Hybrid turbo..

[Mr Whippy]

Haha

It was a bit of a verbal ejaculation hehe.



Show me a good stage 3 HDi and I'll happily eat my words though

If the hardware isn't right, the software will never work right. It takes a lot of work and time to get it right.

Only stg3 cars where significant time, effort and thus money have been invested, do things work properly.

Ie, Pete's VNT HDi seems to do everything a normal HDi does, just 2 X as much... no weird behaviours, bad idle, just solid torque and power all over.


For all the fannying around, Bryn's car made 173bhp on his hybrid, fmic and exhaust mods alone all those years back. It was on a remap bodged to run meth too, not an FMIC... if he'd even bothered to exhaust (no pun intended) the potential that set up had it'd have probably made a good solid 275lbft and 180bhp, simply a hybrid turbo on an otherwise usual FMIC 306 HDi. The power was a bit further up the revs.

But get a GOOD hybrid turbo on there and you'd probably have 180bhp combined with more like 300lbft and near the driveability of a K03 HDi90!


Unfortunately it seems there has been a black hole of people exploring that area of tuning... always wanting to buy a camshaft or fit a light flywheel or a fancy manifold or new con-rods... anything but the next logical step of hardware improvements to alleviate the obvious bottleneck of the standard car... the ducks arse turbine outlet!


XUD's are a different beast though. Tuning them is very much a turn a screw and see. Grind something away and see. Very fun in some ways, and almost more intuitive than HDi tuning beyond a certain point!


Dave

[Ruan]

The turbine side is absolutely essential on Diesels... As standard they were crap...

I'll completely agree though, people need to stop getting distracted by other modifications (which are usually the for the petrol ilk), just whack on a better turbocharger and get the mapping sorted... IMHO the stock turbocharger housings are too small, no point in trying to fit mahoosive turbines in them, you end up screwing the A/R so much, it becomes pointless, the housings are as important as the turbocharger itself. Look at a VNT turbo, effectively a variable housing, they make a MASSIVE difference.

Not to mention the problems that inevitably come with a small turbine - Hydro Lifters.

All a HDi needs is a big turbo, a GOOD intercooler setup, no pikey bodges and a clutch... Once you've exhausted that, then maybe a bigger pump and nozzles - but the mapping is essential.

Not my cup of tea might I add - I don't give a crap about a lumpy, rash, rattly idle, a bit of a dead spot at about 1800rpm... Problem with a HDi, if you've got that going on, you've got all sorts of other issues that are being affected by that one thing... They're so intertwined...

[con67]

If you want revs your better with idi, the di engines ve drops off more sharply the idi above 3k rpm due to it relying on swirl generated by the shape of the ports which diminishes fast higher up the range, some of the vag men have really cleverly ported thier heads to achieve the big rpms so alot of it is in the head not diesel combustion. The idi doesnt have this 'problem' and has ram type port with seperate swirl chambers.
As for bigger turbos being 'undrivable' I dont buy this at all, with my big turbo fitted, then removed and the hotside hogged out the car was far more drivable at low rpm than with the k03!!! Wee had a straight d 306 at the time and with no boost at all below 2.5k and a longer gearbox the turbo car off boost still would have roasted the straight d, imo it was more 'drivable' than laggy as fook k03 (lag not threshold the k03 engine bogged down and went slower if floored below 2 grand).
Of course 'drivability' is just an opinion/preference and doesnt actually exist, maybe if this idea was dropped manufacturers would make proper diesels again.

[Mr Whippy]

I won't say big turbos are more laggy, but it's often not exactly desirable to have a massive wodge of torque low down anyway.

I actually prefer the rainbow output of a 'proper' turbo diesel.

VNT flattens things out and lets you get massive peaks low down, but the result is a curve which isn't so sweet to drive. It's harder to anticipate when you are 'driving' the car (ie, enjoying a back-road blast)...
My FMIC HDi with GT15 spooled up really low down and went like a rocket, but I'd have given some of that up for just being a bit smoother and easier on the clutch/drivetrain/less likely to spin up, and gone for a bit more at the top end.

The shape of the curve is just as important in my view, balancing torque with power to give a rewarding run through the revs. Just going for the most you can everywhere looks good on a before/after dyno, but the result when driving is often just unrewarding.

Add too much torque down low and it makes the top end even less inspiring than it already is in a diesel.


Yes the specs of VNT appeal on paper and on a dyno, but I think I'd find myself tuning out half of the 'benefits' it offers just to make the delivery feel a bit smoother and peakier!

Getting the biggest numbers in my view is missing the best point of making cars faster, which should be all about appealing to what drivers really want. And that is a bigger grin on their face after going WOT from the lights, or when guiding their car around a long sweeper. Neither requires more power, but both require a characterful interesting delivery and good response


And that is where you are right Ruan, the Td when tuned has so much character. The way it makes it's torque is just as important as how much it makes.
I'd happily give up VNT for the cost/hassle/benefits I don't want, to retain benefits I do want in a good old naturally wastegated turbo delivery... I'm sure on the road, track or drag strip, a 180bhp VNT and a 180bhp hybrid would be inseparable anyway... only on the dyno would you notice... and on your wallet

Dave

[Ruan]

In complete fairness, VNTs aren't all about delivering it all down low... It gives you the ability if you want to, but it's more about the response...

