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devil280Z

1jz in a Z, gas mileage.

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Hey guys, I got into an argument with a co-worker about gas mileage the other day.  I told him with a 1j vvti In a light 240 body I could easily get high 20's for MPG.  He swears that ill be lucky to get 22 MPG.  So this brings me to my question, what gas mileage are you guys getting with your swaps? Driving conservatively or even like a bat outta hell..... Let me know so I can win some money off this guy! lol

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I have a non vvti. I don't drive it hard all the time but it really doesn't matter if I do. I have HKS 272/264 cams 550 injectors and stinger standalone and a PT61 turbo. 446hp@16 psi

 

 

When it was some what stock I never got over 18mpg. That's with the PT61 turbo and stock 440 injectors and the stock ecu and a apex I neo

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I have found with the OEM JZ engine if you stay out of boost you can get low 20s in fat supras, so I would imagine if you stay out of boost in a Z mid 20s should be attainable. However you don't swap in a 300+hp monster to drive like a grandma ;).

Edited by ask92

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If you aim to set it up for it, you could hit 25.  I wouldn't romp on it at all on that sort of tune, but if you head into the project with the right design (I'm running VEMS, it'll allow on-the-fly tune switching), I don't see why you couldn't hit mid 20s without much issue, and you could probably hit low 30s, depending on how close to the wire you want to play it.

 

The s30 weighs like a thousand pounds less than the mkiii supra, IIRC.

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I have driven my 7M powered Z to Vegas 3+ times and SoCal 4+ times to the MSA west coast nationals and vacations, and have gotten 27~28 mpg when I kept my foot out of it and left the A/C on. I used a GPS to get accurate mileage as I have a 3.73, CLSD, and checked it via the pump for actual gallons, on the trips to and from. But if I abuse it, I can get it down to 15~17 mpg.

Edited by ARZ_

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Some of these gas mileage numbers have to be way off. The numbers you guys are throwing out are worse than. I get in my Supras, which weigh literally half s ton more. My 7M cars averaged 10-20 driving hard, 24-26 on the interstate typically. Current 1J car averaged 22, all city driving. 10.0-10.5 AFR everywhere in a full weight MK3 Supra. 6262/440cc injectors. I have seen several 1J Supras with standalones hugging close to 30MPG with conservative driving, I would think Zs could best that.

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10.5 afr's? Thats just about not possible. That makes me instantly not give a crap about anything else you say.

 

He's talking about his air-fuel ratio.

He means he's running a 10.5:1 ratio of air and fuel.

10.5 is a little on the rich side, but not by much. I think target is 11-12 cruising, 15 engine braking, and 10-10.5 when accelerating.

This is for the 7M, and I draw the numbers from memory. I might be wrong.

 

Anyways, got a buddy with an MA70 with a 60:1 CT26 (Up to 14psi).

He's running lean, but not dangerously so. After he fixes his BHG (Which made it to 197k miles with the stock headgasket), he'll install the 550cc injectors and Lexus V8 MAF, straight pipe and downpipe. Then he'll need a new clutch because his stock one will have slipped itself to powder, and then maybe a fuel computer.

Right now, with just the 60:1, he gets 23mpg driving normally now that he fixed his knock sensor and vacuum leak. ~6-8psi per gear when accelerating, 4.5k shift points, with the occasional 14psi, 6.5k pull.

In a car 1300lbs lighter (Including his stereo equipment), the mileage should be easily in the high 20's. 27mpg practically, but capable of 30mpg if driven stressfully calm.

 

BUT this requires the engine running correctly. Willing to bet that Pat1 has some sensor messed up that's making it run rich, or his driving habits are rough for a daily.

The knock sensor is pretty much always out on the MA70. No idea about the JZA70, but stands to reason. Other than that, if he's running larger than 550cc injectors (Again, based on 7M stats) with a stock ECU, it doesn't know what to do with it and just dumps fuel all the time.

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Your air fuel ratios are way out. 10.5 is rich as hell. That's just will make your eye water standing behind it. Lol 14.7-15.1 cruising fuel Econ. Accel 11.5-12.3 that's in the boost.

 

I'm running standalone no wires are crossed lol. I'm on the gas a lot and that why it's getting bad mileage. But I don't care I didn't build it to get good fuel mileage. I build it to beat the hell out if it. I've been tuning it a little lately. I'll see what I can get out of a tank and report back.

 

446hp @16 psi on a stock bottom end 1jz is running pretty good. I promise that there are no crossed wires.... Lol

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Pretty much the only time it went north of 10.5 was at idle, right around 11.0. Idk maybe my brand new AEM wb reading is off but smell/plugs back it up. Car had JDM 2J 440s with a stock fpr, no tuning whatsoever on a JZA70 ECU. Distance/gas used from fill up to fill up put it right at 22.4 MPG. Was breaking in my clutch so pretty much zero boost.

 

Unfortunately, my very first pull grenaded that R154 and I haven't driven it since so can't say how much worse it'd be with decent weather/ aggressive driving.

Edited by Quin

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my buddy has two VVT-I 1j swapped cressida's that he daily drives and says he gets pretty good mileage if he stays out of boost. I don't have any specific numbers but he usually only puts $10 on 93 octane at the pump and it usually lasts him about half a day and thats with occasional pulls and drifting. So if you can resist getting into the good part of you JZ engine you should be good.

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I get great mileage from my 1j.

 

I've been running the car on the road for over 3 years now and keep squeezing more power from it but the mpg doesn't seam to change. I get about 32mpg on a run if I keep the speed below 80mph. I drive to spa every year (330 miles) and get there on a tank without a problem. Car weights 1284kg and make 392hp at the fly with the only mod being cams. Standard ecu, injectors, and turbos. I've also run a few 11.2's @ 131mph with a little shot of nos. these engines are superb on fuel if you don't mess around with them too much.

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