View Full Version : Wanted: Opinions, facts and educated guesses!!!
Dustbowl
14-11-2012, 01:29 PM
So you want more power.... It's a problem for many of us...
If your XJ is the offroad monster it was born to be yet is a highway slug, this thread is for you, join ol Dusty (dodgy dan) as we discuss and explore the possible options to give your xj the umpf it was dreamed to have!
Out current test subject- 1998 XJ Cherokee sport 4.0, 220,000 on the clock.
My current ideas are-
naturally aspirated high worked 4.0 (easier option)
An eaton super charger on our 4.0
Or (the beast) a cummins 6bt (which I have been offered for quite a good price)
(is this possible??)
Other options to be may include an AMC 360, a 302 Cleveland or a 4.7 powertech.
Cypher
14-11-2012, 01:44 PM
From limited reading what I've found is that the factory computer setup is very unfriendly to anything but mild performance mods eg exhaust, injectors, etc
I am interested in what options there are however
anthonygubbin
14-11-2012, 01:58 PM
I have heard the same as Cyhper on the update models. I too would be interested in what I can do though. Eventual plan is extractors, 99-00 intake mainfold, modded LPG throttle body inlet, bored TB, and decent exhaust system. I have considerd a head upgrade for about $800 (Melbourne bloke), which would be port polished and larger valves. However doing all this requires a re-map of the ECU as far as I am aware, to actually see any benefit of the mods. Remap and Dyno tune = about $1200-$1300, (Aust Performance Tuning).
Regards A
junglejuice
14-11-2012, 02:18 PM
From what I have read and experimented with on mine I have found that the late model intake mod works well, so does the Throttle Body spacer and extractors with larger free flowing exhaust.
I have to add a caveat, mine is a pre-update OBD1 and from everything I have read the OBD1 ECU is more tollerant of mods when compared to the OBD2.
The next thing on my list is bigger 4 pin injectors with an aftermarket rising rate FPR (Fuel Pressure Regulator) to make the most of the new injectors.
If you're running bigger tyres one of the best things for performance and economy is to regear the diffs to suit the tyres and from my experience aim for the final drive ratio of a Limited instead of a Sport.
The better option IMHO if more grunt is required is to go a stroker, keeps everything looking stock which keeps the boys in blue away, everything is an easy fit as it is all stock and very few mods apart from the ECU upgrade and exhaust etc is required.
What I have also found is that some Xj's just go better then others, I have driven one recently that as far as I can tell is stock apart from the 95 intake tube, but goes like a scalded cat!!!!
anthonygubbin
14-11-2012, 02:26 PM
Hey JJ I have 4.11s on the front and soon on the rear. Eventual plan is to get 31s. What would my gearing be like then? Would it be the same or lower than my 235/75s?
Regards A
junglejuice
14-11-2012, 02:47 PM
AG, I run 3.73:1 gears in mine which are the right ratio when compared to a stock Sport, the numbers below are all rpm @ 100kph
A stock Sport will do approx 1965
A stock Limited will do approx 2028
A Sport on 235/75/15's will be approx 1924
With 30's on mine being 3.73's mine is approx 1983
Yours with 31's on 4.11's will be approx 2095
So it should be good with that ratio, it will be better offroad and better for towing and shouldn't be too bad on fuel, this is based on the fact that mine gets better economy now it has been regeared then it did when stock geared even on the stock size tyres....
Hamsteh
14-11-2012, 04:01 PM
Or (the beast) a cummins 6bt (which I have been offered for quite a good price)
(is this possible??)
Other options to be may include an AMC 360, a 302 Cleveland or a 4.7 powertech.
As far as I am aware the 6bt is just too large, there are a couple 4bt XJ's (and an MJ I believe) floating around pirate4x4 and youtube.
I'd kill for the 6bt though haha, I work with Cummins occasionally and they're just a lovely engine!
Dustbowl
14-11-2012, 04:29 PM
As far as I am aware the 6bt is just too large, there are a couple 4bt XJ's (and an MJ I believe) floating around pirate4x4 and youtube.
