experience from others is 19PSI is the safe limit, you could go to 20, but with spiking it is probably better to set it to 19.

Anything above that the turbo has to work too hard so it is not very eficient (plus it will knacker it long term)

 

The other thing to bear in mind is that you'll get boost cut at around 20 psi on the standard map. One of the things Matt sorts out.

 

never did on mine actually.... been running 22 on the hybrid from as soon as it was fitted

 

Dont go any higher than 1.35 bar pal.
Fella's on here say that if you go higher than 20psi then you actually lose performance (i still havent got my head around that one yet)!!!!

 

Doesnt suprise me mickey, the turbo has a limit and on my setup at the time 20.5 psi produced less power then 19, not all cars are the same.

 

Ok, this is all getting me excited. I ran 20.6 psi at WGT to get 157 bhp. Now, I am running 19.5 psi and had my timing tweaked and eliminated the black smoke. I am wondering if I broke 160 bhp!

 

Ok, this is all getting me excited. I ran 20.6 psi at WGT to get 157 bhp. Now, I am running 19.5 psi and had my timing tweaked and eliminated the black smoke. I am wondering if I broke 160 bhp!

Get her dyno'd again.

Was your fuelling cut down in any way? Or could the maf have detected less airflow at full tilt?

 

The power level quoted will depend on the smoke you are willing to put up with to some extent, I've assumed a fairly low level of smoke in my calculations.

Whilst the above graph isn't the exact turbo we have (ours is a 1549 rather than a 1548, and I'm not sure what trim it is, it is very similar and won't be a mile out.

You can see that increasing the boost pressure (going up the graph) means that the turbo overspeeds and so you have reliability problems, 180,000rpm is rather fast in anyones books!

 

I find the jump in rpm quite interesting, from 13k to 153k, I assume that's the start of the end?

That said, I have actually had words with a turbo engineer who beleives the turbo can be toughened up, thrust bearings with finer tolerances, ball bearing cartridge and wheel clipping etc. Obviously this wouldn't affect the compressor map, but he reckons it would make a significant improvement and make it safe to run more boost.

Whats everyones thoughts on this? IMO - Whilst his intentions may be good, and most theories proved - we can't escape the compressor map.

Or on the other hand, whats wrong with 180000rpm if the turbos tougher?

Argh I don't know. They're a firm advertising on the net, seemed to know their stuff so I just rung them up for a little chat and they said they were pretty sure they could improve it.


Nobodies ever seen a stage one on a decent map, but we have seen a standard one do 150hp, so im not classing my turbo upgrade as great importance, as I hardly think my current one is being 'excercised' yet. A well built fuel and timing chip is much more important at this time, and is my first priority at the moment - but im keeping my eye open.

If the stage one is any better than a standard unit I want to be seeing 150+. I'l start thinking of turbo improvements when my dyno results actually reflect this.

So 'come on mista engineer, get it right! get it right!'

 

This is all very interesting. How much money are they talking about for strengthening the turbo. Any idea what types of psi increase are we talking about?

Im still with Mikey, in that how can a standard turbo at 21 psi loose performance, while a hybrid turbo increases the performance?

 

hi there i no this isnt to do with the thread but how much does is cost to get your car done on a dyno
cheers

 

different places charge different amounts.. but on average i would say £30-50

 

the hybrid has got larger turbines in both side (for a stage 2) and the shaft itself is strengthed iirc.
this means it can a) cope with spinning faster and b) provide more air at the same given PSI rating - at a cost of lag, but becuase it can go higher internally you can bosot the PSI even higher.

However it may be at a cost to the HG if you up the boost too high (i am speculating, but it seems to hold a certain sway in my mind due to 2 with high boost going at similar times)

Need to get my gf to do me some of the maths behind it - see if i can work out the actual numbers behind the PSI.... hmm

 

Thanks guys, this is all very interesting. I never looked into turbos too deeply, because it is a bit beyond my modifying ambitions.

Anyway, I found this nice intro to turbos

http://www.turboclub.com/turbotech/TurboFun1.htm

 

It's a good article, the author must be good with his analogies.

 

You can't "toughen" up a turbo so to speak, well not in terms of making it rotate faster. You can add a 360deg bearing which helps but doesn't alter the performance of the turbo at all it just makes it last longer!

