My twin turbo experiment = 46psi

[Dzltec]

Here is an experiment I did with compound turbo charging on my 80 series 1hdt engine. I had already pushed it to the limit with the standard turbo, running around 18-20 psi boost, getting roughly 110 rwkw (this is a constant 4wd vehicle). So I decided to see if the maths would work when you add a bigger turbo feeding the original.



Well it works very well, so well I cant get enough fuel in the top end to use all the air. It isnt intercooled at the moment as this is another experiment im trying. With the vehicle hitting 125rwkw, the exhaust temps will hit 550c in a reasonable time, but no qicker then with only one turbo. The vehicle is completely standard apart from a 3" Beaudesert exhaust system. If temps do get too hot I turn on the chemical intercooling to cool it a little with a little more power thrown in.

The original still pumps out 18 psi, the larger one goes to 20 -30 psi, combined figure of 46psi.

Driveabilty is fantastic, no lag, just an enormous amount of pulling power.
Fuel economy check from Lilydale to Dromana and return towing a 6x4 trailer returned 21mpg. Most of it was driving like a nana, but there were a few squirts to see what it would do once you were cruising at 100kph.

Photos and dyno sheet are to come as soon as I find my cable for my camera.

Will also be going down the 1/4 mile soon to see what it does.

Feel free to throw up any comments.

[crankycruiser]

sounds Mad

Love to see some pics

[OISTA]

[vSAHARAx]

How will the big ends and stuff handle it?

Can ya smoke the tyres yet?

Good Work

TOYOTA TOUGH!!!!

[beanz2]

Dzltec, how long have you done 18-20 psi boost on the engine? Are you running the factory turbo to get the boost that high?

If your injectors can't give you enough fuel in the top end, don't you think you'll run cooler exhaust temps instead? What about adding an inline fuel pump near the fuel tank?

Dave

[dumbdunce]

there is something BAD going on there is you can only make 125rwkW @46psi boost. at the flywheel, a 1HD-T at that sort of boost should be makiing somewhere in the region of 200 - 300kW, or very roughly 140 - 240kW at the wheels, even in a constant 4WD.

If the EGT's are hitting 550 and it's running lean, there is a serious restriction or one or both of the turbos are operating way outside their efficient range, and intercooling isn't going to fix it.

interested to hear/see how you have routed the inlet and exhaust plumbing - to get sequential turbos to work properly takes a fair bit of roogering around.

twin, small turbos in parallel would be better value on such a motor - a big, secondary turbo is really only needed on an engine that has a very wide rev range.

[MACK1]

Dzltec, I would be very interseted as to what you have done to the engine as im rebuilding my 1HDT at the moment,When i get the time. Where balancing and blue printing the bottom end, And shot peening the rods,machining the cranck,running new armour grooved pistons and slightly machining the head. i was running 15psi everyday around town but am looking to step it up to 18psi.the basic bottom end in the 1HDT's are pretty good(oilsquirters/ big solid main girdle etc) Any hints/comments as to what to keep an eye on would be great. Best of luck with the turbo setup. Keep on posting.

[Dzltec]

To answer a few questions, big ends were checked and everything looks fine, time will tell.



The vehicle has been running with 18 psi for the last year. Yes the standard turbo will do it, but I dare say its gettiing out of its efficiency range. Injectors have been modified to try and see if they will let more fuel in. This vehicle already has a low pressure electric pump fitted.

Dumbdunce you are probably right in that there may be a restriction. It could be a number of things, something which im looking into. My thought on high egt's is because of the inlet air temp, something I havent measured yet. It also could be the original turbo not allowing enough exhaust flow through it, or the exhuast system itself. If any turbo is out of its range it will be the ct26. Small twins may be ok as well, but the way I saw it they would not make this sort of boost pressure, there would be more work to make them fit, with not a lot of real difference than a standard turbo.

Making them fit and match did take some time, the outcome looks very neat, except for the crossover tube. The factory a/c is still fitted and working.

I am hoping to get more out of this, but seeing no one in australia could help me, I have had to rely on info from the states where they do this to quite a few vehicles. Guess Im the guniea pig. The engines that they they compound turbo have a max rev limit of 3600 rpm, not very broad.

But they do have a diesel dragster 5.9l twin turbo, 6 cylinder that runs 7.98 second quarter miles.

Thanks for the comments.

