mazdaspeed7

If you dont want to attract unnecessary attention, true dual isnt for you. The gains over a good single exhaust are minimal, lke 5 or so hp, maybe 10 depending on mods, but it is SO much louder. If you want more hp with a semi-quiet street exhaust, get a single outlet header and a silenced midpipe. RB muflers are about the quietest aftermarket mufflers of good quality, and they are still too loud for most people with the true dual, and thats with a pair of silencers too. Ill post more later, I have to go do something.

mazdaspeed7

I got the injectors b/c I was running so lean power would fall off at 6K rpm. The general consensus among n/a owners is that the 550 CC secondaries help a lot after you have full exhaust and intake. The TII fuel pump flows better and works better at higher fuel pressures than the n/a pump.

I am still running lean, but not so bad now. My car pulls hard to 8500, no hesitation, but my plugs are always light tan to white, and only last about 8K miles a set.

mazdaspeed7

My exhaust is custom, with the RB dual outlet headers. Im getting Supertrapp mufflers soon.

90 GTU

You can keep the p/s and a/c if you want, but thats about 80 lbs worth of crap, and youll lose hp from the extra belts/accessories. And the steering feel on a p/s rack without the pump is awesome. Its even better than with the pump. And parking lots arent bad at all.

Audiofight

Alright.

Time for me to post back in my thread again.

This coming week I will perform the TB mod mentioned earlier. A friend of mine, who used to own a 1st he dragged, is intrigued to help me out as well. So, the two of us shouldn't screw up too much stuff. If it doesn't look important, it will get taken off.

All the smog stuff is also going. Time to plug up that stuff and lose the weight.

I think the single exhaust will be my choice because I get enough attention as it is with my car and I don't feel like putting up with more po-po problems.

I am really glad to see the amount of information flowing through here. Some stuff I didn't know and other stuff I had considered.

How much work is involved in replacing the fuel pump? Is it nearly as bad as on some domestic vehicles? My dad's truck, in tank as well, was a project and a half because we had to drop the entire tank out which involved removing half the exhaust and other cables before it would clear.

mazdaspeed7

The fuel pump is very easy to replace. Pull up the carpet in the hatch, and find the alum panel with a plug and wires going through it. Take the screws off and move the piece out of the way. You will see an oval panel screwed onto the top of the gas tank. Unscrew all fo the screws and pull it off. The fuel pump is mounted on that. Its a little tricky to get out because the fuel lever sender, but once you look at it, it should be pretty obvious how to get it out.

Audiofight

I am glad to hear it is easy. Hopefully I won't have to dig into it yet. But I'm sure that I will eventually. Never get enough power unless I drop a 20B into this contraption

I will probably replace the fuel pump in the later stages of modding. The cold air box and intake/exhaust work is going to be first.

Exhaust is necessary due to one muffler being plugged and the cats being non-existant. First two are missing and replaced with pipe while last one is gutted, by me earlier this summer once it plugged up.

RB single header and RB mufflers will probably suffice with a hi-flow presilencer or no presilencer at all. Not sure yet.

RarestRX

Yo,


Okay, here's my Q:


Will putting in a TII pump and injectors help out a mildly modded NA RX-7?

I've got an intake, RB downpipe/silencer and HKS 50mm exhaust. Still running AC, air pump, etc.

Thanks!

KS
1989 GTUs "More fuel = mo' bettah!"

Poindexter10thae

iTrader: (2)

ok, couldnt resist any more.

You can go about getting the most out of a N/A 1of 2 ways

1. Stick with stock fuel injection(which looks to be what you are gonna do)
2. Carburetor conversion(good for 40-50 HP out of the box)

I have done the carb conversion to my 86 SE and love it, I do have 1 power adder though, NOS. And Ive heard a rumor that Holley is making a special new upper manifold for the 13b 6port that should improve flow and give about 10-15 Horse increase over the current setup.


-----------------------
86 SE
48mm weber sidedraft carb kit
RB header/dp/presilencer
MSD 6A
perma cool E-fan
NOS 125 shot
smog pump in a wal-mart dumpster

mazdaspeed7

I think you would be best off with one or the other. The injectors would be nice, but you could get just as much, if not more fuel from a TII pump and FPR, with raised fuel pressure.

pp13bnos

iTrader: (1)

Its my opinion, that the stock 89+ injectors are good for just about anything you need to do. If you are leaning out at high rpms....i bet is either the pump, or the fuel rails not holding the correct pressure, clogged fuel filter etc.

I'm running cleaned stock inj. on my car that has the following
Street port
Full RB exuast system
ported middle, upper intake and TB
Cone filter
Removed double throttle and coolant
Pineapple 6 port sleeves
T2 fuel pump
Jacobs ignition wiring
Ported black elbo

Under full throttle in any gear (Never redlined it in 5th!) i'm reading 2 bars green, and one yellow. Now i should be pretty easly over 200hp, according to Rob@Pineapple

So, instead of putting bigger inj in your guys cars. Spend that money on getting your injectors cleaned. Not only will you make more power, but get better milage too.

BigWookie, just putting on a carb over the stock inj is'nt worth 40-50hp. I beleive RB said it was good for 35-40 with a full exuast, on a 86-88 n/a Rx-7. Not the 89+, witch came with 20+ more hp over the 86s.

