Turbo upgrade

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02 Oct 2016 22:21 #252 by Frank
Frank replied the topic: Turbo upgrade

Tony Lee wrote:

Result? No change that I could discern (apart from more noise!) Boost was the same at 12.5 psi, and the terminal speed in the steeper 4th gear section was just the same (a good indicator of power).

I did the same as you a while back and posted it, I could not notice any difference either.



two out of two!

Getting rid of the filters and the cover eliminates the restriction of 3 90 degree bends, 4' of pipe, the shield inside and two filters and a cowl all of which are claimed to be starving the engine of air. So if eliminating all of that serious restrictions makes no difference, how then can changing the entire filter housing to take a bigger filter and making fairly minor changes to the pipework between the filter housing and the turbo inlet make enough difference to be worth the trouble.


unless the cast section after the air filter and before the turbo is responsible for the majority of the restriction. I must pull my new filter and cover off and redo my testing and then test again with just the bare turbo intake. Mind you a pipe with a correct inlet shape (bell) is significantly less restrictive that a pipe that just ends, I think its all to do with laminar flow (any CFD physicists among us). So the bare turbo could be worse that a turbo with a pipe attached, so that may tell me nothing.

Frank & Christine Thomas

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03 Oct 2016 00:38 #253 by Tony Lee
Tony Lee replied the topic: Turbo upgrade
It is all to do with trying to determine which parts of the upgrade are going to give the most improvement for the least amount of money. Making 27 individual changes that result in a marked improvemeent and then saying that each change gives 1/27 of the improvement isn't valid. Yes, adding an intercooler IS going to make a huge improvement and those like Peter can attest to that. Changing the turbo is another major contributor and maybe even having a straight through exhaust does too - although I suspect I'm only one of many that already has a straight through exhaust.
Air filter upgrade? Guess if the old filters are at the end of their useful life then there may be a significant improvement that is more due to a new filter than anything else.
That leaves the snorkel system and the pipework between the filter and the turbo. If completely removing the effect of the snorkel AND filter is reliably reported to make next to no measurable difference, then maybe the pipework between the filter housing and the turbo is similarly insignificant

Tony

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03 Oct 2016 08:15 - 03 Oct 2016 08:27 #254 by Rick Whitworth
Rick Whitworth replied the topic: Turbo upgrade

Tony Lee wrote: It is all to do with trying to determine which parts of the upgrade are going to give the most improvement for the least amount of money......

And dyno tests dont come cheap especially if you are using a busy reputable diesel mechanic.
Eg I am looking forward to my after tune dyno results but the before results dont mean much. They found that all my injector settings and egts were very conservative. The af ratios, boost compensation max fuel setting and therefore measured output was way down.
He asked if I wanted it properly dyno tuned, but given the cost and partly on his recommendation that I will be having it done post upgrade anyway I could not see the point.
It is because we are all after ...the most improvement for the least amount of money... that it is hard to get comparative results on one OKA let alone confirm them across the group.
As Mort says ..in the end it is whatever one wants to do.. and thanks for his effort and everyones input. This forum is great.

The more ideas and info the better.
Rick
Last Edit: 03 Oct 2016 08:27 by Rick Whitworth.
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03 Oct 2016 08:32 #255 by John and Bronwyn
John and Bronwyn replied the topic: Turbo upgrade
Lots of useful comments.

Martyn, I think you are most likely correct to finger the cast section, all I have really done is show that the intake and air filter assembly is not the dominant restriction with the present state of the mods to my vehicle. (The last bit is important.)

I did some fluid dynamics study about 40 years ago and have done some pipework design for various fluids. I think the best description of the air intake pipework is "contorted" and there would be many losses due to bends. Bends close to the intake side of any blower are especially bad. Flow guides could help but would probably be an unacceptable risk of coming adrift and getting into the turbo.

I have no doubt it's a case of "diminishing returns" but the trick is to know what to change next (assuming you don't wish to do all mods at once). With the next restriction removed, the filter & intake may well be next on the list. I'm not sure I want to do the filter mod, the intake is already modified for other reasons.

