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View Full Version : Getting more power out of a KH Xi...



MYKHVERADA
10-02-2012, 07:43 PM
Hey guys,

well I have a 2000 Verada Xi with 128,000KM on it. Its got quite nice power but after 5,500 RPM it kind of just falls flat. I've got $1K, maybe $2K tops, and wanting to get a little more power out of it. Its got a standard 4 speed auto. Are the 5 speed autos much better? I've read up a bit on 380/Ralliart cams. Worthwhile? The engine is entirely stock.

Cheers.

TiMi
10-02-2012, 07:45 PM
manual conversion

MYKHVERADA
10-02-2012, 07:48 PM
P1 NSW auto only license.

manual conversion

Red Valdez
10-02-2012, 07:55 PM
I believe the Ralliart/380 cams give the engine a bit more of a push up to redline. If you want to eliminate the 'dead' feeling after 5500rpm I would definitely look at them.

Changing your rear muffler is the best bang-for-buck mod on any Magna or Verada that doesn't have one (ie sports models).

MYKHVERADA
10-02-2012, 08:15 PM
When I was searching before, I read that DOHC heads off a Pajero can be put onto my SOHC 3.5? Possible....? What would be needed, part wise other than the head?

dreggzy
10-02-2012, 08:17 PM
I believe the Ralliart/380 cams give the engine a bit more of a push up to redline. If you want to eliminate the 'dead' feeling after 5500rpm I would definitely look at them.

Changing your rear muffler is the best bang-for-buck mod on any Magna or Verada that doesn't have one (ie sports models).

Agreed. You could take it even further by doing the front muffler and headers. For example I am getting my rear muffler done soon using the very popular lukey model (the model number has escaped me) then taking the mid section from a vr-x or sports, whichever I can find, then putting in a 200cpi catalyctic converter and eventually headers as well. That would be worth a good 10kw at least.

mcs_xi
10-02-2012, 08:21 PM
Soon, I am doing the exhaust mod (HM headers, 200CPI cat, Sports rear muffler) to my KH XI. I Also installed tippy with a KJ ECU. That made a small difference to the way it drove, as the ECU is much clevererererer.

I will let you know how the Zorst mods make a difference.

Mike

Skapper
10-02-2012, 08:50 PM
I'd have thought an exhaust upgrade - front to back - and an ECU tune would cover your needs nicely. On that budget ($2000).

After that start shaking the weight. With the exhaust upgrade you're already on your way - shook 14kg off my Veradas are heavy with all their "luxuries".

And, probably a better start would be better handling and brakes. Any extra power will be difficult to utilize safely with the suspension/tyres/brakes in standard trim. Maybe spend the $2k on struts, springs, better rubber and a rear sway bar.

MadMax
10-02-2012, 08:58 PM
I'd have thought an exhaust upgrade - front to back - and an ECU tune would cover your needs nicely. On that budget ($2000).

After that start shaking the weight. With the exhaust upgrade you're already on your way - shook 14kg off my Veradas are heavy with all their "luxuries".

And, probably a better start would be better handling and brakes. Any extra power will be difficult to utilize safely with the suspension/tyres/brakes in standard trim. Maybe spend the $2k on struts, springs, better rubber and a rear sway bar.


You have just spent the money twice! lol

Skapper
10-02-2012, 09:20 PM
Well... yeah... of course. It's a car, that's how it works. :P

But seriously, choose one was what I meant to say. On that budget anyway.

Wiggles
10-02-2012, 09:24 PM
SKR tune, lukey rear muffler, upgrade to a 2 1/4 inch exhaust from a sports model, extractors.

Cat helps but for cost vs gain its not really needed

epitrochoid
11-02-2012, 06:40 AM
start with a 2.5" cat back exhaust with a free flow muffler and resonator. This may keep you happy, but if you want more you could go with extractors and a high flow cat.
Then i would look at cams and a ECU tune (the tune will require you to use premium fuel).
This way after you do the exhaust you will get the most benefits from the other mods if you do them.
I put a redback 2.5" cat back exhaust on my TJ2 V6 and it pulls really well up to redline now. It cost me $450 for the exhaust off ebay and $50 for an exhaust shop to modify it to fit as the cat on my car (factory) was too long and the centre pipe had to be shortened.