I'd kill for the 6bt though haha, I work with Cummins occasionally and they're just a lovely engine!
They are, I'd love a 3.5 Eco boost or a 7.3 power stroke, but the Eco boost are far too deer and rare and the power stroke soo heavy! And they fit snug in an F250 engine bay, so the poor jeep has no chance :p
So there I am back to the 6bt which is huge... But it's not an impossible job, as long as it fits between the guards I'll run patrol springs and no bonnet if I have to! :p
JJ that info was awesome!! You are right, some feel like 150 hp and others feel 250!!
I think I might start out like you and AG suggested, there is a lot that can be done to improve power just being naturally aspirated :)
junglejuice
14-11-2012, 04:58 PM
I have a late model intake here complete with throttle body and injectors etc that I could send down with the towbar if you're interested.
I can also organise you a Junglejuice fab throttle body spacer as well if you want...
Dustbowl
14-11-2012, 05:02 PM
I have a late model intake here complete with throttle body and injectors etc that I could send down with the towbar if you're interested.
I can also organise you a Junglejuice fab throttle body spacer as well if you want...
Oooooh that sounds too good, is it the full width TB?
And what makes a spacer work like they are claimed to?
junglejuice
14-11-2012, 05:10 PM
What do you mean by "full width TB"?
The extra volume and runner length of the intake manifold....
Dustbowl
14-11-2012, 05:17 PM
What do you mean by "full width TB"?
The extra volume and runner length of the intake manifold....
Oh, riiiight, makes sense now :p
Some throttle bodies are the full width of the manifold opening (62mm i think?) some ( like mine) are restrictive to a degreeand don't let as much air in
junglejuice
14-11-2012, 08:16 PM
I can machine the bottom lip out if you want, I have done mine but I don't reckon it made any real difference, mine is still the stock size though through the rest of the TB....
Dustbowl
14-11-2012, 08:22 PM
Thought you had gone to work on me buddy :p
So keeping my existing TB won't be a bad idea, unless yours is better :p
Did you mean a better intake manifold or exhaust manifold?
Wooders
14-11-2012, 08:58 PM
Just do this (http://www.jpmagazine.com/featuredvehicles/154_1001_1986_jeep_cherokee_xj/viewall.html)
Windex
14-11-2012, 10:32 PM
Just do this (http://www.jpmagazine.com/featuredvehicles/154_1001_1986_jeep_cherokee_xj/viewall.html)
I love it!
However I really think the only viable option for getting more power and keeping the costs under 10k is to go down the stroker path. This is what I think I will do once I sort out all the other issues that my car has.
Dustbowl
15-11-2012, 07:16 AM
Wooders, very cool, but it's a tad excessive (Just a little!!), no engineer would even look at it :p
Windex, I know what you are getting at, but surely an extra 80-150 hp from a supercharger would be cheaper and also improve fuel economy :mrgreen:
rainman
15-11-2012, 09:36 AM
Last I looked supercharger kits were $ 5000.
That what you are talking about? Or we're you going to go another way?
Cypher
15-11-2012, 10:35 AM
Hmmm on my phone at the moment so hard to look up info...what kind of boost do the supercharger kits run? Do they require ecu modification?
Wooders
15-11-2012, 11:00 AM
Wooders, very cool, but it's a tad excessive (Just a little!!), no engineer would even look at it :p
You might be surprised at what you can get passed sometimes.
junglejuice
15-11-2012, 02:03 PM
That V8 one even has cruise control....
junglejuice
15-11-2012, 02:06 PM
Thought you had gone to work on me buddy :p
So keeping my existing TB won't be a bad idea, unless yours is better :p
Did you mean a better intake manifold or exhaust manifold?
What I was offering is a better intake manifold, extractors will also help as I mentioned there somewhere as well...
anthonygubbin
15-11-2012, 02:21 PM
What I was offering is a better intake manifold, extractors will also help as I mentioned there somewhere as well...
