By Mike S. on Thursday, May 24, 2001 - 02:34 pm: Edit

Hi all,

Do you think the chip upgrade (I only know of one) will approximately compensate for going to 235/85 tires? In terms of power I think the Disco is already a bit weak on mountain highways and I don't want to lose any. I put ARB lockers front and rear and that was the time to change gears but I didn't. I don't want to open the pumpkins again if I can avoid it. What do you think? Do you know anything about the RPI chip or power loss with 235/85s you want to share?

Thanks,

Mike

PS. I never used crack and Kyle has been seen out of his backyard on occasion.

By JEEPETR on Thursday, May 24, 2001 - 02:47 pm: Edit

Hey Mike,

The Chip may make somewhat of an improvement, but its going to be marginal, and you are still going to "feel" those bigger tires. Keep in mind that those larger tires put the engine rpm's lower at every speed, which means its going to be further away from the power band. I doubt that a chip would lower the powerband and/or give you any appreciable increase in low end power/torque. Additionally you will feel the larger tires when taking off from a stop (if manual tranny), more clutch slip is required to take off smoothly and without stalling, no chip will remedy that. Gears are the way to go. Ashcroft 3.80's will put you just behind stock gearing with the 235/85's, and 4.11's just ahead. Save some money, and buy the gears, IMHO...

~Scott T.
'95 D-90 (JEEPETR)
'96 Disco (new addition to the addiction!)

By Ken on Thursday, May 24, 2001 - 03:00 pm: Edit

Just pick ~$4000 off your money tree from the backyard and stick a supercharger on your disco. Problem solved!

http://www.rimmersuperchargers.com/d-90.html

Ken
Money Tree died

By Ho Chung (Ho) on Thursday, May 24, 2001 - 03:04 pm: Edit

my vote goes to the 4.10 gears.

By Kyle Van Tassel (Kyle) on Thursday, May 24, 2001 - 03:30 pm: Edit

Yes Crack head , Ho is correct , gears are the only thing that will give you what you are looking for. They will help your Disco live a little longer as well.


Kyle

By Jon on Thursday, May 24, 2001 - 03:38 pm: Edit

...or get East Coast Rovers to build you one of their 340-horsepower Rover V8s LOL. (Hey, I wouldn't laugh too hard, that engine's a hot one)

By pjkbrit on Thursday, May 24, 2001 - 03:44 pm: Edit

I have the RPI chip on my 94 Disco...it's not bad but you have to sort ignition issues out first. I also did a Piper cam upgrade so my Disco is now good for about 220hp. It still lacks uphill torque however, but off the line pickup is greatly improved and gas milage is about 10% better...I wouldn't do the "wheels" but that's only my opinion. I think you'll lose a lot of power to the road and worsen your already sucky gas milage. The Supercharger idea sounds good, but it's gotta be spot on AND chipped or else you WILL burn valves, heads and all those other underfuel conditions NAS Rovers are known for. With the chip, I'd do the S'charger...but not for that price...$4000.00 my ass.
Pete

By Blue Gill (Bluegill) on Thursday, May 24, 2001 - 04:18 pm: Edit

I've discussed RPI twin-chip upgrad with Chris over at RPI - you're looking at about $1064 US (as of yesterday's conversion rates). That doesn't include shipping. You'll also be down for a few weeks since you have to send your ECU to RPI for re-programming.

In my opinion, chipping is kind of like cheating. I also associate chipping with an on-road, $70K Rangie with 18" handling package and sport tires (no offense, PKJBRIT - you've obviously done it right with the cam upgrade). I associate re-gearing with a Disco wearing 235/85 off-road tires and ARB lockers.

$1064 buys a lot of crack, and a lot of gears. How much exactly for the 4.10 gears?

By RVR OVR (Tom) on Thursday, May 24, 2001 - 04:22 pm: Edit

4.10's are tall bank. $800 for the just the gears, plus 100-300 for build kits, then installation as well.

By Kyle Van Tassel (Kyle) on Thursday, May 24, 2001 - 04:25 pm: Edit

Yes , you can do whatever you like to the engine but you still have a very screwed up transfer of power to the wheels. Going up in tire size killed the truck . To fix it right you must gear it acordingly. With the 4.10 you should end up with slightly more power then you had with the little tires. About 8%.Adding power just puts more stress on everything else in the chain , regearing relieves it...

