# Gas Milage



## Xorti7 (Dec 27, 2004)

Hey, I've had my Z for a month now and lovin every time i drive it. I always look forward to driving anywhere I can just so i can drive it. The only thing I can complain about is the gas milage.

I was wondering if, with a little big of modification, i could fix this. Do things like a new cone air filter and maybe new exhuast help me out a bit? As far as everyday driving goes that is. I was thinking about doing these ne ways just to free up the extra power.

Someone was telling me I have to change all of the intake up to the turbo. I thought I just take out the resinator(optional) and bolt on a nice new cone filter and call it good? Is that true?

Any other suggestions about my Gas milage and fun mods would be nice. Thnx again.


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## asleepz (Feb 24, 2004)

Xorti7 said:


> Hey, I've had my Z for a month now and lovin every time i drive it. I always look forward to driving anywhere I can just so i can drive it. The only thing I can complain about is the gas milage.
> 
> I was wondering if, with a little big of modification, i could fix this. Do things like a new cone air filter and maybe new exhuast help me out a bit? As far as everyday driving goes that is. I was thinking about doing these ne ways just to free up the extra power.
> 
> ...



Yeah there is no FULL intake for the Z that's prefabbed, just pull out the stock airbox and replace with a 3" K&N or equivalent filter. Exhaust really isn't going to help much.

I get 24MPG at 35 33MPG at 55 and 25-28MPG at 70-80


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## Domdogg123 (Nov 12, 2004)

♣AsleepZ♣ said:


> Exhaust really isn't going to help much.


You're joking right?
and
K&N info..


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## asleepz (Feb 24, 2004)

No I'm not. At stock boost it's not going to help much. 

Show me some proof (actual proof) that it does.


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## Xorti7 (Dec 27, 2004)

Thanks, I just filled it up again and got about 20mpg for the life of the tank. Not to bad, i was expecting a lot worse judging by what the meter on the dash said. 

I just dropped her off at a shop down the road. I pointed out a small oil leak thats dripping onto a metal cover on the driver side. Prob just an old gasket, so no big deal. I mainly had them check my breaks. I'm loosing a small amount of break fluid over time and thought id have them check it out.

Im a little concerned about my turbo. It makes a small amount of a sort of rattling/grinding sound right before it passes the 0 mark on the guage. Is this just the normal sound it makes? Also under pretty heavy loads i dont feel much of a change in power and the boost meter doesnt go much past 2 or 3. (in 1000lbs/hg or whatever is the stock gauge units) Also, assuming my turbo is working right, is a turbo timer worth it?

Hopefully you guys can either assuage or confirm my fealing; either way, input would be nice. Thanks again in advance... one of these days ill get to be the knowledgable one helping out the less fortunate... instead of the other way around.


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## JAMESZ (Mar 12, 2004)

♣AsleepZ♣ said:


> No I'm not.


Whoops your wrong. The CM 3in turbo back makes good power on otherwise stock cars. I don't feel like looking up a dyno graph so I won't spout any numbers but exhaust can make decent gains.


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## JAMESZ (Mar 12, 2004)

Xorti7 said:


> I pointed out a small oil leak thats dripping onto a metal cover on the driver side. Prob just an old gasket, so no big deal. I mainly had them check my breaks. I'm loosing a small amount of break fluid over time and thought id have them check it out.
> 
> Im a little concerned about my turbo. It makes a small amount of a sort of rattling/grinding sound right before it passes the 0 mark on the guage. Is this just the normal sound it makes? Also under pretty heavy loads i dont feel much of a change in power and the boost meter doesnt go much past 2 or 3. (in 1000lbs/hg or whatever is the stock gauge units) Also, assuming my turbo is working right, is a turbo timer worth it?
> 
> Hopefully you guys can either assuage or confirm my fealing; either way, input would be nice. Thanks again in advance... one of these days ill get to be the knowledgable one helping out the less fortunate... instead of the other way around.


Turbo timers are a waste they are not necessary. You don't need one; as long as you don't run the car into the ground and then instantly turn it off it will be fine. How many miles on the turbocharger? If your hearing griding or anything it could be your starting to have excessive shaft play and as it spools up it balances out.

The oil leak is just where one of the screws on the valve cover is loose. If you tighten it the leak will go away. As for your brakes check your brake lines and especially the master cylinder. Most likely it is a bad master cylinder.


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## Xorti7 (Dec 27, 2004)

Thanks, I guess ill add that one to my wish list for sometime down the road.


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## Xorti7 (Dec 27, 2004)

About 170k on the turbo as far as i know. I checked with nissan and it hasnt been replaced, and the guy before me didnt even know where it was... so its pretty old. How can i correct this? or is it even dangerous?


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## JAMESZ (Mar 12, 2004)

Xorti7 said:


> About 170k on the turbo as far as i know. I checked with nissan and it hasnt been replaced, and the guy before me didnt even know where it was... so its pretty old. How can i correct this? or is it even dangerous?


