Top end speed / pickup

[mooxie]

Hi all, picked up an 04 ZD30 D22 a couple weeks ago and I'm just starting to get her ready for play!
One thing I have noticed is that top end speed and pickup is a bit lower than I'd like.
She sits on around 2850rpm at 110km/h but need a good run up to overtake. I'm happy with the low end pickup but would like to improve highway driving and overtaking due to my rural location.
Planning an off road trip in the Australian alps at the moment - but it's almost 1000km each way of highway driving to get there!
Yes I am a Navara noob, but have been doing some thorough forum reading! Just changed the air, oil and fuel filters plus the EGR and butterfly mods. Will be adding a catch can and snorkel in the next week or so.
Exhaust is probably next on my list, which I know will help her breathe and give a bit better turbo spool up.
Does anyone have any suggestions to improve top end speed and pickup?

 

[Old.Tony]

Welcome to the forum.

The largest power gain you'll get is from a chip. Intercoolers will give you a few percent, exhaust a couple percent (maybe), EGR a couple percent - but chips can give a much mor substantial boost. Visit ChipIt and Northside 4x4 to learn about the BEST chips. You can go simple (and cheap) with a No-Limits chip but these just make the fuel pump run harder.

If you want an EXCELLENT resource for comparing different chips and what they do, then have a read of this thread by Northside 4x4.

 

[mooxie]

Cheers Old Tony!
That's a massive thread!
I was under the impression that while a chip will give the most substantial boost, they're best fitted after adding and exhaust and possibly intercooler? Especially if I get a decent chip, which would be mapped to my mods?
Would be keen to know how other people have gone adding a chip to a stock Nav!
Anyone end up with a bit lower idle and better pickup on the highway after adding a chip?

 

[180degrees]

They are all the same apparently, the 3.0L that is, 2.5 has pretty good pickup around that region, I guess you could start with the EGR mod and swirl control mod, intercooler is really only to stop the turbo killing your motor...

 

[nakedape]

Put that intercooler on it before you do anything else - the top end pick up will be more than disappointing with a turbo fan in the head lol.

 

[Craig09]

Mines a single cab o4 and when I did the Egr and the 80 series airbox she could breathe so much better,I only did the airbox for dual battery and was scePtical of any gains in peformance but there was a very noticeable difference.ive gone from 3100rpm at 100-110 to 2600rpm.thats with steel tray and 32s.still be a bit of a run up (to be expected when she comes in at 2600-2800kg)to overtake but nowhere near what I did before,it's quet responsive up high now.

 

[ben85]

ive gone from 3100rpm at 100-110 to 2600rpm.thats with steel tray and 32s.

hey craig, i'm not being a smart ass mate but theres no way your revs could have changed like that.
your driving a manual so in each gear your revs will be relative to your speed.
the air box mod may allow you to increase speed faster or more efficiently but your revs will still be the same..

if your getting your speed from your gps, your revs may appear to be different at a certain speed if you have changed tyres as you have effectively changed the final drive ratio.

 

[180degrees]

mm its impossible for the rpm of the motor relative to the speed to change like that.

 

[Craig09]

well f@#$%d if i know but i changed nothing,already had the tyres on so even if the spedo is out a little its still the same as it was before the airbox.i just know that it was running at 3000-3100 and after the airbox its at 2600-2700.

 

[Craig09]

i cant think what else could of possibly done it but im happy,saves a good bit of fuel in the long run.
i dont understand what you mean by its not possible for rpm to change in relation to speed,if the engines working harder at the same speed the rpm will be higher wont it

 

[nakedape]

i dont understand what you mean by its not possible for rpm to change in relation to speed,if the engines working harder at the same speed the rpm will be higher

Not always, consider - cruising unladen @ 100kph v towing two tonnes @ 100kph. The drive train is fixed (assuming the same gear etc) hence the revs are the same for the same speed, but to move the larger mass at the same speed more energy is required = more fuel being pumped in to create a bigger bang = more energy for each bang. Or some shit like that, isn't it!

 

[Craig09]

yea so to use towing as an eg,if i cruize at 10kph with nothing then hook 2 tones on the back and go 10kph im going to need more revs to move the extra weight

 

[Dion]

Only in an automatic. In a manual the relationship between engine and road speed is fixed in a given gear. At a fixed RPM an engine can be at a varying degree of load, which influences fuel consumption.

 

[Craig09]

well if someone can explain my revs dropping ill be glad to hear it coz im pretty sure i can read the dash right lol.
either way less revs less fuel im happy

 

[slugger]

Either your clutch was slipping or you have put on larger diameter tyres.

 

[Craig09]

nah mate,it was running at 3100 then when my airbox came in the mail i did the mod then it was running at 2600.i didnt change anything else.so if it was clutch it wouldnt just stop slipping when i put the airbox in (and it was brand new) and the tyres have been on it for months before the mod.
if i wasnt so flat out id stick the old one back in take a vid then the 80 series take a vid and post them up

 

[slugger]

Dunno then, maybe your speed or tach had some intermittent fault. Changing the airbox just doesn't make sense to me.

 

[Craig09]

meh shes running good now haha.
the amount of peformance gain i got from the mod putting revs aside was awsome,deffently worth doing.responce has gone through the roof

 

[Old.Tony]

It's a very odd thing to happen.

In a manual with the clutch pedal released (and assuming a properly-working clutch) one revolution of the engine becomes one revolution of the gearbox input shaft. This then causes the final output to turn a fix number of times and that turns the diff and axles. 10 revolutions of the engine turns everything 10 times as much etc etc.

When we're talking speed, every revolution of the engine translates to a number of revolutions of the rear wheels. If you change the wheel size UP, every revolution of those wheels takes the car a little further.

That's why people are so confused by the airbox change causing this. The drive train is a fixed thing, it changes when you change gears but those gear ratios are static for the life of your car (with that gearbox & diff). Changes can happen with tyre change but to change a few hundred RPM like you've experienced, it'd be a massive tyre size change.

It's one of those weird ones. I've no idea what caused it and I'm not going to even try explaining it. I might call Mr Mulder though!

 

[Peter ST_R]

well if someone can explain my revs dropping ill be glad to hear it coz im pretty sure i can read the dash right lol.
either way less revs less fuel im happy

You must have found fith gear!!!