i have a few mods done to my car downpipe, intake, midpipe, bov and i think i have a fuel prob. the first indication was when i was driving i did a 2nd gear pull and it pulled hard as hell until about 4500 then it kinda just "chilled out" like i was losing power.anyway ive checke how many miles im getting and im getting 14 to the gallon. is this right?

 

you need to invest in an upgraded ecu since you have a downpipe and midpipe. I would get a Power FC and get it tuned.

 

Around the city, 13-16mpg is about the norm. You'll really only increase your MPG by adding in more highway miles.

As far as the other problem, unless you have a boost gauge it's going to be impossible to tell you exactly what the problem is... However, by your list of mods and description of the event you may be running into FUEL CUT by the stock ECU.

 

yeah im getting my friends apexi power a/f controller for free..im kinda his mechanic. i installed a single turbo into his supra a while back and he owes me. and i have a boost gauge and it reads a strong 11lbs..

 

You could be running into fuel cut, which is probably what is happening if you are on the stock ECU.

What is your boost pattern?

http://www.scuderiaciriani.com/rx7/boost_test.html

 

I usually get between 13 and 18 in the city depending on my foot, and about 24-26 on the interstate depending on my cruise speed. Who would have guessed that obeying the speed limit would save me gas money?!?!?

 

my dad drove my car for a week in all city, and got 19.7 MPG.....i drove it the next week and got 11. It makes me wonder...

 

i have about the same mods as you and getting a bit around 14. but i do get on it ever so often while keeping in mind tryinig to save gas. however, my car does not pull hard until it is over 4500rpm in 2nd. you probably have a boost leak or bad solenoid. if your boost gauge is reading 11 thats not normal. you need to do the boost pattern check like mahjik says, it should be done in 3rd gear. your car will probably spike to 12 or 14 pounds though when the second turbo comes on.

 

I can't convert liters/100km to mpg, but my Rex consumes 13L per 100km - consumption dropped from 14.5 to 13 with Stage3 ECU

I'm happy.

 

Avg of about 18-19 for me, but I'm not a total leadfoot around town. At the track it goes down a bit further...probably about 13-14, but not too severe. I'm not modded very far though, so that might be why.

 

I only get about 12 miles to the gallon.

 

'Bout 15-18.

I once got about 9 at thunderhill. The inside of my stock exhaust was completely heat-blown white.

 

At the track I get about 25-30 liters / 100km.

 

I took a road trip and got 24 mpg!!
415 to the tank.

no boost and stayed around 80-85mph.

On boost, I get about 13mpg and 225-250 miles to the tank.

 

7mpg

 

Unless we are on fire when we get 0 miles per tankfull.

Learn not to burn----see my red font sig

 

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I took a road trip and got 24 mpg!!
415 to the tank.

no boost and stayed around 80-85mph.

On boost, I get about 13mpg and 225-250 miles to the tank.
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At what point do the Turbo's kick in?

 

The turbos kick in when your foot hits the floor. They are basically "in demand". If you don't hit the accelerator hard, you can take the car through the rpms without getting into boost.

 

Thanks Mahjik - my next question is logical. When the foot hits the floor, at what RPMs do the turbo's spool up. I read about 2500 for the 1st and 4500 for the 2nd.

Is this right?

 

I get 10psi of boost at 2500rpm.

 

Spool up or hit full boost? Those are two different things. With the sequential system, you'll see full boost around 2500 rpms with the transition at 4500 rpms coming down to 8 PSI, back up to 10 PSI and then trailing to 8 PSI to redline (depending on the car and the modifications).

The only thing that is really "set in stone" is the transition area for the secondary turbo.

Non-sequential will see full boost around 4000 rpms.

 

Last trip to the coast I got 9.5 l/100 km on one tank. Amazing! I usually get 10-11 at "reaonable" speeds. If I push it well over 120 km/hr it can drop to 11-12. Still not too bad.

While on cruise I often study the boost gauge and wonder what portion of the intake "pressure" is affected by the turbos. I suspect that even with -ve pressure they do something (would be more -ve without them). I suppose to satisfy the purists, however, we will have to assume we are not using them unless we have +ve pressure.

 

hmmm today I drove about 95 miles and burned about 4.2 gallons.