It means the turbocharger is wearing out. Which means replace it.


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## Xorti7 (Dec 27, 2004)

How much do you think that would cost? Im just a guy with a minimum wage job here.


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## JAMESZ (Mar 12, 2004)

Xorti7 said:


> How much do you think that would cost? Im just a guy with a minimum wage job here.


400 maybe less for a good turbocharger. Install depends if you do it or not. Maybe 700 when all is said and done.


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## Xorti7 (Dec 27, 2004)

hmm, thanks, sounds like more than i want to put into it just yet. I guess ill just live with the couple psi im gettin out of it as long as its not damaging anything else.


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## asleepz (Feb 24, 2004)

JAMESZ said:


> Whoops your wrong. The CM 3in turbo back makes good power on otherwise stock cars. I don't feel like looking up a dyno graph so I won't spout any numbers but exhaust can make decent gains.


I'm assuming your talking about horsepower. Because it's not going to help on the gas mileage. And if it does it's 2>


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## JAMESZ (Mar 12, 2004)

♣AsleepZ♣ said:


> I'm assuming your talking about horsepower. Because it's not going to help on the gas mileage. And if it does it's 2>


It does alittle bit. Just as much as intake does. So yep me 2 you 0


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## Zen31ZR (Mar 24, 2004)

If the turbo is rattling/grinding, you'll want to replace that as soon as possible. Too much time at full boost, even 5-7 psi and the engine just might end up sucking in pieces of that compressor wheel...... The 84 Z I looked at the other day had this problem. The oil seals on the turbo were also destroyed, it was blowing clouds of oil out the exhaust. Won't be long before this happens to yours. Yours is an 88, so it probably has the T25 turbo, which is worthless after being overboosted a few times. 8-10 psi max on that turbo. It's unable to handle any more, structurally. You can swap to a T3 easy enough, if you have any junkyards in that area you should be able to get one cheap. You'll need the proper manifold from a 84-87 Turbo, and the T3 you can get from many cars made in the 80s.


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## Xorti7 (Dec 27, 2004)

Update, the sound im hearing is actually coming from the passenger side. I now know that its more of a pinging sound, like "ratt-tat-tating[shuffling] a set of metal playing cards". As far as i know everything on the car is stock. 

Is this related to the oil dripping from the valve cover and burning onto a metal cover over, what i thought originally to be the exhaust, the intake on the driver side? I understand this would heat things up a bit and cause this. Or is there something wrong with my fuel injection not suplying enough fuel? 

The sound comes on at low rpms and high throttle. So, although it comes on when the boost almost passes the 0, I think its the "predetonation" i hear about. Maybe this is just a normal function of these cars, but i havnt heard it before; I appologize for my ignorance. :cheers:


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## JAMESZ (Mar 12, 2004)

That description of the sound is right on with how people describe detonation sounds. Might be a wastegate issue or another boost issue. You could have any number of problems with the fuel system and it is going lean. And the oil leak will be fixed if you just tighten the bolts on the valve cover.


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## Xorti7 (Dec 27, 2004)

JAMESZ said:


> That description of the sound is right on with how people describe detonation sounds. Might be a wastegate issue or another boost issue. You could have any number of problems with the fuel system and it is going lean. And the oil leak will be fixed if you just tighten the bolts on the valve cover.


Alright, thanks man, i decided ill just try putting in 89 oct gas and see if it goes away.

As far as the leak i tighted the one bolt that the leak looked like it was coming from, but the leak is still there. How many bolts are there around the vavle cover? its at an angle so its probably trickling down from another bolt.

Edit: yea i was thinking it was related to boost. the boost comes on really late and is never as far up as i think it should be. Open throttle and full load show only about 1/2 the boost i think it should be showing. Where should the needle be at for full boost? at the end of the third of four segment right? well its not..


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## Zen31ZR (Mar 24, 2004)

You might have an exhaust leak on the passenger side. That will definitely affect boost, and can make a metallic sounding noise. 
Don't try tightening the exhaust manifold bolts, they'll probably just break off. Some may have broken anyway, which would cause that noise. The only way to do it right is to remove the whole manifold on that side, check and replace the gaskets as needed, make sure no bolts broke off in the head, remove them or get them removed if they did, get new bolts, reinstall the manifold, and torque to specs.


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## asleepz (Feb 24, 2004)

JAMESZ said:


> It does alittle bit. Just as much as intake does. So yep me 2 you 0



Still yet no proof.


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## JAMESZ (Mar 12, 2004)

♣AsleepZ♣ said:


> Still yet no proof.


Go find the proof or ask someone else that you trust. Or go ask one of your neighbors.


I wouldn't go near the exhaust manifold bolts unless your going to pull the manifold, and replace them.


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