RB25DET ROM Tuning

[BEST1TUNING.COM]

Is anyone still interested in the ability to tune through the stock r33 RB25DET ecu? This is possible so i would like to know if anyone would still want to go this route. You would have full access to stock ign/fuel maps, ability to scale maps for more boost, control of VTC activation etc. Just like the ROM tuning capabilities of the SR20DET ECU and other nissan ECU's with current tuning support. You could even use an 8 bit emulator for realtime tuning. The ECU when setup will access a single 256K EEPROM for memory and will allow for emulation or multiple reprogramming cycles.

If anyone wants to get more information on givin this a try please contact me. I will also check back on this post and answer questions.

[Kansei240sx]

How did you get that to work, to my knowledge the RB25DET ecu's have a permanently burnt in program that doesnt use a daughter board or something of that sort, im tired i have work in 4 hours.

[bmadd2402]

I would LOVE to have this available to me. I too was under the impression this was impossible, unless you have a totally new ecu you have developed. I would like to know more!!

[Carl H]

r33 ecu is untuneable, plain and simple...i suspect that they are using either modified rb20 ecus or modified z32 ecus...nothing new really.rb20 lacks vtc control and z32 will be looking for egr and a second o2 sensor constantly so you'll always have a cel.i know this company tried to get me to tell them how to tune the stock ecu...

[Sil240]

Carl weren't you working on a tuneable ecu for the rb25??

[Carl H]

yes.i've got the basics down now its time to track down the hardware and experiment .

[Sil240]

Cool Cool.

Besttuning -You should talk to the mods before posting a AD like thread. Unless your doing this for Free, then I'm sure they wouldn't mind then.

But it's good to know there are people working on ECU alternatives.

[BEST1TUNING.COM]

Yes Carl I have talked to you before to see if YOU had the ability to do this. You might want to think more in depth before claiming there is NO WAY possible to do this...I knew there was a way its just who has found it, well, I found someone who knew. Honda ROMS originally come internal to the processor, however there is an EA (External Access) pin (active low) which when fed a low signal, outsources memory...the only good part is HONDA included circuitry for an EEPROM in the mother board. The RB25DET ECU did not include circuitry but will work the same way only it is a more complicated proccess. People for a while could get reprogrammed RB25DET ECU's which involved removal of the processor containing the memory, reprogramming it and re-installing it. However it was a one-time deal now you can continue to edit as many times as you like with only a removal of the EEPROM.

Let me clarify a few things:

This will use the STOCK RB25DET ECU. Period.

As you can see on the website I offer both the RB20DET ECU for the RB25DET as well as the STOCK RB25DET ECU.

YES the ROM is internal however on some processors, there is a way to outsource the memory externaly. The processor will be raised off the mother board to a daughter board, It will then be configured to source an external 256k EEPROM which the file will be burnt to.

The surface mount components as well as shipment and availability of these boards to me make this a difficult process however they are now available to whoever would like to try them.

It was even exciting for me to find and I dont even own an RB25 but I know these have been hard to find and I want to make them available.

Any thing else and I will be sure to clarify to the best of my ability.

I appologise for posting an add-like thread, if the mods would like to move this or delete it thats ok. I guess just e-mail me for info.

[Carl H]

it makes sense the way you did this, but i cant imagine that its cost effective to do this.i also understand how a honda ecu works too but the real question is why did nissan design THIS (r33 rb25) ecu so diffrently than any other nissan, afaik it is the ONLY ecu with this architecture.all other nissan ecus have external memory standard or have provisions for this on the boards.do you have the equipment in house to do this kind of work?SMD components and PLCC sockets especialy suck complete arse to work on, i had to hand solder one the other day and talk about a pain.i do sincerly wish the best of luck to your company but until someone proves that its a truly viable effort i have my doubts.

[BEST1TUNING.COM]

Yes I will definately agree with you on that, it is a real pain even using a reflow bench it is difficult with these components. It is the installation as well as the availability and cost of parts which makes the price tag of the package, but I have tried to be as fair as possible to both sides.

I am also unsure of the reason Nissan decided to design this ECU differently.