[awill4x4]

46 psi and non intercooled I'm betting your compressed inlet air temps are so high you couldn't fly over em with a jumbo jet.
Regards Andrew.

[Dzltec]

Mack 1

you could oring the block or head and fit head studs for more clamping effect and security in the cylinder head area, port clean up and throating of valve seat area also works well , if done by someone who knows what they do.

My engine is completely standard. Another will be built with head studs oringing, head work and camshaft to replace this one.

Hope this helps

[dumbdunce]

from that dyno sheet it appers that either or both (a) the big turbo is too big for the motor (b) the motor runs out of fuel at 125kW.

big boost without intercooling is not necessarily a problem in itself, and the fact that the EGT's are low suggest that the turbos are not adding a lot of heat to the inlet air so I wouldn't be too worried on that score - in fact it is probably the sheer size of the big turbo, hardly working, that means (a) low EGT's (b) boost building all the way to redline instead of building rapidly and plateauing.

do you have any specifications on the big turbo? A/R ratios and port diamters for starters?

[Dzltec]

Dumbdunce

Do I detect I slight change in tone . Yes you are right, as I said I cant get enough fuel in at the top end. I didnt intercool it for the reason I wanted to prove that this would work. Work, it has indeed. The bigger turbo may be on on the slightly larger side but I think I can raise the rev limit to 5000rpm, on the next engine I build and this will suffice. Turbo specs are secret to a degree, inlet .7, ball bearing garret, 4" inlet.

By the time max revs arrive the bigger turbo is doing around 26 psi. I think this system will need and external wastegate between the two turbos to make it work better.

Future ioptions are also lpg fumigation, nitrous, water/methanol injection. I looked under it today, I can see alot of room for a 4" dump exiting at the c pillar. jUst need time to make it.

Call me if you wish. 03 9739 5031.

Cheers

Andy

[Bundy_Harry]

Dumbdunce

Do I detect I slight change in tone

Are you bragging?

Maybe you should have just PM'd him in private rather than keeping all your secrets to yourself and scoring points in the public forum

NO points scrored with me, in the public arena
Dumbdunce 1
your ego 0

Flame me if you want, I dont give a st*ff, I have 7 James Squire strong ale's under my belt

Cheers *with number 8*
Bundy_Harry

[madmont]

Over 20 years ago the tractor pullers were using 100 psi turbocharge with ice intercooling and getting 2 hp per cubic inch with their diesels at half the revs of a petrol motor. Today they talk about up to 200 psi and up to 4 turbos to provide the boost

[Shadow]

Dumbdunce

Do I detect I slight change in tone

Are you bragging?

Maybe you should have just PM'd him in private rather than keeping all your secrets to yourself and scoring points in the public forum

NO points scrored with me, in the public arena
Dumbdunce 1
your ego 0

Flame me if you want, I dont give a st*ff, I have 7 James Squire strong ale's under my belt

Cheers *with number 8*
Bundy_Harry

wtffff????

[Ruffy]

I'm with Dumbdunce on this one.
There seems to be some confusion on the EGT's. 550 is not high for 46 psi.
Also 46 psi should be producing more than 125 rwkw i would have thought. Remember turbos don't just create pressure they shift air. If the first one in line (smaller) is spinning a shit load faster than the second (big) one then neither of them will be anywhere near there peak performance and hence be as useful and little blue lights on your washer jets, they'll be for appearances only.
Your idea is great but just bolting shit on isn't going to get you best results.
Lastly, if you're gunna bang 50 odd pound of boost into a 6cyl diesel then you're gunna need to burn a bucket fuel so don't bother giving us some nanny driving fuel consumption figures. You want power, you ain't gunna have good F/E
Good luck.

[hokey]

I thought alot of the winch challenge patrol diesels were getting about 150kw at the wheels????

[eliteforce32]

yeah thats with modified fuel pumps, single turbos, with methnol or lpg injection, more to the figure of around 200RKW's

[hokey]

i guess if he has air which he has plenty of he just needs the fuel system to keep up and he will make power like that

[Dzltec]

Bundy Harry, no bragging here. Just that his response had altered.
If I have flamed, it wasny done intentionally.

Yes I should have more power, all i have to do is modify my pump to do it. At the moment time is against me. The purpose of this post was to show what can be done to a diesel, that boost isnt the killer to most blow ups, and also to see how far I can go with it. Its my experiment that I making public.

