How to get the most out of a basically stock rig

I KNOW JEEPS ARENT RACECARS(TRUCKS?) I AM JUST LOOKING TO HAVE SOME FUN.

Here are the specs of my 1990 MJ

Homemade FIPK
no cat, glasspack
4.10's
AX-15
4.0L

Im thinking of going to the local 1/8th mile for some fun next year. What are the best ways to get the best times out of these rigs.

Just playing around I have found shifting at 4500rpm seems to work better than 5,000 since there really isnt any power up there. What should I do to get all I can out of it. Without hurting it in the meantime

Remove as much as possible.

Rear seat, carpet, stereo equipment, etc.

The saying goes, "0.1s gained for every 100 lb lost."

put a late model intake on it (equal length runners) easy to get not expensive and great bang for the buck difference.

Put a cat on it to regain the lost tourqe.

Rev

Since it's going to be wide open throttle it might be better to have an open exhaust. He's going to be in the high end most of the time so I think it will start hurting more than helping to choke off his exhaust. Keep the glasspack there but shorten your exhaust to maybe a foot past the muffler.

Like the guy said above lose weight, take as much stuff out of the Jeep as possible pull the seats if you want to, take trim off (lots of it is metal).

Lower it if you can or want to because wind resistance is evil to acceleration too. Change to tires that are thin in the front if you can also and put good street tread on the rear for off the line traction. Running big fat all terrainers is not good either becasue of rolling resistance and the fact they are heavier too.

Not much you can do if you are just looking for freebie or cost effective performance on the drag.

Just know that weight and wind resistance are the biggest factors for drag racing.

use a 62mm TB and a custom down tube (those are the bigger restrictions on a stock engine) after that you can go for a Map adjuster or a adjustable fuel Pressure regulator. An airdam will help you can use a S-10 one as Dr. Dyno did. A good header (Banks, Borla or Clifford) and maybe after all this a Stage 2 Jet Chip.

Copy the mods that I did to my XJ before I built the 4.6 stroker, and shed as much weight as possible from your Jeep (that includes yourself if you're carrying a Michelin around your waist ).

summitlt said:

I KNOW JEEPS ARENT RACECARS(TRUCKS?) I AM JUST LOOKING TO HAVE SOME FUN.

Here are the specs of my 1990 MJ

Homemade FIPK
no cat, glasspack
4.10's
AX-15
4.0L

Im thinking of going to the local 1/8th mile for some fun next year. What are the best ways to get the best times out of these rigs.

Just playing around I have found shifting at 4500rpm seems to work better than 5,000 since there really isnt any power up there. What should I do to get all I can out of it. Without hurting it in the meantime

Click to expand...

Jeeps are'nt race cars but for a daily driver you dont need to be...superfast as mainstream car enthusiasts tout. What you need is solid torque "off the line" and then the hp to keep it going. The XJ provides this copiously, stock form or modified. They used to say the Cherokee was the king of the stop light drags until the GMC Cyclone came along. I would follow Dino's tips to make your XJ move with alacrity.

It's kind of funny though that it had to be a sports oriented truck with forced induction (with intercoolers) to rival the regular 4.0 liter Cherokee. But then again I've heard that cherokees were capable of walking away from supercharged araura's too.

XJ Saga said:

They used to say the Cherokee was the king of the stop light drags until the GMC Cyclone came along.

Click to expand...

You got that right. Here's the quote from the Car & Driver March 1992 issue when they road tested the GMC Typhoon (not the Syclone):

"Until now, the top gun in the sport-utility stoplight drags has been Jeep's 4.0-liter Cherokee. Ask ten Cherokee owners what they love about their ride and eight will say, "It's a fast mutha." The current 4.0-liter straight six makes 190 horsepower, enough to clock runs from 0 to 60 mph in 8.2 seconds. An impressive number for a four-by-four. Impressive, but not even close to outrageous."

XJ Saga said:

I would follow Dino's tips to make your XJ move with alacrity.

Click to expand...

Good idea. Then its performance will be close to outrageous (and the GMC Typhoon's).

http://www.angelfire.com/my/fan/SUV.htm
_________________________________
Dino's "Mean Green Machine"
1992 XJ Laredo 4-dr - 193k miles - 19k miles on 4.6L HO Stroker
AX15, NP231, D35c, D30

265hp@4900/325lbft@3500, 1/4 mile = [email protected], 0-60 = 5.6secs
Websites - Jeep 4.0 Performance, 4.6L Stroker Build-Up, Dino's Jeep Tricks

Forever in the s__t. It's only the depth that varies!

You know I just noticed the redline for the Typhoon-4800rpm! :rtm: :variety:

Dr. Dyno said:

You got that right. Here's the quote from the Car & Driver March 1992 issue when they road tested the GMC Typhoon (not the Syclone):

"Until now, the top gun in the sport-utility stoplight drags has been Jeep's 4.0-liter Cherokee. Ask ten Cherokee owners what they love about their ride and eight will say, "It's a fast mutha." The current 4.0-liter straight six makes 190 horsepower, enough to clock runs from 0 to 60 mph in 8.2 seconds. An impressive number for a four-by-four. Impressive, but not even close to outrageous."



