Completed Project My 98 super charged EX

1998 Explorer 4.0 SOHC
Bought it with a melted alternator/wiring harness from a junkyard for $1,000
Fixed it, drove it for two weeks, then I boosted it.
Started with an M90 supercharger kit from www.Bansheesuperchargerkit.com
Upgraded to an M112 Lightning supercharger that was a prototype kit.
Next was the M122 off a 2012 GT500
I have reached 20 lbs of boost (with ARP head studs) and a 12.83 in a quarter mile.

Pictures
1. How it looked when I brought it home.
2.The M90 supercharger installed
3.The GT500 supercharger installed
4.How it looks now
5.Wheelie

 

[Dono]

That's what I love about you, nothing is an issue (except your trans ). Cool as a cucumber.

'If' my truck was actually working, I'd be stressing big time.

 

[4pointslow]

Cool and calm

My secret is having three vehicles. Race truck breaks down, so what, that just means more quality time in the garage.

Now when all three break down at the same time (has happened before), I completely lose it.

 

[2000StreetRod]

why three vehicles?

My wife periodically asks me why with only two drivers we need three vehicles. My answer is: one reliable vehicle (hers); one in the garage undergoing modifications; and one to haul the things for vehicle mods and yard/home improvements. So far, so good!

 

[4pointslow]

Vehicles

I always think of getting a 4th, but the insurance payments stop that thought process real quick. lol

 

[CDW6212R]

Do you have to have a 30" tire, as the two choices I was looking at come in both 29 and 30"? They come as 55 or 60 series, 275mm wide. I know the 30" tires give the most accurate speedometer, but the 29" tire will be lighter. I'm on the fence for that, I've been coming down in size to lose the tire weight.

The Nexen 275/60/17 is only $135 but the Toyo is around $150 for either size.

 

[4pointslow]

Tires and wheels

Do you have to have a 30" tire, as the two choices I was looking at come in both 29 and 30"? They come as 55 or 60 series, 275mm wide. I know the 30" tires give the most accurate speedometer, but the 29" tire will be lighter. I'm on the fence for that, I've been coming down in size to lose the tire weight.

The Nexen 275/60/17 is only $135 but the Toyo is around $150 for either size.

I have been looking at this site for a year now.
https://tiresize.com/chart/

I think I could go down to a 29. The problem I may have if I go any lower is running out of gear in 4th before the 1/4 mile is finished. Can not shift into 5th at WOT, would destroy the transmission.

I really would like to see a second gen explorer with 275/60/17 size tires on it. Please get them and post pictures of them installed. They may just be what I was looking for. According to the tire size chart they are 30.1 inches. But would they rub bad enough to not want them on my lowered explorer sport? The other things is if they don't hook up then I need to get drag radials instead. Traction is king at the track, slipping tires cause slower times and inconsistent runs.
I also will not run wheel spacers, they are not safe for my application. So I need to get wheels with the right back spacing/offset.

 

[CDW6212R]

I have a 275/60/17 spare tire, on a 2002-05 Explorer OEM rim. I test fit it but never intended to use it but for an emergency.

The 30" tire will fit great, but the wheel offset needs to be right. The SN95 wheels should all be in the 30mm offset range on the 8" wheels. I had the 94-97 Cobra wheels on my Mountaineer with 255/60/17's without spacers. But the clearance inboard was very tight, I had some rubbing on the parking brake cable(fixed by moving it inboard of the V8 strut bar in back). I then bought 1/4" spacers that I've used since(I had to with these 18's I have with 35mm offset).

So the ideal wheel offset should be in the 20-25mm range. The 17x9's I found this Summer have 16mm offset, which places the wheels outboard about as far as you dare to go.

The front clearance issues are the upper ball joints mainly, and wider tires will rub the sway bar at full lock(no big deal). In the back the side to side movement of the truck in cornering will reach the tires on the inside. So the back needs lots of room from the tire inboard to the body/frame and parking brake cable.

Here's that 275/60/17 spare next to my first 265/60/18's(30.5" tall).

 

[4pointslow]

Tread width

What is the tread width on that tire? The section width is supposed to be 10.8 but what is the actual tread width? Can you measure it for me?

My 255 70 16's are only 7 inch wide, the wrangler RTS's are known to be a little on the skinny side when it comes to tread. The section width is listed as 10.2
That is pretty crappy to have a tire that is 10.2 wide but the tread is only 7 inches wide. Better for gas mileage, but not for traction.

Here is another thing that gets me frustrated, I measured my 31 10.5 15 off my ranger and it is only 29 and maybe a half inches. What? I know I did not wear an inch and a half off the tire. You buy a 31 inch tire and think it is 31 inches only to find out it is not. So if I buy two 30 inch drag radials hoping to use them on the rear with my stock tires(30 inch) on the front then are they going to be 28.5 inches and mess my transfer case up. This world just pisses me off sometimes, things always being called what they are not just to sell more. I mean crap, Subway even got sued because their foot long was only like 11 inches. End rant. lol.

 

[CDW6212R]

Most AWD systems will not tolerate enough diameter difference to let you run two different tires. Meaning that it is possible to find some sticky tires for the back which will be effectively the same as the fronts. But the chance of finding them is very slim, it'd take buying lots of tires to do actual testing with.

As you said, the specs of a tire will not be accurate(enough) to help you compare tires well, let alone match them up successfully on your A4WD or any AWD.

I'll measure this Goodyear tire I have tomorrow for its tread width. Different brands have tire sizes that rarely match another brand's actual sizes. So I'd tend to go by reviews of how good the traction of a tire is, and real experience with a tire of course. I've only had a few sets of tires that to me were "sticky", and not like most that seem too hard(spin easily).