Ruffy, the reason for the fuel economy bit was to show that you can have power with economy if you drive accordingly. If I was to drive this flat out all the time, yes it would be shitfull.

Also realise that boost doesnt make power, adding fuel does. I now have all the air I want, all I have to do it up the fuel.


Cheers

[Shadow]

I'm with Dumbdunce on this one.
There seems to be some confusion on the EGT's. 550 is not high for 46 psi.
Also 46 psi should be producing more than 125 rwkw i would have thought. Remember turbos don't just create pressure they shift air. If the first one in line (smaller) is spinning a shit load faster than the second (big) one then neither of them will be anywhere near there peak performance and hence be as useful and little blue lights on your washer jets, they'll be for appearances only.
Your idea is great but just bolting shit on isn't going to get you best results.
Lastly, if you're gunna bang 50 odd pound of boost into a 6cyl diesel then you're gunna need to burn a bucket fuel so don't bother giving us some nanny driving fuel consumption figures. You want power, you ain't gunna have good F/E
Good luck.

He said he was experimenting (hence the less than perfect setup)

He said he cant get enough fuel into it (hence the lack of power)

As for EGT being too high, that would largely depend on where he is taking his reading (pre or post turbo(s). if post turbo's the EGT could already be on the limit of what is considered BAD.

I dont see how you can be taking dumdunce's side on anything, its not like dumbdunce has really offered a differing opinion, rather, he has just pointed out things that dzltec should think about.

[DanielS]

Hey Dzltec,

Have you tryed just running the larger turbo by itself?

[Dzltec]

DanielS,

yes I have, it happened by accident when the wastegate lever fell off the small one, i wondered why it was so laggy.

The larger one is a real big turbo, the two combined help each other. The smaller one being driven first is able to draw air out of the bigger unit, this then helps it spool up.

Are you the danial from perth???

Cheers

[DanielS]

Yeah it is, is that you Andrew?

[GRIMACE]

Yeah it is, is that you Andrew?

luv is in the air.... everywhere i look around

[Ley269]

The original still pumps out 18 psi, the larger one goes to 20 -30 psi, combined figure of 46psi.

I might be wrong here and feel free to correct me, but it won't matter how much boost the original turbo is producing, the end result at the motor you say, (from the larger turbo) is 20-30psi, so you aren't putting in 46psi at the motor at all. The small turbo is only 'driving' the impellor of the larger turbo. It is not adding any more boost to the motor than what the larger turbo can produce, it is just helping it reach that boost quicker.

[Dzltec]

Ley,

the boost figure is correct it was taken 3" from the manifold, after both turbo chargers.

This is the whole idea of running ttwo turbos, it increases the amount of airflow a lot more, and has very little lag with it.

[awill4x4]

No, I think Ley is right. If you've measured your boost pressure in the manifold after the turbo's then that figure is the final one it's not a case of adding the 2 together. So if your real boost pressure is only 20-30 psi and if it's at the lower end of the scale that would explain your apparent lack of significant power gain (110 kWatts Vs 125 kWatts.) if as you say your original single turbo was pumping 18-20 psi already.
I think the power gain is more likely to be the larger turbo being within its compressor efficiency map (so less heating of the intake charge) while the smaller one is out of its map when its pumping 18-20 psi.
Regards Andrew.

[Ley269]

This is the whole idea of running ttwo turbos, it increases the amount of airflow a lot more, and has very little lag with it.

Yes, thats right, more airflow, NOT boost. Unless the boosted air from the first smaller turbo is going into the motor (which it isn't, it's just driving the bigger turbo) there is no way it can increase the boost produced by the second turbo. All turbo's have a maximum boost due to the compressors design and efficiency even without a wastegate. I'd say you have reached that maximum running the larger turbo at 20odd psi. Your power gain is from the extra VOLUME of air being forced into your combustion chamber.

[Dzltec]

Seems I have wronged by posting a new post with my pics I apologise for this, so here they are plus a diagram of how the system wotks.


Yes the ct26 may be out of its limits, this is an experiment to see what works and what doesnt.

There is no adding of pressures, two different gauges have been fitted at the manifold, both read the same figure. My lack of power is I cant get more fuel in under higher boost pressures and not down low. Its will take some time to sort this out. It does prove that I can make a lot of boost with te same amount of fuel though.

I hope this makes it easier to understand. Thanks for the feedback.