As Dakta says, the stage 1 has a larger compressor map and so is different from the one I posted above. This essentially means it'll shift more air for a given turbo speed. Since the turbo speed is controlled by the exhaust turbine it means that the stage 1 will flow more air than the standard unit but will have similar spool characteristics. It'll spool slightly later but not much.

The stage 2 has a different compressor and exhaust turbine. This essentially means that it'll spool later but the exhaust side will be less restrictive at higher rpm's and so the power won't tail off as badly as the original unit. It'll make more power but will spool later in the rev range.

You can make a turbo spin faster than it is designed to, but it's life will be short and it may suffer a catastrophic failure. Hybrid turbos don't (or shouldn't) spin any faster than OE units. It is a materials property problem that limits the turbine speed rather than anything else.

 

You can't "toughen" up a turbo so to speak, well not in terms of making it rotate faster. You can add a 360deg bearing which helps but doesn't alter the performance of the turbo at all it just makes it last longer!

As Dakta says, the stage 1 has a larger compressor map and so is different from the one I posted above. This essentially means it'll shift more air for a given turbo speed. Since the turbo speed is controlled by the exhaust turbine it means that the stage 1 will flow more air than the standard unit but will have similar spool characteristics. It'll spool slightly later but not much.

The stage 2 has a different compressor and exhaust turbine. This essentially means that it'll spool later but the exhaust side will be less restrictive at higher rpm's and so the power won't tail off as badly as the original unit. It'll make more power but will spool later in the rev range.

You can make a turbo spin faster than it is designed to, but it's life will be short and it may suffer a catastrophic failure. Hybrid turbos don't (or shouldn't) spin any faster than OE units. It is a materials property problem that limits the turbine speed rather than anything else.

Interesting, the claims I heard were that it was shaft wobble that was a critical problem (hence attention to detail balancing). But still, what you say makes logical sense.

I still think we're giving turbos wayyyy too much attention. We know a map that is optimised and optimised, then optimised some more will push 150hp from a turbocharger that should (though I won't say 'is' until we have a compressor map available) be running at a considerably inefficient and heat-inducing speed.

I'm waiting for someone to apply an optimal map to the hybrid turbochargers. I've only seen it done once - and it got Mad 178hp, give or take dyno tolerances. Mark has got into 150+ territory before but I don't think his chips were ever 'right' if memory serves me well, and most other later cars dyno'd are running SDi injectors and are limited as a result.

I dont know what the stage one is capable of, but I bet its a little beyond 150...and it's the maps responsibility to do it, not the turbo's...boost is an ingredient, injection pump is an ingredient, the map is the method...

So really what I want to see, is results from cars running hybrid turbos, wingy injectors with Reidy software.

They always seem to get good figures.

 

Im starting to think that the SDI injectors will outperform the wingy injectors with the hybrids. My last RR result showed almost 160 bhp is achievable with the SDI injectors with very little fuel added. Matt is thinking that he can get around 180 bhp if he actually addes fuel the car can burn it.

Where the Wingy injectors simply dump masses amounts of fuel in and results in poor atomization and compressed unburnt fuel, I suspect that SDI injectors can achieve the same type of results as Mad's 178. bhp by using less fuel. In doing so, requires less air.

Roberto and Petes' cars are the ones to watch. They both will have similar setups, hybrid, FMIC and Reidy Remap, but differ in terms of injectors.

 

Im starting to think that the SDI injectors will outperform the wingy injectors with the hybrids. My last RR result showed almost 160 bhp is achievable with the SDI injectors with very little fuel added. Matt is thinking that he can get around 180 bhp if he actually addes fuel the car can burn it.

Where the Wingy injectors simply dump masses amounts of fuel in and results in poor atomization and compressed unburnt fuel, I suspect that SDI injectors can achieve the same type of results as Mad's 178. bhp by using less fuel. In doing so, requires less air.

Roberto and Petes' cars are the ones to watch. They both will have similar setups, hybrid, FMIC and Reidy Remap, but differ in terms of injectors.

I don't get that, okay so you're changing the manner fuel is delivered in a way that makes it easier to yield the energy contained in the fuel, but by limiting the quantity of fuel injected you actually limit the energy contained within the cylinder.

If the extra unburnt fuel consumed a large volume one could argue that it takes away displacement, but only a few grams get injected per stroke anyway, so in a 500 cubic-centimetre combustion chamber, i cant see the lack of unused yet potential energy making a difference for the better? Of course it'l give a cleaner burn, but simply because it's leaner?

Unless i've missed something?

