Outer Limits 4x4 Board

OK, so im playing with the idea of trying to get more out of my 3L 2.8 engine.

Currently have a CT20 turbo which is only making 5 psi and nothing until at least 2500rpm.

which is useless or close to. where do your CT20's start to make boost?

What other turbos from toyotas or otherwise would fit without major refits?
CT26 or CT12A etc etc. or is the CT20 the only real option?

What I want to achieve is boost comming on as low as possible in the normal driving range. and say 9 or 10 psi.

Another option is to have the CT20 rebuilt (at say $800 - $1200) or ive seen in the search on this forum many people talking about 'hiflowing' the CT20 to get much better results.

any thoughts and experience would be awsome.

thehanko wrote:What I want to achieve is boost comming on as low as possible in the normal driving range. and say 9 or 10 psi.

You may need 2 turbos, like the BMW diesel racing cars.

It works in 2 stages, a tiny turbo for low rev boost, then the normal turbo for the top end boost.

sounds properly perfect... but way to much effort. I woult not even know where to start.

Good idea but im after an option which might not need as much customising.

when would you say is normal for the boost to come on on a CT20?

Just buy a turbo bleed valve and up the boost on ur current turbo, adding a bigger say 21/2" straight exhaust will lower the revs the turbo comes on boost also. Normally to get boost to come on sooner u wud add a smaller turbo which has less lag at low revs, personally i think for offroad use the CT20 is to big a turbo for the 3L in general as it does come on boost rather late but still works well.

thehanko wrote:when would you say is normal for the boost to come on on a CT20?

2000 RPM, around then + or - some revs and every setup is different

Firstly, what size is your exhaust and does your muffler have good exhaust flow ??

I'm guessing your exhaust is not flowing fast enough to allow the CT20 to spool up fast enough.

Like A1 Mech suggests, as least a 2.5" exhaust will help.
Mine kicks in at 2k as yours should.

If you know someone with a mig, cut the exhaust before the muffler and remove the back section, and take it for a run to find out, then weld it back on to keep dot happy.

So does that mean these guys are no good?



he he he. NO idea if they did the exhuast thats on the vehicle, but their on the back window of the car so lets blame them.

here are the pics of the exhaust from front to rear. it remains 2 1/2 inch all the way from the back of the turbo.







apart from looking a bit dirty I would have thought it was ok... but?

Looks like you don't have a muffler as such so flow should be OK , there goes my guess out the window

What sort of air box, air filter (I assume it's clean) and intake piping are you running ??
Is there a leak in the intake piping ??
Injectors are in good cond ??
Do you have the std cast bolt on bend on the back of the turbo which is quite restrictive ?

A bleed valve will allow higher boost but won't make it come on any sooner.

standard 3l air box - filter is clean.

I assume the outlet from the turbo is stock - looks old and is cast iron.

Not sure about injectors, but they were one of the things I was considering getting serviced at some stage. I seem to be getting good ecconomy of about 9L per 100Km which I would have thought was pretty good for an old diesel so it makes me thing the actual combustion is pretty good - injectors therefore are doing a pretty good job.

Doubt there is a leak in the piping, it was made by the previous owner, but he looks to have done an effective if not pretty job. would think there would be some loud air sounds if it was leaking?

hmmm, the trubo comming on at 2000 rpm would be so much better.

Think I'll have a play with the wastegate and make sure its not all just wasting out there. erm.. will see how that goes.

a1 mech wrote:Just buy a turbo bleed valve and up the boost on ur current turbo, adding a bigger say 21/2" straight exhaust will lower the revs the turbo comes on boost also. Normally to get boost to come on sooner u wud add a smaller turbo which has less lag at low revs, personally i think for offroad use the CT20 is to big a turbo for the 3L in general as it does come on boost rather late but still works well.

Agree with this guy. Up the boost to 10 or 11psi. Install a 2.5" or 2 3/4" exhaust.

CT20 is not too large for a 3L, just on the borderline of being too small. I had one on a 2LT, boost set at 11psi, rpm was always high.

thehanko wrote: Think I'll have a play with the wastegate and make sure its not all just wasting out there. erm.. will see how that goes.

Hadn't thouhgt bout the waste gate, your right, it could be sticking/stuck.

Ive packet out the plate by 3mm and will test it out on the way home and on a road trip im doing tomorrow.

seems to be moving ok, doesnt seem to stick or anything so i dont think its stuck open or anything like that.

will see and update after some testing.

cheers

good start!