Kyle

By Paul on Thursday, May 24, 2001 - 04:31 pm: Edit

Kyle and others, How was the 4:10 gears when climbing in the mountains of Colorado? Could you maintain a good speed(high) climbing to Eisenhower tunnel?

By Kyle Van Tassel (Kyle) on Thursday, May 24, 2001 - 04:36 pm: Edit

Yeah , you can maintain any speed you want pretty much. That altitude screws with my tired brain by the time we get there so I go pretty slow but typically my old tired truck with the 3.9 climbs the rockies in 3rd gear.

Kyle

By Ho Chung (Ho) on Thursday, May 24, 2001 - 04:38 pm: Edit

paul, 4.10 gears and 7.50 tires... not bad.
a whole lot better than the previous year with stock gears and 235/85

By Blue Gill (Bluegill) on Thursday, May 24, 2001 - 04:40 pm: Edit

$800+(100 to 300)=900 to 1100...install yourself and you have a hard, reliable, mechanical solution for the same price as a perceived electronic "solution"...

By Kyle Van Tassel (Kyle) on Thursday, May 24, 2001 - 04:46 pm: Edit

LOL , Ho dont know about the Rockies , we cant get him on this side!!!

Kyle

By Frank on Thursday, May 24, 2001 - 04:48 pm: Edit

Let me ask you guys this: What would the 4.10 gears do to a disco with stock tires? Would it improve perceived power or not? Would it help with towing? What about on the hwy?

By Kyle Van Tassel (Kyle) on Thursday, May 24, 2001 - 04:51 pm: Edit

Ouch! On a Disco with stock tires you would have a shit load of power. Yes , it would help allot with towing as well. Down side is that you would take a serious hit in mileage and the poor bastard would be turning up pretty hard at highway speeds.

Kyle

By wesley on Thursday, May 24, 2001 - 04:54 pm: Edit

How difficult is it for a novice DIY to put in arb lockers and change the gearing?

By Ron on Thursday, May 24, 2001 - 05:05 pm: Edit

It is tough. I am currently confused as hell. But since it is my spare dif and I have time on my side I think I can hack it.

Ron

d-90.com has a write up and also my standard answer is

It is easy to install it is hard to install right

By Parker Garrett (Parker) on Thursday, May 24, 2001 - 05:11 pm: Edit

It's as easy as calling your trusted mechanic to do it for you. If you've never seen the inside of a diff and done some work in there, you shouldn't even think of doing such a task. (IMHO)

By Ron on Thursday, May 24, 2001 - 05:16 pm: Edit

Ya ya ya. Based on the ARB installs I have seen I will take my chances.

Ron

By Axel Haakonsen (Axel) on Thursday, May 24, 2001 - 05:21 pm: Edit

As long as you get the backlash right, you should be ok. Otherwise, you'll be eating those gears up in no time.

By Ron on Thursday, May 24, 2001 - 05:24 pm: Edit

what about the o rings? I thought that was the major issue on rover ARBs. pssssssssttt open dif type problems anyway.

Ron

By Blue Gill (Bluegill) on Thursday, May 24, 2001 - 05:26 pm: Edit

Parker - you gotta start somewhere, and the only way to start is to open the sucker up and hope there are no pieces left over when you put it back together.

By Ron on Thursday, May 24, 2001 - 05:29 pm: Edit

"Parker - you gotta start somewhere, and the only way to start is to open the sucker up and hope there are no pieces left over when you put it back together."

Ya I always say the only difference between a trained monkey and me is the training.

Ron

By Parker Garrett (Parker) on Thursday, May 24, 2001 - 05:30 pm: Edit

Definitely be very careful with the infamous "O" rings. They can make your day a drag. Infact, I would recommend replacing them every so often (you can usually get them for free from ARB if you run into a rep) so you do not get "psssssst" problems on the trails.

By Parker Garrett (Parker) on Thursday, May 24, 2001 - 05:35 pm: Edit

>>>"Parker - you gotta start somewhere, and the only way to start is to open the sucker up and hope there are no pieces left over when you put it back together."


I totally agree with you here but I learned the hard way. KAABOOOM!! It's not fun. If I was to do it over again I would have spent some saturdays down at the local shop watching and learning and even helping if they would let me.

By pk on Thursday, May 24, 2001 - 05:44 pm: Edit

Beware....

Setting the lash thing (that is what is on d-90.com).