My database does back you up, in that max boost seems to be the big factor with power, and injector nozzle size has more of an impact with peak torque, but I think you might be able to pin it down to the map.

For example sdi's and wingy injectors may have an overlap, wingy's working relaxed against hard pushed sdi's might both be good for 170hp, im not sure.

But I have heard that asking the fuel control collar to provide the actual quantity of fuel needed to release 150hp+, against sdi injectors does actually force it to come into contact with the stopper 'trench' on the plunger tiself, which wouldnt be good and could jam up the pump limiting its ability to alter fuel delivery at all.

finally on top of this, as there's a lot of untested theories in what I say, so I don't preach it as gospel, only as advisory, but the VAG crew on tdiclub actually see injector nozzle modificaitons as a very vital and necessary step to power. Just a thought.

 

Im not exactly sure the reason why unburnt fuel affects power output. I do very much recall that WGT told Luke to turn down the fueling (too much smoke) and this would increase performance. I probably is not a matter of displacement, but the high EGT and detonation?

 

Im not exactly sure the reason why unburnt fuel affects power output. I do very much recall that WGT told Luke to turn down the fueling (too much smoke) and this would increase performance. I probably is not a matter of displacement, but the high EGT and detonation?

Shouldn't detonate unless you've advanced the timing too much.

high temp I can beleive, but besides the dangers of damaging the turbo, cylinder head etc, it should actually help because nothing spools a turbo like hot air.

 

I may be way off of the mark, but i *think* that if there is too much unburnt fuel it effects the way that the gas is able to exit the engine and the way that the existing fuel is able to combust. (complete combustion vs incomplete - bunsen burner for example, twidle the air to make the gas burn hot and blue, or yellow and sooty)

going back to your comment before of plenty of air, and the way that the fuel itself can be burnt = the most power per gram of fuel injected.

On an unrelated note that might be the topic of a new thread but...

What i want to know is the maths behind the current engine & gasket and specifications etc.
how much does increasing the boost increase the actual cyclinder pressures.
How much does adding more fuel effect it - the additional volume of air with bigger turbo's etc.

Bigger turbo's allow higher RPM's as there is more air to help keep that fuel burning but as E_T_V said before the engine was only rated up to 4200 iirc, but i am still getting power in gear up to 4.5-5K - how much additional 'stress' is being generated by being run at these higher RPMs

If i can find the equations with enough constants\variables known i will throw the maths at my gf to see if i can get some actual answers out... there will be a fair numer of assumptions, and i think i will need to find out the flow rates\graphs of the stage 2 hybrid (and original and stage 1 if i can) etc before i even attempt to work things out...

 

well just to put it up again,
mk1 - 167bhp, 264ft/lb
but it was a lovely nice flat torque curve eg. 240@2k, 260@2.4k, 230@3.8k
this was not a reidy remap at this stage, so no advance timing, etc.
http://i41.photobucket.com/albums/e289/mrkstrlng/Scan10113.jpg

mk2 178bhp, 312 ft/lb

http://i41.photobucket.com/albums/e289/mrkstrlng/Scan10115.jpg
now if you look at the graph, i had problems with something effecting the engine around 2.6/2.8k, were it was peaking and dropping off, which i feel was the start of the hgf.

but back on topic, i do feel that a new set of sdi's would give very precise remapping with big mods. But if you want to break 190-200, ure foing to need wingy injectors. i do feel that itomisation is the key to it. As kris has said the vag boys get alot of joy from changing nozzles, and there is obviously someone out there that know wat its all about.

i have noticed on the dyno, that cars running too much fuelling, usually give low torque figures, power isnt really affected as much.

 

well just to put it up again,
mk1 - 167bhp, 264ft/lb
but it was a lovely nice flat torque curve eg. 240@2k, 260@2.4k, 230@3.8k
this was not a reidy remap at this stage, so no advance timing, etc.
http://i41.photobucket.com/albums/e289/mrkstrlng/Scan10113.jpg

mk2 178bhp, 312 ft/lb

http://i41.photobucket.com/albums/e289/mrkstrlng/Scan10115.jpg
now if you look at the graph, i had problems with something effecting the engine around 2.6/2.8k, were it was peaking and dropping off, which i feel was the start of the hgf.

but back on topic, i do feel that a new set of sdi's would give very precise remapping with big mods. But if you want to break 190-200, ure foing to need wingy injectors. i do feel that itomisation is the key to it. As kris has said the vag boys get alot of joy from changing nozzles, and there is obviously someone out there that know wat its all about.

i have noticed on the dyno, that cars running too much fuelling, usually give low torque figures, power isnt really affected as much.