I just wanted to give the option, since i dont think many people offer this and its completely up to whoever would like to use it, but it has been tested and used and running a stock ROM it runs the car like from the factory.

I am not trying to "push" this product, just letting people know that it is available now. I am also worried about how long these components will be available to me, seeing as they are only available outside of the U.S. and due to the cost I cant keep many of the components in stock...

-HannaBEST1TUNING.COM

Modified by BEST1TUNING.COM at 12:24 PM 4/26/2007
Modified by BEST1TUNING.COM at 12:34 PM 4/26/2007

[Eikon]

We Mods are always careful to protect NICO's best interests. Normally, we frown on the sales of products from commercial entities unless they have discussed sponsorship with our advertising department.

While this thread may be a little in the gray areas as far as intent.. I think it's a valuable informational thread for the forum.

This sort of conversation is always good as it increases the overall knowledge base of our forum. It also exposes freaks like Carl and Hanna who are clearly too smart for their own good.

To BEST1TUNING.. if you do bring this product to market, please contact us to discuss options for advertising the product on this site. Thanks!!

[Joe]

While this thread may be a little in the gray areas as far as intent.. I think it's a valuable informational thread for the forum.

thats exactly why i havent touched it.

[300Plus]

after talking with a few ppl about this I was told to use a maxima ecu the VG30de I hear it only has one O2. What do you guys think about this option? I'm dumb in this area but def wanting to learn!

[BEST1TUNING.COM]

Thanks to the mods for keeping this up here...its motivated me to go into a little detail about using the RB20DET ECU on the RB25DET for those who want to do it on their own.

Like Carl stated, there are a few options for RB25 owners. You can use different ECU's however my experience has been best using the RB20DET ECU with an RPM relay switch to control VTC, since it is only the VTC which is lost by this ECU. Besides that, it is mostly plug and play If you have the right ROM setup and proper tune.

For those of you who would like to try this on your own, I will breifly take you through it...as my products are mostly for people unwilling to give it a go on their own. Since ECU tuning is a step outside the mechanical area of Automotive tuning, it can be very unfamiliar and frustrating...but always interesting.

The RB20DET ECU circuitry is very similar to the RB25DET ECU in the sence that it can handle all controls of the RB25DET excluding the VTC. So with that said we know that its a pretty good platform to start with, requiring no rewiring beyond the VTC.

The ROM programmed to the RB20DET ECU is specific to its processor, RAM, I/O controllers and other circuitry in the ECU so we pretty much have to leave the "instruction code" of the memory alone. However the coded "values", such as the VQ table (a lookup table of many values based on voltage seen from the MAF sensor, blended with a formula, to think up a theoretical load), High Fuel table (rpm and load based table to determine fuel delivery), High Ign Table (rpm and load based table used to determine ign advance), k value (a multiplier used in formulas necessary for fuel delivery calculations), and a latency value (value used to compensate for the time it takes the injector to open befor it sprays fuel) need to be exchanged.

There are many more tables, some known, some unknown, however these are the most important of the discovered ones when blending the RB25DET ROM with the RB20DET ROM. The next step is to replace the RB20DET maps with the RB25DET maps. To do this you will need a ROM editor to be able to copy the desired maps over to the other ROM. The VQ map is specific to the MAF sensor and this is the table that needs to be swapped over when swapping MAF sensors such as a z32 into an SR ROM. Each MAF has its own unique VQ table. Since we are switching over from an RB20DET MAF to a RB25DET MAF, we need to swap VQ tables.

To get as close to the RB25DET tune as possible before fine tuning, we will need to transfer over both the High fuel and High ign tables in to the RB20DET ROM. Once this has been done there are the K value and the latency value to be changed since the latency and k value are specific to the injectors and the RB25DET uses 370cc while the RB20DET only uses 270. Luckily Nissan decided to make both the RB20DET and the RB25DET use High Impedence Injectors, or else more modification would be needed. Since the RB25DET value has proven to be too high...simply divide 270 by 370, convert the RB20DET k value from hex to dec. and multiply the result of the devision by the dec. k value to get the new dec. k value and convert back to hex. You can keep the stock RB20DET latency value but adjust it if you experience a rough idle.

