Rb20/25de+t Turbo Conversion Detonation Issues.

[Paulusc44]

Hey all,

Have just completed my R32 RB25DE+T setup which consists of:

RB25DE block + head from an A31 Cefiro

Walbro 255 LPH fuel pump

New OEM fuel filters

RB20DET Injectors, with actory fuel pressure regs and factory fuel rail

RB20DET AFM

RB25DET NEO T28/30 Turbo with factory internal wastegate, factory manifold, oil + water lines, factory dump pipe

F.M.I (Stock GT-R size) with 2.75" Stainless piping, factory air intake

Factory coils with new OEM plugs

Chipped EPROM (With what I now suspect is a pretty poor tune..)

Have taking it for 2 test drives now and it drives sweet, nice and smooth etc BUT at around 4-4.5K RPM the engine begins to detonate, which gets heavier with more throttle applied.. anything under about 4K RPM and its nice, torquey as and builds boost nicely, however go to squeeze the throttle on after that and detonation occurs..

My next steps are to gap the plugs to 0.8mm instead of the factory 1.1mm..

Add a decent dose of fresh 98

Try a friend ecu which runs on a very similar setup and see what happens above 4.5 K RPM..

I know this type of conversion has been done a million times here in NZ and I bet its no different in Aus so theres plenty of info out there im sure, detonation on the turbo conversions seems to be the most comonly encountered issues..

So whats the best angle of attack from here? What have you guys tried thats worked/not worked? Just keen on a few different viewpoints or even links etc..

Cheers

[GTSBoy]

You will possibly be running out of injector. 20DET injectors are usually only good for ~190rwkW at the max. With your decent pump you might be better off, but everything really needs to be tickety boo to push that far.

A burnt EEPROM tune from where? By who? Probably just has too much timing in it for an NA CR with boost on top.

[Paulusc44]

It was done by a tuner over here in NZ, A place called speedlab.. Im not convinced its the greatest tune to be honest.. I have a couple of other ecus which I can try out just too see what sort of a difference they make, Im thinking about also looking at a rising rate fuel pressure reg?

[GTSBoy]

Im thinking about also looking at a rising rate fuel pressure reg?

Dude, it's not 1990 any more. Don't f**k about with bandaids. Buy some modern injectors, get a Nistune installed in the ECU. You will thank me and yourself both if you do because EEPROM tuning is maximally AIDS ridden and you will hate yourself trying to fix tuning issues that way.

[Dose Pipe Sutututu]

I would retard the CAS if you want to do anything to protect the motor

[Paulusc44]

Ok sweet as,

Ive got a mate coming around in an hour or so with a ECU thats been tuned by a reputable EPROM tuner in Auckland NZ.. Im not sure about Aus but EPROM tuning has come along hugely here in NZ over the last few years, guys are able to get great results with eproms and a dyno..

Anyways bit of a question, Im going to adjust my CAS to the maximum retarded timing, to do so do I move it all the way to the right? (Clockwise)? As this is the same way as the engine rotates it would retard timing?, right?

And is there any adjustments I can make to the TPS that relates to timing or afr's?

Cheers again guys

[GTSBoy]

Um, people have ALWAYS been able to get great results with EEPROM tuning and a dyno. It's just that as a method it sucks balls and has been replaced by about 30 other more efficient and effective ways to get the same result.

Do not adjust your timing without hooking up a timing light so you can see what you are doing. As a bonus, when you have a light on it it doesn't matter of you don't know which way to turn it because you receive feedback instantly.

And no, there are no adjustments you can make to the TPS that will help you.

[blind_elk]

It was done by a tuner over here in NZ, A place called speedlab.. Im not convinced its the greatest tune to be honest.. I have a couple of other ecus which I can try out just too see what sort of a difference they make, Im thinking about also looking at a rising rate fuel pressure reg?

Was it done on a dyno? Or this mob figured "this should work"?

Tunes ain't tunes. Get it onto a dyno if you are going to play around with non-standard setups.

