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PostPosted: Tue Jun 17, 2008 2:09 pm 
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Mike, you know or you beleive? it is possible, those numbers indicate a slightly bigger tooth size as there are about 5 teeth less in that combination.

90Metro, swapping out fifth gear involves taking the black cap off the end of your gearbox, removing an allen key bolt, 2 circlips and then undoing the large 26mm nut on the end of the countershaft, sliding the 2 gears and shifter fork off, installation is the reverse.
On a 3 cyl you have plenty of room to do it in situ but a 4cyl would require lowering the engine and box down 4 inch's to get clearance.


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PostPosted: Wed Jun 18, 2008 6:58 pm 
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Thought I should add these links and comments here.


http://www.metrompg.com/posts/tranny-swap.htm
Doing the 4.4 to 3.5 tranny swap nets an rpm loss of 25% in 5th gear which gives approx 5-6% improvement in fuel economy.

"From the very first test drive, I loved it. The swap turned the car into a long-legged beauty. First gear isn't at all unmanageable on the flat, the gearing suits my driving style perfectly. Very happy."

... also ...

http://mypeoplepc.com/members/tleone/gears/
The Escort started with a 0.755 5th, then to 0.717, and finally with a 0.546. This is a 24% drop in rpm. About the change (from 0.717 to 0.546), he says:

"I'm very pleased with the new overdrive. Lower RPM makes the car much quieter on the highway, and there is still plenty of torque reserve for small hills. It is a fairly large step from 4th gear to 5th, but I don't find it objectionable.

My analysis indicates that I should expect about 10-12% improvement in highway fuel economy. My driving is about 80-90% highway, and I have measured an average benefit of 6% during 2100 miles of driving. Details are in the "Fuel Economy" link above. "


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PostPosted: Wed Jun 18, 2008 8:07 pm 
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Dattman wrote:
A standard metro with 4.1 would normally be doing 2900rpm@60mph and the 0.657 would drop that down to 2513rpm.

so can we expect a fuel saving of 100x400/2900=13.8% ???

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daily driver: red 1991 Metro 3cyl 5sp, roof rack, 8 degree advance,
got 61 mpg combined on 14" tires but i prefer 12"

completed frame up restoration: black 1994 Swift GT 5sp -- like new ! 45mpg


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PostPosted: Wed Jun 18, 2008 10:32 pm 
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xrw44 wrote:
Dattman wrote:
A standard metro with 4.1 would normally be doing 2900rpm@60mph and the 0.657 would drop that down to 2513rpm.

so can we expect a fuel saving of 100x400/2900=13.8% ???


Nope. The reduction in rpm is about 13% which is about half the 25% reduction in the above examples, so your gain would be about half as well. Figure around a 3% gain in economy. But, it should be much easier to implement than a tranny swap.


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PostPosted: Thu Jun 19, 2008 2:35 am 
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OK, I have good news and I have bad news.

The bad news is the helical gears are going to cost twice as much as straight cut gears which is what I normally get made, helical gears must be ground and this is very labour intensive and expensive, in fact over 40% of the cost is due to grinding the gears.
There are a few technical issues which dictate that a donor 5th gear on the countershaft is required, cut off the teeth and press on a new bigger gear as it's not economic to mill the synchro teeth on the gear.
The gear on the input shaft will/would be a whole new gear.

The cost works out to US$1150 + postage + your 5th gear and selector fork. ( I have cores so could be posted to me after the new gears are installed)

Now the good news :shock: I think I can squeeze in one extra tooth so the ratio will be 0.611, due to the horrendous cost I am determined to get the tallest ratio possible.

If your standard metro was doing 2900rpm @60mph in 5th then the new gear would drop that to 2338rpm.

If this project is ever to go ahead I would need at least 3 confirmed orders otherwise the single unit price would be way more expensive.
It's just not economic to make one, if I could make 20 or so then the cost would be way more reasonable, I can assure you guys I would be making almost no profit if this project did go ahead.

For the mk1 guys, thanks for your pm's, cost would be about the same, I need to physically check the clearance as we might have to use a different ratio and again I would need 3 confirmed orders before I started as the input shaft gear is different so requires different tooling from the mk2/3 gears.

