Finally got the 3.0 turbo right!
05-23-2013, 07:36 AM
#31
Burning Brakes
Thread Starter
It seems to me that Tom's posted log was obtained on the road, though?
Would be interesting to get some curves obtained from using a driftbox or the likes when driving on the road, as you should then be having a slightly higher torque peak on the road that on the dyno.
I'm mostly interested in the 100-200kph time, it should tell most how the car performs.
Would be interesting to get some curves obtained from using a driftbox or the likes when driving on the road, as you should then be having a slightly higher torque peak on the road that on the dyno.
I'm mostly interested in the 100-200kph time, it should tell most how the car performs.
05-23-2013, 07:43 AM
#32
Burning Brakes
Thread Starter
Nick, congrats and cheers on getting it sorted -- looks like you have a real stump-puller there, which must be a blast to drive. Looks like the boost is trailing off toward redline -- trust the wastegate is fresh and that's just the turbo trying to keep up with big 3 liter lungs? I'm still perplexed by your experience with the Vitesse Stage 5 turbo. Mine is circa 2006 if memory serves and as I've posted before makes 14.5psi at 3000 (see log below) and made 500rwhp on a dynojet (at higher boost, but with more to give). Maybe yours was older or not working right in some way? Either way, happy you found one you like and can finally enjoy the car the way it was built to be enjoyed...
05-23-2013, 08:21 AM
#34
Rennlist Member
Having never measured this to any degree I can't state with any surety but I'd be inclined to agree with Pauly in terms of not losing too much, if any tangible spool time due to larger I/C. I'm sure in absolute terms you must, but then compared to what, stock? Perhaps your I/C has better flow against some old clogged stock I/C anyway Nick in which case it minimises this. I think once the motor displaces positive pressure it circulates very quickly...well that's my totally subjective theory anyway. :-) Look at those guys running turbos right down near the rear muffler. They should experience extremely laggy response shouldn't they?
As for the gear/final drive ratio conundrum...I am still on the fence about this. We know that a longer gear will allow the turbo to load more and probably move into it's preferred efficiency area, but maybe the stock shorter gearing is more commonly in the 'meat' of the powerband which leads to faster acceleration. I would think that it also depends on where and how you drive. On the track some would argue that having longer gearing would result in greater torque and of course less gear changes and gear changes cost time (unless you're one of those lucky bastards who have pneumatically operated paddle shift sequential gizmotrons !)...where others would say that they can access the powerband more readily with a shorter set and also perhaps be in a more suitable rpm range for particular parts of the track. I didn't find the 6 speed too short for the brief time I had it on the last iteration of my car...but perhaps it might be all wrong in the (hopefully) not too distant future.
As for the gear/final drive ratio conundrum...I am still on the fence about this. We know that a longer gear will allow the turbo to load more and probably move into it's preferred efficiency area, but maybe the stock shorter gearing is more commonly in the 'meat' of the powerband which leads to faster acceleration. I would think that it also depends on where and how you drive. On the track some would argue that having longer gearing would result in greater torque and of course less gear changes and gear changes cost time (unless you're one of those lucky bastards who have pneumatically operated paddle shift sequential gizmotrons !)...where others would say that they can access the powerband more readily with a shorter set and also perhaps be in a more suitable rpm range for particular parts of the track. I didn't find the 6 speed too short for the brief time I had it on the last iteration of my car...but perhaps it might be all wrong in the (hopefully) not too distant future.
05-23-2013, 08:36 AM
#35
Nordschleife Master
Yes, if you calculate how much air that goes through the engine you will find that a few liters here and there in the IC piping etc is very negligible 
05-23-2013, 09:22 AM
#36
Burning Brakes
Thread Starter
Every little counts. We are only talking 200 - 300 rpm so 50rpm of that is still 15 - 20%. The effect of larger pipes and intercoolers is well documented. My air intake is also less than ideal but I need to work on this. I am not saying it is a big deal just a contributing factor.
05-23-2013, 09:24 AM
#37
Burning Brakes
Thread Starter
Having never measured this to any degree I can't state with any surety but I'd be inclined to agree with Pauly in terms of not losing too much, if any tangible spool time due to larger I/C. I'm sure in absolute terms you must, but then compared to what, stock? Perhaps your I/C has better flow against some old clogged stock I/C anyway Nick in which case it minimises this. I think once the motor displaces positive pressure it circulates very quickly...well that's my totally subjective theory anyway. :-) Look at those guys running turbos right down near the rear muffler. They should experience extremely laggy response shouldn't they?
As for the gear/final drive ratio conundrum...I am still on the fence about this. We know that a longer gear will allow the turbo to load more and probably move into it's preferred efficiency area, but maybe the stock shorter gearing is more commonly in the 'meat' of the powerband which leads to faster acceleration. I would think that it also depends on where and how you drive. On the track some would argue that having longer gearing would result in greater torque and of course less gear changes and gear changes cost time (unless you're one of those lucky bastards who have pneumatically operated paddle shift sequential gizmotrons !)...where others would say that they can access the powerband more readily with a shorter set and also perhaps be in a more suitable rpm range for particular parts of the track. I didn't find the 6 speed too short for the brief time I had it on the last iteration of my car...but perhaps it might be all wrong in the (hopefully) not too distant future.
As for the gear/final drive ratio conundrum...I am still on the fence about this. We know that a longer gear will allow the turbo to load more and probably move into it's preferred efficiency area, but maybe the stock shorter gearing is more commonly in the 'meat' of the powerband which leads to faster acceleration. I would think that it also depends on where and how you drive. On the track some would argue that having longer gearing would result in greater torque and of course less gear changes and gear changes cost time (unless you're one of those lucky bastards who have pneumatically operated paddle shift sequential gizmotrons !)...where others would say that they can access the powerband more readily with a shorter set and also perhaps be in a more suitable rpm range for particular parts of the track. I didn't find the 6 speed too short for the brief time I had it on the last iteration of my car...but perhaps it might be all wrong in the (hopefully) not too distant future.