I am very pleased with the gains so far, the vehicle is already much more pleasant to drive. It's all a matter of how much improvement you wish for and how much you are prepared to do!

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07 Oct 2016 15:56 #256 by Peter Davis
Peter Davis replied the topic: Turbo upgrade
Does anyone know what sort of Cast Iron is the turbo dump pipe made from (grey, SG, Austenitic, white, malleable)? I want to arc weld a bung for an EGT probe.
For those who have completed their turbo installations did you use anti seize on the nuts holding the turbo to the exhaust manifold and the bolts for the bracket to the dump pipe.

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07 Oct 2016 17:40 #257 by Peter and Sandra OKA 374
Peter and Sandra OKA 374 replied the topic: Turbo upgrade
Peter it is far easier to just drill and tap the Perky dump pipe, about a 100mm from the turbo it is about 6mm thick and as most of the probs are 1/8 or 1/4 NPT thread there is plenty of meat for the thread.

OKA 374 LT Van, converted to camper/motorhome,
400ah Lithiums, 1100w solar, diesel cooking heating and HWS,
Cummins 6BT, Allison 6 speed auto, Nissan transfer.

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07 Oct 2016 18:10 #258 by OKAPETE
OKAPETE replied the topic: Turbo upgrade
Like this Peter.....




Pete.

Chaplain. Won x One Chaplaincy.
AM SAE-A. AAFRB.

Oka 383. In process.... Cummins 6bt. Allison 2500 6spd. LOMAX 3:1 205 T/case. Dana 80 F & R.
Oka 358. Van. Perkins. swift turbo intercooled. NP205 conversion. LSD F&R. Camper conversion in progress.
LIFE.....is keeping OKApied.
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08 Oct 2016 05:14 #259 by John and Bronwyn
John and Bronwyn replied the topic: Turbo upgrade
Or drill & tap the inlet to the turbo before installation. Again just cast iron, and easy to do. Tap to set the fitting flush with the inside wall when tight.

The NPT (taper) tap will probably set you back a bit.

Measuring at the turbo inlet is a better indication of possible damage than at the dump pipe, if you can.

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11 Oct 2016 13:22 #260 by John and Bronwyn
John and Bronwyn replied the topic: Turbo upgrade
An update on the effect of the standard air filter / air intake.
A little while ago I did some tests whch showed no noticeable change in boost or power with the air filter cover off and both filters removed.
However...
I have done a couple more series of tests (different days, different weather, same hill) which show there is a difference - but not in boost or power. Each time I tested, I had a consistent reduction of about 20 deg C in turbo inlet EGT, from 650 down to 630C at 2200 RPM with the filters out & no cover.
This creates some room to tweak the fuel for more power while staying within safe EGT.
Re EGT, the EGT before and after the turbo behave quite differently.
The dyno tests showed after after turbo EGT rose smoothly across the rev range, from around 430C below 2000 RPM up to about 510 - 520C near 3000 RPM.
However pre-turbo temperature is about 670C at 2000 RPM, dropping somewhat to about 640-odd at 2800 RPM. The dyno test showed the excess air ratio was increasing with RPM. Hence engine EGT would be likely to drop, which is what happens.
What this means is that the rule of thumb suggested on some web pages (add anywhere from 100 to 150 deg C to after turbo EGT) cannot be relied on to keep the pre-turbo EGT to a safe value across the whole rev tange.
It is easy to drill & tap the new turbo for a turbo inlet pyrometer before installation.

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17 Oct 2016 15:26 #261 by 210greg
210greg replied the topic: Turbo upgrade
Half way thru doing upgrade to 366 all going well thanks Mort. Am thinking of just doing a straight thru exhaust ie No muffler has anyone else tried this or have any thoughts. Just kicken the ball?

