Hybrid turbo..

[Jonny81191]

http://www.ebay.co.uk/itm/UNIVERSAL-T3- ... _500wt_969


Would this be a good option for my HDi? I'm not too clued up on turbo's, so thought I'd check.

[Dan!]

In short - No.

[Jonny81191]

in short - why?

[Chris]

Way to big (presuming its a t3/4 hybrid, cba looking on my phone), and those cheep chinese ones are crap.
Iveco ko3 hybradised into the standard hot side imo is the way forward.

[Dan!]

In long - Its a cheap chines 'copy' turbo which would probably shit itself with 20psi. I wouldnt expect it to last long used at any kind of pressure though And also, even a geniune T3 or T4 would be a bit big for a mildly tuned HDi (stage 1 or 2), you'd want to rev the engine to probably 5.5k to get the most out of that and without specialist maps they struggle to push any proper power/fuelling past about 4k usually.

So in conclusion. Spend less than that on a second hand genuine turbo, with something like a GT17 or GT20 kinda frame

[Chris]

They are mappable to 5.3k without fiddling with map paramiters, but most tuners won't put the fueling in higher up the rev range for some reason.

[silverzx]

Probably because it may cause premature engine failure which then leads to the customer pointing they're finger at ..

[declantg]

but.... 500BHP....

[4WayDiablo]

but.... 500BHP....

what about it? not really acheivable on these engines without a lot of time and money

[pugbug]

Personally I wouldn't go for anything bigger than a GT15/17 Hybrid. I'm not sure how the majority of you drive, but adding a bigger turbo on a HDI completely ruins the car, having to rev quite high up in the rev range just for the power band to come in and then level off almost instantly is pretty pointless, at the end of the day you drive the car on the roads, not a race track, so no point setting it up like that. My stage 3 HDI hasn't been mapped up fully yet, but I can crawl up hills in my other GT15 HDI, in a high gear with lower revs, without labouring the engine, my stage 3 one will always need much higher revs or it will struggle as the torque band is much higher up in the rev range. - Just a perspective from an owner who's been there done that.

[Midnightclub]

If you want more power and more/the same driveability then get a VNT

[Ruan]

If you stick on a MODERN bigger turbo, they're absolutely fine...

I've said it before, I'll say it again, my GT2052V (yes it's VNT, but a GT2052S would be surprisingly similar) is LESS laggy than the XUDs T2, it's only slightly laggier than a GT15... The boost threshold is so low that it'll surge below 3000rpm it can pump that much air...

Anyone who says a bigger turbo car is undriveable hasn't driven one that's well tuned or is expecting to have that lump of torque, which makes it FEEL impressive, but you don't actually go anywhere other than raping clutches, it's maintaining that pull up to the high RPMs, which no HDis seem to do... Make them rev properly, and they'll be quick and better to drive.

T3/T4 hybrids - just no, 1970s technology, way too big, they're exclusively wanked over by Ford owners with RS Turbos/RS Cosworths, which are also basically from the 1970s because "Dat cosseh ad one dose t3/t4 'ayebrids n dat is fookin' well fast init"...

[darrenjlobb]

What Ruan said really.....

Just the typical example of people raping "big power diesels" because all they have ever been in is a poorly tuned hdi / stage one XUD, which makes them think they know what a diesel is like...which is just silly really!

[mark_airey]

What Ruan said really.....

Just the typical example of people raping "big power diesels" because all they have ever been in is a poorly tuned hdi / stage one XUD, which makes them think they know what a diesel is like...which is just silly really!

And again this ^^ Mine is fine to drive, its daily driven to work and back and is fine in traffic/town etc...............

[Dum-Dum]

As above, GT20 or K03S or similar.

[Ruan]

The K03S is a 50mm Compressor wheel, very similar to the Compressor used on the GT1749VA that's used on the PD130 and PD150 engines... The 1749VA is a 49.5mm compressor, they're good as "Stock" for about 130hp... So you can extrapolate yourself, HDi90 turbo will do 150 tops, a turbo off a 130-150 will probably do 180-190 - but IMHO, the turbine wheel on the K03S and GT17 frames etc is too small...