 

[CDW6212R]

Okay, this 275/60/17 is a Goodyear Eagle GT II, and the tread at a glance looks like a good 10". But with a measuring tape it's basically right at 9" wide. I don't know if this tire is listed anywhere still to see what the specs would call the tread width. But other tires will have similar differences in the actual widths, versus what the specs list them as.

 

[2000StreetRod]

tires specs

Tirerack.com lists more complete specs for the tires they sell. For example the Goodyear Eagle RS-A P275/60R17 has a section width of 11 in., a tread width of 9.1 in., a dia. of 30 in. on an 8 in. wide rim. It is suitable for rims between 7.5 and 9.5 inches. Tire weighs 32 lbs and runs 697 revs/mile.

 

[CDW6212R]

Tirerack.com lists more complete specs for the tires they sell. For example the Goodyear Eagle RS-A P275/60R17 has a section width of 11 in., a tread width of 9.1 in., a dia. of 30 in. on an 8 in. wide rim. It is suitable for rims between 7.5 and 9.5 inches. Tire weighs 32 lbs and runs 697 revs/mile.

That is a light tire for that size, most will be in the 36-38lbs range. The Toyo and Hankook tires are among the highest rated available in that size, but the Tire Rack doesn't carry those.

I browsed for a bigger tire, 285mm or 295mm, but the only size that may be available is a 295/50/17. I really doubt that would fit in the front, so the 275mm section width may be the best limit.

 

[4pointslow]

9 inches

So my stock tires are 7 inches wide, and the 275 would be 9 inches wide.
Do you think that would be enough of a difference to stop wheel spin off the line? Maybe I should just get drag radials.

I looked at the back and there is room for a 10 inch wide tread, and probably enough for the section width to go along with that, maybe an 11.something section width.

I was using the 31 x 10.50 15 off my ranger to get a comparison, it too was 9 inches wide(tread width) and left room for at least another inch with the proper back spacing and rim width. It looked like it would even have wiggle room for the rear to shift side to side. So maybe a 10 inch drag radial. A 15 x 9 with 6.5 inch back spacing(+38mm offset)would work if they make one, I don't think they do.

 

[2000StreetRod]

from 7 to 9

Going from a 7 inch wide tread to a 9 inch wide tread on all 4 wheels would be a 28% increase in traction. Do you think your whp increased by more than 28% when you increased the boost?

 

[4pointslow]

%

Is the HP what I should look at or the torque?
Does torque or hp increase equal traction decrease? vise versa.
I have been up since 3:30 am so if what I type doesn't make sense, that's why. hahaha lol.

 

[CDW6212R]

So my stock tires are 7 inches wide, and the 275 would be 9 inches wide.
Do you think that would be enough of a difference to stop wheel spin off the line? Maybe I should just get drag radials.

I looked at the back and there is room for a 10 inch wide tread, and probably enough for the section width to go along with that, maybe an 11.something section width.

I was using the 31 x 10.50 15 off my ranger to get a comparison, it too was 9 inches wide(tread width) and left room for at least another inch with the proper back spacing and rim width. It looked like it would even have wiggle room for the rear to shift side to side. So maybe a 10 inch drag radial. A 15 x 9 with 6.5 inch back spacing(+38mm offset)would work if they make one, I don't think they do.

That is a very big change. Gaining 2" of tread width from a 20mm wider tire(255 to 275mm), that's a great improvement. You are using four tires for traction, so it should help a lot given quality rubber(some tires just don't grab well).

BTW, I drive a USPS truck with recap tires(4), and it slips and slides on wet pavement. Yesterday I got stuck on a steep driveway with leaves on it(a curved slope too). I barely was able to set the parking brake and it not slide back, got out and spent ten minutes brushing leaves away with my shoes and a board I found.

If the 275mm size will work for you, do the math and see if you have to have the 30" size(60 series). The lighter 29" size would be a hair quicker. I want it for the weight, and better handling, being shorter. They look about the same on these trucks, 29" or 30" tires.

 

[2000StreetRod]

use the torque

Actually, it probably is more accurate to compare the wheel torque instead of wheel hp. Horsepower, in my opinion, is an outdated measurement of performance. hp = (tq * rpm)/5252 where 5252 is the conversion factor for hp defined as 550 ft-lb/sec. It all seems rather confusing to me but if you look at the torque at stall speed I suspect that's as good as any method. The max tire friction (and acceleration potential) occurs when the tires are not slipping.

 

[4pointslow]

Tire

What size is the 29 inch tire?

The traction problem is due to cold weather and poor track conditions too, not just the little HP and Torque increase. I had tire slip last year also.

In September when it was warm out, and I was at Maple Grove with a newer track surface, I only slipped once during time trials. The day warmed up and so did the track. Warm track is sticky and helps a lot with traction. But cold air makes my engine happy! lol.

I believe it is just the rear tires slipping, but you know I can not see them when I am driving. lol. I need a spotter.

 

[4pointslow]

Ft lbs

Actually, it probably is more accurate to compare the wheel torque instead of wheel hp. Horsepower, in my opinion, is an outdated measurement of performance. hp = (tq * rpm)/5252 where 5252 is the conversion factor for hp defined as 550 ft-lb/sec. It all seems rather confusing to me but if you look at the torque at stall speed I suspect that's as good as any method. The max tire friction (and acceleration potential) occurs when the tires are not slipping.

It was about 20 ft lbs of torque increase at around 3,000 so that would be aprox 6% increase in torque.

It is not just the small increase in torque causing slip, I had the same problem last year when it was real cold out and the track was not at it's best.

If going from 7 to 9 inch wide tires would do the trick that would be great.

 

[vroomzoomboom]

i can tell you this, trying to shove a 10 inch rim in the back is going to be real tight. that and you may have to do what i did when i bought my rims and tell them they are for something else and run spacers.