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Just saw this thread now. It escalated quickly lol
Imi's and Ozzy's car's both perform very well. They were almost getting back to back identical results all day long, so their packages were definitely reliable.
One thing I need to clarify is that I had purchased a set of what I thought were "68MM" turbo's from the forum, and was running them in that Vmax event.
However Once the turbo's were removed to fit the ES850 kit, it turned out that they were stock sized wheels, just in billet form. 60-130's were high 6's on that setup and Emre was expecting quicker if they had been true 68mm's.
The seller who I bought them from wasn't aware of this, So it turns out I was just running stock sized GT2 turbo's at that event.
I would expect a set of 68's to perform better than the turbo's I had installed for sure.
However having said that, I wouldn't ever go with a hybrid VTG setup again over a GT setup.
Cost wise there isn't a huge difference, and performance overall is much better anyhow.
That said for the guys using VTG's, Champions turbo's do yield good results from the Vbox data I have seen.
From a personal point of view, I think 60-130 is the most useable day to day data that verifies actual performance.
0-300 is good of course, however there are too many factors that affect a run. Safety and conditions being one of them.
I do genuinely believe you do not have to sacrifice top end with the right tune and setup on a VTG kit. My own car with stock GT2 turbo's proved that to be the case, the 60-130's were quicker without any issues uptop.
Emre did do a lot of work on the tune though. He also generally tunes all his cars for 60-130mph as well as 200-300kmh so has good experience in getting the overall setup right.
My ES850 kit is heads above what I expected and performs just as good as any VTG kit spool wise, so personally my opinion would be to stick to GT turbo's for big power.
Very diplomatic Amir!! We run our cars back to back over 50 runs at well over 200mph our 9e28 have logged and run 205mph within 1.3 miles and this chump Nick who's never run his car above 180mph thinks we are under performing lol just beggars belief.
Completely agree on the GT vs VTG and I'd go the same route as you next but on a fully built 3.9 engine similar to Toby's.
Just saw this thread now. It escalated quickly lol
Imi's and Ozzy's car's both perform very well. They were almost getting back to back identical results all day long, so their packages were definitely reliable.
One thing I need to clarify is that I had purchased a set of what I thought were "68MM" turbo's from the forum, and was running them in that Vmax event.
However Once the turbo's were removed to fit the ES850 kit, it turned out that they were stock sized wheels, just in billet form. 60-130's were high 6's on that setup and Emre was expecting quicker if they had been true 68mm's.
The seller who I bought them from wasn't aware of this, So it turns out I was just running stock sized GT2 turbo's at that event.
I would expect a set of 68's to perform better than the turbo's I had installed for sure.
However having said that, I wouldn't ever go with a hybrid VTG setup again over a GT setup.
Cost wise there isn't a huge difference, and performance overall is much better anyhow.
That said for the guys using VTG's, Champions turbo's do yield good results from the Vbox data I have seen.
From a personal point of view, I think 60-130 is the most useable day to day data that verifies actual performance.
0-300 is good of course, however there are too many factors that affect a run. Safety and conditions being one of them.
I do genuinely believe you do not have to sacrifice top end with the right tune and setup on a VTG kit. My own car with stock GT2 turbo's proved that to be the case, the 60-130's were quicker without any issues uptop.
Emre did do a lot of work on the tune though. He also generally tunes all his cars for 60-130mph as well as 200-300kmh so has good experience in getting the overall setup right.
My ES850 kit is heads above what I expected and performs just as good as any VTG kit spool wise, so personally my opinion would be to stick to GT turbo's for big power.
60 to 130s as base comparison are good but if one is running a TiP that has a tcu upgrade with shift point times decreased ( we can do that lol) then sure it will run faster then someone trying to shift unless ur reality good. But I've hardly seen fast 60 to 130s on any vtgs on a Manual 997.1. Every wonder why ? Even the record 1/4 miles times are all done on either trips or now sequential boxes.
I'm just asking not starting anything arguments. I can make the tcu really happy and shave off some decent time just by re programming it.
Markski
Yet none of Champions 68mm vtgs with monster tunes have run and logged 0-300kph. And we are the ones under performing lol.
What a complete and utter see you next Tuesday.
