Andy's Custom Turbo Install.

[InVinceble]

Since I am running a VF-10 (almost), my set-up looks reasonably similar to the pictures above.
However, as I'm only running a 2.5" exhaust (and more importantly we are talking diesel power here) the need for a seperate dump pipe is overkill.
The bypass valve in practice does not ever fully open, the actuator doesn't have anywhere near enough movement. Therefore the valve itself impedes the flow of gas to the dump pipe, begging the question is it really worth it?
The open valve actually "directs" the diverted gas back into the "main stream". So I had a single hole plate put on my exhaust.

All that said, I'm still not happy with the performance I'm getting... working on the air in side at present.
Who had the info on K&N filters?

[dasnoboarder]

As the 3.1L engines seem to work best with the 15-R housing, and we have discovered the gasses produced by Jarrad's 3.1 and my 2.8 are quite different, we have decided to go for a 12-R housing on my turbo (if he can find one).

This should be a good comprimise between early boost, less restriction than the standard 10.5-R, improved top end, and should spin the turbine fast enough for the high boost numbers.

The 12-R housing is found on the VI83 turbo (for another Isuzu application), and according to Jarrad, because they're all RHB52 and Isuzu turbos, it should swap straight on to my turbo.

When the time for testing comes, keep in mind everything else on my engine is stock, apart from a K&N (part number E-2345). So boost will come on later than it would if I had the dump pipe and exhaust done...

I'm glad that butterfly valve is completly gone, looks tidier and anything that frees up space in the engine bay is a good thing...

[dasnoboarder]

Hey.

Had been thinking about the turbo again recently... Was so confused why it would start to spool and then hold at 6psi...

Thought it had to be the wastegate opening... Couldn't think of anything else.

Ages ago, we tried testing it without any boost controller, and then with one from my mate, same results, hold at 6psi.

So, tonight I borrowed a different controller from the same mate, and opened it all the way up, max boost.

The results, went for a drive,
2000rpm 0psi
2500rpm 6psi
2900rpm+ 10psi (pulls hard, most boost i could get)

This is a improvement, but still not drivable really...

Even with the exhaust done, extra fuel, etc etc, I don't think the revs that turbo really kicks in will drop low enough... And I will want to run more than 10psi.

What do you think?

[geeves]

Were the earlier tests done with no load. With my car free reving to 4000 only gets about 5 pound of boost although is got 12 pound at 2000 14 by 2200 to 4000 droping to 12 by 4200 with foot on the boards and a decent load on the engine.
Where are you taking the pressure reading from?
Have you tryed with the pressure feed to the wastegate disconected. Also try removeing the pressure relief on the top of the inlet manifold and sealing the hole (dont run peranantly like this) and see what happens.
What mods have you done to the inlet side of things. 14psi requires twice as much airflow as no boost

[dasnoboarder]

No boost controller and first controller were tested on road properly.

Then disconnected wastegate feed, blocked, and free reved, got the same old 6psi.

I'm taking the boost from a "t" in the line that connects from the "2800 turbo" stamped inlet piece to the fuel pump (I believe).

I thought the overboost valve only kicked in at 15psi...

I've got a K&N filter... and that's it for the inlet, everything else standard.

[geeves]

Overboost thing should only work over 15psi but might be faulty

[dasnoboarder]

Just an update.

After quite a delay due to courier company thinking my house doesn't exist, finally got the new housing.


(standard 2.8L 10.5-R on left, new 12-R on right)

Should be going on soon, no doubts this smaller housing will make boost much better)

Andy.

[beau]

wizbru said:

I'm not claiming any knowledge of turbos but

I would have thought that if you double the size of the exhaust turbine etc then you would need a lot more gases to spin it. An engine can only produce a limited amount based on cc rating and a few other factors. We get greater boost pressures because the engine restricts the amount of gas(air) we can push in at any given moment. I would suggest that bigger is not away better - particularly on the exhaust side of things. That's my two cents worth anyway

this is where the term "hybrid " is mentioned.... it is when a small exhaust housing and small exhaust turbine a custom fitted to that of (say for example a t56 garrett) this lets a small capacity engine run a big turbo and big boost at low rpm

this is why when you upgrade an aftermarket exhaust, and larger external wastegate are need to control the 24 35 psi you would be running on a t56...(hypothetical ofcourse)

but dont be confused between an external wastegate and an externally dumped wastegate.

internal wastegates are what you see fitted to the isuzu's factory turbo.

external wastegate is seperate from the turbo charger and is plumbed back into the exhaust system bypassing the turbocharger completely. (plumbback)

externally dumped wastegate's are illegal on road going vehicals however that doesnt mean you cant have this set up on your offroader as this is the best way to dump pressure in any situation.

so the next time the guy at the turbo shop tells you that you need a TD04/06 H turbo charger you can reply( ill need a 40ml external wastegate with that wont I?)

[dasnoboarder]

Just got it back from Alltech where they fitted the new 12-R housing today.

Finally stays alive between gear shifts, the boost is available at lower revs.

I'd say only marginally quicker than in the first place with the standard turbo , but i guess the real test will come when the exhaust and intercooler are done, and I have another modified MU to compare with...

;D

[quack]

what boost you doing and what rpms??

ive got a tap set to 14psi, it does about 10psi at 1750 and 14psi at 2g and then dies back down to 12psi just after 3g, it starts spoolin at 1500. when its under load it spools up even lower.

my mus got standard air filler, intercooler and the fuel turned up.

you will notice a big diff when you turn boost and fuel up if your running low psi now

[dasnoboarder]

Hey quack

I'm still on the standard boost of 10psi for now (no intercooler, standard exhaust).

I'll double check, but I think it gets up to full boost around 2000rpm, with K&N filter.

Will definatly do fuel and boost after a few more upgrades and exhaust temperature gauge.

Cheers, Andy.

[bagrodeo]

It comes to my head from an article i read somewhere that if you enlarge the intake compressor and leave the exhaust impeller the same size the turbo will spoll up as normal but give you more air into the intake that coupled with a bit more fuel then you should get more hp. As for the smoky bit did you replace the air cleaner with a new or even better a free flowing one ? beacause if not and the filter partly blocked you may be draging block fumes into the intake hence the smoke. If the exhaust impeller is to big it will take more air to turn the smaller the faster it will spin for a given air flow, this comes to me from some where but to the truth of this info i have not yet trialed so good luck if you us this as a thought process.

[dasnoboarder]

Hey

I have increased the intake compressor to the VF-10 size, and increased the exhaust wheel only a tad with the final set-up. My thoughts behind this are that the standard turbo on the 2.8L engine is a bit restrictive. With a free flowing exhaust, that helps spool the turbo quicker, a small increase of the exhaust housing/impeller will allow better flow through the turbo, while maintaining pretty standard boost characteristics (in the way of lag).

I've got a K&N air filter, but that should be needing a clean by now.

Andy.