If it does not sell let me know JJ, I am looking for a 99-00 intake manifold if the price is right. I don't need a spacer though as I have an LPG intake ring on top and the spacer won't fit.
junglejuice
15-11-2012, 03:17 PM
What is the right price for you AG?
Just curious, what is the benefit of a TB spacer? I've heard putting on early pre-updates an help due to the manifold design but what about a post-update/ 99+? Any benefit there?
What's the theory/ mechanics? underlying this mod?
Is it like a hiclone? which I understand to be snake oil.
Dustbowl
16-11-2012, 04:37 AM
Just curious, what is the benefit of a TB spacer? I've heard putting on early pre-updates an help due to the manifold design but what about a post-update/ 99+? Any benefit there?
What's the theory/ mechanics? underlying this mod?
Is it like a hiclone? which I understand to be snake oil.
Haha it is different, the spacer increases the effective volume inside the manifold, plus it allows the air to travel in a single constand velocity (direction and speed) for a bit longer (Venturi effect works against you if you have a lit of buckles and turns), strange but allegedly you can feel the difference :0= ;)
junglejuice
16-11-2012, 06:18 AM
I have had numerous people tell me that the TBS makes no difference and cannot work so as an experiment one day I was in the garage so I removed the TBS before my wife went shopping, she drives the Xj most days and is very familiar with it, when she got hoe she informed me that there was something wrong with the brakes that I need to fix as they must be stuck on as it wasn't as peppy as per normal, I said OK.
Later the same day she had to go out again and upon returning home said that it was all better again...
The only thing I did was to remove and then refit the TBS.....
Or this one
http://www.jpmagazine.com/eventcoverage/154_0611_jeep_hill_climb_event/photo_07.html
Ok, so an increase in the manifold size would make it a little more reponsive as it can get the air into the engine quicker on an increase in throttle, that makes sense.
I would think that this would be offset by the restrictive effect of a snorkel no?
I have a safari one on mine and the maybe 30mm dia flexi pipe that takes a rather bendy path to the front of the airbox would cause a fair amount of restriction. I"m guessing a TBS would only have an effect once all the other restictions were sorted out eh?
I was reading a performance tuning guide in some 4WD mag and they reckon they look at snorkles before fiddling with manifolds/ internals.
I'm guessing on a standard airbox config it would make a difference.
(I'm following this thread with a view to opening up mine, 99, a little as I think it's just not breathing properly. Considering a TBS as I have to swapout the current TB anyways, I've already got rid of the big plastic box with an early model intake pipe.)
junglejuice
16-11-2012, 03:09 PM
The Safari style snorkels are restrictive especially when compared to the Airflow units like mine which has a much shorter hose which is around 70mm in diameter!!!
The Safari style snorkels are restrictive especially when compared to the Airflow units like mine which has a much shorter hose which is around 70mm in diameter!!!
Where does the hose route? I take it it's a much bigger hole in the inner arch? I might have to hack mine now that I removed the heat exchanger that was in the way of the new routing I wanna use.
junglejuice
16-11-2012, 07:14 PM
Where does the hose route? I take it it's a much bigger hole in the inner arch? I might have to hack mine now that I removed the heat exchanger that was in the way of the new routing I wanna use.
Here you go....
http://i1182.photobucket.com/albums/x451/junglejuice72/4wd%20Action%20Photoshoot/IMG_1044_resize.jpg
Raisins78
16-11-2012, 08:42 PM
Mopar 4.7 stroker long motor $3500 from the US.
Mopar injectors to suit the stroker (They have a set of injectors that can be used with the factory tune. Supposed to work really well.
As JJ stated, keeps the police happy and unaware. Plus its built by Mopar...so you can bring that up in shed conversations etc lol...
junglejuice
17-11-2012, 06:22 AM
Mopar 4.7 stroker long motor $3500 from the US.
Mopar injectors to suit the stroker (They have a set of injectors that can be used with the factory tune. Supposed to work really well.
As JJ stated, keeps the police happy and unaware. Plus its built by Mopar...so you can bring that up in shed conversations etc lol...
Having driven a stroker, using one that doesn't require an aftermarket ECU would mean better reliability, ease of installation and oooh so much fun!!!!!!
