pipe will restrict a bit anything past 260-280kw?

So if the turbo was capable of 260 - 280kw that would be great, for later on.

[sweefu]

just message Hypergear and tell him what you want...he always replies fairly quickly and will know what is best for you..

he also has the tdo6 turbos in 10cm but no internal gate so its a bit of effort to get it on a stock manifold...better with a high mount...kick ass little turbo though..

Thanks mate. I emailed Hypergear and Stato replied within 5 minutes - 10.45pm! What a service. He is going to give me a call tomorrow to chat about my options. Sounds like a Hypergear of some description would suit my needs well though. I know I am restricting myself by wanting to stick with stock manifold, but it's once less thing to worry about for police attention/my budget. It's easiest all round if a turbo would just bolt on.

Hopefully there will be an option which will be capable of response with low 200kw and still support 260+kw

[R31Nismoid]

My understanding is that no matter what, I will have to have the ECU re-tuned, unless I get the exact exact same turbo again? A GCG turbo is out of my budget, so looks like the ECU will need to be retuned.

I've been reading old threads and the RB25 dyno results thread, it seems that the Kinugawa TD06-20G seems to be quite popular? I am having trouble finding it with the 10cm housing though, I think 12cm would be too big. I am not looking for big power, I would like the car to be responsive. Can anyone suggest some good turbos to look at? My budget is $800 - $1200 roughly

Well a tune is roughly going to cost you $600-$800, so factor that in and add on $1000/$1200 for the new turbo...

You're then sitting on around $1800/$2000... which is pretty much GCG Hi-flow money right there mate - No tune, bolt on and off ya go totally stock looking.

Would seem the logical choice given your budget.

[sweefu]

Well a tune is roughly going to cost you $600-$800, so factor that in and add on $1000/$1200 for the new turbo...

You're then sitting on around $1800/$2000... which is pretty much GCG Hi-flow money right there mate - No tune, bolt on and off ya go totally stock looking.

Would seem the logical choice given your budget.

Quite a good point! I didn't look at it that way. I will contact the guy I am buying the engine from and see about the details of the turbo. The other problem is I can't find out what boost he was running - wouldn't I need a retune for the 3-stage boost controller? Or does 1 tune cover 3 boost levels, i.e. the maps do not change as you adjust the boost?

[R31Nismoid]

With a PFC it wouldn't, and if you used a ECU that did you'd be paying 4 figures for essentially 3 tunes. Most people simply tune for the highest boost when running a controller meaning that lower boost will be fine as it's not going to be worse off.

I think running 3 boost levels is kinda pointless though, and costly for the controller to do that.

[discopotato03]

Your R31 should have an RB30 in it and I'd be doing everything I could to keep it that way . Bigger engines make it easier to spool cheaper bush bearing turbos so factor that in .

I seem to remember R31s being heavy for a RWD Skyline so keeping the cubes would be good . Your call but finding a twin cam top end and fitting that would be easier and have fewer rego issues IMO .

A .

[sweefu]

With a PFC it wouldn't, and if you used a ECU that did you'd be paying 4 figures for essentially 3 tunes. Most people simply tune for the highest boost when running a controller meaning that lower boost will be fine as it's not going to be worse off.

I think running 3 boost levels is kinda pointless though, and costly for the controller to do that.

3 boost levels is helpful for me, or at least two. For drifting I want to keep the power as low as I can (considering modifications), I'd want a higher boost setting for some fun track days.

I am curious though, I don't understand how the boost increase works in relation to the tune on the ECU, considering the boost controller would be a stand alone unit from the ECU. My house mate has 3 boost settings in his GTR, but he is using an Apexi boost controller, controlled through the PowerFC itself. A handful of friends locally also have 2-3 boost settings. Will the tuner create different maps? I've never heard of changing maps when changing boost. Or is it 1 map to suit all? Seems odd that 1 map could suit 12psi and 20psi. I don't understand how this works, but I know my housemate's car runs beautifully on 15psi and 20psi.

Your R31 should have an RB30 in it and I'd be doing everything I could to keep it that way . Bigger engines make it easier to spool cheaper bush bearing turbos so factor that in .

I seem to remember R31s being heavy for a RWD Skyline so keeping the cubes would be good . Your call but finding a twin cam top end and fitting that would be easier and have fewer rego issues IMO .

A .

Thanks for the response mate!