REgards
Epitrochoid

MYKHVERADA
11-02-2012, 07:19 AM
Ok so sounds like a Lukey exhaust is the way to go. Rough guess at how much these are?

Wiggles
11-02-2012, 07:37 AM
225 i think I paid. That was for the bolt on for the tj2 exhaust

Skapper
11-02-2012, 02:27 PM
Lukey rear, bolt on; I paid $240 delivered. Shop around.

You could chase up the rear muffler of a sports or a VRX, but the Lukey is 3kg lighter. In a Verada every kg you can shed (safely) is a bonus.

spud100
11-02-2012, 03:34 PM
Done properly a new exhaust system makes a decent difference.

Extractors, 2.5" mandrel bend system with a suitable muffler, look at the Magnaflow ones. Keep as big a resonator as possible. as well as a decent 2'5" metal 200 cpi cat.

Then consider cams and a SKR tune. You can get close with a postal one.

Gerry

cooperplace
11-02-2012, 11:20 PM
.

Changing your rear muffler is the best bang-for-buck mod on any Magna or Verada that doesn't have one (ie sports models).

Hi Red, would changing the rear muffler add power in a standard TW 4sp auto? And if so , what effect does it have on noise and fuel economy?

thanks

Red Valdez
13-02-2012, 08:32 AM
The only difference between the late-model base models and sports models was the rear muffler. 8kw and 1nm was the difference I believe. Will make it noisier, but the stock VR-X exhaust is good - has a nice note on acceleration but doesn't drone.

AaronoTG
13-02-2012, 08:39 AM
Ok so sounds like a Lukey exhaust is the way to go. Rough guess at how much these are?
There are a few that are for sale here from time to time (albeit second hand), but they sell for a lot cheaper and you're buying it from a fellow AMC member.
So keep an eye out for one in the fs thread too :)

But there again you might want a brand new one.

380Mitsu
13-02-2012, 09:42 AM
Hi Red, would changing the rear muffler add power in a standard TW 4sp auto? And if so , what effect does it have on noise and fuel economy?

thanks

From a 4spd auto owner running a higher flowing rear muffler comparable in size / sound to the factory sports one, fuel economy is slightly better (maybe .5L/100km better) and it is a little louder than the std non-sports muffler, mainly under load. You do get a more pronounced drone around 2,000-2,400rpm.

kurt
16-02-2012, 09:59 AM
To be honest. I reckon modding the 4sp auto is the wortest modding combo with engine and trans. I put 380cams in my misses 4sp auto KF verada yeh it did make a nice little gain but nothing much over stock. But when putting the 380 cams on my 5sp manual sports magna wow the gain was much better. I just reckon the 4sp auto wont give u much in the way of power and mods you will get some power but nothing to much.

Skapper
16-02-2012, 05:00 PM
I reckon modding the 4sp auto is the wortest modding combo with engine and trans

I half agree. Manual will always be the better option, no argument there. But, while the 4 speed isn't "the best" its not that bad. Sure the first gear is a bit tall, and the shift into 2nd isn't conducive for break neck acceleration, but the tran's itself (outside of wave springs) is still capable. I've driven both the five speed auto and the four speed auto and I can row the four speed along well enough to keep up with other cars. Getting the four speed off the line quickly isn't so hard either if you stall it up. I've posted 0-100 times on the forums here and my four speed exec was faster than my 5 speed auto GTVi.

Its like anything you cant change (easily) you just learn to work around the shortfalls. One way of "working around" the four speed is to do a manual conversion. The other is to develop techniques to better utilise the transmission.

HaydenVRX
16-02-2012, 05:49 PM
How long until you are on your next stage of p's? Manual conversion needs planning, could take a month or so.

MYKHVERADA
16-02-2012, 08:53 PM
Sorry guys! There'll be no manual conversion for me because:
A) I'm way too lazy for that thing.
B) My car is a city car.
C) I'm horrible at driving manual. I'm possibly the roughest driver in manual ever!


How long until you are on your next stage of p's? Manual conversion needs planning, could take a month or so.