05-23-2013, 09:29 AM
#38
Rennlist Member
Lol...and I always wanted the 6 speed as the 5 speed with the S2 ring and pinion REALLY needs another gear on the Motorway!! I'm not even sure that an expensive custom ring and pinion for the 6 speed would solve some of the issues. Probably need to go the even more costly aftermarket cogs although maybe 4-6 might suffice? Are the 968 gears interchangeable with the G50 sets?
05-23-2013, 10:47 AM
#40
Burning Brakes
Thread Starter
Lol...and I always wanted the 6 speed as the 5 speed with the S2 ring and pinion REALLY needs another gear on the Motorway!! I'm not even sure that an expensive custom ring and pinion for the 6 speed would solve some of the issues. Probably need to go the even more costly aftermarket cogs although maybe 4-6 might suffice? Are the 968 gears interchangeable with the G50 sets?
08-12-2015, 05:56 PM
#41
Burning Brakes
Thread Starter
A brief update on my car....
More trials and tribulations after the last update - turns out the head gasket was weakened at the dyno and the coolant system was blowing out some coolant at a couple of the hose connections. So I did the HG last year and got the car up and running again.
Before I did the HG and after a fair amount of head scratching and reading I decided to replace the number 8 hotside housing which came with Thoms old turbo for the number 10 housing taken off my old VR5. I knew they would fit as both turbine wheels where the same. The reasons for doing this swap were twofold - the engine would not make power at the top end with any more boost above 0.9 bar and the head gasket went on the dyno so both pointed to an overly restrictive hotside. I could either change the whole turbo.....again or just try the larger housing to take the pressure off a little.
So far things have been good. The larger housing works well, the car feels better up to the top end and the HG is holding well as are the coolant temps.
Next step is to fix the annoying hot start issue I have had for years which seems to be a fuel pressure drop off problem. I have fitted a check valve in the fuel lines as the 044 pump does not have one fitted due to lack of room in the pump location. However the Fuel Lab regulator I have is also letting pressure drain off too fast so that is getting replaced with an SX regulator that is supposed to hold pressure for longer after shutdown. Fingers crossed this does the trick.
Next step is suspension. The KW V3 which was used when I bought it is past its best and the car is not very confidence inspiring, rather than getting another KW kit or getting it rebuilt I am considering AST coilovers as they seem to be the closest thing to PSS9/ PSS10 that I can find and have a good reputation with a lot of the BMW guys as a streetable coilover kit that works well at the track. I will also replace the control arms with the Hartech motorsport versions of the genuine arms at the same time and fit the M030 spindles I have been sitting on to eliminate the brake adaptors and get a little clearance back between the tie rod ends. When that is all done I might finally consider fitting my freshly re-finished Turbo 3.6 Speedline wheels!
More trials and tribulations after the last update - turns out the head gasket was weakened at the dyno and the coolant system was blowing out some coolant at a couple of the hose connections. So I did the HG last year and got the car up and running again.
Before I did the HG and after a fair amount of head scratching and reading I decided to replace the number 8 hotside housing which came with Thoms old turbo for the number 10 housing taken off my old VR5. I knew they would fit as both turbine wheels where the same. The reasons for doing this swap were twofold - the engine would not make power at the top end with any more boost above 0.9 bar and the head gasket went on the dyno so both pointed to an overly restrictive hotside. I could either change the whole turbo.....again or just try the larger housing to take the pressure off a little.
So far things have been good. The larger housing works well, the car feels better up to the top end and the HG is holding well as are the coolant temps.
Next step is to fix the annoying hot start issue I have had for years which seems to be a fuel pressure drop off problem. I have fitted a check valve in the fuel lines as the 044 pump does not have one fitted due to lack of room in the pump location. However the Fuel Lab regulator I have is also letting pressure drain off too fast so that is getting replaced with an SX regulator that is supposed to hold pressure for longer after shutdown. Fingers crossed this does the trick.
Next step is suspension. The KW V3 which was used when I bought it is past its best and the car is not very confidence inspiring, rather than getting another KW kit or getting it rebuilt I am considering AST coilovers as they seem to be the closest thing to PSS9/ PSS10 that I can find and have a good reputation with a lot of the BMW guys as a streetable coilover kit that works well at the track. I will also replace the control arms with the Hartech motorsport versions of the genuine arms at the same time and fit the M030 spindles I have been sitting on to eliminate the brake adaptors and get a little clearance back between the tie rod ends. When that is all done I might finally consider fitting my freshly re-finished Turbo 3.6 Speedline wheels!
08-13-2015, 01:55 AM
#42
Drifting
Can't truly measure 50 rpm towards any realistic outcome towards efficiency/spool capability of the turbo/supercharger, etc.
08-13-2015, 09:17 AM
#44
Drifting
.
08-13-2015, 09:56 AM
#45
Rainman
Rennlist Member
Rennlist Member
Lol...and I always wanted the 6 speed as the 5 speed with the S2 ring and pinion REALLY needs another gear on the Motorway!! I'm not even sure that an expensive custom ring and pinion for the 6 speed would solve some of the issues. Probably need to go the even more costly aftermarket cogs although maybe 4-6 might suffice? Are the 968 gears interchangeable with the G50 sets?
S2 has a taller R/P than the NA and the early NA box cruises fine at 80mph/130kph, don't know what your motorway speed range is though
