Rx7 Club 2nd Gen Great! But 1 Thing
 

I think this club is great. Heck it saved me $811 when I was about the dump $$$ to Mazda for a new OMP and was told by Rx7Club members to just premix. My 7 rides even better!

However, I did like I was told and search the forums, read, visited the HOW TO web sites etc. I decided to go with the following modifications:
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720 CC secondaries
Hi-Flow Fuel Pump 255
K&N CONE air intake
No cats, straight pipe (OMP disabled, premixing)
Performance Mufflers (dual)
Stock Turbo
HKS Ground Wires
FCD
Either a S-AFC or FCON.
Boost Gauge
AFC GAUGE
Blitz Turbo Boost Controller
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But now I have another dilema! Apparently when you install bigger Secondary Injectors the car must be DYNO-TUNED with the S-AFC. GREAT! gee thanks for telling me now. I reside in MASS have no idea where to get a dyno done. Anyone?

Last, not blaming anyone. I have myself to blame. But I really would appreciate if someone "who knows what they are talking about" could lend a hand here.

I'm thinking about selling everything and just restoring my 88 Rx7 10th Anniv.Ed. New 550CC injectors, hi-flow fuel pump and perhaps a rebuild the turbo. If I do, can I keep the BOOST CONTROLLER? BOOST GAUGE? (since running no cats) K&N CONE AIR INTAKE?

OR... can I keep the mods, install and not need a dyno?

anyone? If you help, you :rock:

What if I install a hi-flow cat or resonator? (removing the straight pipe) Will that be alright if pre-mixing?

Get new 550CC injectors, bigger fuel pump and K&N air intake? + keep perhaps the boost controller and turbo timer. Will that be safe, yet produce some more HP?

Your AFR gauge should help you set the S-AFC.
It takes longer without a wideband, but it works.

Your AFR gauge should help you set the S-AFC.
It takes longer without a wideband, but it works.
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The AF (air fuel curve gauge) can set the S-AFC? Huh? I dont think I follow. Are you saying its safe with the original mods?

as long as its properly tuned and not leaned out.

& to get it properly tuned it must go on the dyno, right? most place that run a dyno can install and properly tune the S-AFC correct?

wrong, you dont need a dyno, but you do need someone to help you with it that has experence if you can find someone, otherwise read alot.

I found a place that will dyno-tune. I'm just going there to get it done and get it done right

JTM, if you havent gone to the dyno yet i would definitely recommend the place I went to in fall river. im trying to remember their name off the top ofmy head but it was $50 for an hour of wideband and that was an hour from the first pull. guy was great and i plan on going back.

If you think of the name, let me know. The place I am going to is in HANOVER, MASS and they charge $150 per hour. UGH. I was just told that 720cc injectors + hi-flow fuel pump and AFC wont do shit for performance, since I am running a stock turbo. That I am wasting time and money. Anyone know if I install the K&N Cone filter if I will be ok? To much air? dunno

The upgraded fuel system will definitely help, since it will let you turn up the boost safely, but you'll need a Fuel cut defencer. PM jimmyv13, he sells em for cheap. If you upgrade your turbo, you should go with a standalone anyways.

I got the FCD. So, I should stick to the 720cc secondaries, hi-flow fuel pump and the S-AFC - Then get it dyno-tuned and be ok? Remember, I am running stock turbo - no intention to upgrade turbo just yet

Anyone? This all sounds correct to me... Keep the stock 550CC's, K&N Air intake, Boost Controller...
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And stock injectors, with more pressure dialed in using the adj. fuel regulator, will handle that pressure just fine.

Adding a K&N filter, will let in a little bit more air,
but not so much that you would need bigger injectors, let alone giant 720s
If you put 720s on that engine, it won't run, it will drown !!

I guess you spend a lot of time on forums, listening to chat-room charlies, and forum fredies.
95% of the info from these sites is pure crap !!
Half those idiots have to ask how to put in new plugs..................
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Wow, that made sense. :) I mean honestly, the above is 100% ACCURATE???? 720CC will drown my motor?

Drop in cone filters never do much. Terbowetoo is right, you just upgrade your fuel system (ie: bigger injectors and fuel pump) so you can safely raise the boost. That is where you will see better performance. (more hp)

Tim

If you put 720s on that engine, it won't run, it will drown !!
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This is what i am told by a guy who has modified his Rx7 (street ported + T4 turbo)
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Upgrading the secondaries 720cc will drown the engine @ stock boost levels.

thats why theyre telling you if you do upgrade the injectors and pump that you can safely run higher boost levels. just read what theyre saying and stop second guessing.:D

OK well 720's are good if you have an SAFC to retard the pulse time and are running over 10psi.