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17 Oct 2016 16:36 #262 by Peter Davis
Peter Davis replied the topic: Turbo upgrade
Hi Greg
Many years ago Jurgen from Mornington, Victoria didn't have a muffler. It was fairly quiet at idle but could be heard from a fair distance when pushed along through the gears. I haven't heard or seen him for a long time to whether it is still the same.
I have contemplated doing it myself as I have a long exhaust system with vertical stack but haven't got around to it. Maybe with the turbo upgrade.
The gear linkage in the LT still comes very close to the new turbo in 4th gear. I bought 2, 8mm spacers and longer studs to join the end of the dump pipe to the exhaust flange to fill in the new gap.
I'm glad for the new turbo as I have found the wrong size woodroff wedge in the gear linkage and the grub screw loose which is probably the source of my gear stick rattle. The fuel pump lever in the fuel pump was floating about. The location bolt on the rocker rod had fallen off and a crack in the bell housing. Also I have degreased a tonne of sludge from the side of the block, wrapped the exhaust manifold and turbo oil inlet pipe, tapped the dump pipe in 2 places for the pyrometer and LPG cutoff. The return oil pipe hose virtually fell to pieces, so replaced that. It is 19mm ID about 3 inches long. I also fitted the lift pump handle which has been sitting in the shed for about 10 years. I remade the alternator mount to a lighter version. Mine doesn't appear to be original Perkins/Oka, made out of 10mm steel.
Still to finish exhaust connection, connect turbo to intercooler and put alternator back in before removing gearbox and clutch to weld up the Bell Housing.
Peter

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17 Oct 2016 17:34 #263 by Tony Lee
Tony Lee replied the topic: Turbo upgrade
I would be inclined to keep the muffler there for show even though it might be straight through just in case you do get pulled over for noise or run through a roadside weigh station. No muffler at all would be instant confirmation and likely a ticket, but muffler would get you out of it.
RTA have an app available so you can easily report rubbish dumpers, smoky cars and noisy exhausts. Unfortunately it doesn't have an option of reporting barking dogs, but I live in hope.

Tony

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17 Oct 2016 18:00 #264 by Peter Davis
Peter Davis replied the topic: Turbo upgrade
Tony have you had the pleasure of going through a weigh station? Did you have any daramas?
It puts one off travelling through NSW esp east coast.

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17 Oct 2016 19:40 #265 by mort
mort replied the topic: Turbo upgrade
Hi Greg I know of several OKA's with no muffler but I did put a free flow muffler which is purely for looks as I have had the once over several times all in different vehicles by either bored or curious country coppers I even got stopped for speeding in the OKA which cost many $ that was in NT after I had acquired it and driving home and that vehicle could not do the speed he said but I was not going to argue as it was hit district so the point is I dont want to invite trouble by someone saying it is illegal because it doesnt have a muffler forget the fact that it isn't loud and certainly quieter than the average Harley.
Martyn
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17 Oct 2016 19:50 #266 by mort
mort replied the topic: Turbo upgrade
Hi Peter I have been through weigh stations a few times. the first was when bringing my truck back from Sydney, second was with the OKA each time I was more curious than anything and bored with the driving but told I didnt have to stop as I was not a commercial carrier but I said the sign says all trucks have to stop the reply was only commercial trucks.
Martyn

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18 Oct 2016 06:30 #267 by Nobby
Nobby replied the topic: Turbo upgrade
Hi Allabout,
I have been following this story with interest.. I am not long back from a 4000 k trip to the Eastern Kimberley.. in 187, and apart from issues with the AVM free wheeling hubs losing the screws on corrugated roads.. I returned with only 3 screws per side, they loosened faster than I could tighten them.. I don't need more screws as a pair of new Warn Premiums are on order..
2 days before departure, I saw fuel pouring [not dripping] out from under the Bosch injector pump head.. Time looking at the Forum on VE pumps was a plus.. and gave me the courage to attack it.. I also had the advantage of having a complete VE pump in a thousand pieces, so was able to look at it all before I attacked. I have repaired many CAV pumps, but never a VE.
I did have difficulty fitting the two springs back into the head.. and got around it by grinding a lead / taper on the ends of what goes into the head to facilitate entry. I also fabricated the special tool to access the lower pump attachment nut.
The sigh of relief when if fired up was beyond belief!!!
On the last leg, returning from Darwin empty [Had left my guests at Darwin Airport] I recorded 120 kph [GPS] crossing the Fergusson river, so I must have got it right.
I have checked 430 throttle functions, and there was room for improvement, which I have sorted.. but it made little if any difference. Now the pressure is off, the busy season over, I will look further.. I will check the diaphragm in the top of the VE pump.. and if that is OK may look at some adjustments there.
I note with interest some of the boost pressures mentioned.. and know that 187 with intercooler at full noise only has 9 to 10 psi max boost pressure.. so it seems that the intercooler is detrimental to boost pressures... I also need to find and fit a boost pressure gauge to 430.. which I am told had been fitted with a new turbocharger.
Thanks.. enjoy your day
Nobby.