Let me know if anyone is still interested...


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PostPosted: Fri Jun 20, 2008 3:09 pm 
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martinq wrote:
Figure around a 3% gain in economy. But, it should be much easier to implement than a tranny swap.
Thanks to martinq for his effort.
I hope i am wrong but the gear at 1200 is NOT a sound investment. :(
We'd have to drive 33k miles per yr for 10 YEARS to match crappy bank interest. :(
Details:
At $4/gal and 50mpg i am paying 8 cents per mi. the gain in economy saves 3% of 8 cents = 0.24 CENTS per mi. the $1200 gear will be paid off in $1200/$0.0024= 500,000 miles and then i start saving money. (not counting labor) Will the gear will last 500k miles? will the trans? will I? no. :cry:
We'd have to drive 33k miles per yr for 10 YEARS to match crappy bank interest. :(
i can put 1200 in the bank and make 36 per yr. After driving 1,000,000 miles we have made 100% on our 1200 invested.
The gear at 1200 is NOT a sound investment. :(
What if the gear was $120 and gas was $8 you ask?
$0.0048 per mi saved
gear is paid for in 25k miles. :D
At 35k miles we match crappy bank interest. 2-3 yrs is a better investment return.
But at $4 per gal the gear would have to be $60. :roll: unlikely!
At $4 per gal and $120 gear (incl shipping) we need to drive 70k miles to really start saving because the 120 could be making 3% in the bank. I hope i am wrong. :cry: :cry: :cry:
Too bad -- Thanks to martinq for trying.

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looking for:
the time i mispent in my youth

daily driver: red 1991 Metro 3cyl 5sp, roof rack, 8 degree advance,
got 61 mpg combined on 14" tires but i prefer 12"

completed frame up restoration: black 1994 Swift GT 5sp -- like new ! 45mpg


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PostPosted: Fri Jun 20, 2008 4:55 pm 
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xrw44 wrote:
Too bad -- Thanks to martinq for trying.

WTF, I had to take 2 hours off work to see the gearcutters to figure this stuff out for you guys, I was never going to make any money out of it, I'm just a gear ratio geek and like solving problems, it's just this problem is uneconomic to solve at this stage.
It all depends if you are desperate enough to get into the 60mpg club :lol:

Anyway I've just picked up a 2005 swift box so my next project is making some go-fast gears for the brand new swift :twisted:


Last edited by Dattman on Fri Jun 20, 2008 4:57 pm, edited 1 time in total.

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PostPosted: Fri Jun 20, 2008 4:57 pm 
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xrw44 wrote:
Thanks to martinq for trying.


I really appreciate it, but it's Dattman who you should be thanking as he started the thread and did more 'leg-work' than I did ... even though we were both thinking about it at the same time. :)


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PostPosted: Fri Jun 20, 2008 4:59 pm 
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Hehe, I posted faster, thanks :D


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PostPosted: Fri Jun 20, 2008 5:02 pm 
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[OT] Isn't that because you have a close-ratio 1-2 ?!!???

=P
[/OT]


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PostPosted: Fri Jun 20, 2008 5:05 pm 
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Yes, and I post even faster when it's raining, I get much less fingerspin when I'm typing :lol:


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PostPosted: Fri Jun 20, 2008 5:49 pm 
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I should add that I may have a slightly cheaper alternative from a source here in Canada. I will post more information when I have something solid.


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PostPosted: Fri Jun 20, 2008 8:34 pm 
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Dattman wrote:
xrw44 wrote:
Too bad -- Thanks to martinq for trying.

WTF, I had to take 2 hours off work to see the gearcutters to figure this stuff out for you guys, I was never going to make any money out of it, I'm just a gear ratio geek and like solving problems, it's just this problem is uneconomic to solve at this stage.
It all depends if you are desperate enough to get into the 60mpg club :lol:

Anyway I've just picked up a 2005 swift box so my next project is making some go-fast gears for the brand new swift :twisted:

:oops: my mistake. Thanks to Dattman for his research.