CJ

CJ

Node

iTrader: (1)

fuel pump swap from scotts site i think
http://www.1300cc.com/howto/how2/fdpump.htm
they also have a dual pump rewire how-to
http://www.1300cc.com/howto/how2/rewire.htm

enjoy

Node

iTrader: (1)

Would upgrading to a FD or Cosmo fuel pump while your at it be of any use?
Or is that more fuel than youd ever need, or would you have to upgrade in stages???

Audiofight

If I can seriously get that much more power w/ a carb upgrade and full exhaust system (which I plan to do).........

Then how much more power, if any possible, can I get out of a modded FI system?

Which will be better in the long run? Fuel Injection w/ mods or all-out carb setup? I want more power, but I don't want to go so far that the car isn't feasably driveable for long trips due to sacrificed gas mileage. I get around 20-21 mpg right now and would like to stay as close to that as possible.

I don't really care if my RX doesn't hit 200+ HP, nor do I care whether it is in the 13s or not. If I run a high 14 and am keeping 17-19 mpg, then I will be extremely happy.

Where can I buy the carb setups reasonable? What is recommended as reliable? Which ones actually work?

RarestRX

Yo,


Thanks Mazdaspeed! Hey, so I've got another couple of Q's:


Can I take out my fuel injectors without taking off the intake manifold? I'd like to send them off to RC Engineering for a little love.

Which Fuel Pressure Regulator do you recommend? Do I really need one for my NA 13B?

I just need to get a TII fuel pump right? Not a Cosmo pump, 'cause that's for the big turbo stuff, right? I remember RETed was always telling people to rewire their fuel pumps 'cause the wiring going to the pump is crap. Have ya done that?

Thanks!

KS
1989 GTUs "Mo' powahhh!"

Ryde _Or_Die

Well my car is not running right now but have a question that pertains to what you guys been talking about here...if anyone has the S-AFC on their NA let me know. Can you just get the A'pexi S-AFC and be fine? Or would you still need the TII fuel pump &/or injectors? I am defintely going to end up getting it for precautious reasons at least, just wanted to know. Thanks.

Poindexter10thae

iTrader: (2)

Carb setup= www.mazdaracing.com
It aint that bad on gas mileage, but then again, i dont really pay attention to it all
To clarify= the carb setup alone will yeild approx 40-50 more horses straight out of the box.

And if you go with a true dual system exhuast(you HAVE to have a free flowing exhaust with a carb setup) it should yield an additional 30 horses(as mentioned previously)

And dont ever rule out puttin a N/A on some juice! they love it!

Node

iTrader: (1)

reminds me of muscle cars since we've gotten into carbs, where are the shaker hoods and cowls?
lol
could you take a Turbo II hood and make it into ram air? be some pipework to do but think that would help at all
so 40-50+30hp w/ true dual and carbs....uhm 70-80hp+160hp on an N/A
thats one badass N/A rotary, kick out 230HP. What else can grab some easy horsies, and how much do carbs cost?

FPrep2ndGenRX7

Node - they mean its possible to get 40 HP over stock if you also have a true dual exhaust. You can't just add the HP figures together. The parts all work together to get some of those figures. Indivually they are good but not as good.

Mazdaspeed7 - Did you ever make any dyno runs to verify your 230 HP stock port engine? Just curious. I'm using a stock port engine in my FPrep car and was curious what I might actually be capable of.

TurboII RudeBoy

Throw a tbone in the hatch or a sirloin under the hood

mazdaspeed7

I havent got my car on a dyno yet, but I plan on doing it before Christmas.


Carbs. If you want even decent gas mileage, stay F.I. Carbs get horrendous gas mileage once the hp starts going up. A 220 BHP carbed n/a 13B(typical streetport/intake/full exhaust) will get you 8-12 MPG. A F.I. engine making the same power should be getting over 20 mpg. I get between 22 and 25 in my car.

mazdaspeed7

The hood on the TII hood is in a low pressure area. The scoop does next to nothing, and brings ibn a minimal amount of air. Evil Aviator has a graphic of the pressure areas on an FC, but I dont have it saved on the computer I'm on now.

I would stay away from carbs. They are much less drivable than a F.I. engine. You want easy horses, look at my mod list. Almost everything on there costed me next to nothing, if anything. Much of it is free HP.

I forgot something else I had done to my car. I cut the crush washers off the spark plugs. This moves the spark a little closer to the chamber, and raises the compression slightly. I have a 90 block torn down at my house, and I checked the clearances on one of the rotor housings. There is still plenty of room.

kliftin

I have a s-afc and just got the wiring diagram today. Im going to install it right now. Im going to dynamic auto sports this monday to tune and dyno it. I will give you my readings. I have the same mods as mazdaspeed7 except the intake porting and I took the msd back. I will get it agian soon.

What I know about the afc is it will work great for an fc without injectors or pump. I have an n/a and am running rich so tunning is still important. An afc will let your stock injectors work harder than the computer will allow so pump and injectors is unnecessary althou if your runnng over 60 percent static or so I heard they will wear out faster. But your not always racing so whatever.

Ryde _Or_Die

Alright let us know mane.

fuzzi

Hiya... i dont know much about injectors... are the stock 86 injectors able to handle the extra fuel pressure, that would be given from a T2 Fuel Pump, or would you have to replace the injectors ?? ... My buddy has a t2 fuel pump sitting around.. so im wondering if its beneficial....P.s. My engine has a street port and headers, and K&N filter...would these make it run leaner ?

wankelhead

hey cj
your not using a s-afc to control fuel...right?does your car run rich at idle with the t2 fuel pump?
d