Hello,

I am about to purchase the NepTune RTP system for my car, being a college kid this is a fairly big investment on my part, so I was hoping some of you could verify what I have found out through research before I purchase. I am looking to street tune my mild engine mods, and set up for a future turbo install. My main goal is to learn about engine management.

This is what I am looking to purchase: http://www.phearable.net/shoppingcar...ages-p-40.html

And a chipping kit off ebay (unless I should get one elsewhere, didn't seem to be anything special about them): http://www.ebay.com/itm/P28-P72-P73-P30-p06-p05-ECU-Chipping-kit-OBD1-HONDA-VTEC-CHIPPED-chip-socket-/170983154703?pt=Motors_Car_Truck_Parts_Accessories&hash=item27cf63e40f&vxp=mtr
Anyways, from my research I have determined the following, does any of thise seem wrong?:

• My car (1995 Del Sol SI) uses a OBD-I P28 ECU.
• Any standard chipping kit and the NepTune RTP should be all I need as far as ECU goes. (Obviously wideband and other accessories will be needed outside of ECU)
• Once I chip and install the RTP in my ECU my ECU will retain the stock map I am currently running, but I will be able to modify it. (perfect for learning/tuning for the mild mods I have).
• My car will still run like stock until I start changing things.

Additionally I have the following questions I am still not fully sure about:

-I have not found a clear guide on installing a wideband O2 sensor to work with the NepTune system, could anyone point me in the right direction?
-Should I purchase a chipping kit from any place in particular? It appears to be very standard electronic components, so it seemed best to just go with the most convenient and cheap.

Thanks for you patience, I understand a lot of this is searchable, and have spent a fair amount of time searching. I just want to verify my own research before taking the leap.

-Matt

 

When you purchase a Neptune RTP, it includes the socketing kit, no need for purchasing another.

It's not perfect, but pretty decent
http://www.xenocron.com/install/Xeno...etup-Guide.htm

The RTP doesn't exactly retain the same stock map as the p28 you have. It's that mapping, but in a modified stock code, essentially it's stock BUT it doesn't work exactly the same

 

Thank you for the information, I really appreciate it.

Could you expand a bit further on how the modified stock code is different? I am mostly concerned about how much work I will need to get my car up and running? (I have a motorcycle for alternative transportation, and will be buying a winter vehicle, but getting it running quickly would be nice so that I have more time before winter to experiment with street tuning.)

Also, if anyone notices anything I am missing, I would massively appreciate any tips. This whole project is entirely to learn from (as are the rest of my car modifications), I am trying to build practical experience with embedded automotive systems as a resume boost outside of school and internships. (I am a senior Computer Science and Electrical Engineering Technology dual major).

Thanks again,
Matt

 

chris (xenocron) can probably explain it a bit better than me, and correct me if I'm wrong, but basically the difference is that all obd1 Honda boards use slightly different coding for the main memory, but chippable ecu's (not all Honda ecu's are chippable) have a separate section on the board to add the chip stuff to and uses slightly different but universal coding. theoretically the p28 base map is identical to the stock p28 mapping, but due to slight coding differences there may be some slight variances in a few things.

for ease of use, I would suggest installed a removeable pin header on the J1 location. when installing any type of chip kit, jumping the two terminals at J1 on the ecu board causes the ecu to read from the add-on chip/system, and no longer reads from it's main memory. removing the J1 jumper causes the ecu to read from its main stock memory again even if a tuning system is still installed. most people just bridge the two terminals with a small section of wire, I usually use removeable headers though just in case. and in your situation because you're using the original stock ecu with a stockish engine setup, it'd be wise to do so you can jump/unjump it anytime you please.

 

this is the J1 terminal I'm talking about in my ecu, the red thing is the removeable jumper. you can remove it and slide it back on offset so it's only on one terminal so you don't lose it.

 

If I am reading right then, apart from small differences in the execution of the fuel maps (similar from jumping between various compilers in programming) the stock p28 fuel map should be functionally identical to my stock ecu map? (enough to get down the road and experiment with street tuning anyways.)

Thanks for the tip on the jumper, great idea. I think I may actually have a jumper, or maybe even a appropriately sized switch already laying around.

So essentially I can reconnect that J1 jumper at any time and go back to the stock map as a failsafe? That is great. I wasn't sure if the RTP replaced the stock memory during the course of installation.

When you say not all ECUs are chippable, do you mean even within ECU types? Like, are some p28s chippable while others are not? I was under the impression that my Del Sol had a p28 and all p28s where chippable.

 

The RTP holds the NepTune codebase. The NepTune codebase is based on the P72 ECU. P28 maps in a P72 codebase will not run identically to a stock P28 codebase. It will run fine, likely a little rich. If you're going to street or dyno tune then this really isn't an issue.

Your P28 can be chipped.

 

the following ecu's can be chipped (all ecu's that have these codes):
p06, p28, p30, p72, p75, pr4
which basically means any obd1 del sol, civic, or integra.

all prelude and accord ecu's can NOT be chipped.

and just a correction, having j1 jumped makes the ecu read from the add-on tuning system, removing the jumper reverts it back to reading from the stock mapping built within the ecu, completely ignoring the add-on tuning system

 

If your street tuning i suggest a wideband 02 and start researching how to read spark plugs..