When I first did this and started the car it fired right up...but definately needed further tuning. A small tip for anyone who decides to give it a shot is adjust the K value untill you get your AFR close throughout the load and rpm range, then fine tune in the fuel maps.

To fully complete this project you will need:

Soldering iron etc: $50Rom Burner: $100Emulator: $100Software: FreeRB25DET ROM dump: researchRB20DET ROM dump: researchadr. Files to open the ROM's in an editor: researchRPM switch for VTCAlot of Free time

I have to say that an SAFC tune or an expensive Power FC tune, which doesnt even come with software, is no comparison to the quality of a tune through a stock ECU.


Modified by BEST1TUNING.COM at 9:59 PM 4/26/2007

[midnightsliding]

sounds hard. i would like to pay you to tune mine..

[Fearsome_tea]

Not impossible. We have been doing them for years. The chips are like 20 dallors a pop but you can not rewrite them(one time use).

[Carl H]

if you have to burn a processor 10 times to get the tune right then thats 200$ wasted...so while it isnt impossible its not realistic as its too expensive.

[Fearsome_tea]

Thats why we tell ppl to go with a full stand alone ie PFC, FCON, SDS, MOTEC etc. Better tunning capabilitaies. My friend charges about 300 bucks for a tune. The software he gets free.

[300Plus]

What about using a Maxima ecu and eproming it???

[BEST1TUNING.COM]

Well with the RB25DET ECU and board all you have to do is burn an EEPROM chip or use an Emulator and do it on the fly. I dont see how this would be any more difficult than updating any other ROM tuned ECU. I have always known about the programmed proccessors and that is not cost effective at all, but now its a single 8bit 256k EEPROM.

This is gonna have to stay a technical thread though any one who wants to talk about a tune from me will have to do so through e-mail.

[300Plus]

I'll be the dumb one in the crowd and ask if you can make a "write up" with pictures. This would be a great option for those needing a cheap programable ECU.

[Carl H]

i dont suppose your friend is matt @ motorworx?

Thats why we tell ppl to go with a full stand alone ie PFC, FCON, SDS, MOTEC etc. Better tunning capabilitaies. My friend charges about 300 bucks for a tune. The software he gets free.

[BEST1TUNING.COM]

I'll be the dumb one in the crowd and ask if you can make a "write up" with pictures. This would be a great option for those needing a cheap programable ECU.

But that would take all the fun out of DIY I am suuuuper busy this time of year...if I had free time i would do this.

[Fearsome_tea]

i dont suppose your friend is matt @ motorworx?

No, don`t know that guy, except from the the Yon site.

[RBKIDD]

rb20 tuning issues

i had just put a gt3071r garret turbo and 75lbs injectors and a z32 mas and a set of cams not sure wut size to get maybe yoou can help me wit that to to let me no what would work well.but ne way the speed shop i bought the parts from told me that i cant start it with the stock rb20 ecu with the upgrades i put on .what should i do how should i start it with out bringin the car to a speed shop because i dont want them to start hitting me with their labor charges to start diagnosin the car if it doesnt start when i bring it in to get tuned please help me thanx mike kidd

[Yellow4g63]

There right you can't start the car with way bigger injectors and a differnet MAF. You need to burn a chip for those mods and tune it.

[USMCgetsome]

I HATE U GUYS! i researched this back in 2004! Here's the link. I better get a thank you from somebody! lol.

zerothread?id=110940

[RBKIDD]

GREAT THANX FOR THE HELP.SO I CAN JUST SEND MY ECU TO ONE OF THESE COMPANIES TO GET IT REFLASHED N TELL THEM WHAT I HAVE DONE TO THE CAR AND THEY WILL BURN THAT ONTO MY ECU?THEN IT WOULD B SAFE TO START THE CAR?THEN I WOULD BRING IT TO GET A DYNO TUNE FOR THEM TO TUNE WHAT?WHAT COMPANY DID U GO WIT FOR THE REFLASH AND HOW LONG DID IT TAKE AND WHAT DID IT COST?

[RBKIDD]

GREAT THANX FOR THE HELP!

[USMCgetsome]

gents i never did send in my ecu for the new pga chip. You can hit up those websites and email them. It's been quite sometime since anyone brought this back up.