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18 Oct 2016 07:02 #268 by Tony Lee
Tony Lee replied the topic: Turbo upgrade
Yes Peter. One of my vehicles is a 17 tonne tag axle coach and that gets hauled in but normally diverted back to the highway.

The OKA would have to call in at the station just north of Alice Springs wouldn't it.

Tony

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18 Oct 2016 20:06 #269 by mort
mort replied the topic: Turbo upgrade
Hi Nobby
Depending on your intercooler setup having a boost pressure of 10 is ok. I started with max 14 until I fitted the intercooler then a reading of max 10. The intercooler is mounted up under the bash plate with 2.5 inch piping to and from so to get a reading at the air box the turbo has to pressurize from the turbo down to the intercooler through it and back again, the problem is the std turbo is not capable and the specs are that max Hp is achieved in this case 110 at 2600 rpm which is not in an Oka's normal driving range.
All is not lost as what you loose in boost pressure you gain in dense cool air so it evens out and is better anyway.
The drop in boost is one reason why I set about designing a turbo that would start boosting early and reach full boost at around 2000 rpm and even though I am happy with a boost of 16 max I know of one Oka that is now achieving a max of 20 and boy is he happy,I had received some photos but with phone stolen so went photos and his number but when he rings I will get some more as he doesnt get on the site much.
Martyn
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01 Nov 2016 07:38 #270 by OKAPETE
OKAPETE replied the topic: Turbo upgrade
Prior to my recent trip across the paddock I fitted the waste gated turbo to Oka 224 (Grizzly) that Martyn went to so much effort to get right.
I previously had fitted an air to air inter-cooler to the Perky going back 10 years now when traveling with the family and towing our 30' fifth wheeler and at the time I had it dyno-ed before and after and it went from 76hp to 92hp at the rear wheels, considering it is allegedly 110hp at the flywheel, there is a lot of loss, mainly due to the Rockwell.
I didnt/havent had time to dyno this time since fitting the waste gate turbo but with a GCM of approx 8 tonne I am more than happy with the result and would recommend it (combined with an intercooler) to anyone who wants a power upgrade, if not wanting to go the transplant option.
I didnt touch the pump this time, and it will require a small increase of fuel I feel, but it holds boost better between gear changes and on average sitting on 13-14 lbs boost and up to 17 at peak, given that this is charging the intercooler and piping I am more than happy....for a Perkins 4 cyl. However.....should I continue to tow these kind of weights and push into head winds like I did on the way across...it would be much easier on the right foot and pressure on the sciatic nerve if I wasnt holding the pedal down as much.....so....the 6bt sitting in the shed is looking like it may happen sooner than later.
Blessings. Pete.

Chaplain. Won x One Chaplaincy.
AM SAE-A. AAFRB.

Oka 383. In process.... Cummins 6bt. Allison 2500 6spd. LOMAX 3:1 205 T/case. Dana 80 F & R.
Oka 358. Van. Perkins. swift turbo intercooled. NP205 conversion. LSD F&R. Camper conversion in progress.
LIFE.....is keeping OKApied.
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01 Nov 2016 11:32 #271 by 210greg
210greg replied the topic: Turbo upgrade
Turbo now fitted to 366 exhaust done air cleaner done not no dyno as yet Gear linkage may have to be modified as is hitting in forth gear I thought this was only an issue on the xt's
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