OK so I packed out the wastegate by 3mm and have had very promising results.

Boost is beginning at 2000rpm now instead of 2500 +.

by 2500 its achieving 5psi without effort and max is now 7-8 under heavy load.

So a huge differance, instead of no boost at cruising speed I now have 5psi which really helped with the driveability. revs much better etc etc.

Still not a very high max boost so I will play around more with the waist gate to try to get it to about 10 psi.

should I get it re dyno tuned due to the extra air getting in now, or just wait till i get my pyro and then play with the fuel myself?

One thing to be aware of is a 2LT/2LT-E is built with lower compression to cope better with the turbo, e.g. 10psi on a 2LT/2LT-E will equate to about 7-8 psi (guess) on a 3L.
Unless of course the engine was set up to cope with the turbo in the first place.

I run 11psi on my 2LT-E and have been for the last few years.
Still origonal head, cooling system, Turbo, etc. and regular servicing.

Definately wait till you have a pyro and know what the EGT's are before upping any more IMO. My Pyro gets up to 500deg on long steep climbs and sensor is just after the turbo so exhaust manifold temps would be about 650deg at the same time ...... DAMM HOT !!

do you think i should drop the boost back to where it was until i get the pyro guage?

It was dyno tuned with a pyro 1000k ago but that was when it was making no boost.

My understanding is that extra air in a diesel (or less fuel which ever way you want to look at it) will reduce temps and reduce the performance gain from the extra boost.

but increasing the fuel increases the temp and power (to a certain point).

if my understanding is correct then increaseing boost wont hurt it?

more boost = more power = more heat

hmmm, should i pull out the washes before i do 500ks tomorrow?

If you have an aux temp gauge and can keep a close eye on what's really going on a bit then you may be OK, otherwise I would swap the 3mm ones for maybe 1.5 or 2mm washers if you have 500km to do and want to be more confident of getting there without overheating her.

In my books it's better to arrive a few hours later than a day or more later and a few hundred bucks lighter.

cooking it would be more than a few hundred.

Max egt's occur when under high load? is that right?

so for cruising i wouldnt expect high egts unless i was pushing it to hold 110 uphills etc.

Ill have a play on the drive with a few diffferent thicknesses and watch the engine temp, if its sitting any higher at all then i wont risk it and will rip them out. im not in a rush tomorrow.

thehanko wrote:Max egt's occur when under high load? is that right?

so for cruising i wouldnt expect high egts unless i was pushing it to hold 110 uphills etc.

Yea pretty much.

Have a good trip.

Dougster wrote:more boost = more power = more heat

I'd agree on a petrol, in fact with the diesel it will drop in EGTs provided the intake air temps haven't raised excessivly from the higher boost level. What does happen though is the power goes up but tends to flat line quite abruptly when all the fuel is consumed. The extra boost must raise the cylinder pressure (extra power) and maintain it for longer due to the extra oxgen allowing longer burn times and the fuel is more competely burnt by the time the exhaust valve opens so the EGT's are lower.
We recently replaced the stock turbo on a 3.0L with a roller and fitted an intercooler and a tuneable Rapid chip, we went from 60 rwkW to 108 rwkW with only a 10 degree increase in EGT's, adding more fuel increase power further but with an undesired rise in EGT's, due to the fuel not all being burnt in time and the combustion still occuring beyond the exhaust valve. This heats the cylinder head and piston excessivly.

Joel

Thanks ll the help guys.

Ive just ordered my pyro so when it arrives ill bump the thread and let you know how its all worked out.

but if anyone has good ideas in the mean time get em in.

mini holiday tomorrow

Interesting Joel .....

I notice that you have fitted an intercooler (top or front mount, air/air or air/water) which drops intake temps a lot and the turbo you have used may also be more efficient than a CT20.
My experience is (keeping every thing else the same) and upping boost pressure from 7 to 11psi increases power and raises the EGT's.
Have no black smoke (that I can see from inside the cab) before or after boost change.

The 3 litre engine you up graded, was it a 3L, 5L or 5LE or 1KZTE ??
What Turbo did you put in ??
How much did you raise the boost ??

What in your opinion is a good upgrade for a CT20 and or 2LTE/3LT??

I had the same turbo setup on my old lux running 14psi and it spooled about 1200rpm but alot of excess black smoke before that

Car drover really well and never moved on the temp guage. but the pyro will arrive soon and give me a better idea.