[Dose Pipe Sutututu]

Judging by the end result I doubt the OP has room for an aftermarket ECU and a proper tune, thus I suggested he just retard the timing to prolong the motor until he's able to get some proper ECU or even a Nistune

[Paulusc44]

Hey guys,

Had my mate around last night, He bought several tunes on His laptop, and I used an ecu that also had a Nistune feature pack attached.. (which ofcourse allows for the VCT etc from the S2 eng)

However because my Engine is a S1 we couldent get the tunes to load correctly, the feature pack did not want to delete.. Nistunes have been available in NZ for quite some time, but theyre getting alot more exposure now than they used to, theyre an fantastic ecu and have proven results but the only trouble here in NZ is the tuning.. Alot of guys just arent in touch with Nistune software..

Anyways.. My mate returned home where He has proceeded to load a tred and tested tune onto and EPROM which I will then insert into my EPROM socket.. We have full diagnostics etc so we can see exactly how safe things are..

Also, I slighty tuned my CAS last night, retarding it by around 3 degrees.. Running slightly improved, but is it obvious that the original tune just isnt up to scratch, will let everyone know how I get on later tonight.. I have been in touch with a Nistune distributor over here and can get one for a relatively good price

So were on the right path there, Im still intersted in safe-proofing the setup further, so could quite possibly end up upgrading coils/plugs and FPR's... Some tried information in this category would be great? Do people generally prefer a RR FPR for this type of application? or a simple 1:1 ratio FPR such as a Tomei type s or similar?

Once again guys any infos appreciated, and cheers for the input so far

[KiwiRS4T]

You cannot rely on any mail order chip. There are no good suppliers and Speedlab are far from Nissan experts. . Preferably you need a Nistune or aftermarket ecu but there are tuners able to make a chip for your car tuned in your car (on a dyno or on the road). Plenty of people say "my car runs great on my mail order chip" but they haven't dynoed it. If you can hear detonation its pretty bad but if you can't hear it without the right equipment it can still be bad enough to wreck your engine.

Stock FPR should be fine if you can actually tune your engine. Yes gap your plugs down. What plugs are you running? Try giving your coils a good clean and spraying with insulation if you can't afford quality new ones atm.

[Paulusc44]

You cannot rely on any mail order chip. There are no good suppliers and Speedlab are far from Nissan experts. . Preferably you need a Nistune or aftermarket ecu but there are tuners able to make a chip for your car tuned in your car (on a dyno or on the road). Plenty of people say "my car runs great on my mail order chip" but they haven't dynoed it. If you can hear detonation its pretty bad but if you can't hear it without the right equipment it can still be bad enough to wreck your engine.

Stock FPR should be fine if you can actually tune your engine. Yes gap your plugs down. What plugs are you running? Try giving your coils a good clean and spraying with insulation if you can't afford quality new ones atm.

I know I cant rely on any Mail order chip haha.. Im not new to this.. I knew speedlab werent experts by any means but I am suprised at just how poor the tune is.. Its shocking.. Luckily I have a few tried and tested Nistune maps as well as a couple of others by private tuners here in Auckland, along with all the electronics required for road tuning, which I should be doing this afternoon..

Im currently running the standard BCPR6E NGK which im pretty sure run a standard gap of 1.1mm which I was going to reduce to 0.8mm? My coils are in great condition and have just been cleaned so for now they will be fine. And as for the FPR's.. Im running an A31 Cefiro RB25DE which unlike the R32 RB25DE engine come with twin FPR's from factory.. In this instance is it only nessacary to upgrade the front FPR? aka the one that feeds the engine with fuel?

Thanks again boys

[Dose Pipe Sutututu]

reducing gap won't fix any detonation issues man

[KiwiRS4T]

I know I cant rely on any Mail order chip haha.. Im not new to this.. I knew speedlab werent experts by any means but I am suprised at just how poor the tune is.. Its shocking.. Luckily I have a few tried and tested Nistune maps as well as a couple of others by private tuners here in Auckland, along with all the electronics required for road tuning, which I should be doing this afternoon..

Im currently running the standard BCPR6E NGK which im pretty sure run a standard gap of 1.1mm which I was going to reduce to 0.8mm? My coils are in great condition and have just been cleaned so for now they will be fine. And as for the FPR's.. Im running an A31 Cefiro RB25DE which unlike the R32 RB25DE engine come with twin FPR's from factory.. In this instance is it only nessacary to upgrade the front FPR? aka the one that feeds the engine with fuel?

