Another METRO Project

[Gasoline Fumes]

Originally Posted by MPGeo

On another note, I lifted the car and counted tire revs vs engine revs while on 5th gear. And for every 1 engine rev my tires rotated only 0.75 revs aprox. Any coments on this?

If you had only one wheel off the ground, the math says 3.5198. Which is pretty close to 3.52!

[MPGeo]

Originally Posted by Gasoline Fumes

If you had only one wheel off the ground, the math says 3.5198. Which is pretty close to 3.52!

Thanks for both comments this one and the volt meter one!

Yes I did have only one wheel of the ground... Q? What is the formula you used to get your #s? I would like to know just for future reference. Thanks.

[Daox]

If you're interested, I made a vacuum gauge pod for my Metro. I later added a voltmeter to it. It got mounted by one of the screws that holds the dash bezel in. If you're interested in it, PM me and we can work something out.

Here is a picture and link to my thread:

http://ecomodder.com/forum/showthrea...tml#post502197

[MPGeo]

So the tach cluster came in the mail today, and I installed it today.

Since it had a different mileage reading than my car's original mileage readings anyways, I decided to make the odometer numbers count for something. So as soon as I took it out the box I disassembled it, removed the speedometer section and took it apart and changed the odometer readout to reflect actual engine mileage since rebuild. This way I can ""accurately"" track mileage on engine since rebuild. I keep good records, so I will be also able to track total mileage on chassis for inspection purposes.

No pics... It's just a tach, But is nice to be able to see my RPMs finally. Thanks GAS FUMES. My MPH reading is way off, it's my fault for removing the needle. But I will be adjusting/calibrating the needle soon.

[Ecky]

In my Del Sol I chose to set the chassis mileage on the cluster and do math for the engine. I also pulled the needle off like an idiot, and had to tweak it several times before it read true again.

[Gasoline Fumes]

Originally Posted by MPGeo

Thanks for both comments this one and the volt meter one!

Yes I did have only one wheel of the ground... Q? What is the formula you used to get your #s? I would like to know just for future reference. Thanks.

I converted your measured number to 1.333 revs of the engine per one rev of the wheel. Then I divided by the 5th gear ratio of 0.7576. That results in 1.7609:1. With only one wheel off the ground, wheelspeed is doubled. So I doubled the result, getting about 3.52:1. I'm pretty sure I did the math right, less sure I'm explaining it well!

[MPGeo]

Originally Posted by Gasoline Fumes

I converted your measured number to 1.333 revs of the engine per one rev of the wheel. Then I divided by the 5th gear ratio of 0.7576. That results in 1.7609:1. With only one wheel off the ground, wheelspeed is doubled. So I doubled the result, getting about 3.52:1. I'm pretty sure I did the math right, less sure I'm explaining it well!

Thanks, I wasn't exactly sure how to do that one. Thanks

Originally Posted by Ecky

In my Del Sol I chose to set the chassis mileage on the cluster and do math for the engine. I also pulled the needle off like an idiot, and had to tweak it several times before it read true again.

I gess that makes more sense... But for whatever reason I leaned towards engine miles

[MPGeo]

So the results after the few mods I did are pretty good.

I have modified my driving speeds and this last tank I was able to get
55.02. This is my best tank to date.

Since I just installed the tach cluster yesterday I was able to drive the last leg of the tank while being able to see RPM readings and how they are correlating to GPS speeds.

I'm pretty sure I can squeeze a little more FE just by driving based on RPMs rather than by GPS seep alone now that I can clearly see what I've been doing and what I can do RPM wise. And although I would love to do another few tanks based on RPM driving techniques to see what the improvements might be (if any), I will have to settle with the 80 or so miles I was able to put on the tank today solely base on RPMs, because I'm ready to put the taller tires on.

I'm ready break into the 60mpg range, so part of me feels like just throwing everything at it at once... But the other part of me wants to be more methodical and actually see what the improvements are for the mods...

To Be Or Not To Be??? Either way, I'm putting on the tires this weekend

[MPGeo]

Ok, so now that I've had my Tach for 3 days ... figured it was time to put it to some good use and record some measurements before and after tire swap, here's what I came up with:

Here's some more pics and size comparisons













These tires are very big. And you can see in the pictures they barely fit.

With the front suspension still off the ground I did some clearance inspections and the tires WILL make contact on the sheet metal towards the rear - feet rest area - of wheel well. The is no contact towards the front side of wheel well only the rear side. But the contact only happens when turning the wheels almost to it's max turn radius position.

I figured I would try driving around int them anyways, and be conscious about not fully turning the steering wheel, which I normally don't do.

I was pleasantly surprised to find out that I can drive it as normal without any major rubbing issues. 90degree turns @ stop signs - no problem. But there was some rubbing on extreme turns, but only on the passenger side, and not where I was expecting. It turns out the the outer portion of the tire, and only on the empty side of the car, will rub on certain turns with the plastic inner lining of the wheel well as shown. This was very unexpected. So in fact, in my case, tire rub is almost a non-issue.





I'm more concerned with the angle of attack the car now has due to the miss-matched tires, and feel this will be counter productive. But I don't have another set of tires to put in the back to even it out. I didn't want to lower the car until I had chosen what tire size I was going to stick with... and if I wind up with these, there won't be much lowering Better under body aero work would definitely be a must if this size works out.




As far as engine performance, well you can compare RMP vs SPEED above, but on the 10 or so miles tested for each tire size 1/2 of the trip was all highway, the other return 1/2 trip was via country roads.

Acceleration & Top Speed were negatively impacted grately. I don't have a scan gauge, so I can't provide actual #s, but I know that my throttle was opened to a greater % and duration during acceleration as compared to the 12's, but I barely had it open to maintain the speed... I couldn't even get to 3,000 rpms on the highway @ WOT for 5-10 secs so I stop trying... No need since I could reach 70mph by 2,600. The highest speed I was able to reach with the 15's was 73.68mph WOT and not really climbing With the 12's I had done the same (WOT) and reached 86mph (down hill )

I did all my testing prior to fill-up, and filled up at a gas station about 1/2 mile away from the house... Starting tomorrow I will be testing the 15's and I should have gone through a tank by Thursday. Unless the change is drastically worse, I will probably run this setup for a few tanks and see what I really think about it.
SO... ANY BETS ON WHAT EFFECTS THIS WILL HAVE???

[me and my metro]

I think your mileage will be less, you have the tallest gear ratio with the smallest engine. My 1.3L did fine with 205/50r15 and the 3.5 final but I had 70 hp not 49 Xfi hp.