My R31 is quite light I think. Including jack, tools, spare tyre etc is weighed in at 1280kg. I have since removed everything from the boot, the air conditioning, sound deadening, carpet, interior trim etc. Although I understand I have added more weight from wheels/tyres etc, I think the weight overall is quite light, certainly less than 1250kg. For me, a stock-ish rb25det engine and gearbox is the best option. Turbocharging the stock RB30 is no good because of the weak gearbox, I would need to change to an RB25 gearbox either weay. I am not interested in building a hybrid motor from the time, money and overall difficulty versus installing an rb25det engine/gearbox package. The power and torque will be much greater than my RB30e and the gearbox is much stronger, which is a big plus for me (rb20/rb30 gearboxes aren't very strong imo)

Thank you for your help.

[ARTZ]

You're then sitting on around $1800/$2000... which is pretty much GCG Hi-flow money right there mate - No tune, bolt on and off ya go totally stock looking.

Pardon????

[sweefu]

Pardon????

No tune because that is the turbo currently on the engine I am buying - I am buying a complete RB25DET with turbo/injectors/afm/ecu from a wrecked r33, though the owner of the car is keeping the turbo. If I was to replace it with the exact same turbo - no retune required The comment there was just out of context.

[ARTZ]

Oh now I get it..

Even if you bought the exact same turbo you would have to take the tune in for a check anyway because you have changed other things like the exhaust, intercooler etc. So you may as well factor that into your budget and talk to your tuner first..

But if you jget any other hiflow a retune shouldnt cost 6-800...cause it is already tuned...you would just be getting a "touchup" tune which shouldn't cost more than a couple hundred..Dependant what tuner you go to of course...some will charge you 800 just to walk in the door...others a little more realistic

[jet_r31]

Id rather rather have a Rb30+ T with a small cam rather than a Rb25 turbo any day of the week, but maybe thats

just me...lol

[sweefu]

Oh now I get it..

Even if you bought the exact same turbo you would have to take the tune in for a check anyway because you have changed other things like the exhaust, intercooler etc. So you may as well factor that into your budget and talk to your tuner first..

But if you jget any other hiflow a retune shouldnt cost 6-800...cause it is already tuned...you would just be getting a "touchup" tune which shouldn't cost more than a couple hundred..Dependant what tuner you go to of course...some will charge you 800 just to walk in the door...others a little more realistic

A good point here! My car would have a different exhaust, air intake, intercooler, fuel pump and potentially boost setting (unsure what sort of boost the car was running previously). So a re-tune is probably a good idea, I was a bit wary of using the old tune in any capacity, I don't know if it had problems or not.

At the moment I am looking at Hypergear ATR43SS turbo, it looks to be responsive, works well with the supporting mods I already have, makes more than enough power and almost bolts up to all the stock pipes. This is a big plus for me, as I already have an intercooler kit sorted which lines up with stock RB25 pipes in an R31, and I want to keep the stock manifold.

Id rather rather have a Rb30+ T with a small cam rather than a Rb25 turbo any day of the week, but maybe thats

just me...lol

.

It's much easier for me to install this RB25DET engine / gearbox package all at once, I don't want to go through the process of an E+T conversion, then have to buy an RB25DET gearbox separately etc. I need the stronger gearbox too. I'm not a huge fan of RB30ET motors, i think it takes too much to get it running as smoothly as a lightly modified 25DET, that's my preference anyway. Also from a cost / reliability point of view, the RB25 wins, and I need this motor/gearbox combination to be stable for my next car, RB30ET would not be practical for my next application. I originally had a complete turbo setup ready to go on to my RB30, but decided to sell it for the route I am following now.

I am going to talk to a tuner here in Canberra in the new year, but I was hoping someone could please clarify something for me. If I have two boost settings, for example actuator pressure and 18psi, would there be just 1 tune for the two of them? Assuming it would always run the 18psi tune, and then run a bit rich on less boost? I've never heard of or seen people changing 'maps' when changing boost settings. I plan to have at least 2 different boost settings.

Thanks very much for all of the help guys!

[t_revz]

1 tune, various boost levels is fine.

[AngryRB]

Id rather rather have a Rb30+ T with a small cam rather than a Rb25 turbo any day of the week, but maybe thats

just me...lol

agree.. an rb30 is a different world to rb25, id be building a torque monster with massive under the curve area, in the long run you may well get power hungry and with an rb30 its a much better starting point.