SilverR1

I was testing my car tonight. Just to give you a background I just added:
dp
mp
Apexi FMIC
Power FC
Koyo radiator
Apexi intakes
Greddy catback

So here is the problem. I just got the car out of the shop after getting my 5th gear synchro fixed and installing my ACT clutch/flywheel combo. It did a few runs and it was fine then on one of them while I was really getting into it the car started bucking at about 6-7k rpms. I let off and checked everything and it looked fine. I tried it again just not as hard and it ran fine. Do you think I need to add an HKS twinpower? It seems like it was missing but this is a rotory so I really don't know if rotories misfire like this. I am waiting on some new plugs coming in so maybe that might be it. It's been about a year since I changed them out.

One last question, my injector duty cycle is reading about 94% for just a fraction of a second. I'm assuming this is due to some spiking but normally sits about 89% at wot. I've got a Walboro HP fuel pump to install. Will this help out or should I not worry about that? My a/f still looks fine though.

Thanks for any help.

FD Racer

Yeah I'd say it's time to go with a twin power. What plugs you going with? I'd go with all 9's.

Not sure about the duty cycle question

SilverR1

I really don't understand the whole colder plug thing works. I know that colder are suppose to help prevent detonation but since I plan on upgrading the ignition wouldn't that give me a stronger spark which will increase the spark temp? Please educate me on this one.

maxcooper

Colder plugs make the car harder to start, give a rough idle when cold, and are more prone to fouling. But, if your current plugs wear away quickly (look at the center electrode), you might need to go colder. "Hot" engines need "cold" plugs. If your plugs are too hot, they can contribute to detonation. All 9s works well for many modified cars with bolt-ons and perhaps some porting.

The fuel pump upgrade will not reduce your duty cycle at all without reprogramming your computer. However, if your current pump is inadequate and the pressure is dropping at high boost / high RPM, you can adjust your fuel map so that the duty cycle will be lower. But it won't change the duty cycle at all unless you change the fuel map. The computer does not monitor fuel pressure or make automatic adjustments based on the O2 sensor reading under boost.

-Max

FD Racer

The whole "hard to start" and "rough idle" thing is over rated. At least for me it is. I just recently went to all nines and have been very happy so far with the improved performance with little to no decrease in cold engine operation.
I had a problem with my plugs that started about 2 months ago when i was routinely changing my plugs with the stock 7L and 9T. Soon after i began to notice i had picked up some high rpm miss. Since I didnt notice it imediatly after i changed my plugs i thought that it could'nt have been my new plugs. Well, after trying several things to get rid of the missing with no luck i decided to swap out the 7's in the leadings for 9's. It Totally went away. Who knows maybe I some how fouled those new 7's I installed, or maybe someone dropped them before i installed them.... whatever the case my car runs strong as hell with those nines in there now.

atihun

Did you add all those components at once? I hope not.

If you are using the base map on the PFC, you may be pushing the limits of the base map with a dp, mp, cb and IC. It doesn't feel like boost or fuel cut does it?

What boost are you set at?

SilverR1

I pretty much added all of those at once. I'm normally seeing about 13# but it does spike to 15#. Do you think this is boost cut or fuel cut? I thought the PFC eliminated this? I'm using modified map #4 Tim Benton's maps. Do you think I should use another map?

KZ1

FWI, Tim has HKS ingnition, nbu his maps are basically stock base maps, except for few changes in fuel maps.

atihun

Ok, I don't mean to be mean, but:



What were you thinking? Slap a bunch of stuff on your car and expect it to last? Yes, you did add the right stuff together, but if you want your car to last, and make it easy on yourself when you need to troubleshoot something, add one item at a time. Test it out, see how it runs, then go further.

I am assuming that you have the stock sequential system in place?

Also, what is your PFC set at with regard to boost????????? If it is set at 12psi on the PFC and you are seeing 15 psi ON THE PFC, then it's possible that you may be hitting fuel cut. The PFC is set to do a fuel cut if your boost rises 0.25 kg/cm higher than what you set the boost presets to.

That is definitely not a good boost spike anyway. Are you also possibly seeing boost creep? Some people with an open exhaust will see creep some won't. Depends on their entire system. You can either increase the wastegate pills size or consider getting your turbos wastegate ported.

I don't mean to be mean, and I am the first to admit that I don't know everything about these cars, but if you want your car to last, especially an RX-7 3rd gen, don't just assume that by adding the right parts all at once and setting up your PFC slightly adjusted map that your engine won't implode on itself.

If you are seeing 94% injector duty, it may be time to get larger secondaries, and possibly larger primaries to keep the ratio correct.

I also think that you might want to consider somehow getting the PFC correctly tuned. You will not only make your car safer, but you will be suprised at how much better it will run, and how much more power you will get. I am not sure about your area, but you could send it to XS Engineering and tell them your mods, and they will get the PFC closer to your setup.

Do you have the PFC manual? If not, e-mail me and I will send it to you. It has a ton of great info in it.

Please don't be mad, I am just trying to help you , and if I am wrong, I appologize in advance.

~Attila~

SilverR1

Man I'm sorry. I'll take it all off and sell the car. I'll go and get a Yugo or something. Just kidding. I understand and appreciated what you guys are saying. I am learning as I'm going along. The only way I can find out if things are abnormal is to push it hard a few times. Please keep the suggestions coming. No offense take here.

atihun

I am glad that you didn't take it the wrong way, and that you have a sense of humor

So what are your boost settings?

Oh, and to your original post question, yes, the HKS TwinPower ignition is an important mod when you are pushing the limits, and in my humble opinion a worthwhile one!

Viper jr

That 94% duty cycle is very troubling - you should probably take a hard look at controlling boost until you get some bigger injectors in place. As for the twinpower, it seems that on our cars they can help at almost all levels of modification so it won't hurt to have one, but I really wonder if it will solve this particular problem.

SilverR1

I want to say it is set to the 2nd boost setting that the base maps give. I think it's at .9 bar or something like that. Maybe I'll go back to the first setting. I think it's only .8 bar. Hopefully this will take care of things. I'm thinking about getting RC engineering to bore and balance my secondaries to 1300 cc. Do you guys think this is a good way to go with it. I'm not planning on going to single for at least a year or two. I don't think I will need the 1600 until then. If there are other options let me know. I know that rotory secret will do a swap out for a little less than $300 for the pair. If there is a better deal out there let me know. Thanks.