Spoolerr

I am going to run a bit of an experiment by running the Probe GT 330 injectors in my FC, just the two primaries (87 TII that uses high impedence injectors)

My FC is getting about 15 mpg and its in very good running shape. i have tried everything to get it to see some more fuel mileage but nothing works


So i am tryign smaller injectors, i wont be boosting it at all tho

i cant afford to drive her anymore
brandon

FC3S.USD

iTrader: (2)

what fuel do you use ? 91 ? If your just concerned about fuel economy and you dont want to boost. Trade your T2 for a NA plus some cash, then put some $$ into na for fun. But not gas consuming.

Spoolerr

I have owned many turbo cars including a 13 sec dodge caravan and an 89 probe GT that went 12.8 on a custom SDS standalone, with custom manifold and .60/63T3 pushing 28 psi on stock internals. The rx7 i got cheap and dont have any intention to get rid of it, however, personally i think under light throttle and cruise my motor should hold together, i am just trying it to see what will happen, i'll post results.

Madrx7racer

i personally think you're wasting a good running 7 if you can't enjoy it..............you can cruise the same in a honda that gets u 30 mpg

BLUE TII

iTrader: (9)

If you ditch the catylitic converters then you can run your TII VERY lean in cruise to save gas. When you get it too lean it will surge at constant throttle- richen it up a bit from there.

I'm sure you can think of a better way to lean it out than going to smaller injectors!

How about a cheap used Safc set-up to just remove fuel at very light throttle (set up off TPS or manifold pressure sensor).

RotaryEvolution

iTrader: (30)

also....


you are still in boost below 0psi, most people just don't realize the compressor is doing work. running that small of an injector you are very likely to pop the motor even driving it mildly.

my suggestion is to open up the exhaust and add a way such as an SAFC2 to lean out the mixture during cruise to conserve gas while leaving the upper end rich while in boost. you can pick up an SAFC2 for about $150 used which it would pay for itself in under a year of gas savings.

the car will run like *** with those injectors anyways.

Spoolerr

very true. I just cant stand the less than 15mpg any more, and it is cool here in canada soon to be cold, i dont have much problems with detonation usally during the winter, seems to keep the motor cool but who knows

i will mess around with the 550s more first i guess.

dcrews

iTrader: (2)

dude, if you put in those injectors, and don't do any computer programming, you WILL blow it up. Period.

The computer expects to see 550CC injectors, and injects the fuel accordingly. If you put 330cc or whatever they are, the computer isn't going to inject as much fuel..


the 330's are 40% smaller than the 550s... if you're injecting 40% less fuel, guess what?

You go lean.

You go boom.

What a waste of a TII.

Go buy a Honduh

WonkoTheSane

iTrader: (2)

Guys, lay off him a bit.. He just had a good idea that he didn't think all the way thouigh, on how to keep ahold of the 7 that he loves. I'm sure if he wantd a honda, he'd own a honda now.

I think the sAFC, and gutted/removed cat will yield the best MPG upgrade for your buck. Don't mess around with the injectors unless you have a way to control it.

RotaryEvolution

iTrader: (30)

even an SAFC is not really necessary, a stock engine with open exhaust should run right around 20MPG if it is running properly, i get between 18 and 20(24-25 if i baby it and lean it out)with my T2, the SAFC settings are all in the + range and i have a bit of a lead foot at times.

set the timing, do a tune up, check compression, set the TPS, be sure your grounding is all nice and clean, check sensor readings at the ECU to be sure they are reading properly and there is no problems with the wiring or sensors and if everything is good then you should see those numbers.

i also run 87 octane, however you better be damn sure your engine is running the way it should if you try that.. if you keep the engine out of boost then running lower octane in a turbo is fine.

NZConvertible

He did not have a good idea, he had a truely retarded idea. Anybody who thinks reducing the amount of fuel the engine is getting most of the time by 40% is a good idea should not be modifying cars. I doubt it would even run. The obvious lack of EFI knowledge is startling...