Good idea. Then its performance will be close to outrageous (and the GMC Typhoon's).

http://www.angelfire.com/my/fan/SUV.htm
_________________________________
Dino's "Mean Green Machine"
1992 XJ Laredo 4-dr - 193k miles - 19k miles on 4.6L HO Stroker
AX15, NP231, D35c, D30

265hp@4900/325lbft@3500, 1/4 mile = [email protected], 0-60 = 5.6secs
Websites - Jeep 4.0 Performance, 4.6L Stroker Build-Up, Dino's Jeep Tricks

Forever in the s__t. It's only the depth that varies!

Click to expand...

XJ Saga said:

You know I just noticed the redline for the Typhoon-4800rpm! :rtm: :variety:

Click to expand...

Yeah, and my 4.6 stroker doesn't go much higher either, hitting the rev limiter at a too conservative 5150rpm even though it's still smooth and pulling hard at that point.
I'm sure GM underrated the Typhoon engine at 280hp. Performance numbers suggest the true output is more like 315hp and that's without winding up the turbo boost.

Dr. Dyno said:

Yeah, and my 4.6 stroker doesn't go much higher either, hitting the rev limiter at a too conservative 5150rpm even though it's still smooth and pulling hard at that point.
I'm sure GM underrated the Typhoon engine at 280hp. Performance numbers suggest the true output is more like 315hp and that's without winding up the turbo boost.

Click to expand...

Dino,
Off topic, found this article about CAI and thier dyno results. Quite interesting
http://mustang50magazine.com/techarticles/m5lp_0601w_cold_air_intake/

Looks like then new GT's are underated from the factory according to these dyno results?

DIMENSIONS AND CAPACITIES
Length............................................................ 170.3 in
Width.............................................................. 68.2 in
Height............................................................. 60.0 in
Wheelbase....................................................... 100.5 in
Track, F/R........................................................ 57.8/58.0
Clearance ........................................................ 7.1 in
Curb weight ..................................................... 3822 lb
Weight distribution, F/H ..................................... 56.8/43.2%
Capacity ......................................................... 20.0 gal
Oil capacity 4.5 qt

ENGINE
Type ........................................... turbocharged and intercooled V-6
Bore x stroke ................................ 4.00 x 3.48 in, 101 6 x 88.4mm
Displacement ................................ 262 cu in, 4300cc
Compression ratio .......................... 8.4.1
Engine-control system .................... GM with port fuel injection
Turbocharger ................................ Mitsubishi RH06
Waste gate .................................. Integral
Maximum boost pressure ................. 15.0 psi
Valve gear ................................... pushrods, hydraulic lifters
Valve gear ................................... pushrods, hydraulic lifters anti-roll bar
Power (SAC net) ........................... 280 bhp @ 4400 rpm
Torque (SAE net) .......................... 350 lb-ft @ 3600 rpm
Redline ........................................ 4800 rpm

DRIVETRAIN
Transmission .................... 4-speed automatic with lockup torque converter
Final-drive ratio ................ 3.73:1, limited slip
Transfer-gear ratio ............ 1.00:1

Gear Ratio Mph/1000 rpm Max. test speed

I 3.06 6.5 31 mph................ (4800 rpm)
II 1.63 12.2 59 mph................ (4800 rpm)
III 1.00 19.9 96 mph................ (4800 rpm)
IV 0.70 28.4 124 mph............... (4350 rpm)

WHEELS AND TIRES
Wheel size ................................................. 8.0 x 16 in
Wheel type ................................................ Cast aluminum
Firestone Firehawk SVX, P245/50VR-16 M+S
---------------------------------------------
Performance:

ACCELERATION
0 to 30 mph ............................................ 1.7
40 mph .................................................. 2.6
50 mph .................................................. 3.8
60 mph .................................................. 5.3
70 mph .................................................. 7.2
80 mph .................................................. 9.4
100 mph ................................................ 12.0
100 mph ................................................ 16.2
110 mph ................................................ 23.2
120 mph ................................................ 40.0

Top-gear passing time,
30-50 mph ............................... 2.9
50-70 mph ............................... 4.1

Street start,
5-60 mph ................................. 6.0

Standing 1/4-mile ...................... 14.1 sec @ 95mph
Top speed ................................ 124 mph

Weight is its biggest issue but as the stats say he may be able to take you off the line but after 60 MPH you will start catching up to him. The quarter miles times are proof enough that the weight of this thing is a huge factor. Any stroked, base model cherokee or commanche pre 1990 will take this thing out. On the drag, top speed and upper-end acceleration. So any of you that has a base stroked Jeep won't have to worry about this guy. As Jeeps get newer they get heavier also so anyone with late model and early 2000 Cherokees will need some serious power adders to stay with this thing.

XJ Saga said:

Dino,
Off topic, found this article about CAI and thier dyno results. Quite interesting
http://mustang50magazine.com/techarticles/m5lp_0601w_cold_air_intake/

Looks like then new GT's are underated from the factory according to these dyno results?

Click to expand...

Yeah, at 300hp/320lbft at the flywheel, they are indeed slightly underrated. The true figures should be more like 310hp/330lbft.