Changing ring and pinion is a whole different ball of wax. You have to set up the pinion height first. How you going to do that? Then you have to mesh the gears for the proper contact pattern. You can probably do that with some frustrating effort and a bunch of Prusian Blue.

Then, finally, you have to set up the lash and that part is easy, just follow the pictures on d-90.com.

pk

By Blue Gill (Bluegill) on Thursday, May 24, 2001 - 05:53 pm: Edit

Parker - In retrospect I see that when you said "such a task" you meant don't go in cold and attempt to do ARB and gearing...that makes sense, and that's why I'm getting ready to do a casual "take it apart to see how it works" with a little ARB inspection as long as I'm in there.

By Kyle Van Tassel (Kyle) on Thursday, May 24, 2001 - 05:54 pm: Edit

Locker is no biggie. Locker and gears? Thats a biggie. I desroyed plenty of sets in my time during the learning. Actually PK. Its all together in one shot. You set backlash and depth by the pattern. WHen the pattern is right ,both of those are right...
Kyle

By Kyle Van Tassel (Kyle) on Thursday, May 24, 2001 - 05:59 pm: Edit

LOL , "ARB inspection". Man , throw that shit in the trash and get a real locker... Then you dont need no more "Inspections" and you have no worry of blowing bubbles when you reach for that button in a mud hole...

Kyle

By Parker Garrett (Parker) on Thursday, May 24, 2001 - 06:07 pm: Edit

>>>"LOL , "ARB inspection". Man , throw that shit in the trash and get a real locker..."


What's a real locker? Let me guess, a True-Trac right? HA!

By Blue Gill (Bluegill) on Thursday, May 24, 2001 - 06:07 pm: Edit

Hey Kyle, mind if I dig through YOUR trash? Sounds like there is apt to be some good shit in there...

By Kyle Van Tassel (Kyle) on Thursday, May 24, 2001 - 06:09 pm: Edit

LOL

By Kyle Van Tassel (Kyle) on Thursday, May 24, 2001 - 06:10 pm: Edit

Actually the ARB is an air spool. Detroit set the standard of what a locker is I believe...

Kyle

By Blue Gill (Bluegill) on Thursday, May 24, 2001 - 06:11 pm: Edit

what the hell is LOL? Lots Of Luck?

By Parker Garrett (Parker) on Thursday, May 24, 2001 - 06:14 pm: Edit

>>>"Actually the ARB is an air spool. Detroit set the standard of what a locker is I believe... "

That still leaves a TT as a "Limited-slip" Hmmm, no locking going on there.

By Ho Chung (Ho) on Thursday, May 24, 2001 - 06:56 pm: Edit

so we talking about lockers again?
LOL

By Kevin Shaw on Thursday, May 24, 2001 - 08:13 pm: Edit

There is always the option of Xfer gase gearing to rather than the changing the R&P. There are 4 different gearsets available for the LT230 xfer case. Changing the high gears from 1.22 to a 1.4 set would give the same sort of change as fitting 4.1 gears in the diffs. Theres always the 1.66 set for those needing more.

These gearsets are imported from the UK to Australia and retail for $1000 australian or about $550 US. You could probably import them yourself cheaper, direct from someone like ashcrofts, see http://www.autoconv.com/ Another option muight be to install a defender xfer case which will already have the 1.4 ratio in it.

Just a bit of food for thought.

Kevin

By Kyle Van Tassel (Kyle) on Thursday, May 24, 2001 - 08:35 pm: Edit

THen you open a whole can Kevin. You then lengthen the chain of parts that will be affected by more torque...

Kyle

By Mike S. on Friday, May 25, 2001 - 12:39 am: Edit

Thanks for all the info. I will "skip the chip" for now and take a good look at 4:10 gears. Wish I put in gears when I did the lockers!

By John C. on Friday, May 25, 2001 - 09:34 am: Edit

Question:

Couldn't you get the gears and lockers installed by someone like GB and have them send it to you and all you would have to do is install the third member? Excuse my ignorance but I thought this is what Abraham did for his Disco. He fried the gears in his rear diff, we pulled out the 3rd member and sent it to Bill. A few days later Bill sent him the 3rd member with the lockers. Couldn't Bill have installed the gears while he was at it?

John C.

By Kyle Van Tassel (Kyle) on Friday, May 25, 2001 - 09:37 am: Edit

Yeah John he will do that. If you dont have a local shop that you trust and you cant do it yourself , thats the best way to go...

Kyle