RETed

Please get rid of the car and sell it to someone who really appreciates it.
If you can't afford to drive, then don't.

Please don't apply such insane logic to try and get more mileage out of it.


-Ted

Spoolerr

i am not some punk *** kid who's parents bought me a TII, and now i am dicking with in without asking first atleast

Well, you can think what you like. I love my tII I pulled it out of an auto wreckers five months ago with a bad engine, no lock cylinders and a very messed up dash because the car had been stolen and dumped (joy ride i guess). I pulled it out and spent the last five months doing the body and just had it painted, cleaned and peiced back the interior, and before all this i had installed two engines. (The orig iengine had bad coolante seals, So that one was put aside. I ordered an S5 Jspec and cracked an apex seal because i lacked understanding of the operation of fuel injection components and used low impedence resistors with high impedence injectors. She leaned out and caboom, no compression on the rear rotor.

I pulled it, did a complete rebuild,(swapped rotor and housing) small porting and put it all back together nice and clean, got rid of the resistor packs my car had from the factory. Now everything was cool, she ran nicely. I had her to TMP and didnt do too bad, mostly a few low 14 sec passes at around 98 mph( yeah, with those traps i cant drive either). I didnt think that was too bad for mostly stock, around 7psi.

However, that was all fun and my tii was awsome during the summer, last week it was back to school. ( i'm 18, last year of hightschool). The car is getting 10ish mpg would probably be more accurate, and i was thinking of installing my SDS em-3f ( www.sdsefi.com) since i already have it and all the components. (will need the latest version of software i think)

I dont have acess to a wideband anymore, but i figured that it wasnt neccesary to have 550s as long as i kept it under 3800rpm, in very light throttle and cruise maybe i could get away with 330s since they drop right in, and use some 720s for the secondary injectors too keep a moderate balance. I just know that my car runs too rich and i cant figure out how to lean it out a bit, maybe a safc is my best bet, i guess with the stock injectors i could trick the ecu to theink they are bigger to run the engine leaner? That would be good i think...

i love my tIIs performance, but i dont really need it for the next few months and school its whats most important too me right now. If its gona cost me $30 a day to drive five minutes to school and back, there is a big problem. I definetly wont give it up either, so i thought i would try that simple drop in and see what happened with the stock ecu first. Sorry to dissapoint everyone!

but thanks for the honust opinions.
brandon

WonkoTheSane

iTrader: (2)

I'm not saying switching the injectors in a car was a good idea (which, now that I'm not tired, it does read like that ), I meant the trying to get a handle on the fuel consumption is a good idea, and if you follow the logic of carubrators, switch to a lower-sized jet, and you input less fuel. A lot of people really aren't aware of the amazing customization abilities of EFI. I'm just saying that the responses were really harsh, when a simple "You'll likely make your engine go pop, you should look into a fuel controller." would have sufficed.

No one here can tell me that don't haven't had any ideas that aren't completely thought out. A "OH NOES! SELL YOUR CAR AND BUY A HONDA" is completely overkill to someone who needs pointed in the right direction. If I didn't know what I do about EFI, then it's likely that I would think that just switching injectors would work.

Spoolerr - Seriously, just look for a fuel controller, and a wideband 02.

RETed

I didn't imply that you were, but see below...


Dude, you're still a kid.
Unless you're not living with your parents and paying for your own place, you're still a kid.

Let me give you some advice: you need to figure out who you're ******* with before you stick your foot in your mouth.


-Ted

Aaron Cake

iTrader: (1)

Please keep it friendly people. Some of those comments are right on the line, and I already deleted one that was a rules violation (big surprise who it came from as well ).

RotaryResurrection

iTrader: (8)

For one, your engine is ported. For 2, it's a recent rebuild and may not even be fully broken in yet, so compression could be on the low side still. For 3, you said you bypassed the resistors, I assume that means the fuelpump is running full voltage at all times. Though a fuelpump rewire is a necessity for a modded turbo car, it will cost you 2-3 mpg all the time.