I'l tell you something, it's a bloody shame you didn't do a run with your second (reidy) map with the stage one hybrid. Would have told us so much.

Did you put a thread up about your firsdt dyno run (170ps one?)

Unless I'm wrong, I think millhouse is getting his car dyno'd (tomorrow?) - now thats a car i've got my eye on and wish him well, because he's had a fair while to get his mapping right (obviously with your assistance) and he has a stage one turbo, so I think good figures could be his way.

Though I do think he should run with wingy injectors...

 

Ok, I came across this graph: http://www.bycosin.se/comb_chart.htm


The wingy injectors have larger nozzle openings and this in turn, produces larger fuel drop size and poor atomization?

From the graph, we see that larger fuel drops have much longer combustion, heating and ignition time.

What ends up happening is the larger fuel drops do not completely burn and creating soot.

Although efficiency is easly explained, I am still stuck on max power output.

On a side note: I do have my set of hybrid injectors that atomize the fuel very well and they have brand new first stages that have been test and calibrated. I know with this injectors, if you get the first stages right, it does not matter what happen in the second stage. So what I am thinking is that I can but these new 1st stages onto my sdi 2nd stages and have tested and calibrated set of sdi injectors. Would this work?

The other option is to just drop off the sdi injectors to my diesel mechanic, but he will charge me £200 and I dont think I would really see any benefits.

 

Ok, I came across this graph: http://www.bycosin.se/comb_chart.htm


The wingy injectors have larger nozzle openings and this in turn, produces larger fuel drop size and poor atomization?

From the graph, we see that larger fuel drops have much longer combustion, heating and ignition time.

What ends up happening is the larger fuel drops do not completely burn and creating soot.

Although efficiency is easly explained, I am still stuck on max power output.

On a side note: I do have my set of hybrid injectors that atomize the fuel very well and they have brand new first stages that have been test and calibrated. I know with this injectors, if you get the first stages right, it does not matter what happen in the second stage. So what I am thinking is that I can but these new 1st stages onto my sdi 2nd stages and have tested and calibrated set of sdi injectors. Would this work?

The other option is to just drop off the sdi injectors to my diesel mechanic, but he will charge me £200 and I dont think I would really see any benefits.

Wingy injectors indeed produce larger fuel droplets and so take longer to burn. Cruicially you'll also notice that they take longer to heat before they burn too. This means that using them you'll need the timing advanced so that the combustion event starts at the same time as with normal injectors. (Otherwise you are effectively retarding the combustion timing using larger nozzles). If you don't, you get more smoke and lower than expected power figures. Larger droplets also take longer to burn so you'll get more smoke anyway particularly at the top end of the rev range where the time for combustion is short. Obviously you can offset this by adding more air but it'll never fully cure the problem.

This is why modern dervs are comon rail as they can use finer and finer droplet sizes which burn faster with less smoke which gives more power and more efficiency.

I'm still a little confused as to what Dr.Evo's injectors actually are, as I was led to believe that the only difference between the VP37 and the VP30 injectors was the nozzle and the opening pressure for the primary stage. The secondary stage was the same, (I think I got this info from rover literature but don't quote me on that).

Are you running SDi nozzles or the original 25/45 etc ones?

 

its def a quick car, and like i say the mid range torque is great. Hopefully we can sort the water problem out and get it on the dyno. Then we can fine tune the map, and see wat we can get out of it. Just hope the transmission can cope.

 

I know this is all theory Dan, but on tdiclub, the general perception is that for every 1mm increase in plunger diameter, it's the equivelant of you going up a nozzle size as far as fuel quantity injected goes.

This is remniscient of the plan I had a while back, bigger pump, smaller injectors. What do you think, go back to sdi injectors and their spray pattern (and droplet size too) with a pump that shoves in more?

And don't forget, the turbo needs energy to run, and since the only energy source is wasted energy, an efficient engine will rob the turbo of this. Hence the overfuelling actually been a good thing for a turbo in the performance respect, but also pretty much is a death warrant in terms of reliability.

 

Thanks for the clarification as well as understanding the difference with the commong rail diesels.

They hybrid injectors are simply SDI first stages popped on MG ZR second stage, which have a break pressure of 210 psi.