RobEvo5

Need more fuel for more boost - Thought about larger primaries, but I am a novice tuner and it looks like getting good idle is not that easy but not impossible. I also need to consider omissions at MOT time time as well.

So now looking at sticking with my 550 primaries and going for some 1200cc secondaries.

Few questions really.

A. Best place to buy in the UK or accross the wate, or any one got some good second hand ones?

B. Are they a straight replacement for the 850's and NO machining needed to rail ?

c. For say 1200cc's where abouts do my settings need to be on the PFC ?. am I right in thinking 64% and do I need to adjust the injector lag at all ?

d. Once is with the right % setting an lag, would the existing fuel map for lower down the boost range be there or there abouts ?. Or am I going to have to adjust the entire fuel map again, rather than map just for the higher boost ?

Yes I could just get a pro to do it, but for me the fun is doing it myself. Just need a little help and friendly advice to point me in the right direction.

Thanks in advance.
Rob

cewrx7r1

iTrader: (2)

First you need to learn how to search as this has been discussed many times on this and other forums such as the FD and single turbo forums.

A. Best place to buy in the UK or accross the wate, or any one got some good second hand ones?

Depends if you want the stock 850s enlarged to 1200 or to buy new 1200 and what is available in the UK. Easy to have the 850 enlarged to 1200 because they fit . RC Engineering here in the USA can bores them out to 1200. That's what I ran.

B. Are they a straight replacement for the 850's and NO machining needed to rail ?

Depends on the answer to A. Stock are side feed, most others are top feed. For top feed, best to get an aftermarket rail.

c. For say 1200cc's where abouts do my settings need to be on the PFC ?. am I right in thinking 64% and do I need to adjust the injector lag at all ?

It is evident that you did not read or understand the PFC manual. Go back and reread the section about setting up the injectors. Larger injectors have a larger lag value.

d. Once is with the right % setting an lag, would the existing fuel map for lower down the boost range be there or there abouts ?. Or am I going to have to adjust the entire fuel map again, rather than map just for the higher boost ?

Your first questions does not make any sense to me.The PFC does try to equalize the new setting to the previous settings, but it will be off some. You should check your AFRs again for the area of the map where the secondary injectors will be used. Cruise above 90mph and all areas above P row 9.

e. Yes I could just get a pro to do it, but for me the fun is doing it myself. Just need a little help and friendly advice to point me in the right direction.

You need to do more research than just taking the easy way out by asking.

RobEvo5

Whilst I appreciate what help and reply you have given.......... FFS

I done a search on "1200 secondaries" and tralled through 4 pages of threads of which did not give the answers I was looking for.

You have popped up on several occassions during these threads with a similar retorical reply like 'do some homework' and read first.

I have done nothing but read thread after thread, and perhaps I could spend a little more time reading the manual as well. But its not the best manual in the world and would much sooner seek the advice of someone with first hand knowledge, and YES perhaps I have been a little lazy as well. But why spend hour upon hour reading when someone might be able to post the answers quickly for me. Like I say its not like I have not tried at all.

Anything is possible if you research and read enough. I dare say I could build a rocket ship if I spent the rest of my life reading books and searching forums. But you have to draw a line before you ask for HELP, which is all I have done.

You appear to be another pro tuner that wants to safe guard all his secrets and make people want to go to a pro-mapper. I appreciate you need to make a living, but come on.! I could be wrong but It would appear you do not like the idea of people having a go themself. Forums are meant to be an open forum for free and friendly advice.

All this said you didn't need to post anything at all and could just have posted "do some research...", and in fairness you have give some valuable info, and thank you for this...

rynberg

You couldn't be more wrong.....Chuck is just a "civilian" and has done more to figure out tuning and the PFC than anyone else on the board (well, Kyle too). He has done it ALL himself.

Bored out secondaries (1200-1300cc) will drop right in. The PFC manual tells you what percentage to enter for this size change. If you have RC Engineering bore out the injectors, they will give you the new lag time.

As far as anything else, Chuck answered your question....you will have to check AFRs under secondary operation to make sure everything is still ok....

RobEvo5

The PFC gives an equation, to figure this out and if this correct and good then fine I will use it. But if I recall this was only a guideline, and would have welcome some first hand experience on a specific injector. For ease of fitment I would be tempted with a bored out RC injector.


Maybe I have got him wrong and he don't map for a part time living (not that I have a problem with this, its just what appeared to be a little safeguarded response that pushed my button) - If I have I have probably shot myself in the foot

Fe*k it as this rate I will go against what I HAVE read in here and will just push the injector duty into the 90's to get my target boost. I have had many a non RX7 car mapped with the injectors on the near limits and successfully run them for long periods of time with no problems at all, along with knowing many other people that have done the same. If it goes POP, you can all say I told you so.

cewrx7r1

iTrader: (2)

A: The PFC gives an equation, to figure this out and if this correct and good then fine I will use it.

The PFC % change only applies to the primary injectors which you are not changing, that is why I said that you did not read or understand what you are reading.

B: Within the many threads about larger secondary injectors, side feed and top feed are mentioned many times. The discussions only mentions drilling/modding the stock injector hole when putting larger injectors into the primary positions which you are not doing.

All the 1600 secondary threads mentioned using other rails because the 1600 are top feeds. There never were any stock 1200/1300 injectors that are side feed for the RX7.

With a proper fuel system, 550/1200 are good for about a safe 390 whp.

If you searched and read all the threads on this PFC forum that I have started, you would know a lot about tuning the PFC. Then there are the many that I also contributed to.

Did you do this instead of just complain about me?

sdminus

Use pip ( wgt ) he will do you an exchange rail and can clean the injectors and test them for you.

Scott

RobEvo5

Fair enough but could swear the PFC lets you adjust the % of the injector for both primary and secondary. I have currently set primary 95% and secondary to 95% in order to lean my entire map rather than change all fuel cells. Might be a slighty unothordox way of doing things but without a datalogit and only a wideband was the quickest way of achieving the same result.

I specifically mentioned 1200cc as i thought there were some off the shelf replacement direct fit injectors. I now appreciate what you say re-topfeed/side feed and need or no need for rail on secondaries. But despite what you might think its not that clear or evident from the threads I have read.

Perfect with my stock twins running non sequential I am only looking at maxing them out and in reality probably targeting about 350rwhp. Its a shame the stock injectors are running just short of what I think the twins a capable of producing.

I don't profess to be an expert, I have owned the RX7 for about 2 months now, and considering the time I have had it, thought I was doing quite well. Sorry haven't got time to read all 3000+ of your threads as much as i would like to try, unfortunately the ones I did read seemed to have a common theme. Perhaps I have missjudged - my apologies.

APEXL8T

Thanks...now that is something I did not know or have read.
I bought my primaries from Judge Ito that were done by RC. I am close now but it may help some.