There aren't too many opportunities in North America to get to 300km/hr. There are some closed track events on airport runways etc... but even then I'm not sure how fast a driver could go.
I have taken my car with the 68s to Mosport which is a fairly fast track. Repeatedly thrashed the car up to about 250km/hr and it has performed superbly and with no drama.
My ES850 kit is heads above what I expected and performs just as good as any VTG kit spool wise, so personally my opinion would be to stick to GT turbo's for big power.
I'm surprised to hear your GT based kit spools as well as a vtg - everyone else I've spoken with that has GTs and alpha 30s says the spool is not as good. The alpha 28s are early spoolers though.
There aren't too many opportunities in North America to get to 300km/hr. There are some closed track events on airport runways etc... but even then I'm not sure how fast a driver could go.
I have taken my car with the 68s to Mosport which is a fairly fast track. Repeatedly thrashed the car up to about 250km/hr and it has performed superbly and with no drama.
Running up to 250 kph ish not an issue for VTGS. It's 300kph plus when the problems start occurring. The big boys are running circa 370kph at VMAX. In fact it's the 9e XX that has run this speed and nothing including Bugatti, La F, 918, and P1 can get close to that sort of top speed. VTGs in my view would just melt the engine due to the back pressure and heat generated at these sort of speeds. Pretty sure 9e XX still holds the VMAX record to this day at 229mph and the same car has run 250mph on the autobahn. Not bad for guys that do not know what they're doing lol!!
I was under the same impression, but after speaking with Emre, he advised it's not always the case. Hence why I went for the ES850 kit, which was designed for a street car.
It spools very very well. As I said earlier a lot of it is down to getting the overall setup right.
Intake pipework, intercoolers, as well as IMO most importantly the tune, all make a huge difference.
Emre logs and logged with Vbox data as well as durametric until I was happy with the car.
My GT based setup spools as quick as a hybrid based VTG setup.
60-100 in 3rd is 2.6. That's without brake boosting and literally just planting it at 50mph. 60-130 in just 4th gear was 6.5. And 5.7 for 3-4th gear.
It should be a lot quicker on an E85 or race fuel map.
VTG's is where I wanted to stay and mainly due to the charchteristics of the power delivery, but I can honestly say I wouldn't go hybrid VTG again when a GT kit performs just as good down low but better uptop.
60-100 in 2.6 on pumpgas is awesome. I did that once with my 68s but it was pulling a lot of timing and not a repeatable result.
Glad to hear your car spools like a beast and delivers the goods.
I have 3rd gear logs. The 4th gear logs are just partial - that's getting into "go directly to jail" territory. I have some 4th gear logs from the track last year but it was a different version of the tune and stock injectors. Injector duty cycle was waaaay up there. Did you want the 3rd gear logs? Or I could wait till I go to the track in the fall and get 4th gear logs.
Since there isnt any location info in the logs there is nothing to worry about, all my 4th gear logging is done in mexico or russia
A 3rd gear would be of interest as well, but the load is clearly higher in 4th.
60-130 is a good measure and of course whilst it still attracts attention certainly not as much as a launch to 300 plus kph.
The facts are this and it applies to any tuner on vtgs - take the car at 1.2 bar and run to 320kph plus from a standing start and I will wager it will be quicker than doing an identical run at 1.5 bar - it is simply down to the increased back pressure and resulting increase in temps from these standing starts. I have the datalogs to prove - it is the same on a standard VTG as well.
But in those cases take the 1.5 bar run for a dedicated 60-130 and it will be much faster - it doesn't have an opportunity to build sufficient back pressure. And this is why there is a difference with dyno as well - there is no enough load.
Now if you leave all the controls in the dme, the increase in back pressure will be taken care of by chucking in fuel to cool the engine and reducing boost. If you remove those then you might be quicker but you run the risk.
The gt2rs as standard only runs 570ps above certain temps - that is nearly 50ps down on standard - even head of porsche engineering admits this happens.
And with vtgs what you cannot do is say add together the 0-100, 200-300kph runs to get a time either - it is not the same as a straight 0-300kph run.
Non vtgs can still suffer with back pressure but generally no where near as much.
One way to reduce the back pressure is run less boost or build the engine out and lower compression so the engine can breath better.
We are fortunate to have venues in the UK that allow us to do these tests.