Definitely would want to ditch the d35 though....
Raisins78
17-11-2012, 10:09 AM
Having driven a stroker, using one that doesn't require an aftermarket ECU would mean better reliability, ease of installation and oooh so much fun!!!!!!
Definitely would want to ditch the d35 though....
Id have to send the D35 out in a blaze of fury lol....then swap it for a 8.25
anthonygubbin
13-12-2012, 07:07 PM
So apart from a 3.5k + stroker is there any cheaper options to get a little more oomph particularly on LPG? I have explored a different intake but the LPG (TB style) needs a special intake to create the ventury effect. So that rules out me making a new wider one. I was told that a better system will make a marginal difference as will match porting. Am thinking of upgrading the system and adding extractors; opinions sought of that one please.
The ECU mod is too expensive as a stroker can be installed for the same price. I am thinking of gettting a head ported & polished by that bloke in Melbourne. In regards to that will I need a 98 head? As the plan was to pull one off a wreck and get for next to nics but getting a OBD2 head if that is what is needed might work out a little expensive.
Regards A
AG, suggestion if you are using LPG you can actually run an older engine as it will meet newer emissions.
So why not consider puting an older 5.0 or 5.7 V8 and building it to run on straight LPG. Ie do away with a lot of the troublesome electron conversions.
Nitrous oxide injection? ;-)
anthonygubbin
14-12-2012, 06:45 PM
AG, suggestion if you are using LPG you can actually run an older engine as it will meet newer emissions.
So why not consider puting an older 5.0 or 5.7 V8 and building it to run on straight LPG. Ie do away with a lot of the troublesome electron conversions.
I am not really wanting to go down the line of an engine transplant. I would prefer to stick with what I have, even if it is limited. As for designated gas I can't carry enough fuel for long trips unless I carry petrol as well. When I was in Tassie I trecked down the East Coast and ran out of gas because I could not get it after I left St Helens until I got to 30mins out of Hobart.
Regards A
Raisins78
16-12-2012, 04:29 PM
So apart from a 3.5k + stroker is there any cheaper options to get a little more oomph particularly on LPG? I have explored a different intake but the LPG (TB style) needs a special intake to create the ventury effect. So that rules out me making a new wider one. I was told that a better system will make a marginal difference as will match porting. Am thinking of upgrading the system and adding extractors; opinions sought of that one please.
The ECU mod is too expensive as a stroker can be installed for the same price. I am thinking of gettting a head ported & polished by that bloke in Melbourne. In regards to that will I need a 98 head? As the plan was to pull one off a wreck and get for next to nics but getting a OBD2 head if that is what is needed might work out a little expensive.
Regards A
The LPG venturi is what robs you of power the most, even in petrol mode.
You can upgrade your current system to gas injection (liquid injection is not available yet i dont think)
This way you will keep half your LPG system inc the tank, and just have the venturi and mixer replaced with injectors into your manifold.
Ring a good LPG shop and ask the question.
I would estimate around $2000.
The LPG gas injection systems get near stock petrol power levels, with no restrictions in the intake pipe run....
Just checked google...and this is the first result (liquid injection)
http://www.australianlpgwarehouse.com.au/Products/Systems/JTG-Liquid-Injection.aspx
layback40
16-12-2012, 07:09 PM
The LPG venturi is what robs you of power the most, even in petrol mode.
You can upgrade your current system to gas injection (liquid injection is not available yet i dont think)
This way you will keep half your LPG system inc the tank, and just have the venturi and mixer replaced with injectors into your manifold.
Ring a good LPG shop and ask the question.
I would estimate around $2000.
The LPG gas injection systems get near stock petrol power levels, with no restrictions in the intake pipe run....
Just checked google...and this is the first result (liquid injection)
http://www.australianlpgwarehouse.com.au/Products/Systems/JTG-Liquid-Injection.aspx
Dont know much about LPG systems.
Can some one please explain why you cant set up the injection system so that you can use the fuel injectors for either petrol or LPG.
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