You're better off going for the bigger hotside (GT20+ or K04) and finding someone who knows what they're doing with mapping to make it respond properly... Half the problems with the HDis and their hydraulic lifters is due to exhaust backpressure, they use TEENY TINY turbines... Half the advantage of a Direct Injection is the fact you can produce SO much more oomph without boost, IDIs are crap with no boost, whereas DIs can produce loads of it with no boost... You may as well take advantage of this by giving it a nice big turbo, and allowing the fuel lower down...

HDis as standard are mapped SO lean in the bottom end.... You can add so much more fuel down there without smoke, HDis were designed to run smoke free in the desert when it's 40*C outside...

[Chris]

Ruan thats the problem though, no one will map them properly.
When Bryn (IIRC) had a bigger turbo on his mapper (not TB) was still cutting the fueling at 4k even though it would be good for power past 5k.

[Midnightclub]

IIRC it was prosteve who mapped bryns before TB took over

[Chris]

and Whippy, Steve will pretty much map what you want.

[Poodle]

^^^ This, he takes your order, advises of any concerns, then carries on regardless if you tell him to do it anyway. As long as you promise not to sue.

[Jonny b]

Lol at you Ruan not in a bad way as you know!!

Turbos, eat, turbos, shit, turbos, sleep, dream about turbosand wake up and repeat lol

[Ruan]

Mate, my snore as you know is very close to turbo chatter...

[Mattcheese31]

Mate, my snore as you know is very close to turbo chatter...

. . . . . . . . . . .

[Mr Whippy]

They are mappable to 5.3k without fiddling with map paramiters, but most tuners won't put the fueling in higher up the rev range for some reason.

The problem is that the power curve drops off rather rapidly over about 4500rpm, mainly due to the mechanics of the diesel combustion, but also the engine configuration which is generally the same in most diesel road cars (piston velocity wise)

So although you can inject more fuel and rev harder, you are increasing inertial loads massively by revving harder (Kinetic Energy ~ velocity.squared), and you are also fighting more engine friction (friction ~ velocity), and since the burn itself is becoming hugely inefficient for a given engine torque output, you do make power, but it's horribly inefficient.


Thus most curves I have ever seen on a high revving diesel actually don't get higher after about 3500-4000rpm, they just plateau. Thus if you achieve maximum power at 3500-4000rpm, and have anything near standard 306 Td/HDi gearing, you don't need to rev beyond 4000-4500rpm, since if you change gear you are back in the peak power again anyway.

So all revving does is achieve higher road speeds per gear at the cost of a lot more heat and inefficiency. Heat is bad because you need to get rid of it. The OEM heat dissipation requirements are for 90bhp/4000rpm, so throwing in four times more fuel to make maybe double the power at 5000rpm, is a big load!



The benefits are that you can run a high peak power output if you use less torque at more rpm, which means you can then avoid heavy duty clutches/gearboxes, general drive-train stuff.
Ie, you can run a 5000rpm engine to get 250bhp, or a 4000rpm one, but the 4000rpm one will need to run about 5/4 more torque to achieve that power at those rpm. That is only really going to be a concern for people racing diesels though, not road car users...


The last car I saw that ran 5000rpm, made it's 180bhp from 3000rpm > 5000rpm. But due to gearing, it made sense to just change at 4000rpm in each gear anyway, so running 180bhp all the time from 3000 > 4000rpm... using the 4000 > 5000rpm section just meant generating more heat, more engine wear, more risk of failure, more fuel consumption, to go no faster at all.


It is one thing having a turbo compressor wheel that will flow air for a stoich burn with a given amount of fuel that equates to X power at Y rpm... it's another thing having an engine around it that will cope!

You also need to deliver the fuel to the cylinders in good time, so you need a fast injection (pistons move bloody fast at 5000rpm), so you need lots of rail pressure, so you need lots of pump pressure. A fast pump generates heat, so the fuel is hot, and expands. You also need BIG injections to make power at increasingly high rpm, since the efficiency falls off a cliff.

The mechanics simply mean it's gets really hard to do what you think is easy.