One very interesting test would be this:
-remove one of the EGT sensors
-attach there a pipe (40-50 cm) + about a one meter of temperature-resistant hose + a pressure sensor that's good up to 4 bar ( 1 bar ambient + 3 bat overpressure)
-go and floor it with datalogs...
That would answer all possible backpressure questions.
Someone really interested in finding out things would do a permanent isntallation of (back)pressure sensor, it just needs some exhaust manifold drilling and welding.
Independent of turbine model ( conventional or with adjustable guide vanes) at a certain point it is not capable of flowing more and then the backpressure will increase. Period. With increasing EGT. Period. I'm really astonished if any reputable tuner hasn't done this logging yet!?
Now it's true that VGT's turbines are more flexible that conventional turbo's but they're really efficient only at 60% guide vane opening. Above and under that effiency drops, flow's more restricted.
I'm pretty sure that Porsche has spec'd their turbos to this optimal area. I've only seen partial maps of .7.1 VGTs' programming, but in those screencaptures opening percentages have been in that very area.
In addition turbine flow calculations are a bit more difficult than compressors', one needs to now a bunch of variables to get reliable results. To make things even more difficult Borg Warner has not released (almost) any data about BV50's used in Porsches. Smaller BV40's for certain mid-size diesels are slightly better covered. Big lines can be found there.
Comparison of Fixed Geometry (BorgWarner KP39) and Variable Geometry (BorgWarner BV40) Mass Flow vs. Pressure Ratio:
Effect of variable geometry turbine nozzle opening and blade speed ratio on turbine efficiency:
Managed to find some time to do a better test of VTGs in terms of impact of 60-130 and 0-300kph etc and the relationship to back pressures/IATs.
In the boost comparison chart you can see the previous boost map - 1.2 bar tailing off to 1 bar in higher load. These are 66mm VTGs but frankly it doesn't matter which VTGs, the concept is the same. We ran the car from 0 miles per hour, shifting at the same time on same stretch of road within 30 minutes of each other. The only change was to the mapping in terms of load etc. The red line takes a different approach - run 1.2 bar and ramp to 1.4 bar at peak.
So what was the results - same set up 60-130mph was over 1 second quicker 6.7 versus 7.95, logical of course - you make more power to run faster times. But, here is the consequence, higher IATs. Car runs GT2RS intercoolers btw. So over 160kph (100mph) you can see the impact as soon as you get into 3rd gear the backpressure builds and rising IATs. These get incrementally greater the faster you go.
If you ran 1.5-1.6 bar the situation will be worse - quicker 60-130mph but press on and afterwards you are going to have the DME cooling the car down, chucking in fuel and retardation.
The interesting thing in Kens post above is that 9e estimate the above package at 640 PS or 631bhp although they do not quote bhp numbers. Many members on here would be quoting in excess of 700bhp + on the above 60-130 mph time irrespective of if the car is slower to 300kph than say an 8 sec 60-130mph car.
The interesting thing in Kens post above is that 9e estimate the above package at 640 PS or 631bhp although they do not quote bhp numbers. Many members on here would be quoting in excess of 700bhp + on the above 60-130 mph time irrespective of if the car is slower to 300kph than say an 8 sec 60-130mph car.
That's the reason I leaved the vtgs, I wanted the butter and the money for the butter!
That's the reason I leaved the vtgs, I wanted the butter and the money for the butter!
FROM THE MAESTRO HIMSELF RE VTG ON ANOTHER THREAD - WHAT DOES HE KNOW HE ONLY HOLDS A FEW WORLD RECORDS LOL
Emre@Esmotor
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Hi guys,
If you don't change the VTG turbine mechanisim, it is impossible to get full benefit of the
upgraded compressor wheel while going up to 300 km/h, and nobody touched the turbine side yet, there is a limitation with the backpressure and heat with bigger VTGs.
So, please don't turn this topic into VTG vs Garrett turbo debate and keep the focus on Amir's build. LoL
Cheers,
Emre
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997TT - Home of the worlds quickest Porsches
1/4 mile: 8.81 @ 264 km/h
100-200km/h: 2.80 sec
200-300km/h: 5.43 sec
60-130mph: 3.29 sec
100-150mph: 3.11 sec