_________________
looking for:
the time i mispent in my youth

daily driver: red 1991 Metro 3cyl 5sp, roof rack, 8 degree advance,
got 61 mpg combined on 14" tires but i prefer 12"

completed frame up restoration: black 1994 Swift GT 5sp -- like new ! 45mpg


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PostPosted: Sat Jun 21, 2008 4:11 am 
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xrw44 I think you'll get a much bigger saving than 3%, on a standard metro using a 0.611 gear you would drop your rpm from 2900@60mph to 2338rpm@60mph, I would expect to see at least 6-7% improvement on the open road.

Bad news for the mk1 guys, I measured up a mk1 box today and there is even less room between 5th gear and the selector fork than on a mk2/3 box, you simply cannot get any bigger gear than 0.657 in there, personally it's not ever going to be worth a custom 5th gear for a mk1.

I do think that the 0.611 gear for the mk2 box is still a good idea, if you want anything lower you would need to make a custom selector fork to give the required clearance, then you could use 0.56 or even as low as 0.52, as it is the 0.611 gear will require quite a bit of work to fit and would involve making the gear narrower so that less grinding of the selector fork is required.

Either way it's a lot of work and unless you got the gears made in China you will never get the price down to US$600-700 which is about the maximum most people would pay.

Best bet is to change to a 3.52 final drive.

D


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PostPosted: Tue Jun 24, 2008 12:31 am 
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Aw shucks!
Thanks indeed for taking the time to look into it!
Even if it would take a whole lot of miles to make it cost effective, the satisfaction of having nice city gears and then that wicked highway 5th would be worth quite a bit in satisfaction. Be sure to keep us posted if it looks like you're going to have some made. I can't claim to be SERIOUSLY interested but I do have a MK4 box that I could fab some mounts for........ tempting...
And THANKS again!

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BUT IT'S GOT A HEMI!!
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PostPosted: Fri Jul 25, 2008 2:54 pm 
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All right, to say the least, I'm a tad bit confused here. I have a '87 1L non-turbo Sprint with 5-speed manual. How do I know what my final drive is?
What would be the best way to drop my rpm's in high gear?
Change out 5th to a taller gear?
Replace the tranny with one (if there is one) that has a taller 5th? Are the other years mk's interchangeable with mine?
Put larger diameter tires on it, if there's room under the fenders? I know this would raise the body. Would this have a detrimental effect on economy? Also, I'd have to re-configure my speedo if I did this.
Or is there another possibility that I've overlooked?
Too bad no one makes a 6-speed to keep my current 5 and add an overdrive for cruising.


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PostPosted: Sat Jul 26, 2008 5:04 am 
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1Ray wrote:
All right, to say the least, I'm a tad bit confused here. I have a '87 1L non-turbo Sprint with 5-speed manual. How do I know what my final drive is?

Pretty much all 1.0/1.3 boxes have the same gears, 0.758 5th gear, Final drive for your car is 4.1.
The only way to lower the cruising rpm is to use a lower final drive, in the states the xfi had a 3.85 fd, in NZ and Australia the 1.3's came with a 3.52 FD.
I have a waiting list of 5 people so far for a 3.52 FD to fit 87/88 sprints :| if you had an earlier type sprint with leaf springs then I have a 3.52 FD for sale to suit.


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PostPosted: Sat Jul 26, 2008 9:48 am 
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1Ray wrote:
All right, to say the least, I'm a tad bit confused here. I have a '87 1L non-turbo Sprint with 5-speed manual. How do I know what my final drive is?
What would be the best way to drop my rpm's in high gear?
Change out 5th to a taller gear?
Replace the tranny with one (if there is one) that has a taller 5th? Are the other years mk's interchangeable with mine?
Put larger diameter tires on it, if there's room under the fenders? I know this would raise the body. Would this have a detrimental effect on economy? Also, I'd have to re-configure my speedo if I did this.
Or is there another possibility that I've overlooked?
Too bad no one makes a 6-speed to keep my current 5 and add an overdrive for cruising.


I have a '87 1L non-turbo Sprint with 5-speed manual. How do I know what my final drive is?
The best way is to search this forum.
There's a nice post with a flow chart by Dattman which tells the differences from the outside.
Image
Your final drive if stock:
http://www.teamswift.net/viewtopic.php?f=9&t=14845
G10 std mk1 with 3.789.