10psi is the general thought of where the stock injectors tend to max out(the 550's).

Getting an SAFC and keeping the 720's would be the best if you run somewhat high boost levels and are going to dyno it to get your A/F ratio set.

I have heard that the stock turbo starts to die/lose power around 12-14psi.

alos quoted from above
"Upgrading the secondaries 720cc will drown the engine @ stock boost levels" That's true because stock levels are arounf 5-8 psi(depending opn S4/5) and the 550's take care of it fine because it is STOCK levels.

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Pretty much with your mods I'm guessing your over/at 10psi. 720's are a good safety precaution and without an SAFC it will give you less gas mileage. I know J-Rat has 720's on his. You might want to ask him for some semi good settings for the SAFC.

Also the secondaries come on at like 3-4k so you getting into some good boost by then and before those rpms the 550's should be doing fine.

Ok, it looks like you have the same decision to make as I do. You can:

1. keep you car boosting at stock levels (or at least close to stock levels) and get a F-CON and have the bigger fuel pump.

or

2. get the 720's with the S-AFC2 along with the bigger fuel pump and raise the boost.

*option 1 would not give you more power but it would keep your car reliable and you would not have to worry about it blowing up.*

**option 2 would give you more power b/c you could raise the boost, BUT, you would HAVE TO find a place to get the car dyno tuned properly. And it sounds to me that you would have to find a professional to do it for you.**

Tim

I'm not second guessing- just mix opinions, but now this is starting to make some sense. Okay, so I run 720's + DYNO-TUNE the S-AFC with the BIGGER fuel pump - I'll be okay?

Yup. You would be fine and should never have to worry about detonating.

It's all about getting the AF ratios set and done so you don't have to worry that your richening in one area while your leaning at a certain rpm.

I am doing a TII conversion and will have a 2.5 DP to the Corksport 3inch with a TID and expect to be able to barely squeek by without getting bigger injectors.
I will be getting a walbro though.

If you dyno tune the car with the 720's then you'll be set for a while since you won't be maxing out your injectors. This will also be good if you get a better turbo down the line.

Something to keep in mind, if you're running straight pipes (no cats), you're automatically going to get more boost. So.. at stock boost levels, no probably not a need for more fuel, but as you turn up the boost, either on purpose (with a boost controller) or by "symptom" of a free-er flowing exhaust, you would probably need more fuel (and the addition of the FCD). Honestly, I can't tell you where that point is, more experienced folks on here will have to say.

But just keep a couple things in mind:
Free-flowing exhaust=more boost
more boost=need for more fuel
need for more fuel=need to control it (SAFC, standalone, FCD, etc)
need to control it = more $$$ :D

Hey Tim, pm me if you're ever interested in the F-CON. I still have it sitting in my room. We can meet some where for you to pick it up :)

hey wuts up. I'll have to get back to you on that later, I still have to make up my mind. Thanks though.

Tim

720s
 

Okay.... Not too sure where to start here.

YES, I do run 720s in my secondary positions.

WHY? Because of my mods, I boost creep so bad that I usuall hit 14-15 PSI. Is that GOOD? No, its a stop-gap measure to prevent knock. Dyno tuning would help the original poster here, but you can get along without it, but it really depends on boost levels. I run a 0% correction with 720s in the secondaries. That is WAAAAAYY too much fuel...:D I think Scott89T2 said that -13% at around 10 PSI was a good all around setting (this would be ABOVE 3800!!!!)..

AND, whoever told you that modding on the stock turbo wont net you performance gains is full of shit... I think that the stock turbo can push an 10th AE into the 13s, and I intend to prove that point.

Point is, you can tune by the "seat of your pants" and use your AFR as a GUIDE. But nothing takes the place of a good old dyno.

Run your corrections on this basic premise. The stock fueling was good to 10 PSI. Anything above that, and start adding corrections to the 720s. But start them at say.... -8 to 10 % correction, and work up from there. DONT FORGET, this is ABOVE 3800!

Jarrett (mods in my sig)

as j-rat said, a decent afr meter will help you tune alot, but you will also need an EGT. they are more accurate than a afr gauge and help you tune better.