With good compression, a good ignition system with properly set timing, fuel injectors spraying properly, no vacuum leaks and a functional 02 sensor, y ou should have no problem getting 15-20mpg out of the turbo car; I think I've gotten as much as 22 before.

I'd suggest fuel filter and pickup screen, and cleaned injectors; new plugs and wires, and a downpipe and midpipe if not already present. Check and set your ignition timing, and replace the 02 sensor, being sure a good connection is made on the engine harness side, since those wires often break.

Jack up the car and be sure all wheels spin freely with no resistance from bad brakes or wheelbearings. Properly inflate tires, and perhaps change your trans and diff fluids for good measure.

All of this, combined with a light-footed highway driver, should get you 15-22mpg.

The idea about injectors was no good. The car would probably not even idle with 330's. It would be impossible to pull out on a hill, or in traffic, if the need arose; the car would just sputter and die.

IF you were dead set on dicking around with that stuff, you can try adjusting the airflow meter spring tension, which is an old school crude a/f adjustment, or perhaps try some NA 460cc's, which would at least allow it to start and run normally, and most likely drive normally (I"ve done it).

Spoolerr

Maybe you could give me some guidance then how to get some better mileage then, rather then just posting nonsense?

Smaller primary injectors is a dumb idea. What would be a better solution? safc? how can i lean it out during idle and cruise? how can i make 20ish mpg considering that my car has no emmisions devices? it consistantly runs rich and has a very inconsistant idle however i have never been able to find any vaccume leaks even after removing and reinstalling the intake manifolds and removing the rats nest.

I dont mean to disrespect anyone, but i didnt ask whether i should sell the car, or i didnt ask your opinion on wether i deserved it. I asked for ideas around using smaller injectors.

i am definitely considering everythnig everyone said. Thanks for the advice and ideas everyone

Spoolerr

Thanks i was thinking of the 460s as well but if i can play witht he car and get 20 mpg i would be very happy. Its still got the fuel pump resistor too so thats not so much of an issue, new filter plugs wires pretty much everything. Compression is very good as well with the piston engine tester i was seeing three consistant 120 flashes on front and rear rotors. I think the engine is in good mechanical shape, runs very nice...

thanks for the advice i will start revising my car.
brandon

WonkoTheSane

iTrader: (2)

One often overlooked source of major vacuum leaks are the manifold gaskets, the one between the upper and lower, and the lower to engine. I'd check/replace that, and maybe add some RTV (or other form-a-gasket) to it when you put it back, that may help

Other than that, listen to Kevin (RotaryResurrection), He's one of those guys that when he talks, pay attention

RotaryResurrection

iTrader: (8)

^ smart man...

That's right son, never question my authoritah

Spoolerr

i will!

I'll let you know how my results turn out thanks again!

brandon

RotaryEvolution

iTrader: (30)

i thought i had some decent suggestions too... *shrug*

btw, i don't even run an O2 sensor, the wire is tied up to the a/c high side line and i see 20+mpg easily.

the O2 sensor has never been hooked up since i owned the car and it has always gotten much better gas mileage than most other seven owners i see complaining about mileage. a faulty O2 sensor can kill mileage, even a good operating one seems to run the engine a bit rich from what i can tell.

(passed emissions test without the O2 hooked up as well with flying colors)

Spoolerr

yes, i replaced the oxygen sensor with a bosch replacement, thats the first thing i did once i had built and installed the S5...... I think my tps might not be functioning properly altho it was tested about six months ago. I will restest / replace that too.

Cybaster

if u are willing to spend around 200 bucks, get a Crane Hi-6 Capacitative Discharge ignition. It got me 2 more mpg with my upgraded turbo and extra injectors. Its all around the forum and its pratically a proven fact that they save gas and also improve high-end performance.

but one advice before u install the Crane Hi-6 is that your car should be in GOOD shape and the crane 6 is adding ON to the car, not covering up any problems you are having, then that is a good investment.

other than that, unless your O2 sensor is really ***'ed up it doesn't really help if you replaced a new O2 cuz I replaced mine which was 2+ years old, and it didn't do sqat to my gas mileage....