 

Yeah, that is the next step. I just want to get the 'big' purchase out of the way first. Currently my engine only has:

AEM Intake
Skunk2 Manifold
Skunk2 Throttle Body
Headers
Tucked 2.25 inch exhaust (ends in a turndown in the middle of car)

I figure I can play with tuning the car once I have a wideband pretty safely with these minimal mods. Once I get a build that is more 'final' I will have it professionally tuned, but it is a minimum of 4 hour drive to nearest tuner. I figure until then I will just learn, and stay conservatively rich for everything except partial throttle cruising.

Need to research a lot more first though.

 

headerS? how many headers do you have?

 

All of them. :D ...Doh

 

Its not that difficult just take baby steps..

 

Thanks for all the help everyone. Purchased my NepTune RTP, should be here in a few days. While I am waiting, does anyone know good resources that are geared to street tuning specifically? I am searching and finding things, but I am sure I missed things/found misinformation.

Also, is there anyone here who has had any results with street tuning without direct access to a dyno? (I live rather far away from any sort of dyno). From what I understand it is possible to get a conservative and reliable tune if not maximum performance from street tuning? My main goal is just to learn, getting great numbers is very much secondary. I have been reading a lot on theory, but I would love a guide that catered to tuning on the street?

 

You made a good choice for your tuning platform. You can read the Crome manual in my sig (free), chapter 7 and 8 cover street tuning. There are more features in Neptune and the layout is different, but the tuning concepts are the same (telemetry = graphing, or VirtualDyno is a decent tool also).
Many of my clients prefer to tune on the track they race on versus using a dyno, so all the real conditions are present. It can be done safely and effectively with proper tools, education and practice.
Obviously a dyno is safer, especially when you're learning since it's a very distracting process. Try to have someone else drive, and just tune copilot so you have both eyes on the data - and both ears on knock!

 

I think ive had decent luck for street tuning my first car.. I just used the hondata help files.. Just make small changes to get the hang of things first.. Ive been to the track twice but never tuned at the track..

 

So I just got my Neptune RTP in today. Thanks for all the input and answers, really appreciate it.

Now I am in the process of finalizing my turbo setup to prepare for a winter build/tune/ect. I am shooting for 200-220 horsepower at the end of this stage of building, but I want headroom in my fuel system in-case I decide to go farther later on. To that end I am looking at 500cc injectors, and a 255l fuelpump. My question is, even though 500cc injectors are bigger by a large margin than I need for ~200hp, will I run into any issues using them? Such as trouble idling, or power partial throttle response?

From what I have gathered in research that sort of trouble doesn't really start popping up until your running 750-1000cc injectors? I figure this way it will give me a wide margin of headroom for more power later, while not being so large as to cause major issues? Let me know if I am going about this wrong.

Thanks everyone, sorry if this is reviving a dead thread, I just thought it better than making a new one.

-Matt

 

you are correct in saying the issues don't typically arise until you start using 750cc-1000c injectors. you'll be fine with 500cc, though I'd recommend 550's as those are more common, and have a bit more potential.

 

oh also, if you get a 255 walbro, make sure you get the 255HP, which stands for High Pressure. it flows higher volume at high pressures than the standard 255.

 

Thanks a lot man, sounds good. The only other question I have is should I get the high impedance or low impedance types? Beyond availability and a resistor box is there any reason to choose on over the other? I would like to avoid a box if possible for simplicity.

 

I also use a jumper on J1 for all my chipped ECUs but in the case of Neptune RTP running on a Demon, the board hides J1 so you'll have to pull it out to "unjumper" J1

 

I've ran ID1000 saturated injectors and passed emissions with perfect idle, it's all in the tuning. Most larger injectors have a longer dead time is all. Peak & hold have a more consistent response at high load, but saturated are generally ideal for Honda ECUs since the ECU drivers are meant for high impedance. RC makes a saturated 750cc injector that works rather well, but the 255HP is overkill IMO. 45psi rail pressure is perfect for most applications boosting under 3 bar.

 

I ended up getting a really good deal of used 450cc DSM injectors, so I am going to go with them. Researching resistor box options now, but I can't see to find a good clear guide on making a plug and play box.

For the sake of not having a extra box in my engine bay, I am considering soldering resistors in line. I am looking into proper impedance and wattage resistors, but any advice would be great.

-Matt

 

I've always used the 10ohm ceramic resistors from radioshack, work flawlessly. I forget the wattage on them, let me see if I can find em online...

edit: 10ohm 10watt...
http://www.radioshack.com/product/in...watt+resistors

 

Cool, I think I am gonna do that, since it's cheaper than a box, and less ugly. Be easy to undo anyways. Really, if I wanted to make it swappable, all I would need to do is also solder in some spade terminals on either side of each resistor, then just jump over them when I want to remove the added resistance. A resistor paralleled with a piece of wire is effectively not even there (well, technically the circuit would have even less resistance than the wire alone...be w/e).

With that out of the way, now moves on to reading up on my LC-2 wideband. Gonna hopefully install that and neptune RTP this weekend, fuel pump in next few weeks, then do turbo install over a weekend. Woo!

Thanks for the continued information everyone!