Aarkaah

iTrader: (5)

All,

I picked up a tastefully modded 1993 Rx-7 VR with a Jet Power Chip installed. While I do enjoy the car it tends to backfire every once in a while when driving. My local shop says this is normal given the mods (downpipe, intake etc...). I am however concerned it may mean tuning was less than adequate.

Anyone got any experience with a JET Power Chip? Recommend keeping it or swapping it out for an Apexi Power FC unit and re-tuning the car? As it stands I have no idea how the car is running and do not like this risky set-up.

Regards

Double-A

EP RX-7 steve

Is it off throttle? Is it shooting flames from the exhaust?

Aarkaah

iTrader: (5)

yes. Typically off throttle or after some revving. (Not spirited mind you).

No flames that that I know off. None aggressive driving can still lead to symptoms.

cr-rex

iTrader: (114)

No idea what a jet power chip is but it sounds like something you should get rid of. Go pfc and get it tuned to run properly. If you're backfiring that easily, you're dumping fuel.... an over excessive amount of fuel. Your car isn't running anywhere near as good as it can. A pfc or adaptronic with a proper tune will get you sorted. You'll also need a wideband

Aarkaah

iTrader: (5)

Thanks man. Ok I will go after the PFC. Question though, will the PFC hook into the Wideband or is the Wideband just to give me an idea of the Air-fuel ratio and then I have to adjust via PFC until everything is spot on?

insightful

the wideband is just an auxiliary input. the PFC is an antique, it can't tune your car with a target AFR and the wideband signal, all tuning you must do yourself.

Aarkaah

iTrader: (5)

Insightful... thanks on your input... Your statement "PFC is an antique" leads me to believe there is a better solution or do you say so because it can't dial-in an ideal tune based on targets and wideband readings?

I was under the assumption (ahem)... that the PFC was the tried and tested way to go on the forums for a mid-level modded car?

Understood on the tuning, I guess this means that the Apexi base maps are decent but not great enough and that tuning to each car's mods is a better approach - correct?

Thanks in advance.

insightful

adaptronic would probably be where i would turn, for not much more than a PFC it has features like auto tune that can help you get the car closer to final mapping, but autotune isn't ever going to be a perfect tune and will always require some touching up. i also don't trust auto mapping in aggressive boost level areas, up to a few psi of boost its unlikely to cause engine damage.

adaptronic makes plug and play ECUs, so i'd consider it a step up from the old days of the PFC for those who don't want to gut their engine harness and build one from scratch.

not that i like elliot or plugging for them, but the ECU fills a gap.

EP RX-7 steve

Too rich, A custom tune is way better than a cookie cutter.

I bet you are throwing flames out exhaust, don't freak out if somebody at a stop light tells you!

cr-rex

iTrader: (114)

you would only need to hook the wideband to the power fc for datalogging purposes but not at all required. so yes, its just to tell you afr.

theres nothing wrong with the power fc. its just the nature of some of the members here to refer to "older" equipment in such a manner that makes it seem as though its some sort of garage experiment that people used because there were no other options. the power fc is still very capable and more than sufficient for most cars. the power fc base map is good enough to drive on for a VERY short time. its set up to be very safe until a tuner goes in there and actually tunes it. by all means you CAN drive on it all you want but the results wont be good.

the power fc is a circuit board in a box and by no means is required to be bought brand new. there are PLENTY of used ones for sale here on the forum for ~600 and sometimes less. an adaptronic starts at almost double that. the adaptronic is much more advanced than the power fc but that doesnt make it better. its all based on the needs of the owner and the set up. if hes got the money for it then cool, go adaptronic just because. its an ecu that has more features than most can or ever will utilize. all that computing power to run bolt ons

do some research on the two and determine what you need/want from your ecu. the adaptronic is cool with all its safety features and automation and so on. the power fc has been around for a long time and has gone pretty much unchanged. it does its job. youll be happy with either.

BLUE TII

iTrader: (9)

The Jet Power Chip application for the FD RX-7 is just an overboost fuel cut eliminator.

The ECU is and is running as normal stock FD except one of the factory safeties is bypassed by clamping the MAP sensor output to the ECU.

Products For Model ? Jet Performance Products

insightful

he seemed interested in wideband feedback, and IMO $500 spent on a used ECU versus 1k for a brand new and more advanced one does seem like a few dollars more to most who consider their ECU an investment. the powerFC is definitely capable, but it's also a bit clunky and unsupported now.

we also forgot to mention it's getting more difficult to find links to download FCedit or other programs capable of running the PFC, as well links for maps have all but gone. there's also the addition of purchasing a datalogit which are also limited, no longer made and getting more difficult to find item that adds $100 or more to the cost of even a used ECU in order to program it beyond the basics of the hand controller capability.

used units don't always work either, the hand controller is prone to failure and the ECUs are not bulletproof, plenty of people have purchased secondhand PFCs only to wind up with broken units that they spent days to weeks or months trying to diagnose.

so yeah, i do consider the PFC a bit antiquated still, yeah it is cheaper but is it worth still mentioning? it is, but i merely pointed out another viable and arguably better option(no argument if cost is less of a problem).

DR_Knight

iTrader: (23)

I run PFC but my next ecu may be a newer haltech with the auto tune function. Just feel it’s easier to street tune while daily driving. But..... it’s better to learn an ecu you have to do everything manually so you know exactly how it works.

Btw, got into an argument with a 13b na-t guy who will “take on any 4 port turbo rotary”....... and he stated PFC was a crap ecu..... my return comment was the re amemiya fd..... which still runs it to this day IIRC. Just saying

insightful

i never said the PFC was a crap ECU, people seem to be putting words in my mouth. i said it was antiquated and doesn't offer as many benefits as a newer and more modern ECU as well as product support. the PFC is no longer made and getting internal repairs done is an act of attrition.

anyone who has built a number of rotaries knows that the 6 port engines aren't a good platform for big numbers, how many 6 port engines have broken 500 or even 600whp? could probably count on one hand the numbers around here. how many have gone higher on a 4 port? too many to count, the 6 port engine has turbulent airflow and poor port timing for high boost. add in if the owner retains the high compression rotors they are severely limited by detonation on lower octane fuels.

anyways, it was a simple suggestion that people have taken to a new level. i have built cars with the PFC and made some rather impressive and reliable numbers btw, so i'm not quite a hater of it, just a realist that there is better alternatives.

Aarkaah

iTrader: (5)

Whoa! This is a lively forum. Thanks for all the comments guys.

I think the best note was to be mindful of gambling with used units. (I don’t have the time to waste on this)

I also don’t want to plunk $1,000 bucks down on an antiquated system.

So I think a little more research is warranted on the forum before selecting the replacement ecu brand.

Adapteonic, haltech, Pfc etc. ?

Aarkaah

iTrader: (5)

So in other words nothing tuned for the addons I have? I just got the car this month and I am going through it in the next two weeks to remove any suspect add-ons.

Jarod R32

Depends on where you are. There are shops that specialize in tuning different ECU's. Jet power chip isnt a full ecu, Imo I would contact a local shop known for rotaries and see what they suggest.

Aarkaah

iTrader: (5)