Change out 5th to a taller gear?
That is what this thread is about; custom made gears vs. swapping out the entire transaxle...
...cost vs. the desire to have the exact ratio desired.

Replace the tranny with one (if there is one) that has a taller 5th?
There is a 3.52 which you can use. Many of us have done it.
I have an MK1 5 speed which has the transaxle/final drive 3.52 and it's a hoot.
Not too many modern cars try to keep up with me over 85 mph.
Check Manutea's threads; he praises the swap highly.
However, his swap involved pulling the gears out and changing them, rather than swapping the entire box.
Here is a picture of the easiest swap, again...thanks to Dattman:
Image
It wasn't his intention when he posted the picture, but you can see how you will have to make a little bracket when you put the 1.3 trans in, right?

I'll add that your stock transmission is very close in final drive ratio, so you won't see as big a difference.
I also have a stock 87 4 door with the same final drive as you are supposed to have, and it moves along on the highways very nicely without the need to swap to a higher geared 5th. Mostly, it's the Geo and Metro people with the final drives in the 4.1 area who are concerned with this type of thread.

Are the other years mk's interchangeable with mine?
Yes. Again you will have to search to find the exact transmission combinations and adaptations you will need to perform.
http://www.teamswift.net/viewtopic.php?f=9&t=14845
Is great reading.
Some require changing the guts; some you just swap over the trans and add a bracket.

Put larger diameter tires on it, if there's room under the fenders?
You've already done that with your 155's. Mileage suffers mildly...basic law of physics:
more rotating mass.
Stock was 145.

I know this would raise the body. Would this have a detrimental effect on economy?
Yes, and yes.
However, if you can find the stock 145 tires, my guess is they're over 10 years old.

Also, I'd have to re-configure my speedo if I did this.
There are several speedometer gears; different colors; orange and white are two examples.
Each has a different number of teeth to compensate for the final drive ratio.
viewtopic.php?f=9&t=31702
This thread tells of the different gear ratios and speedo gears/colors.
Should be required reading, no?

Or is there another possibility that I've overlooked?
Question is too broad, but...yes there is.
You could take apart the speedometer, and redo the face.
Or, you could buy a GPS, and use that.
They are highly accurate, and you can search the "How fast have you driven" thread to see pictures of them in use.
Probably other options, but not in the scope of this reply...

Too bad no one makes a 6-speed to keep my current 5 and add an overdrive for cruising.
If someone does, it's not common knowlege.
Your MK1 gets great mileage once you get your carburetor dialed in.
If you aren't getting a consistent 45-55 mpg, there's something wrong.
Adding a gear/changing to a different final drive in YOUR car will not have a significant increase in mileage.
Figure 60-65 miles per gallon versus 50-55 miles per gallon...what kind of mileage are you after?
Our 87's are the lightest of all the cars on this forum, so we have the natural advantage.
It's the Metros and the Geos trying to get the mileage we currently have that makes for these kinds of threads.
Don't feel too bad that no ones makes a 6 speed for our cars...OK? Trust me, mileage wise, they're all jealous. :thumbsup: :thumbsup: :thumbsup: :thumbsup: :thumbsup: :thumbsup: :thumbsup: :thumbsup: :thumbsup: :thumbsup:
Hope this clears up some confusion.

Now, I've got to get ready to head to the junkyard....

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Once you get the cars dialed-in (compression, leaks, bearings, alignment, brakes) swap in new rubber and glass, you've got something which should last for years!


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PostPosted: Sun Jul 27, 2008 6:55 am 
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I have the 145R12 tires and I do get mid 50's mpgs. My last tank checked 53, so I'm definately not upset about my mileage. My brother in law has a newer Metro and the best he seems to get is around 44-45. I found 1 place in Wichita that sells new 145R12's. I say new, I really don't know when they were made. But this is a very interesting thread. Lots of good info. Thanks for the reply.


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PostPosted: Sun Jul 27, 2008 8:24 pm 
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You can look at the tires.
There is a DOT number on the sidewall.
The last 3 or 4 numbers will tell you when it was made.
If 3 digit, last number is the year.
If 4 digit, last 2 numbers is the year.