My car will build 10psi literally INSTANTLY from about 1400rpm... Then from 2k onwards it's at full boost... Doesn't mean you have to give it all the fuel there... It's just that rather than waiting for the turbo, you can map it how you want the power to be delivered, but you aren't waiting for that power delivery to come - if you catch my drift?

You can be mid way round a corner, lift and drop boost, then go back on the power, it'll take SO much less time for the turbo to spin back up in comparison to a normal WG turbo, that's where IMO you really notice it.

You can create such a FLAT powercurve, bring in the torque super fast, but limit it, but keep it flat all the way to the redline... That's the entire point... IMO they're totally worth the money for the increase in response.

[Atterz]

When are you popping up to fit one to my DT then? And help me change a Rallye gearbox .

[Ruan]

Whenever you say buddy!

Give me a date, I'll be there, long as I'm not working!

[Atterz]

You a legend Ill aim off for after summer now, will ring you Sunday probably if your going to be free.

Anyway back on topic!

[Jonny81191]

Dave, I'm going to need to chat to you about mapping. I know this is very long term, but I want to do things properly, not just bolt on any old blower and see what happens..

And that means research. It's amazing how much more I understand when I read this back now

[Mr Whippy]

Me Dave? Or another Dave?

I'm probably not your man to talk to about the right turbo, Pete (TB205) seems to know a few things if you want to go into the realm of a VNT as he ran a 200bhp VNT HDi, ooooor, Ruan or someone if you want to go for an boost actuated turbo that is also modern, and fits easily

I've always been one for doing jobs right, and I wouldn't buy anything that wasn't either recon with warranty or new. Thus for me the next step after FMIC would be a hybridised rebuilt k03 and I'm certain with that 180bhp would be possible. Possibly even 190bhp with the very best exhaust (just something that looks like a drainpipe, not something naff with kinky bends) and a fit engine generally.

Torque isn't as high as it could be, possibly it's a touch lower at lower rpm, but that makes for an easier life on the HP pump, so you can probably run standard everything else and get good torque and good power!


Beyond that I'd go VNT like Pete did, but to really make the most of that it's an upgrade pump (make sure it's recon or very good, otherwise it's no better than a good standard one), an upgraded rail sensor, an upgraded clutch to take the big low-end torque, alternate setup for ECU/solenoids to run VNT, a VNT turbo (again, make sure it's very good or recon to assure it will work as expected), and so on... you might even want to re-tip injectors to make life easy at around 205-210bhp.


That is my 2 pence any way.

Going big on torque is why soooo many cars on here both need fancy clutches and also suffer with p0230. Pump is spinning slowly and making BIG injections through small injectors so you need BIG rail pressure too... arghhhh!

Better as a next-step after FMIC to rev more (not 5000rpm, more like making peak power at 4000rpm rather than 3250rpm) with a bigger turbo, retain moderate mid-range torque.

Then if your wallet is liking the idea of a step up from 250lbft/185bhp you can sink £1500 more for turbo, mapping, solenoids, clutch, injectors, pump, rail sensor etc to get another 20bhp and 70lbft.


No doubt Pete's car will have been rather amazing, but he spent a lot of time getting it perfect, and that takes money too.

From experience I can appreciate both ends of the spectrum. Any HDi with FMIC is faster than it needs to be, so beyond a certain point it becomes a personal preference rather than right or wrong.

All those nutters with 1.9Td's that rev hard and make mega power can't be wrong and represent one end of the spectrum, while those with VAG's that make peak power from 2500rpm to 5000rpm that are devastatingly fast, but about as much fun as a train to drive (imo), clearly have something they like!

Dave

[Jonny81191]

Hmm..

Will continue thinking on this, and collecting shiny bits of course!

All I really need now is:

A clutch,
Injectors,
I want to stay with a wastegate turbo, and that's basically sorted,
Obviously a decent map (this is what I want to talk to mr whippy on, I'll PM you at some point)
And I'm looking into head work and maybe an overbore, but i'll stay deliberately vague on that for the time being..

[Mr Whippy]

Whatever you do, do it in stages.

Do it in steps and get each step right, mapped up properly, then move on to the next one. If you hit problems then you can quickly isolate the problem hardware or remapping change.
I'm not sure on other tuners but it's much easier for me to charge once and offer support through your project over as long as you need to do it, than try do everything in one massive and messy step under the assumption that it'll be cheaper to remap in one go.


I've seen a lot of mega projects go straight for the end result and they just don't offer the results expected because it's just not feasible to remap these kinds of cars on a budget of both money AND time...

I suppose it's like the cost/quality/time triangle.

If you want quality at low cost it'll take time... if you want quality in little time it'll cost a lot... if you want something at low cost and quickly, quality will suffer.

We have all the time in the world so to speak, if the re-mapper offers a cost for the whole project, and the tuner is happy to work slowly, so we can get quality and at a low cost


Dave

[Jonny81191]

Completely agree.

I'm just ordering a cambelt kit, at which point the R70 is going on, then i'll go from there...

[pugbug]

I have a stage3 HDI with a GT17 hybrid turbo, it's modified all round, brakes, suspension, cooling, etc... I HATE driving it in the city, the turbo comes in after 2.2K and it's pretty jerky to drive, I much prefer my stage1 with a GT15, no turbo lag, although slower more effortless to drive. The stage3 on the motorway, however is phenomenal, overtaking ability is excellent and always begs for spirited driving

[Poodle]

You really need to get a project thread up dude!