Thanks again boys

I know I cant rely on any Mail order chip haha.. Im not new to this.. I knew speedlab werent experts by any means but I am suprised at just how poor the tune is.. Its shocking.. Luckily I have a few tried and tested Nistune maps as well as a couple of others by private tuners here in Auckland, along with all the electronics required for road tuning, which I should be doing this afternoon..

Im currently running the standard BCPR6E NGK which im pretty sure run a standard gap of 1.1mm which I was going to reduce to 0.8mm? My coils are in great condition and have just been cleaned so for now they will be fine. And as for the FPR's.. Im running an A31 Cefiro RB25DE which unlike the R32 RB25DE engine come with twin FPR's from factory.. In this instance is it only nessacary to upgrade the front FPR? aka the one that feeds the engine with fuel?

Thanks again boys

Plugs should be fine.0. 8mm gap is a good idea anyway. Sure you have 2 FPRs? The dampers look very much like FPRs. I have a GTR OEM fpr you can have (actually you can have the whole rail if it fits your setup). Just to be clear the fuel feed goes to one end of the rail and the regulator goes on the return end.

[STATUS]

Book into a tuner put it on dyno... live tune it..... job done... simple.

i have around 13000 tunes in my laptop and not one will suit your setup... no one on earth will have a satisfactory "tune" to drop in your ecu..

[Paulusc44]

Ultimately the idea is to get the thing onto a dyno, however Im currently living about an hour north of Auckland, there are no such facilities around.. Ive been in contact with a few dyno tuners in Auckland and have a good idea what Im aiming for and how much it will cost. I wouldent have the balls to drive this thing for an hour the way its detonating above 4K RPM, even approaching 4K RPM it can be tedious, honeslty this "tune" is a joke.. Im just trying to get the thing to a more satisfactory state before I finally dyno tune it properly..

Plugs should be fine.0. 8mm gap is a good idea anyway. Sure you have 2 FPRs? The dampers look very much like FPRs. I have a GTR OEM fpr you can have (actually you can have the whole rail if it fits your setup). Just to be clear the fuel feed goes to one end of the rail and the regulator goes on the return end.

That would be mint man, does your rail still have injectors attached by any chance? If I was to send you my address and pay P&P would you be able to send it too me? Thanks heaps bro

[Paulusc44]

Just a question to anyone else out there that knows.. Because the standard R32 GT-R and R32 RB20DET engines run the same standardized Nissan fuel pressures.. (2.5Kg/Cm2,3.0Kg/Cm2) Will installing a GT-R FPR provide more fuel??

[STATUS]

Just a question to anyone else out there that knows.. Because the standard R32 GT-R and R32 RB20DET engines run the same standardized Nissan fuel pressures.. (2.5Kg/Cm2,3.0Kg/Cm2) Will installing a GT-R FPR provide more fuel??

no the factory RB20 reg is fine for 350rwkw plus... you have a tune related ignition problem.

[Jordy32]

Tow it to a tuner?

[Paulusc44]

no the factory RB20 reg is fine for 350rwkw plus... you have a tune related ignition problem.

Cheers for the info on the FPR.. I figured that if both RB20DET/25DE and 26 FPR's operate at the same stock pressure It wasent going to change anything..

Haha once again guys Im not looking to perfect anything in my driveway, Im just looking to better this current "tune" before I can get either a Nistune or Dynoed EPROM.. Things such as upgraded coils/correctly gapped plugs, upgraded FPR ect arent exactly backwards steps either although some would say unnecessary without an Injector upgrade etc..

Youve pretty much confirmed what I suspected to begin with, that being that "Mail Order Chips" will never perfectly run any setup, Dynos are a necessity for this. I never expected to perfect anything with any thing Mail ordered but I am surprised that the general attitude towards EPROMS is still that without a dyno theyre a waste of time.. I honestly thought that with the amount of interest shown in RB turbo conversions and the sheer amount of people that now own an RB with stage 1/2 mods that buying a Mail order chip to suit the basics (Intake, Exhaust, F.M.I.C etc..) and getting a relatively good state of tune would be a go. (You know when you think about the amount of people with an RB20/25DET with an basic exhaust, intake setup etc..)

Cheers again for clearing things up, always good to know theres people out there with adequate knowledge that dont mind giving you a minute or two of their time