Personally, I think you are lucky to still be running 145s.
They are available in Europe, etc.
But not here.

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DIY Wheel Align: viewtopic.php?f=2&t=42479
Once you get the cars dialed-in (compression, leaks, bearings, alignment, brakes) swap in new rubber and glass, you've got something which should last for years!


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PostPosted: Sun Jul 27, 2008 11:12 pm 
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Phil N Ed wrote:
Personally, I think you are lucky to still be running 145s.
They are available in Europe, etc.
But not here.

I don't see why you'd want to run a 145R12 tire. There should be lots of selection in the 13" range and you can get a bigger OD while you're at it to improve your milage. A quick search on 1010tires brings up 20 tire models for 13".

http://www.1010tires.com/tires.asp

The biggest OD I've run was a 24.2" (185/70-14) but there was rubbing at tight turning. You can get close to that size with a 155/80-13 (22.8"), or better yet a 175/65-14 or 175/70-14 (23.0" and 23.6"). The 175R14 search brings up 26 tire models so there's lots and lots to choose from.


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PostPosted: Mon Jul 28, 2008 12:23 am 
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martinq wrote:
I don't see why you'd want to run a 145R12 tire.

You are in the majority.
If he changes tire size, his 'miles per gallon' will drop.
If he goes to the wheel and tire combinations that you have mentioned, his 'miles per gallon' would drop.

There are other considerations besides 'miles per gallon'.

Some people change to the tire sizes that you like because of looks, handling, etc.

He is running 145's and gets over 50 miles per gallon.

Don't you think that's pretty good?

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DIY Wheel Align: viewtopic.php?f=2&t=42479
Once you get the cars dialed-in (compression, leaks, bearings, alignment, brakes) swap in new rubber and glass, you've got something which should last for years!


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PostPosted: Mon Jul 28, 2008 12:31 am 
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Dattman wrote:
Best bet is to change to a 3.52 final drive.

D


do that, AND put the 5th in there!

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PostPosted: Mon Jul 28, 2008 8:10 am 
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Phil N Ed wrote:
martinq wrote:
I don't see why you'd want to run a 145R12 tire.
If he changes tire size, his 'miles per gallon' will drop.
If he goes to the wheel and tire combinations that you have mentioned, his 'miles per gallon' would drop.

If the stock size is 145/80-12 (21.1" OD, 66.3" Circ) then his engine is running significantly faster than if the size was a 175/70-14 (23.6" OD, 74.1" Circ) at a given speed. That tire will give you an rpm drop of just over 10% and should realize significant increase in fuel economy. Putting on bigger wheels is like reducing your final drive.

The only down sides would be:
- heavier wheel/tire might not ride over bumps as smooth do to increase unsprung mass
- the wider contact tread might increase rolling resistance (but much of this is due to the rubber compound)


Phil N Ed wrote:
He is running 145's and gets over 50 miles per gallon. Don't you think that's pretty good?

Why settle for good? Why not make it better?


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PostPosted: Mon Jul 28, 2008 1:38 pm 
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I don't have enough data to have this be totally convincing but....

On a Ford Fiesta I went from a 155R12 to 175/70/13 and went from 35mpg down to 32mpg. So in spite of the larger diameter I lost some decent mpg, probably due to width and higher ride height.

On my Sprints I went from a 155R12 to a 155/60/15 and probably went from...39mpg in mixed driving up to about 46mpg in mixed driving.. probably better on the highway. I got to run higher PSI in the 15s and they're about 6% larger diameter but are heavier.. similar tread width.. a little wider at the wheel but more aerodynamic.

For my highway car I'm going to stay with the 155/60/15's (unless I can find narrower rims and use the 145/65/15s), lower the car a little to compensate for the taller wheels/tires, and put in the 3.52 FD. Oh yeah! And hopefully put in one of SuprF1y's econo cams!
I'm slow at getting things done but I'll let ya know how it goes!

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87 Chevy Sprint Plus
It may only have 3 cylinders and be less than 1 liter.....
BUT IT'S GOT A HEMI!!
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