200bhp/265lbft worth of fuel at 4000rpm might be say 200mg/injection, 1.325lbft/mg/inj

200bhp/210lbft worth of fuel at 5000rpm might be say 250mg/injection 0.84lbft/mg/inj


You need to pump in maybe 55% more fuel to make the same power, because you rev 25% higher.


But, piston speed is also 25% higher, so your window to inject in a timely manner is 20% smaller.

You do however have the benefit of 25% more pump speed, so you can expect about 25% more flow from it.

So you need to get 55% more fuel into the engine, in 80% of the time. So you could say you need 25% more rail pressure to generate the required time improvement, THEN you need to pump in 55% more fuel too, and that puts a load on the pump which is only spinning 25% faster than before. The fuel will also be hotter too.

If you have a superior fuel cooler, a bigger fuel pump running a faster pulley, uprated injectors and sufficient air flow, then you could perhaps run the fuelling you want to make big power at big rpm with the matched turbo compressor.

However, you are ignoring the cam shaft profile which is out of it's depth at 5000rpm and such massive exhaust temps and pressures at such rpm. Valve lifters. Oil temps spiking. Coolant temps.

Does your bottom end have sufficient strength/lubrication to run 200lbft at 5000rpm?


Lots of variables of course.

I see people specifying a turbo to run the flow required, but is everything else capable too?

Tuning a car like this properly is damn hard work, it's a partnership between the tuner and the owner, it takes a lot of time, patience, and basically earning very very little to do it when you count out the hours you have spent. And since each car is rather unique, very little can be taken to the next project.

Ie, peak rail pressures are a function of the pump, pulley and temps they run at, which dictate how you calibrate your advance map, and that can then impact the smoke map, and on and on it goes.



Don't see this is making excuses, it's not.

Simply wanting a high revving HDi because you think it's the easier way to higher power is incorrect. You have just as many hurdles, or more, making 200bhp at 5000rpm, as you do at 4000rpm.

Specifying a turbine and compressor for a turbo is the easiest bit of the job. Making the engine injection system actually deliver it (not just requesting it in mapping, but checking you get it) and the engine physically cope with it, are the hard bits.

Does anyone have a finished one yet? Any at wheels dyno plots off a Dyno Dynamics rolling road or similar?

I've seen Pete make big power, and other high power HDi's around, but none of them are making their peak power at 5000rpm+! More like 4500rpm tops, and plateauing earlier still... and at 4500rpm, another 500rpm is a LONG jump when in the world of diesels.


Sorry for the VERY long post

Dave

[Poodle]

[/thread] !!

Thanks for that Dave, although i knew all of this i'm not sure i'd ever put it all together in my mind quite like that before, makes you think...

[Mattcheese31]

awesome post......

[Mr Whippy]

Remapping these cars is a labour of love when swapping injectors, pumps, turbos, trying to add vnt, whatever else. I guess most tuners are getting about £1/hr average in the end, if not less. And 90% of that time is spent just diagnosing hardware issues or interpreting feedback issues, not learning new things per se... that is usually done on your own development car, or a car you get access to for a few weeks!

Start with the simple stuff, get it working right, and then slowly build upwards and outwards methodically, fixing problems as you go. Simply going straight for the high revs, big power etc etc, simply leaves you with 100's of potential problems with no obvious cause in your mind when something will invariably not work right.


As a rough guesstimate I'd say that tuning to say 5000rpm vs 4000rpm has about four times as many possible pitfalls and possible areas where things could be causing problems to worry about. It is sensible to isolate that step in the tuning process for obvious reasons.
If everything else works perfectly and then suddenly as you are adding fuelling at 4500rpm+ for big power, and you start to get faults, you can simply say to the customer you are reaching the limits of their hardware... since the rest of the rev range is otherwise running very very well!
You won't know that until you know the bit where it's easier to get it working right IS working right

Dave

[ginge191]

MrWhippy hock:

[silverzx]

MrWhippy hock:

His post pretty much sums up your B-Road killer.

[ginge191]

MrWhippy hock:

His post pretty much sums up your B-Road killer.

i didn't know he was still around in all honesty, their were people with whippy maps back on "OTHER" forums, then it all went quiet then BOOM! he shoots his load, to put it metaphorically..

top guy!